Science.gov

Sample records for aisi type 316l

  1. On the corrosion resistance of AISI 316L-type stainless steel coated with manganese and annealed with flow of oxygen

    NASA Astrophysics Data System (ADS)

    Savaloni, Hadi; Agha-Taheri, Ensieh; Abdi, Fateme

    2016-06-01

    AISI 316L-type stainless steel was coated with 300-nm-thick Mn thin films and post-annealed at 673 K with a constant flow of oxygen (250 cm3/min). The films crystallographic and morphological structures were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM) before corrosion test and scanning electron microscopy (SEM) after corrosion test. Corrosion behavior of the samples in 0.3, 0.5 and 0.6 M NaCl solutions was investigated by means of potentiodynamic and electrochemical impedance spectroscopy (EIS) techniques. Results showed that the corrosion inhibition of annealed Mn/SS316L in all NaCl solutions with different concentrations is higher than that of bare SS316L. A correlation is achieved between the structural variation of the films with the potentiodynamic and EIS corrosion results.

  2. The tensile properties of AISI 316L and OPTIFER in various conditions irradiated in a spallation environment

    NASA Astrophysics Data System (ADS)

    Chen, J.; Rödig, M.; Carsughi, F.; Dai, Y.; Bauer, G. S.; Ullmaier, H.

    2005-08-01

    Tensile specimens, prepared from AISI 316L austenitic stainless steel in three conditions (solution-annealed, cold-worked and electron-beam welded) and from OPTIFER martensitic stainless steel in tempered condition, were irradiated in the Swiss spallation neutron source (SINQ) at 90-400 °C to displacement doses from 3 dpa to 11 dpa. The mechanical properties were measured by tensile testing at room temperature and 250 °C, respectively, and subsequent metallographic analysis was employed. The tensile results indicated that the strength of AISI 316L-SA is quite similar or a little higher than in 316L-EBW but elongation of SA 316L is somewhat larger than EBW for both unirradiated and irradiated samples. The cold-worked specimens revealed much higher strength but almost zero strain-to-necking after irradiation. The results from OPTIFER samples showed that irradiation hardening increases with dose, which is accompanied by a dramatic reduction of uniform elongation beginning at very low dose. The metallographic analysis showed that the samples of AISI 316L-EBW failed in the welded zone.

  3. Roughness Reduction in AISI 316L Stainless Steel after Surface Mechanical Attrition Treatment (SMAT)

    NASA Astrophysics Data System (ADS)

    Arifvianto, B.; Suyitno, Suyitno; Mahardika, M.

    2011-12-01

    Surface mechanical attrition treatment (SMAT) enhances the strength of metals by generating nanocrystallites at the surface layer. During the treatment, multiple impacts of milling balls are subjected to the treated surface. Consequently, the structure and roughness of the treated surface are also modified. In this paper, the effect of SMAT on the surface structure and roughness of an initially rough AISI 316L stainless steel is investigated. The SMAT was conducted for 0-20 minutes. The surface morphology, roughness, and volume loss due to the SMAT were studied. The result shows a decreasing roughness by the SMAT. An apparently deformed structure is also observed after 15 minutes of the treatment. However, no significant change in the volume loss is reported due to this treatment. Deformation by the multiple impacts is proposed to be the mechanism of the roughness reduction instead of microcutting by the milling balls during the SMAT.

  4. Characterization of irradiated AISI 316L stainless steel disks removed from the Spallation Neutron Source

    SciTech Connect

    Vevera, Bradley J; Hyres, James W; McClintock, David A; Riemer, Bernie

    2014-01-01

    Irradiated AISI 316L stainless steel disks were removed from the Spallation Neutron Source (SNS) for post-irradiation examination (PIE) to assess mechanical property changes due to radiation damage and erosion of the target vessel. Topics reviewed include high-resolution photography of the disk specimens, cleaning to remove mercury (Hg) residue and surface oxides, profile mapping of cavitation pits using high frequency ultrasonic testing (UT), high-resolution surface replication, and machining of test specimens using wire electrical discharge machining (EDM), tensile testing, Rockwell Superficial hardness testing, Vickers microhardness testing, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The effectiveness of the cleaning procedure was evident in the pre- and post-cleaning photography and permitted accurate placement of the test specimens on the disks. Due to the limited amount of material available and the unique geometry of the disks, machine fixturing and test specimen design were critical aspects of this work. Multiple designs were considered and refined during mock-up test runs on unirradiated disks. The techniques used to successfully machine and test the various specimens will be presented along with a summary of important findings from the laboratory examinations.

  5. Structural analysis and intergranular corrosion tests of AISI 316L steel.

    PubMed

    Stonawská, Z; Svoboda, M; Sozańska, M; Krístková, M; Sojka, J; Dagbert, C; Hyspecká, L

    2006-10-01

    Pure AISI 316L steel is investigated after solution heat treatment (1050 degrees C/H(2)O) and structural sensitization (650 degrees C). Two quite different intergranular corrosion tests are used to determine the degree of structural sensitization due to the precipitation of secondary phases along the grain boundaries (mainly the M(23)C(6) and sigma-phase): the oxalic acid etch test and the electrochemical potentio-kinetic reactivation test. Generally, the dissolution of chromium-rich carbides (M(23)C(6)) is provoked by oxalic acid etch tests, whereas the chromium-depleted zones, in the vicinity of chromium-rich carbides (M(23)C(6)), are attacked by electrochemical potentio-kinetic reactivation tests. Both intergranular corrosion tests are used to determine the maximum degree of structural sensitization. Thus structural analysis by carbon replicas reveals the Laves phase, and both the M(23)C(6) and (Cr,Mo)(x)(Fe,Ni)(y) phases. The results of intergranular corrosion tests are related to the findings of the structural analysis.

  6. Spinodal decomposition in AISI 316L stainless steel via high-speed laser remelting

    NASA Astrophysics Data System (ADS)

    Chikarakara, Evans; Naher, Sumsun; Brabazon, Dermot

    2014-05-01

    A 1.5 kW CO2 pulsed laser was used to melt the surface of AISI 316L stainless steel with a view to enhancing the surface properties for engineering applications. A 90 μm laser beam spot size focused onto the surface was used to provide high irradiances (up to 23.56 MW/cm2) with low residence times (as low as 50 μs) in order to induce rapid surface melting and solidification. Variations in microstructure at different points within the laser treated region were investigated. From this processing refined lamellar and nodular microstructures were produced. These sets of unique microstructures were produced within the remelted region when the highest energy densities were selected in conjunction with the lowest residence times. The transformation from the typical austenitic structure to much finer unique lamellar and nodular structures was attributed to the high thermal gradients achieved using these selected laser processing parameters. These structures resulted in unique characteristics including elimination of cracks and a reduction of inclusions within the treated region. Grain structure reorientation between the bulk alloy and laser-treated region occurred due to the induced thermal gradients. This present article reports on microstructure forms resulting from the high-speed laser surface remelting and corresponding underlying kinetics.

  7. Formation of Expanded Austenite on a Cold-Sprayed AISI 316L Coating by Low-Temperature Plasma Nitriding

    NASA Astrophysics Data System (ADS)

    Adachi, Shinichiro; Ueda, Nobuhiro

    2015-12-01

    Low-temperature plasma nitriding at temperatures below 450 °C is commonly applied to austenitic stainless steels to enhance wear resistance, while maintaining corrosion resistance, by forming expanded austenite (known as the S-phase). In this work, low-temperature plasma nitriding of cold-sprayed AISI 316L coatings was examined. A cold-spray technique was developed to produce metal coatings with less oxidation. However, the cold-sprayed AISI 316L coating obtained by use of nitrogen gas as propellant contained many interconnected pores and cracks, and was, consequently, unsuitable as an anticorrosive coating. Therefore, laser post-treatment was used to modify the coating and increase its density to similar to that of bulk steel. The anticorrosive performance of this coating on a carbon steel substrate in NaCl solution was substantially improved. Subsequent low-temperature plasma nitriding enhanced the wear resistance by two orders of magnitude. It is concluded that cold-sprayed AISI 316L coatings treated by laser post-treatment and subsequent low-temperature plasma nitriding could be used as protective coatings under severe wear and corrosion conditions.

  8. A Study on the Effects of the Use of Gas or Water Atomized AISI 316L Steel Powder on the Corrosion Resistance of Laser Deposited Material

    NASA Astrophysics Data System (ADS)

    Tobar, M. J.; Amado, J. M.; Montero, J.; Yáñez, A.

    Water atomized and gas atomized powders are commonly used in 3D laser manufacturing. Both types of AISI 316L stainless steel powders are available which differ in their manganese content. This is due to specific procedures related to the two different atomization process. The amount of manganese in the laser processed part might have important implications in its corrosion resistance. It could lead to the formation of manganese sulfides (MnS) which are known to be initiation sites for pitting corrosion. In this work, corrosion performance of laser deposited 316L steel using gas and atomized powders is compared by means of potentiodynamic polarization tests in 0.35%wt. NaCL solution. Worse performance of the gas atomized samples is observed as with respect to the water atomized ones in terms of polarization resistance, corrosion rate and pitting susceptibility.

  9. Corrosion and microstructural analysis data for AISI 316L and AISI 347H stainless steels after exposure to a supercritical water environment

    PubMed Central

    Ruiz, A.; Timke, T.; van de Sande, A.; Heftrich, T.; Novotny, R.; Austin, T.

    2016-01-01

    This article presents corrosion data and microstructural analysis data of austenitic stainless steels AISI 316L and AISI 347H exposed to supercritical water (25 MPa, 550 °C) with 2000 ppb of dissolved oxygen. The corrosion tests lasted a total of 1200 h but were interrupted at 600 h to allow measurements to be made. The microstructural data have been collected in the grain interior and at grain boundaries of the bulk of the materials and at the superficial oxide layer developed during the corrosion exposure. PMID:27158647

  10. Effects of AISI 316L corrosion products in in vitro bone formation.

    PubMed

    Morais, S; Sousa, J P; Fernandes, M H; Carvalho, G S; de Bruijn, J D; van Blitterswijk, C A

    1998-06-01

    Rat bone marrow cells were cultured in experimental conditions that favour the proliferation and differentiation of osteoblastic cells (i.e., 2.52 x 10(-4) mol l(-1) ascorbic acid, 10(-2) mol l(-1) beta-glycerophosphate and 10(-8) mol l(-1) dexamethasone) in the absence and in the presence of stainless-steel corrosion products, for a period of 18 days. An AISI 316L stainless-steel slurry (SS) was obtained by electrochemical means and the concentrations of the major metal ions, determined by atomic absorption spectrometry, were 8.78 x 10(-3) mol l(-1) of Fe, 4.31 x 10(-3) mol l(-1) of Cr and 2.56 x 10(-3) mol l(-1) of Ni. Bone marrow cells were exposed to 0.01, 0.1 and 1% of the SS and at the end of the incubation period, control and treated cultures were evaluated by histochemical assays for the identification of the presence of alkaline phosphatase and also calcium and phosphate deposition. Cultures were further observed by scanning electron microscopy. Levels of total and ionised calcium and phosphorus in the culture media collected from control and metal exposed cell cultures were also quantified. Histochemical staining showed that control cultures presented a strong reaction for the presence of alkaline phosphatase and exhibited formation of calcium and phosphates deposits. The presence of 0.01% SS caused no detectable biological effects in these cultures, 0.1% SS impaired osteoblastic behaviour and, 1% SS resulted in cell death. In the absence of bone cells, levels of total and ionised calcium and phosphorus in the control and metal added culture medium were similar throughout the incubation period. A significant decrease in the levels of ionised calcium and phosphorus were observed in the culture medium of control cultures and also in cultures exposed to 0.01% SS after two weeks of incubation, an event related with the formation of mineral calcium phosphate deposits in these cultures. In cultures grown in the presence of 0.1 and 1% SS corrosion products

  11. Effect of Filler Metals on the Weldability and Mechanical Properties of Multi-pass PCGTA Weldments of AISI 316L

    NASA Astrophysics Data System (ADS)

    Devendranath Ramkumar, K.; Maruthi Mohan Reddy, P.; Raja Arjun, B.; Choudhary, Ayush; Srivastava, Anubhav; Arivazhagan, N.

    2015-04-01

    The influence of filler metals on the microstructure, mechanical properties, and corrosion behavior of AISI 316L welds was investigated. Pulsed current gas tungsten arc welding was employed to join the AISI 316L plates using two different fillers ER2553 and ERNiCr-3. Microstructures studies showed the presence of different forms of austenite on employing ER2553 filler and formation of migrated grain boundaries at the weld zone while using ERNiCr-3 filler. Tensile studies corroborated that the tensile strength was greater for the weldments employing ER2553 filler. Charpy V-notch studies ascertained that the impact toughness was greater for ER2553 weldments as compared to the parent metal. Potentiodynamic polarization curves clearly inferred that the weld zone of ER2553 exhibited better corrosion resistance among the various coupons tested. It was concluded from the study that ER2553 exhibited better mechanical and corrosion properties and could be adopted to achieve optimal properties compared to over-alloyed filler.

  12. Improving the Adhesion Resistance of the Boride Coatings to AISI 316L Steel Substrate by Diffusion Annealing

    NASA Astrophysics Data System (ADS)

    Campos-Silva, I.; Bernabé-Molina, S.; Bravo-Bárcenas, D.; Martínez-Trinidad, J.; Rodríguez-Castro, G.; Meneses-Amador, A.

    2016-07-01

    In this study, new results about the practical adhesion resistance of boride coating/substrate system formed at the surface of AISI 316 L steel and improved by means of a diffusion annealing process are presented. First, the boriding of AISI 316 L steel was performed by the powder-pack method at 1173 K with different exposure times (4-8 h). The diffusion annealing process was conducted on the borided steels at 1273 K with 2 h of exposure using a diluent atmosphere of boron powder mixture. The mechanical behavior of the boride coating/substrate system developed by both treatments was established using Vickers and Berkovich tests along the depth of the boride coatings, respectively. Finally, for the entire set of experimental conditions, the scratch tests were performed with a continuously increasing normal force, in which the practical adhesion resistance of the boride coating/substrate system was represented by the critical load. The failure mechanisms developed over the surface of the scratch tracks were analyzed; the FeB-Fe2B/substrate system exhibited an adhesive mode, while the Fe2B/substrate system obtained by the diffusion annealing process showed predominantly a cohesive failure mode.

  13. Improving the Adhesion Resistance of the Boride Coatings to AISI 316L Steel Substrate by Diffusion Annealing

    NASA Astrophysics Data System (ADS)

    Campos-Silva, I.; Bernabé-Molina, S.; Bravo-Bárcenas, D.; Martínez-Trinidad, J.; Rodríguez-Castro, G.; Meneses-Amador, A.

    2016-09-01

    In this study, new results about the practical adhesion resistance of boride coating/substrate system formed at the surface of AISI 316 L steel and improved by means of a diffusion annealing process are presented. First, the boriding of AISI 316 L steel was performed by the powder-pack method at 1173 K with different exposure times (4-8 h). The diffusion annealing process was conducted on the borided steels at 1273 K with 2 h of exposure using a diluent atmosphere of boron powder mixture. The mechanical behavior of the boride coating/substrate system developed by both treatments was established using Vickers and Berkovich tests along the depth of the boride coatings, respectively. Finally, for the entire set of experimental conditions, the scratch tests were performed with a continuously increasing normal force, in which the practical adhesion resistance of the boride coating/substrate system was represented by the critical load. The failure mechanisms developed over the surface of the scratch tracks were analyzed; the FeB-Fe2B/substrate system exhibited an adhesive mode, while the Fe2B/substrate system obtained by the diffusion annealing process showed predominantly a cohesive failure mode.

  14. Effects of Ti-C:H coating and plasma nitriding treatment on tribological, electrochemical, and biocompatibility properties of AISI 316L.

    PubMed

    Kao, W H; Su, Y L; Horng, J H; Zhang, K X

    2016-08-01

    Ti-C:H coatings were deposited on original, nitrided, and polished-nitrided AISI 316L stainless steel substrates using a closed field unbalanced magnetron sputtering system. Sliding friction wear tests were performed in 0.89 wt.% NaCl solution under a load of 30 N against AISI 316L stainless steel, Si3N4, and Ti6Al4V balls, respectively. The electrochemical properties of the various specimens were investigated by means of corrosion tests performed in 0.89 wt.% NaCl solution at room temperature. Finally, the biocompatibility properties of the specimens were investigated by performing cell culturing experiments using purified mouse leukemic monocyte macrophage cells (Raw264.7). In general, the results showed that plasma nitriding followed by Ti-C:H coating deposition provides an effective means of improving the wear resistance, anti-corrosion properties, and biocompatibility performance of AISI 316L stainless steel.

  15. Effect of Surface Treatment on the Surface Characteristics of AISI 316L Stainless Steel

    NASA Technical Reports Server (NTRS)

    Trigwell, Steve; Selvaduray, Guna

    2005-01-01

    The ability of 316L stainless steel to maintain biocompatibility, which is dependent upon the surface characteristics, is critical to its effectiveness as an implant material. The surfaces of mechanically polished (MP), electropolished (EP) and plasma treated 316L stainless steel coupons were characterized by X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES) for chemical composition, Atomic Force Microscopy for surface roughness, and contact angle measurements for critical surface tension. All surfaces had a Ni concentration that was significantly lower than the bulk concentration of -43%. The Cr content of the surface was increased significantly by electropolishing. The surface roughness was also improved significantly by electropolishing. Plasma treatment had the reverse effect - the surface Cr content was decreased. It was also found that the Cr and Fe in the surface exist in both the oxide and hydroxide states, with the ratios varying according to surface treatment.

  16. Corrosion resistance of multilayer hybrid sol-gel coatings deposited on the AISI 316L austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Caballero, Y. T.; Rondón, E. A.; Rueda, L.; Hernández Barrios, C. A.; Coy, A.; Viejo, F.

    2016-02-01

    In the present work multilayer hybrid sol-gel coatings were synthesized on the AISI 316L austenitic stainless steel employed in the fabrication of orthopaedic implants. Hybrid sols were obtained from a mixture of inorganic precursor, TEOS, and organic, GPTMS, using ethanol as solvent, and acetic acid as catalyst. The characterization of the sols was performed using pH measurements, rheological tests and infrared spectroscopy (FTIR) for different ageing times. On the other hand, the coatings were characterized by scanning electron microscopy (SEM), while the corrosion resistance was evaluated using anodic potentiodynamic polarization in SBF solution at 37±2°C. The results confirmed that sol-gel synthesis employing TEOS-GPTMS systems produces uniform and homogeneous coatings, which enhanced the corrosion resistance with regard to the parent alloy. Moreover, corrosion performance was retained after applying more than one layer (multilayer coatings).

  17. Electron Backscatter Diffraction Analysis of Joints Between AISI 316L Austenitic/UNS S32750 Dual-Phase Stainless Steel

    NASA Astrophysics Data System (ADS)

    Shamanian, Morteza; Mohammadnezhad, Mahyar; Amini, Mahdi; Zabolian, Azam; Szpunar, Jerzy A.

    2015-08-01

    Stainless steels are among the most economical and highly practicable materials widely used in industrial areas due to their mechanical and corrosion resistances. In this study, a dissimilar weld joint consisting of an AISI 316L austenitic stainless steel (ASS) and a UNS S32750 dual-phase stainless steel was obtained under optimized welding conditions by gas tungsten arc welding technique using AWS A5.4:ER2594 filler metal. The effect of welding on the evolution of the microstructure, crystallographic texture, and micro-hardness distribution was also studied. The weld metal (WM) was found to be dual-phased; the microstructure is obtained by a fully ferritic solidification mode followed by austenite precipitation at both ferrite boundaries and ferrite grains through solid-state transformation. It is found that welding process can affect the ferrite content and grain growth phenomenon. The strong textures were found in the base metals for both steels. The AISI 316L ASS texture is composed of strong cube component. In the UNS S32750 dual-phase stainless steel, an important difference between the two phases can be seen in the texture evolution. Austenite phase is composed of a major cube component, whereas the ferrite texture mainly contains a major rotated cube component. The texture of the ferrite is stronger than that of austenite. In the WM, Kurdjumov-Sachs crystallographic orientation relationship is found in the solidification microstructure. The analysis of the Kernel average misorientation distribution shows that the residual strain is more concentrated in the austenite phase than in the other phase. The welding resulted in a significant hardness increase in the WM compared to initial ASS.

  18. Residual stress in nano-structured stainless steel (AISI 316L) prompted by Xe+ ion bombardment at different impinging angles

    NASA Astrophysics Data System (ADS)

    Cucatti, S.; Droppa, R.; Figueroa, C. A.; Klaus, M.; Genzel, Ch.; Alvarez, F.

    2016-10-01

    The effect of low energy (<1 keV) xenon (Xe+) ion bombardment on the residual stress of polycrystalline iron alloy (AISI 316L steel) is reported. The results take into account the influence of the ion incident angle maintaining constant all other bombarding parameters (i.e., ion energy and current density, temperature, and doses). The bombarded surface topography shows that ions prompt the formation of nanometric regular patterns on the surface crystalline grains and stressing the structure. The paper focalizes on the study of the surface residual stress state stemming from the ion bombardment studied by means of the "sin2 ψ" and "Universal Plot" methods. The analysis shows the absence of shear stress in the affected material region and the presence of compressive in-plane residual biaxial stress (˜200 MPa) expanding up to ˜1 μm depth for all the studied samples. Samples under oblique bombardment present higher compressive stress values in the direction of the projected ion beam on the bombarded surface. The absolute value of the biaxial surface stress difference (σ11-σ22) increases on ion impinging angles, a phenomenon associated with the momentum transfer by the ions. The highest stress level was measured for ion impinging angles of 45° ( σ 11 = -380 ± 10 MPa and σ 22 = -320 ± 10 MPa). The different stresses obtained in the studied samples do not affect significantly the formation of characteristic surface patterns.

  19. Effects of Thermal Aging on Material Properties, Stress Corrosion Cracking, and Fracture Toughness of AISI 316L Weld Metal

    NASA Astrophysics Data System (ADS)

    Lucas, Timothy; Forsström, Antti; Saukkonen, Tapio; Ballinger, Ronald; Hänninen, Hannu

    2016-08-01

    Thermal aging and consequent embrittlement of materials are ongoing issues in cast stainless steels, as well as duplex, and high-Cr ferritic stainless steels. Spinodal decomposition is largely responsible for the well-known "748 K (475 °C) embrittlement" that results in drastic reductions in ductility and toughness in these materials. This process is also operative in welds of either cast or wrought stainless steels where δ-ferrite is present. While the embrittlement can occur after several hundred hours of aging at 748 K (475 °C), the process is also operative at lower temperatures, at the 561 K (288 °C) operating temperature of a boiling water reactor (BWR), for example, where ductility reductions have been observed after several tens of thousands of hours of exposure. An experimental program was carried out in order to understand how spinodal decomposition may affect changes in material properties in Type 316L BWR piping weld metals. The study included material characterization, nanoindentation hardness, double-loop electrochemical potentiokinetic reactivation (DL-EPR), Charpy-V, tensile, SCC crack growth, and in situ fracture toughness testing as a function of δ-ferrite content, aging time, and temperature. SCC crack growth rates of Type 316L stainless steel weld metal under simulated BWR conditions showed an approximate 2 times increase in crack growth rate over that of the unaged as-welded material. In situ fracture toughness measurements indicate that environmental exposure can result in a reduction of toughness by up to 40 pct over the corresponding at-temperature air-tested values. Material characterization results suggest that spinodal decomposition is responsible for the degradation of material properties measured in air, and that degradation of the in situ properties may be a result of hydrogen absorbed during exposure to the high-temperature water environment.

  20. Effect of Welding Current and Time on the Microstructure, Mechanical Characterizations, and Fracture Studies of Resistance Spot Welding Joints of AISI 316L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Kianersi, Danial; Mostafaei, Amir; Mohammadi, Javad

    2014-09-01

    This article aims at investigating the effect of welding parameters, namely, welding current and welding time, on resistance spot welding (RSW) of the AISI 316L austenitic stainless steel sheets. The influence of welding current and welding time on the weld properties including the weld nugget diameter or fusion zone, tensile-shear load-bearing capacity of welded materials, failure modes, energy absorption, and microstructure of welded nuggets was precisely considered. Microstructural studies and mechanical properties showed that the region between interfacial to pullout mode transition and expulsion limit is defined as the optimum welding condition. Electron microscopic studies indicated different types of delta ferrite in welded nuggets including skeletal, acicular, and lathy delta ferrite morphologies as a result of nonequilibrium phases, which can be attributed to a fast cooling rate in the RSW process. These morphologies were explained based on Shaeffler, WRC-1992, and pseudo-binary phase diagrams. The optimum microstructure and mechanical properties were achieved with 8-kA welding current and 4-cycle welding time in which maximum tensile-shear load-bearing capacity or peak load of the welded materials was obtained at 8070 N, and the failure mode took place as button pullout with tearing from the base metal. Finally, fracture surface studies indicated that elongated dimples appeared on the surface as a result of ductile fracture in the sample welded in the optimum welding condition.

  1. Cultures and co-cultures of human blood mononuclear cells and endothelial cells for the biocompatibility assessment of surface modified AISI 316L austenitic stainless steel.

    PubMed

    Stio, Maria; Martinesi, Maria; Treves, Cristina; Borgioli, Francesca

    2016-12-01

    Samples of AISI 316L austenitic stainless steel were subjected either to grinding and polishing procedure, or to grinding and then low temperature glow-discharge nitriding treatment, or to grinding, nitriding and subsequently coating with collagen-I. Nitrided samples, even if only ground, show a higher corrosion resistance in PBS solution, in comparison with ground and polished AISI 316L. Biocompatibility was evaluated in vitro by incubating the samples with either peripheral blood mononuclear cells (PBMC) or human umbilical vein endothelial cells (HUVEC), tested separately or in co-culture. HUVEC-PBMC co-culture and co-incubation of HUVEC with PBMC culture medium, after the previous incubation of PBMC with metallic samples, allowed to determine whether the incubation of PBMC with the different samples might affect HUVEC behaviour. Many biological parameters were considered: cell proliferation, release of cytokines, matrix metalloproteinases (MMPs) and sICAM-1, gelatinolytic activity of MMPs, and ICAM-1 protein expression. Nitriding treatment, with or without collagen coating of the samples, is able to ameliorate some of the biological parameters taken into account. The obtained results point out that biocompatibility may be successfully tested in vitro, using cultures of normal human cells, as blood and endothelial cells, but more than one cell line should be used, separately or in co-culture, and different parameters should be determined, in particular those correlated with inflammatory phenomena. PMID:27612806

  2. Ion Beam Analysis, structure and corrosion studies of nc-TiN/a-Si3N4 nanocomposite coatings deposited by sputtering on AISI 316L

    NASA Astrophysics Data System (ADS)

    García, J.; Canto, C. E.; Flores, M.; Andrade, E.; Rodríguez, E.; Jiménez, O.; Solis, C.; de Lucio, O. G.; Rocha, M. F.

    2014-07-01

    In this work, nanocomposite coatings of nc-TiN/a-Si3N4, were deposited on AISI 316L stainless steel substrate by a DC and RF reactive magnetron co-sputtering technique using an A-N2 plasma. The structure of the coatings was characterized by means of XRD (X-ray Diffraction). The substrate and coating corrosion resistance were evaluated by potentiodynamic polarization using a Ringer solution as electrolyte. Corrosion tests were conducted with the purpose to evaluate the potential of this coating to be used on biomedical alloys. IBA (Ion Beam Analysis) techniques were applied to measure the elemental composition profiles of the films and, XPS (X-ray Photoelectron Spectroscopy) were used as a complementary technique to obtain information about the compounds present in the films. The nanocomposite coatings of nc-TiN/a-Si3N4 show crystalline (TiN) and amorphous (Si3N4) phases which confer a better protection against the corrosion effects compared with that of the AISI 316L.

  3. Re-weldability of neutron irradiated Type 304 and 316L stainless steels

    NASA Astrophysics Data System (ADS)

    Morishima, Y.; Koshiishi, M.; Kashiwakura, K.; Hashimoto, T.; Kawano, S.

    2004-08-01

    Weldability of irradiated stainless steel (SS) has been studied to develop the technical guideline regarding the repair-welding of reactor internals. Type 304 and 316L SSs were irradiated at ambient temperature in the US Advanced Test Reactor. The multi-pass bead-on-plate TIG (GTA) and YAG laser welding with heat input levels less than 1 MJ/m were performed on specimens containing helium up to 18 appm. In this paper, results of cross-sectional micrograph observations of the heat affected zone were considered in light of helium bubble properties. The tendency for weld crack formation of irradiated Type 316L SS was compared with that of irradiated Type 304 SS.

  4. Study of scale formation on AISI 316L in simulated solid oxide fuel cell bi-polar environments

    SciTech Connect

    Ziomek-Moroz, M.; Covino, Bernard S., Jr.; Cramer, Stephen D.; Holcomb, Gordon R.; Bullard, Sophie J.; Singh , P.; Windisch, C.F., Jr.

    2004-01-01

    Significant progress made towards reducing the operating temperature of solid oxide fuel cells (SOFC) from {approx}1000 C to {approx}600 C is expected to permit the use of metallic materials with substantial cost reduction. One of the components in a SOFC stack to be made of metallic materials is a bipolar separator, also called an interconnect. It provides electrical connection between individual cells and serves as a gas separator to prevent mixing of the fuel and air. At operating temperature, the material selected for interconnects should possess good chemical and mechanical stability in complex fuel and oxidant gaseous environments, good electrical conductivity, and a coefficient of thermal expansion (CTE) that matches that of the cathode, anode, and electrolyte components. Cr2O3 scale-forming alloys appear to be the most promising candidates. There appears to be a mechanism whereby the environment on the fuel side of a stainless steel interconnect changes the corrosion behavior of the metal on the air side. The corrosion behavior of 316L stainless steel simultaneously exposed to air on one side and H2+3%H2O on the other at 907 K was studied using X-ray diffraction (XRD) and Raman spectroscopy. The electrical property of the investigated material was determined in terms of area-specific resistance (ASR). The chemical and electrical properties of 316L exposed to a dual environment of air/ (H2+H2O) were compared to those of 316L exposed to a single environment of air/air.

  5. Influence of cold plastic deformation on critical pitting potential of AISI 316 L and 304 L steels in an artificial physiological solution simulating the aggressiveness of the human body.

    PubMed

    Cigada, A; Mazza, B; Pedeferri, P; Sinigaglia, D

    1977-07-01

    The effect of cold working on critical pitting potential of AISI 316 L and 304 L steels in a buffered physiological solution has been studied. In particular, the importance of deformation degree, orientation of the specimen surface to the deformation direction, and cold working temperature in lowering the critical pitting potential is shown. PMID:873942

  6. Cross-sectional transmission electron microscopy of ultra-fine wires of AISI 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Wang, H. S.; Wei, R. C.; Huang, C. Y.; Yang, J. R.

    2006-01-01

    Starting with 190?µm diameter wire of 316L stainless steel, ultra-thin wire just 8?µm in diameter has been made and characterized. There was no intermediate heat treatment used in the process of drawing, and the amount of true stain was about 6.3. A specimen preparation method for the cross-sectional transmission electron microscopy (TEM) of ultra-fine wires of 316L stainless steel has been developed. The ultra-fine wire was sandwiched between silicon chips and the bonded assembly then sliced to produce longitudinal and transverse sections of the wire in a form suitable for further processing into electron transparent samples. TEM reveals that the heavily deformed wire consists of nanoscale fine elongated structures along the drawing direction. The diffraction patterns indicate that a substantial amount of austenite has transformed into martensite. The TEM dark field images show nanosized patches of martensite distributed among the debris of austenite along the drawing direction. The evidence strongly suggests that severe deformation leads to mechanical stabilization of austenite against the growth of martensite.

  7. The effect of CO2 laser beam welded AISI 316L austenitic stainless steel on the viability of fibroblast cells, in vitro.

    PubMed

    Köse, Ceyhun; Kaçar, Ramazan; Zorba, Aslı Pınar; Bağırova, Melahat; Allahverdiyev, Adil M

    2016-03-01

    It has been determined by the literature research that there is no clinical study on the in vivo and in vitro interaction of the cells with the laser beam welded joints of AISI 316L biomaterial. It is used as a prosthesis and implant material and that has adequate mechanical properties and corrosion resistance characteristics. Therefore, the interaction of the CO2 laser beam welded samples and samples of the base metal of AISI 316L austenitic stainless steel with L929 fibroblast cells as an element of connective tissue under in vitro conditions has been studied. To study the effect of the base metal and the laser welded test specimens on the viability of the fibroblast cells that act as an element of connective tissues in the body, they were kept in DMEMF-12 medium for 7, 14, 28 days and 18 months. The viability study was experimentally studied using the MTT method for 7, 14, 28 days. In addition, the direct interaction of the fibroblast cells seeded on 6 different plates with the samples was examined with an inverted microscope. The MTT cell viability experiment was repeated on the cells that were in contact with the samples. The statistical relationship was analyzed using a Tukey test for the variance with the GraphPad statistics software. The data regarding metallic ion release were identified with the ICP-MS method after the laser welded and main material samples were kept in cell culture medium for 18 months. The cell viability of the laser welded sample has been detected to be higher than that of the base metal and the control based on 7th day data. However, the laser welded sample's viability of the fibroblast cells has diminished by time during the test period of 14 and 28 days and base metal shows better viability when compared to the laser welded samples. On the other hand, the base metal and the laser welded sample show better cell viability effect when compared to the control group. According to the ICP-MS results of the main material and laser welded

  8. Effect of Mercury Velocity on Corrosion of Type 316L Stainless Steel in a Thermal Convection Loop

    SciTech Connect

    Pawel, SJ

    2001-03-23

    Two 316L thermal convection loops (TCLs) containing several types of 316L specimens circulated mercury continuously for 2000 h at a maximum temperature of 300 C. Each TCL was fitted with a venturi-shaped reduced section near the top of the hot leg for the purpose of locally increasing the Hg velocity. Results suggest that an increase in velocity from about 1.2 m/min (bulk flow) to about 5 mmin (reduced section) had no significant impact on compatibility of 316L with Hg. In addition, various surface treatments such as gold-plating, chemical etching, polishing, and steam cleaning resulted in little or no influence on compatibility of 316L with Hg when compared to nominal mill-annealed/surface-ground material. A sensitizing heat treatment also had little/no effect on compatibility of 316L with Hg for the bulk specimen, although intergranular attack was observed around the specimen holes in each case. It was determined that carburization of the hole area had occurred as a result of the specimen fabrication process potentially rendering the specimens susceptible to corrosion by Hg at these locations. To avoid sensitization-related compatibility issues for SNS components, selection of low carbon grades of stainless steel and control of the fabrication process is recommended.

  9. Influences of deposition strategies and oblique angle on properties of AISI316L stainless steel oblique thin-walled part by direct laser fabrication

    NASA Astrophysics Data System (ADS)

    Wang, Xinlin; Deng, Dewei; Qi, Meng; Zhang, Hongchao

    2016-06-01

    Direct laser fabrication (DLF) developed from laser cladding and rapid prototyping technique has been widely used to fabricate thin-walled parts exhibiting more functions without expending weight and size. Oblique thin-walled parts accompanied with inhomogeneous mechanical properties are common in application. In the present study, a series of AISI316L stainless steel oblique thin-walled parts are successfully produced by DLF, in addition, deposition strategies, microstructure, and mechanical property of the oblique thin-walled parts are investigated. The results show that parallel deposition way is more valuable to fabricate oblique thin-walled part than oblique deposition way, because of the more remarkable properties. The hardness of high side initially increases until the distance to the substrate reaches about 25 mm, and then decreases with the increase of the deposition height. Oblique angle has a positive effect on the tensile property but a negative effect on microstructure, hardness and elongation due to the more tempering time. The maximum average ultimate tensile strength (UTS) and elongation are presented 744.3 MPa and 13.5% when the angle between tensile loading direction and horizontal direction is 45° and 90°, respectively.

  10. Precipitation in AISI 316L(N) during creep tests at 550 and 600 °C up to 10 years

    NASA Astrophysics Data System (ADS)

    Padilha, A. F.; Escriba, D. M.; Materna-Morris, E.; Rieth, M.; Klimenkov, M.

    2007-05-01

    The precipitation behaviour in the gauge lengths and in the heads of initially solution annealed type 316L(N) austenitic stainless steel specimens tested in creep at 550 and 600 °C for periods of up to 85 000 h has been studied using several metallographic techniques. Three phases were detected: M 23C 6, Laves, and sigma phase. The volume fraction of the precipitated sigma phase was significantly higher than that of carbides and the Laves phase. M 23C 6 carbide precipitation occurred very rapidly and was followed by the sigma and Laves phases formation in the delta ferrite islands. Sigma and Laves phases precipitated at grain boundaries after longer times. Two different mechanisms of sigma phase precipitation have been proposed, one for delta ferrite decomposition and another for grain boundary precipitation. Small quantities of the Laves phase were detected in delta ferrite, at grain boundaries and inside the grains.

  11. Effects of tritium on corrosion of welded type 316L stainless steel

    SciTech Connect

    Bellanger, G.

    1995-01-01

    An attempt was undertaken to investigate the localized corrosion susceptibility of tritiated oxidized weldments of Type 316L austenitic stainless steel made by the tungsten inert gas process. For this, the distribution of tritium at the surface was determined using a scintillation spectrophotometer. Depending on the values, the amounts of tritium are high enough to degrade the oxide. The polarization curves show a corrosion potential lower than that of a nontritiated weld. This means that tritiated welds have a less {open_quotes}noble{close_quotes}behavior. It is observed by voltammetry that the reduction of corrosion products always occurs during the cathodic scans, meaning less passivity for tritiated welds. Using electro-chemical impedance spectroscopy, the values of electron and ionic diffusion within the passive oxide were deduced. The tritiated oxide layer is thinner, and a higher concentration of electron carriers is observed; this indicates a less insulating oxide. The difference in electron carriers may come from ionization and breakdowns of the oxide layer by tritium and the energy released. The scanning electron microscopy (SEM) examinations show a complex microstructure of the tritiated surface that could be attributed both to the welding process and a severe degradation by tritium and energy released from the decay. It is well known that the ferrite is formed in the austenite during welding; this currently leads to corrosion of ferrite/austenite surface borders. This corrosion may be facilitated by the presence of tritium trapped at these surface borders, and the microcracks would nucleate leading to no cohesion of austenite. This mechanism is difficult to verify by SEM for stainless steel highly degraded by tritium and the energy released, but the visual examinations would appear to well support the results obtained by electrochemical methods, where the oxide is damaged. 28 refs., 15 figs., 3 tabs.

  12. Electrochemical study of Type 304 and 316L stainless steels in simulated body fluids and cell cultures.

    PubMed

    Tang, Yee-Chin; Katsuma, Shoji; Fujimoto, Shinji; Hiromoto, Sachiko

    2006-11-01

    The electrochemical corrosion behaviour of Type 304 and 316L stainless steels was studied in Hanks' solution, Eagle's minimum essential medium (MEM), serum containing medium (MEM with 10% of fetal bovine serum) without cells, and serum containing medium with cells over a 1-week period. Polarization resistance measurements indicated that the stainless steels were resistant to Hanks' and MEM solutions. Type 304 was more susceptible to pitting corrosion than Type 316L in Hanks' and MEM solutions. The uniform corrosion resistance of stainless steels, determined by R(p), was lower in culturing medium than in Hanks' and MEM. The low corrosion resistance was due to surface passive film with less protective to reveal high anodic dissolution rate. When cells were present, the initial corrosion resistance was low, but gradually increased after 3 days, consistent with the trend of cell coverage. The presence of cells was found to suppress the cathodic reaction, that is, oxygen reduction, and increase the uniform corrosion resistance as a consequence. On the other hand, both Type 304 and 316L stainless steels became more susceptible to pitting corrosion when they were covered with cells.

  13. Creep deformation and fracture behavior of types 316 and 316L(N) stainless steels and their weld metals

    NASA Astrophysics Data System (ADS)

    Sasikala, G.; Mannan, S. L.; Mathew, M. D.; Rao, K. Bhanu

    2000-04-01

    The creep properties of a nuclear-grade type 316(L) stainless steel (SS) alloyed with nitrogen (316L(N) SS) and its weld metal were studied at 873 and 923 K in the range of applied stresses from 100 to 335 MPa. The results were compared with those obtained on a nuclear-grade type 316 SS, which is lean in nitrogen. The creep rupture lives of the weld metals were found to be lower than those of the respective base metals by a factor of 5 to 10. Both the base and weld metals of 316L(N) SS exhibited better resistance to creep deformation compared to their 316 SS counterparts at identical test conditions. A power-law relationship between the minimum creep rate and applied stress was found to be obeyed for both the base and weld metals. Both the weld metals generally exhibited lower rupture elongation than the respective base metals; however, at 873 K, the 316 SS base and weld metals had similar rupture elongation at identical applied stresses. Comparison of the rupture lives of the two steels to the ASME curves for the expected minimum stress to rupture for 316 SS base and weld metals showed that, for 316L(N) SS, the specifications for maximum allowable stresses based on data for 316 SS could prove overconservative. The influence of nitrogen on the creep deformation and fracture behavior, especially in terms of its modifying the precipitation kinetics, is discussed in light of the microstructural observations. In welds containing δ ferrite, the kinetics of its transformation and the nature of the transformation products control the deformation and fracture behavior. The influence of nitrogen on the δ ferrite transformation behavior and coarsening kinetics is also discussed, on the basis of extensive characterization by metallographic techniques.

  14. Corrosion of type 316L stainless steel in a mercury thermal convection loop

    SciTech Connect

    DiStefano, J.R.; Manneschmidt, E.T.; Pawel, S.J.

    1999-04-01

    Two thermal convection loops fabricated from 316L stainless steel containing mercury (Hg) and Hg with 1000 wppm gallium (Ga), respectively, were operated continuously for about 5000 h. In each case, the maximum loop temperature was constant at about 305 degrees C and the minimum temperature was constant at about 242 degrees C. Coupons in the hot leg of the Hg-loop developed a posous surface layer substantially depleted of nickel and chromium, which resulted in a transformation to ferrite. The coupon exposed at the top of the hot leg in the Hg-loop experienced the maximum degradation, exhibiting a surface layer extending an average of 9-10 mu m after almost 5000 h. Analysis of the corrosion rate data as a function of temperature (position) in the Hg-loop suggests wetting by the mer cury occurred only above about 255 degrees C and that the rate limiting step in the corrosion process above 255 degrees C is solute diffusion through the saturated liquid boundary layer adjacent to the corroding surface. The latter factor suggests that the corrosion of 316L stainless steel in a mercury loop may be velocity dependent. No wetting and no corrosion were observed on the coupons and wall specimens removed from the Hg/Ga loop after 5000 h of operation.

  15. Material Corrosion and Plate-Out Test of Types 304L and 316L Stainless Steel

    SciTech Connect

    Zapp, P.E.

    2001-02-06

    Corrosion and plate-out tests were performed on 304L and 316L stainless steel in pretreated Envelope B and Envelope C solutions. Flat coupons of the two stainless steels were exposed to 100 degrees C liquid and to 74 degrees C and 88 degrees C vapor above the solutions for 61 days. No significant corrosion was observed either by weight-loss measurements or by microscopic examination. Most coupons had small weight gains due to plate-out of solids, which remained to some extent even after 24-hour immersion in 1 N nitric acid at room temperature. Plate-out was more significant in the Envelope B coupons, with film thickness from less than 0.001 in. to 0.003-inches.

  16. Helium 3 precipitation in AISI 316L stainless steel induced by radioactive decay of tritium: Microstructural study of helium bubble precipitation

    NASA Astrophysics Data System (ADS)

    Brass, A. M.; Chanfreau, A.; Chene, J.

    1994-10-01

    This article deals with the study of the influence of thermomechanical heat treatments, aging conditions (temperature and time), and helium concentration on helium bubble precipitation in a 316L austenitic steel. Helium was generated by the radioactive decay of tritium (tritium trick). Helium bubbles impede the grain growth in 316L steel aged at 1373 K and also the recrystal-lization reaction at this temperature if cold working is performed prior to aging. Transmission electron microscopy (TEM) observations indicated a weak helium precipitation at 1073 and 1223 K, presumably due to the presence of trapping sites for tritium, and no bubble growth after aging up to 100 hours. Precipitation sites are mainly dislocations in the matrix at 1073 K and grain boundaries and individual dislocations in the matrix at 1223 K. The large bubble size (50 nm) observed at 1373 K, even for short aging times (0.083 hour), can partly be attributed to bubble dragging by dislocations toward the grain boundaries. Cold deformation prior to aging leads to a larger bubble size due to growth enhancement during recrystallization. Decreasing the helium content leads to a smaller helium bubble size and density. Tritium trapping at helium bubbles may favor helium 3 accumulation on defects such as grain boundaries, as observed by tritium autoradiography.

  17. Performance Optimization of Cold Rolled Type 316L Stainless Steel by Sand Blasting and Surface Linishing Treatment

    NASA Astrophysics Data System (ADS)

    Krawczyk, B.; Heine, B.; Engelberg, D. L.

    2016-03-01

    Sand blasting followed by a surface linishing treatment was applied to optimize the near-surface microstructure of cold rolled type 316L stainless steel. The introduction of cold rolling led to the formation of α-martensite. Specimens with large thickness reductions (40, 53%) were more susceptible to localized corrosion. The application of sand blasting produced a near-surface deformation layer containing compressive residual stresses with significantly increased surface roughness, resulting in reduced corrosion resistance. The most resistant microstructure was obtained with the application of a final linishing treatment after sand blasting. This treatment produced microstructures with compressive near-surface residual stresses, reduced surface roughness, and increased resistance to localized corrosion.

  18. Radiation-induced stress relaxation in high temperature water of type 316L stainless steel evaluated by neutron diffraction

    NASA Astrophysics Data System (ADS)

    Ishiyama, Y.; Rogge, R. B.; Obata, M.

    2011-01-01

    Weld beads on plate specimens made of type 316L stainless steel were neutron-irradiated up to about 2.5 × 10 25 n/m 2 ( E > 1 MeV) at 561 K in the Japan Material Testing Reactor (JMTR). Residual stresses of the specimens were measured by the neutron diffraction method, and the radiation-induced stress relaxation was evaluated. The values of σ x residual stress (transverse to the weld bead) and σ y residual stress (longitudinal to the weld bead) decreased with increasing neutron dose. The tendency of the stress relaxation was almost the same as previously published data, which were obtained for type 304 stainless steel. From this result, it was considered that there was no steel type dependence on radiation-induced stress relaxation. The neutron irradiation dose dependence of the stress relaxation was examined using an equation derived from the irradiation creep equation. The coefficient of the stress relaxation equation was obtained, and the value was 1.4 (×10 -6/MPa/dpa). This value was smaller than that of nickel alloy.

  19. Effect of thermal treatment on the corrosion resistance of Type 316L stainless steel exposed in supercritical water

    NASA Astrophysics Data System (ADS)

    Jiao, Y.; Zheng, W.; Guzonas, D. A.; Cook, W. G.; Kish, J. R.

    2015-09-01

    There are still unknown aspects about the growth mechanism of oxide scales formed on candidate stainless steel fuel cladding materials during exposure in supercritical water (SCW) under the conditions relevant to the Canadian supercritical water-cooled reactor (SCWR). The tendency for intermetallic precipitates to form within the grains and on grain boundaries during prolonged exposure at high temperatures represents an unknown factor to corrosion resistance, since they tend to bind alloyed Cr. The objective of this study was to better understand the extent to which intermetallic precipitates affects the mode and extent of corrosion in SCW. Type 316L stainless steel, used as a model Fe-Cr-Ni-Mo alloy, was exposed to 25 MPa SCW at 550 °C for 500 h in a static autoclave for this purpose. Mechanically-abraded samples were tested in the mill-annealed (MA) and a thermally-treated (TT) condition. The thermal treatment was conducted at 815 °C for 1000 h to precipitate the carbide (M23C6), chi (χ), laves (η) and sigma (σ) phases. It was found that although relatively large intermetallic precipitates formed at the scale/alloy interface locally affected the oxide scale formation, their discontinuous formation did not affect the short-term overall apparent corrosion resistance.

  20. The passivity of Type 316L stainless steel in borate buffer solution

    NASA Astrophysics Data System (ADS)

    Nicic, Igor; Macdonald, Digby D.

    2008-09-01

    The passivity of Type 316 SS in borate buffer solution (pH 8.35), in the steady-state, has been explored using a variety of electrochemical techniques, including potentiostatic polarization, Mott Schottky analysis, and electrochemical impedance spectroscopy. The study shows that the passive film is an n-type semiconductor with a donor density that is essentially independent of voltage across the passive state. The passive current density is also found to be voltage-independent, but the thickness of the barrier layer depends linearly on the applied voltage. These observations are consistent with the predictions of the Point Defect Model, noting that the point defects within the barrier layer of the passive film are metal interstitials or oxygen vacancies, or both. No evidence for p-type behavior was obtained, indicating that cation vacancies do not have a significant population density in the film compared with the two donors (cation interstitials and oxygen vacancies).

  1. Effect of forming technique BixSiyOz coatings obtained by sol- gel and supported on 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Bautista Ruiz, J.; Olaya Flórez, J.; Aperador, W.

    2016-02-01

    BixSiyOz type coatings via sol-gel synthesized from bismuth nitrate pentahydrate, and tetraethyl orthosilicate as precursors; glacial acetic acid and 2-ethoxyethanol as solvents, and ethanolamine as complexing. The coatings were supported on AISI 316L stainless steel substrate through dip-coating and spin-coating techniques. The study showed that the spin-coating technique is efficient than dip-coating because it allows more dense and homogeneous films.

  2. Tritium and decay helium effects on the fracture toughness properties of types 316L, 304L and 21Cr-6Ni-9Mn stainless steels

    SciTech Connect

    Morgan, M.J.; Tosten, M.H

    1994-10-01

    J-integral fracture mechanics techniques and electron microscopy observations were used to investigate the effects of tritium and its radioactive decay product, {sup 3}He, on Types 316L, 304L and 21Cr-6Ni-9Mn stainless steels. Tritium-exposed-and-aged steels had lower fracture-toughness values and shallower sloped crack-growth-resistance curves than unexposed steels. Both fracture-toughness parameters decreased with increasing concentrations of {sup 3}He. The fracture-toughness reductions were accompanied by a change in fracture mode from microvoid-nucleation-and-growth processes in control samples to grain-and-twin-boundary fracture in tritium-charged-and-aged samples. Type 316L stainless steel had the highest fracture-toughness values and Type 21Cr-6Ni-9Mn had the lowest. Samples containing {sup 3}He but degassed of tritium had fracture toughness properties that were similar to uncharged samples. The results indicate that helium bubbles enhance the embrittlement effects of hydrogen by affecting the deformation properties and by increasing localized hydrogen concentrations through trapping effects.

  3. Effect of Heat Treatment on Low Temperature Toughness of Reduced Pressure Electron Beam Weld Metal of Type 316L Stainless Steel

    SciTech Connect

    Nakagawa, H.; Fujii, H.; Tamura, M.

    2006-03-31

    Austenitic stainless steels are considered to be the candidate materials for liquid hydrogen vessels and the related equipments, and those welding parts that require high toughness at cryogenic temperature. The authors have found that the weld metal of Type 316L stainless steel processed by reduced pressure electron beam (RPEB) welding has high toughness at cryogenic temperature, which is considered to be due to the single-pass welding process without reheating effect accompanied by multi-pass welding process.In this work, the effect of heat treatment on low temperature toughness of the RPEB weld metal of Type 316L was investigated by Charpy impact test at 77K. The absorbed energy decreased with higher temperature and longer holding time of heat treatment. The remarkable drop in the absorbed energy was found with heat treatment at 1073K for 2 hours, which is as low as that of conventional multi-pass weld metal such as tungsten inert gas welding. The observations of fracture surface and microstructure revealed that the decrease in the absorbed energy with heat treatment resulted from the precipitation of intermetallic compounds near delta-ferrite phase.

  4. Effect of Heat Treatment on Low Temperature Toughness of Reduced Pressure Electron Beam Weld Metal of Type 316L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Nakagawa, H.; Fujii, H.; Tamura, M.

    2006-03-01

    Austenitic stainless steels are considered to be the candidate materials for liquid hydrogen vessels and the related equipments, and those welding parts that require high toughness at cryogenic temperature. The authors have found that the weld metal of Type 316L stainless steel processed by reduced pressure electron beam (RPEB) welding has high toughness at cryogenic temperature, which is considered to be due to the single-pass welding process without reheating effect accompanied by multi-pass welding process. In this work, the effect of heat treatment on low temperature toughness of the RPEB weld metal of Type 316L was investigated by Charpy impact test at 77K. The absorbed energy decreased with higher temperature and longer holding time of heat treatment. The remarkable drop in the absorbed energy was found with heat treatment at 1073K for 2 hours, which is as low as that of conventional multi-pass weld metal such as tungsten inert gas welding. The observations of fracture surface and microstructure revealed that the decrease in the absorbed energy with heat treatment resulted from the precipitation of intermetallic compounds near delta-ferrite phase.

  5. Effect of Oxygen Content Upon the Microstructural and Mechanical Properties of Type 316L Austenitic Stainless Steel Manufactured by Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Cooper, Adam J.; Cooper, Norman I.; Dhers, Jean; Sherry, Andrew H.

    2016-09-01

    Although hot isostatic pressing (HIP) has been shown to demonstrate significant advances over more conventional manufacture routes, it is important to appreciate and quantify the detrimental effects of oxygen involvement during the HIP manufacture process on the microstructural and material properties of the resulting component. This paper quantifies the effects of oxygen content on the microstructure and Charpy impact properties of HIP'd austenitic stainless steel, through combination of detailed metallographic examination and mechanical testing on HIP'd Type 316L steel containing different concentrations (100 to 190 ppm) of oxygen. Micron-scale pores were visible in the microstructure of the HIP'd materials postmetallographic preparation, which result from the removal of nonmetallic oxide inclusions during metallographic preparation. The area fraction of the resulting pores is shown to correlate with the oxygen concentration which influences the Charpy impact toughness over the temperature range of 77 K to 573 K (-196 °C to 300 °C), and demonstrates the influence of oxygen involved during the HIP manufacture process on Charpy toughness. The same test procedures and microstructural analyses were performed on commercially available forged 316L. This showed comparatively fewer inclusions and exhibited higher Charpy impact toughness over the tested temperature range.

  6. Summary of recommended correlations for ITER-grade type 316L(N) for the ITER materials properties handbook

    SciTech Connect

    Billone, M.C.; Pawel, J.E.

    1996-04-01

    The focus of this effort is the effects of irradiation on the ultimate tensile strengths (UTS), the yield strength (YS), the uniform elongation (UE), the total elongation (TE) and the reduction in area (RA) in the ITER-relevant temperature range of 100-400{degrees}C. For the purpose of this summary, data for European heats of 316 with 0.020.08 wt.% are referred to as E316L(N) data and grouped together. Other heats of 316 and Ti-modified 316 are also included in the data base. For irradiation and postirradiation-test temperatures in the range of 200-400{degrees}C, the common behavior of these heats of stainless steel is a yield strength approaching the ultimate tensile strength approaching 800 MPa, a uniform elongation approaching 0.3%, a total elongation approaching 3-9%, and a high (about 60%) reduction in area as the neutron damage approaches 10 dpa.

  7. Fine structure analysis of biocompatible ceramic materials based hydroxyapatite and metallic biomaterials 316L

    NASA Astrophysics Data System (ADS)

    Anghelina, F. V.; Ungureanu, D. N.; Bratu, V.; Popescu, I. N.; Rusanescu, C. O.

    2013-11-01

    The aim of this paper was to obtain and characterize (surface morphology and fine structure) two types of materials: Ca10(PO4)6(OH)2 hydroxyapatite powder (HAp) as biocompatible ceramic materials and AISI 316L austenitic stainless steels as metallic biomaterials, which are the components of the metal-ceramic composites used for medical implants in reconstructive surgery and prosthetic treatment. The HAp was synthesized by coprecipitation method, heat treated at 200 °C, 800 °C and 1200 °C for 4 h, analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The stainless steel 316L type was made by casting, annealing and machined with a low speed (100 mm/s) in order to obtain a smooth surface and after that has been studied from residual stresses point of view in three polishing regimes conditions: at low speed polishing (150 rpm), at high speed polishing (1500 rpm) and high speed-vibration contact polishing (1500 rpm) using wide angle X-ray diffractions (WAXD). The chemical compositions of AISI 316 steel samples were measured using a Foundry Master Spectrometer equipped with CCD detector for spectral lines and the sparking spots of AISI 316L samples were analyzed using SEM. By XRD the phases of HAp powders have been identified and also the degree of crystallinity and average size of crystallites, and with SEM, we studied the morphology of the HAp. It has been found from XRD analysis that we obtained HAp with a high degree of crystallinity at 800 °C and 1200 °C, no presence of impurity and from SEM analysis we noticed the influence of heat treatment on the ceramic particles morphology. From the study of residual stress profiles of 316L samples were observed that it differs substantially for different machining regimes and from the SEM analysis of sparking spots we revealed the rough surfaces of stainless steel rods necessary for a better adhesion of HAp on it.

  8. The effect of synthetic scrubber solution chemistry on the corrosion behavior of type 316L stainless steel and Titanium Grade 2

    SciTech Connect

    Koch, G.H.; Beavers, J.A.; Whitman, L.

    1983-01-01

    A laboratory study was performed to investigate the effects of major solution variables of synthetic scrubber environments on the corrosion behavior of Type 316L Stainless Steel and Titanium Grade 2. The synthetic solution was calcium-based and contained magnesium, sodium, sulfate, chloride and fluoride. In solution preparation, it was found that the amount of sulfuric acid needed to achieve pH 1 was dependent on the chloride concentration. However, when the pH was adjusted to 1 prior to adding halides, the pH was found to decrease with increasing chloride concentration, whereas an increase in pH with increasing chloride concentration was observed when the initial pH was 4. When the pH was held constant, the corrosion rates of both the stainless steel and titanium decreased considerably with increasing chloride concentration above 30,000 ppm chloride. However, when the acid concentration was held constant, the corrosion rates of both alloys increased with increasing chloride concentration. Finally, corrosion rates decreased dramatically with increasing pH. An explanation of these observations is presented in terms of common ion effects and hydrogen ion activity.

  9. Effect of bicarbonate ion additives on pitting corrosion of type 316L stainless steel in aqueous 0.5 M sodium chloride solution

    SciTech Connect

    Park, J.J.; Pyun, S.I.; Lee, W.J.; Kim, H.P.

    1999-04-01

    The effect of bicarbonate ions (HCO{sub 3}{sup {minus}}) on pitting corrosion of type 316L stainless steel (SS, UNS S3 1603) was investigated in aqueous 0.5 M sodium chloride (NaCl) solution using potentiodynamic polarization, the abrading electrode technique, alternating current (AC) impedance spectroscopy combined with x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Addition of HCO{sub 3}{sup {minus}} ions to NaCl solutions extended the passive potential region in width and, at the same time, raised the pitting potential in value on the potentiodynamic polarization curve. Potentiostatic current transients obtained from the moment just after interrupting the abrading action showed the repassivation rate of propagating pits increased and that the pit growth rate decreased with increasing HCO{sub 3}{sup {minus}} ion concentration. Over the whole applied potential, the oxide film resistance was higher in the presence of HCO{sub 3}{sup {minus}} ions. The pit number density decreased with increasing HCO{sub 3}{sup {minus}} ion concentration. Moreover, addition of HCO{sub 3}{sup {minus}} ions to NaCl solutions retarded lateral pit growth, while promoting downward pit growth from the surface. The bare surface of the specimen repassivated preferentially along the pit mouth and walls, compared to the pit bottom, as a result of formation of a surface film with a high content of protective mixed ferrous-chromous carbonate ([Fe,Cr]CO{sub 3}) that formed from preferential adsorption of HCO{sub 3}{sup {minus}} ions.

  10. Effect of Surface Condition and Heat Treatment on Corrosion of Type 316L Stainless Steel in a Mercury Thermal Convection Loop

    SciTech Connect

    Pawel, S J

    2001-09-25

    Two thermal convection loops (TCLs) fabricated from 316L stainless steel and containing mercury and a variety of 316L coupons representing variable surface conditions and heat treatments have been operated continuously for 2000 h. Surface conditions included surface ground, polished, gold-coated, chemically etched, bombarded with Fe to simulate radiation damage, and oxidized. Heat treatments included solution treated, welded, and sensitized. In addition, a nitrogen doped 316L material, termed 316LN, was also examined in the solution treated condition. Duplicate TCLs were operated in this experiment--both were operated with a 305 C peak temperature, a 65 C temperature gradient, and mercury velocity of 1.2 m/min--but only one included a 36 h soak in Hg at 310 C just prior to operation to encourage wetting. Results indicate that the soak in Hg at 310 C had no lasting effect on wetting or compatibility with Hg. Further, based on examination of post-test wetting and coupon weight loss, only the gold-coated surfaces revealed significant interaction with Hg. In areas wetted significantly by Hg, the extreme surface of the stainless steel (ca 10 {micro}m) was depleted in Ni and Cr compared to the bulk composition.

  11. Effect of Surface Condition and Heat Treatment on Corrosion of Type 316L Stainless Steel in a Mercury Thermal Convection Loop

    SciTech Connect

    Pawel, S.J.

    2000-10-17

    Two thermal convection loops (TCLs) fabricated from 316L stainless steel and containing mercury and a variety of 316L coupons representing variable surface conditions and heat treatments have been operated continuously for 2000 h. Surface conditions included surface ground, polished, gold-coated, chemically etched, bombarded with Fe to simulate radiation damage, and oxidized. Heat treatments included solution treated, welded, and sensitized. In addition, a nitrogen doped 316L material, termed 316LN, was also examined in the solution treated condition. Duplicate TCLs were operated in this experiment--both were operated with a 305 C peak temperature, a 65 C temperature gradient, and mercury velocity of 1.2 m/min--but only one included a 36 h soak in Hg at 310 C just prior to operation to encourage wetting. Results indicate that the soak in Hg at 310 C had no lasting effect on wetting or compatibility with Hg. Further, based on examination of post-test wetting and coupon weight loss, only the gold-coated surfaces revealed significant interaction with Hg. In areas wetted significantly by Hg, the extreme surface of the stainless steel (ca 10 {micro}m) was depleted in Ni and Cr compared to the bulk composition.

  12. Mechanical and Electrochemical Characterization of Super-Solidus Sintered Austenitic Stainless Steel (316L)

    NASA Astrophysics Data System (ADS)

    Muthuchamy, A.; Raja Annamalai, A.; Ranka, Rishabh

    2016-08-01

    The present study compares the mechanical and electrochemical behaviour of austenitic (AISI 316L) stainless steel compacted at various pressures (200, 400 and 600 MPa) and conventionally sintered at super-solidus temperature of 1,400°C. The electrochemical behaviour was investigated in 0.1 N H2SO4 solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The shrinkage decreased and densification has been increased with increasing pressure. The mechanical and electrochemical behaviour with pressure has been correlated with densification response and microstructure (pore type, volume and morphology). Highest densification (~92% theoretical) achieved at 600 MPa (compaction pressure) and 1,400°C (sintering temperature) resulted in excellent combination of tensile strength and ductility (456 ± 40 MPa, 25 ± 1.1%), while showing excellent corrosion resistance (0.1 mmpy or 4.7 mpy).

  13. Damage mechanism at different transpassive potentials of solution-annealed 316 and 316l stainless steels

    NASA Astrophysics Data System (ADS)

    Morshed Behbahani, K.; Pakshir, M.; Abbasi, Z.; Najafisayar, P.

    2015-01-01

    Electrochemical impedance spectroscopy (EIS), anodic polarization and scanning electron microscopy techniques were used to investigate the damage mechanism in the transpassive potential region of AISI 316 and AISI 316L solution-annealed stainless steels (SS) with different degrees of sensitization. Depending on the DC potential applied during EIS tests, the AC responses in the transpassive region included three different regions: the first one associated with anodic dissolution of the passive layer, the second one contributed to the dissolution at the area near grain boundaries, and the last one attributed to pitting corrosion. In addition, the fitting results to experimental data showed that as the DC bias during the EIS test increases the charge transfer resistance ( R ct) decreases. Moreover, the R ct values decreased as the sensitization temperature increases but the AISI 316L SS samples exhibited a higher resistance to intergranular corrosion than 316 SS samples.

  14. Electrochemical behavior of the 316L steel type in a marine culture of microalgae (Porphyridium purpureum) under the 12/12 h photoperiod and effect of different working electrode exposure conditions on the biofilm-metal interface.

    PubMed

    Djemai-Zoghlache, Yamina; Isambert, Arsène; Belhaneche-Bensemra, Naima

    2011-12-01

    The industrial crops of microalgae use processes calling upon the presence of parts of metal nature such as steel 316L type. The goal of this study is to test the electrochemical behavior of this material in a marine culture of microalgae. Porphyridium purpureum was used under a photoperiod of alternation darkness/light 12/12 h, in order to apprehend the problems of biocorrosion involved in the biofouling. The evolution of the free potential of corrosion, according to the position of the samples and for different surface roughness, observations of the surface quality under the electron microscope with sweeping were carried out. The results showed that, overall, the strain P. purpureum does not have a corrosive effect on the 316L. The free potential of corrosion lies between -0.307 and -0.005 V(SCE). The adhesion of the cells seems stronger on the interface air/solid of the half-plunged sample with surface grit polished 1,000, confirmed by the presence of biofilm on the air part. The photoperiod acts on the evolution of the generated free potential of corrosion of the one 24-h period oscillation. Furthermore, the samples plunged horizontally lead to a stabilizing effect on the potential of free corrosion.

  15. Electrochemical properties of 316L stainless steel with culturing L929 fibroblasts

    PubMed Central

    Hiromoto, Sachiko; Hanawa, Takao

    2005-01-01

    Potentiodynamic polarization and impedance tests were carried out on 316L stainless steel with culturing murine fibroblast L929 cells to elucidate the corrosion behaviour of 316L steel with L929 cells and to understand the electrochemical interface between 316L steel and cells, respectively. Potential step test was carried out on 316L steel with type I collagen coating and culturing L929 cells to compare the effects of collagen and L929 cells. The open-circuit potential of 316L steel slightly shifted in a negative manner and passive current density increased with cells, indicating a decrease in the protective ability of passive oxide film. The pitting potential decreased with cells, indicating a decrease in the pitting corrosion resistance. In addition, a decrease in diffusivity at the interface was indicated from the decrease in the cathodic current density and the increase in the diffusion resistance parameter in the impedance test. The anodic peak current in the potential step test decreased with cells and collagen. Consequently, the corrosion resistance of 316L steel decreases with L929 cells. In addition, collagen coating would provide an environment for anodic reaction similar to that with culturing cells. PMID:16849246

  16. Hydrothermal calcium modification of 316L stainless steel and its apatite forming ability in simulated body fluid.

    PubMed

    Valanezahad, Alireza; Ishikawa, Kunio; Tsuru, Kanji; Maruta, Michito; Matsuya, Shigeki

    2011-01-01

    To understand the feasibility of calcium (Ca) modification of type 316L stainless steel (316L SS) surface using hydrothermal treatment, 316L SS plates were treated hydrothermally in calcium chloride (CaCl(2)) solution. X-ray photoelectron spectroscopic analysis revealed that the surface of 316L SS plate was modified with Ca after hydrothermal treatment at 200°C. And the immobilized Ca increased with CaCl(2) concentration. However no Ca-modification was occurred for 316L SS plates treated at 100°C. When Ca-modified 316L SS plate was immersed in simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma, low crystalline apatite was precipitated on its surface whereas no precipitate was observed on non Ca-modified 316L SS. The results obtained in the present study indicated that hydrothermal treatment at 200°C in CaCl(2) solution is useful for Ca-modification of 316L SS, and Ca-modification plays important role for apatite precipitation in SBF.

  17. In vitro biocompatibility of plasma-aided surface-modified 316L stainless steel for intracoronary stents.

    PubMed

    Bayram, Cem; Mizrak, Alpay Koray; Aktürk, Selçuk; Kurşaklioğlu, Hurkan; Iyisoy, Atila; Ifran, Ahmet; Denkbaş, Emir Baki

    2010-10-01

    316L-type stainless steel is a raw material mostly used for manufacturing metallic coronary stents. The purpose of this study was to examine the chemical, wettability, cytotoxic and haemocompatibility properties of 316L stainless steel stents which were modified by plasma polymerization. Six different polymeric compounds, polyethylene glycol, 2-hydroxyethyl methacrylate, ethylenediamine, acrylic acid, hexamethyldisilane and hexamethyldisiloxane, were used in a radio frequency glow discharge plasma polymerization system. As a model antiproliferative drug, mitomycin-C was chosen for covalent coupling onto the stent surface. Modified SS 316L stents were characterized by water contact angle measurements (goniometer) and x-ray photoelectron spectroscopy. C1s binding energies showed a good correlation with the literature. Haemocompatibility tests of coated SS 316L stents showed significant latency (t-test, p < 0.05) with respect to SS 316L and control groups in each test. PMID:20844318

  18. Localized corrosion of 316L stainless steel with SiO2-CaO films obtained by means of sol-gel treatment.

    PubMed

    Vallet-Regí, M; Izquierdo-Barba, I; Gil, F J

    2003-11-01

    Sol-gel films on austenitic stainless steel (AISI 316L) polished wafer were prepared from sono-sols obtained from tetraethylorthosilane and hydrated calcium nitrate. However, pitting was observed in different places on the stainless steel surfaces. The corrosion resistance was evaluated by the polarization resistance in simulated body fluid environment at 37 degrees C. The critical current density, the passive current density, the corrosion potential, and the critical pitting potential were studied. The austenitic stainless steel 316L treated presents important electrochemical corrosion and consequently its application as endosseous implants is not possible. PMID:14566812

  19. Étude expérimentale du comportement cyclique d'un acier du type 316 L sous chargement multiaxial complexe en traction-torsion-pressions interne et externe

    NASA Astrophysics Data System (ADS)

    Bocher, L.; Delobelle, P.

    1997-09-01

    are very rich in informations and lead to classify the different types of loading, with two or three cyclic components, with respect to the observed supplementary hardening. This classification was established as follows: i) The in-phase tests with two or three components (δ = \\varphi = 0^circ); no supplementary hardening is observed. ii) The tension-pressure tests such as r_1 = 1, \\varphi = 90^circ and r_1 = - 1, \\varphi = 60^circ, the hardening is slightly inferior to that of tension-torsion tests. iii) The tension-torsion tests such as r_2 = 1 and δ = 90^circ, where a substantial additionnal hardening takes place. iv) The tension-torsion-pressure tests where the three components are strongly shifted, namely: r_1 = r_2 = 1, δ = 90^circ and \\varphi = 60^circ, and r_2 = 1, r_1 = -1, δ = 41.4^circ and \\varphi = 82.8^circ. The hardening is slightly superior to the one recorded in tension-torsion. A more thorough study is in preparation which considers all the possible combinations in tension-torsion-pressures, and will be performed on the same material. The early results tend to validate the observations presented in this article. Cette étude réside dans la détermination expérimentale du comportement à la température ambiante de l'acier inoxydable 316 L sous chargement cyclique non proportionnel en traction-torsion-pressions interne et externe. Les deux ou trois déformations sinusoïdales appliquées sont soit en phase, soit hors-phase et l'on étudie l'amplitude du durcissement supplémentaire en fonction du degré de multiaxialité. On présente quelques boucles stabilisées typiques. Par rapport au durcissement supplémentaire maximal, les différents essais peuvent être classés comme suit: essais en phase (pas de durcissement supplémentaire), essais de traction-pressions hors-phase, essais de traction-torsion hors phase et essais de traction-torsion-pressions avec déphasages conséquents.

  20. Corrosive Metabolic Activity of Desulfovibrio sp. on 316L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Arkan, Simge; Ilhan-Sungur, Esra; Cansever, Nurhan

    2016-10-01

    The present study investigated the effects of chemical parameters (SO4 2-, PO4 3-, Cl-, pH) and the contents of extracellular polymeric substances (EPS) regarding the growth of Desulfovibrio sp. on the microbiologically induced corrosion of 316L stainless steel (SS). The experiments were carried out in laboratory-scaled test and control systems. 316L SS coupons were exposed to Desulfovibrio sp. culture over 720 h. The test coupons were removed at specific sampling times for enumeration of Desulfovibrio sp., determination of the corrosion rate by the weight loss measurement method and also for analysis of carbohydrate and protein in the EPS. The chemical parameters of the culture were also established. Biofilm/film formation and corrosion products on the 316L SS surfaces were investigated by scanning electron microscopy and energy-dispersive x-ray spectrometry analyses in the laboratory-scaled systems. It was found that Desulfovibrio sp. led to the corrosion of 316L SS. Both the amount of extracellular protein and chemical parameters (SO4 2- and PO4 3-) of the culture caused an increase in the corrosion of metal. There was a significantly positive relationship between the sessile and planktonic Desulfovibrio sp. counts (p < 0.01). It was detected that the growth phases of the sessile and planktonic Desulfovibrio sp. were different from each other and the growth phases of the sessile Desulfovibrio sp. vary depending on the subspecies of Desulfovibrio sp. and the type of metal when compared with the other published studies.

  1. Fabrication of antibacterial and hydrophilic electroless Ni-B coating on 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Bülbül, Ferhat; Bülbül, Leman Elif

    2016-01-01

    Biomaterial-associated bacterial infection is one of the most common complications with medical vehicles and implants made of stainless steel. A surface coating treatment like electroless Ni-B deposition, a new candidate to be used in a broad range of engineering applications owing to many advantages such as low cost, thickness uniformity, good wear resistance, may improve the antibacterial activity and physical properties of biomedical devices made of stainless steel. In this study, the antibacterial property of the electroless Ni-B film coated on AISI 316L (UNS S31603) stainless steel is basically investigated. Inhibition halo diameter measurement after incubation at 37 °C and 24 h demonstrates the existence of antimicrobial activity of the electroless Ni-B coating deposited on 316L stainless steel over the Escherichia coli test bacteria. The results of X-ray diffraction, scanning electron microscopy, atomic force microscopy and microhardness measurement studies confirms that the coating deposited on the substrate has an uniform amorphous and a harder structure. Besides, the wettability property of the uncoated substrate and the coating was measured as the contact angle of water. The water contact angle reduced about from 97.7 to 69.25°.

  2. Inhalation toxicity of 316L stainless steel powder in relation to bioaccessibility.

    PubMed

    Stockmann-Juvala, H; Hedberg, Y; Dhinsa, N K; Griffiths, D R; Brooks, P N; Zitting, A; Wallinder, I Odnevall; Santonen, T

    2013-11-01

    The Globally Harmonized System for Classification and Labelling of Chemicals (GHS) considers metallic alloys, such as nickel (Ni)-containing stainless steel (SS), as mixtures of substances, without considering that alloys behave differently compared to their constituent metals. This study presents an approach using metal release, explained by surface compositional data, for the prediction of inhalation toxicity of SS AISI 316L. The release of Ni into synthetic biological fluids is >1000-fold lower from the SS powder than from Ni metal, due to the chromium(III)-rich surface oxide of SS. Thus, it was hypothesized that the inhalation toxicity of SS is significantly lower than what could be predicted based on Ni metal content. A 28-day inhalation study with rats exposed to SS 316L powder (<4 µm, mass median aerodynamic diameter 2.5-3.0 µm) at concentrations up to 1.0 mg/L showed accumulation of metal particles in the lung lobes, but no signs of inflammation, although Ni metal caused lung toxicity in a similar published study at significantly lower concentrations. It was concluded that the bioaccessible (released) fraction, rather than the elemental nominal composition, predicts the toxicity of SS powder. The study provides a basis for an approach for future validation, standardization and risk assessment of metal alloys.

  3. Pitting and Intergranular Corrosion Resistance of AISI Type 301LN Stainless Steels

    NASA Astrophysics Data System (ADS)

    Ningshen, S.; Kamachi Mudali, U.

    2010-03-01

    The pitting and intergranular corrosion (IGC) resistance of AISI type 301LN stainless steels were evaluated using ASTM methods, anodic polarization, and electrochemical impedance techniques. The IGC results indicated that the microstructure of the samples after sensitization heat treatment at 675 °C for 1 h shows step or dual structure for both imported and indigenous materials indicating insignificant Cr23C6 precipitation. The results of immersion tests in boiling 6% copper sulfate + 16% sulfuric acid + copper solution for 24 h followed by the bend test (ASTM A262 Practice-E method) indicated no crack formation in any of the tested specimens. Pitting corrosion resistance carried out in 6% FeCl3 solution at different temperatures of 22 ± 2 and 50 ± 2 °C (ASTM G 48) up to the period of 72 h revealed pitting corrosion attack in all the investigated alloys. The potentiodynamic anodic polarization results in 0.5 M NaCl revealed variation in passive current density and pitting potential depending on the alloy chemistry and metallurgical condition. The passive film properties studied by electrochemical impedance spectroscopy (EIS) correlated well with the polarization results. The x-ray diffraction (XRD) results revealed the presence of austenite (γ) and martensite (α') phases depending on the material condition. The suitability of three indigenously developed AISI type 301LN stainless steels were compared with imported type 301LN stainless steel and the results are highlighted in this article.

  4. Upset welded 304L and 316L vessels for storage tests

    SciTech Connect

    Kanne, W.R. Jr.

    1996-04-01

    Two sets of vessels for tritium storage tests were fabricated using upset welding. A solid-state resistance upset weld was used to join the two halves of each vessel at the girth. The vessels differ from production reservoirs in design, material, and fabrication process. One set was made from forged 304L stainless steel and the other from forged 316L stainless steel. Six vessels of each type were loaded with a tritium mix in November 1995 and placed in storage at 71 C. This memo describes and documents the fabrication of the twelve vessels.

  5. Complexation- and ligand-induced metal release from 316L particles: importance of particle size and crystallographic structure.

    PubMed

    Hedberg, Yolanda; Hedberg, Jonas; Liu, Yi; Wallinder, Inger Odnevall

    2011-12-01

    Iron, chromium, nickel, and manganese released from gas-atomized AISI 316L stainless steel powders (sized <45 and <4 μm) were investigated in artificial lysosomal fluid (ALF, pH 4.5) and in solutions of its individual inorganic and organic components to determine its most aggressive component, elucidate synergistic effects, and assess release mechanisms, in dependence of surface changes using atomic absorption spectroscopy, Raman, XPS, and voltammetry. Complexation is the main reason for metal release from 316L particles immersed in ALF. Iron was mainly released, while manganese was preferentially released as a consequence of the reduction of manganese oxide on the surface. These processes resulted in highly complexing media in a partial oxidation of trivalent chromium to hexavalent chromium on the surface. The extent of metal release was partially controlled by surface properties (e.g., availability of elements on the surface and structure of the outermost surface) and partially by the complexation capacity of the different metals with the complexing agents of the different media. In general, compared to the coarse powder (<45 μm), the fine (<4 μm) powder displayed significantly higher released amounts of metals per surface area, increased with increased solution complexation capacity, while less amounts of metals were released into non-complexing solutions. Due to the ferritic structure of lower solubility for nickel of the fine powder, more nickel was released into all solutions compared with the coarser powder.

  6. Surface modification of investment cast-316L implants: microstructure effects.

    PubMed

    El-Hadad, Shimaa; Khalifa, Waleed; Nofal, Adel

    2015-03-01

    Artificial femur stem of 316L stainless steel was fabricated by investment casting using vacuum induction melting. Different surface treatments: mechanical polishing, thermal oxidation and immersion in alkaline solution were applied. Thicker hydroxyapatite (HAP) layer was formed in the furnace-oxidized samples as compared to the mechanically polished ones. The alkaline treatment enhanced the precipitation of HAP on the samples. It was also observed that the HAP precipitation responded differently to the different phases of the microstructure. The austenite phase was observed to have more homogeneous and smoother layer of HAP. In addition, the growth of HAP was sometimes favored on the austenite phase rather than on ferrite phase.

  7. Infrared Brazing of Ti50Ni50 Shape Memory Alloy and 316L Stainless Steel with Two Sliver-Based Fillers

    NASA Astrophysics Data System (ADS)

    Shiue, Ren-Kae; Chen, Chia-Pin; Wu, Shyi-Kaan

    2015-06-01

    Dissimilar infrared brazing Ti50Ni50 and AISI 316L stainless steel using two silver-based fillers, Cusil-ABA and Ticusil, was evaluated. The shear strength of the Ticusil brazed joint is higher than that of the Cusil-ABA brazed one due to the formation of better fillet. The maximum shear strength of 237 MPa is obtained for the Ticusil joint brazed at 1223 K (950 °C) for 60 seconds. The presence of interfacial Ti-Fe-(Cu) layer is detrimental to the shear strength of all joints.

  8. Gradient titanium and silver based carbon coatings deposited on AISI316L

    NASA Astrophysics Data System (ADS)

    Batory, Damian; Reczulska, Malgorzata Czerniak-; Kolodziejczyk, Lukasz; Szymanski, Witold

    2013-06-01

    The constantly growing market for medical implants and devices caused mainly due to a lack of proper attention attached to the physical condition as well as extreme sports and increased elderly population creates the need of new biocompatible biomaterials with controlled bioactivity and certain useful properties. According to many literature reports, regarding the modifications of variety of different biomaterials using the surface engineering techniques and their biological and physicochemical examination results, the most promising material for great spectra of medical applications seem to be carbon layers. Another issue is the interaction between the implant material and surrounding tissue. In particular cases this interface area is directly exposed to air. Abovementioned concern occurs mainly in case of the external fixations, thus they are more vulnerable to infection. Therefore a crucial role has the inhibition of bacterial adhesion that may prevent implant-associated infections, occurrence of other numerous complications and in particular cases rejection of the implant. For this reason additional features of carbon coatings like antibacterial properties seem to be desired and justified. Silver doped diamond-like carbon coatings with different Ag concentrations were prepared by hybrid RF PACVD/MS (Radio Frequency Plasma Assisted Chemical Vapor Deposition/Magnetron Sputtering) deposition technique. Physicochemical parameters like chemical composition, morphology and surface topography, hardness and adhesion were determined. Examined layers showed a uniform distribution of silver in the amorphous DLC matrix, high value of H/E ratio, good adhesion and beneficial topography which make them a perfect material for medical applications e.g. modification of implants for the external fixations.

  9. The structural and bio-corrosion barrier performance of Mg-substituted fluorapatite coating on 316L stainless steel human body implant

    NASA Astrophysics Data System (ADS)

    Sharifnabi, A.; Fathi, M. H.; Eftekhari Yekta, B.; Hossainalipour, M.

    2014-01-01

    In this study, Mg-substituted fluorapatite coatings were deposited on medical grade AISI 316L stainless steel via sol-gel dip coating method. Phase composition, crystallite size and degree of crystallinity of the obtained coatings were evaluated by X-ray diffraction (XRD) analysis. Fourier transform infrared (FTIR) spectroscopy was also used to evaluate functional groups of the obtained coatings. The surface morphology and cross-section of the final coatings were studied using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy was used to determine elemental chemical composition of the obtained coatings. In order to determine and compare the corrosion behavior of uncoated and Mg-substituted fluorapatite coated 316L stainless steel, electrochemical potentiodynamic polarization tests were performed in physiological solutions at 37 ± 1 °C. Moreover, the released metallic ions from uncoated and coated substrates were measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) within 2 months of immersing in Ringer's solution at 36.5 ± 1 °C as an indication of biocompatibility. The results showed that fluoride and magnesium were successfully incorporated into apatite lattice structure and the prepared coatings were nanostructured with crystallinity of about 70%. Obtained coatings were totally crack-free and uniform and led to decrease in corrosion current densities of 316L stainless steel in physiological solutions. In addition, coated sample released much less ions such as Fe, Cr and Ni in physiological media. Therefore, it was concluded that Mg-substituted fluorapatite coatings could improve the corrosion resistance and biocompatibility of 316L stainless steel human body implants.

  10. Corrosion protection performance of porous strontium hydroxyapatite coating on polypyrrole coated 316L stainless steel.

    PubMed

    Gopi, D; Ramya, S; Rajeswari, D; Kavitha, L

    2013-07-01

    Polypyrrole/strontium hydroxyapatite bilayer coatings were achieved on 316L stainless steel (316L SS) by the electropolymerisation of pyrrole from sodium salicylate solution followed by the electrodeposition of porous strontium hydroxyapatite. The formation and the morphology of the bilayer coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM), respectively. The corrosion resistance of the coated 316L SS specimens was investigated in Ringer's solution by electrochemical techniques and the results were substantiated with inductively coupled plasma atomic emission spectrometry (ICP-AES). The passive film underneath the polypyrrole layer is effective in protecting 316L SS against corrosion in Ringer's solution. Moreover, we believe that the top porous strontium hydroxyapatite layer can provide potential bioactivity to the 316L SS.

  11. Corrosion protection performance of porous strontium hydroxyapatite coating on polypyrrole coated 316L stainless steel.

    PubMed

    Gopi, D; Ramya, S; Rajeswari, D; Kavitha, L

    2013-07-01

    Polypyrrole/strontium hydroxyapatite bilayer coatings were achieved on 316L stainless steel (316L SS) by the electropolymerisation of pyrrole from sodium salicylate solution followed by the electrodeposition of porous strontium hydroxyapatite. The formation and the morphology of the bilayer coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM), respectively. The corrosion resistance of the coated 316L SS specimens was investigated in Ringer's solution by electrochemical techniques and the results were substantiated with inductively coupled plasma atomic emission spectrometry (ICP-AES). The passive film underneath the polypyrrole layer is effective in protecting 316L SS against corrosion in Ringer's solution. Moreover, we believe that the top porous strontium hydroxyapatite layer can provide potential bioactivity to the 316L SS. PMID:23475060

  12. Influence of grain size on ultrasonic spectral parameters in AISI type 316 stainless steel

    SciTech Connect

    Kumar, A.; Jayakumar, T.; Palanichamy, P.; Raj, B.

    1999-01-08

    The grain size of a material is an important engineering parameter which influences the mechanical properties such as fatigue, creep, yield strength, impact transition temperature, etc. The reliability of the ultrasonic methods for grain size measurement, particularly amplitude based measurements are highly dependent upon the couplant condition. Therefore, application of these methods may be difficult for some practical applications, where uniform couplant condition can not be maintained. Therefore, it would be useful if a simplified method is developed, which could be used on-line and is free from the above mentioned limitations of the other methods. The shift in the spectral peak frequency has been used for microstructural characterization in carbon steel and for evaluation of structural variations induced by tensile deformation in SUS304 stainless steel. The spectral peak frequency in SUS304 steel was found to increase with increase in the tensile elongation. This was attributed to formation and growth of martensite structures due to tensile deformation resulting in smaller crystalline grains, thus reducing the attenuation due to ultrasonic scattering. The peak frequency has also been found to shift with the change in the grain size in Inconel 600 and copper. In the present study, the shift in the spectral peak frequency and the change in full width at half maximum (FWHM) of the autopower spectrum are correlated with the grain size in AISI type 316 austenitic stainless steel, a widely used structural material in nuclear, chemical, fertilizer and many other industries.

  13. Intragranular cellular segregation network structure strengthening 316L stainless steel prepared by selective laser melting

    NASA Astrophysics Data System (ADS)

    Zhong, Yuan; Liu, Leifeng; Wikman, Stefan; Cui, Daqing; Shen, Zhijian

    2016-03-01

    A feasibility study was performed to fabricate ITER In-Vessel components by Selective Laser Melting (SLM) supported by Fusion for Energy (F4E). Almost fully dense 316L stainless steel (SS316L) components were prepared from gas-atomized powder and with optimized SLM processing parameters. Tensile tests and Charpy-V tests were carried out at 22 °C and 250 °C and the results showed that SLM SS316L fulfill the RCC-MR code. Microstructure characterization reveals the presence of hierarchical macro-, micro- and nano-structures in as-built samples that were very different from SS316L microstructures prepared by other established methods. The formation of a characteristic intragranular cellular segregation network microstructure appears to contribute to the increase of yield strength without losing ductility. Silicon oxide nano-inclusions were formed during the SLM process that generated a micro-hardness fluctuation in the building direction. The combined influence of a cellular microstructure and the nano-inclusions constraints the size of ductile dimples to nano-scale. The crack propagation is hindered by a pinning effect that improves the defect-tolerance of the SLM SS316L. This work proves that it was possible to manufacture SS316L with properties suitable for ITER First Wall panels. Further studies on irradiation properties of SLM SS316L and manufacturing of larger real-size components are needed.

  14. Microstructural characterization of an SA508–309L/308L–316L domestic dissimilar metal welded safe-end joint

    SciTech Connect

    Ming, Hongliang; Zhang, Zhiming; Wang, Jianqiu Han, En-Hou; Ke, Wei

    2014-11-15

    The microstructure of an SA508–309L/308L–316L domestic dissimilar metal welded safe-end joint was characterized in this work by optical microscopy, scanning electron microscopy (with electron back scattering diffraction) and micro-hardness testing. Epitaxial growth and competitive growth are evident in the 308L–316L fusion boundary regions. A martensite layer, carbon-depleted zones, and type-II and type-I boundaries are found in the SA508–309L fusion boundary regions, while only martensite and austenite mixed zones are observed in the SA508–308L fusion boundary regions. The microstructure near the fusion boundary and the microstructure transition in the SA508 heat affected zone are quite complex. Both for SA508–309L/308L and 308L–316L, the highest residual strain is located on the outside of the weldment. The residual strain and the grain boundary character distribution change with increasing distance from the fusion boundary in the heat affected zone of 316L. Micro-hardness measurements also reveal non-uniform mechanical properties across the weldment. - Highlights: • The microstructure of SA508 HAZ, especially near the FB, is very complex. • The outside of the dissimilar metal welded joint has the highest residual. • The micro-hardness distributions along the DMWJ are non-uniform.

  15. Effect of the La alloying addition on the antibacterial capability of 316L stainless steel.

    PubMed

    Yuan, J P; Li, W; Wang, C

    2013-01-01

    316L stainless steel is widely used for fashion jewelry but it can carry a large number of bacteria and cause the potential risk of infection since it has no antimicrobial ability. In this paper, La is used as an alloying addition. The antibacterial capability, corrosion resistance and processability of the La-modified 316L are investigated by microscopic observation, thin-film adhering quantitative bacteriostasis, electrochemical measurement and mechanical test. The investigations reveal that the La-containing 316L exhibits the Hormesis effect against Staphylococcus aureus ATCC 25923 and Escherichia coli DH5α, 0.05 wt.% La stimulates their growth, as La increases, the modified 316L exhibits the improved antibacterial effect. The more amount of La is added, the better antibacterial ability is achieved, and 0.42 wt.% La shows excellent antibacterial efficacy. No more than 0.11 wt.% La addition improves slightly the corrosion resistance in artificial sweat and has no observable impact on the processability of 316L, while a larger La content degrades them. Therefore, the addition of La alone in 316L is difficult to obtain the optimal combination of corrosion resistance, antibacterial capability and processability. In spite of that, 0.15 wt.% La around is inferred to be the trade-off for the best overall performance.

  16. Influence of flowing sodium on creep deformation and rupture behaviour of 316L(N) austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Ravi, S.; Laha, K.; Mathew, M. D.; Vijayaraghavan, S.; Shanmugavel, M.; Rajan, K. K.; Jayakumar, T.

    2012-08-01

    The influence of flowing sodium on creep deformation and rupture behaviour of AISI 316L(N) austenitic stainless steel has been investigated at 873 K over a stress range of 235-305 MPa. The results were compared with those obtained from testing in air environment. The steady state creep rates of the material were not influenced appreciably by the testing environments. The time to onset of tertiary stage of creep deformation was delayed in sodium environment. The creep-rupture lives of the material increased in sodium environment, which became more pronounced at lower applied stresses. The increase in rupture life of the material in flowing sodium was accompanied by an increase in rupture ductility. The creep damage on specimen surface as well as inside the specimen was less in specimen tested in sodium. SEM fractographic investigation revealed predominantly transgranular dimple failure for the specimen tested in sodium, whereas predominantly intergranular creep failure was observed in the air tested specimens. Almost no oxidation was observed in the specimens creep tested in the sodium environment. Absence of oxidation and less creep damage cavitation extended the secondary state in liquid sodium tests and lead to increase in creep rupture life and ductility of the material as compared to in air.

  17. Electrochemical and In Vitro Behavior of Nanostructure Sol-Gel Coated 316L Stainless Steel Incorporated with Rosemary Extract

    NASA Astrophysics Data System (ADS)

    Motalebi, Abolfazl; Nasr-Esfahani, Mojtaba

    2013-06-01

    The corrosion resistance of AISI 316L stainless steel for biomedical applications, was significantly enhanced by means of hybrid organic-inorganic sol-gel thin films deposited by spin-coating. Thin films of less than 100 nm with different hybrid characters were obtained by incorporating rosemary extract as green corrosion inhibitor. The morphology, composition, and adhesion of hybrid sol-gel coatings have been examined by SEM, EDX, and pull-off test, respectively. Addition of high additive concentrations (0.1%) did not disorganize the sol-gel network. Direct pull-off test recorded a mean coating-substrate bonding strength larger than 21.2 MPa for the hybrid sol-gel coating. The effect of rosemary extract, with various added concentrations from 0.012 to 0.1%, on the anticorrosion properties of sol-gel films have been characterized by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in simulated body fluid (SBF) solution and has been compared to the bare metal. Rosemary extract additions (0.05%) have significantly increased the corrosion protection of the sol-gel thin film to higher than 90%. The in vitro bioactivity of prepared films indicates that hydroxyapatite nuclei can form and grow on the surface of the doped sol-gel thin films. The present study shows that due to their excellent anticorrosion properties, bioactivity and bonding strength to substrate, doped sol-gel thin films are practical hybrid films in biomedical applications.

  18. Highly porous, low elastic modulus 316L stainless steel scaffold prepared by selective laser melting.

    PubMed

    Čapek, Jaroslav; Machová, Markéta; Fousová, Michaela; Kubásek, Jiří; Vojtěch, Dalibor; Fojt, Jaroslav; Jablonská, Eva; Lipov, Jan; Ruml, Tomáš

    2016-12-01

    Recently, porous metallic materials have been extensively studied as candidates for use in the fabrication of scaffolds and augmentations to repair trabecular bone defects, e.g. in surroundings of joint replacements. Fabricating these complex structures by using common approaches (e.g., casting and machining) is very challenging. Therefore, rapid prototyping techniques, such as selective laser melting (SLM), have been investigated for these applications. In this study, we characterized a highly porous (87 vol.%) 316L stainless steel scaffold prepared by SLM. 316L steel was chosen because it presents a biomaterial still widely used for fabrication of joint replacements and, from the practical point of view, use of the same material for fabrication of an augmentation and a joint replacement is beneficial for corrosion prevention. The results are compared to the reported properties of two representative nonporous 316L stainless steels prepared either by SLM or casting and subsequent hot forging. The microstructural and mechanical properties and the surface chemical composition and interaction with the cells were investigated. The studied material exhibited mechanical properties that were similar to those of trabecular bone (compressive modulus of elasticity ~0.15GPa, compressive yield strength ~3MPa) and cytocompatibility after one day that was similar to that of wrought 316L stainless steel, which is a commonly used biomaterial. Based on the obtained results, SLM is a suitable method for the fabrication of porous 316L stainless steel scaffolds with highly porous structures.

  19. Highly porous, low elastic modulus 316L stainless steel scaffold prepared by selective laser melting.

    PubMed

    Čapek, Jaroslav; Machová, Markéta; Fousová, Michaela; Kubásek, Jiří; Vojtěch, Dalibor; Fojt, Jaroslav; Jablonská, Eva; Lipov, Jan; Ruml, Tomáš

    2016-12-01

    Recently, porous metallic materials have been extensively studied as candidates for use in the fabrication of scaffolds and augmentations to repair trabecular bone defects, e.g. in surroundings of joint replacements. Fabricating these complex structures by using common approaches (e.g., casting and machining) is very challenging. Therefore, rapid prototyping techniques, such as selective laser melting (SLM), have been investigated for these applications. In this study, we characterized a highly porous (87 vol.%) 316L stainless steel scaffold prepared by SLM. 316L steel was chosen because it presents a biomaterial still widely used for fabrication of joint replacements and, from the practical point of view, use of the same material for fabrication of an augmentation and a joint replacement is beneficial for corrosion prevention. The results are compared to the reported properties of two representative nonporous 316L stainless steels prepared either by SLM or casting and subsequent hot forging. The microstructural and mechanical properties and the surface chemical composition and interaction with the cells were investigated. The studied material exhibited mechanical properties that were similar to those of trabecular bone (compressive modulus of elasticity ~0.15GPa, compressive yield strength ~3MPa) and cytocompatibility after one day that was similar to that of wrought 316L stainless steel, which is a commonly used biomaterial. Based on the obtained results, SLM is a suitable method for the fabrication of porous 316L stainless steel scaffolds with highly porous structures. PMID:27612756

  20. SCC crack growth rate of cold worked 316L stainless steel in PWR environment

    NASA Astrophysics Data System (ADS)

    Du, Donghai; Chen, Kai; Yu, Lun; lu, Hui; Zhang, Lefu; Shi, Xiuqiang; Xu, Xuelian

    2015-01-01

    Many component failures in nuclear power plants were found to be caused by stress corrosion cracking (SCC) of cold worked austenitic steels. Some of the pressure boundary component materials are even cold worked up to 35% plastic deformation, leaving high residual stress and inducing high growth rate of corrosion crack. Controlling water chemistry is one of the best counter measure to mitigate this problem. In this work, the effects of temperature (200 up to 325 °C) and dissolved oxygen (0 up to 2000 μg/L) on SCC crack growth rates of cold worked austenitic stainless steel type 316L have been tested by using direct current potential drop (DCPD) method. The results showed that temperature affected SCC crack growth rates more significantly in oxygenated water than in deaerated water. In argon deaerated water, the crack growth rate exhibited a peak at about 250 °C, which needs further verification. At 325 °C, the SCC crack growth rate increased rapidly with the increase of dissolved oxygen concentration within the range from 0 up to 200 μg/L, while when dissolved oxygen was above 200 μg/L, the crack growth rate followed a shallower dependence on dissolved oxygen concentration.

  1. The structural characterization of some biomaterials, type AISI 310, used in medicine

    NASA Astrophysics Data System (ADS)

    Minciuna, M. G.; Vizureanu, P.; Hanganu, C.; Achitei, D. C.; Popescu, D. C.; Focsaneanu, S. C.

    2016-06-01

    Orthopedics biomaterials are intended for implantation in the human body and substituted or help to repair of bones, cartilage or organ transplant, and tendons. At the end of the 20th century, the availability of materials for the manufacture implants used in medicine has been the same as for other industrial applications. The most used metals for manufacturing the orthopedics implants are: stainless steels, cobalt-chrome-molybdenum alloys, titanium and his alloys. The structural researches which are made in this paper, offer a complete analysis of AISI310 stainless steels, using: optical spectrometry, X-ray diffraction and scanning electronic microscopy.

  2. Re-weldability tests of irradiated 316L(N) stainless steel using laser welding technique

    NASA Astrophysics Data System (ADS)

    Yamada, Hirokazu; Kawamura, Hiroshi; Tsuchiya, Kunihiko; Kalinin, George; Kohno, Wataru; Morishima, Yasuo

    2002-12-01

    SS316L(N)-IG is the candidate material for the in-vessel and ex-vessel components of fusion reactors such as ITER (International Thermonuclear Experimental Reactor). This paper describes a study on re-weldability of un-irradiated and/or irradiated SS316L(N)-IG and the effect of helium generation on the mechanical properties of the weld joint. The laser welding process is used for re-welding of the water cooling branch pipeline repairs. It is clarified that re-welding of SS316L(N)-IG irradiated up to about 0.2 dpa (3.3 appm He) can be carried out without a serious deterioration of tensile properties due to helium accumulation. Therefore, repair of the ITER blanket cooling pipes can be performed by the laser welding process.

  3. Laser surface modification of 316 L stainless steel with bioactive hydroxyapatite.

    PubMed

    Balla, Vamsi Krishna; Das, Mitun; Bose, Sreyashree; Ram, G D Janaki; Manna, Indranil

    2013-12-01

    Laser-engineered net shaping (LENS™), a commercial additive manufacturing process, was used to modify the surfaces of 316 L stainless steel with bioactive hydroxyapatite (HAP). The modified surfaces were characterized in terms of their microstructure, hardness and apatite forming ability. The results showed that with increase in laser energy input from 32 J/mm(2) to 59 J/mm(2) the thickness of the modified surface increased from 222±12 μm to 355±6 μm, while the average surface hardness decreased marginally from 403±18 HV0.3 to 372±8 HV0.3. Microstructural studies showed that the modified surface consisted of austenite dendrites with HAP and some reaction products primarily occurring in the inter-dendritic regions. Finally, the surface-modified 316 L samples immersed in simulated body fluids showed significantly higher apatite precipitation compared to unmodified 316 L samples.

  4. Resistance of superhydrophobic and oleophobic surfaces to varied temperature applications on 316L SS

    NASA Astrophysics Data System (ADS)

    Shams, Hamza; Basit, Kanza; Saleem, Sajid; Siddiqui, Bilal A.

    316L SS also called Marine Stainless Steel is an important material for structural and marine applications. When superhydrophobic and oleophobic coatings are applied on 316L SS it shows significant resistance to wear and corrosion. This paper aims to validate the coatings manufacturer's information on optimal temperature range and test the viability of coating against multiple oil based cleaning agents. 316L SS was coated with multiple superhydrophic and oleohobic coatings and observed under SEM for validity of adhesion and thickness and then scanned under FFM to validate the tribological information. The samples were then dipped into multiple cleaning agents maintained at the range of operating temperatures specified by the manufacturer. Coating was observed for deterioration over a fixed time intervals through SEM and FFM. A comparison was drawn to validate the most critical cleaning agent and the most critical temperature at which the coating fails to leave the base substrate exposed to the environment.

  5. Evaluation of in-pile and out-of-pile stress relaxation in 316L stainless steel under uniaxial loading

    NASA Astrophysics Data System (ADS)

    Kaji, Yoshiyuki; Miwa, Yukio; Tsukada, Takashi; Kikuchi, Masahiko; Kita, Satoshi; Yonekawa, Minoru; Nakano, Junichi; Tsuji, Hirokazu; Nakajima, Hajime

    2002-12-01

    Stress relaxation of tensile type specimens under fast neutron irradiation at 288 °C has been studied for 316L stainless steel (SS) in the Japan Materials Testing Reactor. In-pile stress-relaxation tests were carried out at fast neutron fluence levels of 1.3×10 24, 5.5×10 24 and 1.5×10 25 n/m 2 ( E>1 MeV). These tests were carried out at the applied total strain levels of 0.06%, 0.1%, 0.3% and 0.75%. In order to evaluate the thermal stress-relaxation behavior and to distinguish it from the irradiation induced stress-relaxation behavior, out-of-pile stress-relaxation tests were also performed at 288 °C in air using an electric furnace. This paper describes results of in-pile and out-of-pile stress-relaxation tests on 316L SS tensile specimens. These results are compared with the literature data by Foster et al. [J. Nucl. Mater. 252 (1998) 89] which were mainly obtained from bend beam specimens. Moreover, these experimental results are compared with analytical results obtained using Nagakawa's model [J. Nucl. Mater. 212-215 (1994) 541].

  6. An evaluation of microbial growth and corrosion of 316L SS in glycol/seawater mixtures

    NASA Technical Reports Server (NTRS)

    Lee, Jason S.; Ray, Richard I.; Lowe, Kristine L.; Jones-Meehan, Joanne; Little, Brenda J.

    2003-01-01

    Glycol/seawater mixtures containing > 50% glycol inhibit corrosion of 316L stainless steel and do not support bacterial growth. The results indicate bacteria are able to use low concentrations of glycol (10%) as a growth medium, but bacterial growth decreased with increasing glycol concentration. Pitting potential, determined by anodic polarization, was used to evaluate susceptibility of 316L SS to corrosion in seawater-contaminated glycol. Mixture containing a minimum concentration of 50% propylene glycol-based coolant inhibited pitting corrosion. A slightly higher minimum concentration (55%) was needed for corrosion protection in ethylene glycol mixtures.

  7. Near surface chemistry and corrosion behavior of excimer laser surface-melted AISI type 304 stainless steel

    SciTech Connect

    Baer, D.R.; Frydrych, D.J.; Jervis, T.R.

    1988-05-01

    The effects of excimer laser surface melting on the near-surface chemistry, and corrosion behavior of AISI 304 stainless steel have been examined as a function of total energy deposited on the specimen. The surface chemistry resulting from the laser treatments has been examined using Auger electron spectroscopy. Electrochemical methods were used to monitor the corrosion behavior of the specimens in deaerated 0.1 M NaCl. Electron microscopy was used to characterize the extent of local corrosion of the specimens. Laser treatment was observed to increase the chromium concentration of the surface oxide and to reduce the number of pits. Two types of pits were observed on untreated material, but only one type of pit occurred after laser treatment. 7 refs., 5 figs.

  8. Application of strainrange partitioning to the prediction of creep-fatigue lives of AISI types 304 and 316 stainless steel

    NASA Technical Reports Server (NTRS)

    Saltsman, J. F.; Halford, G. R.

    1976-01-01

    As a demonstration of the predictive capabilities of the method of Strainrange Partitioning, published high-temperature, low cycle, creep-fatigue test results on AISI Types 304 and 316 stainless steel were analyzed and calculated, cyclic lives compared with observed lives. Predicted lives agreed with observed lives within factors of two for 76 percent, factors of three for 93 percent, and factors of four for 98 percent of the laboratory tests analyzed. Agreement between observed and predicted lives is judged satisfactory considering that the data are associated with a number of variables (two alloys, several heats and heat treatments, a range of temperatures, different testing techniques, etc.) that are not directly accounted for in the calculations.

  9. Application of Strainrange Partitioning to the prediction of creep-fatigue lives of AISI Types 304 and 316 stainless steel

    NASA Technical Reports Server (NTRS)

    Saltsman, J. F.; Halford, G. R.

    1977-01-01

    As a demonstration of the predictive capabilities of the method of Strainrange Partitioning, published high-temperature, low cycle, creep-fatigue test results on AISI Types 304 and 316 stainless steel were analyzed and calculated cyclic lives compared with observed lives. Predicted lives agreed with observed lives within factors of two for 76 percent, factors of three for 93 percent, and factors of four for 98 percent of the laboratory tests analyzed. Agreement between observed and predicted lives is judged satisfactory considering that the data are associated with a number of variables (two alloys, several heats and heat treatments, a range of temperatures, different testing techniques, etc.) that are not directly accounted for in the calculations.

  10. Development of nanostructured SUS316L-2%TiC with superior tensile properties

    NASA Astrophysics Data System (ADS)

    Sakamoto, T.; Kurishita, H.; Matsuo, S.; Arakawa, H.; Takahashi, S.; Tsuchida, M.; Kobayashi, S.; Nakai, K.; Terasawa, M.; Yamasaki, T.; Kawai, M.

    2015-11-01

    Structural materials used in radiation environments require radiation tolerance and sufficient mechanical properties in the controlled state. In order to offer SUS316L austenitic stainless steel with the assumed requirements, nanostructured SUS316L with TiC addition of 2% (SUS316L-2TiC) that is capable of exhibiting enhanced tensile ductility and flow strength sufficient for structural applications was fabricated by advanced powder metallurgical methods. The methods include MA (Mechanical Alloying), HIP (Hot Isostatic Pressing), GSMM (Grain boundary Sliding Microstructural Modification) for ductility enhancement, cold rolling at temperatures below Md (the temperature where the martensite phase occurs by plastic deformation) for phase transformation from austenite to martensite and heat treatment for reverse transformation from martensite to austenite. It is shown that the developed SUS316L-2TiC exhibits ultrafine grains with sizes of 90-270 nm, accompanied by TiC precipitates with 20-50 nm in grain interior and 70-110 nm at grain boundaries, yield strengths of 1850 to 900 MPa, tensile strengths of 1920 to 1100 MPa and uniform elongations of 0.6-21%, respectively, depending on the heat treatment temperature after rolling at -196 °C.

  11. Microstructure and Corrosion Resistance of Laser Additively Manufactured 316L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Trelewicz, Jason R.; Halada, Gary P.; Donaldson, Olivia K.; Manogharan, Guha

    2016-03-01

    Additive manufacturing (AM) of metal alloys to produce complex part designs via powder bed fusion methods such as laser melting promises to be a transformative technology for advanced materials processing. However, effective implementation of AM processes requires a clear understanding of the processing-structure-properties-performance relationships in fabricated components. In this study, we report on the formation of micro and nanoscale structures in 316L stainless steel samples printed by laser AM and their implications for general corrosion resistance. A variety of techniques including x-ray diffraction, optical, scanning and transmission electron microscopy, x-ray fluorescence, and energy dispersive x-ray spectroscopy were employed to characterize the microstructure and chemistry of the laser additively manufactured 316L stainless steel, which are compared with wrought 316L coupons via electrochemical polarization. Apparent segregation of Mo has been found to contribute to a loss of passivity and an increased anodic current density. While porosity will also likely impact the environmental performance (e.g., facilitating crevice corrosion) of AM alloys, this work demonstrates the critical influence of microstructure and heterogeneous solute distributions on the corrosion resistance of laser additively manufactured 316L stainless steel.

  12. Structure and Long-Term Stability of Alkylphosphonic Acid Monolayers on SS316L Stainless Steel.

    PubMed

    Kosian, Medea; Smulders, Maarten M J; Zuilhof, Han

    2016-02-01

    Surface modification of stainless steel (SS316L) to improve surface properties or durability is an important avenue of research, as SS316L is widely used in industry and science. We studied, therefore, the formation and stability of a series of organic monolayers on SS316L under industrially relevant conditions. These included acidic (pH 3), basic (pH 11), neutral (Milli-Q water), and physiological conditions [10 mM phosphate-buffered saline (PBS)], as well as dry heating (120 °C). SS316L was modified with alkylphosphonic acids of chain length (CH2)n with n varying between 3 and 18. While alkylphosphonic acids of all chain lengths formed self-assembled monolayers with hydrophobic properties, only monolayers of chain lengths 12-18 formed ordered monolayers, as evidenced by static water contact angle (SCA), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and infrared reflection absorption spectroscopy (IRRAS). A long-term stability study revealed the excellent stability of monolayers with chain lengths 12-18 for up to 30 days in acid, neutral, and physiological solutions, and for up to 7 days under dry heating. Under strong basic conditions a partial breakdown of the monolayer was observed, especially for the shorter chain lengths. Finally, the effect of multivalent surface attachment on monolayer stability was explored by means of a series of divalent bisphosphonic acids. PMID:26771302

  13. [Corrosion of stainless steel 201, 304 and 316L in the simulated sewage pipes reactor].

    PubMed

    Bao, Guo-Dong; Zuo, Jian-E; Wang, Ya-Jiao; Gan, Li-Li

    2014-08-01

    The corrosion behavior of stainless steel 201, 304 and 316L which would be used as sewer in-situ rehabilitation materials was studied in the simulated sewage pipes reactor. The corrosion potential and corrosion rate of these three materials were studied by potentiodynamic method on the 7th, 14th, 21st, 56th day under two different conditions which were full immersion condition or batch immersion condition with a 2-day cycle. The electrode process was studied by Electrochemical Impedance Spectroscopy (EIS) on the 56th day. The microstructure and composition of the corrosion pitting were analyzed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS) on the 56th day. The results showed that 304 and 316L had much better corrosion resistance than 201 under both conditions. 304 and 316L had much smaller corrosion rate than 201 under both conditions. The corrosion resistance of all three kinds of stainless steel under the batch immersion condition was much better than those under the full immersion condition. The corrosion rate of all three kinds of stainless steel under the batch immersion condition was much smaller than those under the full immersion condition. Point pitting corrosion was formed on the surfaces of 304 and 316L. In comparison, a large area of corrosion was formed in the surface of 201.

  14. Microstructural examination of the effect of surface machining on stress corrosion cracking in core shroud made of 316L

    SciTech Connect

    Sueishi, Y.; Kohyama, A.; Narui, M.; Asano, K.

    2006-07-01

    Cracks exhibited on the hardened surface region of the boiling water reactor (BWR) core shroud made of 316L were examined. The sample was removed from the circumference ring of a commercial power plant after about 9 years in service. On the surface with mechanical milling followed by grinding during the manufacturing process, micro-crack was found to propagate nearly perpendicular to the grinding direction. Cross-sectional transmission electron microscopy (TEM) observation of the micro-crack indicates that the crack has been initiated along the boundary of [111[<112> type deformation twins and the shear bands in Goss position [110]<001>. Along the crack wall, the Cr-Fe spinel and the grained magnetite were identified in inner and outer layer of the oxide thin film, respectively. The results suggest one potential mechanism of the cracking that the heavily deformed structure by surface machining is the origin or the factor for acceleration of the cracking. (authors)

  15. Pitting corrosion behavior of 316L stainless steels in tropical seawater

    SciTech Connect

    Zaragoza-Ayala, A.E.; Acuna, N.; Solis, W.; Aldana, J.; Festy, D.

    1996-10-01

    The open circuit potential (OCP) and the pitting potential of 316L stainless steel (SS) have been determined as a function of the immersion time in tropical seawater. An increase in the noble direction of the OCP for short exposures was observed. After certain time occasional fall and rise of the OCP values was observed. Pitting potentials measurements shows that a relatively small increase in the seawater temperature can increase the susceptibility to localized corrosion of this alloy. Little or no effect of the exposure time on the pitting potential was observed. SEM observation shows that the steel surface was colonized by bacteria an microalgae which forms an heterogeneous biofilm on the steel surface which probably have an influence on the corrosion behavior of 316 L SS in seawater.

  16. Improving endothelialization on 316L stainless steel through wettability controllable coating by sol-gel technology

    NASA Astrophysics Data System (ADS)

    Wang, Mingqi; Wang, Yao; Chen, Yijie; Gu, Hongchen

    2013-03-01

    Rapid endothelialization by surface coverage is considered as a way to increase blood compatibility of the vascular stent and reduce smooth muscle cell (SMC) mediated restenosis. Coatings on 316L stainless steels with different wettabilities and similar topographies were obtained through sol-gel process by regulating the proportions of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES). Adhesion and proliferation of vascular endothelial cells (EC) and SMC on these substrates have been evaluated by cell numbers, cell morphology, and expression of cytoskeletal protein. Results showed that EC and SMC responded differently to the coated surfaces. Enhanced endothelialization of bare 316L was found at the moderately hydrophilic coating (contact angle 45.3°) which exhibited effective inhibition of SMC and negligible influence on EC. These results are expected to lay foundation for the solution of the vascular restenosis which was mainly derived from the hyperplasia of SMC.

  17. Creep rupture strength of activated-TIG welded 316L(N) stainless steel

    NASA Astrophysics Data System (ADS)

    Sakthivel, T.; Vasudevan, M.; Laha, K.; Parameswaran, P.; Chandravathi, K. S.; Mathew, M. D.; Bhaduri, A. K.

    2011-06-01

    316L(N) stainless steel plates were joined using activated-tungsten inert gas (A-TIG) welding and conventional TIG welding process. Creep rupture behavior of 316L(N) base metal, and weld joints made by A-TIG and conventional TIG welding process were investigated at 923 K over a stress range of 160-280 MPa. Creep test results showed that the enhancement in creep rupture strength of weld joint fabricated by A-TIG welding process over conventional TIG welding process. Both the weld joints fractured in the weld metal. Microstructural observation showed lower δ-ferrite content, alignment of columnar grain with δ-ferrite along applied stress direction and less strength disparity between columnar and equiaxed grains of weld metal in A-TIG joint than in MP-TIG joint. These had been attributed to initiate less creep cavitation in weld metal of A-TIG joint leading to improvement in creep rupture strength.

  18. Evaluation of the soft tissue biocompatibility of MgCa0.8 and surgical steel 316L in vivo: a comparative study in rabbits

    PubMed Central

    2010-01-01

    Background Recent studies have shown the potential suitability of magnesium alloys as biodegradable implants. The aim of the present study was to compare the soft tissue biocompatibility of MgCa0.8 and commonly used surgical steel in vivo. Methods A biodegradable magnesium calcium alloy (MgCa0.8) and surgical steel (S316L), as a control, were investigated. Screws of identical geometrical conformation were implanted into the tibiae of 40 rabbits for a postoperative follow up of two, four, six and eight weeks. The tibialis cranialis muscle was in direct vicinity of the screw head and thus embedded in paraffin and histologically and immunohistochemically assessed. Haematoxylin and eosin staining was performed to identify macrophages, giant cells and heterophil granulocytes as well as the extent of tissue fibrosis and necrosis. Mouse anti-CD79α and rat anti-CD3 monoclonal primary antibodies were used for B- and T-lymphocyte detection. Evaluation of all sections was performed by applying a semi-quantitative score. Results Clinically, both implant materials were tolerated well. Histology revealed that a layer of fibrous tissue had formed between implant and overlying muscle in MgCa0.8 and S316L, which was demarcated by a layer of synoviocyte-like cells at its interface to the implant. In MgCa0.8 implants cavities were detected within the fibrous tissue, which were surrounded by the same kind of cell type. The thickness of the fibrous layer and the amount of tissue necrosis and cellular infiltrations gradually decreased in S316L. In contrast, a decrease could only be noted in the first weeks of implantation in MgCa0.8, whereas parameters were increasing again at the end of the observation period. B-lymphocytes were found more often in MgCa0.8 indicating humoral immunity and the presence of soluble antigens. Conversely, S316L displayed a higher quantity of T-lymphocytes. Conclusions Moderate inflammation was detected in both implant materials and resolved to a minimum

  19. Microstructure of Au-ion irradiated 316L and FeNiCr austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Jublot-Leclerc, S.; Li, X.; Legras, L.; Lescoat, M.-L.; Fortuna, F.; Gentils, A.

    2016-11-01

    Thin foils of 316L were irradiated in situ in a Transmission Electron Microscope with 4 MeV Au ions at 450 °C and 550 °C. Similar irradiations were performed at 450 °C in FeNiCr. The void and dislocation microstructure of 316L is found to depend strongly on temperature. At 450 °C, a dense network of dislocation lines is observed in situ to grow from black dot defects by absorption of other black dots and interstitial clusters whilst no Frank loops are detected. At 550 °C, no such network is observed but large Frank loops and perfect loops whose sudden appearance is concomitant with a strong increase in void density as a result of a strong coupling between voids and dislocations. Moreover, differences in both alloys microstructure show the major role played by the minor constituents of 316L, increasing the stacking fault formation energy, and possibly leading to significant differences in swelling behaviour.

  20. Laser-driven shock waves to improve the corrosion properties of 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Peyre, Patrice; Berthe, Laurent; Fabbro, Remy; Carboni, Christelle; Bartnicki, Eric; Beranger, Gerard; Lemaitre, Christian

    1999-06-01

    Different laser pulses ranging between 0.6 and 10 ns were used to generate up to 10 GPa amplitude shock waves in an aluminum-coated 316L stainless steel with application to modify its surface behavior, especially its pitting corrosion behavior in NaCl 30g/l medium. Laser shock waves (LSW) characterizations (Hugoniot limits, Shock wave attenuations) were carried out with a VISAR system and compared with 1D simulations using Shylac Lagrangian code. Treated surfaces were analyzed through chemical spectroscopies (GDS, XPS), metallurgical characterizations (deformation bands, twins...) and residual stress measurements. Laser-induced surface modifications were also compared with the classical effects of a shot-peening at high coverage rate. Lastly, rest potential recordings, anodic polarization tests and statistical treatments of the pitting potentials were carried out to estimate the influence of a laser peening on the pitting corrosion resistance of a passive 316L alloy. It was clearly demonstrated that LSW could improve the corrosion behavior of 316L by pure mechanical effects such as compressive residual stresses which tend to reduce the nocivity of surface inclusions.

  1. Investigation on 316L/W functionally graded materials fabricated by mechanical alloying and spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Tan, Chao; Wang, Guoyu; Ji, Lina; Tong, Yangang; Duan, Xuan-Ming

    2016-02-01

    316L-W (Tungsten) composite materials were fabricated by spark plasma sintering (SPS) of mechanically alloyed 316L-W powders for the development of functionally graded materials (FGMs). The effect of milling parameters on the morphology of the blended 316L/W powders and its subsequent effect on the transition between 316L and W particles during the SPS process were investigated. Samples were characterized by SEM, EDS and XRD analyses. The results so obtained show that with the increase of milling time, the mechanically activated W powder particles become thinner and smoother, with some broken fragments aggregated or inserted in the severely deformed 316L particles. A further SPS process under the conditions of 1050 °C × 45.5 MPa × 5 min leads to the densification of the powder compact and the formation of a distinguishable gray belt surrounding the retained W particles. Such a belt, which has a width of about 2-8 μm depending on different milling parameters and mainly contains Fe7W6, Fe3W3C and Fe2W phases, is bound to be a transitional region between the retained W particles and the 316L matrix. This favorable behavior with regards to the formation of a transitional belt, is accompanied by a substantial increase in the hardness values of the composite.

  2. 316L stainless steel tubes corrosion influenced by SRB in sea water

    SciTech Connect

    Yoffe, P.

    1997-08-01

    A tube made from SS316L was attacked by stagnated sea water. The typical onion form of the pits were obscured in welded and unwelded sectors of the tube. Iron sulfides FeS{sub 1{minus}x} and FeS{sub 2} (in pyrite form) were observed on effected surface of the tube, in addition to iron chloride and oxide/hydroxide. Theoretical investigation was based on cluster model of alloy and thermodynamic/kinetic characterization of possible reactions. It was concluded that microbially influenced sulfidizing played an accelerating role in the failure that exhibited the typical characteristics for stagnated sea water effect to chromium-nickel stainless steel.

  3. Effect of Post-Weld Heat Treatment on Mechanical and Electrochemical Properties of Gas Metal Arc-Welded 316L (X2CrNiMo 17-13-2) Stainless Steel

    NASA Astrophysics Data System (ADS)

    Muhammad, F.; Ahmad, A.; Farooq, A.; Haider, W.

    2016-08-01

    In the present research work, corrosion behavior of post-weld heat-treated (PWHT) AISI 316L (X2CrNiMo 17-13-2) specimens joined by gas metal arc welding is compared with as-welded samples by using potentiodynamic polarization technique. Welded samples were PWHT at 1323 K for 480 s and quenched. Mechanical properties, corrosion behavior and microstructures of as-welded and PWHT specimens were investigated. Microstructural studies have shown grain size refinement after PWHT. Ultimate tensile strength and yield strength were found maximum for PWHT samples. Bend test have shown that PWHT imparted ductility in welded sample. Fractographic analysis has evidenced ductile behavior for samples. Potentiodynamic polarization test was carried out in a solution composed of 1 M H2SO4 and 1 N NaCl. Corrosion rate of weld region was 127.6 mpy, but after PWHT, it was decreased to 13.12 mpy.

  4. Effect of Post-Weld Heat Treatment on Mechanical and Electrochemical Properties of Gas Metal Arc-Welded 316L (X2CrNiMo 17-13-2) Stainless Steel

    NASA Astrophysics Data System (ADS)

    Muhammad, F.; Ahmad, A.; Farooq, A.; Haider, W.

    2016-10-01

    In the present research work, corrosion behavior of post-weld heat-treated (PWHT) AISI 316L (X2CrNiMo 17-13-2) specimens joined by gas metal arc welding is compared with as-welded samples by using potentiodynamic polarization technique. Welded samples were PWHT at 1323 K for 480 s and quenched. Mechanical properties, corrosion behavior and microstructures of as-welded and PWHT specimens were investigated. Microstructural studies have shown grain size refinement after PWHT. Ultimate tensile strength and yield strength were found maximum for PWHT samples. Bend test have shown that PWHT imparted ductility in welded sample. Fractographic analysis has evidenced ductile behavior for samples. Potentiodynamic polarization test was carried out in a solution composed of 1 M H2SO4 and 1 N NaCl. Corrosion rate of weld region was 127.6 mpy, but after PWHT, it was decreased to 13.12 mpy.

  5. Mechanical and physical behavior of newly developed functionally graded materials and composites of stainless steel 316L with calcium silicate and hydroxyapatite.

    PubMed

    Ataollahi Oshkour, Azim; Pramanik, Sumit; Mehrali, Mehdi; Yau, Yat Huang; Tarlochan, Faris; Abu Osman, Noor Azuan

    2015-09-01

    This study aimed to investigate the structural, physical and mechanical behavior of composites and functionally graded materials (FGMs) made of stainless steel (SS-316L)/hydroxyapatite (HA) and SS-316L/calcium silicate (CS) employing powder metallurgical solid state sintering. The structural analysis using X-ray diffraction showed that the sintering at high temperature led to the reaction between compounds of the SS-316L and HA, while SS-316L and CS remained intact during the sintering process in composites of SS-316L/CS. A dimensional expansion was found in the composites made of 40 and 50 wt% HA. The minimum shrinkage was emerged in 50 wt% CS composite, while the maximum shrinkage was revealed in samples with pure SS-316L, HA and CS. Compressive mechanical properties of SS-316L/HA decreased sharply with increasing of HA content up to 20 wt% and gradually with CS content up to 50 wt% for SS-316L/CS composites. The mechanical properties of the FGM of SS-316L/HA dropped with increase in temperature, while it was improved for the FGM of SS-316L/CS with temperature enhancement. It has been found that the FGMs emerged a better compressive mechanical properties compared to both the composite systems. Therefore, the SS-316L/CS composites and their FGMs have superior compressive mechanical properties to the SS-316L/HA composites and their FGMs and also the newly developed FGMs of SS-316L/CS with improved mechanical and enhanced gradation in physical and structural properties can potentially be utilized in the components with load-bearing application.

  6. Simulations of spall experiments in 316L stainless steel conducted with square and triangular waves

    NASA Astrophysics Data System (ADS)

    Seaman, Lynn; Gray, G. T.(Rusty), III

    2005-07-01

    Triangular stress waves are more like those from applications (laser, explosives, nuclear) but laboratory experiments for studying spall damage generally provide square-topped waves. Gray et al (2003) performed four impact experiments in 316L stainless steel, two with square waves and two with triangular, achieving void damage in all but the lower-stress (6.6 GPa) triangular-wave sample. Simulations with the nucleation-and-growth model DFRACT exhibit fair correspondence with the damage in those tests showing damage, but also indicate damage in the triangular-wave test showing no damage. We are examining mechanisms which may delay the initiation of void damage or otherwise alter the expected damage processes in the model. Reference: G.T. (Rusty) Gray III, N. K. Bourne, B.L. Henrie, and J.C.F. Millet, Influence of Shock-Wave Profile Shape (Triangular ``Taylor-Wave'' versus Square-Topped) on the Spallation Response of 316L Stainless Steel, J. Phys. IV France 110 (2003), page 773-778,

  7. Hydrogen transport and solubility in 316L and 1.4914 steels for fusion reactor applications

    NASA Astrophysics Data System (ADS)

    Forcey, K. S.; Ross, D. K.; Simpson, J. C. B.; Evans, D. S.

    1988-12-01

    Equations are given which describe the permeation rate, diffusivity and solubility of hydrogen over the range 250-600°C at pressures up to 10 5Pa for the 316L stainless and modified 1.4914 martensitic candidate steels proposed for the construction of the Next European Torus (NET). For heat-treated 316L steel, the permeation rates measured agreed well with previous work and did not vary significantly from specimen to specimen or from batch to batch. Measurements of the permeation rate of hydrogen and deuterium through the modified 1.4914 steel, believed to be the first made, show that the martensitic steel is significantly more permeable than the austenitic steel, by an order of magnitude at 250°C and a factor of five at 600°C. This difference could make it necessary to use permeation barriers on critical components made from the martensitic steel in order to reduce the tritium permeation rate to acceptable levels.

  8. The effect of surface roughness on the fretting corrosion of 316L stainless steel biomaterial surfaces

    NASA Astrophysics Data System (ADS)

    Shenoy, Aarti

    The medical device industry is still seeking answers to the mechanically-assisted corrosion (MAC) problem, which becomes increasingly important due to modularity in design. MAC manifests in various forms, some of which are fretting corrosion, crevice corrosion and stress corrosion. Several studies have been conducted to understand the causes and the factors that affect fretting corrosion. Some of the factors are the applied load, surface potential, oxide film characteristics and solution chemistry near the interface. Surface properties such as surface roughness determine the topography of the surface and the nature of asperity-asperity contact, which is a factor that would determine the mechanically assisted corrosion behavior of the interface, like the stem-neck and head-neck taper junctions in modular hip replacement devices. This study aims to understand the correlation between surface roughness of 316L stainless steel samples and fretting corrosion behavior using a variable load pin-on-disc test. It was found that the smoother surfaces are associated with lower fretting currents. However, smoother surfaces also created the conditions for fretting initiated crevice corrosion to occur more readily. Fretting corrosion regimes and the severity are thus dependent upon the surface roughness. A possible explanation could be due to the inverse relationship between the interasperity distance parameter, Delta, and fretting currents. The coefficient of friction between the two surfaces in contact however remained unaffected by surface roughness, but decreased with increasing load. Smoother surfaces, while lowering fretting corrosion reactions can enhance crevice corrosion reactions in 316L stainless steel interfaces.

  9. Strain rate dependence of impact properties of sintered 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Lee, Woei-Shyan; Lin, Chi-Feng; Liu, Tsung-Ju

    2006-12-01

    This paper uses a material testing system (MTS) and a compressive split-Hopkinson bar to investigate the impact behaviour of sintered 316L stainless steel at strain rates ranging from 10 -3 s -1 to 7.5 × 10 3 s -1. It is found that the true stress, the rate of work hardening and the strain rate sensitivity vary significantly as the strain rate increases. The flow behaviour of the sintered 316L stainless steel can be accurately predicted using a constitutive law based on Gurson's yield criterion and the flow rule proposed by Khan, Huang and Liang (KHL). Microstructural observations reveal that the degree of localized grain deformation increases, but the pore density and the grain size decrease, with increasing strain rate. Adiabatic shear bands associated with cracking are developed at strain rates higher than 5.6 × 10 3 s -1. The fracture surfaces exhibit ductile dimples. The depth and density of these dimples decrease with increasing strain rate.

  10. Partially degradable friction-welded pure iron-stainless steel 316L bone pin.

    PubMed

    Nasution, A K; Murni, N S; Sing, N B; Idris, M H; Hermawan, H

    2015-01-01

    This article describes the development of a partially degradable metal bone pin, proposed to minimize the occurrence of bone refracture by avoiding the creation of holes in the bone after pin removal procedure. The pin was made by friction welding and composed of two parts: the degradable part that remains in the bone and the nondegradable part that will be removed as usual. Rods of stainless steel 316L (nondegradable) and pure iron (degradable) were friction welded at the optimum parameters: forging pressure = 33.2 kPa, friction time = 25 s, burn-off length = 15 mm, and heat input = 4.58 J/s. The optimum tensile strength and elongation was registered at 666 MPa and 13%, respectively. A spiral defect formation was identified as the cause for the ductile fracture of the weld joint. A 40-µm wide intermetallic zone was identified along the fusion line having a distinct composition of Cr, Ni, and Mo. The corrosion rate of the pin gradually decreased from the undeformed zone of pure iron to the undeformed zone of stainless steel 316L. All metallurgical zones of the pin showed no toxic effect toward normal human osteoblast cells, confirming the ppb level of released Cr and Ni detected in the cell media were tolerable.

  11. Comparing the Formability of AISI 304 and AISI 202 Stainless Steels

    NASA Astrophysics Data System (ADS)

    du Toit, M.; Steyn, H. G.

    2012-07-01

    The formability of AISI 202 austenitic stainless steel was compared with that of type AISI 304 stainless steel. Type 202 is a low-nickel austenitic stainless steel alloyed with manganese and nitrogen. In this study, the formability of the two grades was examined using Erichsen cupping tests and room temperature uniaxial tensile tests performed at various angles to the rolling direction. AISI 202 appears to work-harden at a slightly higher rate than AISI 304, even though the austenite in type 202 is more stable than that in 304 with respect to the formation of deformation-induced α' martensite. Although both grades are predicted to be susceptible to earing during deep drawing, AISI 202 displays a higher work-hardening exponent, higher average normal anisotropy, and a higher limiting drawing ratio than AISI 304. Similar cup heights were measured during Erichsen cupping tests, confirming that the two grades have very similar deep drawing properties. The results of this investigation therefore suggest that AISI 202 is a suitable alternative for AISI 304 in applications requiring good deep drawing properties.

  12. An EBSD investigation on flow localization and microstructure evolution of 316L stainless steel for Gen IV reactor applications

    NASA Astrophysics Data System (ADS)

    Wu, Xianglin; Pan, Xiao; Mabon, James C.; Li, Meimei; Stubbins, James F.

    2007-09-01

    Type 316L stainless steel has been selected as a candidate structural material in a series of current accelerator driven systems and Generation IV reactor conceptual designs. The material is sensitive to irradiation damage in the temperature range of 150-400 °C: even low levels of irradiation exposure, as small as 0.1 dpa, can cause severe loss of ductility during tensile loading. This process, where the plastic flow becomes highly localized resulting in extremely low overall ductility, is referred as flow localization. The process controlling this confined flow is related to the difference between the yield and ultimate tensile strengths such that large irradiation-induced increases in the yield strength result in very limited plastic flow leading to necking after very small levels of uniform elongation. In this study, the microstructural evolution controlling flow localization is examined. It is found that twinning is an important deformation mechanism at lower temperatures since it promotes the strain hardening process. At higher temperatures, twinning becomes energetically impossible since the activation of twinning is determined by the critical twinning stress, which increases rapidly with temperature. Mechanical twinning and dislocation-based planar slip are competing mechanisms for plastic deformation.

  13. Stress corrosion cracking and corrosion fatigue on 316L stainless steel in boric acid concentrated media at 320 C

    SciTech Connect

    Herms, E.; Olive, J.M.; Puiggali, M.; Boursier, J.M.

    1999-07-01

    Stress Corrosion Cracking (SCC) and Corrosion-Fatigue (CF) tests were performed in autoclave at 320 C in concentrated boric acid chlorinated media in presence of oxygen or hydrogen on type 316L austenitic stainless steel. Crack Growth Rates (CGR) are higher in non deaerated solutions for both SCC and CF than in hydrogenated solutions. CGR are relatively similar in CF and in SCC, excepted for high load ratio in CF where CGR are higher than in SCC. Detailed analysis of the fracture surface shows some distinct features between SCC and CF. Intergranular and transgranular mode of fracture are observed on SCC and CF. Fracture modes depend on the chemistry of solution in SCC and on frequency in CF. Traces of slip bands and crack front marking associated with oxide scale present on fracture surfaces exist in SCC and CF. Fatigue striations appear for low load ratio and high frequency. Secondary intergranular and transgranular cracking is observed only on SCC fracture surfaces and ligament morphology can be different in SCC relative to FC.

  14. Effect of Austenitic and Austeno-Ferritic Electrodes on 2205 Duplex and 316L Austenitic Stainless Steel Dissimilar Welds

    NASA Astrophysics Data System (ADS)

    Verma, Jagesvar; Taiwade, Ravindra V.

    2016-09-01

    This study addresses the effect of different types of austenitic and austeno-ferritic electrodes (E309L, E309LMo and E2209) on the relationship between weldability, microstructure, mechanical properties and corrosion resistance of shielded metal arc welded duplex/austenitic (2205/316L) stainless steel dissimilar joints using the combined techniques of optical, scanning electron microscope, energy-dispersive spectrometer and electrochemical. The results indicated that the change in electrode composition led to microstructural variations in the welds with the development of different complex phases such as vermicular ferrite, lathy ferrite, widmanstatten and intragranular austenite. Mechanical properties of welded joints were diverged based on compositions and solidification modes; it was observed that ferritic mode solidified weld dominated property wise. However, the pitting corrosion resistance of all welds showed different behavior in chloride solution; moreover, weld with E2209 was superior, whereas E309L exhibited lower resistance. Higher degree of sensitization was observed in E2209 weld, while lesser in E309L weld. Optimum ferrite content was achieved in all welds.

  15. Effect of surface passivation on corrosion resistance and antibacterial properties of Cu-bearing 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Zhao, Jinlong; Xu, Dake; Shahzad, M. Babar; Kang, Qiang; Sun, Ying; Sun, Ziqing; Zhang, Shuyuan; Ren, Ling; Yang, Chunguang; Yang, Ke

    2016-11-01

    The resistance for pitting corrosion, passive film stability and antibacterial performance of 316L-Cu SS passivated by nitric acid solution containing certain concentration of copper sulfate, were studied by electrochemical cyclic polarization, electrochemical impedance spectroscopy (EIS) and co-culture with bacteria. Inductively coupled plasma mass spectrometry (ICP-MS) was used to analyze the Cu2+ ions release from 316L-Cu SS surface. XPS analysis proved that the enrichment of CuO, Cr2O3 and Cr(OH)3 on the surface of specimen could simultaneously guarantee a better corrosion resistance and stable antibacterial properties. The biocompatibility evaluation determined by RTCA assay also indicated that the 316L-Cu SS after antibacterial passivation was completely biocompatible.

  16. Effects of passive films on corrosion resistance of uncoated SS316L bipolar plates for proton exchange membrane fuel cell application

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Ning, Xiaohui; Tang, Hongsheng; Guo, Liejin; Liu, Hongtan

    2014-11-01

    The effects of passive films on the corrosion behaviors of uncoated SS316L in anode and cathode environments of proton exchange membrane fuel cells (PEMFCs) are studied. Potentiodynamic and potentiostatic polarizations are employed to study the corrosion behavior; Mott-Schottky measurements are used to characterize the semiconductor properties of passive films; X-ray photoelectron spectroscopy (XPS) analyses are used to identify the compositions and the depth profiles of passive films. The passive films formed in the PEMFC anode and cathode environments under corresponding conditions both behave as n-type semiconductor. The passive film formed in the anode environment has a single-layer structure, Cr is the major element (Cr/Fe atomic ratio > 1), and the Cr/Fe atomic ratio decreases from the surface to the bulk; while the passive film formed in the PEMFC cathode environment has a bi-layer structure, Fe is the major element (Cr/Fe atomic ratio < 0.5), and in the external layer of the bi-layer structure Fe content increases rapidly and gradually in the internal layer. SS316L shows better corrosion resistance owing to both the high content of Cr oxide in the passive film and low band bending in normal PEMFC anode environments.

  17. Rapid heating tensile tests of hydrogen-charged high-energy-rate-forged 316L stainless steel

    SciTech Connect

    Mosley, W.C.

    1989-05-19

    316L stainless steel is a candidate material for construction of equipment that will be exposed to tritium. Proper design of the equipment will require an understanding of how tritium and its decay product helium affect mechanical properties. This memorandum describes results of rapid heating tensile testing of hydrogen-charged specimens of high-energy-rate-forged (HERF) 316L stainless steel. These results provide a data base for comparison with uncharged and tritium-charged-and-aged specimens to distinguish the effects of hydrogen and helium. Details of the experimental equipment and procedures and results for uncharged specimens were reported previously. 3 refs., 10 figs.

  18. Improved corrosion resistance of 316L stainless steel by nanocrystalline and electrochemical nitridation in artificial saliva solution

    NASA Astrophysics Data System (ADS)

    Lv, Jinlong; Liang, Tongxiang

    2015-12-01

    The fluoride ion in artificial saliva significantly changed semiconductor characteristic of the passive film formed on the surface of 316L stainless steels. The electrochemical results showed that nanocrystalline α‧-martensite improved corrosion resistance of the stainless steel in a typical artificial saliva compared with coarse grained stainless steel. Moreover, comparing with nitrided coarse grained stainless steel, corrosion resistance of the nitrided nanocrystalline stainless steel was also improved significantly, even in artificial saliva solution containing fluoride ion. The present study showed that the cryogenic cold rolling and electrochemical nitridation improved corrosion resistance of 316L stainless steel for the dental application.

  19. Fatigue life assessment of 316L stainless steel and DIN-1.4914 martensitic steel before and after TEXTOR exposure

    NASA Astrophysics Data System (ADS)

    Shakib, J. I.; Ullmaier, H.; Little, E. A.; Schmitz, W.; Faulkner, R. G.; Chung, T. E.

    1992-09-01

    The effects of plasma exposure in the TEXTOR tokomak on elevated temperature fatigue lifetime and failure micromechanisms of 316L austenitic stainless steel and DIN 1.4914 martensitic steel (NET reference heats) have been evaluated. Fatigue tests were carried out in vacuum in the temperature range 150°-450°C and compared with data from reference specimens.Plasma-induced surface modifications lead to significant deterioration in fatigue life of 316L steel, whereas the lifetime of 1.4914 steel is unaffected. Fatigue in the 1.4914 steel is surface-initiated only at high stresses. At low stress amplitudes internal fatigue initiation at inclusions was observed.

  20. Dissolution of a 316L stainless steel vessel by a pool of molten aluminum

    SciTech Connect

    Tutu, N.K.; Finfrock, C.C.; Lara, J.D.; Schwarz, C.E.; Greene, G.A.

    1993-01-01

    Two experiments to study the dissolution of a torospherical stainless steel vessel by an isothermal pool of molten aluminum have been performed. The test vessels consisted of 24 inch diameter 316L stainless steel ``ASME Flanged and Dished Heads.`` The nominal values of the average melt temperatures for the two tests were: 977{degree}C and 1007{degree}C. The measurements of the dissolution depth as a function of the position along the vessel surface showed the dissolution to be spatially highly non-uniform. Large variations in the dissolution depth with respect to the azimuthal coordinate were also observed. The maximum value of the measured time averaged dissolution rate was found to be 5.05 mm/hr, and this occurred near the edge of the molten pool. The concentration measurements indicated that the molten pool was highly stratified with respect to the concentration of stainless steel in the melt (molten aluminum-stainless steel solution).

  1. Cytocompatibility and mechanical properties of novel porous 316 L stainless steel.

    PubMed

    Kato, Komei; Yamamoto, Akiko; Ochiai, Shojiro; Wada, Masahiro; Daigo, Yuzo; Kita, Koichi; Omori, Kenichi

    2013-07-01

    Novel 316 L stainless steel (SS) foam with 85% porosity and an open pore diameter of 70-440 μm was developed for hard tissue application. The foam sheet with a 200-μm diameter had superior cell proliferation and penetration as identified through in vitro experiments. Calcification of human osteosarcoma cells in the SS foam was observed. Multi-layered foam preparation is a potential alternative technique that satisfies multi-functional requirements such as cell penetration and binding strength to the solid metal. In tensile tests, Young's modulus and the strength of the SS foam were 4.0 GPa and 11.2 MPa respectively, which is comparable with human cancellous bone. PMID:23623090

  2. Anticoagulant surface of 316 L stainless steel modified by surface-initiated atom transfer radical polymerization.

    PubMed

    Guo, Weihua; Zhu, Jian; Cheng, Zhenping; Zhang, Zhengbiao; Zhu, Xiulin

    2011-05-01

    Polished 316 L stainless steel (SS) was first treated with air plasma to enhance surface hydrophilicity and was subsequently allowed to react with 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane to introduce an atom transfer radical polymerization (ATRP) initiator. Accordingly, the surface-initiated atom transfer radical polymerization of polyethylene glycol methacrylate (PEGMA) was carried out on the surface of the modified SS. The grafting progress was monitored by water contact angle measurements, X-ray photoelectron spectroscopy and atomic force microscopy. The polymer thickness as a function different polymerization times was characterized using a step profiler. The anticoagulative properties of the PEGMA modified SS surface were investigated. The results showed enhanced anticoagulative to acid-citrate-dextrose (ACD) blood after grafting PEGMA on the SS surface. PMID:21528878

  3. A Shear Strain Route Dependency of Martensite Formation in 316L Stainless Steel.

    PubMed

    Kang, Suk Hoon; Kim, Tae Kyu; Jang, Jinsung; Oh, Kyu Hwan

    2015-06-01

    In this study, the effect of simple shearing on microstructure evolution and mechanical properties of 316L austenitic stainless steel were investigated. Two different shear strain routes were obtained by twisting cylindrical specimens in the forward and backward directions. The strain-induced martensite phase was effectively obtained by alteration of the routes. Formation of the martensite phase clearly resulted in significant hardening of the steel. Grain-size reduction and strain-induced martensitic transformation within the deformed structures of the strained specimens were characterized by scanning electron microscopy - electron back-scattered diffraction, X-ray diffraction, and the TEM-ASTAR (transmission electron microscopy - analytical scanning transmission atomic resolution, automatic crystal orientation/phase mapping for TEM) system. Significant numbers of twin networks were formed by alteration of the shear strain routes, and the martensite phases were nucleated at the twin interfaces.

  4. Controlling the electrodeposition, morphology and structure of hydroxyapatite coating on 316L stainless steel.

    PubMed

    Thanh, Dinh Thi Mai; Nam, Pham Thi; Phuong, Nguyen Thu; Que, Le Xuan; Anh, Nguyen Van; Hoang, Thai; Lam, Tran Dai

    2013-05-01

    Hydroxyapatite (HAp) coatings were prepared on 316L stainless steel (316LSS) substrates by electrochemical deposition in the solutions containing Ca(NO3)2·4H2O and NH4H2PO4 at different electrolyte concentrations. Along with the effect of precursor concentration, the influence of temperature and H2O2 content on the morphology, structure and composition of the coating was thoroughly discussed with the help of X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectra. The in vitro tests in simulated body fluids (SBF) were carried out and then the morphological and structural changes were estimated by SEM and electrochemical techniques (open circuit potential, polarization curves, Nyquist and Bode spectra measurements). Being simple and cost-effective, this method is advantageous for producing HAp implant materials with good properties/characteristics, aiming towards in vivo biomedical applications.

  5. Relative Defect Density Measurements of Laser Shock Peened 316L Stainless Steel Using Positron Annihilation Spectroscopy

    SciTech Connect

    Marcus A. Gagliardi; Bulent H. Sencer; A. W. Hunt; Stuart A. Maloy; George T. Gray III

    2011-12-01

    The surface of an annealed 316L stainless steel coupon was laser shock peened and Vickers hardness measurements were subsequently taken of its surface. This Vickers hardness data was compared with measurements taken using the technique of positron annihilation Doppler broadening spectroscopy. When compared, a correlation was found between the Vickers hardness data measurements and those made using Doppler broadening spectroscopy. Although materials with a high defect density can cause the S-parameter measurements to saturate, variations in the Sparameter measurements suggest that through further research the Doppler broadening technique could be used as a viable alternative to measuring a material's hardness. In turn, this technique, could be useful in industrial settings where surface hardness and surface defects are used to predict lifetime of components.

  6. Effect of Laser Peening without Coating on 316L austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Sathyajith, S.; kalainathan, S.

    2015-02-01

    Laser Peening without Coating (LPwC) is an innovative surface modification technique used for the in-suit preventive maintenance of nuclear reactor components using frequency doubled (green) laser. The advantage of LPwC is that the laser required for this technique is in milli joule range and the processes can perform in aqueous environment. This paper discussed the effect of LPwC on 316L austenitic stainless steel using low energy Nd: YAG laser with various laser pulse density. The base specimen and laser peened specimen were subjected to surface residual stress, surface morphology, micro hardness and potentiodynamic polarization studies. The laser peened surface exhibit significant improvement in surface compressive residual stress. The depth profile of micro hardness revealed higher strain hardening on laser peened specimens. Though corrosion potential reported an anodic shift,current density is found to be increased after LPwC for the specimen peened with higher pulse density.

  7. Effects of dissolved oxygen on electrochemical and semiconductor properties of 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Feng, Zhicao; Cheng, Xuequn; Dong, Chaofang; Xu, Lin; Li, Xiaogang

    2010-12-01

    The effects of dissolved oxygen on the electrochemical behavior and semiconductor properties of passive film formed on 316L SS in three solutions with different dissolved oxygen were studied by using polarization curve, Mott-Schottky analysis and the point defect model (PDM). The results show that higher dissolved oxygen accelerates both anodic and cathodic process. Based on Mott-Schottky analysis and PDM, the key parameters for passive film, donor density Nd, flat-band potential Efb and diffusivity of defects D0 were calculated. The results display that Nd(1-7 × 10 27 m -3) and D0(1-18 × 10 -16 cm 2/s) increase and Efb value reduces with the dissolved oxygen in solution.

  8. Corrosion resistance improvement for 316L stainless steel coronary artery stents by trimethylsilane plasma nanocoatings

    PubMed Central

    Jones, John Eric; Chen, Meng; Yu, Qingsong

    2015-01-01

    To improve their corrosion resistance and thus long-term biocompatibility, 316L stainless steel coronary artery stents were coated with trimethylsilane (TMS) plasma coatings of 20–25 nm in thickness. Both direct current (DC) and radio-frequency (RF) glow discharges were utilized for TMS plasma coatings and additional NH3/O2 plasma treatment to tailor the surface properties. X-ray photoelectron spectroscopy (XPS) was used to characterize the coating surface chemistry. It was found that both DC and RF TMS plasma coatings had Si- and C-rich composition, and the O-and N-contents on the surfaces were substantially increased after NH3/O2 plasma treatment. Surface contact angle measurements showed that DC TMS plasma nanocoating with NH3/O2 plasma treatment generated very hydrophilic surface. The corrosion resistance of TMS plasma coated stents was evaluated through potentiodynamic polarization and electro-chemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization demonstrated that the TMS plasma coated stents imparted higher corrosion potential and pitting potential, as well as lower corrosion current densities as compared with uncoated controls. The surface morphology of stents before and after potentiodynamic polarization testing was analyzed with scanning electron microscopy, which indicated less corrosion on coated stents than uncoated controls. It was also noted that, from EIS data, the hydrophobic TMS plasma nanocoatings showed stable impedance modulus at 0.1 Hz after 21 day immersion in an electrolyte solution. These results suggest improved corrosion resistance of the 316L stainless steel stents by TMS plasma nanocoatings and great promise in reducing and blocking metallic ions releasing into the bloodstream. PMID:24500866

  9. Corrosion resistance improvement for 316L stainless steel coronary artery stents by trimethylsilane plasma nanocoatings.

    PubMed

    Eric Jones, John; Chen, Meng; Yu, Qingsong

    2014-10-01

    To improve their corrosion resistance and thus long-term biocompatibility, 316L stainless steel coronary artery stents were coated with trimethylsilane (TMS) plasma coatings of 20-25 nm in thickness. Both direct current (DC) and radio-frequency (RF) glow discharges were utilized for TMS plasma coatings and additional NH₃/O₂ plasma treatment to tailor the surface properties. X-ray photoelectron spectroscopy (XPS) was used to characterize the coating surface chemistry. It was found that both DC and RF TMS plasma coatings had Si- and C-rich composition, and the O- and N-contents on the surfaces were substantially increased after NH₃/O₂ plasma treatment. Surface contact angle measurements showed that DC TMS plasma nanocoating with NH₃/O₂ plasma treatment generated very hydrophilic surface. The corrosion resistance of TMS plasma coated stents was evaluated through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization demonstrated that the TMS plasma coated stents imparted higher corrosion potential and pitting potential, as well as lower corrosion current densities as compared with uncoated controls. The surface morphology of stents before and after potentiodynamic polarization testing was analyzed with scanning electron microscopy, which indicated less corrosion on coated stents than uncoated controls. It was also noted that, from EIS data, the hydrophobic TMS plasma nanocoatings showed stable impedance modulus at 0.1 Hz after 21 day immersion in an electrolyte solution. These results suggest improved corrosion resistance of the 316L stainless steel stents by TMS plasma nanocoatings and great promise in reducing and blocking metallic ions releasing into the bloodstream.

  10. Electrochemical and in vitro bioactivity of polypyrrole/ceramic nanocomposite coatings on 316L SS bio-implants.

    PubMed

    Madhan Kumar, A; Nagarajan, S; Ramakrishna, Suresh; Sudhagar, P; Kang, Yong Soo; Kim, Hyongbum; Gasem, Zuhair M; Rajendran, N

    2014-10-01

    The present investigation describes the versatile fabrication and characterization of a novel composite coating that consists of polypyrrole (PPy) and Nb2O5 nanoparticles. Integration of the two materials is achieved by electrochemical deposition on 316L stainless steel (SS) from an aqueous solution of oxalic acid containing pyrrole and Nb2O5 nanoparticles. Fourier transform infrared spectral (FTIR) and X-ray diffraction (XRD) studies revealed that the existence of Nb2O5 nanoparticles in PPy matrix with hexagonal structure. Surface morphological analysis showed that the presence of Nb2O5 nanoparticles strongly influenced the surface nature of the nanocomposite coated 316L SS. Micro hardness results revealed the enhanced mechanical properties of PPy nanocomposite coated 316L SS due to the addition of Nb2O5 nanoparticles. The electrochemical studies were carried out using cyclic polarization and electrochemical impedance spectroscopy (EIS) measurements. In order to evaluate the biocompatibility, contact angle measurements and in vitro characterization were performed in simulated body fluid (SBF) and on MG63 osteoblast cells. The results showed that the nanocomposite coatings exhibit superior biocompatibility and enhanced corrosion protection performance over 316L SS than pure PPy coatings.

  11. Effect of thermal exposure in helium on mechanical properties and microstructure of 316L and P91

    NASA Astrophysics Data System (ADS)

    Kunzova, Klara; Berka, Jan; Siegl, Jan; Hausild, Petr

    2016-04-01

    In this paper, the effects of high temperature exposure in air as well as in impure He on mechanical properties of 316L and P91 steels were investigated. The experimental programme was part of material design of new experimental facility - high temperature helium loop. Some of the specimens were exposed in air at 750 °C for up to 1000 h. Another set of specimens were exposed in impure helium containing 1 ppmv CO2, 2 ppmv O2, 35 ppmv CH4, 250 ppmv CO and 400 ppmv H2 at 750 °C for up to 1000 h. Metalographical analysis, tensile tests, fracture toughness and hardness tests of exposed and non-exposed specimens were carried out. After the exposure both in air and He, the ultimate tensile strength of P91 decreased significantly more than that of 316L. After the exposure in He, the fracture toughness of 316L was reduced to 60% while fracture toughness of P91 showed no significant changes. The hardness of P91 decreased with exposure time in air. The measurement of the hardness of 316L was very scattered the most probably due to the heterogeneities in microstructure, the trend was not possible to evaluate.

  12. A novel silica nanotube reinforced ionic incorporated hydroxyapatite composite coating on polypyrrole coated 316L SS for implant application.

    PubMed

    Prem Ananth, K; Joseph Nathanael, A; Jose, Sujin P; Oh, Tae Hwan; Mangalaraj, D

    2016-02-01

    An attempt has been made to deposit a novel smart ion (Sr, Zn, Mg) substituted hydroxyapatite (I-HAp) and silica nanotube (SiNTs) composite coatings on polypyrrole (PPy) coated surgical grade 316L stainless steel (316L SS) to improve its biocompatibility and corrosion resistance. The I-HAp/SiNTS/PPy bilayer coating on 316L SS was prepared by electrophoretic deposition technique. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies were carried out. These results confirmed the significant improvement of the corrosion resistance of the 316L SS alloy by the I-HAp/SiNTs/PPy bilayer composite coating. The adhesion strength and hardness test confirmed the anticipated mechanical properties of the composite. A low contact angle value revealed the hydrophilic nature. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used for the leach out analysis of the samples. Added to this, the bioactivity of the composite was analyzed by observing the apatite formation in the SBF solution for 7, 14, 21 and 28days of incubation. An enhancement of in vitro osteoblast attachment and cell viability was observed, which could lead to the optimistic orthopedic and dental applications.

  13. Effects of Heat Treatments on Microstructure Changes in The Interface of Cu/SS316L Joint Materials

    SciTech Connect

    Xu, Q.; Yoshiie, T.; Edwards, Danny J.

    2000-09-01

    In both joints iron and chromium diffused from the stainless steel into the copper alloy, producing a narrow zone of about a 15 ?m containing FeCr precipitates and small voids. Failure in some bending tests occurred by a crack propagating through this zone in a direction parallel to the interface, indicating that the formation of these precipitates may not be conducive to good joint properties. The results of annealing experiments showed that temperatures # 673 K did not change the initial microstructure or composition of CuAl25/SS316L and CuNiBe/SS316L joints. Although there are no data from annealing experiments longer than 100 hours, it is expected that the microstructure and composition of CuAl25/SS316L and CuNiBe/SS316L are stable under the thermal operating conditions of fusion reactors. However, irradiation may lead to significant changes because of radiation-enhanced segregation, precipitation or dissolution near and at the interface that could alter the properties. In addition, the preexisting voids near the interface of the joints may coarsen under irradiation and enhance the sensitivity of joints to failure. Given the uncertainties in the response to irradiation, neutron irradiation experiments should be performed at appropriate temperatures to investigate the response of the different materials.

  14. Reduced graphene oxide growth on 316L stainless steel for medical applications

    NASA Astrophysics Data System (ADS)

    Cardenas, L.; MacLeod, J.; Lipton-Duffin, J.; Seifu, D. G.; Popescu, F.; Siaj, M.; Mantovani, D.; Rosei, F.

    2014-07-01

    We report a new method for the growth of reduced graphene oxide (rGO) on the 316L alloy of stainless steel (SS) and its relevance for biomedical applications. We demonstrate that electrochemical etching increases the concentration of metallic species on the surface and enables the growth of rGO. This result is supported through a combination of Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), density functional theory (DFT) calculations and static water contact angle measurements. Raman spectroscopy identifies the G and D bands for oxidized species of graphene at 1595 cm-1 and 1350 cm-1, respectively, and gives an ID/IG ratio of 1.2, indicating a moderate degree of oxidation. XPS shows -OH and -COOH groups in the rGO stoichiometry and static contact angle measurements confirm the wettability of rGO. SEM and AFM measurements were performed on different substrates before and after coronene treatment to confirm rGO growth. Cell viability studies reveal that these rGO coatings do not have toxic effects on mammalian cells, making this material suitable for biomedical and biotechnological applications.

  15. Reduced graphene oxide growth on 316L stainless steel for medical applications.

    PubMed

    Cardenas, L; MacLeod, J; Lipton-Duffin, J; Seifu, D G; Popescu, F; Siaj, M; Mantovani, D; Rosei, F

    2014-08-01

    We report a new method for the growth of reduced graphene oxide (rGO) on the 316L alloy of stainless steel (SS) and its relevance for biomedical applications. We demonstrate that electrochemical etching increases the concentration of metallic species on the surface and enables the growth of rGO. This result is supported through a combination of Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), density functional theory (DFT) calculations and static water contact angle measurements. Raman spectroscopy identifies the G and D bands for oxidized species of graphene at 1595 cm(-1) and 1350 cm(-1), respectively, and gives an ID/IG ratio of 1.2, indicating a moderate degree of oxidation. XPS shows -OH and -COOH groups in the rGO stoichiometry and static contact angle measurements confirm the wettability of rGO. SEM and AFM measurements were performed on different substrates before and after coronene treatment to confirm rGO growth. Cell viability studies reveal that these rGO coatings do not have toxic effects on mammalian cells, making this material suitable for biomedical and biotechnological applications.

  16. Electrophoretic deposition of bioactive glass coating on 316L stainless steel and electrochemical behavior study

    NASA Astrophysics Data System (ADS)

    Mehdipour, Mehrad; Afshar, Abdollah; Mohebali, Milad

    2012-10-01

    In this research, submicron bioactive glass (BG) particles were synthesized by a sol-gel process and were then coated on a 316L stainless steel substrate using an electrophoretic deposition (EPD) technique. Stable suspension of bioactive glass powders in ethanol solvent was prepared by addition of triethanol amine (TEA), which increased zeta potential from 16.5 ± 1.6 to 20.3 ± 1.4 (mv). Thickness, structure and electrochemical behavior of the coating were characterized. SEM studies showed that increasing EPD voltage leads to a coating with more agglomerated particles, augmented porosity and micro cracks. The results of Fourier transformed infrared (FTIR) spectroscopy revealed the adsorption of TEA via methyl and amid groups on bioactive glass particles. Presence of bioactive glass coating reduced corrosion current density (icorr) and shifted corrosion potential (Ecorr) toward more noble values in artificial saliva at room temperature. Percent porosity of the coating measured by potentiodynamic polarization technique increased as EPD voltage was raised. The results of impedance spectroscopic studies demonstrated that the coating acts as a barrier layer in artificial saliva.

  17. Corrosion Resistance of Ti-O Film Modified 316L Stainless Steel Coronary Stents In Vitro

    NASA Astrophysics Data System (ADS)

    Liu, Hengquan; Leng, Yongxiang; Huang, Nan

    2012-03-01

    This article dealt with improving corrosion resistance of stent modified using Ti-O film. Ti-O films of various thicknesses were grown on the surface of 316L stainless steel (SS) stents by metal vacuum arc source deposition technology, and the phase composition, the thickness and the adhesion between films and substance were investigated by micro-x-ray diffraction (Micro-XRD), surface profilometer, and scanning electron microscopy (SEM) separately. The corrosion resistance of modified stent was assessed by polarization test in phosphate buffered solution (37 ± 1 °C). The result shows that the Ti-O films were very smooth and uniform. There were not any cracks and delaminations after dilation by angioplasty, the adhesion between Ti-O film and stent is satisfactory. The open circuit potential (OCP) of the Ti-O film modified stents was higher than that of the bare stents; it shows that the electrochemical stability of modified stents was more than bare stents. The polarization test result indicates that the passivation stability and anti-breakdown performance of Ti-O film stents had better than bare stents, and no pitting was observed on the surface of both modified stents, but the local film striations were found on the stent surface of the thicker film, which indicated that the Ti-O film stents with certain thickness has good corrosion resistance.

  18. Computaional Modeling of the Stability of Crevice Corrosion of Wetted SS316L

    SciTech Connect

    F. Cui; F.J. Presuel-Moreno; R.G. Kelly

    2006-04-17

    The stability of localized corrosion sites on SS 316L exposed to atmospheric conditions was studied computationally. The localized corrosion system was decoupled computationally by considering the wetted cathode and the crevice anode separately and linking them via a constant potential boundary condition at the mouth of the crevice. The potential of interest for stability was the repassivation potential. The limitations on the ability of the cathode that are inherent due to the restricted geometry were assessed in terms of the dependence on physical and electrochemical parameters. Physical parameters studied include temperature, electrolyte layer thickness, solution conductivity, and the size of the cathode, as well as the crevice gap for the anode. The current demand of the crevice was determined considering a constant crevice solution composition that simulates the critical crevice solution as described in the literature. An analysis of variance showed that the solution conductivity and the length of the cathode were the most important parameters in determining the total cathodic current capacity of the external surface. A semi-analytical equation was derived for the total current from a restricted geometry held at a constant potential at one end. The equation was able to reproduce all the model computation results both for the wetted external cathode and the crevice and give good explanation on the effects of physicochemical and kinetic parameters.

  19. Microbiological test results using three urine pretreatment regimes with 316L stainless steel

    NASA Technical Reports Server (NTRS)

    Huff, Timothy L.

    1993-01-01

    Three urine pretreatments, (1) Oxone (Dupont) and sulfuric acid, (2) sodium hypochlorite and sulfuric acid, (3) and ozone, were studied for their ability to reduce microbial levels in urine and minimize surface attachment to 316L stainless steel coupons. Urine samples inoculated with Bacillus insolitus and a filamentous mold, organisms previously recovered from the vapor compression distillation subsystem of NASA Space Station Freedom water recovery test were tested in glass corrosion cells containing base or weld metal coupons. Microbial levels, changes in pH, color, turbidity, and odor of the fluid were monitored over the course of the 21-day test. Specimen surfaces were examined by scanning electron microscopy at completion of the test for microbial attachment. Ozonated urine samples were less turbid and had lower microbial levels than controls or samples receiving other pretreatments. Base metal coupons receiving pretreatment were relatively free of attached bacteria. However, well-developed biofilms were found in the heat-affected regions of welded coupons receiving Oxone and hypochlorite pretreatments. Few bacteria were observed in the same regions of the ozone pretreatment sample.

  20. Welding of 316L Austenitic Stainless Steel with Activated Tungsten Inert Gas Process

    NASA Astrophysics Data System (ADS)

    Ahmadi, E.; Ebrahimi, A. R.

    2015-02-01

    The use of activating flux in TIG welding process is one of the most notable techniques which are developed recently. This technique, known as A-TIG welding, increases the penetration depth and improves the productivity of the TIG welding. In the present study, four oxide fluxes (SiO2, TiO2, Cr2O3, and CaO) were used to investigate the effect of activating flux on the depth/width ratio and mechanical property of 316L austenitic stainless steel. The effect of coating density of activating flux on the weld pool shape and oxygen content in the weld after the welding process was studied systematically. Experimental results indicated that the maximum depth/width ratio of stainless steel activated TIG weld was obtained when the coating density was 2.6, 1.3, 2, and 7.8 mg/cm2 for SiO2, TiO2, Cr2O3, and CaO, respectively. The certain range of oxygen content dissolved in the weld, led to a significant increase in the penetration capability of TIG welds. TIG welding with active fluxes can increase the delta-ferrite content and improves the mechanical strength of the welded joint.

  1. Galvanic deposition and characterization of brushite/hydroxyapatite coatings on 316L stainless steel.

    PubMed

    Blanda, Giuseppe; Brucato, Valerio; Pavia, Francesco Carfì; Greco, Silvia; Piazza, Salvatore; Sunseri, Carmelo; Inguanta, Rosalinda

    2016-07-01

    In this work, brushite and brushite/hydroxyapatite (BS, CaHPO4·H2O; HA, Ca10(PO4)6(OH)2) coatings were deposited on 316L stainless steel (316LSS) from a solution containing Ca(NO3)2·4H2O and NH4H2PO4 by a displacement reaction based on a galvanic contact, where zinc acts as sacrificial anode. Driving force for the cementation reaction arises from the difference in the electrochemical standard potentials of two different metallic materials (316LSS and Zn) immersed in an electrolyte, so forming a galvanic contact leading to the deposition of BS/HA on nobler metal. We found that temperature and deposition time affect coating features (morphology, structure, and composition). Deposits were characterized by means of several techniques. The morphology was investigated by scanning electron microscopy, the elemental composition was obtained by X-ray energy dispersive spectroscopy, whilst the structure was identified by Raman spectroscopy and X-ray diffraction. BS was deposited at all investigated temperatures covering the 316LSS surface. At low and moderate temperature, BS coatings were compact, uniform and with good crystalline degree. On BS layers, HA crystals were obtained at 50°C for all deposition times, while at 25°C, its presence was revealed only after long deposition time. Electrochemical studies show remarkable improvement in corrosion resistance. PMID:27127032

  2. Preliminary histological study of connective tissue response to Zinalco and stainless steel 316L implants after 120 days.

    PubMed

    Piña, C; Torres, C K; Guzmán, J

    1998-02-01

    Circular plates of Zinalco alloy (80 wt% Zn, 1.5 wt% Cu, 18.5 wt% Al) and stainless steel (SS) 316L were implanted in 12 female Wistar rats subcutaneously and intramuscularly to compare organism response, 120 days after implantation. The tissues surrounding the implants were analysed employing hematoxilin and eosin (H-E) and Gallego's trichromic techniques (GTT). Findings indicate that the reaction to Zinalco alloy was similar to the reaction to SS 316L. The Zn, Al and Cu concentrations in blood were measured, without evidence of any alteration due to implants. The presence and distribution of Zn, Al and Cu components of Zinalco alloy were detected in tissues by energy dispersive X-ray microanalysis.

  3. Result of International Round Robin Test on Young's Modulus Measurement of 304L and 316L Steels at Cryogenic Temperatures

    NASA Astrophysics Data System (ADS)

    Shibata, K.; Ogata, T.; Nyilas, A.; Walsh, R. P.; Millet, M. F.; Shindo, Y.; Fujii, H.; Ishio, K.; Nakajima, H.; Mitterbacher, H.; Toplosky, V. J.; Ohmiya, S.; Takano, K.; Gigante, P.

    2006-03-01

    Ogata et al. reported in 1996 results of international Round Robin tests on mechanical property measurement of several metals at cryogenic temperatures. Following the report, the standard deviation of Young's modulus of 316L steel is much larger than those of yield and tensile strengths, that is, 4.6 % of the mean value for Young's modulus, while 1.4 % and 1.6 % of the mean values for yield and for tensile strengths, respectively. Therefore, an international Round Robin test on Young's modulus of two austenitic stainless steels at cryogenic temperatures under the participation often institutes from four nations has been initiated within these two years. As a result, the ratios of standard deviation to the mean values are 4.2 % for 304L and 3.6 % for 316L. Such a drop in the standard deviation is attributable to the decrease in the number of institute owing to the application of single extensometer or direct strain gage technique.

  4. Structural, electrical and magnetic measurements on oxide layers grown on 316L exposed to liquid lead-bismuth eutectic

    NASA Astrophysics Data System (ADS)

    Hosemann, Peter; Hofer, Christian; Hlawacek, Gregor; Li, Ning; Maloy, Stuart A.; Teichert, Christian

    2012-02-01

    Fast reactors and spallation neutron sources may use lead-bismuth eutectic (LBE) as a coolant. Its physical, chemical, and irradiation properties make it a safe coolant compared to Na cooled designs. However, LBE is a corrosive medium for most steels and container materials. The present study was performed to evaluate the corrosion behavior of the austenitic steel 316L (in two different delivery states). Detailed atomic force microscopy, magnetic force microscopy, conductive atomic force microscopy, and scanning transmission electron microscopy analyses have been performed on the oxide layers to get a better understanding of the corrosion and oxidation mechanisms of austenitic and ferritic/martensitic stainless steel exposed to LBE. The oxide scale formed on the annealed 316L material consisted of multiple layers with different compositions, structures, and properties. The innermost oxide layer maintained the grain structure of what used to be the bulk steel material and shows two phases, while the outermost oxide layer possessed a columnar grain structure.

  5. CORROSION STUDY FOR THE EFFLUENT TREATMENT FACILITY CHROME (VI) REDUCTANT SOLUTION USING 304 AND 316L STAINLESS STEEL

    SciTech Connect

    DUNCAN JB; WYRAS RB

    2007-10-08

    This report documents the laboratory testing and analyses as directed under the test plan, RPP PLAN-34065, and documented in laboratory notebooks HNF 2742 and HNF-N-473-1. The purpose of this study was to evaluate and compare the electrochemical corrosion and pitting susceptibility of the 304 and 316L stainless steel in the acidified reducing solution that will be contained in either the secondary waste receiving tank or concentrate tank.

  6. The effect of hydrogen peroxide on uranium oxide films on 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Wilbraham, Richard J.; Boxall, Colin; Goddard, David T.; Taylor, Robin J.; Woodbury, Simon E.

    2015-09-01

    For the first time the effect of hydrogen peroxide on the dissolution of electrodeposited uranium oxide films on 316L stainless steel planchets (acting as simulant uranium-contaminated metal surfaces) has been studied. Analysis of the H2O2-mediated film dissolution processes via open circuit potentiometry, alpha counting and SEM/EDX imaging has shown that in near-neutral solutions of pH 6.1 and at [H2O2] ⩽ 100 μmol dm-3 the electrodeposited uranium oxide layer is freely dissolving, the associated rate of film dissolution being significantly increased over leaching of similar films in pH 6.1 peroxide-free water. At H2O2 concentrations between 1 mmol dm-3 and 0.1 mol dm-3, formation of an insoluble studtite product layer occurs at the surface of the uranium oxide film. In analogy to corrosion processes on common metal substrates such as steel, the studtite layer effectively passivates the underlying uranium oxide layer against subsequent dissolution. Finally, at [H2O2] > 0.1 mol dm-3 the uranium oxide film, again in analogy to common corrosion processes, behaves as if in a transpassive state and begins to dissolve. This transition from passive to transpassive behaviour in the effect of peroxide concentration on UO2 films has not hitherto been observed or explored, either in terms of corrosion processes or otherwise. Through consideration of thermodynamic solubility product and complex formation constant data, we attribute the transition to the formation of soluble uranyl-peroxide complexes under mildly alkaline, high [H2O2] conditions - a conclusion that has implications for the design of both acid minimal, metal ion oxidant-free decontamination strategies with low secondary waste arisings, and single step processes for spent nuclear fuel dissolution such as the Carbonate-based Oxidative Leaching (COL) process.

  7. COMPUTATIONAL MODELING OF CATHODIC LIMITATIONS ON LOCALIZED CORROSION OF WETTED SS 316L, AT ROOM TEMPERATURE

    SciTech Connect

    F. Cui; F.J. Presuel-Moreno; R.G. Kelly

    2005-10-13

    The ability of a SS316L surface wetted with a thin electrolyte layer to serve as an effective cathode for an active localized corrosion site was studied computationally. The dependence of the total net cathodic current, I{sub net}, supplied at the repassivation potential E{sub rp} (of the anodic crevice) on relevant physical parameters including water layer thickness (WL), chloride concentration ([Cl{sup -}]) and length of cathode (Lc) were investigated using a three-level, full factorial design. The effects of kinetic parameters including the exchange current density (i{sub o,c}) and Tafel slope ({beta}{sub c}) of oxygen reduction, the anodic passive current density (i{sub p}) (on the cathodic surface), and E{sub rp} were studied as well using three-level full factorial designs of [Cl{sup -}] and Lc with a fixed WL of 25 {micro}m. The study found that all the three parameters WL, [Cl{sup -}] and Lc as well as the interactions of Lc x WL and Lc x [Cl{sup -}] had significant impact on I{sub net}. A five-factor regression equation was obtained which fits the computation results reasonably well, but demonstrated that interactions are more complicated than can be explained with a simple linear model. Significant effects on I{sub net} were found upon varying either i{sub o,c}, {beta}{sub c}, or E{sub rp}, whereas i{sub p} in the studied range was found to have little impact. It was observed that I{sub net} asymptotically approached maximum values (I{sub max}) when Lc increased to critical minimum values. I{sub max} can be used to determine the stability of coupled localized corrosion and the critical Lc provides important information for experimental design and corrosion protection.

  8. Laser Surface Treatment of Stellite 6 Coating Deposited by HVOF on 316L Alloy

    NASA Astrophysics Data System (ADS)

    Shoja-Razavi, Reza

    2016-07-01

    This research aimed to study the effects of laser glazing treatment on microstructure, hardness, and oxidation behavior of Stellite 6 coating deposited by high velocity oxygen fuel (HVOF) spraying. The as-sprayed Stellite 6 coating (ST-HVOF) was subjected to single-pass and multiple-pass laser treatments to achieve the optimum glazing parameters. Microstructural characterizations were performed by x-ray diffractometry and field emission scanning electron microscopy equipped with energy-dispersive spectroscopy. Two-step optimization showed that laser treatment at the power of 200 W with a scan rate of 4 mm/s causes a surface layer with a thickness of 208 ± 32 µm to be remelted, while the underlying layers retain the original ST-HVOF coating structure. The obtained sample (ST-Glazing) exhibited a highly dense and uniform structure with an extremely low porosity of ~0.3%, much lower than that of ST-HVOF coating (2.3%). The average microhardness of ST-Glazing was measured to be 519 Hv0.3 indicating a 17% decrease compared to ST-HVOF (625 Hv0.3) due to the residual stress relief and dendrite coarsening from submicron size to ~3.4 µm after laser treatment. The lowest oxidation mass gain was obtained for ST-Glazing by 2 mg/cm2 after 8 cycles at 900 °C indicating 52 and 84% improvement in oxidation resistance in comparison to ST-HVOF and bare 316L steel substrates, respectively.

  9. Repassivation behavior of 316L stainless steel in borate buffer solution: Kinetics analysis of anodic dissolution and film formation

    NASA Astrophysics Data System (ADS)

    Xu, Haisong; Sun, Dongbai; Yu, Hongying

    2015-12-01

    The repassivation behavior of metals or alloys after oxide film damage determines the development of local corrosion and corrosion resistance. In this work, the repassivation kinetics of 316L stainless steel (316L SS) are investigated in borate buffer solution (pH 9.1) by using the abrading electrode technique. The current densities flowing from bare 316L SS surface are measured by potentiostatic method and analyzed to characterize repassivation kinetics. The initial stages of current decay (t < 500 ms) are discussed according to a film growth model, which describes the initial current transient should be divided into substrate dissolution current and passive film formation current based on Avrami kinetics. Then the two independent components are analyzed individually. The film formation rate and the thickness of film are compared in different applied potential. It is shown that anodic dissolution dominates the repassivation for a short time during the early times, and a higher applied potential will promote the anodic dissolution of metal. The film growth rate increases slightly with increasing in potential. Correspondingly, increase in applied potential from 0 VSCE to 0.8 VSCE results in thicker monolayer, which covers the whole bare surface at the time of θ = 1. The electric field strengths through the thin passive film could reach 3.97 × 106 V cm-1.

  10. Nanohardness, corrosion and protein adsorption properties of CuAlO2 films deposited on 316L stainless steel for biomedical applications

    NASA Astrophysics Data System (ADS)

    Chang, Shih-Hang; Chen, Jian-Zhang; Hsiao, Sou-Hui; Lin, Guan-Wei

    2014-01-01

    This study preliminarily assesses the biomedical applications of CuAlO2 coatings according to nanoindentation, electrochemical, and protein adsorption tests. Nanoindentation results revealed that the surface hardness of 316L stainless steel increased markedly after coating with CuAlO2 films. Electrochemical tests of corrosion potential, breakdown potential, and corrosion current density showed that the corrosion resistance properties of 316L stainless steel are considerably improved by CuAlO2 coatings. Bicinchoninic acid (BCA) protein assay results revealed that the protein adsorption behavior of 316L stainless steel did not exhibit notable differences with or without CuAlO2 coatings. A CuAlO2 coating of 100 nm thickness improved the surface nanohardness and corrosion resistance ability of 316L stainless steel. CuAlO2 is a potential candidate for biomaterial coating applications, particularly for surface modification of fine, delicate implants.

  11. Effect of grain refinement and electrochemical nitridation on corrosion resistance of the 316L stainless steel for bipolar plates in PEMFCs environment

    NASA Astrophysics Data System (ADS)

    Jinlong, Lv; Tongxiang, Liang; Hongyun, Luo

    2015-10-01

    The stain-induced nanocrystalline α'-martensite was obtained by cryogenic cold rolling at liquid-nitrogen temperature for 316L stainless steel. The electrochemical results showed nanocrystalline 316L stainless steel deteriorated its corrosion resistance in a typical proton exchange membrane fuel cell environment compared with coarse grained one. However, comparing with electrochemically nitrided coarse grained stainless steel, electrochemically nitrided nanocrystalline stainless steel improved significantly corrosion resistance in the same environment, which was supported further by Mott-Shottky analysis. X-ray photoelectron spectroscopy analysis revealed that the nanocrystalline promoted the enrichment of nitrogen and chromium and inhibited form of NH3 on the surface, which could significantly improve the corrosion resistance of the 316L stainless steel. The present study showed that the electrochemically nitrided 316L stainless steel was more suitable for the bipolar plates in proton exchange membrane fuel cell environment than the untreated one, especially for nanocrystalline stainless steel.

  12. Study of the surface roughness evolution in fatigued 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Wang, Ye

    life. Scanning Whitelight Interferometric Microscope (SWLI) was applied to quantitatively study the surface roughness evolution of polycrystalline 316L stainless steel fatigue specimen. We demonstrated that the surface roughness increased with fatigue cycles during the entire fatigue process. In addition, we discovered that surface roughness increases at early fatigue stage were contributed by slip band formation while surface roughness increases at later-stage fatigue were due to the out-of-plane displacement of adjacent grains. Crack initiation and development has also been identified.

  13. A mechanism for the enhanced attachment and proliferation of fibroblasts on anodized 316L stainless steel with nano-pit arrays.

    PubMed

    Ni, Siyu; Sun, Linlin; Ercan, Batur; Liu, Luting; Ziemer, Katherine; Webster, Thomas J

    2014-08-01

    In this study, 316L stainless steel with tunable nanometer pit sizes (0, 25, 50, and 60 nm) were fabricated by an anodization procedure in an ethylene glycol electrolyte solution containing 5 vol % perchloric acid. The surface morphology and elemental composition of the 316L stainless steel were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The nano-pit arrays on all of the 316L stainless steel samples were in a regular arrangement. The surface properties of the 316L stainless steel nano-pit surface showed improved wettability properties as compared with the untreated 316L stainless steel, as demonstrated by the lower contact angles which dropped from 83.0° to 28.6 to 45.4°. The anodized 316L stainless steel surfaces with 50 nm and 60 nm diameter pits were also more rough at the nanoscale. According to MTT assays, compared with unanodized (that is, nano-smooth) surfaces, the 50 and 60 nm diameter nano-pit surfaces dramatically enhanced initial human dermal fibroblast attachment and growth for up to 3 days in culture. Mechanistically, this study also provided the first evidence of greater select protein adsorption (specifically, vitronectin and fibronectin which have been shown to enhance fibroblast adhesion) on the anodized 316L stainless steel compared with unanodized stainless steel. Such nano-pit surfaces can be designed to support fibroblast growth and, thus, improve the use of 316L stainless steel for various implant applications (such as for enhanced skin healing for amputee devices and for percutaneous implants).

  14. One-dimensional migration of interstitial clusters in SUS316L and its model alloys at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Satoh, Y.; Abe, H.; Matsukawa, Y.; Matsunaga, T.; Kano, S.; Arai, S.; Yamamoto, Y.; Tanaka, N.

    2015-05-01

    For self-interstitial atom (SIA) clusters in various concentrated alloys, one-dimensional (1D) migration is induced by electron irradiation around 300 K. But at elevated temperatures, the 1D migration frequency decreases to less than one-tenth of that around 300 K in iron-based bcc alloys. In this study, we examined mechanisms of 1D migration at elevated temperatures using in situ observation of SUS316L and its model alloys with high-voltage electron microscopy. First, for elevated temperatures, we examined the effects of annealing and short-term electron irradiation of SIA clusters on their subsequent 1D migration. In annealed SUS316L, 1D migration was suppressed and then recovered by prolonged irradiation at 300 K. In high-purity model alloy Fe-18Cr-13Ni, annealing or irradiation had no effect. Addition of carbon or oxygen to the model alloy suppressed 1D migration after annealing. Manganese and silicon did not suppress 1D migration after annealing but after short-term electron irradiation. The suppression was attributable to the pinning of SIA clusters by segregated solute elements, and the recovery was to the dissolution of the segregation by interatomic mixing under electron irradiation. Next, we examined 1D migration of SIA clusters in SUS316L under continuous electron irradiation at elevated temperatures. The 1D migration frequency at 673 K was proportional to the irradiation intensity. It was as high as half of that at 300 K. We proposed that 1D migration is controlled by the competition of two effects: induction of 1D migration by interatomic mixing and suppression by solute segregation.

  15. Comparative study of mechanical properties of 316L stainless steel between traditional production methods and selective laser melting

    NASA Astrophysics Data System (ADS)

    Lackey, Alton Dale

    Additive manufacturing, also known as 3D printing, is a technology which has recently seen expanding use, as well as expansion of the materials and methods able to be used. This thesis looks at the comparison of mechanical properties of 316L stainless steel manufactured by both traditional methods and selective laser melting found by tensile testing. The traditional method used here involved cold rolled 316L steel being machined to the desired part geometry. Selective laser melting used additive manufacturing to produce the parts from powdered 316L stainless steel, doing so in two different build orientations, flat and on edge with regards to the build plate. Solid test specimens, as well as specimens containing a circular stress concentration in the center of the parts, were manufactured and tensile tested. The tensile tests of the specimens were used to find the mechanical properties of the material; including yield strength, ultimate tensile strength (UTS), and Young's modulus of elasticity; where statistical analyses were performed to determine if the different manufacturing processes caused significant differences in the mechanical properties of the material. These analysis consisting of f-tests, to test for variance, and t-test, testing for significant difference of means. Through this study it was found that there were statistically significant differences existing between the mechanical properties of selective laser melting, and its orientations, and cold roll forming of production of parts. Even with a statistical difference, it was found that the results were reasonably close between flat oriented SLM parts and purchased parts. So it can be concluded that, with regards to strength, SLM methods produce parts similar to traditional production methods.

  16. Crack growth behavior of warm-rolled 316L austenitic stainless steel in high-temperature hydrogenated water

    NASA Astrophysics Data System (ADS)

    Choi, Kyoung Joon; Yoo, Seung Chang; Jin, Hyung-Ha; Kwon, Junhyun; Choi, Min-Jae; Hwang, Seong Sik; Kim, Ji Hyun

    2016-08-01

    To investigate the effects of warm rolling on the crack growth of 316L austenitic stainless steel, the crack growth rate was measured and the oxide structure was characterized in high-temperature hydrogenated water. The warm-rolled specimens showed a higher crack growth rate compared to the as-received specimens because the slip bands and dislocations produced during warm rolling served as paths for corrosion and cracking. The crack growth rate increased with the dissolved hydrogen concentration. This may be attributed to the decrease in performance and stability of the protective oxide layer formed on the surface of stainless steel in high-temperature water.

  17. Analysis of structure and deformation behavior of AISI 316L tensile specimens from the second operational target module at the Spallation Neutron Source

    DOE PAGES

    Gussev, Maxim N.; McClintock, David A.; Garner, Frank

    2015-08-05

    In an earlier publication, tensile testing was performed on specimens removed from the first two operational targets of the Spallation Neutron Source (SNS). There were several anomalous features in the results. First, some specimens had very large elongations (up to 57%) while others had significantly smaller values. Second, there was a larger than the usual amount of data scatter in the elongation results. Third, the stress-strain diagrams of nominally similar specimens spanned a wide range of behavior ranging from expected irradiation-induced hardening to varying levels of force drop after yield point and indirect signs of "traveling deformation wave" behavior associatedmore » with strain-induced martensite formation. To investigate the cause(s) of such variable tensile behavior, several specimens from Target 2, spanning the range of observed tensile behavior, were chosen for detailed microstructural examination using electron backscattering analysis (EBSD). It was also shown that the steel employed in the construction of the target contained an unexpected bimodal grain size distribution, containing very large out-of-specification grains surrounded by necklaces of grains of within-specification sizes. The large grains were frequently comparable to the width of the gauge section of the tensile specimen. Moreover, the propensity to form martensite during deformation was shown to be accelerated by radiation but also to be very sensitive to the relative orientation of the grains with respect to the tensile axis. Specimens having large grains in the gauge that were most favorably oriented for production of martensite strongly exhibited the traveling deformation wave phenomenon, while those specimens with less favorably oriented grains had lesser or no degree of the wave effect, thereby accounting for the larger than expected data scatter.« less

  18. Analysis of structure and deformation behavior of AISI 316L tensile specimens from the second operational target module at the Spallation Neutron Source

    SciTech Connect

    Gussev, Maxim N.; McClintock, David A.; Garner, Frank

    2015-08-05

    In an earlier publication, tensile testing was performed on specimens removed from the first two operational targets of the Spallation Neutron Source (SNS). There were several anomalous features in the results. First, some specimens had very large elongations (up to 57%) while others had significantly smaller values. Second, there was a larger than the usual amount of data scatter in the elongation results. Third, the stress-strain diagrams of nominally similar specimens spanned a wide range of behavior ranging from expected irradiation-induced hardening to varying levels of force drop after yield point and indirect signs of "traveling deformation wave" behavior associated with strain-induced martensite formation. To investigate the cause(s) of such variable tensile behavior, several specimens from Target 2, spanning the range of observed tensile behavior, were chosen for detailed microstructural examination using electron backscattering analysis (EBSD). It was also shown that the steel employed in the construction of the target contained an unexpected bimodal grain size distribution, containing very large out-of-specification grains surrounded by necklaces of grains of within-specification sizes. The large grains were frequently comparable to the width of the gauge section of the tensile specimen. Moreover, the propensity to form martensite during deformation was shown to be accelerated by radiation but also to be very sensitive to the relative orientation of the grains with respect to the tensile axis. Specimens having large grains in the gauge that were most favorably oriented for production of martensite strongly exhibited the traveling deformation wave phenomenon, while those specimens with less favorably oriented grains had lesser or no degree of the wave effect, thereby accounting for the larger than expected data scatter.

  19. Analysis of structure and deformation behavior of AISI 316L tensile specimens from the second operational target module at the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    Gussev, M. N.; McClintock, D. A.; Garner, F. A.

    2016-01-01

    In an earlier publication, tensile testing was performed on specimens removed from the first two operational targets of the Spallation Neutron Source (SNS). There were several anomalous features in the results. First, some specimens had very large elongations (up to 57%) while others had significantly smaller values (10-30%). Second, there was a larger than the usual amount of data scatter in the elongation results. Third, the stress-strain diagrams of nominally similar specimens spanned a wide range of behavior ranging from expected irradiation-induced hardening to varying levels of force drop after yield point and indirect signs of "traveling deformation wave" behavior associated with strain-induced martensite formation. To investigate the cause(s) of such variable tensile behavior, several specimens from Target 2, spanning the range of observed tensile behavior, were chosen for detailed microstructural examination using electron backscatter diffraction (EBSD) analysis. It was shown that the steel employed in the construction of the target contained an unexpected bimodal grain size distribution, containing very large out-of-specification grains surrounded by "necklaces" of grains of within-specification sizes. The large grains were frequently comparable to the width of the gauge section of the tensile specimen. The propensity to form martensite during deformation was shown to be accelerated by radiation but also to be very sensitive to the relative orientation of the grains with respect to the tensile axis. Specimens having large grains in the gauge that were most favorably oriented for production of martensite strongly exhibited the traveling deformation wave phenomenon, while those specimens with less favorably oriented grains had lesser or no degree of the wave effect, thereby accounting for the observed data scatter.

  20. Measurement methods for surface oxides on SUS 316L in simulated light water reactor coolant environments using synchrotron XRD and XRF

    NASA Astrophysics Data System (ADS)

    Watanabe, Masashi; Yonezawa, Toshio; Shobu, Takahisa; Shoji, Tetsuo

    2013-03-01

    Synchrotron X-ray diffraction (XRD) and X-ray fluorescent (XRF) measurement techniques have been used for non-destructive characterization of surface oxide films on Type 316L austenitic stainless steels that were exposed to simulated primary water environments of pressurized water reactors (PWR) and boiling water reactors (BWR). The layer structures of the surface spinel oxides were revealed ex situ after oxidation by measurements made as a function of depth. The layer structure of spinel oxides formed in simulated PWR primary water should normally be different from that formed in simulated BWR water. After oxidation in the simulated BWR environment, the spinel oxide was observed to contain NiFe2O4 at shallow depths, and FeCr2O4 and Fe3O4 at deeper depths. By contrast, after oxidation in the simulated PWR primary water environment, a Fe3O4 type spinel was observed near the surface and FeCr2O4 type spinel near the interface with the metal substrate. Furthermore, by in situ measurements during oxidation in the simulated BWR environment, it was also demonstrated that the ratio between spinel and hematite Fe2O3 can be changed depending on the water condition such as BWR normal water chemistry or BWR hydrogen water chemistry.

  1. Surface modification of 316L stainless steel with magnetron sputtered TiN/VN nanoscale multilayers for bio implant applications.

    PubMed

    Subramanian, B; Ananthakumar, R; Kobayashi, Akira; Jayachandran, M

    2012-02-01

    Nanoscale multilayered TiN/VN coatings were developed by reactive dc magnetron sputtering on 316L stainless steel substrates. The coatings showed a polycrystalline cubic structure with (111) preferential growth. XPS analysis indicated the presence of peaks corresponding to Ti2p, V2p, N1s, O1s, and C1s. Raman spectra exhibited the characteristic peaks in the acoustic range of 160-320 cm(-1) and in the optic range between 480 and 695 cm(-1). Columnar structure of the coatings was observed from TEM analysis. The number of adherent platelets on the surface of the TiN/VN multilayer, VN, TiN single layer coating exhibit fewer aggregation and pseudopodium than on substrates. The wear resistance of the multilayer coatings increases obviously as a result of their high hardness. Tafel plots in simulated bodily fluid showed lower corrosion rate for the TiN/VN nanoscale multilayer coatings compared to single layer and bare 316L SS substrate.

  2. Liquid Metal Corrosion of 316L Stainless Steel, 410 Stainless Steel, and 1015 Carbon Steel in a Molten Zinc Bath

    NASA Astrophysics Data System (ADS)

    Xu, Jing; Bright, Mark A.; Liu, Xingbo; Barbero, Ever

    2007-11-01

    Corrosion tests of 1015 low-carbon steel and two stainless steels (410 and 316L) were conducted in a pure zinc bath (99.98 wt pct Zn) in order to better understand the reaction mechanisms that occur during the degradation of submerged hardware at industrial general (batch) galvanizing operations. Through this testing, it was found that, in general, 316L stainless steel showed the best dissolution resistance among these three alloys, while 1015 carbon steel provided a lower solubility than 410 stainless steel. Investigating the failure mechanisms, both metallurgical composition and lattice structure played important roles in the molten metal corrosion behaviors of these alloys. High contents of nickel combined with the influence of chromium improved the resistance to molten zinc corrosion. Moreover, a face-centered-cubic (fcc) structure was more corrosion resistant than body-centered-cubic (bcc) possibly due to the compactness of the atomic structure. Analogously, the body-centered-tetragonal (bct) martensite lattice structure possessed enhanced susceptibility to zinc corrosion as a result of the greater atomic spacing and high strain energy. Finally, an increased bath temperature played an important role in molten metal corrosion by accelerating the dissolution process and changing the nature of intermetallic layers.

  3. Corrosion-erosion test of SS316L grain boundary engineering material (GBEM) in lead bismuth flowing loop

    NASA Astrophysics Data System (ADS)

    Saito, Shigeru; Kikuchi, Kenji; Hamaguchi, Dai; Tezuka, Masao; Miyagi, Masanori; Kokawa, Hiroyuki; Watanabe, Seiichi

    2012-12-01

    To evaluate the lifetime of structural materials utilized in a spallation neutron source, corrosion tests in lead-bismuth eutectic (LBE) have been done at JAEA. Austenitic steels are preferable as the structural material for ADS. However, previous studies have revealed that austenitic steel SS316 shows severe corrosion-erosion in LBE because of LBE penetration through grain boundaries and separation of grains. So it was considered that GBE (grain-boundary engineered) materials may be effective to improve the corrosion resistance of austenitic steels in LBE. In this study, the results of corrosion tests on austenitic steel SS316L-BM (base metal) and SS316L-GBEM (grain-boundary-engineered material) under flowing LBE conditions will be reported. The corrosion test was performed using the JAEA lead-bismuth material corrosion loop (JLBL-1). The experimental conditions were as follows: The high and low temperature parts of the loop were 450 °C and 350 °C, respectively. The flow velocity at the test specimens was about 0.7 m/s. The oxygen concentration in LBE was not controlled and was estimated to have been very low. After the 3600 h of operation, macroscopic, SEM, and SIM observations and EDX analysis were carried out. The results showed that the corrosion depth and LBE penetration through the grain boundaries of the 316SS-GBEM were smaller than those of the 316SS-BM.

  4. Hydrophilic property of 316L stainless steel after treatment by atmospheric pressure corona streamer plasma using surface-sensitive analyses

    NASA Astrophysics Data System (ADS)

    Al-Hamarneh, Ibrahim; Pedrow, Patrick; Eskhan, Asma; Abu-Lail, Nehal

    2012-10-01

    Surgical-grade 316L stainless steel (SS 316L) had its surface hydrophilic property enhanced by processing in a corona streamer plasma reactor using O2 gas mixed with Ar at atmospheric pressure. Reactor excitation was 60 Hz ac high-voltage (0-10 kVRMS) applied to a multi-needle-to-grounded screen electrode configuration. The treated surface was characterized with a contact angle tester. Surface free energy (SFE) for the treated stainless steel increased measurably compared to the untreated surface. The Ar-O2 plasma was more effective in enhancing the SFE than Ar-only plasma. Optimum conditions for the plasma treatment system used in this study were obtained. X-ray photoelectron spectroscopy (XPS) characterization of the chemical composition of the treated surfaces confirms the existence of new oxygen-containing functional groups contributing to the change in the hydrophilic nature of the surface. These new functional groups were generated by surface reactions caused by reactive oxidation of substrate species. Atomic force microscopy (AFM) images were generated to investigate morphological and roughness changes on the plasma treated surfaces. The aging effect in air after treatment was also studied.

  5. Effect of Zr, Nb and Ti addition on injection molded 316L stainless steel for bio-applications: Mechanical, electrochemical and biocompatibility properties.

    PubMed

    Gulsoy, H Ozkan; Pazarlioglu, Serdar; Gulsoy, Nagihan; Gundede, Busra; Mutlu, Ozal

    2015-11-01

    The research investigated the effect of Zr, Nb and Ti additions on mechanical, electrochemical properties and biocompatibility of injection molded 316L stainless steel. Addition of elemental powder is promoted to get high performance of sintered 316L stainless steels. The amount of additive powder plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders used with the elemental Zr, Nb and Ti powders. A feedstock containing 62.5 wt% powders loading was molded at different injection molded temperature. The binders were completely removed from molded components by solvent and thermal debinding at different temperatures. The debinded samples were sintered at 1350°C for 60 min. Mechanical, electrochemical property and biocompatibility of the sintered samples were performed mechanical, electrochemical, SBF immersion tests and cell culture experiments. Results of study showed that sintered 316L and 316L with additives samples exhibited high corrosion properties and biocompatibility in a physiological environment. PMID:26275484

  6. AISI direct steelmaking program

    SciTech Connect

    Aukrust, E.

    1991-01-09

    AISI with co-funding from DOE has initiated a research and development program aimed at the development of a new process for direct steelmaking, and the program is discussed in this document. The project is expected to cost about $30 million over a three-year period, with the government providing approximately 77 percent of the funds and AISI the balance. In contrast to current steelmaking processes which are largely open and batch, the direct steelmaking process would be closed and continuous. Further, it would use coal directly, thereby avoiding the need for coke ovens. The second year of the Direct Steelmaking Program (November 29, 1989, through November 28, 1990) was a year of significant accomplishment. The various research programs proceeded essentially on schedule and the pilot plant, the centerpiece of the program, was completed about three months behind schedule but began operation in almost a picture-perfect manner. This report presents the last years accomplishments.

  7. The Effect of Constant and Pulsed Current Gas Tungsten Arc Welding on Joint Properties of 2205 Duplex Stainless Steel to 316L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Neissi, R.; Shamanian, M.; Hajihashemi, M.

    2016-05-01

    In this study, dissimilar 316L austenitic stainless steel/2205 duplex stainless steel (DSS) joints were fabricated by constant and pulsed current gas tungsten arc welding process using ER2209 DSS as a filler metal. Microstructures and joint properties were characterized using optical and electron scanning microscopy, tensile, Charpy V-notch impact and micro-hardness tests, and cyclic polarization measurements. Microstructural observations confirmed the presence of chromium nitride and delta ferrite in the heat-affected zone of DSS and 316L, respectively. In addition, there was some deviation in the austenite/ferrite ratio of the surface welding pass in comparison to the root welding pass. Besides having lower pitting potential, welded joints produced by constant current gas tungsten arc welding process, consisted of some brittle sigma phase precipitates, which resulted in some impact energy reduction. The tensile tests showed high tensile strength for the weld joints in which all the specimens were broken in 316L base metal.

  8. Effect of relative humidity in high temperature oxidation of ceria nanoparticles coating on 316L austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Giraldez Pizarro, Luis Miguel

    A solution of 20 wt. % colloidal dispersion of Cerium Oxide (CeO2) in 2.5% of acetic acid, was used for depositing a coating film on an austenitic stainless steel 316L. Cerium compounds have been distinguished as potential corrosion inhibitors in coatings over several alloys. The oxidation behavior of the cerium oxide coating on 316L austenitic stainless steel alloy was evaluated in dry and humid environments, the weight changes (W/A) was monitored as a function of time using a custom built Thermogravimetrical Analysis (TGA) instrument at temperatures of 750°C, 800°C and 850°C, and different relative humidity levels (0%, 10% and 20%) respectively. The parabolic oxidation rate and activation energy is calculated experimentally for each relative humidity level. A measurement of the effective diameter size of the ceria nanoparticles was performed using a Light Scattering technique. A characterization of the film morphology and thickness before the oxidation was executed using Atomic Force Microscopy (AFM). Microstructure and chemical composition of the oxidized coated substrates were analyzed using Scanning Electronic Microscopy (SEM) with energy dispersive spectroscopy (EDS). X-Ray Diffractometer (XRD) was used to characterize oxides formed in the surface upon isothermal treatment. A comparison of activation energy values obtained to identify the influence of relative humidity in the oxidation process at high temperature was conducted. Cerium oxides coating may prevent crevice corrosion and increase pitting resistance of 316L relative to the uncoated substrate at high temperatures and different levels of relative humidity acting as a protective oxidation barrier. The calculated parabolic rate constants, kp, at the experimental temperatures tend to increase as a function of humidity levels. The activation energy tends to increase proportionally to higher level of humidity exposures. At 0% relative humidity a value of 319.29 KJ/mol of activation energy is being

  9. Diffusion Bonding Behavior and Characterization of Joints Made Between 316L Stainless Steel Alloy and AZ31 Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Elthalabawy, Waled Mohamed

    The 316L austenitic stainless steel and AZ31 magnesium alloy have physical and mechanical properties which makes these alloys suitable in a number of high technology based industries such as the aerospace and automotive sectors. However, for these alloys to be used in engineering applications, components must be fabricated and joined successfully. The differences in the physical and metallurgical properties between these two alloys prevents the use of conventional fusion welding processes commonly employed in aerospace and transport industry. Therefore, alternative techniques need to be developed and diffusion bonding technology is a process that has considerable potential to join these two dissimilar alloys. In this research work both solid-state and transient liquid phase (TLP) bonding processes were applied. The solid-state bonding of 316L steel to AZ31 magnesium alloy was possible at a bonding temperature of 550°C for 120 minutes using a pressure of 1.3 MPa. The interface characterization of the joint showed a thin intermetallic zone rich in Fe-Al was responsible for providing a metallurgical bond. However, low joint shear strengths were recorded and this was attributed to the poor surface to surface contact. The macro-deformation of the AZ31 alloy prevented the use of higher bonding pressures and longer bonding times. In order to overcome these problems, the TLP bonding process was implemented using pure Cu and Ni foils as interlayers which produced a eutectic phase at the bonding temperature. This research identified the bonding mechanism through microstructural and differential scanning calorimetry investigations. The microstructural characterization of the TLP joints identified intermetallics which became concentrated along the 316L steel/AZ31 bond interface due to the "pushing effect" of the solid/liquid interface during isothermal solidification stage of bonding. The size and concentration of the intermetallics had a noticeable effect on the final joint

  10. CORROSION STUDY FOR THE EFFLUENT TREATMENT FACILITY (ETF) CHROME (VI) REDUCTANT SOLUTION USING 304 & 316L STAINLESS STEEL

    SciTech Connect

    DUNCAN, J.B.

    2007-06-27

    The Effluent Treatment Facility has developed a method to regenerate spent resin from the groundwater pump and treat intercepting chrome(VI) plumes (RPP-RPT-32207, Laboratory Study on Regeneration of Spent DOWEX 21K 16-20 Mesh Ion Exchange Resin). Subsequent laboratory studies have shown that the chrome(VI) may be reduced to chrome(III) by titrating with sodium metabisulfite to an oxidation reduction potential (ORP) of +280 mV at a pH of 2. This test plan describes the use of cyclic potentiodynamic polarization and linear polarization techniques to ascertain the electrochemical corrosion and pitting propensity of the 304 and 316L stainless steel in the acidified reducing the solution that will be contained in either the secondary waste receiver tank or concentrate tank.

  11. Effect of Different Degrees of Sensitization on the EIS Response of 316L and 316 SS in Transpassive Region

    NASA Astrophysics Data System (ADS)

    Morshed Behbahani, K.; Pakshir, M.

    2014-06-01

    Different heat treatments were conducted on 316L and 316 stainless steels, and the sensitized specimens were characterized using anodic polarization and EIS tests in 0.5 M H2SO4 containing 0.01 molar KSCN. The potential ranges related to the transpassive region related to each specimen were determined. The EIS experiments were conducted at different potentials in that region, and the results showed the presence of three different regions, namely the anodic dissolution of the passive layer, dissolution of the grain boundaries, and the occurrence of pitting corrosion owing to the variations in the anodic potential. The higher the applied sensitization temperature, the lower the obtained charge-transfer resistance ( R ct) values, but healing effect was observed at the temperatures above 600 °C for these alloys.

  12. Effect of Temperature on Galling Behavior of SS 316, 316 L and 416 Under Self-Mated Condition

    NASA Astrophysics Data System (ADS)

    Harsha, A. P.; Limaye, P. K.; Tyagi, Rajnesh; Gupta, Ankit

    2016-10-01

    Galling behavior of three different stainless steels (SS 316, 316 L and 416) was evaluated at room temperature and 300 °C under a self-mated condition. An indigenously fabricated galling tester was used to evaluate the galling performance of mated materials as per ASTM G196-08 standard. The variation in frictional torque was recorded online during the test to assess the onset of galling. The galling50 (G50) stress value was used to compare the galling resistance of a combination of materials, and the results indicate a significant influence of temperature on the galling resistance of the materials tested. This has been attributed to the decrease in hardness and yield strength at elevated temperature which results in softening of the steel and limits its ability to resist severe deformation. Scanning electron micrographs of the galled surface reflected a severe plastic deformation in sliding direction, and a typical adhesive wear mechanism is prevalent during the galling process.

  13. Effect of laser shot peening without coating on the surface properties and corrosion behavior of 316L steel

    NASA Astrophysics Data System (ADS)

    Kalainathan, S.; Sathyajith, S.; Swaroop, S.

    2012-12-01

    This paper discusses the results of laser peening without coating on low carbon austenitic stainless steel 316L. Unlike typical experiments on laser peening without coating (LPwC) performed with frequency doubled (green) laser and underwater irradiation, the present study reports LPwC with infrared radiation using thin layer of water as confinement medium. The dependence of laser pulse density on properties such as surface roughness, surface residual stress, microhardness, and corrosion behavior of LPwC specimen were investigated. The magnitude of surface compressive residual stress on laser peened specimen showed appreciable improvement compared to unpeened base material. Microhardness of the specimen improved by 30-40% after LPwC. However, the potentiodynamic polarization study indicated that though there is an enhancement of corrosion potential (Ecorr), the corrosion current density (Icorr) increased with increase in laser pulse density.

  14. Laser surface alloying of 316L stainless steel coated with a bioactive hydroxyapatite-titanium oxide composite.

    PubMed

    Ghaith, El-Sayed; Hodgson, Simon; Sharp, Martin

    2015-02-01

    Laser surface alloying is a powerful technique for improving the mechanical and chemical properties of engineering components. In this study, laser surface irradiation process employed in the surface modification off 316L stainless steel substrate using hydroxyapatite-titanium oxide to provide a composite ceramic layer for the suitability of applying this technology to improve the biocompatibility of medical alloys and implants. Fusion of the metal surface incorporating hydroxyapatite-titania ceramic particles using a 30 W Nd:YAG laser at different laser powers, 40, 50 and 70% power and a scan speed of 40 mm s(-1) was observed to adopt the optimum condition of ceramic deposition. Coatings were evaluated in terms of microstructure, surface morphology, composition biocompatibility using XRD, ATR-FTIR, SEM and EDS. Evaluation of the in vitro bioactivity by soaking the treated metal in SBF for 10 days showed the deposition of biomimetic apatite.

  15. The influence of nanostructured features on bacterial adhesion and bone cell functions on severely shot peened 316L stainless steel.

    PubMed

    Bagherifard, Sara; Hickey, Daniel J; de Luca, Alba C; Malheiro, Vera N; Markaki, Athina E; Guagliano, Mario; Webster, Thomas J

    2015-12-01

    Substrate grain structure and topography play major roles in mediating cell and bacteria activities. Severe plastic deformation techniques, known as efficient metal-forming and grain refining processes, provide the treated material with novel mechanical properties and can be adopted to modify nanoscale surface characteristics, possibly affecting interactions with the biological environment. This in vitro study evaluates the capability of severe shot peening, based on severe plastic deformation, to modulate the interactions of nanocrystallized metallic biomaterials with cells and bacteria. The treated 316L stainless steel surfaces were first investigated in terms of surface topography, grain size, hardness, wettability and residual stresses. The effects of the induced surface modifications were then separately studied in terms of cell morphology, adhesion and proliferation of primary human osteoblasts (bone forming cells) as well as the adhesion of multiple bacteria strains, specifically Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and ampicillin-resistant Escherichia coli. The results indicated a significant enhancement in surface work hardening and compressive residual stresses, maintenance of osteoblast adhesion and proliferation as well as a remarkable decrease in the adhesion and growth of gram-positive bacteria (S. aureus and S. epidermidis) compared to non-treated and conventionally shot peened samples. Impressively, the decrease in bacteria adhesion and growth was achieved without the use of antibiotics, for which bacteria can develop a resistance towards anyway. By slightly grinding the surface of severe shot peened samples to remove differences in nanoscale surface roughness, the effects of varying substrate grain size were separated from those of varying surface roughness. The expression of vinculin focal adhesions from osteoblasts was found to be singularly and inversely related to grain size, whereas the attachment of gram

  16. The influence of nanostructured features on bacterial adhesion and bone cell functions on severely shot peened 316L stainless steel.

    PubMed

    Bagherifard, Sara; Hickey, Daniel J; de Luca, Alba C; Malheiro, Vera N; Markaki, Athina E; Guagliano, Mario; Webster, Thomas J

    2015-12-01

    Substrate grain structure and topography play major roles in mediating cell and bacteria activities. Severe plastic deformation techniques, known as efficient metal-forming and grain refining processes, provide the treated material with novel mechanical properties and can be adopted to modify nanoscale surface characteristics, possibly affecting interactions with the biological environment. This in vitro study evaluates the capability of severe shot peening, based on severe plastic deformation, to modulate the interactions of nanocrystallized metallic biomaterials with cells and bacteria. The treated 316L stainless steel surfaces were first investigated in terms of surface topography, grain size, hardness, wettability and residual stresses. The effects of the induced surface modifications were then separately studied in terms of cell morphology, adhesion and proliferation of primary human osteoblasts (bone forming cells) as well as the adhesion of multiple bacteria strains, specifically Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and ampicillin-resistant Escherichia coli. The results indicated a significant enhancement in surface work hardening and compressive residual stresses, maintenance of osteoblast adhesion and proliferation as well as a remarkable decrease in the adhesion and growth of gram-positive bacteria (S. aureus and S. epidermidis) compared to non-treated and conventionally shot peened samples. Impressively, the decrease in bacteria adhesion and growth was achieved without the use of antibiotics, for which bacteria can develop a resistance towards anyway. By slightly grinding the surface of severe shot peened samples to remove differences in nanoscale surface roughness, the effects of varying substrate grain size were separated from those of varying surface roughness. The expression of vinculin focal adhesions from osteoblasts was found to be singularly and inversely related to grain size, whereas the attachment of gram

  17. The covalent immobilization of heparin to pulsed-plasma polymeric allylamine films on 316L stainless steel and the resulting effects on hemocompatibility.

    PubMed

    Yang, Zhilu; Wang, Jin; Luo, Rifang; Maitz, Manfred F; Jing, Fengjuan; Sun, Hong; Huang, Nan

    2010-03-01

    For an improved hemocompatibility of 316L stainless steel (SS), we develop a facile and effective approach to fabricating a pulsed-plasma polymeric allylamine (P-PPAm) film that possesses a high cross-linking degree and a high density of amine groups, which is used for subsequent bonding of heparin. The P-PPAm film as a stent coating shows good resistance to the deformation behavior of compression and expansion of a stent. Using deionized water as an aging medium, it is demonstrated that the heparin-immobilized P-PPAm (Hep-P-PPAm) surface has a good retention of heparin. The systematic in vitro hemocompatibility evaluation reveals lower platelet adhesion, platelet activation and fibrinogen activation on the Hep-P-PPAm surface, and the activated partial thromboplastin time prolongs for about 15 s compared with 316L SS. The P-PPAm surface significantly promotes adhesion and proliferation of endothelial cells (ECs). For the Hep-P-PPAm, although EC adhesion and proliferation is slightly suppressed initially, after cultivation for 3 days, the growth behavior of ECs is remarkably improved over 316L SS. In vivo results indicate that the Hep-P-PPAm surface successfully restrain thrombus formation by growing a homogeneous and intact shuttle-like endothelium on its surface. The Hep-P-PPAm modified 316L SS shows a promising application for vascular devices.

  18. Effect of dissolved oxygen content on stress corrosion cracking of a cold worked 316L stainless steel in simulated pressurized water reactor primary water environment

    NASA Astrophysics Data System (ADS)

    Zhang, Litao; Wang, Jianqiu

    2014-03-01

    Stress corrosion crack growth tests of a cold worked nuclear grade 316L stainless steel were conducted in simulated pressurized water reactor (PWR) primary water environment containing various dissolved oxygen (DO) contents but no dissolved hydrogen. The crack growth rate (CGR) increased with increasing DO content in the simulated PWR primary water. The fracture surface exhibited typical intergranular stress corrosion cracking (IGSCC) characteristics.

  19. Biofilm initiation and growth of Pseudomonas aeruginosa on 316L stainless steel in low gravity in orbital space flight

    NASA Astrophysics Data System (ADS)

    Todd, Paul; Pierson, Duane L.; Allen, Britt; Silverstein, JoAnn

    The formation of biofilms by water microorganisms such as Pseudomonas aeruginosa in spacecraft water systems has been a matter of concern for long-duration space flight. Crewed spacecraft plumbing includes internal surfaces made of 316L stainless steel. Experiments were therefore undertaken to compare the ability of P. aeruginosa to grow in suspension, attach to stainless steel and to grow on stainless steel in low gravity on the space shuttle. Four categories of cultures were studied during two space shuttle flights (STS-69 and STS-77). Cultures on the ground were held in static horizontal or vertical cylindrical containers or were tumbled on a clinostat and activated under conditions identical to those for the flown cultures. The containers used on the ground and in flight were BioServe Space Technologies’ Fluid Processing Apparatus (FPA), an open-ended test tube with rubber septa that allows robotic addition of bacteria to culture media to initiate experiments and the addition of fixative to conclude experiments. Planktonic growth was monitored by spectrophotometry, and biofilms were characterized quantitatively by epifluorescence and scanning electron microscopy. In these experiments it was found that: (1) Planktonic growth in flown cultures was more extensive than in static cultures, as seen repeatedly in the history of space microbiology, and closely resembled the growth of tumbled cultures. (2) Conversely, the attachment of cells in flown cultures was as much as 8 times that in tumbled cultures but not significantly different from that in static horizontal and vertical cultures, consistent with the notion that flowing fluid reduces microbial attachment. (3) The final surface coverage in 8 days was the same for flown and static cultures but less by a factor of 15 in tumbled cultures, where coverage declined during the preceding 4 days. It is concluded that cell attachment to 316L stainless steel in the low gravity of orbital space flight is similar to that

  20. The Effect of Post-Heat Treatment on Microstructure of 316L Cold-Sprayed Coatings and Their Corrosion Performance

    NASA Astrophysics Data System (ADS)

    Dikici, B.; Yilmazer, H.; Ozdemir, I.; Isik, M.

    2016-04-01

    The combined effects of process gases and post-heat treatment temperature on the microstructure of 316L cold-sprayed coatings on Al5052 substrates have been investigated in this study. The stainless steel coatings were subjected to heat treatment at four different temperatures (250, 500, 750, and 1000 °C) to study the effect of heat treatment. In addition, the corrosion performances of the coatings at different process temperatures have been compared using the potentiodynamic scanning technique. Microstructural characterization of the coatings was carried out using scanning and transmission electron microscopy and x-ray diffraction. The results of present study showed that cold-sprayed stainless steel coatings processed with helium exhibited higher corrosion resistance than those of coatings sprayed with nitrogen process gas. This could partially be attributed to the reduction in porosity level (4.9%) and improvement of particle-particle bonding. In addition, evaluation of the mechanical and microstructural properties of the coatings demonstrated that subsequent heat treatment has major influence on the deposited layers sprayed with He process gas.

  1. Influence of the 316 L stainless steel interface on the stability and barrier properties of plasma fluorocarbon films.

    PubMed

    Lewis, François; Cloutier, Maxime; Chevallier, Pascale; Turgeon, Stéphane; Pireaux, Jean-Jacques; Tatoulian, Michael; Mantovani, Diego

    2011-07-01

    Coatings are known to be one of the more suited strategies to tailor the interface between medical devices and the surrounding cells and tissues once implanted. The development of coatings and the optimization of their adhesion and stability are of major importance. In this work, the influence of plasma etching of the substrate on a plasma fluorocarbon ultrathin coating has been investigated with the aim of improving the stability and the corrosion properties of coated medical devices. The 316 L stainless steel interface was subjected to two different etching sequences prior to the plasma deposition. These plasma etchings, with H(2) and C(2)F(6) as gas precursors, modified the chemical composition and the thickness of the oxide layer and influenced the subsequent polymerization. The coating properties were evaluated using flat substrates submitted to deformation, aging into aqueous medium and corrosion tests. X-ray photoelectron spectroscopy (XPS), time of flight-secondary ion mass spectrometry (ToF-SIMS), ellipsometry, and atomic force microscopy (AFM) were performed to determine the effects of the deformation and the aging on the chemistry and morphology of the coated samples. Analyses showed that plasma etchings were essential to promote reproducible polymerization and film growth. However, the oxide layer thinning due to the etching lowered the corrosion resistance of the substrate and affected the stability of the interface. Still, the deformed samples did not exhibited adhesion and cohesion failure before and after the aging.

  2. Microstructural Variations Across a Dissimilar 316L Austenitic: 9Cr Reduced Activation Ferritic Martensitic Steel Weld Joint

    NASA Astrophysics Data System (ADS)

    Thomas Paul, V.; Karthikeyan, T.; Dasgupta, Arup; Sudha, C.; Hajra, R. N.; Albert, S. K.; Saroja, S.; Jayakumar, T.

    2016-03-01

    This paper discuss the microstructural variations across a dissimilar weld joint between SS316 and 9Cr-RAFM steel and its modifications on post weld heat treatments (PWHT). Detailed characterization showed a mixed microstructure of austenite and martensite in the weld which is in agreement with the phases predicted using Schaeffler diagram based on composition measurements. The presence of very low volume fraction of δ-ferrite in SS316L has been identified employing state of the art electron back-scattered diffraction technique. PWHT of the ferritic steel did not reduce the hardness in the weld metal. Thermal exposure at 973 K (700 °C) showed a progressive reduction in hardness of weld joint with duration of treatment except in austenitic base metal. However, diffusion annealing at 1073 K (800 °C) for 100 hours resulted in an unexpected increase in hardness of weld metal, which is a manifestation of the dilution effects and enrichment of Ni on the transformation characteristics of the weld zone. Migration of carbon from ferritic steel aided the precipitation of fine carbides in the austenitic base metal on annealing at 973 K (700 °C); but enhanced diffusion at 1073 K (880 °C) resulted in coarsening of carbides and thereby reduction of hardness.

  3. Optimization of Process Parameters of Hybrid Laser-Arc Welding onto 316L Using Ensemble of Metamodels

    NASA Astrophysics Data System (ADS)

    Zhou, Qi; Jiang, Ping; Shao, Xinyu; Gao, Zhongmei; Cao, Longchao; Yue, Chen; Li, Xiongbin

    2016-08-01

    Hybrid laser-arc welding (LAW) provides an effective way to overcome problems commonly encountered during either laser or arc welding such as brittle phase formation, cracking, and porosity. The process parameters of LAW have significant effects on the bead profile and hence the quality of joint. This paper proposes an optimization methodology by combining non-dominated sorting genetic algorithm (NSGA-II) and ensemble of metamodels (EMs) to address multi-objective process parameter optimization in LAW onto 316L. Firstly, Taguchi experimental design is adopted to generate the experimental samples. Secondly, the relationships between process parameters ( i.e., laser power ( P), welding current ( A), distance between laser and arc ( D), and welding speed ( V)) and the bead geometries are fitted using EMs. The comparative results show that the EMs can take advantage of the prediction ability of each stand-alone metamodel and thus decrease the risk of adopting inappropriate metamodels. Then, the NSGA-II is used to facilitate design space exploration. Besides, the main effects and contribution rates of process parameters on bead profile are analyzed. Eventually, the verification experiments of the obtained optima are carried out and compared with the un-optimized weld seam for bead geometries, weld appearances, and welding defects. Results illustrate that the proposed hybrid approach exhibits great capability of improving welding quality in LAW.

  4. Reduced platelet adhesion and improved corrosion resistance of superhydrophobic TiO₂-nanotube-coated 316L stainless steel.

    PubMed

    Huang, Qiaoling; Yang, Yun; Hu, Ronggang; Lin, Changjian; Sun, Lan; Vogler, Erwin A

    2015-01-01

    Superhydrophilic and superhydrophobic TiO2 nanotube (TNT) arrays were fabricated on 316L stainless steel (SS) to improve corrosion resistance and hemocompatibility of SS. Vertically-aligned superhydrophilic amorphous TNTs were fabricated on SS by electrochemical anodization of Ti films deposited on SS. Calcination was carried out to induce anatase phase (superhydrophilic), and fluorosilanization was used to convert superhydrophilicity to superhydrophobicity. The morphology, structure and surface wettability of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle goniometry. The effects of surface wettability on corrosion resistance and platelet adhesion were investigated. The results showed that crystalline phase (anatase vs. amorphous) and wettability strongly affected corrosion resistance and platelet adhesion. The superhydrophilic amorphous TNTs failed to protect SS from corrosion whereas superhydrophobic amorphous TNTs slightly improved corrosion resistance of SS. Both superhydrophilic and superhydrophobic anatase TNTs significantly improved corrosion resistance of SS. The superhydrophilic amorphous TNTs minimized platelet adhesion and activation whereas superhydrophilic anatase TNTs activated the formation of fibrin network. On the contrary, both superhydrophobic TNTs (superhydrophobic amorphous TNTs and superhydrophobic anatase TNTs) reduced platelet adhesion significantly and improved corrosion resistance regardless of crystalline phase. Superhydrophobic anatase TNTs coating on SS surface offers the opportunity for the application of SS as a promising permanent biomaterial in blood contacting biomedical devices, where both reducing platelets adhesion/activation and improving corrosion resistance can be effectively combined. PMID:25481855

  5. TEM study of the nucleation of bubbles induced by He implantation in 316L industrial austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Jublot-Leclerc, S.; Lescoat, M.-L.; Fortuna, F.; Legras, L.; Li, X.; Gentils, A.

    2015-11-01

    10 keV He ions were implanted in-situ in a TEM into thin foils of 316L industrial austenitic stainless steel at temperatures ranging from 200 to 550 °C. As a result, overpressurized nanometric bubbles are created with density and size depending strongly on both the temperature and fluence of implantation. An investigation on their nucleation and growth is reported through a rigorous statistical analysis whose procedure, including the consideration of free surface effects, is detailed. In the parameter range considered, the results show that an increase of fluence promotes both the nucleation and growth of the bubbles whilst an increase of temperature enhances the growth of the bubbles at the expense of their nucleation. The confrontation of resulting activation energies with existing models for bubble nucleation enables the identification of the underlying mechanisms. In spite of slight differences resulting from different conditions of implantation among which the He concentration, He production rate and He/dpa ratio, it appears that the dominating mechanisms are the same as those obtained in metals in previous studies, which, in addition to corroborating literature results, shows the suitability of in-situ TEM experiments to simulate the production of helium in nuclear materials.

  6. MC3T3-E1 cell response to stainless steel 316L with different surface treatments.

    PubMed

    Zhang, Hongyu; Han, Jianmin; Sun, Yulong; Huang, Yongling; Zhou, Ming

    2015-11-01

    In the present study, stainless steel 316L samples with polishing, aluminum oxide blasting, and hydroxyapatite (HA) coating were prepared and characterized through a scanning electron microscope (SEM), optical interferometer (surface roughness, Sq), contact angle, surface composition and phase composition analyses. Osteoblast-like MC3T3-E1 cell adhesion on the samples was investigated by cell morphology using a SEM (4h, 1d, 3d, 7d), and cell proliferation was assessed by MTT method at 1d, 3d, and 7d. In addition, adsorption of bovine serum albumin on the samples was evaluated at 1h. The polished sample was smooth (Sq: 1.8nm), and the blasted and HA coated samples were much rougher (Sq: 3.2μm and 7.8μm). Within 1d of incubation, the HA coated samples showed the best cell morphology (e.g., flattened shape and complete spread), but there was no significant difference after 3d and 7d of incubation for all the samples. The absorbance value for the HA coated samples was the highest after 1d and 3d of incubation, indicating better cell viability. However, it reduced to the lowest value at 7d. Protein adsorption on the HA coated samples was the highest at 1h. The results indicate that rough stainless steel surface improves cell adhesion and morphology, and HA coating contributes to superior cell adhesion, but inhibits cell proliferation.

  7. Reduced platelet adhesion and improved corrosion resistance of superhydrophobic TiO₂-nanotube-coated 316L stainless steel.

    PubMed

    Huang, Qiaoling; Yang, Yun; Hu, Ronggang; Lin, Changjian; Sun, Lan; Vogler, Erwin A

    2015-01-01

    Superhydrophilic and superhydrophobic TiO2 nanotube (TNT) arrays were fabricated on 316L stainless steel (SS) to improve corrosion resistance and hemocompatibility of SS. Vertically-aligned superhydrophilic amorphous TNTs were fabricated on SS by electrochemical anodization of Ti films deposited on SS. Calcination was carried out to induce anatase phase (superhydrophilic), and fluorosilanization was used to convert superhydrophilicity to superhydrophobicity. The morphology, structure and surface wettability of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle goniometry. The effects of surface wettability on corrosion resistance and platelet adhesion were investigated. The results showed that crystalline phase (anatase vs. amorphous) and wettability strongly affected corrosion resistance and platelet adhesion. The superhydrophilic amorphous TNTs failed to protect SS from corrosion whereas superhydrophobic amorphous TNTs slightly improved corrosion resistance of SS. Both superhydrophilic and superhydrophobic anatase TNTs significantly improved corrosion resistance of SS. The superhydrophilic amorphous TNTs minimized platelet adhesion and activation whereas superhydrophilic anatase TNTs activated the formation of fibrin network. On the contrary, both superhydrophobic TNTs (superhydrophobic amorphous TNTs and superhydrophobic anatase TNTs) reduced platelet adhesion significantly and improved corrosion resistance regardless of crystalline phase. Superhydrophobic anatase TNTs coating on SS surface offers the opportunity for the application of SS as a promising permanent biomaterial in blood contacting biomedical devices, where both reducing platelets adhesion/activation and improving corrosion resistance can be effectively combined.

  8. Study on cerium-doped nano-TiO2 coatings for corrosion protection of 316 L stainless steel

    NASA Astrophysics Data System (ADS)

    Li, Suning; Wang, Qian; Chen, Tao; Zhou, Zhihua; Wang, Ying; Fu, Jiajun

    2012-04-01

    Many methods have been reported on improving the photogenerated cathodic protection of nano-TiO2 coatings for metals. In this work, nano-TiO2 coatings doped with cerium nitrate have been developed by sol-gel method for corrosion protection of 316 L stainless steel. Surface morphology, structure, and properties of the prepared coatings were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The corrosion protection performance of the prepared coatings was evaluated in 3 wt% NaCl solution by using electrochemical techniques in the presence and absence of simulated sunlight illumination. The results indicated that the 1.2% Ce-TiO2 coating with three layers exhibited an excellent photogenerated cathodic protection under illumination attributed to the higher separation efficiency of electron-hole pairs and higher photoelectric conversion efficiency. The results also showed that after doping with an appropriate concentration of cerium nitrate, the anti-corrosion performance of the TiO2 coating was improved even without irradiation due to the self-healing property of cerium ions.

  9. Microstructural Development and Technical Challenges in Laser Additive Manufacturing: Case Study with a 316L Industrial Part

    NASA Astrophysics Data System (ADS)

    Marya, Manuel; Singh, Virendra; Marya, Surendar; Hascoet, Jean Yves

    2015-08-01

    Additive manufacturing (AM) brings disruptive changes to the ways parts, and products are designed, fabricated, tested, qualified, inspected, marketed, and sold. These changes introduce novel technical challenges and concerns arising from the maturity and diversity of today's AM processes, feedstock materials, and process parameter interactions. AM bears a resemblance with laser and electron beam welding in the so-called conduction mode, which involves a multitude of dynamic physical events between the projected feedstock and a moving heat source that eventually influence AM part properties. For this paper, an air vent was selected for its thin-walled, hollow, and variable cross section, and limited size. The studied air vents, randomly selected from a qualification batch, were fabricated out of 316L stainless steel using a 4 kW fiber laser powder-fed AM system, referred to as construction laser additive direct (CLAD). These were systematically characterized by microhardness indentation, visual examination, optical and scanning electron microscopy, and electron-back-scattering diffraction in order to determine AM part suitability for service and also broadly discuss metallurgical phenomena. The paper then briefly expands the discussion to include additional engineering alloys and further analyze relationships between AM process parameters and AM part properties, consistently utilizing past experience with the same powder-fed CLAD 3D printer, the well-established science and technology of welding and joining, and recent publications on additive manufacturing.

  10. Plasma surface oxidation of 316L stainless steel for improving adhesion strength of silicone rubber coating to metal substrate

    NASA Astrophysics Data System (ADS)

    Latifi, Afrooz; Imani, Mohammad; Khorasani, Mohammad Taghi; Daliri Joupari, Morteza

    2014-11-01

    Stainless steel 316L is one of the most widely used materials for fabricating of biomedical devices hence, improving its surface properties is still of great interest and challenging in biomaterial sciences. Plasma oxidation, in comparison to the conventional chemical or mechanical methods, is one of the most efficient methods recently used for surface treatment of biomaterials. Here, stainless steel specimens were surface oxidized by radio-frequency plasma irradiation operating at 34 MHz under pure oxygen atmosphere. Surface chemical composition of the samples was significantly changed after plasma oxidation by appearance of the chromium and iron oxides on the plasma-oxidized surface. A wettable surface, possessing high surface energy (83.19 mN m-1), was observed after plasma oxidation. Upon completion of the surface modification process, silicone rubber was spray coated on the plasma-treated stainless steel surface. Morphology of the silicone rubber coating was investigated by scanning electron microscopy (SEM). A uniform coating was formed on the oxidized surface with no delamination at polymer-metal interface. Pull-off tests showed the lowest adhesion strength of coating to substrate (0.12 MPa) for untreated specimens and the highest (0.89 MPa) for plasma-oxidized ones.

  11. The role of deformation mechanisms in flow localization of 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Wu, Xianglin; Pan, Xiao; Mabon, James C.; Li, Meimei; Stubbins, James F.

    2006-09-01

    Type 316 SS is widely used as a structural material in a variety of current accelerator driven systems and designs as well as in a number of current and advanced fission and fusion reactor concepts. The material is found to be very sensitive to irradiation damage in the temperature range of 150-400 °C, where low levels of irradiation exposure, as little as 0.1 dpa, can substantially reduce the uniform elongation in tensile tests. This process, where the plastic flow becomes highly localized resulting in very low overall ductility, is referred to as flow localization. The process controlling this restriction of flow is related to the difference between the yield and ultimate strengths such that dramatic irradiation-induced increases in the yield strength results in very limited plastic flow until necking. In this study, the temperature dependence of this process is examined in light of the operating deformation mechanisms. It is found that twinning is an important deformation mechanism at lower temperatures but is not available in the temperature range of concern since the stress to activate twinning becomes excessively high. This limits the deformation and leads to the flow localization process.

  12. A study of Ta xC 1 -x coatings deposited on biomedical 316L stainless steel by radio-frequency magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Ding, M. H.; Wang, B. L.; Li, L.; Zheng, Y. F.

    2010-11-01

    In this paper, Ta xC 1 -x coatings were deposited on 316L stainless steel (316L SS) by radio-frequency (RF) magnetron sputtering at various substrate temperatures ( Ts) in order to improve its corrosion resistance and hemocompatibility. XRD results indicated that Ts could significantly change the microstructure of Ta xC 1 -x coatings. When Ts was <150 °C, the Ta xC 1 -x coatings were in amorphous condition, whereas when Ts was ≥150 °C, TaC phase was formed, exhibiting in the form of particulates with the crystallite sizes of about 15-25 nm ( Ts = 300 °C). Atomic force microscope (AFM) results showed that with the increase of Ts, the root-mean-square (RMS) values of the Ta xC 1 -x coatings decreased. The nano-indentation experiments indicated that the Ta xC 1 -x coating deposited at 300 °C had a higher hardness and modulus. The scratch test results demonstrated that Ta xC 1 -x coatings deposited above 150 °C exhibited good adhesion performance. Tribology tests results demonstrated that Ta xC 1 -x coatings exhibited excellent wear resistance. The results of potentiodynamic polarization showed that the corrosion resistance of the 316L SS was improved significantly because of the deposited Ta xC 1 -x coatings. The platelet adhesion test results indicated that the Ta xC 1 -x coatings deposited at Ts of 150 °C and 300 °C possessed better hemocompatibility than the coating deposited at Ts of 25 °C. Additionally, the hemocompatibility of the Ta xC 1 -x coating on the 316L SS was found to be influenced by its surface roughness, hydrophilicity and the surface energy.

  13. Multilayered Zr-C/a-C film on stainless steel 316L as bipolar plates for proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Bi, Feifei; Peng, Linfa; Yi, Peiyun; Lai, Xinmin

    2016-05-01

    A multilayered zirconium-carbon/amorphous carbon (Zr-C/a-C) coating is synthesized by magnetron sputtering in order to improve the corrosion resistance and interfacial conductivity of stainless steel 316L (SS316L) as bipolar plates for proton exchange membrane fuel cells (PEMFCs). Zr-C/a-C film contains an outmost pure amorphous carbon layer and a sub zirconium containing carbon layer. Interfacial contact resistance (ICR) between carbon paper and coated SS316L decreases to 3.63 mΩ cm2 at 1.4 MPa. Potentiodynamic polarization results reveal that the corrosion potential of Zr-C/a-C coated sample is more positive than pure a-C coated sample and the current density is only 0.49 μA cm-2 at the cathode applied potential 0.6 V. Electrochemical impendence spectroscopy also indicates that multilayered Zr-C/a-C film coated SS316L has much higher charge transfer resistance than the bare sample. After potentiostatic polarization, ICR values are 3.92 mΩ cm2 and 3.82 mΩ cm2 in the simulated PEMFCs cathode and anode environment, respectively. Moreover, XPS analysis of the coated samples before and after potential holding tests shows little difference, which disclose the chemical stability of multilayered Zr-C/a-C film. Therefore, the multilayered Zr-C/a-C coating exhibits excellent performance in various aspects and is preferred for the application of stainless steel bipolar plates.

  14. COMPUTATION MODELING OF LOCALIZED CORROSION STABILITY ON WETTED SS316L AT 25 AND 95 DEGREE C

    SciTech Connect

    F. Cuti; F.J. Presuel-Moreno; R.G. Kelly

    2005-10-13

    For corrosion resistant materials exposed to low-temperature atmospheric environments, the corrosion mode of highest risk is expected to be localized corrosion (pitting, crevice, stress-corrosion cracking) due to accumulation of aggressive species within thin solution layers and/or formation of occluded local geometries. The stability of such a localized corrosion site requires that the corroding site (anode) must dissolve at a sufficient high rate to maintain the critical chemistry, and a robust cathodic area (cathode) must exist that can provide sufficient cathodic current. The characteristics of both the anode and the cathode depend on a large number of physiochemical variables (e.g., temperature, ionic concentration, water layer thickness, etc) and electrochemical parameters (i.e., cathodic and anodic polarization behavior). The effects of all these parameters add significantly to the dimensionality of the problem and a systematic study of these parameters is thus more tractable computationally than experimentally. The objective of this study was to computationally characterize the stability of such a local corrosion site and explore the effects of physiochemical and electrochemical parameters on that stability. The overall goal is to contribute to the establishment of a scientific basis for the prediction of the stabilization of localized attack on wetted, corrosion resistant material surface. A localized corrosion site, illustrated in Figure 1, consists of two parts: (a) the external wetted surface (cathode) and (b) the crevice (anode). This study computationally separated the two and modeled them individually, linking them through the imposition of a common fixed potential at the junction point (i.e., the mouth of the crevice). An objected-oriented computational code, CREVICER, developed at UVa, was extended to study separately both the wet surface (cathode) and the crevice (anode). SS316L was chosen as the material of interest.

  15. A progress report on the use of electrochemical noise to investigate the effects of zebra mussel attachment on the corrosion resistance of AISI Type 304 stainless steel and carbon steel in lake water

    SciTech Connect

    Brennenstuhl, A.M.; Sim, B.; Claudi, R.

    1996-12-31

    The electrochemical noise technique was used to determine the effect of zebra mussel settlement on the corrosion performance of AISI Type 304 stainless steel and carbon steel (ASTM A53 Grade B). These materials represent alloys commonly used for handling untreated Great Lakes water at Ontario Hydro`s power generating plants. This work was motivated by a concern that zebra mussel settlement will lead to accelerated attack of these materials as a result of the establishment of stable crevice conditions and the growth of corrosion influencing anaerobic sulfate-reducing bacteria (SRB). Corrosion monitoring was carried out in a field test facility that uses the same untreated Lake Erie water as Ontario Hydro`s Nanticoke Thermal Generating Station. The test program extended from May through December 1993. During this period, a number of electrochemical parameters were monitored simultaneously, including coupling current, electrochemical potential noise (EPN), electrochemical current noise (ECN), degree of localization (DoL), and resistance noise (R{sub n}). Differences were observed in the performance of the control samples and the samples to which mussels were attached. The results for the AISI Type 304 stainless steel suggested that over the period monitored, mussel attachment reduced corrosion activity. Similarly, signals from carbon steel, samples exposed to mussels, although initially displaying relatively high corrosion rates, exhibited less corrosion damage than did control samples over the longer term. The reason for this difference in performance is not known but is considered to have resulted from a change in the surface environment as a result of mussel attachment, which appeared to diminish corrosion. One possible explanation may be the generation of inhibitive species by the mussels.

  16. In-vitro bioactivity, biocorrosion and antibacterial activity of silicon integrated hydroxyapatite/chitosan composite coating on 316 L stainless steel implants.

    PubMed

    Sutha, S; Kavitha, K; Karunakaran, G; Rajendran, V

    2013-10-01

    A simple and effective ultrasonication method was applied for the preparation of 0, 0.4, 0.8, 1.0 and 1.6 wt% silicon substituted hydroxyapatite (HAp) (SH). The Ca/P ratio of the synthesised SH nanoparticles were in the range of 1.58-1.70. Morphological changes were noticed in HAp with respect to the amount of Si from 0 to 1.6 wt%. The morphology of the particles changed from spherical shape to rod-like morphology with respect to the amount of Si which was confirmed using transmission electron microscopy. X-ray diffraction studies confirm the formation of phase pure SH nanoparticles without any secondary phase. Chitosan (CTS) blended SH nanocomposites coating on surgical grade 316 L stainless steel (316 L SS) implant was made by spin coating technique. The surface of the coated implant was characterised using scanning electron microscopy which confirms the uniform coating without cracks and pores. The increased corrosion resistance of the 1.6 wt% of SH/CTS-coated SS implant in the simulated body fluid (SBF) indicates the long-term biostability of SH composite-coated ceramics in vitro than the 0 wt% SH/CTS. The testing of SH/CTS nanocomposites with gram-positive and gram-negative bacterial strains confirms that the antibacterial ability improves with the higher substitution of Si. In addition, formation of bone-like apatite layer on the SH/CTS-coated implant in SBF was studied through SEM analysis and it confirms the ability to increase the HAp formation on the surface of 1.0 wt% SH/CTS-coated 316 L SS implant.

  17. In-vitro bioactivity, biocorrosion and antibacterial activity of silicon integrated hydroxyapatite/chitosan composite coating on 316 L stainless steel implants.

    PubMed

    Sutha, S; Kavitha, K; Karunakaran, G; Rajendran, V

    2013-10-01

    A simple and effective ultrasonication method was applied for the preparation of 0, 0.4, 0.8, 1.0 and 1.6 wt% silicon substituted hydroxyapatite (HAp) (SH). The Ca/P ratio of the synthesised SH nanoparticles were in the range of 1.58-1.70. Morphological changes were noticed in HAp with respect to the amount of Si from 0 to 1.6 wt%. The morphology of the particles changed from spherical shape to rod-like morphology with respect to the amount of Si which was confirmed using transmission electron microscopy. X-ray diffraction studies confirm the formation of phase pure SH nanoparticles without any secondary phase. Chitosan (CTS) blended SH nanocomposites coating on surgical grade 316 L stainless steel (316 L SS) implant was made by spin coating technique. The surface of the coated implant was characterised using scanning electron microscopy which confirms the uniform coating without cracks and pores. The increased corrosion resistance of the 1.6 wt% of SH/CTS-coated SS implant in the simulated body fluid (SBF) indicates the long-term biostability of SH composite-coated ceramics in vitro than the 0 wt% SH/CTS. The testing of SH/CTS nanocomposites with gram-positive and gram-negative bacterial strains confirms that the antibacterial ability improves with the higher substitution of Si. In addition, formation of bone-like apatite layer on the SH/CTS-coated implant in SBF was studied through SEM analysis and it confirms the ability to increase the HAp formation on the surface of 1.0 wt% SH/CTS-coated 316 L SS implant. PMID:23910313

  18. High-Temperature Oxidation Resistance of a Nanoceria Spray-Coated 316L Stainless Steel Under Short-Term Air Exposure

    NASA Astrophysics Data System (ADS)

    Lopez, Hugo F.; Mendoza, Humberto; Church, Ben

    2013-10-01

    Nanoceria coatings using a spray method were implemented on a 316L stainless steel (SS). Coated and uncoated coupons were exposed to dry air at 1073 K to 1273 K (800 °C to 1000 °C) for short time periods (up to 24 hours) and in situ measurements of oxidation were carried out using a highly sensitive thermogravimetric balance. From the experimental outcome, activation energies were determined in both, coated and uncoated 316 SS coupons. The estimated exhibited activation energies for oxidation in the coated and uncoated conditions were 174 and 356 kJ/mol, respectively. In addition, the developed scales were significantly different. In the coated steel, the dominant oxide was an oxide spinel (Fe, Mn)3O4 and the presence of Fe2O3 was sharply reduced, particularly at 1273 K (1000 °C). In contrast, no spinel was found in the uncoated 316L SS, and Fe2O3 was always present in the scale at all the investigated oxidation temperatures. The coated steels developed a highly adherent fine-grained scale structure. Apparently, the nanoceria particles enhanced nucleation of the newly formed scale while restricting coarsening. Coarse grain structures were found in the uncoated steels with scale growth occurring at grain ledges. Moreover, the oxidation rates for the coated 316L SS were at least an order of magnitude lower than those exhibited by the steel in the uncoated condition. The reduction in oxidation rates is attributed to a shift in the oxidation mechanism from outward cation diffusion to inward oxygen diffusion.

  19. Effect of Heat Treatment on the Microstructure and Mechanical Properties of Stainless Steel 316L Coatings Produced by Cold Spray for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    AL-Mangour, Bandar; Vo, Phuong; Mongrain, Rosaire; Irissou, Eric; Yue, Stephen

    2014-04-01

    In this study, the effects of heat treatment on the microstructure and mechanical properties of cold sprayed stainless steel 316L coatings using N2 and He as propellant gases were investigated. Powder and coating characterizations, including coating microhardness, coating porosity, and XRD phase analysis were performed. It was found that heat treatment reduced porosity, improved inter-particle bonding, and increased ductility. XRD results confirmed that no phase transformation occurred during deposition. Significant increase in UTS and ductility was observed for the annealed specimens obtained with nitrogen propellant, whereas little changes were observed for the helium propellant produced specimen.

  20. Laser surface texturing of 316L stainless steel in air and water: A method for increasing hydrophilicity via direct creation of microstructures

    NASA Astrophysics Data System (ADS)

    Razi, Sepehr; Madanipour, Khosro; Mollabashi, Mahmoud

    2016-06-01

    Laser processing of materials in water contact is sometimes employed for improving the machining, cutting or welding quality. Here, we demonstrate surface patterning of stainless steel grade 316L by nano-second laser processing in air and water. Suitable adjustments of laser parameters offer a variety of surface patterns on the treated targets. Furthermore alterations of different surface features such as surface chemistry and wettability are investigated in various processing circumstances. More than surface morphology, remarkable differences are observed in the surface oxygen content and wettability of the samples treated in air and water at the same laser processing conditions. Mechanisms of the changes are discussed extensively.

  1. Reactive Wetting of an Iron-Base Superalloy MSA2020 and 316L Stainless Steel by Molten Zinc-Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Xu, Jing; Liu, Xingbo; Bright, Mark A.; Hemrick, James G.; Sikka, Vinod; Barbero, Ever

    2008-06-01

    The reactive wetting behaviors of MSA2020, an Fe-based superalloy, and 316L stainless steel in contact with a molten Zn-Al alloy were investigated by the sessile drop method. This investigation led to the following findings. (1) 316L not only suffered considerable wetting, but also reacted with the molten Zn-Al alloy at a higher rate than MSA2020. (2) The contact angle of MSA2020 wet by the molten Zn-Al alloy dropped to an acute angle when the temperature was increased to 500 °C. (3) The surface reaction was found to initiate even though the liquid droplet and substrate were observed as nonwetting (contact angle larger than 90 deg). (4) The reaction mechanisms were identified in three stages. Initially, the Al diffused into the substrate to form an Fe-aluminide layer, which acted as the reaction front. Next, the reaction front penetrated the substrate through inward diffusion of Al. Finally, Zn-rich zones formed behind the reaction front as a result of Al depletion. (5) The alloying constituents (W, Mo, and Cr) in MSA2020 stably segregating on the surface reduced the wettability by molten Zn-Al by covering the reactive sites on the solid-liquid interface.

  2. Electrochemical behavior of nanocrystalline Ta/TaN multilayer on 316L stainless steel: Novel bipolar plates for proton exchange membrane fuel-cells

    NASA Astrophysics Data System (ADS)

    Alishahi, M.; Mahboubi, F.; Mousavi Khoie, S. M.; Aparicio, M.; Hübner, R.; Soldera, F.; Gago, R.

    2016-08-01

    Insufficient corrosion resistance and surface conductivity are two main issues that plague large-scale application of stainless steel (SS) bipolar plates in proton exchange membrane fuel cells (PEMFCs). This study explores the use of nanocrystalline Ta/TaN multilayer coatings to improve the electrical and electrochemical performance of polished 316L SS bipolar plates. The multilayer coatings have been deposited by (reactive) magnetron sputtering and characterized by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy. The electrochemical behavior of bare and coated substrates has been evaluated in simulated PEMFC working environments by potentiodynamic and potentiostatic polarization tests at ambient temperature and 80 °C. The results show that the Ta/TaN multilayer coating increases the polarization resistance of 316L SS by about 30 and 104 times at ambient and elevated temperatures, respectively. The interfacial contact resistance (ICR) shows a low value of 12 mΩ × cm2 before the potentiostatic test. This ICR is significantly lower than for the bare substrate and remains mostly unchanged after potentiostatic polarization for 14 h. In addition, the high contact angle (92°) with water for coated substrates indicates a hydrophobic character, which can improve the water management within the cell in PEMFC stacks.

  3. Surface fatigue and failure characteristics of hot-forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.

    1987-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground AISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  4. Surface fatigue and failure characteristics of hot forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.

    1986-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground SISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  5. Influence of Explosive-Driven Shock Prestraining on the Microstructural Evolution and Shear Localization of 304 and 316L Stainless Steels

    SciTech Connect

    Xue Qing; Cerreta, Ellen K.; Gray, George T. III

    2006-07-28

    Initiation and development of adiabatic shear bands in explosively pre-shocked 304 and 316L stainless steels was investigated to quantify the influence of shock prestraining on the onset of shear localization. Forced shear tests on hat-shaped specimens were conducted using a compressive split-Hopkinson pressure bar. The shear localized behavior under the forced shear condition in these preshocked materials was examined. Shear-band initiation was found to be very sensitive to the preshocked microstructures, especially to the strong interactions among defects such as deformation twin networks. The microstructures of shear bands were characterized using transmission electron microscopy(TEM). Dynamic and quasi-static recovery was verified to be a dominant mechanism in the formation of the ultra fine substructures within the shear bands generated in these preshocked steels.

  6. Evaluation of the Effect of Dynamic Sodium on the Low Cycle Fatigue Properties of 316L(N) Stainless Steel Base and Weld Joints

    NASA Astrophysics Data System (ADS)

    Ganesan, V.; Kannan, R.; Mariappan, K.; Sukumaran, G.; Sandhya, R.; Rao, K. Bhanu Sankara

    2012-06-01

    Low cycle fatigue (LCF) tests on 316L(N) austenitic stainless steel base and weld joints were at 823 K and 873 K at a constant strain rate of 3 × 10 -3 s -1 with strain ranges varying from {±}0.4% to {±}1.0% in a servo-hydraulic fatigue test system under flowing sodium environment. The cyclic stress response exhibited a similar trend as that in air comprising of an initial rapid hardening, followed by a slight softening stage before saturation. The fatigue lives are significantly improved in sodium environment when compared to identical testing conditions in air environment. The lack of oxidation in sodium environment is attributed to the delayed crack initiation, reduced crack propagation rate and consequent increase in fatigue life. Comparison of the data evaluated in sodium with RCC-MR design code, derived on the basis of data obtained from air shows that the design based on air tests is conservative.

  7. Corrosion behavior of TiN, TiAlN, TiAlSiN-coated 316L stainless steel in simulated proton exchange membrane fuel cell environment

    NASA Astrophysics Data System (ADS)

    Nam, Nguyen Dang; Vaka, Mahesh; Tran Hung, Nguyen

    2014-12-01

    To gain high hardness, good thermal stability and corrosion resistance, multicomponent TiAlSiN coating has been developed using different deposition methods. In this study, the influence of Al and Si on the electrochemical properties of TiN-coated 316L stainless steel as bipolar plate (BP) materials has been investigated in simulated proton exchange membrane fuel cell environment. The deposited TiN, TiAlN and TiAlSiN possess high hardness of 23.9, 31.7, 35.0 GPa, respectively. The coating performance of the TiN coating is enhanced by Al and Si addition due to lower corrosion current density and higher Rcoating and Rct values. This result could be attributed to the formation of crystalline-refined TiN(200), which improves the surface roughness, surface resistance, corrosion performance, and decreased passive current density.

  8. Electropolishing of Re-melted SLM Stainless Steel 316L Parts Using Deep Eutectic Solvents: 3 × 3 Full Factorial Design

    NASA Astrophysics Data System (ADS)

    Alrbaey, K.; Wimpenny, D. I.; Al-Barzinjy, A. A.; Moroz, A.

    2016-07-01

    This three-level three-factor full factorial study describes the effects of electropolishing using deep eutectic solvents on the surface roughness of re-melted 316L stainless steel samples produced by the selective laser melting (SLM) powder bed fusion additive manufacturing method. An improvement in the surface finish of re-melted stainless steel 316L parts was achieved by optimizing the processing parameters for a relatively environmentally friendly (`green') electropolishing process using a Choline Chloride ionic electrolyte. The results show that further improvement of the response value-average surface roughness ( Ra) can be obtained by electropolishing after re-melting to yield a 75% improvement compared to the as-built Ra. The best Ra value was less than 0.5 μm, obtained with a potential of 4 V, maintained for 30 min at 40 °C. Electropolishing has been shown to be effective at removing the residual oxide film formed during the re-melting process. The material dissolution during the process is not homogenous and is directed preferentially toward the iron and nickel, leaving the surface rich in chromium with potentially enhanced properties. The re-melted and polished surface of the samples gave an approximately 20% improvement in fatigue life at low stresses (approximately 570 MPa). The results of the study demonstrate that a combination of re-melting and electropolishing provides a flexible method for surface texture improvement which is capable of delivering a significant improvement in surface finish while holding the dimensional accuracy of parts within an acceptable range.

  9. Comparison of pitting fatigue life of ausforged and standard forged AISI M-50 and AISI 9310 spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Bamberger, E. N.; Zaretsky, E. V.

    1975-01-01

    Standard forged and ausforged spur gears made of vacuum-induction-melted, consumable-electrode, vacuum-arc-remelted AISI M-50 steel were tested under conditions that produced fatigue pitting. The gears were 8.89 cm (3.5 in.) in pitch diameter and had tip relief. The M-50 standard forged and ausforged test results were compared with each other. They were then compared with results for machined vacuum-arc-remelted AISI 9310 gears tested under identical conditions. Both types of M-50 gears had lives approximately five times that of the 9310 gears. The life at which 10 percent of the M-50 ausforged gears failed was slightly less than that at which the M-50 standard forged gears failed. The ausforged gears had a slightly greater tendency to fail by tooth fracture than did the standard forged gears, most likely because of the better forging and grain flow pattern of standard forged gears.

  10. SU-E-T-548: Modeling of Breast IORT Using the Xoft 50 KV Brachytherapy Source and 316L Steel Rigid Shield

    SciTech Connect

    Burnside, W

    2015-06-15

    Purpose: Xoft provides a set of 316L Stainless Steel Rigid Shields to be used with their 50 kV X-ray source for Breast IORT treatments. Modeling the different shield sizes in MCNP provides information to help make clinical decisions for selecting the appropriate shield size. Methods: The Xoft Axxent 50 kV Electronic Brachytherapy System has several applications in radiation therapy, one of which is treating cancer of the breast intraoperatively by placing the miniaturized X-ray tube inside an applicator balloon that is expanded to fill the lumpectomy bed immediately following tumor removal. The ribs, lung, and muscular chest wall are all regions at risk to receive undesired dose during the treatment. A Xoft 316L Stainless Steel Rigid Shield can be placed between the intracostal muscles of the chest wall and the remaining breast tissue near the balloon to attenuate the beam and protect these organs. These shields are provided in 5 different sizes, and the effects on dose to the surrounding tissues vary with shield size. MCNP was used to model this environment and tally dose rate to certain regions of interest. Results: The average rib dose rate calculated using 0cm (i.e., no shield), 3cm, and 5cm diameter shields were 26.89, 15.43, and 8.91 Gy/hr respectively. The maximum dose rates within the rib reached 94.74 Gy/hr, 53.56 Gy/hr, and 31.44 Gy/hr for the 0cm, 3cm, and 5cm cases respectively. The shadowing effect caused by the steel shields was seen in the 3-D meshes and line profiles. Conclusion: This model predicts a higher dose rate to the underlying rib region with the 3cm shield compared to the 5cm shield; it may be useful to select the largest possible diameter when choosing a shield size for a particular IORT patient. The ability to attenuate the beam to reduce rib dose was also confirmed. Research sponsored by Xoft Inc, a subsidiary of iCAD.

  11. Laser Surface Hardening of AISI 1045 Steel

    NASA Astrophysics Data System (ADS)

    Li, Ruifeng; Jin, Yajuan; Li, Zhuguo; Qi, Kai

    2014-09-01

    The study investigates laser surface hardening in the AISI 1045 steel using two different types of industrial laser: a high-power diode laser (HPDL) and a CO2 laser, respectively. The effect of process parameters such as beam power, travel speed on structure, case depth, and microhardness was examined. In most cases, a heat-affected zone (HAZ) formed below the surface; a substantial increase in surface hardness was achieved. In addition, big differences were found between the hardened specimens after HPDL surface hardening and CO2 laser surface hardening. For HPDL, depths of the HAZ were almost equal in total HAZ o, without surface melting. For CO2 laser, the depths changed a lot in the HAZ, with surface melting in the center. To better understand the difference of laser hardening results when use these two types of laser, numerical (ANSYS) analysis of the heat conduction involved in the process was also studied. For HPDL method, a rectangular beam spot and uniform energy distribution across the spot were assumed, while for CO2 laser, a circular beam spot and Gaussian energy distribution were assumed. The results showed that the energy distribution variety altered the thermal cycles of the HAZ dramatically. The rectangular HPDL laser beam spot with uniform energy distribution is much more feasible for laser surface hardening.

  12. Effects of Ag and Cu ions on the microbial corrosion of 316L stainless steel in the presence of Desulfovibrio sp.

    PubMed

    Unsal, Tuba; Ilhan-Sungur, Esra; Arkan, Simge; Cansever, Nurhan

    2016-08-01

    The utilization of Ag and Cu ions to prevent both microbial corrosion and biofilm formation has recently increased. The emphasis of this study lies on the effects of Ag and Cu ions on the microbial corrosion of 316L stainless steel (SS) induced by Desulfovibrio sp. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to analyze the corrosion behavior. The biofilm formation, corrosion products and Ag and Cu ions on the surfaces were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and elemental mapping. Through circuit modeling, EIS results were used to interpret the physicoelectric interactions between the electrode, biofilm and culture interfaces. EIS results indicated that the metabolic activity of Desulfovibrio sp. accelerated the corrosion rate of SS in both conditions with and without ions. However, due to the retardation in the growth of Desulfovibrio sp. in the presence of Ag and Cu ions, significant decrease in corrosion rate was observed in the culture with the ions. In addition, SEM and EIS analyses revealed that the presence of the ions leads to the formation on the SS of a biofilm with different structure and morphology. Elemental analysis with EDS detected mainly sulfide- and phosphorous-based corrosion products on the surfaces. PMID:27105168

  13. Interfacial characterization of SLM parts in multi-material processing: Metallurgical diffusion between 316L stainless steel and C18400 copper alloy

    SciTech Connect

    Liu, Z.H. Zhang, D.Q. Sing, S.L. Chua, C.K. Loh, L.E.

    2014-08-15

    Multi-material processing in selective laser melting using a novel approach, by the separation of two different materials within a single dispensing coating system was investigated. 316L stainless steel and UNS C18400 Cu alloy multi-material samples were produced using selective laser melting and their interfacial characteristics were analyzed using focused ion beam, scanning electron microscopy, energy dispersive spectroscopy and electron back scattered diffraction techniques. A substantial amount of Fe and Cu element diffusion was observed at the bond interface suggesting good metallurgical bonding. Quantitative evidence of good bonding at the interface was also obtained from the tensile tests where the fracture was initiated at the copper region. Nevertheless, the tensile strength of steel/Cu SLM parts was evaluated to be 310 ± 18 MPa and the variation in microhardness values was found to be gradual along the bonding interface from the steel region (256 ± 7 HV{sub 0.1}) to the copper region (72 ± 3 HV{sub 0.1}). - Highlights: • Multi-material processing was successfully implemented and demonstrated in SLM. • Bi-metallic laminates of steel/Cu were successfully produced with the SLM process. • A substantial amount of Fe and Cu diffusion was observed at the bond interface. • Good metallurgical bonding was obtained at the interface of the steel/Cu laminates. • Highly refined microstructure was obtained due to rapid solidification in SLM.

  14. Comparison between Palm Oil Derivative and Commercial Thermo-Plastic Binder System on the Properties of the Stainless Steel 316L Sintered Parts

    NASA Astrophysics Data System (ADS)

    Ibrahim, R.; Azmirruddin, M.; Wei, G. C.; Fong, L. K.; Abdullah, N. I.; Omar, K.; Muhamad, M.; Muhamad, S.

    2010-03-01

    Binder system is one of the most important criteria for the powder injection molding (PIM) process. Failure in the selection of the binder system will affect on the final properties of the sintered parts. The objectives of this studied is to develop a novel binder system based on the local natural resources and environmental friendly binder system from palm oil derivative which is easily available and cheap in our country of Malaysia. The novel binder that has been developed will be replaced the commercial thermo-plastic binder system or as an alternative binder system. The results show that the physical and mechanical properties of the final sintered parts fulfill the Metal Powder Industries Federation (MPIF) standard 35 for PIM parts. The biocompatibility test using cell osteosarcoma (MG63) and vero fibroblastic also shows that the cell was successfully growth on the sintered stainless steel 316L parts indicate that the novel binder was not toxic. Therefore, the novel binder system based on palm oil derivative that has been developed as a binder system fulfills the important criteria for the binder system in PIM process.

  15. Influence of LBE long term exposure and simultaneous fast neutron irradiation on the mechanical properties of T91 and 316L

    NASA Astrophysics Data System (ADS)

    Stergar, E.; Eremin, S. G.; Gavrilov, S.; Lambrecht, M.; Makarov, O.; Iakovlev, V.

    2016-05-01

    The LEXUR-II-LBE irradiation campaign was conducted from 2011 to 2012 and was aimed to investigate the combined influence of irradiation and LBE environment. In this irradiation campaign tensile test samples, pressurized tubes and corrosion samples were irradiated in LBE filled capsules. To separate the effect of exposure to LBE and neutron irradiation a parallel furnace experiment where the samples were exposed to LBE at the irradiation temperature for the corresponding time was conducted. Here we report results of the first extracted capsule which was irradiated about 6 months and dismantled after a cooling phase to decrease activity. The results of SSRT tests for irradiated T91 show that the exposure to LBE at 350 °C for a long time leads to the appearance of liquid metal embrittlement without any pre-treatment which is usually necessary to promote LME. Irradiation increases the effect of LME on the ductility of T91. In contrast to the findings for T91 the gained results also show that tensile tests on irradiated austenitic stainless steel 316L show no influence of LBE environment on the tensile properties.

  16. Laser deposited coatings of Co-Cr-Mo onto Ti-6Al-4V and SS316L substrates for biomedical applications.

    PubMed

    Wilson, J Michael; Jones, Nolan; Jin, Li; Shin, Yung C

    2013-10-01

    Functionally gradient bio-coating material was built by laser deposition. Co-Cr-Mo material was deposited on a Ti-6Al-4V substrate transitioning from 0% to 100%. Control over the cooling rate is shown to be a key to reduce the effects of thermal expansion differences of the materials. The microstructures and composition of the functionally gradient material (FGM) were characterized using an optical microscope, SEM, EDS, and XRD. EDS results showed a gradual transition to 50% Co-Cr-Mo and ∼100% Co-Cr-Mo on the top layer. XRD analysis showed the absence of a brittle intermetallic phase that forms between Titanium and Cobalt. As the amount of Co-Cr-Mo increased, the microhardness of the FGM samples significantly increased. A comparison was made between Co-Cr-Mo deposited on SS316L substrates as well as Ti-6Al-4V. The bonding strength of the coatings on both substrates was tested and found to meet the ASTM standard requirement.

  17. Effects of Ag and Cu ions on the microbial corrosion of 316L stainless steel in the presence of Desulfovibrio sp.

    PubMed

    Unsal, Tuba; Ilhan-Sungur, Esra; Arkan, Simge; Cansever, Nurhan

    2016-08-01

    The utilization of Ag and Cu ions to prevent both microbial corrosion and biofilm formation has recently increased. The emphasis of this study lies on the effects of Ag and Cu ions on the microbial corrosion of 316L stainless steel (SS) induced by Desulfovibrio sp. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to analyze the corrosion behavior. The biofilm formation, corrosion products and Ag and Cu ions on the surfaces were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and elemental mapping. Through circuit modeling, EIS results were used to interpret the physicoelectric interactions between the electrode, biofilm and culture interfaces. EIS results indicated that the metabolic activity of Desulfovibrio sp. accelerated the corrosion rate of SS in both conditions with and without ions. However, due to the retardation in the growth of Desulfovibrio sp. in the presence of Ag and Cu ions, significant decrease in corrosion rate was observed in the culture with the ions. In addition, SEM and EIS analyses revealed that the presence of the ions leads to the formation on the SS of a biofilm with different structure and morphology. Elemental analysis with EDS detected mainly sulfide- and phosphorous-based corrosion products on the surfaces.

  18. The effects of cold rolling orientation and water chemistry on stress corrosion cracking behavior of 316L stainless steel in simulated PWR water environments

    NASA Astrophysics Data System (ADS)

    Chen, Junjie; Lu, Zhanpeng; Xiao, Qian; Ru, Xiangkun; Han, Guangdong; Chen, Zhen; Zhou, Bangxin; Shoji, Tetsuo

    2016-04-01

    Stress corrosion cracking behaviors of one-directionally cold rolled 316L stainless steel specimens in T-L and L-T orientations were investigated in hydrogenated and deaerated PWR primary water environments at 310 °C. Transgranular cracking was observed during the in situ pre-cracking procedure and the crack growth rate was almost not affected by the specimen orientation. Locally intergranular stress corrosion cracks were found on the fracture surfaces of specimens in the hydrogenated PWR water. Extensive intergranular stress corrosion cracks were found on the fracture surfaces of specimens in deaerated PWR water. More extensive cracks were found in specimen T-L orientation with a higher crack growth rate than that in the specimen L-T orientation with a lower crack growth rate. Crack branching phenomenon found in specimen L-T orientation in deaerated PWR water was synergistically affected by the applied stress direction as well as the preferential oxidation path along the elongated grain boundaries, and the latter was dominant.

  19. Controlled electrophoretic deposition of HAp/β-TCP composite coatings on piranha treated 316L SS for enhanced mechanical and biological properties

    NASA Astrophysics Data System (ADS)

    Prem Ananth, K.; Nathanael, A. Joseph; Jose, Sujin P.; Oh, Tae Hwan; Mangalaraj, D.; Ballamurugan, A. M.

    2015-10-01

    Hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) bioactive materials have been used as individual coatings on steel implants employed in the fields of orthopedics and dentistry due to their excellent properties, which foster effective healing of the repair site. However, slow dissolution of HAp and fairly little fast dissolution of β-TCP present a major obstacle for such applications and this leads to the focus on the investigation of a mixture of HAp and β-TCP composite that forms biphasic calcium phosphate (BCP). The BCP coatings were achieved by thickness controlled electrophoretic deposition on piranha treated 316L SS. This method is well controlled and the anticipated dissolution rate could be attained with faster formation of new bone at the implant site, when compared to the individual HAp or β-TCP coating. The structural, functional, morphological and elemental composition of the coatings were characterized by using various analytical techniques. The BCP coating has been shown to have a role in obstructing the corrosion to a greater extent when in contact with SBF solution. The BCP coating also shows excellent in vitro and mechanical properties and osteoblasts cellular tests revealed that the coating was more effective in improving biocompatibility. This makes it an ideal candidate material for hard tissue replacement.

  20. A study of the neutron irradiation effects on the susceptibility to embrittlement of A316L and T91 steels in lead bismuth eutectic

    NASA Astrophysics Data System (ADS)

    Sapundjiev, D.; Al Mazouzi, A.; Van Dyck, S.

    2006-09-01

    The effects of neutron irradiation on the susceptibility to liquid metal embrittlement of two primary selected materials for MYRRHA project an accelerator driven system (ADS), was investigated by means of slow strain rate tests (SSRT). The latter were carried out at 200 °C in nitrogen and in liquid Pb-Bi at a strain rate of 5 × 10 -6 s -1. The small tensile specimens were irradiated at the BR-2 reactor in the MISTRAL irradiation rig at 200 °C for 3 reactor cycles to reach a dose of about 1.50 dpa. The SSR tests were carried out under poor and under dissolved oxygen conditions (˜1.5 × 10 -12 wt% dissolved oxygen) which at this temperature will favour formation of iron and chromium oxides. Although both materials differ in structure (fcc for A316L against bcc for T91), their flow behaviour in contact with liquid lead bismuth eutectic before and after irradiation is very similar. Under these testing conditions none of them was found susceptible to liquid metal embrittlement (LME).

  1. A Microstructural Study on the Observed Differences in Charpy Impact Behavior Between Hot Isostatically Pressed and Forged 304L and 316L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Cooper, Adam J.; Cooper, Norman I.; Bell, Andrew; Dhers, Jean; Sherry, Andrew H.

    2015-11-01

    With near-net shape technology becoming a more desirable route toward component manufacture due to its ability to reduce machining time and associated costs, it is important to demonstrate that components fabricated via Hot Isostatic Pressing (HIP) are able to perform to similar standards as those set by equivalent forged materials. This paper describes the results of a series of Charpy tests from HIP'd and forged 304L and 316L austenitic stainless steel, and assesses the differences in toughness values observed. The pre-test and post-test microstructures were examined to develop an understanding of the underlying reasons for the differences observed. The as-received microstructure of HIP'd material was found to contain micro-pores, which was not observed in the forged material. In tested specimens, martensite was detectable within close proximity to the fracture surface of Charpy specimens tested at 77 K (-196 °C), and not detected in locations remote from the fracture surface, nor was martensite observed in specimens tested at ambient temperatures. The results suggest that the observed changes in the Charpy toughness are most likely to arise due to differences in as-received microstructures of HIP'd vs forged stainless steel.

  2. Degradation of SS316L bipolar plates in simulated fuel cell environment: Corrosion rate, barrier film formation kinetics and contact resistance

    NASA Astrophysics Data System (ADS)

    Papadias, Dionissios D.; Ahluwalia, Rajesh K.; Thomson, Jeffery K.; Meyer, Harry M.; Brady, Michael P.; Wang, Heli; Turner, John A.; Mukundan, Rangachary; Borup, Rod

    2015-01-01

    A potentiostatic polarization method is used to evaluate the corrosion behavior of SS316L in simulated anode and cathode environments of polymer electrolyte fuel cells. A passive barrier oxide film is observed to form and reach steady state within ∼10 h of polarization, after which time the total ion release rates are low and nearly constant at ∼0.4 μg cm-2 h-1 for all potentials investigated. The equilibrium film thickness, however, is a function of the applied potential. The main ionic species dissolved in the liquid are predominately Fe followed by Ni, that account for >90% of the steady-state corrosion current. The dissolution rate of Cr is low but increases systematically at potentials higher than 0.8 V. The experimental ion release rates can be correlated with a point defect model using a single set of parameters over a broad range of potentials (0.2-1 V) on the cathode side. The interfacial contact resistance measured after 48 h of polarization is observed to increase with increase in applied potential and can be empirically correlated with applied load and oxide film thickness. The oxide film is substantially thicker at 1.5 V possibly because of alteration in film composition to Fe-rich as indicated by XPS data.

  3. Initial stage sintering model of 316L stainless steel with application to three dimensionally printed (3DP(TM)) components

    NASA Astrophysics Data System (ADS)

    Johnston, Scott R.

    supported by several sets of experimentation. Initial experimental results indicate that the anisotropic manufacturing of 3DP(TM) components result with orthotropic sintering strain development. Particle diameter experimentation revealed that components comprised of small particles (20mum) experienced more strain than components comprised of large particles (200mum). Strength experimentation showed two different types of mechanical responses from load-deflection measurements, where specimens with less sintering strain exhibited a brittle response and specimens with more sintering strain experienced plastic deformation.

  4. Influences of pH value, temperature, chloride ions and sulfide ions on the corrosion behaviors of 316L stainless steel in the simulated cathodic environment of proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Li, D. G.; Wang, J. D.; Chen, D. R.; Liang, P.

    2014-12-01

    316L stainless steel is in the passive state in a simulated cathodic environment, and the passivity of 316L SS is enhanced with increasing pH value, decreasing temperature, decreasing chloride ions and sulfide ions concentrations. Mott-Schottky plots show that the passive films appear a p-n heterojunction, and the donor and acceptor densities reach 1022 cm-3, showing a highly defective character of the passive film. The donor and acceptor densities increase with increasing temperature, increasing chloride ions and sulfide ions concentrations, while they decreased with increasing pH value. The decreased passivity and the increased doping density may be beneficial to the conductivity of the passive film, but they adversely affect the protectiveness of the passive film toward corrosion.

  5. Understanding the corrosion behavior of chromia-forming 316L stainless steel in dual oxidizing-reducing environment representative of SOFC interconnect

    SciTech Connect

    Ziomek-Moroz, Margaret; Cramer, Stephen D.; Holcomb, Gordon R.; Covino, Bernard S., Jr.; Matthes, Steven A.; Bullard, Sophie J.; Dunning, John S.; Alman, David E.; Singh, P.

    2003-11-01

    A and B site doped LaCrO3-based electronically conducting Perovskite ceramic materials have been extensively used as interconnects in solid oxide fule cells (SOFC) operating at 800° to 1000°C as the Perovskites offer good electrical conductivity, chemical compatibility with the adjacent components of the fuel cell, chemical stability in reducing and oxidizing atmospheres, and thermal expansion coefficients that match other cell components. However, requirements for good mechanical properties, electrical and thermal conductivities, and low cost make metallic interconnects more promising. Significant progress in reducing the operating temperature of SOFC from ~1000°C to ~750°C is expected to permit the use of metallic materials with substantial cost reduction. Among the commercially available metallic materials, Cr2O3 (chromia) scale-forming iron base alloys appear to be the most promising candidates since they can fulfill the technical and economical requirements. These alloys, however, remain prone to reactions with oxygen and water vapor at fuel cell operating conditions and formation of gaseous chromium oxides and oxyhydroxides. To study the degradation processes and corrosion mechanisms of commercial chromia scale-forming alloys under SOFC interconnect exposure conditions, 316L was selected for this research because of the availability of the materials. The dual environment to which the interconnect material was exposed consisted of dry air (simulates the cathode side environment) and a mixture of H2 and 3% H2O (simulates the anode side environment). Post-corrosion surface evaluation involved the use of optical and scanning electron microscopy, as well as energy dispersive X-ray analyses.

  6. A Comparative Evaluation of the Effect of Low Cycle Fatigue and Creep-Fatigue Interaction on Surface Morphology and Tensile Properties of 316L(N) Stainless Steel

    NASA Astrophysics Data System (ADS)

    Mariappan, K.; Shankar, Vani; Sandhya, R.; Bhaduri, A. K.; Laha, Kinkar

    2016-04-01

    In the present work, the deformation and damage evolution in 316L(N) stainless steel during low cycle fatigue (LCF) and creep-fatigue interaction (CFI) loadings have been compared by evaluating the residual tensile properties. Towards this, LCF and CFI experiments were carried out at constant strain amplitude of ±0.6 pct, strain rate of 3 × 10-3 s-1 and temperature of 873 K (600 °C). During CFI tests, 30 minutes hold period was introduced at peak tensile strain. Experiments were interrupted up to various levels of fatigue life viz. 5, 10, 30, 50, and 60 pct of the total fatigue life ( N f) under both LCF and CFI conditions. The specimens subjected to interrupted fatigue loadings were subsequently monotonically strained at the same strain rate and temperature up to fracture. Optical and scanning electron microscopy and profilometry were conducted on the untested and tested samples to elucidate the damage evolution during the fatigue cycling under both LCF and CFI conditions. The yield strength (YS) increased sharply with the progress of fatigue damage and attained saturation within 10 pct of N f under LCF condition. On the contrary, under CFI loading condition, the YS continuously increased up to 50 pct of N f, with a sharp increase of YS up to 5 pct of N f followed by a more gradual increase up to 50 pct of N f. The difference in the evolution of remnant tensile properties was correlated with the synergistic effects of the underlying deformation and damage processes such as cyclic hardening/softening, oxidation, and creep. The evolution of tensile properties with prior fatigue damage has been correlated with the change in surface roughness and other surface features estimated by surface replica technique and fractography.

  7. The Tribological Performance of Surface Treated Ti6A14V as Sliding Against Si3N4 Ball and 316L Stainless Steel Cylinder

    NASA Astrophysics Data System (ADS)

    Kao, W. H.; Su, Y. L.; Horng, J. H.; Huang, H. C.

    2016-10-01

    Closed field unbalanced magnetron sputtering was used to deposit diamond-like carbon (Ti-C:H) coatings on Ti6Al4V alloy and gas nitrided Ti6Al4V alloy. Four different specimens were prepared, namely untreated Ti6Al4V alloy (Ti6Al4V), gas nitrided Ti6Al4V alloy (N-Ti6Al4V), Ti-C:H-coated Ti6Al4V alloy (Ti-C:H/Ti6Al4V) and Ti-C:H-coated gas nitrided Ti6Al4V alloy (Ti-C:H/N-Ti6Al4V). The tribological properties of the four specimens were evaluated using a reciprocating wear tester sliding against a Si3N4 ball (point contact mode) and 316L stainless steel cylinder (line contact mode). The wear tests were performed in a 0.89 wt.% NaCl solution. The results showed that the nitriding treatment increased the surface roughness and hardness of the Ti6Al4V alloy and improved the wear resistance as a result. In addition, the Ti-C:H coating also improved the tribological performance of Ti6Al4V. For example, compared to the untreated Ti6Al4V sample, the Ti-C:H coating reduced the wear depth and friction coefficient by 340 times and 10 times, respectively, in the point contact wear mode, and 151 times and 9 times, respectively, in the line contact wear mode. It is thus inferred that diamond-like carbon coatings are of significant benefit in extending the service life of artificial biomedical implants.

  8. Effects of Mo content on microstructure and corrosion resistance of arc ion plated Ti-Mo-N films on 316L stainless steel as bipolar plates for polymer exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Kim, Kwang Ho; Shao, Zhigang; Wang, Feifei; Zhao, Shuang; Suo, Ni

    2014-05-01

    Bipolar plates are one of the most important components in PEMFC stack and have multiple functions, such as separators and current collectors, distributing reactions uniformly, and etc. Stainless steel is ideal candidate for bipolar plates owing to good thermal and electrical conductivity, good mechanical properties etc. However, stainless steel plate still cannot resist the corrosion of working condition. In this work, ternary Ti-Mo-N film was fabricated on 316L stainless steel (SS316L) as a surface modification layer to enhance the corrosion resistance. Effects of Mo content on the microstructure and corrosion resistance of Ti-Mo-N films are systematically investigated by altering sputtering current of the Mo target. XRD results reveal that the preferred orientation changes from [111] to [220] direction as Mo content in the film increases. The synthesized Ti-Mo-N films form a substitutional solid solution of (Ti, Mo)N where larger Mo atoms replace Ti in TiN crystal lattice. The TiN-coated SS316L sample shows the best corrosion resistance. While Mo content in the Ti-Mo-N films increases, the corrosion resistance gradually degrades. Compared with the uncoated samples, all the Ti-Mo-N film coated samples show enhanced corrosion resistance in simulated PEMFC working condition.

  9. Microstructural origins of radiation-induced changes in mechanical properties of 316 L and 304 L austenitic stainless steels irradiated with mixed spectra of high-energy protons and spallation neutrons

    NASA Astrophysics Data System (ADS)

    Sencer, B. H.; Bond, G. M.; Hamilton, M. L.; Garner, F. A.; Maloy, S. A.; Sommer, W. F.

    2001-07-01

    A number of candidate alloys were exposed to a particle flux and spectrum at Los Alamos Neutron Science Center (LANSCE) that closely match the mixed high-energy proton/neutron spectra expected in accelerator production of tritium (APT) window and blanket applications. Austenitic stainless steels 316 L and 304 L are two of these candidate alloys possessing attractive strength and corrosion resistance for APT applications. This paper describes the dose dependence of the irradiation-induced microstructural evolution of SS 316 L and 304 L in the temperature range 30-60°C and consequent changes in mechanical properties. It was observed that the microstructural evolution during irradiation was essentially identical in the two alloys, a behavior mirrored in their changes in mechanical properties. With one expection, it was possible to correlate all changes in mechanical properties with visible microstructural features. A late-term second abrupt decrease in uniform elongation was not associated with visible microstructure, but is postulated to be a consequence of large levels of retained hydrogen measured in the specimens. In spite of large amounts of both helium and hydrogen retained, approaching 1 at.% at the highest exposures, no visible cavities were formed, indicating that the gas atoms were either in solution or in subresolvable clusters.

  10. Electrochemical Study of AISI C1018 Steel in Methanesulfonic Acid Containing an Acetylenic Alcohol-Based Corrosion Inhibitor Formulation.

    PubMed

    Finšgar, Matjaž; Jackson, Jennifer

    2016-10-01

    In this work, the electrochemical potentiodynamic behavior of AISI C1018 lower-grade steel material was investigated in 20 wt.% methanesulfonic acid (MSA) solutions with or without different components to design corrosion inhibitor formulations based on acetylenic alcohol, cinnamaldehyde, 1-dodecylpyridinium chloride, and methanol. MSA has recently been considered as a new potential acid to be used in the matrix stimulation procedure and in well cleaning. It is demonstrated that AISI C1018 steel MSA needs to be inhibited. Inhibition type is determined for single components as well as for formulations.

  11. Hot hardness characteristics of ausformed AISI M-50, Matrix 2, WD-65, modified AISI 440-C, and Super Nitralloy

    NASA Technical Reports Server (NTRS)

    Chevalier, J. L.; Dietrich, M. W.; Zaretsky, E. V.

    1973-01-01

    Short-term hot hardness studies were performed with ausformed AISI M-50, Matrix 2, WD-65, modified AISI 440-C (14-4-1) and case hardened Super Nitralloy. Hardness levels of each material were measured at elevated temperatures in an electric furnace with a low oxygen environment. Test temperatures ranged from 294 to 877 K. The hot hardness characteristics of the ausformed AISI-M-50, Matrix 2 WD-65, and modified AISI 440-C were the same as those determined for high-speed tool steels. Hot hardness for these steels can be predicted within one point Rockwell C. The hot hardness characteristics of both the case and core of Super Nitralloy were superior to AISI 52100 but inferior to the high-speed tool steels. The short-term Rockwell C hardness at temperature for the Super Nitralloy material between 294 and 769 K can be predicted within one point Rockwell C hardness.

  12. Rolling-element fatigue life of AISI M-50 and 18-4-1 balls

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Zaretsky, E. V.

    1978-01-01

    Rolling element fatigue studies were conducted with AISI M-50, EFR 18-4-1, and VAR 18-4-1. Groups of 12.7 mm (1/2-in) diameter balls of each material were tested in the five ball fatigue tester. Test conditions included a load of 1540 N (347 lbf) giving a maximum Hertz stress of 5520 MPa (800 000 psi), a shaft speed of 10,700 rpm, and a contact angle of 30 deg. Tests were run at a race temperature of 339 K (150 F) with a type 2 ester lubricant. The rolling element fatigue life of AISI M-50 was not significantly different from that of EFR 18-4-1 or VAR 18-4-1 based on a statistical comparison of the test results.

  13. A Study on the Laser Spatter and the Oxidation Reactions During Selective Laser Melting of 316L Stainless Steel, Al-Si10-Mg, and Ti-6Al-4V

    NASA Astrophysics Data System (ADS)

    Simonelli, Marco; Tuck, Chris; Aboulkhair, Nesma T.; Maskery, Ian; Ashcroft, Ian; Wildman, Ricky D.; Hague, Richard

    2015-09-01

    The creation of an object by selective laser melting (SLM) occurs by melting contiguous areas of a powder bed according to a corresponding digital model. It is therefore clear that the success of this metal Additive Manufacturing (AM) technology relies on the comprehension of the events that take place during the melting and solidification of the powder bed. This study was designed to understand the generation of the laser spatter that is commonly observed during SLM and the potential effects that the spatter has on the processing of 316L stainless steel, Al-Si10-Mg, and Ti-6Al-4V. With the exception of Ti-6Al-4V, the characterization of the laser spatter revealed the presence of surface oxides enriched in the most volatile alloying elements of the materials. The study will discuss the implication of this finding on the material quality of the built parts.

  14. Surface fatigue life and failure characteristics of EX-53, CBS 1000M, and AISI 9310 gear materials

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.

    1985-01-01

    Spur gear endurance tests and rolling-element surface fatigue tests are conducted to investigate EX-53 and CBS 1000M steels for use as advanced application gear materials, to determine their endurance characteristics, and to compare the results with the standard AISI 9310 gear material. The gear pitch diameter is 8.89 cm (3.50 in). Gear test conditions are an oil inlet temperature of 320 K (116 F), an oil outlet temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. Bench-type rolling-element fatigue tests are conducted at ambient temperature with a bar specimen speed of 12,500 rpm and a maximum Hertz stress of 4.83 GPa (700 ksi). The EX-53 test gears have a surface fatigue life of twice that of the AISI 9310 spur gears. The CBS 1000M test gears have a surface fatigue life of more than twice that of the AISI 9310 spur gears. However, the CBS 1000M gears experience a 30-percent tooth fracture failure which limits its use as a gear material. The rolling-contact fatigue lines of RC bar specimens of EX-53 and ASISI 9310 are approximately equal. However, the CBS 1000M RC specimens have a surface fatigue life of about 50 percent that of the AISI 9310.

  15. Study on tempering behaviour of AISI 410 stainless steel

    SciTech Connect

    Chakraborty, Gopa; Das, C.R.; Albert, S.K.; Bhaduri, A.K.; Thomas Paul, V.; Panneerselvam, G.; Dasgupta, Arup

    2015-02-15

    Martensitic stainless steels find extensive applications due to their optimum combination of strength, hardness and wear-resistance in tempered condition. However, this class of steels is susceptible to embrittlement during tempering if it is carried out in a specific temperature range resulting in significant reduction in toughness. Embrittlement of as-normalised AISI 410 martensitic stainless steel, subjected to tempering treatment in the temperature range of 673–923 K was studied using Charpy impact tests followed by metallurgical investigations using field emission scanning electron and transmission electron microscopes. Carbides precipitated during tempering were extracted by electrochemical dissolution of the matrix and identified by X-ray diffraction. Studies indicated that temper embrittlement is highest when the steel is tempered at 823 K. Mostly iron rich carbides are present in the steel subjected to tempering at low temperatures of around 723 K, whereas chromium rich carbides (M{sub 23}C{sub 6}) dominate precipitation at high temperature tempering. The range 773–823 K is the transition temperature range for the precipitates, with both Fe{sub 2}C and M{sub 23}C{sub 6} types of carbides coexisting in the material. The nucleation of Fe{sub 2}C within the martensite lath, during low temperature tempering, has a definite role in the embrittlement of this steel. Embrittlement is not observed at high temperature tempering because of precipitation of M{sub 23}C{sub 6} carbides, instead of Fe{sub 2}C, preferentially along the lath and prior austenite boundaries. Segregation of S and P, which is widely reported as one of the causes for temper embrittlement, could not be detected in the material even through Auger electron spectroscopy studies. - Highlights: • Tempering behaviour of AISI 410 steel is studied within 673–923 K temperature range. • Temperature regime of maximum embrittlement is identified as 773–848 K. • Results show that type of

  16. Colloquium on Large Scale Improvement: Implications for AISI

    ERIC Educational Resources Information Center

    McEwen, Nelly, Ed.

    2008-01-01

    The Alberta Initiative for School Improvement (AISI) is a province-wide partnership program whose goal is to improve student learning and performance by fostering initiatives that reflect the unique needs and circumstances of each school authority. It is currently ending its third cycle and ninth year of implementation. "The Colloquium on Large…

  17. Recovery and recrystallization in AISI 321 steel under static conditions

    NASA Astrophysics Data System (ADS)

    Kratochvíl, P.; Smola, B.; Stulíková, I.; Vostrý, P.; Jandoš, F.; Šedivec, J.

    1985-03-01

    Static softening of AISI 321 steel after cold and hot deformation characterizing the industrial thermomechanical treatment was studied by means of tensile tests and TEM. The deformation temperature, the strain and the grain size were the main parameters determining the final softening. The results can be applied for optimization of the solution annealing.

  18. Effects of biofilm formation on the electrochemical behavior of AISI 304 SS in board machine environment

    SciTech Connect

    Carp, L.; Hakkarainen, T.; Raaska, L.

    1999-11-01

    The electrochemical behavior of and biofilm formation on AISI 304 stainless steel were studied in board machine environment with natural bacteria population. Open circuit potentials, redox-potential as well as different electrochemical measurements were performed. The biofilms formed were analyzed by microbial cultivation and by epifluorescence microscopy. The results of the measurements were compared with those performed both in sterilized white water and in artificial white water. The anodic polarization behavior of just immersed specimens was very similar in biotic (real), artificial and abiotic (sterilized) white water. Pitting initiated at very low potentials and continued to very negative values. The initiation of pitting became more difficult when the immersion time increased to 7 or 8 days in real, artificial or sterilized water. When the immersion time further increased, the pitting nucleated more easily in sterilized white water as well as in artificial white water than in biotic white water. In the laboratory equipment it was possible to maintain the biofilm already formed in the board mill, but the amount of sulfate reducing bacteria decreased and the amount of biofilm did not further increase. The composition and structure of the biofilm formed in laboratory differed from that formed in board mill conditions. The preliminary results indicate that the formation of biofilm in biotic white water rather inhibits than enhances the pitting corrosion of type AISI 304 stainless steel.

  19. Dense plasma focus-assisted nitriding of AISI-304

    NASA Astrophysics Data System (ADS)

    Shafiq, M.; Asghar, M.; Ahmad, S.; Sadiq, M.; Qayyum, A.; Zakaullah, M.

    Nitrogen ion implantation into AISI-304 stainless steel is carried out using a dense plasma focus device, operated at a charging voltage of 18 kV (discharge energyD1.45 kJ) with nitrogen filling at optimum pressure of 0.75 mbar. AISI-304 stainless steel samples placed axially above the anode tip are exposed to the ions for 10, 20 and 30 focus shots. X-ray diffraction (XRD), Vickers's micro hardness tester, scanning electron microscopy, and energy dispersive X-ray spectroscopy are used to explore the ion induced changes in the crystallographic structures, surface morphology, elemental composition and surface hardness of the ion irradiated samples. The XRD pattern confirms the formation of an expanded austenite phase, owing to nitrogen incorporated into the existing iron lattice. The results of micro hardness tester show that the hardness is increased about three times at an axial distance of 5 cm for 20 shots.

  20. Effect of five lubricants on life of AISI 9310 spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Zaretsky, E. V.

    1985-01-01

    Spur-gear surface fatigue tests were conducted with five lubricants using a single lot of consumable-electrode vacuum melted (CVM) AISI 9310 spur gears. The lot of gears was divided into five groups, each of which was tested with a different lubricant. The test lubricants are classified as either a synthetic hydrocarbon, mineral oil, or ester-based lubricant. All five lubricants have imilar viscosity and pressure-viscosity coefficients. A pentaerythritol base stock without sufficient antiwear additives produced a surface fatigue life pproximately 22 percent that of the same base stock with chlorine and phosphorus type additives. The presence of sulfur type antiwear additives in the lubricant did not appear to affect the surface fatigue life of the gears tested. No statistical difference in the 10-percent surface fatigue life was produced with four of the five lubricants.

  1. The aluminizing in powder technology of AISI 304 steel

    NASA Astrophysics Data System (ADS)

    Băitanu, D. B.; Găluşcă, D. G.; Achiţei, D. C.; Minciună, M. G.; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    The paper presents a study about the aluminizing treatments applied to AISI 304 stainless steel, with the purpose to improve the corrosion resistance. The aluminizing is realized in a powder medium, composed by aluminium powder (with 99.95% purity), aluminium oxide Al2O3 and ammonium chloride NH4Cl. The structural characterization was made by scanning electronic microscopy to highlight the structure of layer after aluminizing, at different magnitudes.

  2. Fragmentation of primary coarse macrostructure of AISI 321 steel

    NASA Astrophysics Data System (ADS)

    Jandoš, F.; Mazanec, K.; Kasl, J.; Kuneš, J.

    1988-04-01

    Fragmentation of primary grains in an ingot of AISI 321 steel was studied under common hammer forging conditions, i.e. at a temperature gradient existing in the cross-section of the ingot. It has been found that recrystallization in the surface zone starts by deformation induced migration of large subgrains observed inside primary grains, that static recrystallization takes place by intragranular twinning and that the fragmentation of the primary macrostructure is conditioned by static recrystallization.

  3. Comparisons of modified Vasco X-2 and AISI 9310 gear steels

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Zaretsky, E. V.

    1980-01-01

    Endurance tests were conducted with four groups of spur gears manufactured from three heats of consumable electrode vacuum melted (CVM) modified Vasco X-2. Endurance tests were also conducted with gears manufactured from CVM AISI 9310. Bench type rolling element fatigue tests were conducted with both materials. Hardness measurements were made to 811 K. There was no statistically significant life difference between the two materials. Life differences between the different heats of modified Vasco X-2 can be attributed to heat treat variation and resultant hardness. Carburization of gear flanks only can eliminate tooth fracture as a primary failure mode for modified Vasco X-2. However, a tooth surface fatigue spall can act as a nucleus of a tooth fracture failure for the modified Vasco X-2.

  4. Seawater piping systems designed with AISI 316 and RCP anodes

    SciTech Connect

    Valen, S.; Johnsen, R.; Gartland, P.O.; Drugli, J.M.

    1999-11-01

    Internal cathodic protection by resistor controlled anodes--Resistor controlled Cathodic Protection (RCP)--has been introduced as an alternative method for the prevention of localized corrosion of seawater transportation systems. More than 1000 RCP anodes have been installed in seawater piping systems made from highly alloyed stainless steel which previously had suffered from corrosion. The application of cheaper stainless steels like AISI 316 in combination with RCP anodes results in significant cost savings for the seawater system, and a few systems have been installed. This paper gives a short review of the theoretical background, and a presentation of the experience from some of the installations with these materials and RCP.

  5. Crack growth behavior of AISI-4340 steel during environmental exposure

    SciTech Connect

    Giannuzzi, L.A.

    1995-11-01

    AISI-4340 is observed to undergo stress corrosion cracking when subjected to a constant load during exposure to a 3.5% NaCl solution. Crack initiation, nucleation, and growth has been monitored as a function of time. Stepped regions consisting of fast and slow crack growth periods are shown to correspond to microstructural changes observed in the fracture surface of the steel. These regions of fast and slow crack rate variations with time show that the crack growth rates do not increase continuously with an increase in the stress intensity.

  6. Atomic diffusion in laser surface modified AISI H13 steel

    NASA Astrophysics Data System (ADS)

    Aqida, S. N.; Brabazon, D.; Naher, S.

    2013-07-01

    This paper presents a laser surface modification process of AISI H13 steel using 0.09 and 0.4 mm of laser spot sizes with an aim to increase surface hardness and investigate elements diffusion in laser modified surface. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, pulse repetition frequency (PRF), and overlap percentage. The hardness properties were tested at 981 mN force. Metallographic study and energy dispersive X-ray spectroscopy (EDXS) were performed to observe presence of elements and their distribution in the sample surface. Maximum hardness achieved in the modified surface was 1017 HV0.1. Change of elements composition in the modified layer region was detected in the laser modified samples. Diffusion possibly occurred for C, Cr, Cu, Ni, and S elements. The potential found for increase in surface hardness represents an important method to sustain tooling life. The EDXS findings signify understanding of processing parameters effect on the modified surface composition.

  7. Effect of tip relief on endurance characteristics of super nitralloy and AISI M-50 spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Zaretsky, E. V.

    1974-01-01

    Tests were conducted with two groups of 8.89-centimeter (3.5-in.) pitch diameter spur gears with standard 20 deg involute profile with tip relief made of CVM Super-Nitralloy (5Ni-2Al) and CVM AISI M-50 at a temperature of 350 K (170 F). Super-Nitralloy gears with tip relief had a life 150 percent that of gears without tip relief. An increased scoring phenomenon was noted with the Super-Nitralloy gears with tip relief. Through-hardened AISI M-50 gears with tip relief failed due to tooth fracture. AISI M-50 gears without tip relief had a life approximately 40 times greater than the AISI M-50 gears with tip relief.

  8. Fretting of AISI 9310 and selected fretting resistant surface treatments

    NASA Technical Reports Server (NTRS)

    Bill, R. C.

    1977-01-01

    Fretting wear experiments were conducted with uncoated AISI 9310 mating surfaces, and with combinations incorporating a selected coating to one of the mating surfaces. Wear measurements and SEM observations indicated that surface fatigue, as made evident by spallation and surface crack formation, is an important mechanism in promoting fretting wear to uncoated 9310. Increasing humidity resulted in accelerated fretting, and a very noticeable difference in nature of the fretting debris. Of the coatings evaluated, aluminum bronze with a polyester additive was most effective at reducing wear and minimizing fretting damage to the mating uncoated surface, by means of a selflubricating film that developed on the fretting surfaces. Chromium plate performed as an effective protective coating, itself resisting fretting and not accelerating damage to the uncoated surface.

  9. Simulation of Thermo-viscoplastic Behaviors for AISI 4140 Steel

    NASA Astrophysics Data System (ADS)

    Li, Hong-Bin; Feng, Yun-Li

    2016-04-01

    The thermo-viscoplastic behaviors of AISI 4140 steel are investigated over wide ranges of strain rate and deformation temperature by isothermal compression tests. Based on the experimental results, a unified viscoplastic constitutive model is proposed to describe the hot compressive deformation behaviors of the studied steel. In order to reasonably evaluate the work hardening behaviors, a strain hardening material constant (h0) is expressed as a function of deformation temperature and strain rate in the proposed constitutive model. Also, the sensitivity of initial value of internal variable s to the deformation temperature is discussed. Furthermore, it is found that the initial value of internal variable s can be expressed as a linear function of deformation temperature. Comparisons between the measured and predicted results confirm that the proposed constitutive model can give an accurate and precise estimate of the inelastic stress-strain relationships for the studied high-strength steel.

  10. Stress Ratio Effect on Ratcheting Behavior of AISI 4340 Steel

    NASA Astrophysics Data System (ADS)

    Divya Bharathi, K.; Dutta, K.

    2016-02-01

    Ratcheting is known as accumulation of plastic strain during asymmetric cyclic loading of metallic materials under non-zero mean stress. This phenomenon reduces fatigue life of engineering materials and thus limits the life prediction capacity of Coffin-Manson relationship. This study intends to investigate the ratcheting behavior in AISI 4340 steel which is mainly used for designing of railway wheel sets, axles, shafts, aircraft components and other machinery parts. The effect of stress ratio on the ratcheting behaviour in both annealed and normalised conditions were investigated for investigated steel. Ratcheting tests were done at different stress ratios of -0.4, -0.6 and -0.8. The results showed that the material responds to hardening behavior and nature of strain accumulation is dependent on the magnitude of stress ratio. The post ratcheted samples showed increase in tensile strength and hardness which increases with increasing stress ratio and these variations in tensile properties are correlated with the induced cyclic hardening.

  11. Texture evolution in thin-sheets on AISI 301 metastable stainless steel under dynamic loading

    SciTech Connect

    Kim, K.Y.; Kozaczek, K.; Kulkarni, S.M.; Bastias, P.C.; Hahn, G.T.

    1995-05-08

    The evolution of texture in thin sheets of metastable austenitic stainless steel AISI 301 is affected by external conditions such as loading rate and temperature, by inhomogeneous deformation phenomena such as twinning and shear band formation, and by the concurent strain induced phase transformation of the retained austenitc ({gamma}) into martensite ({alpha}). The present paper describes texture measurements on different gauges of AISI 301 prior and after uniaxial stretching under different conditions.

  12. Investment cast AISI H13 tooling for automotive applications

    SciTech Connect

    Maguire, M.C.; Baldwin, M.D.; Hochanadel, P.W.; Edwards, G.R.

    1995-07-01

    While many techniques exist for production of soft tooling, for die casting there is limited recent experience with cast tooling. The most common US alloy used for manufacture of die casting tooling is wrought AISI H13. If the performance of the cast material is comparable to the wrought counterpart, the use of investment cast HI 3 tooling directly from patterns made via rapid prototyping is of considerable interest. A metallurgical study of investment cast H13 was conducted to evaluate the mechanical behavior in simulated die casting applications. Variable thickness plate investment castings of AISI H13 hot work die steel were produced and characterized in the as-cast and heat-treated conditions. The characterization included light microscopy and mechanical testing. Wrought samples of standard and premium grade H13 were heat-treated and characterized similarly for comparison. Microstructural differences were observed in as-cast samples produced in different section thicknesses. Dendrite cell size and carbide morphology constituted the most prominent microstructural differences observed. After a full heat-treatment, microstructural differences between the wrought material and cast materials were slight regardless of section thickness.The mechanical properties of the cast and heat-treated material proved similar to the properties of the standard heat-treated wrought material. A thermal fatigue testing unit was to con-elate the heat checking susceptibility of H13 steel to its processing and consequent microstructural condition. Surface hardness decreased significantly with thermal cycling, and heat checking was observed in as few as 50 cycles. Thermal softening and thermal fatigue susceptibility were quantified and discussed relative to the microstructural conditions created by processing and heat-treatment. It was found that the premium grade wrought H13 steel provided the best overall resistance to heat checking.

  13. A Life Study of Ausforged, Standard Forged and Standard Machined AISI M-50 Spur Gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Bamberger, E. N.; Zaretsky, E. V.

    1975-01-01

    Tests were conducted at 350 K (170 F) with three groups of 8.9 cm (3.5 in.) pitch diameter spur gears made of vacuum induction melted (VIM) consumable-electrode vacuum-arc melted (VAR), AISI M-50 steel and one group of vacuum-arc remelted (VAR) AISI 9310 steel. The pitting fatigue life of the standard forged and ausforged gears was approximately five times that of the VAR AISI 9310 gears and ten times that of the bending fatigue life of the standard machined VIM-VAR AISI M-50 gears run under identical conditions. There was a slight decrease in the 10-percent life of the ausforged gears from that for the standard forged gears, but the difference is not statistically significant. The standard machined gears failed primarily by gear tooth fracture while the forged and ausforged VIM-VAR AISI M-50 and the VAR AISI 9310 gears failed primarily by surface pitting fatigue. The ausforged gears had a slightly greater tendency to fail by tooth fracture than the standard forged gears.

  14. Phase Transformations During the Low-Temperature Nitriding of AISI 2205 Duplex Stainless Steel

    NASA Astrophysics Data System (ADS)

    Yan, Jing; Gu, Tan; Qiu, Shaoyu; Wang, Jun; Xiong, Ji; Fan, Hongyuan

    2015-02-01

    Liquid nitriding of type AISI 2205 duplex stainless steel was conducted at 723 K (450 °C), using one type of novel low-temperature liquid chemical thermo-treatment. The transformation of the nitrided surface microstructure was systematically studied. Experimental results revealed that a nitrided layer formed on the sample surface with the thickness ranging from 3 to 28 μm, depending on nitriding time. After the 2205 duplex stainless steel was subjected to liquid nitriding 723 K (450 °C) for less than 8 hours, the pre-existing ferrite region on the surface transformed into the expanded austenite (S phase) by the infusion of nitrogen atoms, most of which stay in the interstitial sites. Generally, the dominant phase of the nitrided layer was the expanded austenite. When the nitriding time prolonged up to 16 hours, some pre-existing ferrite in expanded austenite was decomposed and ɛ-nitride precipitated subsequently. When the treatment time went up to 40 hours, large amount of ɛ-nitride and CrN precipitates were observed in the pre-existing ferritic region in the expanded austenite. Furthermore, many nitrides precipitated from the pre-austenite region. Acicular nitride was identified by transmission electron microscopy. The thickness of the nitrided layer increased with increasing nitriding time. The growth of the nitrided layer is mainly due to nitrogen diffusion in accordance with the expected parabolic rate law. Liquid nitriding effectively increased the surface hardness of 2205 duplex stainless steel by a factor of 3.

  15. MR Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types.

    PubMed

    Burg, Matthias C; Bunck, Alexander C; Seifarth, Harald; Buerke, Boris; Kugel, Harald; Hesselmann, Volker; Köhler, Michael; Heindel, Walter; Maintz, David

    2011-01-01

    Purpose. To evaluate stent lumen visibility of a large sample of different peripheral arterial (iliac, renal, carotid) stents using magnetic resonance angiography in vitro. Materials and Methods. 21 different stents and one stentgraft (10 nitinol, 7 316L, 2 tantalum, 1 cobalt superalloy, 1 PET + cobalt superalloy, and 1 platinum alloy) were examined in a vessel phantom (vessel diameters ranging from 5 to 13 mm) filled with a solution of Gd-DTPA. Stents were imaged at 1.5 Tesla using a T1-weighted 3D spoiled gradient-echo sequence. Image analysis was performed measuring three categories: Signal intensity in the stent lumen, lumen visibility of the stented lumen, and homogeneity of the stented lumen. The results were classified using a 3-point scale (good, intermediate, and poor results). Results. 7 stents showed good MR lumen visibility (4x nitinol, 2x tantalum, and 1x cobalt superalloy). 9 stents showed intermediate results (5x nitinol, 2x 316L, 1x PET + cobalt superalloy, and 1x platinum alloy) and 6 stents showed poor results (1x nitinol, and 5x 316L). Conclusion. Stent lumen visibility varies depending on the stent material and type. Some products show good lumen visibility which may allow the detection of stenoses inside the lumen, while other products cause artifacts which prevent reliable evaluation of the stent lumen with this technique. PMID:22091380

  16. MR Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types

    PubMed Central

    Burg, Matthias C.; Bunck, Alexander C.; Seifarth, Harald; Buerke, Boris; Kugel, Harald; Hesselmann, Volker; Köhler, Michael; Heindel, Walter; Maintz, David

    2011-01-01

    Purpose. To evaluate stent lumen visibility of a large sample of different peripheral arterial (iliac, renal, carotid) stents using magnetic resonance angiography in vitro. Materials and Methods. 21 different stents and one stentgraft (10 nitinol, 7 316L, 2 tantalum, 1 cobalt superalloy, 1 PET + cobalt superalloy, and 1 platinum alloy) were examined in a vessel phantom (vessel diameters ranging from 5 to 13 mm) filled with a solution of Gd-DTPA. Stents were imaged at 1.5 Tesla using a T1-weighted 3D spoiled gradient-echo sequence. Image analysis was performed measuring three categories: Signal intensity in the stent lumen, lumen visibility of the stented lumen, and homogeneity of the stented lumen. The results were classified using a 3-point scale (good, intermediate, and poor results). Results. 7 stents showed good MR lumen visibility (4x nitinol, 2x tantalum, and 1x cobalt superalloy). 9 stents showed intermediate results (5x nitinol, 2x 316L, 1x PET + cobalt superalloy, and 1x platinum alloy) and 6 stents showed poor results (1x nitinol, and 5x 316L). Conclusion. Stent lumen visibility varies depending on the stent material and type. Some products show good lumen visibility which may allow the detection of stenoses inside the lumen, while other products cause artifacts which prevent reliable evaluation of the stent lumen with this technique. PMID:22091380

  17. An Electrochemical Processing Strategy for Improving Tribological Performance of Aisi 316 Stainless Steel Under Grease Lubrication

    NASA Astrophysics Data System (ADS)

    Zou, Jiaojuan; Li, Maolin; Lin, Naiming; Zhang, Xiangyu; Qin, Lin; Tang, Bin

    2014-12-01

    In order to improve the tribological performance of AISI 316 stainless steel (316 SS) under grease lubrication, electrochemical processing was conducted on it to obtain a rough (surface texturing-like) surface by making use of the high sensitivity of austenitic stainless steel to pitting corrosion in Cl--rich environment. Numerous corrosion pits or micro-ditches acted as micro-reservoirs on the obtained surface. While the grease could offer consistent lubrication, and then improve the tribological performance of 316 SS. Tribological behaviors of raw 316 SS and the treated sample were measured using a reciprocating type tribometer sliding against GCr15 steel counterpart under dry and grease lubrication conditions. The results showed that the mass losses of the two samples were in the same order of magnitude, and the raw sample exhibited lower friction coefficient in dry sliding. When the tests were conducted under grease lubrication condition, the friction coefficients and mass losses of the treated sample were far lower than those of the raw 316 SS. The tribological performance of 316 SS under grease lubrication was drastically improved after electrochemical processing.

  18. Deposition of titanium nitride on AISI-304 in a plasma focus environment

    NASA Astrophysics Data System (ADS)

    Zeb, S.; Qayyum, A.; Shafiq, M.; Zakaullah, M.

    2008-05-01

    Polycrystalline, smooth, and hard thin films of TiN are successfully deposited on AISI-304 substrates using a 1.5kJ Mather-type dense plasma focus device charged at 18kV. The purpose of this study is to investigate the structural and mechanical properties of the TiN thin films in terms of ion dose and substrate position to establish the optimum deposition conditions. The films are analyzed using XRD, SEM, electron microprobe and micro-hardness testing. XRD confirms the deposition of a polycrystalline TiN thin film together with the emergence of an iron chromium nickel phase. The surface hardness-in comparison to the unexposed substrate-is found to increase up to 250% when a film is deposited using 30 focus shots at an axial distance of 6cm. SEM micrographs show that the quality of the film is improved with an increasing number of focus shots. The constituent elements of the film are also confirmed by electron microprobe.

  19. The Surface Fatigue Life of Contour Induction Hardened AISI 1552 Gears

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Turza, Alan; Chaplin, Mike

    1995-01-01

    Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened, and ground to a 0.4 micron (16 micro-in.) rms surface finish. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a bulk gear temperature of approximately 350 K (170 F) and a speed of 10,000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The test results showed that the 10 percent surface fatigue (pitting) life of the contour hardened AISI 1552 test gears was 1.7 times that of the carburized and hardened AISI 9310 test gears. Also there were two early failures of the AISI 1552 gears by bending fatigue.

  20. Ferromagnetic properties of cold rolled AISI 304L steel

    NASA Astrophysics Data System (ADS)

    Tavares, S. S. M.; da Silva, M. R.; Neto, J. M.; Miraglia, S.; Fruchart, D.

    2002-04-01

    The ferromagnetic properties (coercive force, residual and saturation magnetisation) of a cold rolled AISI 304L stainless steel were measured as function of the applied deformation, using a vibrating sample magnetometer. The martensite volume fraction produced by deformation was calculated through the magnetisation saturation ( σs) value. A maximum amount of martensite (81%) was obtained by applying a true deformation ɛ=2.41 and a heat treatment at 400°C after rolling. The residual induction ( Br) and the squareness (=ratio between residual ( Br) and saturation ( Bs) inductions) increased, while the coercive field ( Hc) decreased with the amount of deformation. The heat treatment at 400°C promotes as well the increase of both Br and Br/ Bs and the decrease of Hc. The magnetic properties obtained in the most severely deformed samples ( Hc=23.08-23.63 kJ/m 3, Br=1.01-1.20 T and Bs=1.12-1.28 T) are comparable to that of some hard and semi-hard alloys used as magnets. The stability of the ferromagnetic martensite ( α') was investigated by thermomagnetic analysis. The starting ( As) and final ( Af) temperatures of the martensite phase ( α') transformation into austenite during heating were determined to As=430-440°C and Af=610-616°C.

  1. Investigations on the Predictability of Coining Stainless Steel AISI 410

    NASA Astrophysics Data System (ADS)

    Grobbink, S. J.; Klaseboer, G.; Post, J.; Huetink, J.

    2010-06-01

    Due to the increasing trend towards miniaturization, various industries demand the knowledge of materials forming on microscale. Forming has many advantages above machining such as high accuracy, low costs and strengthening by cold-working. However, a drawback of microforming is that it leads to problems caused by so-called size effects. A lot of research has been done on this topic, but only a minor part deals with the forming of high strength materials. In this study two channels with 0.25 mm width and 4.5 mm length are formed in stainless steel sheet AISI 410 with an initial sheet thickness 0.5 mm. The channels are formed by the coining process. The experiments have been repeated in which all dimensions are scaled down by a factor two, in order to check if size effects occur. Ring compression tests are used to determine a shear friction coefficient. A finite element model was build up and solved with MSC.Marc in order to gain a better understanding of the coining process. A size dependent material model known from literature and a conventional material model is used for the simulations. Both results are compared with the experimental results.

  2. The Forming of AISI 409 sheets for fan blade manufacturing

    SciTech Connect

    Foroni, F. D.; Menezes, M. A.; Moreira Filho, L. A.

    2007-04-07

    The necessity of adapting the standardized fan models to conditions of higher temperature has emerged due to the growth of concern referring to the consequences of the gas expelling after the Mont Blanc tunnel accident in Italy and France, where even though, with 100 fans in operation, 41 people died. The objective of this work is to present an alternative to the market standard fans considering a new technology in constructing blades. This new technology introduces the use of the stainless steel AISI 409 due to its good to temperatures of gas exhaust from tunnels in fire situation. The innovation is centered in the process of a deep drawing of metallic sheets in order to keep the ideal aerodynamic superficies for the fan ideal performance. Through the impression of circles on the sheet plane it is shown, experimentally, that, during the pressing process, the more deformed regions on the sheet plane of the blade can not reach the deformation limits of the utilized sheet material.

  3. Modeling the Flow Curve of AISI 410 Martensitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Momeni, A.; Dehghani, K.; Heidari, M.; Vaseghi, M.

    2012-11-01

    In the present study, hot deformation behavior of AISI 410 martensitic stainless steel was investigated and modeled after conducting compression tests at the temperature range of 900-1150 °C and strain rate range of 0.001-1 s-1. At the studied temperature and strain rates, the flow curves were typical of dynamic recrystallization (DRX) showing a hardening peak followed by a softening one, and a steady state. The flow curves up to the peaks were modeled using the Estrin and Mecking equation. The softening due to DRX was also considered to increase the consistency of the developed model. The experimental equation proposed by Cingara and McQueen was also used to model the work hardening region. The results showed that the phenomenological model based on the Estrin and Mecking equation resulted in a better model for the work hardening region. Based on the Avrami equation, a model was developed to estimate the flow softening due to DRX between the peak and the starting point of steady state. The average value of the Avrami exponent was determined as 2.2, and it decreased with the increasing Zener-Hollomon parameter.

  4. High-temperature oxidation behavior of aluminized AISI 4130 steel

    NASA Astrophysics Data System (ADS)

    Badaruddin, Mohammad; Wang, Chaur Jeng; Wardono, Herry; Tarkono, Asmi, Dwi

    2016-02-01

    AISI 4130 steel was dipped into a molten aluminum bath at 700°C for 16 s to produce an aluminide coating on the steel substrate. The coating, which consisted of an Al-rich layer and an FeAl3 and Fe2Al5 intermetallic layer, strongly adhered to the steel substrate. High-temperature oxidation of the bare steel and aluminized steel was performed by thermogravimetry at 850°C for 49 h in static air. The oxidation products were characterized by scanning electron microscopy and energy-dispersive spectroscopy. The aluminide coating could increase the oxidation resistance of the bare steel by a factor of ˜19. The increase in high-temperature oxidation resistance of the aluminized steel is attributed to the formation of protective alumina scale (α-Al2O3). Although iron oxide nodules grew on the aluminide coating surface, the oxidation rate of the aluminide coatings was very low. After 49 h of oxidation, agglomerates of α-Al2O3 fine grains grew on the rod-shaped FeAl phases.

  5. Abnormal grain growth in AISI 304L stainless steel

    SciTech Connect

    Shirdel, M.; Mirzadeh, H.; Parsa, M.H.

    2014-11-15

    The microstructural evolution during abnormal grain growth (secondary recrystallization) in 304L stainless steel was studied in a wide range of annealing temperatures and times. At relatively low temperatures, the grain growth mode was identified as normal. However, at homologous temperatures between 0.65 (850 °C) and 0.7 (900 °C), the observed transition in grain growth mode from normal to abnormal, which was also evident from the bimodality in grain size distribution histograms, was detected to be caused by the dissolution/coarsening of carbides. The microstructural features such as dispersed carbides were characterized by optical metallography, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, and microhardness. Continued annealing to a long time led to the completion of secondary recrystallization and the subsequent reappearance of normal growth mode. Another instance of abnormal grain growth was observed at homologous temperatures higher than 0.8, which may be attributed to the grain boundary faceting/defaceting phenomenon. It was also found that when the size of abnormal grains reached a critical value, their size will not change too much and the grain growth behavior becomes practically stagnant. - Highlights: • Abnormal grain growth (secondary recrystallization) in AISI 304L stainless steel • Exaggerated grain growth due to dissolution/coarsening of carbides • The enrichment of carbide particles by titanium • Abnormal grain growth due to grain boundary faceting at very high temperatures • The stagnancy of abnormal grain growth by annealing beyond a critical time.

  6. AISI waste oxide recycling program. Final technical report

    SciTech Connect

    Aukrust, E.; Downing, K.B.; Sarma, B.

    1995-08-01

    In March 1995 AISI completed a five-year, $60 million collaborative development program on Direct Steelmaking cost-shared by DOE under the Metals Initiative. This program defined an energy-efficient and environmentally-friendly technology to produce hot metal for steelmaking directly from coal and iron ore pellets without incurring the high capital costs and environmental problems associated with traditional coke oven and blast furnace technology. As it becomes necessary to replace present capacity, this new technology will be favored because of reduced capital costs, higher energy efficiency, and lower operating costs. In April 1994, having failed to move forward with a demonstration plant for direct ironmaking, despite substantial efforts by both Stelco and Geneva Steel, an alternative opportunity was sought to commercialize this new technology without waiting until existing ironmaking capacity needed to be replaced. Recycling and resource recovery of steel plant waste oxides was considered an attractive possibility. This led to approval of a ten-month, $8.3 million joint program with DOE on recycling steel plant waste oxides utilizing this new smelting technology. This highly successful trial program was completed in December 1994. The results of the pilot plant work and a feasibility study for a recycling demonstration plant are presented in this final technical report.

  7. Hot compression deformation behavior of AISI 321 austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Haj, Mehdi; Mansouri, Hojjatollah; Vafaei, Reza; Ebrahimi, Golam Reza; Kanani, Ali

    2013-06-01

    The hot compression behavior of AISI 321 austenitic stainless steel was studied at the temperatures of 950-1100°C and the strain rates of 0.01-1 s-1 using a Baehr DIL-805 deformation dilatometer. The hot deformation equations and the relationship between hot deformation parameters were obtained. It is found that strain rate and deformation temperature significantly influence the flow stress behavior of the steel. The work hardening rate and the peak value of flow stress increase with the decrease of deformation temperature and the increase of strain rate. In addition, the activation energy of deformation ( Q) is calculated as 433.343 kJ/mol. The microstructural evolution during deformation indicates that, at the temperature of 950°C and the strain rate of 0.01 s-1, small circle-like precipitates form along grain boundaries; but at the temperatures above 950°C, the dissolution of such precipitates occurs. Energy-dispersive X-ray analyses indicate that the precipitates are complex carbides of Cr, Fe, Mn, Ni, and Ti.

  8. Surface fatigue life of CBN and vitreous ground carburized and hardened AISI 9310 spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Patel, P. R.

    1988-01-01

    Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9310 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temeprature of 320 K (116 F), an outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.

  9. Corrosion resistance of the AISI 304, 316 and 321 stainless steel surfaces modified by laser

    NASA Astrophysics Data System (ADS)

    Szubzda, B.; Antończak, A.; Kozioł, P.; Łazarek, Ł.; Stępak, B.; Łęcka, K.; Szmaja, A.; Ozimek, M.

    2016-02-01

    The article presents the analysis results of the influence of laser fluence on physical and chemical structure and corrosion resistance of stainless steel surfaces modified by irradiating with nanosecond-pulsed laser. The study was carried out for AISI 304, AISI 316 and AISI 321 substrates using Yb:glass fiber laser. All measurements were made for samples irradiated in a broad range of accumulated fluence (10÷400 J/cm2). The electrochemical composition (by EDX) and surface morphology (by SEM) of the prepared surfaces were carried out. Finally, corrosion resistance was analyzed by a potentiodynamic electrochemical test. The obtained results showed very high corrosion resistance for samples made by fluency of values lower than 100 J/cm2. In this case, higher values of corrosion potentials and breakdown potentials were observed. A correlation between corrosion phenomena, the range of laser power (fluence) and the results of chemical and structural tests were also found.

  10. Characterization of Structural Conditions of AISI 316 Analog Stainless Steel Irradiated in the BN-350 Reactor

    SciTech Connect

    Maksimkin, O. P.; Tsai, K V.; Turubarova, L. G.; Doronina, T. A.; Garner, Francis A.

    2004-08-24

    In several recently published studies conducted on a Soviet analog of AISI 321 stainless steel irradiated in either fast reactors or light water reactors, it was shown that the void swelling phenomenon extended to temperatures as low as {approx} 300 C, when produced by neutron irradiation at dpa rates in the range 10(-7 power) to 10(-8 power) dpa/sec. Other studies yielded similar results for AISI 316. In the current study a blanket duct assembly from BN-350, constructed from the Soviet analog of AISI 316, also exhibits swelling at dpa rates on the order of 10(-8 power) dpa/sec, with voids seen as low as 281 C and only 1.3 dpa. It appears that low-temperature swelling at low dpa rates occurs in 300 series stainless steels in general, and during irradiations conducted in either fast or mixed spectrum reactors.

  11. Multilayer Roll-Bonded Sandwich: Processing, Mechanical Performance, and Bioactive Behavior

    SciTech Connect

    Palkowski H.; Stanic V.; Carrado, A.

    2012-03-30

    Multifunctionality and improving the properties of materials make it necessary to use hybrid systems such as combinations of metals with polymers. Their applications can be found in all areas where light weight and improved and adapted mechanical properties as well as high functionality are needed. Moreover, tailored types of hybrids can be interesting for biomedical applications, as under specific conditions they show, e.g., good strength combined with high elasticity. Herein, we present preliminary tests on the biomimetic behavior of AISI SS316L/polypropylene copolymer/AISI SS316L sandwich. Biomimetic coatings were produced by inducing a calcium phosphate layer in a way similar to the process of natural bone formation. Knowledge of the formability of three-layered sandwich sheets and their biomimetic behavior is presented.

  12. Coupled Multi-Electrode Investigation of Crevice Corrosion of AISI 316 Stainless Steel

    SciTech Connect

    F. Bocher; F. Presuel-Moreno; N.D. Budinasky; J.R. Scully

    2006-06-23

    Close packed coupled multi-electrodes arrays (MEA) simulating a planar electrode were used to measure the current evolution as a function of position during initiation and propagation of crevice corrosion of AISI 316 stainless steel. Scaling laws derived from polarization data enabled the use of rescaled crevices providing spatial resolution. Crevice corrosion of AISI 316 stainless steel in 0.6 M NaCl at 50 C was found to initiate close to the crevice mouth and to spread inwards with time. The local crevice current density increased dramatically over a short period to reach a limiting value.

  13. Local Reversion of Cold Formed AISI 301LN

    NASA Astrophysics Data System (ADS)

    Järvenpää, A.; Jaskari, M.; Hietala, M.; Mäntyjärvi, K.

    This study demonstrates applying laser heat treatment for reversion treatments of cold-formed AISI 301LN. Sheets were cold- rolled to final thicknesses of 1.5 and 3 mm (65pct reduction), having martensite fraction of 70-95%. Sheets were heated locally by a laser beam to various peak temperatures to obtain different degrees of martensite reversion to austenite. Mechanical properties and formability of grain-refined and coarse-grained structures were measured by tensile, bending and Erichsen cup tests. In addition to standard Erichsen cup test, additional interrupted tests were carried out, where cups were first stretched close to the critical strain. Drawn cups were then heated locally by a laser beam to revitalize the structure and thereby enhance the formability in the following cupping test until failure. Various structures were produced: completely reverted microstructures (T > 700 °C) with grain sizes 0.9 - 2 μm in addition to partially reverted structure (T < 700 °C) containing nano- and ultrafine-grained austenite (0.6 μm) with some martensite. Results showed that local laser heat treatment is suitable for the reversion treatment to refine the austenite grain size. Refinement of the austenitic structures increased strength properties and the formability was better than with coarse grained structures having the same strength. Especially the yield strength was significantly enhanced, being around 900 MPa in the strongest reverted structure compared to the 300-400 MPa of the coarse grained austenitic structure. It was demonstrated that the local laser treatment restored formability of the drawn cups, allowing stretching to be continued.

  14. Welding procedure specification: gas tungsten arc welding of AISI 41XX steels

    SciTech Connect

    Wodtke, C.H.; Frizzell, D.R.

    1985-08-01

    Procedure WPS-126 is qualified under Section IX of the ASME Boiler and Pressure Vessel Code for gas tungsten arc welding of AISI 4130 and 4142 steel (ASTM A519) (P-No: None), 0.438-in. wall pipe; filler metal is AMS 6457, Class 4130 MC (F-, A-No: None).

  15. Eddy Current Assessment of the Cold Rolled Deformation Behavior of AISI 321 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Liu, Kunpeng; Zhao, Zihua; Zhang, Zheng

    2012-08-01

    Applicability of the eddy current (EC) technique in assessing martensite phase transformation during cold reduction in AISI 321 stainless steel was investigated. An empirical model based on measured EC parameters was developed for predicting the volume fraction of strain-induced martensite. Good agreement was found between the model-predicted and the experimental data.

  16. A life study of AISI M-50 and Super Nitralloy spur gears with and without tip relief

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Zaretsky, E. V.

    1973-01-01

    Tests were conducted at 170 F with groups of 3.5-in.-pitch-diameter spur gear with and without tip relief made of consumable-electrode vacuum melted (CVM) Spur Nitralloy (5Ni-2Al) and CVM AISI M-50 steel. The AISI M-50 gears without tip relief had lives approximately 50 percent longer than the Super Nitralloy gears without tip relief. However, the Super Nitralloy gears with tip relief had lives equal to the AISI M-50 gears without tip relief. The difference in lives were not statistically significant. All gears failed by classical pitting fatigue at the pitch circle. However, the AIAI M-50 gears with tip relief failed by tooth fracture. AISI M-50 gear sets without tip relief having a spalled gear tooth which were deliberately overrun after spalling had occurred, failed by tooth fracture.

  17. Assessment of XM-19 as a Substitute for AISI 348 in ATR Service

    SciTech Connect

    F. A. Garner; L. R. Greenwood; R. E. Mizia; C. R. Tyler

    2007-11-01

    It has been proposed that XM-19 alloy be considered as a possible replacement steel for AISI 348 in the construction of Advanced Test Reactor (ATR) capsules. AISI 348 works well, but is currently very difficult to obtain commercially. The superior and desirable mechanical properties of XM-19 alloy have been proven in non-nuclear applications, but no data are available regarding its use in radiation environments. While most 300 series alloys will meet the conditions required in ATR , it cannot be confidently assumed that XM-19 can be substituted without prior qualification in a radiation test. Compared to AISI 348, XM-19 will have an enhanced tendency for phase instabilities due to its higher levels of Ni and, especially, Si. However, transmutation of important elemental components in the highly thermalized ATR spectrum may have a very pronounced effect on its performance during irradiation. Not only will strong transmutation of Mn to Fe reduce the ductility and strength advantages provided by the higher initial Mn content of XM-19, but the extensive loss of Mn will also release from solution much of the N upon which the higher strength of XM-19 depends. In addition, the combined influence of transmutation and Inverse Kirkendall processes may lead to gas-bubble-covered grain boundaries, producing a very fragile alloy after significant irradiation has accumulated. At present, there are no radiation data available to substantiate this possible scenario. An alternate proposal is therefore advanced. Since the response of AISI 348 and 347 to radiation are expected to be relatively indistinguishable, the AISI 347 might serve as an acceptable replacement. While AISI 348 is usually chosen for nuclear service in order to reduce the overall radioactivity arising from relatively small amounts of highly transmutable elements such as cobalt, these elements have very little effect on the radiation performance of the steel. In the proposed application, however, the activity

  18. Behavior of AISI SAE 1020 Steel Implanted by Titanium and Exposed to Bacteria Sulphate Deoxidizer

    NASA Astrophysics Data System (ADS)

    Niño, Ely Dannier V.; Garnica, Hernán; Dugar-Zhabon, Veleriy; Castillo, Genis

    2014-05-01

    A hybrid technology to treat solid surfaces with the pulse high voltage and electric arc discharges of low pressure with a three-dimensional ion implantation technique (3DII) is applied. This technology is used to protect AISI SAE 1020 steel against a microbiological corrosion. The titanium ion implanted steel samples (coupons) are subjected to a medium of bacteria sulphate deoxidizer (BSD) which are very typical of the hydrocarbon industry and are potentially harmful for structures when are in contact with petroleum and some of its derivatives. The used technology aims to find an effective hybrid procedure to minimize the harmful effects of bacteria on AISI SAE 1020 steel. The hybrid technology efficiency of superficial titanium implantation is estimated through the measurements of the point corrosion characteristics obtained after testing both the treated and non-treated coupons. The three-dimensional surface structures of the samples are reconstructed with help of a confocal microscope.

  19. An investigation of the plastic fracture of AISI 4340 and 18 nickel - 200 grade maraging steels

    NASA Technical Reports Server (NTRS)

    Cox, T. B.; Low, J. R., Jr.

    1974-01-01

    The mechanisms of plastic fracture (dimpled rupture) in high-purity and commercial 18 Ni, 200 grade maraging steels and quenched and tempered AISI 4340 steels have been studied. Plastic fracture takes place in the maraging alloys through void initiation by fracture of titanium carbo-nitride inclusions and the growth of these voids until impingement results in coalescence and final fracture. The fracture of AISI 4340 steel at a yield strength of 200 ksi occurs by nucleation and subsequent growth of voids formed by fracture of the interface between manganese sulfide inclusions and the matrix. The growth of these inclusion-nucleated voids is interrupted long before coalescence by impingement, by the formation of void sheets which connect neighboring sulfide-nucleated voids.

  20. Radiation-induced evolution of austenite matrix in silicon-modified AISI 316 alloys

    SciTech Connect

    Garner, F.A.; Brager, H.R.

    1980-01-01

    The microstructures of a series of silicon-modified AISI 316 alloys irradiated to fast neutron fluences of about 2-3 and 10 x 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV at temperatures ranging from 400/sup 0/C to 600/sup 0/C have been examined. The irradiation of AISI 316 leads to an extensive repartition of several elements, particularly nickel and silicon, between the matrix and various precipitate phases. The segregation of nickel at void and grain boundary surfaces at the expense of other faster-diffusing elements is a clear indication that one of the mechanisms driving the microchemical evolution is the Inverse Kirkendall effect. There is evidence that at one sink this mechanism is in competition with the solute drag process associated with interstitial gradients.

  1. Vacancy clustering behavior in hydrogen-charged martensitic steel AISI 410 under tensile deformation

    NASA Astrophysics Data System (ADS)

    Sugita, K.; Mutou, Y.; Shirai, Y.

    2016-01-01

    The formation and accumulation of defects under tensile deformation of hydrogen- charged AISI 410 martensitic steels were investigated by using positron lifetime spectroscopy. During the deformation process, dislocations and vacancy-clusters were introduced and increased with increasing strains. Between hydrogen-charged and uncharged samples with the same tensile strains there was no significant difference in the dislocation density and monovacancy equivalent vacancy density.

  2. Stress corrosion cracking of AISI 321 stainless steel in acidic seawater

    NASA Astrophysics Data System (ADS)

    Huang, Yan-Liang; Hou, Bao-Rong; Cao, Chu-Nan; Lin, Hai-Chao

    1997-12-01

    The stress corrosion cracking (SCC) of AISI 321 stainless steel in acidic in acidic seawater was studied by slow strain rate (SSR) technique and fracture mechanics method. The fractured surface was characterized by cleavage fracture. The inhibiting effects of KI on SCC behavior were also covered in this detailed study which showed that they were mainly attributable to their inhibition on anodic reaction. The SCC mechanism study supported the unified mechanism of SCC and corrosion fatigue cracking (CFC).

  3. Experimental investigation of wear characteristics on TiCN-coated AISI 410 steel

    NASA Astrophysics Data System (ADS)

    Prabakaran, Vijayasarathi; Sivakumaran, Ilaiyavel; Palimar, Suresh Prabhu

    2016-04-01

    In this work, the dry sliding wear test of uncoated and multilayer TiCN-coated AISI 410 steel against high carbon steel disc recognized at 2.30267 ms-1 sliding speeds and under a three series load of 5, 10 and 20 N at room temperature. On account of the more coherent interface between TiCN and C probably found, there are high hardness and superior wear resistance. Compared to AISI 410 uncoated steel, the presence of C in the multilayer TiCN coatings leads to reduced coefficient of friction and wear loss. The multilayer TiCN coating is characterized by X-ray diffraction analysis, scanning electron microscopy, micro-hardness and pin-on-disc tribometer tests. The more grooving region, pits and ploughing ridge were examined on the worn surface of the AISI 410 uncoated steel. The result shows hard multilayer TiCN-coated particles viewing on the worn surface of the high carbon steel disc.

  4. Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

    NASA Astrophysics Data System (ADS)

    Hartwig, A.; Decker, M.; Klein, O.; Karl, H.

    2015-12-01

    The aim of this study is to evaluate the applicability of highly chemically inert titanium dioxide synthesized by ion beam implantation for corrosion protection of AISI 304 stainless steel in sodium chloride solution. More specifically, the prevention of galvanic corrosion between carbon-fiber reinforced plastic (CFRP) and AISI 304 was investigated. Corrosion performance of TiO2 implanted AISI 304 - examined for different implantation and annealing parameters - is strongly influenced by implantation fluence. Experimental results show that a fluence of 5 × 1016 cm-2 (Ti+) and 1 × 1017 cm-2 (O+) is sufficient to prevent pitting corrosion significantly, while galvanic corrosion with CFRP can already be noticeably reduced by an implantation fluence of 5 × 1015 cm-2 (Ti+) and 1 × 1016 cm-2 (O+). Surface roughness, implantation energy and annealing at 200 °C and 400 °C show only little influence on the corrosion behavior. TEM analysis indicates the existence of stoichiometric TiO2 inside the steel matrix for medium fluences and the formation of a separated metal oxide layer for high fluences.

  5. Nanoscale precipitates and comprehensive strengthening mechanism in AISI H13 steel

    NASA Astrophysics Data System (ADS)

    Mao, Wen-wen; Ning, An-gang; Guo, Han-jie

    2016-09-01

    The effects of heat treatment on the precipitates and strengthening mechanism in AISI H13 steel were investigated. The results showed that the presence of nanoscale precipitates favorably affected grain refinement and improved the yield strength. The volume fraction of precipitates increased from 1.05% to 2.85% during tempering, whereas the average precipitate size first decreased then increased during tempering. Contributions to the yield strength arising from the various mechanisms were calculated quantificationally, and the results demonstrated that grain refinement and dislocation density most strongly influenced the yield strength. In addition, under the interaction of average size and volume fraction, precipitates' contribution to the yield strength ranged from 247.9 to 378.5 MPa. Finally, a root-mean-square summation law of σ = σg + σs + (σd 2 + σp 2)1/2, where σg, σs, σd, and σp represent the contributions of fine-grain strengthening, solid-solution strengthening, dislocation strengthening, and precipitation strengthening, respectively, was confirmed as the most applicable for AISI H13 steel, which indicates a strong link between precipitates and dislocations in AISI H13 steel.

  6. Wear Evaluation of AISI 4140 Alloy Steel with WC/C Lamellar Coatings Sliding Against EN 8 Using Taguchi Method

    NASA Astrophysics Data System (ADS)

    Kadam, Nikhil Rajendra; Karthikeyan, Ganesarethinam

    2016-06-01

    The purpose of the experiments in this paper is to use the Taguchi methods to investigate the wear of WC/C coated nitrided AISI 4140 alloy steel. A study of lamellar WC/C coating which were deposited by a physical vapor deposition on nitrided AISI 4140 alloy steel. The investigation includes wear evaluation using Pin-on-disk configuration. When WC/C coated AISI 4140 alloy steel slides against EN 8 steel, it was found that carbon-rich coatings show much lower wear of the countersurface than nitrogen-rich coatings. The results were correlated with the properties determined from tribological and mechanical characterization, therefore by probably selecting the proper processing parameters the deposition of WC/C coating results in decreasing the wear rate of the substrate which shows a potential for tribological application.

  7. Endurance and failure characteristics of modified Vasco X-2, CBS 600 and AISI 9310 spur gears. [aircraft construction materials

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Zaretsky, E. V.

    1980-01-01

    Gear endurance tests and rolling-element fatigue tests were conducted to compare the performance of spur gears made from AISI 9310, CBS 600 and modified Vasco X-2 and to compare the pitting fatigue lives of these three materials. Gears manufactured from CBS 600 exhibited lives longer than those manufactured from AISI 9310. However, rolling-element fatigue tests resulted in statistically equivalent lives. Modified Vasco X-2 exhibited statistically equivalent lives to AISI 9310. CBS 600 and modified Vasco X-2 gears exhibited the potential of tooth fracture occurring at a tooth surface fatigue pit. Case carburization of all gear surfaces for the modified Vasco X-2 gears results in fracture at the tips of the gears.

  8. Investigating early stages of biocorrosion with XPS: AISI 304 stainless steel exposed to Burkholderia species

    NASA Astrophysics Data System (ADS)

    Johansson, Leena-Sisko; Saastamoinen, Tuomas

    1999-04-01

    We have investigated the interactions of an exopolymer-producing bacteria, Burkholderia sp. with polished AISI 304 stainless steel substrates using X-ray photoelectron spectroscopy (XPS). Steel coupons were exposed to the pure bacteria culture in a specially designed flowcell for 6 h during which the experiment was monitored in situ with an optical microscope. XPS results verified the formation of biofilm containing extracellular polymer on all the samples exposed to bacteria. Sputter results indicated that some ions needed for metabolic processes were trapped within the biofilm. Changes in the relative Fe concentration and Fe 2p peak shape indicated that also iron had accumulated into the biofilm.

  9. Martensitic stainless steel AISI 420—mechanical properties, creep and fracture toughness

    NASA Astrophysics Data System (ADS)

    Brnic, J.; Turkalj, G.; Canadija, M.; Lanc, D.; Krscanski, S.

    2011-11-01

    In this paper some experimental results and analyses regarding the behavior of AISI 420 martensitic stainless steel under different environmental conditions are presented. That way, mechanical properties like ultimate tensile strength and 0.2 percent offset yield strength at lowered and elevated temperatures as well as short-time creep behavior for selected stress levels at selected elevated temperatures of mentioned material are shown. The temperature effect on mentioned mechanical properties is also presented. Fracture toughness was calculated on the basis of Charpy impact energy. Experimentally obtained results can be of importance for structure designers.

  10. AISI/DOE Advanced Process Control Program Vol. 6 of 6: Temperature Measurement of Galvanneal Steel

    SciTech Connect

    S.W. Allison; D.L. Beshears; W.W. Manges

    1999-06-30

    This report describes the successful completion of the development of an accurate in-process measurement instrument for galvanneal steel surface temperatures. This achievement results from a joint research effort that is a part of the American Iron and Steel Institute's (AISI) Advanced Process Control Program, a collaboration between the U.S> Department of Energy and fifteen North American Steelmakers. This three-year project entitled ''Temperature Measurement of Galvanneal Steel'' uses phosphor thermography, and outgrowth of Uranium enrichment research at Oak Ridge facilities. Temperature is the controlling factor regarding the distribution of iron and zinc in the galvanneal strip coating, which in turn determines the desired product properties

  11. Prediction of Phase Transformation and Hardness Distribution of AISI 1045 Steel After Spot Continual Induction Hardening

    NASA Astrophysics Data System (ADS)

    Zhu, Shengxiao; Wang, Zhou; Qin, Xunpeng; Mao, Huajie; Gao, Kai

    2015-10-01

    An numerical and experimental study of spot continual induction hardening (SCIH) for AISI 1045 steel was carried out to gain a better understanding of this non-stationary and transverse flux induction hardening treatment. The SCIH device was set up by assembling the single-turn coil inductor to a five-axis cooperating computer numerical control system. The influence of inductor velocity, input current, and quenching medium on temperature field was estimated via the SCIH model, and the simulated micro-hardness and microstructure were validated by experimental verification. The heating delay phenomenon appearing in the SCIH process had been analyzed.

  12. Experimental Design and Data collection of a finishing end milling operation of AISI 1045 steel

    PubMed Central

    Dias Lopes, Luiz Gustavo; de Brito, Tarcísio Gonçalves; de Paiva, Anderson Paulo; Peruchi, Rogério Santana; Balestrassi, Pedro Paulo

    2016-01-01

    In this Data in Brief paper, a central composite experimental design was planned to collect the surface roughness of an end milling operation of AISI 1045 steel. The surface roughness values are supposed to suffer some kind of variation due to the action of several factors. The main objective here was to present a multivariate experimental design and data collection including control factors, noise factors, and two correlated responses, capable of achieving a reduced surface roughness with minimal variance. Lopes et al. (2016) [1], for example, explores the influence of noise factors on the process performance. PMID:26909374

  13. Wear behavior of AISI 1090 steel modified by pulse plasma technique

    SciTech Connect

    Ayday, Aysun; Durman, Mehmet

    2012-09-06

    AISI 1090 steel was pulse plasma treated (PPT) using a Molybdenum electrode. Two different pulse numbers were chosen to obtain modified layers of 20{+-}5 {mu}m thickness. The dry sliding wear studies performed on this steel with and without PPT against an alumina ball counterpart showed that the PPT improved the wear resistance. The pulse number of the PPT modified layer was found to be highly influential in imparting the wear resistance to this steel, due to enhancement of surface hardness depending on treatment time.

  14. Study of passive films formed on AISI 304 stainless steel by impedance measurements and photoelectrochemistry

    SciTech Connect

    Simoes, A.M.P.; Ferreiro, M.G.S. ); Rondot, B.; Belo, M. . Centre d'Etudes de Chimie Metallurgique)

    1990-01-01

    Moss-Schottky plots and photoelectrochemical measurements were made on films formed at different potentials on AISI 304 stainless steel in a borate/boric acid solution, pH 9.2. The results allowed the determination of the semiconductive properties and band structure of the films, which account for the existence of two kinds of films depending on the formation potential. For potentials below 0 V (SCE), the results point out for a film with an inverse spinel structure constituted by Cr-substituted magnetite with two donor levels. Above 0 V only one donor level is detected, which should be Fe{sup 2 +} on tetrahedral sites.

  15. Microstructural Evolution and Wear Resistance of Friction Stir-Processed AISI 52100 Steel

    NASA Astrophysics Data System (ADS)

    Seraj, R. A.; Abdollah-zadeh, A.; Hajian, M.; Kargar, F.; Soltanalizadeh, R.

    2016-07-01

    Friction stir processing (FSP) was successfully applied on AISI 52100 steel. The influence of process parameters on the microstructure and mechanical properties of the material was evaluated. It was observed that the initial ferritic-pearlitic microstructure of the base metal is transformed to the martensitic microstructure with retained austenite in the stir zone. The results also showed that microhardness and wear resistance of the FSP samples are, respectively, at least 2 and 15 times higher than those of the base metal. The improvement of the mechanical properties of FSP samples was attributed to their microstructural characteristics. The mechanisms controlling the wear behavior of the base metal and FSP samples were also discussed.

  16. Measurements on cracktips in stainless steel AISI 321 by using a new positron microprobe

    NASA Astrophysics Data System (ADS)

    Haaks, M.; Bennewitz, K.; Bihr, H.; Männig, U.; Zamponi, C.; Maier, K.

    1999-08-01

    High resolution positron microscopy provides a new method for non-destructive investigations of plastic deformation with spatial resolution in the micron range. As positron annihilation is highly sensitive to lattice defects, low concentrations of dislocations are detectable, so that the plastic zone in front of a cracktip appears larger than in comparable metallographic methods. To demonstrate this, a plastic zone in the common stainless steel AISI 321 is imaged with the Bonn Positron Microprobe (BPM) with a spatial resolution of 20 μm.

  17. Electrochemistry of galvanic couples between carbon and common metallic biomaterials in the presence of crevices.

    PubMed

    Silva, R A; Barbosa, M A; Jenkins, G M; Sutherland, I

    1990-07-01

    In vitro experiments were conducted upon some common metallic biomaterials and carbons, both isolated or forming galvanic couples, in a cell specially designed for crevice corrosion studies. The alloys examined were AISI 316L stainless steel, Ti6AI4V and Co-Cr-Mo. The types of carbon were glassy carbon and carbon fibre-reinforced carbon. The surface modifications were evaluated by SEM, AES and ESCA-XPS analyses. AISI 316L stainless steel suffered localized corrosion in open-circuit experiments whilst the other materials remained unattacked. Galvanic currents between metal-carbon couples were measured by zero resistance ammetry. The carbon-metal area ratio was 1:1. The results showed that 316L stainless steel and the Co-Cr-Mo alloy were prone to accelerated corrosion, whilst the Ti6AI4V alloy remained unattacked. The galvanic corrosion currents were also predicted using mixed potential theory from polarization curves obtained for each material. The experimental and theoretical values showed good agreement for the stainless steel and Co-Cr-Mo alloy. Long-term immersion tests with the same couples showed that the only metal not to suffer degradation was the Ti6AI4V alloy.

  18. Influence of dissolved hydrogen on the fatigue crack growth behaviour of AISI 4140 steel

    NASA Astrophysics Data System (ADS)

    Ramasagara Nagarajan, Varun

    Many metallic structural components come into contact with hydrogen during manufacturing processes or forming operations such as hot stamping of auto body frames and while in service. This interaction of metallic parts with hydrogen can occur due to various reasons such as water molecule dissociation during plating operations, interaction with atmospheric hydrogen due to the moisture present in air during stamping operations or due to prevailing conditions in service (e.g.: acidic or marine environments). Hydrogen, being much smaller in size compared to other metallic elements such as Iron in steels, can enter the material and become dissolved in the matrix. It can lodge itself in interstitials locations of the metal atoms, at vacancies or dislocations in the metallic matrix or at grain boundaries or inclusions (impurities) in the alloy. This dissolved hydrogen can affect the functional life of these structural components leading to catastrophic failures in mission critical applications resulting in loss of lives and structural component. Therefore, it is very important to understand the influence of the dissolved hydrogen on the failure of these structural materials due to cyclic loading (fatigue). For the next generation of hydrogen based fuel cell vehicles and energy systems, it is very crucial to develop structural materials for hydrogen storage and containment which are highly resistant to hydrogen embrittlement. These materials should also be able to provide good long term life in cyclic loading, without undergoing degradation, even when exposed to hydrogen rich environments for extended periods of time. The primary focus of this investigation was to examine the influence of dissolved hydrogen on the fatigue crack growth behaviour of a commercially available high strength medium carbon low alloy (AISI 4140) steel. The secondary objective was to examine the influence of microstructure on the fatigue crack growth behaviour of this material and to determine the

  19. Surface Treatments for Improved Performance of Spinel-coated AISI 441 Ferritic Stainless Steel

    SciTech Connect

    Stevenson, Jeffry W.; Riel, Eric M.; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2013-01-01

    Ferritic stainless steels are promising candidates for IT-SOFC interconnect applications due to their low cost and resistance to oxidation at SOFC operating temperatures. However, steel candidates face several challenges; including long term oxidation under interconnect exposure conditions, which can lead to increased electrical resistance, surface instability, and poisoning of cathodes due to volatilization of Cr. To potentially extend interconnect lifetime and improve performance, a variety of surface treatments were performed on AISI 441 ferritic stainless steel coupons prior to application of a protective spinel coating. The coated coupons were then subjected to oxidation testing at 800 and 850°C in air, and electrical testing at 800°C in air. While all of the surface-treatments resulted in improved surface stability (i.e., increased spallation resistance) compared to untreated AISI 441, the greatest degree of improvement (through 20,000 hours of testing at 800°C and 14,000 hours of testing at 850°C) was achieved by surface blasting.

  20. Niobium boride layers deposition on the surface AISI D2 steel by a duplex treatment

    SciTech Connect

    Kon, O.; Pazarlioglu, S.

    2015-03-30

    In this paper, we investigated the possibility of deposition of niobium boride layers on the surface of AISI D2 steel by a duplex treatment. At the first step of duplex treatment, boronizing was performed on AISI D2 steel samples at 1000{sup o}C for 2h and then pre-boronized samples niobized at 850°C, 900°C and 950°C using thermo-reactive deposition method for 1–4 h. The presence of the niobium boride layers such as NbB, NbB{sub 2} and Nb{sub 3}B{sub 4} and also iron boride phases such as FeB, Fe{sub 2}B were examined by X-ray diffraction analysis. Scanning electron microscope (SEM) and micro-hardness measurements were realized. Experimental studies showed that the depth of the coating layers increased with increasing temperature and times and also ranged from 0.42 µm to 2.43 µm, depending on treatment time and temperature. The hardness of the niobium boride layer was 2620±180 HV{sub 0.005}.

  1. Modeling of the flow stress for AISI H13 Tool Steel during Hard Machining Processes

    NASA Astrophysics Data System (ADS)

    Umbrello, Domenico; Rizzuti, Stefania; Outeiro, José C.; Shivpuri, Rajiv

    2007-04-01

    In general, the flow stress models used in computer simulation of machining processes are a function of effective strain, effective strain rate and temperature developed during the cutting process. However, these models do not adequately describe the material behavior in hard machining, where a range of material hardness between 45 and 60 HRC are used. Thus, depending on the specific material hardness different material models must be used in modeling the cutting process. This paper describes the development of a hardness-based flow stress and fracture models for the AISI H13 tool steel, which can be applied for range of material hardness mentioned above. These models were implemented in a non-isothermal viscoplastic numerical model to simulate the machining process for AISI H13 with various hardness values and applying different cutting regime parameters. Predicted results are validated by comparing them with experimental results found in the literature. They are found to predict reasonably well the cutting forces as well as the change in chip morphology from continuous to segmented chip as the material hardness change.

  2. Modelling of Tool Wear and Residual Stress during Machining of AISI H13 Tool Steel

    NASA Astrophysics Data System (ADS)

    Outeiro, José C.; Umbrello, Domenico; Pina, José C.; Rizzuti, Stefania

    2007-05-01

    Residual stresses can enhance or impair the ability of a component to withstand loading conditions in service (fatigue, creep, stress corrosion cracking, etc.), depending on their nature: compressive or tensile, respectively. This poses enormous problems in structural assembly as this affects the structural integrity of the whole part. In addition, tool wear issues are of critical importance in manufacturing since these affect component quality, tool life and machining cost. Therefore, prediction and control of both tool wear and the residual stresses in machining are absolutely necessary. In this work, a two-dimensional Finite Element model using an implicit Lagrangian formulation with an automatic remeshing was applied to simulate the orthogonal cutting process of AISI H13 tool steel. To validate such model the predicted and experimentally measured chip geometry, cutting forces, temperatures, tool wear and residual stresses on the machined affected layers were compared. The proposed FE model allowed us to investigate the influence of tool geometry, cutting regime parameters and tool wear on residual stress distribution in the machined surface and subsurface of AISI H13 tool steel. The obtained results permit to conclude that in order to reduce the magnitude of surface residual stresses, the cutting speed should be increased, the uncut chip thickness (or feed) should be reduced and machining with honed tools having large cutting edge radii produce better results than chamfered tools. Moreover, increasing tool wear increases the magnitude of surface residual stresses.

  3. Void Swelling Of Aisi 321 Analog Stainless Steel Irradiated At Low Dpa Rates In The Bn-350 Reactor

    SciTech Connect

    Maksimkin, O. P.; Tsai, K. V.; Turubarova, L. G.; Doronina, T. A.; Garner, Francis A.

    2006-03-01

    In several recently published studies conducted on a Soviet analog of AISI 321 stainless steel irradiated in either fast reactors or light water reactors, it was shown that the void swelling phenomenon extended to temperatures as low as ~300ºC or less, when produced by neutron irradiation at dpa rates in the range 10-7 to 10-8 dpa/sec. Other studies yielded similar results for AISI 316 and the Russian analog of AISI 316. In the current study a blanket duct assembly from BN-350, constructed from the Soviet analog of AISI 321, also exhibits swelling at dpa rates on the order of 10-8 dpa/sec, with voids seen as low as 281oC and only 0.65 dpa. It appears that low-temperature swelling occurs at low dpa rates in 300 series stainless steels in general, and also occurs during irradiations conducted in either fast or mixed spectrum reactors. Therefore it is expected that a similar behavior will be observed in fusion devices as well.

  4. Void Swelling of AISI 321 Analog Stainless Steel Irradiated at Low DPA Rates in the BN-350 Reactor

    SciTech Connect

    Maksimkin, O. P.; Tsai, K. V.; Turubarova, L. G.; Doronina, T. A.; Garner, Francis A.

    2007-08-01

    In several recently published studies conducted on a Soviet analog of AISI 321 stainless steel irradiated in either fast reactors or light water reactors, it was shown that the void swelling phenomenon extended to temperatures as low as ~300ºC or less, when produced by neutron irradiation at dpa rates in the range 10-7 to 10-8 dpa/sec. Other studies yielded similar results for AISI 316 and the Russian analog of AISI 316. In the current study a blanket duct assembly from BN-350, constructed from the Soviet analog of AISI 321, also exhibits swelling at dpa rates on the order of 10-8 dpa/sec, with voids seen as low as 281C and only 0.65 dpa. It appears that low-temperature swelling occurs at low dpa rates in 300 series stainless steels in general, and also occurs during irradiations conducted in either fast or in mixed spectrum reactors as shown in other studies.

  5. Studies on the determination of surface deuterium in AISI 1062, 4037, and 4140 steels by secondary ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Sastri, V. S.; Donepudi, V. S.; McIntyre, N. S.; Johnston, D.; Revie, R. W.

    1988-12-01

    The concentration of deuterium at the surface of cathodically charged high strength steels AISI 1062, 4037, and 4140 has been determined by secondary ion mass spectrometry (SIMS). The beneficial effects of pickling in NAP (a mixture of nitric, acetic, and phosphoric acids) to remove surfacebound deuterium have been observed.

  6. Effects of Ultrasonic Nanocrystal Surface Modification (UNSM) on Residual Stress State and Fatigue Strength of AISI 304

    NASA Astrophysics Data System (ADS)

    Cherif, A.; Pyoun, Y.; Scholtes, B.

    2010-03-01

    The effects of a new mechanical surface treatment method, called ultrasonic nanocrystal surface modification (UNSM), on near-surface microstructures and residual stress states as well as on the fatigue behavior of an austenitic steel AISI 304 are investigated and discussed. The results are compared with consequences of other mechanical surface treatment methods such as deep rolling or shot peening.

  7. Void swelling of AISI 321 analog stainless steel irradiated at low dpa rates in the BN-350 reactor

    NASA Astrophysics Data System (ADS)

    Maksimkin, O. P.; Tsai, K. V.; Turubarova, L. G.; Doronina, T.; Garner, F. A.

    2007-08-01

    In several recently published studies conducted on a Soviet analog of AISI 321 stainless steel irradiated in either fast reactors or light water reactors, it was shown that the void swelling phenomenon extended to temperatures as low as ˜300 °C or less, when produced by neutron irradiation at dpa rates in the range 10 -7-10 -8 dpa/s. Other studies yielded similar results for AISI 316 and the Russian analog of AISI 316. In the current study a blanket assembly duct from BN-350, constructed from the Soviet analog of AISI 321, also exhibits swelling at dpa rates on the order of 10 -8 dpa/s, with voids seen as low as 281 °C and only 0.65 dpa. It appears that low-temperature swelling occurs at low dpa rates in 300 series stainless steels in general, and also occurs during irradiations conducted in either fast or in mixed spectrum reactors as shown in other studies.

  8. Corrosion testing of type 304L stainless steel in tuff groundwater environments

    SciTech Connect

    Westerman, R.E.; Pitman, S.G.; Haberman, J.H.

    1987-11-01

    The stress-corrosion cracking (SCC) resistance of Type 304L stainless steel (SS) to elevated temperatures in tuff rock and tuff groundwater environments was determined under irradiated and nonirradiated conditions using U-bend specimens and slow-strain-rate tests. The steel was tested both in the solution-annealed condition and after sensitization heat treatments. The material was found to be susceptible to SCC in both the solution-annealed and solution-annealed-and-sensitized conditions when exposed to an irradiated crushed tuff rock environment containing air and water vapor at 90{sup 0}C. A similar exposure at 50{sup 0}C did not result in failure after a 25-month test duration. Specimens of sensitized 304 SS conditioned with a variety of sensitization heat treatments resisted failure during a test of 1-year duration in which a nonirradiated environment of tuff rock and groundwater held at 200{sup 0}C was allowed to boil to dryness on a cyclical basis. All specimens of sensitized 304 SS exposed to this environment failed. Slow-strain-rate studies were performed on 304L, 304, and 316L SS specimens. The 304L SS was tested in J-13 well water at 150{sup 0}C, and the 316L SS at 95{sup 0}C. Neither material showed evidence of SCC in these tests. Sensitized 304 SS did exhibit SCC in J-13 well water in tests conducted at 150{sup 0}C. 12 refs., 27 figs., 13 tabs.

  9. Influence of alumina and titanium dioxide coatings on abrasive wear resistance of AISI 1045 steel

    NASA Astrophysics Data System (ADS)

    Santos, A.; Remolina, A.; Marulanda, J.

    2016-02-01

    This project aims to compare the behaviour of an AISI 1045 steel's abrasive wear resistance when is covered with aluminium oxide (Al2O3) or Titanium dioxide (TiO2), of nanometric size, using the technique of thermal hot spray, which allows to directly project the suspension particles on the used substrate. The tests are performed based on the ASTM G65-04 standard (Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Apparatus). The results show that the amount of, lost material increases linearly with the travelled distance; also determined that the thermal treatment of hardening-tempering and the alumina and titanium dioxide coatings decrease in average a 12.9, 39.6 and 29.3% respectively the volume of released material during abrasive wear test.

  10. Effect of Plasma Nitriding Temperatures on Characteristics of Aisi 201 Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Gao, Yuxin; Zheng, Shaomei

    2016-10-01

    Samples of AISI 201 austenitic stainless steel were produced by plasma nitriding at 350∘C, 390∘C, 420∘C, 450∘C and 480∘C for 5h. Systematic characterization of the nitrided layer was carried out in terms of micrograph observations, phase identification, chemical composition depth profiling, surface microhardness measurements and electrochemical corrosion tests. The results show that the surface hardness and the layer thickness increased with increasing temperature. XRD indicated that a single S-phase layer was formed during low temperature (≤420∘C), while Cr2N or CrN phase was formed besides S-phase when nitrided at 450∘C and 480∘C. The specimen treated at 390∘C presents a much enhanced corrosion resistance compared to the untreated substrate. The corrosion resistance deteriorated for samples treated above 450∘C due to the formation of chromium nitrides.

  11. Acoustic emission studies on welded and thermally treated AISI 304 stainless steel during tensile deformation

    SciTech Connect

    Mukherjee, P.; Barat, P.; Jayakumar, T.; Kalyanasundaram, P.; Rajagopalan, C.; Raj, B.

    1997-10-15

    The present investigations are planned to study the influence of prior martensites formed due to cold treatment as 77K in AISI 304 SS welded specimens, on strain-induced martensites occurred during tensile deformation using AE technique. AE parameters like count rate and root mean square (r.m.s.) voltage have been used to characterize AE activities generated during tensile deformation process in as-welded and welded-treated samples. Frequency spectrum analysis of AE signals captured from the samples has been done to understand the dynamic behavior of the martensite phase formation. Tensile properties of these samples have also been reported. Volume fraction of the magnetic phase (martensite and delta ferrite) formed in these samples are measured before and after straining. X-ray diffraction (XRD) technique has been used to support the presence of delta ferrite (formed during welding) and martensite in the weld region.

  12. Residual Stresses in LENS-Deposited AISI 410 Stainless Steel Plates

    SciTech Connect

    Wang, L; Felicellli, S D; Pratt, Phillip R

    2008-01-01

    The residual stress in thin plate components deposited by the laser engineered net shaping (LENS{reg_sign}) process was investigated experimentally and numerically. Neutron diffraction mapping was used to characterize the residual stress in LENS-deposited AISI 410 stainless steel thin wall plates. Using the commercial welding software SYSWELD, a thermo-mechanical three-dimensional finite element model was developed, which considers also the effect of metallurgical phase transformations. The model was employed to predict the temperature history and the residual stress field during the LENS process. Several simulations were performed with the geometry and process parameters that were used to build the experimental samples. The origin of the residual stress distribution is discussed based on the thermal histories of the samples, and the modeling results are compared with measurements obtained by neutron diffraction mapping.

  13. Improving electrochemical properties of AISI 1045 steels by duplex surface treatment of plasma nitriding and aluminizing

    NASA Astrophysics Data System (ADS)

    Haftlang, Farahnaz; Habibolahzadeh, Ali; Sohi, Mahmoud Heydarzadeh

    2015-02-01

    Improvement in electrochemical behavior of AISI 1045 steel after applying aluminum nitride coating was investigated in 3.5% NaCl solution, using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) analyses. Aluminum nitride coating was applied on the steel surface by duplex treatment of pack aluminizing and plasma nitriding. Some specimens were plasma nitrided followed by aluminizing (PN-Al), while the others were pack aluminized followed by plasma nitriding (Al-PN). Topological and structural studies of the modified surfaces were conducted using scanning electron microscope (SEM) equipped by energy dispersive X-ray spectroscope (EDS), and X-ray diffractometer (XRD). The electrochemical measurements showed that the highest corrosion and polarization (Rp) resistances were obtained in PN-Al specimens, having single phase superficial layer of AlN. Pitting mechanism was dominant reason of lower corrosion resistance in the Al-PN specimens.

  14. Microstructure and Texture Evolutions in AISI 1050 Steel by Flow Forming

    SciTech Connect

    Bedekar, Vikram; Pauskar, Praveen; Shivpuri, Rajiv; Howe, Jane Y

    2014-01-01

    Hot rolled and annealed AISI 1050 steel cylindrical coupons were flow formed at different levels of deformation (66% and 90% wall thickness reduction). TEM studies revealed development of ultra fine (sub) grain cell structure due to severe plastic deformation. The transverse subgrain size changed from 10 m (beginning) to 300nm (66% deformation) to 40nm (90% deformation). EBSD study revealed decreased recrystallization fraction at 90% deformation compared with 66% deformation due to orientation pinning from preferred orientation along {002} planes. No evidence of dislocation pinning or cracking was observed on any samples. The aim of the present work is to study the deformation behaviour and microstructural evolution during conventional flow forming process. The study also sheds light on the strengthening behaviour and structural changes during severe straining.

  15. Ultrasonic and metallographic studies on AISI 4140 steel exposed to hydrogen at high pressure and temperature

    NASA Astrophysics Data System (ADS)

    Oruganti, Malavika

    This thesis conducts an investigation to study the effects of hydrogen exposure at high temperature and pressure on the behavior of AISI 4140 steel. Piezoelectric ultrasonic technique was primarily used to evaluate surface longitudinal wave velocity and defect geometry variations, as related to time after exposure to hydrogen at high temperature and pressure. Critically refracted longitudinal wave technique was used for the former and pulse-echo technique for the latter. Optical microscopy and scanning electron microscopy were used to correlate the ultrasonic results with the microstructure of the steel and to provide better insight into the steel behavior. The results of the investigation indicate that frequency analysis of the defect echo, determined using the pulse-echo technique at regular intervals of time, appears to be a promising tool for monitoring defect growth induced by a high temperature and high pressure hydrogen-related attack.

  16. Pitting fatigue characteristics of AISI M-50 and super nitralloy spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Chevalier, J. L.; Zaretsky, E. V.

    1973-01-01

    Two groups of 3.50-in. pitch-diameter spur gears, without tip relief, made from consumable-electrode vacuum-melted (CVM) AISI M-50 steel and CVM super nitralloy (5Ni-2A1) were tested under conditions which produced fatigue pitting. The M-50 gears had fatigue lives approximately 50 percent longer than the super nitralloy gears. Both groups of gears failed by classical rolling-element fatigue at the pitch circle. When the gears were overrun past initial spall formation, the spalled M-50 gear teeth failed by fatigue fracture. The M-50 material had higher wear than the super nitralloy material. Differences in fatigue life and wear were not considered statistically significant.

  17. Aluminum diffusion in Al-implanted AISI 321 stainless steel using accelerator-based characterization techniques

    NASA Astrophysics Data System (ADS)

    Noli, F.; Misaelides, P.; Bethge, K.

    1998-04-01

    The aluminum diffusion in near-surface layers of Al-implanted AISI 321 austenitic stainless steel (Fe/Cr18/Ni8/Ti) was studied using ion beam analysis techniques. The implanted samples were investigated at temperatures between 450°C and 650°C (treatment times up to 144 h in vacuum and in air). The Al-profiles were determined by the 992 keV resonance of the 27Al(p,γ) 28Si nuclear reaction as well as by 4He +-Rutherford Backscattering Spectrometry (RBS). The experimental diffusion coefficients, obtained during this study using Fick's second law, were compared with corresponding literature concerning the aluminum diffusion in other relevant metallic materials. The determination of the depth profiles contributes to the interpretation of the high temperature oxidation behavior of Al-implanted stainless steel surfaces.

  18. Influence of Laser Peening on Phase Transformation and Corrosion Resistance of AISI 321 steel

    NASA Astrophysics Data System (ADS)

    Karthik, D.; Swaroop, S.

    2016-07-01

    The objective of this study is to investigate the influence of laser peening without coating (LPwC) on austenitic to martensitic (γ → α') phase transformation and corrosion behavior of austenitic stainless steel AISI 321 in 3.5% NaCl environment. Results indicate that LPwC induces a large compressive residual stresses of nearly -854 MPa and γ → α' phase transformation of about 18% (volume fraction). Microstructures of peened surface confirmed the γ → α' phase transformation and showed no grain refinement. Hardness increased slightly with a case depth of 900 μm. Despite the smaller surface roughness introduced, corrosion resistance improved after peening due to compressive residual stresses.

  19. Experimental and numerical study on plasma nitriding of AISI P20 mold steel

    NASA Astrophysics Data System (ADS)

    Nayebpashaee, N.; Vafaeenezhad, H.; Kheirandish, Sh.; Soltanieh, M.

    2016-09-01

    In this study, plasma nitriding was used to fabricate a hard protective layer on AISI P20 steel, at three process temperatures (450°C, 500°C, and 550°C) and over a range of time periods (2.5, 5, 7.5, and 10 h), and at a fixed gas N2:H2 ratio of 75vol%:25vol%. The morphology of samples was studied using optical microscopy and scanning electron microscopy, and the formed phase of each sample was determined by X-ray diffraction. The elemental depth profile was measured by energy dispersive X-ray spectroscopy, wavelength dispersive spectroscopy, and glow dispersive spectroscopy. The hardness profile of the samples was identified, and the microhardness profile from the surface to the sample center was recorded. The results show that ɛ-nitride is the dominant species after carrying out plasma nitriding in all strategies and that the plasma nitriding process improves the hardness up to more than three times. It is found that as the time and temperature of the process increase, the hardness and hardness depth of the diffusion zone considerably increase. Furthermore, artificial neural networks were used to predict the effects of operational parameters on the mechanical properties of plastic mold steel. The plasma temperature, running time of imposition, and target distance to the sample surface were all used as network inputs; Vickers hardness measurements were given as the output of the model. The model accurately reproduced the experimental outcomes under different operational conditions; therefore, it can be used in the effective simulation of the plasma nitriding process in AISI P20 steel.

  20. Surface fatigue life of M50NiL and AISI 9310 spur gears and R C bars

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Bamberger, Eric N.

    1991-01-01

    Spur gear endurance tests and rolling element surface fatigue tests were conducted to study vacuum induction melted, vacuum arc remelted (VIM-VAR) M50NiL steel for use as a gear steel in advanced aircraft applications, to determine its endurance characteristics, and to compare the results with those for standard VAR and VIM-VAR AISI 9310 gear material. Tests were conducted with spur gears and rolling contact bars manufactured from VIM-VAR M50NiL and VAR and VIM-VAR AISI 9310. The gear pitch diameter was 8.9 cm. Gear test conditions were an inlet oil temperature of 320 K, and outlet oil temperature of 350 K, a maximum Hertz stress of 1.71 GPa, and a speed of 10000 rpm. Bench rolling element fatigue tests were conducted at ambient temperatures with a bar speed of 12,500 rpm and a maximum Hertz stress of 4.83 GPa. The VIM-VAR M50NiL gears had a surface fatigue life that was 4.5 and 11.5 times that for VIM-VAR and VAR AISI 9310 gears, respectively. The surface fatigue life of the VIM-VAR M50NiL rolling contact bars was 13.2 and 21.6 times that for the VIM-VAR and VAR AISI 9310, respectively. The VIM-VAR M50NiL material was shown to have good resistance to fracture through a fatigue spall and superior fatigue life to both other gears.

  1. Microstructure and Mechanical Properties of Laser Clad and Post-cladding Tempered AISI H13 Tool Steel

    NASA Astrophysics Data System (ADS)

    Telasang, Gururaj; Dutta Majumdar, Jyotsna; Wasekar, Nitin; Padmanabham, G.; Manna, Indranil

    2015-05-01

    This study reports a detailed investigation of the microstructure and mechanical properties (wear resistance and tensile strength) of hardened and tempered AISI H13 tool steel substrate following laser cladding with AISI H13 tool steel powder in as-clad and after post-cladding conventional bulk isothermal tempering [at 823 K (550 °C) for 2 hours] heat treatment. Laser cladding was carried out on AISI H13 tool steel substrate using a 6 kW continuous wave diode laser coupled with fiber delivering an energy density of 133 J/mm2 and equipped with a co-axial powder feeding nozzle capable of feeding powder at the rate of 13.3 × 10-3 g/mm2. Laser clad zone comprises martensite, retained austenite, and carbides, and measures an average hardness of 600 to 650 VHN. Subsequent isothermal tempering converted the microstructure into one with tempered martensite and uniform dispersion of carbides with a hardness of 550 to 650 VHN. Interestingly, laser cladding introduced residual compressive stress of 670 ± 15 MPa, which reduces to 580 ± 20 MPa following isothermal tempering. Micro-tensile testing with specimens machined from the clad zone across or transverse to cladding direction showed high strength but failure in brittle mode. On the other hand, similar testing with samples sectioned from the clad zone parallel or longitudinal to the direction of laser cladding prior to and after post-cladding tempering recorded lower strength but ductile failure with 4.7 and 8 pct elongation, respectively. Wear resistance of the laser surface clad and post-cladding tempered samples (evaluated by fretting wear testing) registered superior performance as compared to that of conventional hardened and tempered AISI H13 tool steel.

  2. Effect of coatings obtanied by sputtering of chromium catode on the corrosion resistance of AISI H13 steel

    NASA Astrophysics Data System (ADS)

    Sandoval, A.; Peña, D.; Piratoba, U.

    2013-11-01

    Corrosion resistance of coatings obtained by sputtering a chromium target were evaluated. The films were deposited on substrates of disk-shaped AISI H13 steel. By means of potentiodynamic polarization curves were able to determine the current density vs. potential for the coated and uncoated substrate and the difference in the corrosion potential Ecorr. All samples with coating showed an increase in Ecorr respect to substrate. The electrochemical tests were conducted in an electrolytic solution of 3% NaCl.

  3. Softening during and after the hot deformation of the AISI 321 steel with respect to practical applications

    NASA Astrophysics Data System (ADS)

    Havela, L.; Kratochvíl, P.; Lukáč, P.; Smola, B.; Svobodová, A.

    1988-04-01

    The softening processes during and after the hot deformation (850 1180 ‡C) in AISI 321 stainless steel were studied with respect to true strains ɛ D and true strain ratesdot \\varepsilon _D . The analysis of deformation curves indicates the occurrence of dynamic recrystallization for values of Zener-Hollomon parameter Z≈1015 s-1. The retardation of static recrystallization by fine Ti(N, C) precipitates is documented by microstructure studies and by variations of annealing conditions.

  4. Wear and Adhesive Failure of Al2O3 Powder Coating Sprayed onto AISI H13 Tool Steel Substrate

    NASA Astrophysics Data System (ADS)

    Amanov, Auezhan; Pyun, Young-Sik

    2016-07-01

    In this study, an alumina (Al2O3) ceramic powder was sprayed onto an AISI H13 hot-work tool steel substrate that was subjected to sanding and ultrasonic nanocrystalline surface modification (UNSM) treatment processes. The significance of the UNSM technique on the adhesive failure of the Al2O3 coating and on the hardness of the substrate was investigated. The adhesive failure of the coating sprayed onto sanded and UNSM-treated substrates was investigated by a micro-scratch tester at an incremental load. It was found, based on the obtained results, that the coating sprayed onto the UNSM-treated substrate exhibited a better resistance to adhesive failure in comparison with that of the coating sprayed onto the sanded substrate. Dry friction and wear property of the coatings sprayed onto the sanded and UNSM-treated substrates were assessed by means of a ball-on-disk tribometer against an AISI 52100 steel ball. It was demonstrated that the UNSM technique controllably improved the adhesive failure of the Al2O3 coating, where the critical load was improved by about 31%. Thus, it is expected that the application of the UNSM technique to an AISI H13 tool steel substrate prior to coating may delay the adhesive failure and improve the sticking between the coating and the substrate thanks to the modified and hardened surface.

  5. Plasma nitriding process by direct current glow discharge at low temperature increasing the thermal diffusivity of AISI 304 stainless steel

    SciTech Connect

    Prandel, L. V.; Somer, A.; Assmann, A.; Camelotti, F.; Costa, G.; Bonardi, C.; Jurelo, A. R.; Rodrigues, J. B.; Cruz, G. K.

    2013-02-14

    This work reports for the first time on the use of the open photoacoustic cell technique operating at very low frequencies and at room temperature to experimentally determine the thermal diffusivity parameter of commercial AISI304 stainless steel and AISI304 stainless steel nitrided samples. Complementary measurements of X-ray diffraction and scanning electron microscopy were also performed. The results show that in standard AISI 304 stainless steel samples the thermal diffusivity is (4.0 {+-} 0.3) Multiplication-Sign 10{sup -6} m{sup 2}/s. After the nitriding process, the thermal diffusivity increases to the value (7.1 {+-} 0.5) Multiplication-Sign 10{sup -6} m{sup 2}/s. The results are being associated to the diffusion process of nitrogen into the surface of the sample. Carrying out subsequent thermal treatment at 500 Degree-Sign C, the thermal diffusivity increases up to (12.0 {+-} 2) Multiplication-Sign 10{sup -6} m{sup 2}/s. Now the observed growing in the thermal diffusivity must be related to the change in the phases contained in the nitrided layer.

  6. Correlation between characteristics of grain boundary carbides and creep-fatigue properties in AISI 321 stainless steel

    NASA Astrophysics Data System (ADS)

    Min, Kyung Seon; Nam, Soo Woo

    2003-11-01

    The effects of the interfacial relationships between grain boundary carbides and neighboring grains on the creep-fatigue behaviors have been investigated in AISI 321 stainless steel. The contacting interfacial planes between grain boundary TiC and neighboring grains are found to have lower Miller indices than those between Cr 23C 6 and neighboring grains. From this observation, it is suggested that the interfacial free energy between grain boundary TiC and grains is lower than that between Cr 23C 6 and grains. Creep-fatigue life of TiC aged AISI 321 stainless steel is observed to be longer than that of Cr 23C 6 aged AISI 321 stainless steel. The differences in creep-fatigue life are based on the stronger cavitation resistance of TiC compared with that of Cr 23C 6. From the interfacial relationships between the grain boundary carbides and the neighboring grains, it is verified that formation and growth of grain boundary cavities at TiC carbides are more retarded than those at Cr 23C 6 carbides, thus extending the creep-fatigue life of the steel.

  7. Microstructure and corrosion resistance of nanocrystalline TiZrN films on AISI 304 stainless steel substrate

    SciTech Connect

    Lin, Yu-Wei; Huang, Jia-Hong; Yu, Ge-Ping

    2010-07-15

    This study investigated the microstructure and properties of nanocrystalline TiZrN films on AISI 304 stainless steel substrate. TiZrN films were prepared by reactive magnetron sputtering based on the previous optimum coating conditions (substrate temperature, system pressure, nitrogen flow, etc.) for TiN and ZrN thin films. The composition ratio of TiZrN coatings were adjusted by changing the Zr target power, while keeping the Ti target power constant. Experiments were conduced to find the optimum composition with desired properties. The ratio of TiZrN composition was analyzed by x-ray photoelectron spectroscopy and Rutherford backscattering spectrometer. In terms of phase formation, there were two types of coatings that were considered: single-phase solid solutions of TiZrN and interlacing nuclei of TiZr in the matrix of TiZrN. The thickness of all TiZrN films as measured by the secondary ion mass spectroscopy was about 500 nm, and the composition depth profiles indicated that the compositions in the TiZrN films were uniform from the film surface to the 304 stainless steel substrate. The crystal structure of the TiZrN films was determined by x-ray diffraction using a M18XHF-SRA diffractometer with Cu K{sub {alpha}} radiation. A diffraction peak of TiZrN (002) was observed between that of TiN (002) and ZrN (002); similarly, a diffraction peak of TiZrN (111) was observed between that of TiN(111) and ZrN(111), respectively. The corrosion resistance of the TiZrN film deposited on the 304 stainless steel has been investigated by electrochemical measurement. The electrolyte, 0.5M H{sub 2}SO{sub 4} containing 0.05M KSCN, was used for the potentiodynamic polarization. The potentiodynamic scan was conducted from -800 to 800 mV standard calomel electrode (SCE).

  8. Experimental Evaluation and Optimization of Flank Wear During Turning of AISI 4340 Steel with Coated Carbide Inserts Using Different Cutting Fluids

    NASA Astrophysics Data System (ADS)

    Lawal, S. A.; Choudhury, I. A.; Nukman, Y.

    2015-01-01

    The understanding of cutting fluids performance in turning process is very important in order to improve the efficiency of the process. This efficiency can be determined based on certain process parameters such as flank wear, cutting forces developed, temperature developed at the tool chip interface, surface roughness on the work piece, etc. In this study, the objective is to determine the influence of cutting fluids on flank wear during turning of AISI 4340 with coated carbide inserts. The performances of three types of cutting fluids were compared using Taguchi experimental method. The results show that palm kernel oil based cutting fluids performed better than the other two cutting fluids in reducing flank wear. Mathematical models for cutting parameters such as cutting speed, feed rate, depth of cut and cutting fluids were obtained from regression analysis using MINITAB 14 software to predict flank wear. Experiments were conducted based on the optimized values to validate the regression equations for flank wear and 5.82 % error was obtained. The optimal cutting parameters for the flank wear using S/N ratio were 160 m/min of cutting speed (level 1), 0.18 mm/rev of feed (level 1), 1.75 mm of depth of cut (level 2) and 2.97 mm2/s palm kernel oil based cutting fluid (level 3). ANOVA shows cutting speed of 85.36 %; and feed rate 4.81 %) as significant factors.

  9. Effects of Jet Pressure on the Ground Surface Quality and CBN Wheel Wear in Grinding AISI 690 Nickel-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Guitouni, Ahmed; Chaieb, Iheb; Rhouma, Amir Ben; Fredj, Nabil Ben

    2016-09-01

    Fluid application in grinding is getting attention as higher stock removal rates, higher surface integrity and longer wheel life are required. It is necessary to define proper conditions of application for meeting high productivity goals by lowering the specific grinding energy and reducing the temperature of the contact zone. The present study investigated the capacity of the jet pressure of a spot nozzle to improve the wear of a CBN wheel when grinding the AISI 690 superalloy. Grinding experiments were conducted with an emulsion-type cooling fluid delivered at pressure ranging from 0.1 to 4 MPa. Results show that the maximum stock removal, reached at 4 MPa, is 5 times the stock removal obtained at 0.1 MPa, while the grinding ratio at 4 MPa is 8 times that at 0.1 MPa, and there is a critical pressure (P c) around 1.5 MPa corresponding to the minimum specific grinding energy. Scanning electron microscopy of the grain tips showed that the wear mechanism shifts from breaking and dislodgment at low jet pressure to micro-fracture resulting in continuous self-sharpening of the abrasive grains. By lubricating at jet pressure close to P c, there is less thermal damage due to plowing and sliding and the resulting lower loading of the abrasive grains favors the micro-fracture of grains and thus a longer wheel life.

  10. New Alkylether-Thiazolium Room-Temperature Ionic Liquid Lubricants: Surface Interactions and Tribological Performance.

    PubMed

    Espinosa, Tulia; Sanes, José; Bermúdez, María-Dolores

    2016-07-20

    The use of newly synthesized alkylether-thiazolium ionic liquids as lubricants is described for the first time. Two ionic liquids composed of a thiazolium cation and a bis(trifluoromethanesulfonyl)amide ([Th][Tf2N]) or dicyanamide ([Th][(NC)2N]) anion have been studied, and their tribological behavior has been compared with that of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([Im][Tf2N]) in pin-on-disk tests using sapphire balls against AISI 52100 or AISI 316L steels. All ionic liquids show higher contact angles on AISI 316L steel than on AISI 52100, the lowest values found for ([Im][Tf2N]) on both steel surfaces. AISI 52100 shows similar friction coefficients for all lubricants, and negligible wear rates for the ionic liquids containing the bis(trifluoromethanesulfonyl)amide anion. Immersion tests show no corrosion of AISI 52100 in imidazolium or thiazolium bis(trifluoromethanesulfonyl)amide ionic liquids. AISI 316L shows similar friction coefficients for both bis(trifluoromethanesulfonyl)amide ionic liquids, but the lowest wear rate is obtained for [Th][Tf2N]. An increase in friction coefficient and wear rate is observed for thiazolium dicyanamide. This increase is related to a tribocorrosion process due to decomposition of the thiazolium cation. XPS shows the formation of iron sulfide on the wear track on AISI 316L after lubrication with thiazolium dicyanamide. No tribocorrosion processes take place for the [Tf2N] ionic liquids.

  11. New Alkylether-Thiazolium Room-Temperature Ionic Liquid Lubricants: Surface Interactions and Tribological Performance.

    PubMed

    Espinosa, Tulia; Sanes, José; Bermúdez, María-Dolores

    2016-07-20

    The use of newly synthesized alkylether-thiazolium ionic liquids as lubricants is described for the first time. Two ionic liquids composed of a thiazolium cation and a bis(trifluoromethanesulfonyl)amide ([Th][Tf2N]) or dicyanamide ([Th][(NC)2N]) anion have been studied, and their tribological behavior has been compared with that of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([Im][Tf2N]) in pin-on-disk tests using sapphire balls against AISI 52100 or AISI 316L steels. All ionic liquids show higher contact angles on AISI 316L steel than on AISI 52100, the lowest values found for ([Im][Tf2N]) on both steel surfaces. AISI 52100 shows similar friction coefficients for all lubricants, and negligible wear rates for the ionic liquids containing the bis(trifluoromethanesulfonyl)amide anion. Immersion tests show no corrosion of AISI 52100 in imidazolium or thiazolium bis(trifluoromethanesulfonyl)amide ionic liquids. AISI 316L shows similar friction coefficients for both bis(trifluoromethanesulfonyl)amide ionic liquids, but the lowest wear rate is obtained for [Th][Tf2N]. An increase in friction coefficient and wear rate is observed for thiazolium dicyanamide. This increase is related to a tribocorrosion process due to decomposition of the thiazolium cation. XPS shows the formation of iron sulfide on the wear track on AISI 316L after lubrication with thiazolium dicyanamide. No tribocorrosion processes take place for the [Tf2N] ionic liquids. PMID:27348604

  12. Effect of Surface Integrity of Hard Turned AISI 52100 Steel on Fatigue Performance

    SciTech Connect

    Lara-Curzio, Edgar; Watkins, Thomas R; Allard Jr, Lawrence Frederick; Riester, Laura

    2007-01-01

    This paper addresses the relationship between surface integrity and fatigue life of hard turned AISI 52100 steel (60-62 HRC), with grinding as a benchmark. The impact of superfinishing on the fatigue performance of hard turned and ground surfaces is also discussed. Specifically, the surface integrity and fatigue life of the following five distinct surface conditions are examined: hard turned with continuous white layer, hard turned with no white layer, ground, and superfinished hard turned and ground specimens. Surface integrity of the specimens is characterized via surface topography measurement, metallography, residual stress measurements, transmission electron microscopy (TEM), and nano-indentation tests. High cycle tension-tension fatigue tests show that the presence of white layer does not adversely affect fatigue life and that, on average, the hard turned surface performs as well or better than the ground surface. The effect of superfinishing is to exaggerate these differences in performance. The results obtained from this study suggest that the effect of residual stress on fatigue life is more significant than the effect of white layer. For the hard turned surfaces, the fatigue life is found to be directly proportional to both the surface compressive residual stress and the maximum compressive residual stress. Possible explanations for the observed effects are discussed.

  13. Effect of shot peening on surface fatigue life of carburized and hardened AISI 9310 spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Zaretsky, E. V.

    1982-01-01

    Surface fatigue tests were conducted on two groups of AISI 9310 spur gears. Both groups were manufactured with standard ground tooth surfaces, with the second group subjected to an additional shot peening process on the gear tooth flanks. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a gear temperature of 350 K (170 F), a maximum Hertz stress of 1.71 billion N/sq m (248,000 psi), and a speed of 10,000 rpm. The shot peened gears exhibited pitting fatigue lives 1.6 times the life of standard gears without shot peening. Residual stress measurements and analysis indicate that the longer fatigue life is the result of the higher compressive stress produced by the shot peening. The life for the shot peened gear was calculated to be 1.5 times that for the plain gear by using the measured residual stress difference for the standard and shot peened gears. The measured residual stress for the shot peened gears was much higher than that for the standard gears.

  14. Effect of Austenitizing Heat Treatment on the Microstructure and Hardness of Martensitic Stainless Steel AISI 420

    NASA Astrophysics Data System (ADS)

    Barlow, L. D.; Du Toit, M.

    2012-07-01

    The effect of austenitizing on the microstructure and hardness of two martensitic stainless steels was examined with the aim of supplying heat-treatment guidelines to the user that will ensure a martensitic structure with minimal retained austenite, evenly dispersed carbides and a hardness of between 610 and 740 HV (Vickers hardness) after quenching and tempering. The steels examined during the course of this examination conform in composition to medium-carbon AISI 420 martensitic stainless steel, except for the addition of 0.13% vanadium and 0.62% molybdenum to one of the alloys. Steel samples were austenitized at temperatures between 1000 and 1200 °C, followed by oil quenching. The as-quenched microstructures were found to range from almost fully martensitic structures to martensite with up to 35% retained austenite after quenching, with varying amounts of carbides. Optical and scanning electron microscopy was used to characterize the microstructures, and X-ray diffraction was employed to identify the carbide present in the as-quenched structures and to quantify the retained austenite contents. Hardness tests were performed to determine the effect of heat treatment on mechanical properties. As-quenched hardness values ranged from 700 to 270 HV, depending on the amount of retained austenite. Thermodynamic predictions (using the CALPHAD™ model) were employed to explain these microstructures based on the solubility of the carbide particles at various austenitizing temperatures.

  15. Investigation of Low-Cycle Bending Fatigue of AISI 9310 Steel Spur Gears

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Krantz, Timothy L.; Lerch, Bradley A.; Burke, Christopher S.

    2007-01-01

    An investigation of the low-cycle bending fatigue of spur gears made from AISI 9310 gear steel was completed. Tests were conducted using the single-tooth bending method to achieve crack initiation and propagation. Tests were conducted on spur gears in a fatigue test machine using a dedicated gear test fixture. Test loads were applied at the highest point of single tooth contact. Gear bending stresses for a given testing load were calculated using a linear-elastic finite element model. Test data were accumulated from 1/4 cycle to several thousand cycles depending on the test stress level. The relationship of stress and cycles for crack initiation was found to be semi-logarithmic. The relationship of stress and cycles for crack propagation was found to be linear. For the range of loads investigated, the crack propagation phase is related to the level of load being applied. Very high loads have comparable crack initiation and propagation times whereas lower loads can have a much smaller number of cycles for crack propagation cycles as compared to crack initiation.

  16. Effect of two synthetic lubricants on life of AISI 9310 spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Shimski, John

    1991-01-01

    Spur-gear fatigue tests were conducted with two lubricants using a single lot of consumable-electrode vacuum-melted (CVM) AISI 9310 spur gears. The gears were case carburized and hardened to Rockwell C60. The gear pitch diameter was 8.89 cm. The lot of gears was divided into two groups, each of which was tested with a different lubricant. The test lubricants can be classified as synthetic polyol-ester-based lubricants. One lubricant was 30 percent more viscous that the other. Both lubricants have similar pressure viscosity coefficients. Test conditions included a bulk gear temperature of 350 K, a maximum Hertz stress of 1.71 GPa at the pitch line, and a speed of 10,000 rpm. The surface fatigue life of gears tested with one lubricant was approximately 2.4 times that for gears tested with the other lubricant. The lubricant with the 30 percent higher viscosity gave a calculated elastohydrodynamic (EHD) film thickness that was 20 percent higher than the other lubricant. This increased EHD film thickness is the most probable reason for the improvement in surface fatigue life of gears tested with this lubricant over gears tested with the less viscous lubricant.

  17. Investigation of Low-Cycle Bending Fatigue of AISI 9310 Steel Spur Gears

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Krantz, Timothy L.; Lerch, Bradley A.; Burke, Christopher S.

    2007-01-01

    An investigation of the low-cycle bending fatigue of spur gears made from AISI 9310 gear steel was completed. Tests were conducted using the single-tooth bending method to achieve crack initiation and propagation. Tests were conducted on spur gears in a fatigue test machine using a dedicated gear test fixture. Test loads were applied at the highest point of single tooth contact. Gear bending stresses for a given testing load were calculated using a linear-elastic finite element model. Test data were accumulated from 1/4 cycle to several thousand cycles depending on the test stress level. The relationship of stress and cycles for crack initiation was found to be semilogarithmic. The relationship of stress and cycles for crack propagation was found to be linear. For the range of loads investigated, the crack propagation phase is related to the level of load being applied. Very high loads have comparable crack initiation and propagation times whereas lower loads can have a much smaller number of cycles for crack propagation cycles as compared to crack initiation.

  18. Effect of superheat on the solidification structures of AISI 310S austenitic stainless steel

    SciTech Connect

    Ozbayraktar, S.; Koursaris, A.

    1996-04-01

    An experimental study was carried out to investigate the evolution of macrostructure and microstructure in AISI 310S stainless steel during solidification. Experimental findings suggested that the macrostructure a/nd the microstructure of the cast material responded differently to variations in casting temperature. As the casting temperature decreased, the macrostructure was refined, as expected, but the microstructure coarsened. A relationship was established between the proportion of equiaxed zone and superheat as follows: pct equiaxed zone = a + b ln (1/{Delta}T), where a and b are constants. The relationship between grain width and superheat could be expressed by the equation: gw = e(c+d/{Delta}T), where c and d are constants determined by the distance from the edge of the ingot. The relationship between primary arm spacing and superheat could be expressed by the equation: {lambda}{sub 1} = p + q ln (1/{Delta}T), where p and q are constants determined by the distance from the edge of the ingot. The parameter grain width ratio has been introduced to describe the relationship between the shape and the nucleation and growth kinetics of the columnar grains.

  19. Computational Modeling of Microstructural-Evolution in AISI 1005 Steel During Gas Metal Arc Butt Welding

    NASA Astrophysics Data System (ADS)

    Grujicic, M.; Ramaswami, S.; Snipes, J. S.; Yavari, R.; Arakere, A.; Yen, C.-F.; Cheeseman, B. A.

    2013-05-01

    A fully coupled (two-way), transient, thermal-mechanical finite-element procedure is developed to model conventional gas metal arc welding (GMAW) butt-joining process. Two-way thermal-mechanical coupling is achieved by making the mechanical material model of the workpiece and the weld temperature-dependent and by allowing the potential work of plastic deformation resulting from large thermal gradients to be dissipated in the form of heat. To account for the heat losses from the weld into the surroundings, heat transfer effects associated with natural convection and radiation to the environment and thermal-heat conduction to the adjacent workpiece material are considered. The procedure is next combined with the basic physical-metallurgy concepts and principles and applied to a prototypical (plain) low-carbon steel (AISI 1005) to predict the distribution of various crystalline phases within the as-welded material microstructure in different fusion zone and heat-affected zone locations, under given GMAW-process parameters. The results obtained are compared with available open-literature experimental data to provide validation/verification for the proposed GMAW modeling effort.

  20. White Layer Formation Due to Phase Transformation to Orthogonal machine of AISI 1045 Annealed Steel

    SciTech Connect

    Han, Sangil; Melkote, Shreyes N; Haluska, Dr. Michael S; Watkins, Thomas R

    2008-01-01

    It is commonly believed that the white layer formed during machining of steels is caused primarily by a thermally induced phase transformation resulting from rapid heating and quenching. As a result, it is often assumed that if the temperature at the tool flank-workpiece interface exceeds the nominal phase transformation temperature for the steel, a white layer forms. However, no attempt has been made to actually measure the temperatures produced at the tool flank-workpiece interface and correlate it with microstructural evidence of phase transformation. This paper aims to address these limitations through suitably designed experiments and analysis. Orthogonal machining tests were performed on AISI 1045 annealed steel at different cutting speeds and tool flank wear. During machining, temperature measurements at the tool flank-workpiece interface were made using an exposed thermocouple technique. Metallographic studies of the machined sub-surface and X-ray diffraction (XRD) measurements were performed to determine the presence and depth of white layer, and the presence of the retained austenite phase in the machined surface layer, respectively. Analysis of the data shows that the white layer can form due to phase transformation at temperatures below the nominal austenitization temperature of the steel. Possible causes of this result are presented.

  1. Linking anisotropy with Fe3C distribution in AISI 1045 steel

    NASA Astrophysics Data System (ADS)

    Shen, Ke-chang; Li, Gui-hua; Sun, Yi-min; Wang, Yong-gang; Li, Ying-jie; Cao, Guang-hui; Wang, Wei-min

    2015-12-01

    The anisotropy of the microstructure, thermal expansion behavior, corrosion resistance and magnetic properties of AISI 1045 steel was investigated. The distribution of Fe3C lamellae in the investigation plane parallel to the radial directions of molds was observed to differ from that in the investigation plane perpendicular to the radial directions by transmission electron microscopy. The lattice constants a 0 of α-Fe deduced from the XRD patterns of samples prepared using a sand (S)-mold and cut parallel to the radial direction of the mold (S//) and using a metal (M)-mold and cut parallel to the radial direction (M//), the corrosion resistance measured using an electrochemical workstation, and the magnetic permeability obtained by vibrating sample magnetometry also indicated the existence of anisotropy in the tested samples. The anisotropic change of corrosion potential ( E corr), pitting potential ( E pit) and magnetic permeability ( µ) of the samples was observed to depend on the orientation factor F 200 of α-Fe in the measured samples, which is controlled by the distribution of Fe3C lamellae in the eutectoid structure.

  2. Investigations on Surface Milling of Hardened AISI 4140 Steel with Pulse Jet MQL Applicator

    NASA Astrophysics Data System (ADS)

    Bashir, Mahmood Al; Mia, Mozammel; Dhar, Nikhil Ranjan

    2016-06-01

    In this article, an experimental investigation was performed in milling hardened AISI 4140 steel of hardness 40 HRC. The machining was performed in both dry and minimal quantity lubricant (MQL) conditions, as part of neat machining, to make a strong comparison of the undertaken machining environments. The MQL was impinged int the form of pulse jet, by using the specially developed pulse-jet-attachment, to ensure that the cutting fluid can be applied in different timed pulses and quantities at critical zones. The tool wear, cutting force and surface roughness were taken as the quality responses while cutting speed, table feed rate and flow rate of the pulse were considered as influential factors. The depth of cut was kept constant at 1.50 mm because of its less significant effects and the straight oil was adopted as cutting fluid in pulse-jet-MQL. The effects of different factors, on the quality responses, are analyzed using ANOVA. It is observed that MQL applicator system exhibits overall better performance when compared to dry milling by reducing surface roughness, cutting force and prolonging tool life but a flow rate of 150 ml/h has tremendous effects on the responses. This investigation and afterward results are expected to aid the industrial practitioner and researcher to adopt the pulse-MQL in high speed milling to prolong tool life, reduce tool wear, diminish cutting force generation and promote better surface finish.

  3. Fe-Based Amorphous Coatings on AISI 4130 Structural Steel for Corrosion Resistance

    NASA Astrophysics Data System (ADS)

    Katakam, Shravana; Santhanakrishnan, S.; Dahotre, Narendra B.

    2012-06-01

    The current study focuses on synthesizing a novel functional coating for corrosion resistance applications, via laser surface alloying. The iron-based (Fe48Cr15Mo14Y2C15B) amorphous precursor powder is used for laser surface alloying on AISI 4130 steel substrate, with a continuous wave ytterbium Nd-YAG fiber laser. The corrosion resistance of the coatings is evaluated for different processing conditions. The microstructural evolution and the response of the microstructure to the corrosive environment is studied using x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Microstructural studies indicate the presence of face-centered cubic Fe-based dendrites intermixed within an amorphous matrix along with fine crystalline precipitates. The corrosion resistance of the coatings decrease with an increase in laser energy density, which is attributed to the precipitation and growth of chromium carbide. The enhanced corrosion resistance of the coatings processed with low energy density is attributed to the self-healing mechanism of this amorphous system.

  4. The Meta-Lax method of stress reduction in welds. [ASTM A36; AISI 4140

    SciTech Connect

    Smith, S.M.

    1992-07-31

    This study is the second phase of ongoing research into the mechanics and feasibility of using the Meta-Lax method of vibratory stress relief in place of thermal methods of stress relief. The first phase of this research revealed results that were similar to, and even superior to those achieved using thermal methods. The testing here was designed to eliminate the effects of interbead tempering by utilizing single pass bead-on-plate welds only. A metallurgical explanation for the success of the Meta-Lax method was not found. No significant structure or chemical changes were noted when used with ASTM A36 or AISI 4140 materials, and the phenomena noted in phase I was apparently due to interbead tempering. The theory of accelerated aging has been proposed and studies exist which observed dislocation motion as a result of vibratory treatment. It is evident that the vibratory stress relief system does not impart sufficient energy to bring about the magnitude of change seen with thermal methods. however the physical improvement is a reality, and vibratory methods should be evaluated further.

  5. Nano- and Macro-wear of Bio-carbo-nitrided AISI 8620 Steel Surfaces

    NASA Astrophysics Data System (ADS)

    Arthur, Emmanuel Kwesi; Ampaw, Edward; Zebaze Kana, M. G.; Adetunji, A. R.; Olusunle, S. O. O.; Adewoye, O. O.; Soboyejo, W. O.

    2015-12-01

    This paper presents the results of an experimental study of nano- and macro-scale wear in a carbo-nitrided AISI 8620 steel. Carbo-nitriding is carried out using a novel method that involves the use of dried, cyanide-containing cassava leaves, as sources of carbon and nitrogen. These are used in a pack cementation that is used to diffuse carbon and nitrogen into case layers at intermediate temperatures [673.15 K, 723.15 K, 773.15 K, and 823.15 K (400 °C, 450 °C, 500 °C, and 550 °C)]. Nano- and macro-scale wear properties are studied in the case-hardened surfaces, using a combination of nano-scratch and pin-on-disk experiments. The measured wear volumes (at both nano- and macro-length scales) are shown to increase with decreasing pack cyaniding temperature. The nano- and macro-wear resistances are also shown to be enhanced by the in situ diffusion of carbon and nitrogen from cyanide-containing bio-processed waste. The underlying wear mechanisms are also elucidated via atomic force microscopy and scanning electron microscopy observations of the wear tracks. The implications of the results are discussed for the design of hardened carbo-nitrided steel surfaces with improved wear resistance.

  6. Thermodynamic modeling and kinetics simulation of precipitate phases in AISI 316 stainless steels

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Busby, J. T.

    2014-05-01

    This work aims at utilizing modern computational microstructural modeling tools to accelerate the understanding of phase stability in austenitic steels under extended thermal aging. Using the CALPHAD approach, a thermodynamic database OCTANT (ORNL Computational Thermodynamics for Applied Nuclear Technology), including elements of Fe, C, Cr, Ni, Mn, Mo, Si, and Ti, has been developed with a focus on reliable thermodynamic modeling of precipitate phases in AISI 316 austenitic stainless steels. The thermodynamic database was validated by comparing the calculated results with experimental data from commercial 316 austenitic steels. The developed computational thermodynamics was then coupled with precipitation kinetics simulation to understand the temporal evolution of precipitates in austenitic steels under long-term thermal aging (up to 600,000 h) at a temperature regime from 300 to 900 °C. This study discusses the effect of dislocation density and difusion coefficients on the precipitation kinetics at low temperatures, which shed a light on investigating the phase stability and transformation in austenitic steels used in light water reactors.

  7. Prediction of Cutting Forces Using ANNs Approach in Hard Turning of AISI 52100 steel

    SciTech Connect

    Makhfi, Souad; Habak, Malek; Velasco, Raphael; Haddouche, Kamel; Vantomme, Pascal

    2011-05-04

    In this study, artificial neural networks (ANNs) was used to predict cutting forces in the case of machining the hard turning of AISI 52100 bearing steel using cBN cutting tool. Cutting forces evolution is considered as the key factors which affect machining. Predicting cutting forces evolution allows optimizing machining by an adaptation of cutting conditions. In this context, it seems interesting to study the contribution that could have artificial neural networks (ANNs) on the machining forces prediction in both numerical and experiment studies. Feed-forward multi-layer neural networks trained by the error back-propagation (BP) algorithm are used. Levenberg-Marquardt (LM) optimization algorithm was used for finding out weights. The training of the network is carried out with experimental machining data.The input dataset used are cutting speed, feed rate, cutting depth and hardness of the material. The output dataset used are cutting forces (Ft-cutting force, Fa- feed force and Fr- radial force).Results of the neural networks approach, in comparison with experimental data are discussed in last part of this paper.

  8. Some Temperature Effects on AISI-304 Nitriding in an Inductively Coupled RF Plasma

    SciTech Connect

    Valencia-Alvarado, R.; Barocio, S. R.; Mercado-Cabrera, A.; Pena-Eguiluz, R.; Munoz-Castro, A. E.; Piedad-Beneitez, A. de la; Rosa-Vazquez, J. de la; Lopez-Callejas, R.; Godoy-Cabrera, O. G.

    2006-12-04

    Some recent results obtained from nitriding AISI 304 stainless steel samples, 1.2 cm in diameter and 0.5 cm thick are reported here in the case of an 85% hydrogen and 15% nitrogen mixture work gas. The process was carried out from 300 to 400 W for (13.56 MHz) inductively coupled plasma within a 60 cm long pyrex glass tube 3.5 cm in diameter where the samples were biased up to -300 V with respect to earth. The resulting hardness appears to be a function of the substrate temperature which varied from 200 deg. C at a 0 V bias to 550 deg. C at -300 V. The plasma density at 400 W reached 3x1010 cm-3 with a 4 eV electron temperature. Prior to nitriding, all the samples were polished with 0.05 {mu}m diamond paste, leading to a 30 nm average roughness (Ra). After nitriding at -300 V, the Ra rose until {approx}400 nm while hardness values of 1500 HV under 300 g loads were measured. X ray diffraction indicates that the extended phase amplitude ({gamma}N), Fe and Cr nitride depends on the substrate temperature.

  9. Microstructure and oxidation behavior of high strength steel AISI 410 implanted with nitrogen ion

    NASA Astrophysics Data System (ADS)

    Bandriyana, Ismoyo, Agus Hadi; Sujitno, Tjipto; Dimyati, A.

    2016-04-01

    Surface treatment by implantation with nitrogen-ion was performed on the commercial feritic high strength steel AISI 410 which is termed for high temperature applications. The aim of this research was focused on the surface modification to improve its high temperature oxidation property in the early stages. Ion implantation was carried out at acceleration energy of 100 KeV and ion current 10 mA for 30, 60 and 90 minutes. The samples were subjected to the high temperature oxidation test by means of thermogravimetry in a magnetic suspension balance (MSB) at 500 °C for 5 hours. The scanning electron microscopy (SEM), X-ray diffraction spectrometry (XRD) and Vickers Hardness measurement were used for sample characterization. The formation of ferro-nitride phase after implantation did not occur, however a thin layer considered to contain nitrogen interstitials was detected. The oxidation of both samples before and after implantation followed parabolic kinetics indicating inward growth of oxide scale characteristically due to diffusion of oxygen anions towards matrix surface. After oxidation test relativelly stable oxide scales were observed. Oxidation rates decreased proportionally with the increasing of implantation time due to the formation of oxide layer which is considered to be effectiv inhibitor for the oxygen diffusion.

  10. Effect of welding parameters on the heat-affected zone of AISI409 ferritic stainless steel

    NASA Astrophysics Data System (ADS)

    Ranjbarnodeh, Eslam; Hanke, Stefanie; Weiss, Sabine; Fischer, Alfons

    2012-10-01

    One of the main problems during the welding of ferritic stainless steels is severe grain growth within the heat-affected zone (HAZ). In the present study, the microstructural characteristics of tungsten inert gas (TIG) welded AISI409 ferritic stainless steel were investigated by electron backscattered diffraction (EBSD), and the effects of welding parameters on the grain size, local misorientation, and low-angle grain boundaries were studied. A 3-D finite element model (FEM) was developed to predict the effects of welding parameters on the holding time of the HAZ above the critical temperature of grain growth. It is found that the base metal is not fully recrystallized. During the welding, complete recrystallization is followed by severe grain growth. A decrease in the number of low-angle grain boundaries is observed within the HAZ. FEM results show that the final state of residual strains is caused by competition between welding plastic strains and their release by recrystallization. Still, the decisive factor for grain growth is heat input.

  11. Surface characterisation and corrosion behaviour of SiC-coated AISI 321 stainless steel

    NASA Astrophysics Data System (ADS)

    Misaelides, P.; Noli, F.; Riviere, J. P.; Delafond, J.

    1997-07-01

    The influence of SiC-coatings on the corrosion properties of AISI 321 austenitic stainless steel (Fe/Cr18/Ni8/Ti) in 1N H 2SO 4 was studied. SiC-coatings of various thicknesses (100-800 nm) were prepared at room temperature (RT) or at temperatures up to 750°C by ion beam sputtering of a SiC-target. The growing films could be continuously bombarded with a 160 keV Ar + ion beam and the role of this Dynamic Ion Mixing (DIM) on both the structure and corrosion resistance was investigated. The chemical composition of the coatings was determined by Rutherford Backscattering (RBS) using 1.8 MeV α-particles and by Nuclear Reaction Analysis (NRA). Transmission Electron Microscopy (TEM) observations were also performed for the determination of the microstructural state of the samples. The characterisation shows, that for all the deposition temperatures the DIM-treatment promotes the crystallisation of the β-SiC phase. It was also found, that the corrosion resistance of the stainless steel is considerably improved when the coatings are deposited by DIM regardless of the deposition temperature. The possible mechanisms are discussed and it is suggested that the interface mixing along with the coating densification effect are responsible for the improvement of the corrosion resistance.

  12. Fabrication of spectrally selective solar surfaces by the thermal treatment of austenitic stainless steel aisi 321

    SciTech Connect

    Sharma, V.C.

    1981-05-19

    The spectrally selective solar surfaces have been produced after heating the austenitic stainless steel aisi 321 at a firing temperature of 843* K. And for firing times ranging from 10 to 20 minutes. The heating was carried out in a constant temperature oven under normal atmospheric conditions. The optimum values of solar absorptance alpha S and near-normal emittance epsilon S were found to be alpha S 0.92+0.02, epsilon S 0.22 + or - 0.02 respectively. The corresponding values for the unheated steel were 0.50 + or - 0.02 and 0.22 + or - 0.22. Severe temperature treatments like quenching in liquid nitrogen at 77* K. Produced no adverse visible affect on the quality of the selective surfaces. It shows that the thermal coatings so produced are very tough and durable. The value of solar absorptance and near-normal thermal emittance remained unchanged after quenching in liquod nitrogen. The thermal coatings so produced not only offer a technical advantage but also economic advantage over any of the existing techniques for the manufacture of stainless steel solar panels.

  13. Effect of lubricant extreme-pressure additives on surface fatigue life of AISI 9310 spur gears

    NASA Technical Reports Server (NTRS)

    Scibbe, H. W.; Townsend, D. P.; Aron, P. R.

    1984-01-01

    Surface fatigue tests were conducted with AISI 9310 spur gears using a formulated synthetic tetraester oil (conforming to MIL-L-23699 specifications) as the lubricant containing either sulfur or phosphorus as the EP additive. Four groups of gears were tested. One group of gears tested without an additive in the lubricant acted as the reference oil. In the other three groups either a 0.1 wt % sulfur or phosphorus additive was added to the tetraester oil to enhance gear surface fatigue life. Test conditions included a gear temperature of 334 K (160 F), a maximum Hertz stress of 1.71 GPa (248 000 psi), and a speed of 10,000 rpm. The gears tested with a 0.1 wt % phosphorus additive showed pitting fatigue life 2.6 times the life of gears tested with the reference tetraester based oil. Although fatigue lives of two groups of gears tested with the sulfur additive in the oil showed improvement over the control group gear life, the results, unlike those obtained with the phosphorus oil, were not considered to be statistically significant.

  14. Surface modification of AISI H13 tool steel by laser cladding with NiTi powder

    NASA Astrophysics Data System (ADS)

    Norhafzan, B.; Aqida, S. N.; Chikarakara, E.; Brabazon, D.

    2016-04-01

    This paper presents laser cladding of NiTi powder on AISI H13 tool steel surface for surface properties enhancement. The cladding process was conducted using Rofin DC-015 diffusion-cooled CO2 laser system with wavelength of 10.6 µm. NiTi powder was pre-placed on H13 tool steel surface. The laser beam was focused with a spot size of 90 µm on the sample surface. Laser parameters were set to 1515 and 1138 W peak power, 18 and 24 % duty cycle and 2300-3500 Hz laser pulse repetition frequency. Hardness properties of the modified layer were characterized by Wilson Hardness tester. Metallographic study and chemical composition were conducted using field emission scanning electron microscope and energy-dispersive X-ray spectrometer (EDXS) analysis. Results showed that hardness of NiTi clad layer increased three times that of the substrate material. The EDXS analysis detected NiTi phase presence in the modified layer up to 9.8 wt%. The metallographic study shows high metallurgical bonding between substrate and modified layer. These findings are significant to both increased hardness and erosion resistance of high-wear-resistant components and elongating their lifetime.

  15. Influence of steel type on the propensity for tribochemical wear in boundary lubrication with a wind turbine gear oil

    SciTech Connect

    Evans, Ryan D.; Doll, Gary L.; Hager, C H; Howe, Jane Y

    2010-01-01

    Tribochemical wear may occur at the interface between a surface and a lubricant as a result of chemical and mechanical interactions in a tribological contact. Understanding the onset of tribochemical wear damage on component surfaces requires the use of high resolution techniques such as transmission electron microscopy (TEM). In this study, two steel types, case carburized AISI 3310 and through-hardened AISI 52100, were wear tested using a ball-on-disk rolling/sliding contact tribometer in fully formulated commercial wind turbine gearbox oil under boundary lubrication conditions with 10% slip. With the exception of steel type, all other test conditions were held constant. Conventional tribofilm analysis in the wear tracks was performed using X-ray photoelectron spectroscopy, and no significant composition differences were detected in the tribofilms for the different steel disk types. However, TEM analysis revealed significant tribochemical wear differences between the two steel types at multiple length scales, from the near-surface material microstructure (depth < 500 nm) to the tribofilm nanostructure. Nanometer-scale interfacial cracking and surface particle detachment was observed for the AISI 52100 case, whereas the tribofilm/substrate interface was abrupt and undamaged for the AISI 3310 case. Differences in tribofilm structure, including the location and orientation of MoS{sub 2} single sheet inclusions, were observed as a function of steel type as well. It is suggested that the tribochemical wear modes observed in these experiments may be origins of macroscopic surface-initiated damage such as micropitting in bearings and gears.

  16. Resistance to Corrosion of Zirconia Coatings Deposited by Spray Pyrolysis in Nitrided Steel

    NASA Astrophysics Data System (ADS)

    Cubillos, G. I.; Olaya, J. J.; Bethencourt, M.; Cifredo, G.; Blanco, G.

    2013-10-01

    Coatings of zirconium oxide were deposited onto three types of stainless steel, AISI 316L, 2205, and tool steel AISI D2, using the ultrasonic spray pyrolysis method. The effect of the flux ratio on the process and its influence on the structure and morphology of the coatings were investigated. The coatings obtained, 600 nm thick, were characterized using x-ray diffraction, scanning electron microscopy, confocal microscopy, and atomic force microscopy. The resistance to corrosion of the coatings deposited over steel (not nitrided) and stainless steel nitrided (for 2 h at 823 K) in an ammonia atmosphere was evaluated. The zirconia coating enhances the stainless steel's resistance to corrosion, with the greatest increase in corrosion resistance being observed for tool steel. When the deposition is performed on previously nitrided stainless steel, the morphology of the surface improves and the coating is more homogeneous, which leads to an improved corrosion resistance.

  17. Analyses of oxide films grown on AISI 304L stainless steel and Incoloy 800HT exposed to supercritical water environment

    NASA Astrophysics Data System (ADS)

    Fulger, Manuela; Mihalache, Maria; Ohai, Dumitru; Fulger, Stefan; Valeca, Serban Constantin

    2011-08-01

    Supercritical water (SCW) is being considered as a cooling medium for the next generation nuclear reactors because it provides high thermal efficiency and plant simplification. However, materials corrosion has been identified as a critical problem due to the oxidative nature of supercritical water. Thus, for safety using of these nuclear reactor systems a systematic study of candidate materials corrosion is needed. As in other high temperature environments, corrosion in SCW occurs by the growth of an oxide layer on the materials surface. The current work aims to evaluate oxidation behavior of AISI 304L SS and Incoloy 800HT in water at supercritical temperatures in the range 723-873 K under a pressure of 25 MPa for up to 1680 h. After exposure to deaerated supercritical water, the samples were investigated using gravimetry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS). Oxide films grown on these materials have a layered structure with an outer layer consisting of a mixture of iron oxide/iron-nickel spinel oxides and an inner layer consisting of chromium oxide in the case of Incoloy 800HT and nickel-chromium spinel oxide in the case of AISI 304L SS. The mass gains for Incoloy 800HT at all temperatures were small, while comparatively with AISI 304L SS which exhibited higher oxidation rates. In the same time the results obtained by EIS indicate the best corrosion resistance of oxides grown on Incoloy 800HT surface.

  18. Machining Performance and Surface Integrity of AISI D2 Die Steel Machined Using Electrical Discharge Surface Grinding Process

    NASA Astrophysics Data System (ADS)

    Choudhary, Rajesh; Kumar, Harmesh; Singh, Shankar

    2013-12-01

    The aim of this study is to establish optimum machining conditions for EDSG of AISI D2 die steel through an experimental investigation using Taguchi Methodology. To achieve combined grinding and electrical discharge machining, metal matrix composite electrodes (Cu-SiCp) were processed through powder metallurgy route. A rotary spindle attachment was developed to perform the EDSG experimental runs on EDM machine. Relationships were developed between various input parameters such as peak current, speed, pulse-on time, pulse-off time, abrasive particle size, and abrasive particle concentration, and output characteristics such as material removal rate and surface roughness. The optimized parameters were further validated by conducting confirmation experiments.

  19. Mechanical behavior of AISI 304SS determined by miniature test methods after neutron irradiation to 28 dpa

    SciTech Connect

    Ellen M. Rabenberg; Brian J. Jaques; Bulent H. Sencer; Frank A. Garner; Paula D. Freyer; Taira Okita; Darryl P. Butt

    2014-05-01

    The mechanical properties of AISI 304 stainless steel irradiated for over a decade in the Experimental Breeder Reactor (EBR-II) were measured using miniature mechanical testing methods. The shear punch method was used to evaluate the shear strengths of the neutron-irradiated steel and a correlation factor was empirically determined to predict its tensile strength. The strength of the stainless steel slightly decreased with increasing irradiation temperature, and significantly increased with increasing dose until it saturated above approximately 5 dpa. Ferromagnetic measurements were used to observe and deduce the effects of the stress-induced austenite to martensite transformation as a result of shear punch testing.

  20. Formation of amorphous Ti alloy layers by excimer laser mixing of Ti on AISI 304 stainless-steel surfaces

    NASA Astrophysics Data System (ADS)

    Jervis, T. R.; Nastasi, M.; Zocco, T. G.; Martin, J. A.

    1988-07-01

    We used excimer laser radiation at 308 nm to mix thin layers of Ti into AISI 304 stainless steel. Different numbers of shots at a fluence about twice the threshold for melting varied the amount of mixing. When mixing is sufficiently complete, an amorphous surface layer is formed with Ti substituting for Fe on a one-to-one basis in the alloy. The laser mixing process, unlike Ti ion implantation, does not result in high incorporation of C in the processed layer, although some C from surface and interface contamination is incorporated into the surface layer.

  1. Investigation of AISI 441 Ferritic Stainless Steel and Development of Spinel Coatings for SOFC Interconnect Applications

    SciTech Connect

    Yang, Zhenguo; Xia, Guanguang; Wang, Chong M.; Nie, Zimin; Templeton, Joshua D.; Singh, Prabhakar; Stevenson, Jeffry W.

    2008-05-30

    As part of an effort to develop cost-effective ferritic stainless steel-based interconnects for solid oxide fuel cell (SOFC) stacks, both bare and spinel coated AISI 441 were studied in terms of metallurgical characteristics, oxidation behavior, and electrical performance. The conventional melt metallurgy used for the bulk alloy fabrication leads to significant processing cost reduction and the alloy chemistry with the presence of minor alloying additions of Nb and Ti facilitate the strengthening by precipitation and formation of Laves phase both inside grains and along grain boundaries during exposure in the intermediate SOFC operating temperature range. The Laves phase formed along the grain boundaries also ties up Si and prevents the formation of an insulating silica layer at the scale/metal interface during prolonged exposure. The substantial increase in ASR during long term oxidation due to oxide scale growth suggested the need for a conductive protection layer, which could also minimize Cr evaporation. In particular, Mn1.5Co1.5O4 based surface coatings on planar coupons drastically improved the electrical performance of the 441, yielding stable ASR values at 800ºC for over 5,000 hours. Ce-modified spinel coatings retained the advantages of the unmodified spinel coatings, and also appeared to alter the scale growth behavior beneath the coating, leading to a more adherent scale. The spinel protection layers appeared also to improve the surface stability of 441 against the anomalous oxidation that has been observed for ferritic stainless steels exposed to dual atmosphere conditions similar to SOFC interconnect environments. Hence, it is anticipated that, compared to unmodified spinel coatings, the Ce-modified coatings may lead to superior structural stability and electrical performance.

  2. Morphology, topography, and hardness of diffusion bonded sialon to AISI 420 at different bonding time

    NASA Astrophysics Data System (ADS)

    Ibrahim, Nor Nurulhuda Md.; Hussain, Patthi; Awang, Mokhtar

    2015-07-01

    Sialon and AISI 420 martensitic stainless steel were diffusion bonded in order to study the effect of bonding time on reaction layer's growth. Joining of these materials was conducted at 1200°C under a uniaxial pressure of 17 MPa in a vacuum ranging from 5.0 to 8.0×10-6 Torr with bonding time varied for 0.5, 2, and 3 h. Thicker reaction layer was formed in longer bonded sample since the elements from sialon could diffuse further into the steel. Sialon retained its microstructure but it was affected at the initial contact with the steel to form the new interface layer. Diffusion layer grew toward the steel and it was segregated with the parent steel as a result of the difference in properties between these regions. The segregation formed a stream-like structure and its depth decreased when the bonding time was increased. The microstructure of the steel transformed into large grain size with precipitates. Prolonging the bonding time produced more precipitates in the steel and reduced the steel thickness as well. Interdiffusions of elements occurred between the joined materials and the concentrations were decreasing toward the steel and vice versa. Silicon easily diffused into the steel because it possessed lower ionization potential compared to nitrogen. Formation of silicide and other compounds such as carbides were detected in the interface layer and steel grain boundary, respectively. These compounds were harmful due to silicide brittleness and precipitation of carbides in the grain boundary might cause intergranular corrosion cracking. Sialon retained its hardness but it dropped very low at the interface layer. The absence of crack at the joint in all samples could be contributed from the ductility characteristic of the reaction layer which compensated the residual stress that was formed upon the cooling process.

  3. Fatigue life improvements of the AISI 304 stainless steel ground surfaces by wire brushing

    NASA Astrophysics Data System (ADS)

    Ben Fredj, Nabil; Ben Nasr, Mohamed; Ben Rhouma, Amir; Sidhom, Habib; Braham, Chedly

    2004-10-01

    The surface and subsurface integrity of metallic ground components is usually characterized by an induced tensile residual stress, which has a detrimental effect on the fatigue life of these components. In particular, it tends to accelerate the initiation and growth of the fatigue cracks. In this investigation, to deliberately generate compressive residual stresses into the ground surfaces of the AISI 304 stainless steel (SS), wire brushing was applied. It was found that under the experimental conditions selected in this investigation, while the surface roughness was slightly improved by the brushing process, the surface residual stress shifted from a tensile stress (σ‖=+450 MPa) to a compressive stress (σ‖=-435 MPa). On the other hand, the work-hardened deformation layer was almost two times deeper after wire brushing. Concerning the fatigue life, an improvement of 26% in terms of endurance limit at 2×106 cycles was realized. Scanning electron microscope (SEM) observations of the fatigue fracture location and size were carried out to explain the fatigue life improvement. It was found that the enhancement of the fatigue strength could be correlated with the distribution and location of the fatigue fracture nucleation sites. Concerning the ground surfaces, it was seen that the fatigue cracks initiated at the bottom of the grinding grooves and were particularly long (150-200 µm). However, the fatigue cracks at the brushed surfaces were shorter (20-40 µm) and appeared to initiate sideways to the plowed material caused by the wire brushing. The results of the wire-brushed surface characterization have shown that significant advantages can be realized regarding surface integrity by the application of this low-cost process compared to shot peening.

  4. Swelling and creep observed in AISI 304 fuel pin cladding from three MOX fuel assemblies irradiated in EBR-II

    NASA Astrophysics Data System (ADS)

    Garner, F. A.; Makenas, B. J.; Chastain, S. A.

    2011-06-01

    Three 37-pin MOX-fueled experimental subassemblies were irradiated in EBR-II with fuel pin cladding constructed from annealed AISI 304 stainless steel. Analysis of the swelling and irradiation creep of the cladding showed that the terminal swelling rate of AISI 304 stainless steel appears to be ˜1%/dpa and that swelling is very reproducible for identical irradiation conditions. The swelling at a given neutron fluence is rather sensitive to both irradiation temperature and especially to the neutron flux, however, with the primary influence residing in the transient regime. As the neutron flux increases the duration of the transient regime is increased in agreement with other recent studies. The duration of the transient regime is also decreased by increasing irradiation temperature. In these assemblies swelling reached high levels rather quickly, reducing the opportunity for fuel pin cladding interaction and thereby reducing the contribution of irradiation creep to the total deformation. It also appears that in this swelling-before-creep scenario that the well-known "creep disappearance" phenomenon was operating strongly.

  5. Influence of Surface Preparation on the Kinetics of Controlled Gas-Nitrided AISI H13 Steels Used in Extrusion Dies

    NASA Astrophysics Data System (ADS)

    Akhtar, S. S.; Arif, A. F. M.; Yilbas, B. S.; Sheikh, A. K.

    2010-04-01

    In the aluminum extrusion practice, gas nitriding represents an important factor in enhancing the service life of AISI H13 steel dies. It is observed that if the die-bearing surface is not adequately prepared before nitriding, a nonuniform and shallow nitrided layer develops with reduced hardening effect. The focus of this paper is to investigate the influence of different surface conditions in terms of roughness on the kinetics of nitrided layer developed during gas-nitriding process under controlled nitriding potential. Four samples made of AISI H13 steel properly heat treated (quenched and tempered) were considered: without surface preparation, ground, polished, and lapped. All the samples were gas nitrided under the same conditions and examined after being nitrided. The nitrided layers were characterized using different techniques including optical microscopy, scanning electron microscopy, x-ray diffraction analysis, energy dispersive spectrometry mapping, and microhardness analysis. It was found that the surface preparation prior to nitriding significantly enhanced the nitriding kinetics, which in turn resulted in even and deep nitrided case depth. This provided high load-bearing capacity due to increased and deep hardening effect as compared to unprepared sample. A thinner and uniform compound layer with well-resolved phases was achieved in comparison with unprepared sample.

  6. Co/LaCrO 3 composite coatings for AISI 430 stainless steel solid oxide fuel cell interconnects

    NASA Astrophysics Data System (ADS)

    Shaigan, Nima; Ivey, Douglas G.; Chen, Weixing

    Rapidly decreasing electronic conductivity, chromium volatility and poisoning of the cathode material are the major problems associated with inevitable growth of chromia on ferritic stainless steel interconnects of solid oxide fuel cells (SOFC). This work evaluates the performance of a novel, electrodeposited composite Co/LaCrO 3 coating for AISI 430 stainless steel. The oxidation behaviour of the Co/LaCrO 3-coated AISI 430 substrates is studied in terms of scale microstructure and growth kinetics. Area-specific resistance (ASR) of the coated substrates has also been tested. The results showed that the Co/LaCrO 3 coating forms a triple-layer scale consisting of a chromia-rich subscale, a Co-Fe spinel mid-layer and a Co 3O 4 spinel top layer at 800 °C in air. This scale is protective, acts as an effective barrier against chromium migration into the outer oxide layer and exhibits a low, stable ASR of ∼0.02 Ω cm 2 after 900 h at 800 °C in air.

  7. Tribological properties of CrN coatings deposited by nitro-chromizing treatment on AISI D2 steel

    SciTech Connect

    Durmaz, M. Abakay, E.; Sen, U.; Sen, S.; Kilinc, B.

    2015-03-30

    In this work, the wear test of uncoated and chromium nitride coated AISI D2 cold work tool steel against alumina ball realized at 0.1 m/s sliding speeds and under the loads of 2.5N, 5N and 10N. Steel samples were nitrided at 575°C for 8 h in the first step of the coating process, and then chromium nitride coating was performed thermo-reactive deposition technique (TRD) in a powder mixture consisting of ferro-chromium, ammonium chloride and alumina at 1000°C for 2 h. Nitro-chromized samples were characterized by X-Ray diffraction analysis (XRD), scanning electron microscopy (SEM), micro-hardness and ball on disk wear tests. The coating layer formed on the AISI D2 steel was compact and homogeneous. X-ray studies showed that the phase formed in the coated layer is Cr{sub 2}N. The depth of the layer was 8.15 µm. The average hardness of the layer was 2160±15 HV{sub 0.025}. For uncoated and chromium nitride materials, wear rate increased with increasing load. The results of friction coefficient and wear rate of the tested materials showed that the CrN coating presents the lowest results.

  8. High temperature oxidation behavior of austenitic stainless steel AISI 304 in steam of nanofluids contain nanoparticle ZrO2

    SciTech Connect

    Prajitno, Djoko Hadi Syarif, Dani Gustaman

    2014-03-24

    The objective of this study is to evaluate high temperature oxidation behavior of austenitic stainless steel SS 304 in steam of nanofluids contain nanoparticle ZrO{sub 2}. The oxidation was performed at high temperatures ranging from 600 to 800°C. The oxidation time was 60 minutes. After oxidation the surface of the samples was analyzed by different methods including, optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). X-ray diffraction examination show that the oxide scale formed during oxidation of stainless steel AISI 304 alloys is dominated by iron oxide, Fe{sub 2}O{sub 3}. Minor element such as Cr{sub 2}O{sub 3} is also appeared in the diffraction pattern. Characterization by optical microscope showed that cross section microstructure of stainless steel changed after oxidized with the oxide scale on the surface stainless steels. SEM and x-ray diffraction examination show that the oxide of ZrO{sub 2} appeared on the surface of stainless steel. Kinetic rate of oxidation of austenite stainless steel AISI 304 showed that increasing oxidation temperature and time will increase oxidation rate.

  9. Wear behavior of the surface alloyed AISI 1020 steel with Fe-Nb-B by TIG welding technique

    SciTech Connect

    Kilinc, B. Durmaz, M.; Abakay, E.; Sen, U.; Sen, S.

    2015-03-30

    Weld overlay coatings also known as hardfacing is a method which involves melting of the alloys and solidification for applied coatings. Recently hardfacing by welding has become a commonly used technique for improvement of material performance in extreme (high temperature, impact/abrasion, erosion, etc.) conditions.In the present study, the coatings were produced from a mixture of ferrous niobium, ferrous boron and iron powders in the ranges of -45µm particle size with different ratio. Fe{sub 12}Nb{sub 5}B{sub 3} and Fe{sub 2}NbBalloys were coated on the AISI 1020 steel surface by TIG welding. The phases formed in the coated layer are Fe{sub 2}B, NbB{sub 2}, NbFeB and Fe0,2 Nb{sub 0,8} phases. The hardness of the presence phases are changing between 1689±85 HV{sub 0.01}, and 181±7 HV{sub 0.1}. Microstructural examinations were realized by optical and scanning electron microscopy. The wear and friction behaviors of Fe{sub 12}Nb{sub 5}B{sub 3} and Fe2NbB realized on the AISI 1020 steel were investigated by the technique of TIG welding by using ball-on-disk arrangement against alumina ball.

  10. Welding procedure specification. Supplement 1. Records of procedure qualification tests. Gas tungsten arc welding of AISI 41XX steels. [4130 and 4142

    SciTech Connect

    Wodtke, C.H.; Frizzell, D.R.

    1986-06-01

    Procedure WPS-126 is qualified under Section IX of the ASME Boiler and Pressure Vessel Code for gas tungsten arc welding of AISI 4130 and 4142 steel (ASTM A519) (P-No: None), 0.438-inch wall pipe; filler metal is AMS 6457, Class 4130 MC (F-, A-No: None).

  11. Dynamic recrystallization in friction surfaced austenitic stainless steel coatings

    SciTech Connect

    Puli, Ramesh Janaki Ram, G.D.

    2012-12-15

    Friction surfacing involves complex thermo-mechanical phenomena. In this study, the nature of dynamic recrystallization in friction surfaced austenitic stainless steel AISI 316L coatings was investigated using electron backscattered diffraction and transmission electron microscopy. The results show that the alloy 316L undergoes discontinuous dynamic recrystallization under conditions of moderate Zener-Hollomon parameter during friction surfacing. - Highlights: Black-Right-Pointing-Pointer Dynamic recrystallization in alloy 316L friction surfaced coatings is examined. Black-Right-Pointing-Pointer Friction surfacing leads to discontinuous dynamic recrystallization in alloy 316L. Black-Right-Pointing-Pointer Strain rates in friction surfacing exceed 400 s{sup -1}. Black-Right-Pointing-Pointer Estimated grain size matches well with experimental observations in 316L coatings.

  12. Surface fatigue life of carburized and hardened M50NiL and AISI 9310 spur gears and rolling-contact test bars

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Bamberger, Eric N.

    1989-01-01

    Spur gear endurance tests and rolling-element surface tests were conducted to investigate vacuum-induction-melted, vacuum-arc-melted (VIM-VAR) M50NiL steel for use as a gear steel in advanced aircraft applications, to determine its endurance characteristics, and to compare the results with those for standard VAR and VIM-VAR AISI 9310 gear material. Tests were conducted with spur gears and rolling-contact bars manufactured from VIM-VAR M50NiL and VAR and VIM-VAR AISI 9310. The gear pitch diameter was 8.9 cm (3.5 in.). Gear test conditions were an inlet oil temperature of 320 K (116 F), and outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. Bench rolling-element fatigue tests were conducted at ambient temperatures with a bar speed of 12,500 rpm and a maximum Hertz stress of 4.83 GPA (700 ksi). The VIM-VAR M50NiL gears had a surface fatigue life that was 4.5 and 11.5 times that for VIM-VAR and VAR AISI 9310 gears, respectively. The surface fatigue life of the VIM-VAR M50NiL rolling-contact bars was 13.2 and 21.6 times that for the VIM-VAR and VAR AISI 9310, respectively. The VIM-VAR M50NiL material was shown to have good resistance to fracture through a fatigue spall and to have fatigue life far superior to that of both VIM-VAR and VAR AISI 9310 gears and rolling-contact bars.

  13. Relations of Counterface Hardness with Wear Behavior and Tribo-Oxide Layer of AISI H13 Steel

    NASA Astrophysics Data System (ADS)

    Zhang, Q. Y.; Wang, S. Q.; Li, X. X.; Zhou, Y.; Chen, K. M.; Cui, X. H.

    2016-09-01

    Dry sliding wear tests of AISI H13 steel (50 HRC) against AISI D2 steel counterface with three hardness levels (55, 50, and 42 HRC) were performed at 298 K to 873 K (25 °C to 600 °C). The relations of counterface hardness with the wear behavior and tribo-oxide layer of AISI H13 steel were explored. When sliding against the different-hardness counterface, H13 steel presents appreciably changed wear behavior as a function of temperature. For H d/H p (the hardness ratio of disk to pin) > 1, the wear rate increases with the increase of temperature, but the wear rate variation is roughly inversed for H d/H p < 1. For H d/H p = 1, the wear rate first decreases to reach the lowest value at 473 K (200 °C) and then rapidly increases with the increase of temperature. The lowest wear rate appears at 298 K (25 °C) for H d/H p > 1, at 474 K (200 °C) for H d/H p = 1, and at 673 K (400 °C) for H d/H p < 1. As no-oxide tribolayer exists below 473 K (200 °C), the wear behavior roughly complies with Archard's equation; adhesive and abrasive wear prevail, regardless of H d/H p. As tribo-oxide layer exists at 473 K (200 °C) or above, the wear behavior depends on the tribo-oxide layer and thermal strength of the substrate, i.e., the stability of the tribo-oxide layer. Oxidative mild wear prevails at 473 K to 873 K (200 °C to 600 °C) for H d/H p < 1 and merely at 473 K (200 °C) for H d/H p = 1. However, a mild-to-severe transition of oxidative wear occurs at 473 K to 873 K (200 °C to 600 °C) for H d/H p > 1 and at 673 K to 873 K (400 °C to 600 °C) for H d/H p = 1. These findings suggest that the tribo-oxide layers are liable to exist stably for H d/H p ≤ 1 but to readily delaminate for H d/H p > 1.

  14. Coated carbide drill performance under soluble coconut oil lubricant and nanoparticle enhanced MQL in drilling AISI P20

    NASA Astrophysics Data System (ADS)

    Jamil, N. A. M.; Azmi, A. I.; Fairuz, M. A.

    2016-02-01

    This research experimentally investigates the performance of a TiAlN coated carbide drill bit in drilling AISI P20 through two different kinds of lubricants, namely; soluble coconut oil (SCO) and nanoparticle-enhanced coconut oil (NECO) under minimum quantity lubrication system. The tool life and tool wear mechanism were studied using various cutting speeds of 50, 100 and 150 m/min with a constant feed of 0.01 mm/rev. Since the flank wear land was not regular along the cutting edge, the average flank wear (VB) was measured at several points using image analysis software. The drills were inspected using a scanning electron microscope to further elucidate the wear mechanism. The result indicates that drilling with the nanoparticle- enhanced lubricant was better in resisting the wear and improving the drill life to some extent

  15. Fractographic evaluation of creep effects on strain-controlled fatigue-cracking of AISI 304LC and 316 stainless steel

    NASA Technical Reports Server (NTRS)

    Oldrieve, R. E.

    1978-01-01

    Analysis of high temperature low cycle fatigue of AISI 304LC and 316 stainless steels by the method of strainrange partitioning results in four separate strainrange versus life relationships, depending upon the way in which creep-strain and plastic strain are combined within a cycle. Fractography is used in this investigation of the creep-fatigue interaction associated with these cycles. The PP and PC-cycle fractures were transgranular. The PC-cycle resulted in fewer cycles of initiation and shorter total cyclic life for the same applied inelastic strainrange. The CC-cycle had mixed transgranular and intergranular fracture, fewer cycles of initiation and shorter cycle life than PP or PC. The CP-cycle had fully integranular cracking, and failed in fewer cycles than were required for cracks to initate for PP,PC, and CC.

  16. Tribo-electrochemical characterization of hafnium multilayer systems deposited on nitride/vanadium nitride AISI 4140 steel

    NASA Astrophysics Data System (ADS)

    Mora, M.; Vera, E.; Aperador, W.

    2016-02-01

    In this work is presented the synergistic behaviour among corrosion/wear (tribocorrosion) of the multilayer coatings hafnium nitride/vanadium nitride [HfN/VN]n. The multilayers were deposited on AISI 4140 steel using the technique of physical vapor deposition PVD magnetron sputtering, the tests were performed using a pin-on-disk tribometer, which has an adapted potentiostat galvanostat with three-electrode electrochemical cell. Tribocorrosive parameters such as: Friction coefficient between the coating and the counter body (100 Cr6 steel ball); Polarization resistance by means of electrochemical impedance spectroscopy technique and corrosion rate by polarization curves were determined. It was observed an increase in the polarization resistance, a decrease in the corrosion rate and a low coefficient of friction in comparison with the substrate, due to an increase on the number of bilayers.

  17. Quantifying Cutting and Wearing Behaviors of TiN- and CrN-Coated AISI 1070 Steel

    PubMed Central

    Cakan, Ahmet; Ozkaner, Vedat; Yildirim, Mustafa M.

    2008-01-01

    Hard coatings such as titanium nitride (TiN) and chromium nitride (CrN) are widely used in cutting and forming tools against wear and corrosion. In the present study, hard coating films were deposited onto AISI 1070 steels by a cathodic arc evaporation plating (CAVP) technique. These samples were subjected to wear in a conventional lathe for investigating the tribological behaviour of coating structure, and prenitrided subsurface composition was characterized using scanning electron microscopy (SEM), line scan analyses and X-ray diffraction (XRD). The wear properties of TiN- and CrN-coated samples were determined using an on-line monitoring system. The results show that TiN-coated samples demonstrate higher wear resistance than CrN-coated samples.

  18. Corrosion-fatigue behavior of an annealed AISI 1045 carbon steel coated with electroless nickel-phosphorus

    SciTech Connect

    Pertuz, A.; Chitty, J.A.; Puchi, E.S. ); Hintermann, H. . Faculty of Sciences)

    1999-08-01

    The influence of an industrial electroless nickel-phosphorus deposit on the corrosion-fatigue properties of an annealed AISI 1045 steel has been investigated. For this purpose, three corrosive media were selected: distilled water and two NaCl solutions of different concentration (3 and 5%) in distilled water. Corrosion-fatigue tests were conducted at alternating stress levels ranging between 219 and 329 MPa at a frequency of 50 Hz. The corrosion-fatigue properties of the coated and uncoated substrates are very similar when testing is conducted in salty water. However, for testing in distilled water the corrosion-fatigue properties of coated substrates were diminished in relation to the uncoated material. The fractographic analysis of the fracture surfaces revealed the presence of fatigue marks within the electroless nickel-phosphorus deposit, which indicate that the fracture mechanism of the coating is associated to the cyclic loading of the material.

  19. Effect of postweld treatment on the fatigue crack growth rate of electron-beam-welded AISI 4130 steel

    NASA Astrophysics Data System (ADS)

    Wang, Chien-Chun; Chang, Yih

    1996-10-01

    This article studies the effect of in-chamber electron beam and ex-chamber furnace postweld treatments on the fatigue crack growth rate of electron-beam-welded AISI 4130 steel. Mechanical properties of the weldment are evaluated by tensile testing, while the fatigue properties are investigated by a fatigue crack propagation method. Microstructural examination shows that both postweld treatments temper the weldment by the appropriate control of beam pattern width, input beam energy, and furnace temperature. In addition, the ductility, strength, and microhardness of the weldment also reflect this tempering effect. The fatigue crack growth rate is decreased after both postweld treatments. This is mainly caused by the existence of a toughened microstructure and relief of the residual stress due to the fact that (1) the residual stress becomes more compressive as more beam energy is delivered into the samples and (2) postweld furnace tempering effectively releases the tensile stress into a compressive stress state.

  20. Influence of PC-GTAW Parameters on the Microstructural and Mechanical Properties of Thin AISI 1008 Steel Joints

    NASA Astrophysics Data System (ADS)

    Kumar, Ravindra; Anant, Ramkishor; Ghosh, P. K.; Kumar, Ankit; Agrawal, B. P.

    2016-09-01

    Butt weld joints are prepared using pulse current gas tungsten arc welding out of thin sheets of AISI 1008 steel using various combinations of pulse parameters. During welding, the welding speed was kept high, but with the increase of welding speed the mean current was also increased to get the required weld joint at the constant heat input. The use of pulse current has led to improvement in mechanical and metallurgical properties of weld joints. It has resulted in less development of humping which is a common problem with high-speed welding. The undercut or dipped weld face is not observed severe. The tensile strength and hardness are enhanced by 12.5 and 12%. The increase of tensile strength and hardness is justified through TEM micrograph showing the presence of dislocation.

  1. Application of Deep Cryogenic Treatment to Uncoated Tungsten Carbide Inserts in the Turning of AISI 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Özbek, Nursel Altan; Çİçek, Adem; Gülesİn, Mahmut; Özbek, Onur

    2016-09-01

    This study investigated the effects of deep cryogenic treatment (DCT) on the wear performance of uncoated tungsten carbide inserts. AISI 304 austenitic stainless steel, widely used in industry, was selected as the workpiece material. Cutting experiments showed that the amount of wear significantly increased with increasing cutting speed. In addition, it was found that DCT contributed to the wear resistance of the turning inserts. The treated turning inserts were less worn by 48 and 38 pct in terms of crater wear and notch wear, respectively, whereas they exhibited up to 18 pct superior wear performance in terms of flank wear. This was attributed to the precipitation of new and finer η-carbides and their homogeneous distribution in the microstructure of the tungsten carbide material after deep cryogenic treatment. Analyses via image processing, hardness measurements, and SEM observations confirmed these findings.

  2. Microstructural Evolutions During Annealing of Plastically Deformed AISI 304 Austenitic Stainless Steel: Martensite Reversion, Grain Refinement, Recrystallization, and Grain Growth

    NASA Astrophysics Data System (ADS)

    Naghizadeh, Meysam; Mirzadeh, Hamed

    2016-08-01

    Microstructural evolutions during annealing of a plastically deformed AISI 304 stainless steel were investigated. Three distinct stages were identified for the reversion of strain-induced martensite to austenite, which were followed by the recrystallization of the retained austenite phase and overall grain growth. It was shown that the primary recrystallization of the retained austenite postpones the formation of an equiaxed microstructure, which coincides with the coarsening of the very fine reversed grains. The latter can effectively impair the usefulness of this thermomechanical treatment for grain refinement at both high and low annealing temperatures. The final grain growth stage, however, was found to be significant at high annealing temperatures, which makes it difficult to control the reversion annealing process for enhancement of mechanical properties. Conclusively, this work unravels the important microstructural evolution stages during reversion annealing and can shed light on the requirements and limitations of this efficient grain refining approach.

  3. Comparison of Roller Burnishing Method with Other Hole Surface Finishing Processes Applied on AISI 304 Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Akkurt, Adnan

    2011-08-01

    Component surface quality and selection of the optimum material are the main factors determining the performance of components used in machine manufacturing. The level of hole surface quality can be evaluated by the measurements regarding surface roughness, micro-hardness, and cylindricity. In this study, data had been obtained for different hole drilling methods. The characteristics of materials obtained after applications were compared for different hole-finishing processes to identify best hole drilling method. AISI 304 austenitic stainless steel material was used. Surface finishing of holes were performed using drilling, turning, reaming, grinding, honing, and roller burnishing methods. The results of the study show that the roller burnishing method gives the best results for mechanical, metallurgical properties, and hole surface quality of the material. On the other hand, the worst characteristics were obtained in the drilling method.

  4. Influence of PC-GTAW Parameters on the Microstructural and Mechanical Properties of Thin AISI 1008 Steel Joints

    NASA Astrophysics Data System (ADS)

    Kumar, Ravindra; Anant, Ramkishor; Ghosh, P. K.; Kumar, Ankit; Agrawal, B. P.

    2016-07-01

    Butt weld joints are prepared using pulse current gas tungsten arc welding out of thin sheets of AISI 1008 steel using various combinations of pulse parameters. During welding, the welding speed was kept high, but with the increase of welding speed the mean current was also increased to get the required weld joint at the constant heat input. The use of pulse current has led to improvement in mechanical and metallurgical properties of weld joints. It has resulted in less development of humping which is a common problem with high-speed welding. The undercut or dipped weld face is not observed severe. The tensile strength and hardness are enhanced by 12.5 and 12%. The increase of tensile strength and hardness is justified through TEM micrograph showing the presence of dislocation.

  5. Effect of polishing treatment and thermal oxidation on the total hemispherical thermal emittance of austenitic stainless steel AISI 321

    SciTech Connect

    Sharma, V.C.

    1982-07-01

    The optimum value of the hemispherical thermal emittance (epsilonh) of austenitic stainless steel (SS AISI 321, polished with ''AB Polishing Alumina'' of particle sizes 0.05, 0.3, and 5.0 /sigma phi/m and abrasives of various grit sizes, is found to be 0.13 + or - 0.01 and is significantly lower than the corresponding value of 0.23 + or - 0.01 for the unpolished samples. Although the epsilonh value at a given firing temperatur is constant, a small but systematic upward trend exists when the temperature is raised from 823 to 1293 K. At a firing temperature of 1293 K and for firing times of 3 to 15 min. epsilonh increases from 0.15 to 0.22 + or - 0.01.

  6. Effects of nitrogen ion implantation time on tungsten films deposited by DC magnetron sputtering on AISI 410 martensitic stainless steel

    NASA Astrophysics Data System (ADS)

    Malau, Viktor; Ilman, Mochammad Noer; Iswanto, Priyo Tri; Jatisukamto, Gaguk

    2016-03-01

    Nitrogen ion implantation time on tungsten thin film deposited on surface of AISI 410 steel has been performed. Tungsten thin film produced by dc magnetron sputtering method was deposited on AISI 410 martensitic stainless steel substrates, and then the nitrogen ions were implanted on tungsten thin film. The objective of this research is to investigate the effects of implantation deposition time on surface roughness, microhardness, specific wear and corrosion rate of nitrogen implanted on tungsten film. Magnetron sputtering process was performed by using plasma gas of argon (Ar) to bombardier tungsten target (W) in a vacuum chamber with a pressure of 7.6 x 10-2 torr, a voltage of 300 V, a sputter current of 80 mA for sputtered time of 10 minutes. Nitrogen implantation on tungsten film was done with an initial pressure of 3x10-6 mbar, a fluence of 2 x 1017 ions/cm2, an energy of 100 keV and implantation deposition times of 0, 20, 30 and 40 minutes. The surface roughness, microhardness, specific wear and corrosion rate of the films were evaluated by surfcorder test, Vickers microhardness test, wear test and potentiostat (galvanostat) test respectively. The results show that the nitrogen ions implanted deposition time on tungsten film can modify the surface roughness, microhardness, specific wear and corrosion rate. The minimum surface roughness, specific wear and corrosion rate can be obtained for implantation time of 20 minutes and the maximum microhardness of the film is 329 VHN (Vickers Hardness Number) for implantation time of 30 minutes. The specific wear and corrosion rate of the film depend directly on the surface roughness.

  7. Stability research on polydopamine and immobilized albumin on 316L stainless steel

    PubMed Central

    Xie, Lingxia; Deng, Jinchuan; Zhuang, Weihua; Luo, Rifang; Wang, Jin; Huang, Nan; Wang, Yunbing

    2016-01-01

    In this study, the polydopamine (PDA) film was coated on polished 316Lss and then thermally treated at 150 °C (labeled as PDA-Th150), and the stability of coatings was also investigated. Straining test indicated that PDA-Th150 coating performed better in affording sufficient adherence to 316 L SS substrate. Moreover, both PDA and PDA-Th150 coating suffered slight swelling during immersion in deionized water (pH = 6.5). X-ray photoelectron spectroscopy results showed that during immersion, latent nucleophilic reaction via amines inside PDA coating occurred. This led to an enhanced cross-linking and thus gradually promoted the coating stability. Moreover, larger amount of bovine serum albumin (BSA) was immobilized onto PDA-Th150 coating and performed well in anti-platelet adhesion. A high retention of immobilized BSA was observed even after immersion for 30 days. These tests suggested that PDA was stable enough and performed well in surface functionalization, which might enrich the research and application of PDA. PMID:27699058

  8. Stability research on polydopamine and immobilized albumin on 316L stainless steel

    PubMed Central

    Xie, Lingxia; Deng, Jinchuan; Zhuang, Weihua; Luo, Rifang; Wang, Jin; Huang, Nan; Wang, Yunbing

    2016-01-01

    In this study, the polydopamine (PDA) film was coated on polished 316Lss and then thermally treated at 150 °C (labeled as PDA-Th150), and the stability of coatings was also investigated. Straining test indicated that PDA-Th150 coating performed better in affording sufficient adherence to 316 L SS substrate. Moreover, both PDA and PDA-Th150 coating suffered slight swelling during immersion in deionized water (pH = 6.5). X-ray photoelectron spectroscopy results showed that during immersion, latent nucleophilic reaction via amines inside PDA coating occurred. This led to an enhanced cross-linking and thus gradually promoted the coating stability. Moreover, larger amount of bovine serum albumin (BSA) was immobilized onto PDA-Th150 coating and performed well in anti-platelet adhesion. A high retention of immobilized BSA was observed even after immersion for 30 days. These tests suggested that PDA was stable enough and performed well in surface functionalization, which might enrich the research and application of PDA.

  9. Surface nanostructuring of Ni, Ti, and 316L stainless steel using ultrafast laser interactions

    NASA Astrophysics Data System (ADS)

    Gill, Matt; Perrie, Walter; Fox, Peter; O'Neill, William

    2005-04-01

    The generation of surface periodic structures (SPS) on laser machined surfaces is known to occur when exciting the surface near the ablation threshold using short pulse laser exposure. These effects were first observed in the late 1960s and have remained a laboratory curiosity. Although well studied at nanosecond timescales there have been limited number of studies at ultrafast timescales. We have investigated the conditions necessary to generate short and long-range periodic structures using ultrafast laser pulses at λ =775nm and 387 nm which may find application in the field of surface engineering. This work examines the formation of SPS on a range of materials including Ni, Ti and SS316 and their dependence on fluence and polarisation.

  10. Comparative MRI compatibility of 316 L stainless steel alloy and nickel-titanium alloy stents.

    PubMed

    Holton, Andrea; Walsh, Edward; Anayiotos, Andreas; Pohost, Gerald; Venugopalan, Ramakrishna

    2002-01-01

    The initial success of coronary stenting is leading to a proliferation in peripheral stenting. A significant portion of the stents used in a clinical setting are made of 316 low carbon stainless steel (SS). Other alloys that have been used for stent manufacture include tantalum, MP35N, and nickel-titanium (NiTi). The ferromagnetic properties of SS cause the production of artifacts in magnetic resonance imaging (MRI). The NiTi alloys, in addition to being known for their shape memory or superelastic properties, have been shown to exhibit reduced interference in MRI. Thus, the objective of this study was to determine the comparative MRI compatibility of SS and NiTi stents. Both gradient echo and spin-echo images were obtained at 1.5 and 4.1 T field strengths. The imaging of stents of identical geometry but differing compositions permitted the quantification of artifacts produced due to device composition by normalizing the radio frequency shielding effects. These images were analyzed for magnitude and spatial extent of signal loss within the lumen and outside the stent. B1 mapping was used to quantify the attenuation throughout the image. The SS stent caused significant signal loss and did not allow for visibility of the lumen. However, the NiTi stent caused only minor artifacting and even allowed for visualization of the signal from within the lumen. In addition, adjustments to the flip angle of standard imaging protocols were shown to improve the quality of signal from within the lumen. PMID:12549230

  11. Mg-Doped Hydroxyapatite/Chitosan Composite Coated 316L Stainless Steel Implants for Biomedical Applications.

    PubMed

    Sutha, S; Dhineshbabu, N R; Prabhu, M; Rajendran, V

    2015-06-01

    In this investigation, ultrasonication process was used for the synthesis of magnesium doped nano-hydroxyapatite (MH) (0, 1, 2, and 3 mol% of Mg concentration) particles with controlled size and surface morphology. The size of the prepared MH particles was in the range of 20-100 nm with narrow distribution. Increase in the concentration of Mg reduced the particle size distribution from 60 to 40 nm. On incorporation of Mg in HAp lattice, an increase of 20-66 nm in specific surface area was observed in microporous HAp particles. XRF and XRD patterns reveal that the particles possess stoichiometric composition with reduced crystallinity with respect to the Mg concentration. Surface morphology of MH/chitosan (CTS) coated implant was found to be uniform without any defects. The corrosion rate of the implant decreased with increase in Mg concentration. The in vitro formation of bonelike apatite layer on the surface of the MH/CTS coated implant was observed from simulated body fluid studies. The antimicrobial activity of the MH/CTS composites against gram-positive and gram-negative bacterial strains indicated that increasing Mg concentration enhanced antimicrobial properties. Nanoindentation analysis of apatite coated implant surface reveals that the mechanical property depends on the concentration of magnesium in HAp. From the cytotoxicity analysis against NIH 3T3 fibroblast, it was observed that the Mg incorporated HAp/CTS composite was less toxic than the MHO/CTS composite. From this result, it was concluded that the MH/CTS nanocomposites coated implant is the excellent material for implants.

  12. Use of sputter-deposited 316L stainless steel ultrathin films for microbial influenced corrosion studies

    SciTech Connect

    Suci, P.A.; Geesey, G.G.; Pedraza, A.J.; Godbole, M.J.

    1993-12-31

    Ultra thin films (12nm) were sputter deposited onto cylindrical germanium internal reflection elements pre-coated with a thin (2 nm) layer of Cr{sub 2}O{sub 3}. Two crystals were inserted into Circle cell flow-through chambers and mounted on the optical bench of an Fourier Transform Infrared (FT-IR) spectrometer. One chamber was maintained as a sterile control while the other was sequentially inoculated with four bacterial species: Psudomonas aeruginosa, Bacillus subtillis, Hafnia alvei, and Desulfovibrio gigas, in that order. The water absorption band (1640cm{sup -4}) was monitored and used to follow that deterioration of the ultra thin films. In this respect, the sterile control and inoculated films exhibited only slight differences during the 1000h course of the experiment. Assay of the visible biofilm that has accumulated on the surface of the inoculated crystal after 1000h revealed that the film incorporated viable cells from all four strains.

  13. Wear testing under high load conditionsThe effect of ``anti-scuff'' additions to AISI 3135, 52100 and 9310 steels introduced by ion implantation and ion beam mixing

    NASA Astrophysics Data System (ADS)

    Hartley, N. E. W.; Hirvonen, J. K.

    1983-05-01

    There is a need to eliminate the sudden onset of severe adhesive wear ("scuffing") in high performance hardened steels (e.g. AISI 9310) under arduous load conditions. We have investigated the friction and wear behavior of three ion implanted and ion beam mixed steels under simulated scuffing conditions using a Falex friction and wear tester. This machine enabled tests to be carried out at a load of 700 lb (318 kg), corresponding to a mean contact pressure of approximately 20 000 psi (i.e., 1×10 8 N/m 2) which was sufficient to induce scuffing. A series of lower load tests at 200 lb (91 kg) load (5.2 × 10 7 N/m 2) enabled the longer term wear performance of various ion/substrate combinations to be measured. The frictional force experienced during wear testing was used to assess the degree of scuffing, and the amount of material worn away was measured on the Falex tester or by subsequent weight loss determinations, depending on the type of test. The following ions were implanted: C +, N +, P +, Ti +, Cr +, Mo +, and Ta +, chosen in order to evaluate the effects of intermetallic additions (C, N, P), alloys elements (Ti, Cr), and anti-scuff elements (Mo, Ta). In addition some thin ( ˜1000 Å) vacuum evaporated layers of Si, V, Ni, Nb, Sn, Mo, Ta and W were prepared, and in some cases intermixed with N + ions at a fluence of typically 2×10 17/cm 2, to compare with the effects of ion implantation. Under the low load conditions the wear rate of AISI 3135 steel (1.5% Ni, 0.65% Cr alloy tool steel) was found to be reduced by a factor 3 as a result of N + implantation under low load, in agreement with previous work reported elsewhere, whereas other ions gave inconclusive results. The 52100 steel (a through-hardened martensitic bearing steel) showed marked improvements after Ti + implantation, revealing a sensitivity to fluence which correlated with known dry sliding behaviour of this steel modified by titanium implantations. Ta + and Mo + implantations into 9310 steel (a

  14. Examination of Compatibility of Potentially Cavitation-Resistant Modifications of Type 316LN Stainless Steel with Mercury in a Thermal Convection Loop

    SciTech Connect

    Pawel, SJ

    2002-08-29

    A 316L stainless steel thermal convection loop (TCL) containing a variety of stainless steel coupons circulated mercury for 2000 h. The TCL conditions included a maximum temperature of 307 C, a maximum temperature gradient of 90 C, and a Hg velocity of about 1.4 m/min. In addition to mill-annealed/surface-ground 316LN coupons serving as the baseline material, other coupons included 316LN that was 50% cold-worked, 316LN that was given a proprietary surface hardening treatment termed ''kolsterizing,'' and Nitronic 60. The purpose of this test was to examine Hg compatibility with these modest variations of annealed 31 6LN stainless steel that are considered potential improvements over annealed 31 6LN for cavitation-erosion resistance in the Spallation Neutron Source (SNS) target containment system. The results indicated negligible weight change for each coupon type, no significant indication of attack or surface roughening, and generally no interaction with Hg.

  15. Employing Ti nano-powder dielectric to enhance surface characteristics in electrical discharge machining of AISI D2 steel

    NASA Astrophysics Data System (ADS)

    Marashi, Houriyeh; Sarhan, Ahmed A. D.; Hamdi, Mohd

    2015-12-01

    Manufacturing components with superior surface characteristics is challenging when electrical discharge machining (EDM) is employed for mass production. The aim of this research is to enhance the characteristics of AISI D2 steel surface machined with EDM through adding Ti nano-powder to dielectric under various machining parameters, including discharge duration (Ton) and peak current (I). Surface roughness profilometer, FESEM and AFM analysis were utilized to reveal the machined surface characteristics in terms of surface roughness, surface morphology and surface micro-defects. Moreover, EDX analysis was performed in order to evaluate the atomic deposition of Ti nano-powder on the surface. The concentration of Ti nano-powder in dielectric was also examined using ESEM and EDX. According to the results, the addition of Ti nano-powder to dielectric notably enhanced the surface morphology and surface roughness at all machining parameters except Ton = 340 μs. Of these parameters, maximum enhancement was observed at Ton = 210 μs, where the material removal rate and average surface roughness improved by ∼69 and ∼35% for peak current of 6 and 12 A, respectively. Elemental analysis signified negligible Ti deposition on the machined surface while the atomic concentration of Ti was increased around the crack areas.

  16. Effects of strain-induced martensite and its reversion on the magnetic properties of AISI 201 austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Souza Filho, I. R.; Sandim, M. J. R.; Cohen, R.; Nagamine, L. C. C. M.; Hoffmann, J.; Bolmaro, R. E.; Sandim, H. R. Z.

    2016-12-01

    Strain-induced martensite (SIM) and its reversion in a cold-rolled AISI 201 austenitic stainless steel was studied by means of magnetic properties, light optical (LOM) and scanning electron (SEM) microscopy, electron backscatter diffraction (EBSD), texture measurements, and Vickers microhardness testing. According to Thermo-calc© predictions, the BCC phase (residual δ-ferrite and SIM) is expected to be stable until 600 °C. The current material was cold rolled up to 60% thickness reduction and submitted to both isothermal and stepwise annealing up to 800 °C. Magnetic measurements were taken during annealing (in situ) of the samples and also for their post mortem conditions. The Curie temperatures (Tc) of residual δ-ferrite and SIM have similar values between 550 and 600 °C. Besides Tc, the focused magnetic parameters were saturation magnetization (Ms), remanent magnetization (MR), and coercive field (Hc). SIM reversion was found to occur in the range of 600-700 °C in good agreement with Thermo-calc© predictions. The microstructures of the material, annealed at 600 and 700 °C for 1 h, were investigated via EBSD. Microtexture measurements for these samples revealed that the texture components were mainly those found for the 60% cold rolled material. This is an evidence that the SIM reversion occurred by an athermal mechanism.

  17. Determination of Neutron Exposure of AISI 304 Stainless Steel from a BWR Top Guide using Retrospective Dosimetry

    SciTech Connect

    Greenwood, Lawrence R.; Garner, Francis A.; Oliver, Brian M.; Bruemmer, Stephen M.

    2007-03-31

    Retrospective dosimetry was used to determine the accumulated neutron exposure of AISI 304 stainless steel removed from the top guide of a boiling water reactor located at the Oyster Creek nuclear power station. The material was removed from areas adjacent to cracks that were observed after ~20 years of operation. Using the plant operational history and a variety of measurements of various radioisotopes or non-radioactive transmutation products produced by irradiation, it was possible to determine the integrated flux spectra experienced by the cracked region and to specify the accumulated displacement dose. Dose estimates on two separate specimens adjacent to the cracks were found to average 1.5 ± 0.2 dpa, possibly reflecting some uncertainty in measurement but more likely suggesting a small gradient in neutron flux-spectra within the section from which the various analysis specimens were cut. This report demonstrates that it is possible to examine defective components lying outside of the core region and where neutron flux-spectra are not well known, and to use the induced transmutation products to determine the neutron exposure with some confidence by using the examined specimen as its own dosimeter.

  18. The corrosion protection of AISI(TM) 1010 steel by organic and inorganic zinc-rich primers

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.

    1995-01-01

    The behavior of zinc-rich primer-coated AISI 1010 steel in 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR), were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electromechanical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 1010 steel cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high current between the steel cathode and both zinc-rich primer anodes (38.8 and 135.2 microns A/sq cm for the organic and inorganic primers, respectively). The results of corrosion rate determinations demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. EIS equivalent circuit parameters confirmed this conclusion. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application on solid rocket booster steel hardware.

  19. Microstructure and Mechanical Properties of Plasma Arc Brazed AISI 304L Stainless Steel and Galvanized Steel Plates

    NASA Astrophysics Data System (ADS)

    Jin, Yajuan; Li, Ruifeng; Yu, Zhishui; Wang, Yu

    2016-04-01

    Plasma arc brazing is used to join the AISI 304L stainless steel and galvanized steel plate butt joints with the CuSi3Mn1 filler wire. The effect of parameters on weld surface appearance, interfacial microstructure, and composition distribution in the joint was studied. The microhardness and mechanical tests were conducted to determine the mechanical properties of the welded specimens. The results indicated that good appearance, bead shape, and sufficient metallurgical bonding could be obtained when the brazing process was performed with a wire feeding speed of 0.8 m/min, plasma gas flow rate of 3.0 l/min, welding current of 100 A, and welding speed of 27 cm/min. During plasma arc brazing process, the top corner of the stainless steel and galvanized steel plate were heated and melted, and the melted quantity of stainless steel was much more than that of the galvanized steel due to the thermal conductivity coefficient difference between the dissimilar materials. The microhardness test results shows that the microhardness value gradually increased from the side of the galvanized steel to the stainless steel in the joint, and it is good for improving the mechanical properties of joint. The tensile strength was a little higher than that of the brazing filler, and the fracture position of weld joint was at the base metal of galvanized steel plate.

  20. Corrosion behavior and tensile properties of AISI 316LN stainless steel exposed to flowing sodium at 823 K

    SciTech Connect

    Pillai, S.R.; Barasi, N.S.; Khatak, H.S.; Terrance, A.L.E.; Kale, R.D.; Rajan, M.; Rajan, K.K.

    2000-02-01

    Austenitic stainless steel of the grade AISI 316 LN was exposed to flowing sodium in a loop at 823 K for 6,000 h to examine the corrosion and mass-transfer behavior. The specimens were incorporated in specially designed sample holders in the loop. These were retrieved and examined by various metallurgical techniques. Specimens were also subjected to thermal aging in the same sample holder to aid in separating the consequences of exposure to sodium from those cause by mere thermal effects. Microstructural investigations have revealed that thermal aging caused the precipitation of carbides at the grain boundaries. Exposure to sodium caused the leaching of elements such as chromium and nickel from the specimen. Loss of nickel from the austenite phase promoted the generation of ferrite phase. Microhardness investigation revealed the hardening of the sodium-exposed surface. Analysis using an electron Probe Microanalyzer revealed that the surface of the steel was both carburized and nitrided. Tensile tests indicated that there is no appreciable difference in the yield strength (YS) and ultimate tensile strength (UTS) of the thermally aged and sodium-exposed specimens when compared with the material in the as-received condition. However, the thermally aged and sodium-exposed specimens showed a decrease in the uniform elongation and total elongation at rupture, perhaps due to carburization and nitridation.

  1. Effects of strain and strain-induced α'-martensite on passive films in AISI 304 austenitic stainless steel.

    PubMed

    Lv, Jinlong; Luo, Hongyun

    2014-01-01

    In this paper, the effects of strain and heat treatment on strain-induced α'-martensite of AISI 304 stainless steel tubes were measured by X-ray diffraction. Moreover, the effects of strain and content of α'-martensite on passivated property on the surface of the material in borate buffer solution were evaluated by electrochemical technique. The results showed that the volume fraction of α'-martensite increased gradually with the increase of tensile strain for as-received and solid solution samples. However, α'-martensite in as-received sample was more than that in the solid solution sample. The electrochemical impedance spectroscopy results showed that the solid solution treatment improved corrosion resistance of the steel, especially for samples with small strain. Moreover, acceptor densities were always higher than donor densities for as-received and solid solution samples. With the increase of strain, the increase tendency of acceptor density was more significant than that of donor density. We also found that the total density of the acceptor and donor almost increased linearly with the increase of α'-martensite. The present results indicated that the increased acceptor density might lead to the decreased corrosion resistance of the steel.

  2. Correlation between surface physicochemical properties and the release of iron from stainless steel AISI 304 in biological media.

    PubMed

    Hedberg, Yolanda; Karlsson, Maria-Elisa; Blomberg, Eva; Odnevall Wallinder, Inger; Hedberg, Jonas

    2014-10-01

    Stainless steel is widely used in biological environments, for example as implant material or in food applications, where adsorption-controlled ligand-induced metal release is of importance from a corrosion, health, and food safety perspective. The objective of this study was to elucidate potential correlations between surface energy and wettability of stainless steel surfaces and the release of iron in complexing biological media. This was accomplished by studying changes in surface energies calculated from contact angle measurements, surface oxide composition (X-ray photoelectron spectroscopy), and released iron (graphite furnace atomic absorption spectroscopy) for stainless steel grade AISI 304 immersed in fluids containing bovine serum albumin or citric acid, and non-complexing fluids such as NaCl, NaOH, and HNO3. It was shown that the surface wettability and polar surface energy components were all influenced by adventitious atmospheric carbon (surface contamination of low molecular weight), rather than differences in surface oxide composition in non-complexing solutions. Adsorption of both BSA and citrate, which resulted in ligand-induced metal release, strongly influenced the wettability and the surface energy, and correlated well with the measured released amount of iron.

  3. Finite Element Analysis of Cross Rolling on AISI 304 Stainless Steel: Prediction of Stress and Strain Fields

    NASA Astrophysics Data System (ADS)

    Rout, Matruprasad; Pal, Surjya Kanta; Singh, Shiv Brat

    2016-05-01

    Studies on the effect of strain path during rolling has been carried out for a long time, but the same has not been done using Finite Element Analysis (FEA). Change in strain path affects the state variables in the rolled plate like stress, strain, temperature etc. In the current work, Finite Element Analysis for cross rolling of AISI 304 austenitic stainless steel has been carried out by rotating the plate by 90° in between the passes. To analyze stress and strain fields in the material for cross rolling, a full 3D model of work-roll and plate has been developed using rigid-viscoplastic finite element method. The stress and strain fields, considering von-Mises yield criteria, are calculated by using updated Lagrangian method. In addition to these, the model also calculates the normal pressure and strain rate distribution in the plate during cross rolling. The nature of the variations of stress and strain fields in the plate, predicted by the model, is in good agreement with the previously published works for unidirectional rolling.

  4. The effect of Zr-implantation on the thermal oxidation and aqueous corrosion of AISI 321 stainless steel

    NASA Astrophysics Data System (ADS)

    Noli, F.; Misaelides, P.; Giorginis, G.; Baumann, H.; Hatzidimitriou, A.

    1995-02-01

    The effect of Zr-implantation (energy: 40 keV, dose: 1 × 10 17 ions/cm 2) on the oxidation of AISI 321 austenitic stainless steel (Fe/Cr18/Ni8/Ti) has been studied at temperatures of 450, 550 and 650°C, in air. The duration of the oxidation was varied between one and six days. The oxygen distribution on the oxidized samples has been determined using the 16O(d, p) 17O nuclear reaction whereas the zirconium depth profile by means of Rutherford backscattering spectroscopy (RBS) using α-particles as projectiles. X-ray photoelectron spectroscopy (XPS) was used as support to these measurements. The morphology and the surface microstructure of the specimens were investigated by scanning electron and scanning transmission electron microscopy (SEM and STEM). The evaluation of the data has indicated that the implantation of Zr-ions leads to a chromium depletion in the near-surface layers and enhances the oxidation of the implanted samples compared to the initial material. Electrochemical experiments of the Zr-implanted steel performed in 1N sulphuric acid solution (H 2SO 4 1N) showed an increase of the corrosion resistance.

  5. Oxidation and corrosion studies of Al-implanted stainless steel AISI 321 using nuclear reaction and electrochemical techniques

    NASA Astrophysics Data System (ADS)

    Noli, F.; Misaelides, P.; Spathis, P.; Pilakouta, M.; Baumann, H.

    1992-05-01

    The oxidation of Al-implanted (implantation energy 40 keV, dose 1016-1017 Al ions/cm2) AISI 321 stainless steel samples in air has been studied at temperatures between 450 and 650°C using the 16O(d,p)17O nuclear reaction. The determination of the distribution of the implanted Al atoms has been performed using the resonance at 992 keV of the 27Al(p,γ)28Si nuclear reaction. The determined oxygen profiles indicate that the implantation of 5×1016 and 1017 Al ions/cm2 leads to an improvement of the oxidation resistance of the studied steel samples. The passivation/corrosion behaviour of the Al-implanted steel samples in 0.5M aqueous sulphuric acid solution has also been investigated electrochemically using potentiodynamic and cyclovoltammetric techniques. The passivation potential values and the repassivation moving to more positive values indicate an improvement of the corrosion resistance of the Al-implanted steel samples.

  6. Tribological measurements on a Charnley-type artificial hip joint

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.

    1983-01-01

    A total hip simulator was used to determine the friction and wear properties of Charnley-type (316L stainless steel balls and sterile ultrahigh molecular weight polyethylene cups) hip prostheses. Three different sets of specimens were tested to 395,000, 101,500 and 233,000 walking cycles, respectively. All tests were run unlubricated, at ambient conditions (22 to 26 C, 30 to 50 percent relative humidity), at 30 walking cycles per minute, under a dynamic load simulating walking. Polyethylene cup wear rates ranged from 1.4 to 39 ten billions cu m which corresponds to dimensional losses of 4.0 to 11 microns per year. Although these wear rates are lower than those obtained from other hip simulators and from in vivo X-ray measurements, they are comparable when taking run-in and plastic deformation into account. Maximum tangential friction forces ranged from 93 to 129 N under variable load (267 to 3090 N range) and from 93 to 143 N under a static load of 3090 N. A portion of one test 250,000 walking cycles) run under dry air ( 1 percent relative humidity) yielded a wear rate almost 6 times greater than that obtained under wet air ( 70 percent relative humidity) conditions.

  7. Determination of corrosion rates for steel alloys in process solvent. Final technical report

    SciTech Connect

    Latos, E.J.

    1984-01-01

    The objectives of this program were to determine the corrosion rate, under static and dynamic conditions, of AISI 1010, 5 Cr-0.5 Mo, Type 304L and Type 316L steels in an SRC-I, V-178, coal-derived liquid at temperatures ranging from 550/sup 0/F (288/sup 0/C) to 700/sup 0/F (371/sup 0/C) and to analyze the after-test liquids for metal content, and physical and chemical properties to determine stability under these test conditions. In addition, the program included a study to determine the storage stability of the V-178 coal-derived liquid at 110/sup 0/F (43.3/sup 0/C) in air. 6 references, 32 figures, 35 tables.

  8. Influence of electroless nickel-phosphorus deposits on the corrosion-fatigue life of notched and unnotched samples of an AISI 1045 steel

    SciTech Connect

    Chitty, J.A.; Pertuz, A.; Puchi, E.S.; Hintermann, H.

    1999-02-01

    Electroless nickel-phosphorus deposits of approximately 10% phosphorus and about 20 {micro}m thickness are shown either to have no effect or sometimes to increase the corrosion-fatigue properties of a quenched and tempered AISI 1045 steel in the stress amplitude range of 481 to 687 MPa, in the presence of an aqueous solution of 3% sodium chloride. Such an increase is produced when the stress amplitude is below 516 MPa. For the notched specimens, no substantial differences are found between the fatigue life of the coated and uncoated specimens.

  9. AISI/DOE Technology Roadmap Program: A Technology of Low Coal Rate and High Productivity of RHF Ironmaking

    SciTech Connect

    Wei-Kao Lu

    2002-09-15

    An economical and environment-friendly ironmaking process based on heating the chemiexecy self-sufficient green balls of iron ore and coal in a hearth furnace is being developed with financial support from AISI members and DOE. DRI, which is hot (1400 C), dense (3.2 g/cm) and of high degree of metallization (95%), has been produced in laboratory and in a pilot plant in Genoa, Italy. Products of such quality have been made from American and Brazilian ores, BOF sludge, EAF dust/BOF sludge mixtures and millscale. The removal of zinc and lead from green balls by this process is essentially complete. In comparison with typical blast furnace operation, the new technology with a melter would have a lower total coal rate by 200kg.THM. The elimination of cokemaking and high temperature agglomeration steps, and a simpler gas handling system would lead to lower capital and operating costs. In comparison with commercial RHF practice it is different in atmosphere (fully oxidized at 1600 to 1650 C), in bed height (120 mm instead of 20-25 mm) and in pellet composition (much less coal but of higher VM). The combined effect leads to three times higher furnace productivity, lower coal consumption and superior DRI quality. The risk of re-oxidation (slag formation) and dusty operation are practiexecy eliminated. The process is stable, tolerant and independent of the size, shape and movement of the hearth. However, materials handling (e.g., discharge of hot DRI) and the exact energy savings have to be established in a larger furnace, straight or rotary, and in a continuous mode of operation.

  10. Advance Complex Liquid Nitriding of Stainless Steel AISI 321 Surface at 430 °C

    NASA Astrophysics Data System (ADS)

    Lin, Yuanhua; Wang, Jun; Zeng, Dezhi; Huang, Runbo; Fan, Hongyuan

    2013-09-01

    Liquid nitriding of type 321 austenite stainless steel was conducted at low temperature at 430 °C, using a type of a complex chemical heat-treatment; and the properties of the nitrided surface were evaluated. Experimental results revealed that a modified layer was formed on the surface with the thickness ranging from 2 to 30 μm varying with changing treatment time. When the stainless steel subjected to the advanced liquid nitriding less than 8 h at 430 °C, the main phase of the nitrided coating layer was the S phase generally. When the treatment time prolonged up to 16 h, S phase formed and partially transformed to CrN subsequently; and then the fine secondary CrN phase precipitated. All treatments performed in the current study can effectively improve the surface hardness. The nitrided layer thickness changed intensively with the increasing nitrided time. The growth of the nitride layer took place mainly by nitrogen diffusion according to the expected parabolic rate law. The highest hardness value obtained in this experiment was about 1400 Hv0.25. Low-temperature nitriding can improve the corrosion resistance of the 321 stainless steel against diluted vitriolic acid. The immerse test results revealed that the sample nitrided for 16 h had the best corrosion resistance than the others. SEM examinations indicated that after nitriding, the corrosion mechanisms of the steel had changed from serious general corrosion of untreated sample to selectivity corrosion of nitrided samples in the diluted vitriolic acid.

  11. Effects of Deep Cryogenic Treatment on the Wear Resistance and Mechanical Properties of AISI H13 Hot-Work Tool Steel

    NASA Astrophysics Data System (ADS)

    Çiçek, Adem; Kara, Fuat; Kıvak, Turgay; Ekici, Ergün; Uygur, İlyas

    2015-11-01

    In this study, a number of wear and tensile tests were performed to elucidate the effects of deep cryogenic treatment on the wear behavior and mechanical properties (hardness and tensile strength) of AISI H13 tool steel. In accordance with this purpose, three different heat treatments (conventional heat treatment (CHT), deep cryogenic treatment (DCT), and deep cryogenic treatment and tempering (DCTT)) were applied to tool steel samples. DCT and DCTT samples were held in nitrogen gas at -145 °C for 24 h. Wear tests were conducted on a dry pin-on-disk device using two loads of 60 and 80 N, two sliding velocities of 0.8 and 1 m/s, and a wear distance of 1000 m. All test results showed that DCT improved the adhesive wear resistance and mechanical properties of AISI H13 steel. The formation of small-sized and uniformly distributed carbide particles and the transformation of retained austenite to martensite played an important role in the improvements in the wear resistance and mechanical properties. After cleavage fracture, the surfaces of all samples were characterized by the cracking of primary carbides, while the DCT and DCTT samples displayed microvoid formation by decohesion of the fine carbides precipitated during the cryo-tempering process.

  12. The effect of microstructure on the thermal fatigue resistance of investment cast and wrought AISI H13 hot work die steel

    SciTech Connect

    Hochanadel, P.W.; Edwards, G.R.; Maguire, M.C.; Baldwin, M.D.

    1995-07-01

    Variable thickness plate investment castings of AISI H13 hot work die steel were pour and characterized in the as-cast and heat treated conditions. The characterization included light microscopy and mechanical testing. Wrought samples of standard and premium grade H13 steel were heat treated and characterized similarly for comparison. Microstructural differences were observed in as-cast samples poured to different section thicknesses. Dendrite cell size and carbide morphology constituted the most prominent microstructural differences observed. After a full heat treatment, however, Microstructural differences between the wrought material and cast materials were slight regardless of section thickness. The mechanical properties of the cast and heat treated material proved similar to the properties of the standard heat treated wrought material. A thermal fatigue testing unit was designed and built to correlate the heat checking susceptibility of AISI H13 steel to its processing and consequent microstructural condition. Surface hardness decreased significantly with thermal cycling, and heat checking was noticed in as few as 50 cycles. Thermal softening and thermal fatigue susceptibility were quantified and discussed relative to the microstructural conditions created by processing and heat treatment. It was found that the premium grade wrought H13 steel provided the best overall resistance to heat checking; however, the heat-treat cast and as-cast H13 tool steel (made from standard grade wrought H13 tool steel) provided comparable resistance to heat checking in terms Of area fraction of heat checking and maximum crack length.

  13. Brazed joints of CBN grains and AISI 1045 steel with AgCuTi-TiC mixed powder as filler materials

    NASA Astrophysics Data System (ADS)

    Ding, Wen-Feng; Xu, Jiu-Hua; Chen, Zhen-Zhen; Su, Hong-Hua; Fu, Yu-Can

    2011-12-01

    The brazing process of cubic boron nitride (CBN) grains and AISI 1045 steel with AgCuTi-TiC mixed powder as a filler material was carried out. The joining strength and the interfacial microstructure were investigated. The experimental results indicate that the spreading of the molten filler material on AISI 1045 steel is decreased with the increase of TiC content. A good interface is formed between the TiC particulates and AgCuTi alloy through the wetting behavior. In the case of AgCuTi+16wt% TiC, the strength of the brazed steel-to-steel joints reached the highest value of 95 MPa dependent upon the reinforcement effect of TiC particles within the filler layer. Brazing resultants of TiB2, TiB, and TiN are produced at the interface of the CBN grains and the AgCuTi-TiC filler layer by virtue of the interdiffusion of B, N, and Ti atoms.

  14. A Simple Kinetic Model for the Growth of Fe2B Layers on AISI 1026 Steel During the Powder-pack Boriding

    NASA Astrophysics Data System (ADS)

    Flores-Rentería, M. A.; Ortiz-Domínguez, M.; Keddam, M.; Damián-Mejía, O.; Elias-Espinosa, M.; Flores-González, M. A.; Medina-Moreno, S. A.; Cruz-Avilés, A.; Villanueva-Ibañez, M.

    2015-02-01

    This work focused on the determination of boron diffusion coefficient through the Fe2B layers on AISI 1026 steel using a mathematical model. The suggested model solves the mass balance equation at the (Fe2B/substrate) interface. This thermochemical treatment was carried out in the temperature range of 1123-1273 K for a treatment time ranging from 2 to 8 h. The generated boride layers were characterized by different experimental techniques such as light optical microscopy, scanning electron microscopy, XRD analysis and the Daimler-Benz Rockwell-C indentation technique. As a result, the boron activation energy for AISI 1026 steel was estimated as 178.4 kJ/mol. Furthermore, this kinetic model was validated by comparing the experimental Fe2B layer thickness with the predicted one at a temperature of 1253 K for 5 h of treatment. A contour diagram relating the layer thickness to the boriding parameters was proposed to be used in practical applications.

  15. Friction and wear of selected metals and alloys in sliding contact with AISI 440 C stainless steel in liquid methane and in liquid natural gas

    NASA Technical Reports Server (NTRS)

    Wisander, D. W.

    1978-01-01

    Aluminum, titanium, beryllium, nickel, iron, copper, and several copper alloys were run in sliding contact with AISI 440C in liquid methane and natural gas. All of the metals run except copper and the copper alloys of tin and tin-lead showed severely galled wear scars. Friction coefficients varied from 0.2 to 1.0, the lowest being for copper, copper-17 wt. % tin, and copper-8 wt. % tin-22 wt. % lead. The wear rate for copper was two orders of magnitude lower than that of the other metals run. An additional order of magnitude of wear reduction was achieved by the addition of tin and/or lead to copper.

  16. An experimental analysis of process parameters to manufacture micro-channels in AISI H13 tempered steel by laser micro-milling

    NASA Astrophysics Data System (ADS)

    Teixidor, D.; Ferrer, I.; Ciurana, J.

    2012-04-01

    This paper reports the characterization of laser machining (milling) process to manufacture micro-channels in order to understand the incidence of process parameters on the final features. Selection of process operational parameters is highly critical for successful laser micromachining. A set of designed experiments is carried out in a pulsed Nd:YAG laser system using AISI H13 hardened tool steel as work material. Several micro-channels have been manufactured as micro-mold cavities varying parameters such as scanning speed (SS), pulse intensity (PI) and pulse frequency (PF). Results are obtained by evaluating the dimensions and the surface finish of the micro-channel. The dimensions and shape of the micro-channels produced with laser-micro-milling process exhibit variations. In general the use of low scanning speeds increases the quality of the feature in both surface finishing and dimensional.

  17. Comparison of surface roughness and chip characteristics obtained under different modes of lubrication during hard turning of AISI H13 tool work steel.

    NASA Astrophysics Data System (ADS)

    Raj, Anil; Wins, K. Leo Dev; Varadarajan, A. S.

    2016-09-01

    Surface roughness is one of the important parameters, which not only affects the service life of a component but also serves as a good index of machinability. Near Dry Machining, methods (NDM) are considered as sustainable alternative for workshops trying to bring down their dependence on cutting fluids and the hazards associated with their indiscriminate usage. The present work presents a comparison of the surface roughness and chip characteristics during hard turning of AISI H13 tool work steel using hard metal inserts under two popular NDM techniques namely the minimal fluid application and the Minimum Quantity Lubrication technique(MQL) using an experiment designed based on Taguchi's techniques. The statistical method of analysis of variance (ANOVA) was used to determine the relative significance of input parameters consisting of cutting speed, feed and depth of cut on the attainable surface finish and the chip characteristics. It was observed that the performance during minimal fluid application was better than that during MQL application.

  18. Combined bending-torsion fatigue reliability of AISI 4340 steel shafting with K sub t = 2.34. [stress concentration factor

    NASA Technical Reports Server (NTRS)

    Kececioglu, D.; Chester, L. B.; Dodge, T. M.

    1974-01-01

    Results generated by three, unique fatigue reliability research machines which can apply reversed bending loads combined with steady torque are presented. Six-inch long, AISI 4340 steel, grooved specimens with a stress concentration factor of 2.34 and R sub C 35/40 hardness were subjected to various combinations of these loads and cycled to failure. The generated cycles-to-failure and stress-to-failure data are statistically analyzed to develop distributional S-N and Goodman diagrams. Various failure theories are investigated to determine which one represents the data best. The effect of the groove and of the various combined bending-torsion loads on the S-N and Goodman diagrams are determined. Three design applications are presented. The third one illustrates the weight savings that may be achieved by designing for reliability.

  19. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    NASA Astrophysics Data System (ADS)

    García-Rentería, M. A.; López-Morelos, V. H.; García-Hernández, R.; Dzib-Pérez, L.; García-Ochoa, E. M.; González-Sánchez, J.

    2014-12-01

    The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O2 (M1) and 97% Ar + 3% N2 (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  20. Application of orthogonal array technique and particle swarm optimization approach in surface roughness modification when face milling AISI1045 steel parts

    NASA Astrophysics Data System (ADS)

    Azadi Moghaddam, Masoud; Kolahan, Farhad

    2016-12-01

    Face milling is an important and common machining operation because of its versatility and capability to produce various surfaces. Face milling is a machining process of removing material by the relative motion between a work piece and rotating cutter with multiple cutting edges. It is an interrupted cutting operation in which the teeth of the milling cutter enter and exit the work piece during each revolution. This paper is concerned with the experimental and numerical study of face milling of AISI1045. The proposed approach is based on statistical analysis on the experimental data gathered using Taguchi design matrix. Surface roughness is the most important performance characteristics of the face milling process. In this study the effect of input face milling process parameters on surface roughness of AISI1045 steel milled parts have been studied. The input parameters are cutting speed ( v), feed rate ( f z ) and depth of cut ( a p ). The experimental data are gathered using Taguchi L9 design matrix. In order to establish the relations between the input and the output parameters, various regression functions have been fitted on the data based on output characteristics. The significance of the process parameters on the quality characteristics of the process was also evaluated quantitatively using the analysis of variance method. Then, statistical analysis and validation experiments have been carried out to compare and select the best and most fitted models. In the last section of this research, mathematical model has been developed for surface roughness prediction using particle swarm optimization (PSO) on the basis of experimental results. The model developed for optimization has been validated by confirmation experiments. It has been found that the predicted roughness using PSO is in good agreement with the actual surface roughness.

  1. AISI Direct Steelmaking Program

    SciTech Connect

    Aukrust, E.

    1993-01-01

    Pilot plant trials with the horizontal vessel were completed. Design of a third pressurized vessel and an offgas cleaning and tempering system was completed. Installation is now underway. A basic study and a pre-engineering design of a 350,000-metric ton/y demonstration plant were completed, and efforts are underway to develop such a demonstration plant at a host steel company. Foreign filings have been prepared for the two-zone countercurrent smelter (patent applied for). Work with a water model of two-zone smelter was completed. The horizontal smelter program was completed. Trials were conducted to determine how sulfur is partitioned among the hot metal, slag, and offgas. Design of offgas cleaning and tempering loop was completed.

  2. Parameters in selective laser melting for processing metallic powders

    NASA Astrophysics Data System (ADS)

    Kurzynowski, Tomasz; Chlebus, Edward; Kuźnicka, Bogumiła; Reiner, Jacek

    2012-03-01

    The paper presents results of studies on Selective Laser Melting. SLM is an additive manufacturing technology which may be used to process almost all metallic materials in the form of powder. Types of energy emission sources, mainly fiber lasers and/or Nd:YAG laser with similar characteristics and the wavelength of 1,06 - 1,08 microns, are provided primarily for processing metallic powder materials with high absorption of laser radiation. The paper presents results of selected variable parameters (laser power, scanning time, scanning strategy) and fixed parameters such as the protective atmosphere (argon, nitrogen, helium), temperature, type and shape of the powder material. The thematic scope is very broad, so the work was focused on optimizing the process of selective laser micrometallurgy for producing fully dense parts. The density is closely linked with other two conditions: discontinuity of the microstructure (microcracks) and stability (repeatability) of the process. Materials used for the research were stainless steel 316L (AISI), tool steel H13 (AISI), and titanium alloy Ti6Al7Nb (ISO 5832-11). Studies were performed with a scanning electron microscope, a light microscopes, a confocal microscope and a μCT scanner.

  3. Comparative study of the native oxide on 316L stainless steel by XPS and ToF-SIMS

    SciTech Connect

    Tardio, Sabrina Abel, Marie-Laure; Castle, James E.; Watts, John F.; Carr, Robert H.

    2015-09-15

    The very thin native oxide film on stainless steel, of the order of 2 nm, is known to be readily modified by immersion in aqueous media. In this paper, X-ray photoelectron spectroscopy (XPS) and time of flight secondary ions mass spectrometry are employed to investigate the nature of the air-formed film and modification after water emersion. The film is described in terms of oxide, hydroxide, and water content. The preferential dissolution of iron is shown to occur on immersion. It is shown that a water absorbed layer and a hydroxide layer are present above the oxide-like passive film. The concentrations of water and hydroxide appear to be higher in the case of exposure to water. A secure method for the peak fitting of Fe2p and Cr2p XPS spectra of such films on their metallic substrates is described. The importance of XPS survey spectra is underlined and the feasibility of C{sub 60}{sup +} SIMS depth profiling of a thin oxide layer is shown.

  4. Parameters optimization of hybrid fiber laser-arc butt welding on 316L stainless steel using Kriging model and GA

    NASA Astrophysics Data System (ADS)

    Gao, Zhongmei; Shao, Xinyu; Jiang, Ping; Cao, Longchao; Zhou, Qi; Yue, Chen; Liu, Yang; Wang, Chunming

    2016-09-01

    It is of great significance to select appropriate welding process parameters for obtaining optimal weld geometry in hybrid laser-arc welding. An integrated optimization approach by combining Kriging model and GA is proposed to optimize process parameters. A four-factor, five-level experiment using Taguchi L25 is conducted considering laser power (P), welding current (A), distance between laser and arc (D) and traveling speed (V). Kriging model is adopted to approximate the relationship between process parameters and weld geometry, namely depth of penetration (DP), bead width (BW) and bead reinforcement (BR). The constructed Kriging model was used for parameters optimization by GA to maximize DP, minimize BW and ensure BR at a desired value. The effects of process parameters on weld geometry are analyzed. Microstructure and micro-hardness are also discussed. Verification experiments demonstrate that the obtained optimum values are in good agreement with experimental results.

  5. Evaluation of the structural steel corrosion behaviour, covered with epoxy-type paints, by means of electrochemical DC techniques

    NASA Astrophysics Data System (ADS)

    Salas, Y.; Guerrero, L.; Martinez, R.; Chicino, T.; Devia, C.

    2016-02-01

    In this work we have studied the behaviour of the electrochemical corrosion of structural steel AISI SAE 1007 with epoxy coatings, using epoxy-type paints, through techniques such as DC resistance Polarization and Potentio-dynamic tests. In order to determine potential and corrosion rates of these coatings, have been correlated this results with different used electrolytes. For this, coatings were characterized by thickness measurement and continuity measurements. The coatings showed a slight degradation in the testing time, due to defects present in their structure, and the attack by the electrolyte; however, epoxy coating system tends to react with the electrolytes based on their chemical composition.

  6. Influence of surface position along the working range of conoscopic holography sensors on dimensional verification of AISI 316 wire EDM machined surfaces.

    PubMed

    Fernández, Pedro; Blanco, David; Rico, Carlos; Valiño, Gonzalo; Mateos, Sabino

    2014-03-06

    Conoscopic holography (CH) is a non-contact interferometric technique used for surface digitization which presents several advantages over other optical techniques such as laser triangulation. Among others, the ability for the reconstruction of high-sloped surfaces stands out, and so does its lower dependence on surface optical properties. Nevertheless, similarly to other optical systems, adjustment of CH sensors requires an adequate selection of configuration parameters for ensuring a high quality surface digitizing. This should be done on a surface located as close as possible to the stand-off distance by tuning frequency (F) and power (P) until the quality indicators Signal-to-Noise Ratio (SNR) and signal envelope (Total) meet proper values. However, not all the points of an actual surface are located at the stand-off distance, but they could be located throughout the whole working range (WR). Thus, the quality of a digitized surface may not be uniform. The present work analyses how the quality of a reconstructed surface is affected by its relative position within the WR under different combinations of the parameters F and P. Experiments have been conducted on AISI 316 wire EDM machined flat surfaces. The number of high-quality points digitized as well as distance measurements between different surfaces throughout the WR allowed for comparing the metrological behaviour of the CH sensor with respect to a touch probe (TP) on a CMM.

  7. Characteristics of diamond-like carbon film synthesized on AISI 304 austenite stainless steel using plasma immersion ion implantation and deposition

    NASA Astrophysics Data System (ADS)

    Liang, J. H.; Chen, M. H.; Tsai, W. F.; Lee, S. C.; Ai, C. F.

    2007-04-01

    This study examines the characteristics of diamond-like carbon (DLC) film synthesized on AISI 304 austenite stainless steel by means of a hybrid process of plasma immersion ion implantation and deposition (PIII&D) maintained at 60 °C. The former and latter processes under investigation were carried out using methane (0-20 kV) and acetylene (1-2 kV, 0.13-0.40 Pa) plasmas, respectively. Glow discharge spectrometry (GDS), Raman scattering spectroscopy (RSS), atomic force microscopy (AFM), a nano-indentation probe (NIP) and a Rockwell-C hardness tester were employed to characterize, respectively, elemental depth profiles, sp3-to-sp2 ratio, surface morphology, hardness and adhesion strength of the DLC specimen. The results revealed that the mixing layer at the interface generated by plasma immersion ion implantation of methane at a higher voltage could enhance adhesive strength of the DLC film to the substrate. Furthermore, a higher sp3-to-sp2 ratio, a smoother surface, greater hardness, but weaker adhesion strength were obtained for the DLC film synthesized using plasma immersion ion deposition of acetylene at a lower bias voltage or higher gas pressure.

  8. Finite Element Modelling of the effect of tool rake angle on tool temperature and cutting force during high speed machining of AISI 4340 steel

    NASA Astrophysics Data System (ADS)

    Sulaiman, S.; Roshan, A.; Ariffin, M. K. A.

    2013-12-01

    In this paper, a Finite Element Method (FEM) based on the ABAQUS explicit software which involves Johnson-Cook material model was used to simulate cutting force and tool temperature during high speed machining (HSM) of AISI 4340 steel. In this simulation work, a tool rake angle ranging from 0° to 20° and a range of cutting speeds between 300 to 550 m/min was investigated. The purpose of this simulation analysis was to find optimum tool rake angle where cutting force is smallest as well as tool temperature is lowest during high speed machining. It was found that cutting forces to have a decreasing trend as rake angle increased to positive direction. The optimum rake angle observed between 10° and 18° due to decrease of cutting force as 20% for all simulated cutting speeds. In addition, increasing cutting tool rake angle over its optimum value had negative influence on tool's performance and led to an increase in cutting temperature. The results give a better understanding and recognition of the cutting tool design for high speed machining processes.

  9. Weldability Characteristics of Sintered Hot-Forged AISI 4135 Steel Produced through P/M Route by Using Pulsed Current Gas Tungsten Arc Welding

    NASA Astrophysics Data System (ADS)

    Joseph, Joby; Muthukumaran, S.; Pandey, K. S.

    2016-01-01

    Present investigation is an attempt to study the weldability characteristics of sintered hot-forged plates of AISI 4135 steel produced through powder metallurgy (P/M) route using matching filler materials of ER80S B2. Compacts of homogeneously blended elemental powders corresponding to the above steel were prepared on a universal testing machine (UTM) by taking pre-weighed powder blend with a suitable die, punch and bottom insert assembly. Indigenously developed ceramic coating was applied on the entire surface of the compacts in order to protect them from oxidation during sintering. Sintered preforms were hot forged to flat, approximately rectangular plates, welded by pulsed current gas tungsten arc welding (PCGTAW) processes with aforementioned filler materials. Microstructural, tensile and hardness evaluations revealed that PCGTAW process with low heat input could produce weldments of good quality with almost nil defects. It was established that PCGTAW joints possess improved tensile properties compared to the base metal and it was mainly attributed to lower heat input, resulting in finer fusion zone grains and higher fusion zone hardness. Thus, the present investigation opens a new and demanding field in research.

  10. Influence of Surface Position along the Working Range of Conoscopic Holography Sensors on Dimensional Verification of AISI 316 Wire EDM Machined Surfaces

    PubMed Central

    Fernández, Pedro; Blanco, David; Rico, Carlos; Valiño, Gonzalo; Mateos, Sabino

    2014-01-01

    Conoscopic holography (CH) is a non-contact interferometric technique used for surface digitization which presents several advantages over other optical techniques such as laser triangulation. Among others, the ability for the reconstruction of high-sloped surfaces stands out, and so does its lower dependence on surface optical properties. Nevertheless, similarly to other optical systems, adjustment of CH sensors requires an adequate selection of configuration parameters for ensuring a high quality surface digitizing. This should be done on a surface located as close as possible to the stand-off distance by tuning frequency (F) and power (P) until the quality indicators Signal-to-Noise Ratio (SNR) and signal envelope (Total) meet proper values. However, not all the points of an actual surface are located at the stand-off distance, but they could be located throughout the whole working range (WR). Thus, the quality of a digitized surface may not be uniform. The present work analyses how the quality of a reconstructed surface is affected by its relative position within the WR under different combinations of the parameters F and P. Experiments have been conducted on AISI 316 wire EDM machined flat surfaces. The number of high-quality points digitized as well as distance measurements between different surfaces throughout the WR allowed for comparing the metrological behaviour of the CH sensor with respect to a touch probe (TP) on a CMM. PMID:24662452

  11. Microstructural Characterization and Wear Behavior of Nano-Boride Dispersed Coating on AISI 304 Stainless Steel by Hybrid High Velocity Oxy-Fuel Spraying Laser Surface Melting

    NASA Astrophysics Data System (ADS)

    Sharma, Prashant; Majumdar, Jyotsna Dutta

    2015-07-01

    The current study concerns the detailed microstructural characterization and investigation of wear behavior of nano-boride dispersed coating developed on AISI 304 stainless steel by high velocity oxy-fuel spray deposition of nickel-based alloy and subsequent laser melting. There is a significant refinement and homogenization of microstructure with improvement in microhardness due to laser surface melting (1200 VHN as compared to 945 VHN of as-sprayed and 250 VHN of as-received substrate). The high temperature phase stability of the as-coated and laser melted surface has been studied by differential scanning calorimeter followed by detailed phase analysis at room and elevated temperature. There is a significant improvement in wear resistance of laser melted surface as compared to as-sprayed and the as-received one due to increased hardness and reduced coefficient of friction. The mechanism of wear has been investigated in details. Corrosion resistance of the coating in a 3.56 wt pct NaCl solution is significantly improved (4.43 E-2 mm/year as compared to 5 E-1 mm/year of as-sprayed and 1.66 mm/year of as-received substrate) due to laser surface melting as compared to as-sprayed surface.

  12. Improvement in wear and corrosion resistance of AISI 1020 steel by high velocity oxy-fuel spray coating containing Ni-Cr-B-Si-Fe-C

    NASA Astrophysics Data System (ADS)

    Prince, M.; Thanu, A. Justin; Gopalakrishnan, P.

    2012-04-01

    In this investigation, AISI 1020 low carbon steel has been selected as the base material. The Ni based super alloy powder NiCrBSiFeC was sprayed on the base material using high velocity oxy-fuel spraying (HVOF) technique. The thickness of the coating was approximately 0.5 mm (500 μm). The coating was characterized using optical microscopy, Vickers microhardness testing, X-ray diffraction technique and scanning electron microscopy. Dry sliding wear tests were carried out at 3 m/s sliding speed under the load of 10 N for 1000 m sliding distance at various temperatures i.e., 35° C, 250° C and 350° C. The corrosion test was carried out in 1 M copper chloride in acetic acid solution. The polarization studies were also conducted for both base material and coating. The improvement in microhardness from 1.72 GPa (175 HV0.05) to 10.54 GPa (1075 HV0.05) was observed. The coatings exhibited 3-6 times improved wear resistance as compared with base material. Also, the corrosion rate was reduced by 3.5 times due to the presence of coatings.

  13. Results of steel corrosion tests in flowing liquid Pb/Bi at 420-600 °C after 2000 h

    NASA Astrophysics Data System (ADS)

    Müller, G.; Heinzel, A.; Konys, J.; Schumacher, G.; Weisenburger, A.; Zimmermann, F.; Engelko, V.; Rusanov, A.; Markov, V.

    2002-02-01

    Corrosion tests were carried out on austenitic AISI 316L and 1.4970 steels and on MANET steel up to 2000 h of exposure to flowing (up to 2 m/s) Pb/Bi. The concentration of oxygen in the liquid alloy was controlled at 10 -6 wt%. Specimens consisted of tube and rod sections in original state and after alloying of Al into the surface. After 2000 h of exposure at 420 and 550 °C the specimen surfaces were covered with an intact oxide layer which provided a good protection against corrosion attack of the liquid Pb/Bi alloy. After the same time corrosion attack at 600 °C was severe at the original AISI 316L steel specimens. The alloyed specimens containing FeAl on the surface of the alloyed layer still maintained an intact oxide layer with good corrosion protection up to 600 °C.

  14. Effects of laser power density on static and dynamic mechanical properties of dissimilar stainless steel welded joints

    NASA Astrophysics Data System (ADS)

    Wei, Yan-Peng; Li, Mao-Hui; Yu, Gang; Wu, Xian-Qian; Huang, Chen-Guang; Duan, Zhu-Ping

    2012-10-01

    The mechanical properties of laser welded joints under impact loadings such as explosion and car crash etc. are critical for the engineering designs. The hardness, static and dynamic mechanical properties of AISI304 and AISI316 L dissimilar stainless steel welded joints by CO2 laser were experimentally studied. The dynamic strain-stress curves at the strain rate around 103 s-1 were obtained by the split Hopkinson tensile bar (SHTB). The static mechanical properties of the welded joints have little changes with the laser power density and all fracture occurs at 316 L side. However, the strain rate sensitivity has a strong dependence on laser power density. The value of strain rate factor decreases with the increase of laser power density. The welded joint which may be applied for the impact loading can be obtained by reducing the laser power density in the case of welding quality assurance.

  15. Bacterial adhesion to diamond-like carbon as compared to stainless steel.

    PubMed

    Soininen, Antti; Tiainen, Veli-Matti; Konttinen, Yrjö T; van der Mei, Henny C; Busscher, Henk J; Sharma, Prashant K

    2009-08-01

    Recent studies suggest that diamond-like carbon (DLC) coatings are suitable candidates for application on biomedical devices and implants, due to their high hardness, low friction, high wear and corrosion resistance, chemical inertness, smoothness, and tissue and blood compatibility. However, most studies have neglected the potential susceptibility of DLC coatings to bacterial adhesion, which is the first step in the development of implant-related infections. This study compares adhesion of seven bacterial strains, commonly implicated in implant-related infections, to tetrahedral amorphous carbon, with their adhesion to AISI 316L surgical steel. The results show that bacterial adhesion to DLC was similar to the adhesion to commonly used stainless steel. This suggests that DLC coating can be advantageously used on implants made of AISI 316L or other materials without increasing the risk to implant-related infections.

  16. Dissolution and oxidation behaviour of various austenitic steels and Ni rich alloys in lead-bismuth eutectic at 520 °C

    NASA Astrophysics Data System (ADS)

    Roy, Marion; Martinelli, Laure; Ginestar, Kevin; Favergeon, Jérôme; Moulin, Gérard

    2016-01-01

    Ten austenitic steels and Ni rich alloys were tested in static lead-bismuth eutectic (LBE) at 520 °C in order to obtain a selection of austenitic steels having promising corrosion behaviour in LBE. A test of 1850 h was carried out with a dissolved oxygen concentration between 10-9 and 5 10-4 g kg-1. The combination of thermodynamic of the studied system and literature results leads to the determination of an expression of the dissolved oxygen content in LBE as a function of temperature: RT(K)ln[O](wt%) = -57584/T(K) -55.876T(K) + 254546 (R is the gas constant in J mol-1 K-1). This relation can be considered as a threshold of oxygen content above which only oxidation is observed on the AISI 316L and AISI 304L austenitic alloys in static LBE between 400 °C and 600 °C. The oxygen content during the test leads to both dissolution and oxidation of the samples during the first 190 h and leads to pure oxidation for the rest of the test. Results of mixed oxidation and dissolution test showed that only four types of corrosion behaviour were observed: usual austenitic steels and Ni rich alloys behaviour including the reference alloy 17Cr-12Ni-2.5Mo (AISI 316LN), the 20Cr-31Ni alloy one, the Si containing alloy one and the Al containing alloy one. According to the proposed criteria of oxidation and dissolution kinetics, silicon rich alloys and aluminum rich alloy presented a promising corrosion behaviour.

  17. Improvement of adhesion and barrier properties of biomedical stainless steel by deposition of YSZ coatings using RF magnetron sputtering

    SciTech Connect

    Sánchez-Hernández, Z.E.; Domínguez-Crespo, M.A.; Torres-Huerta, A.M.; Onofre-Bustamante, E.; Andraca Adame, J.; Dorantes-Rosales, H.

    2014-05-01

    The AISI 316L stainless steel (SS) has been widely used in both artificial knee and hip joints in biomedical applications. In the present study, yttria stabilized zirconia (YSZ, ZrO{sub 2} + 8% Y{sub 2}O{sub 3}) films were deposited on AISI 316L SS by radio-frequency magnetron sputtering using different power densities (50–250 W) and deposition times (30–120 min) from a YSZ target. The crystallographic orientation and surface morphology were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effects of the surface modification on the corrosion performance of AISI 316L SS were evaluated in phosphate buffered saline (PBS) solution using an electrochemical test on both the virgin and coated samples. The YSZ coatings have a (111) preferred orientation during crystal growth along the c-axis for short deposition times (30–60 min), whereas a polycrystalline structure forms during deposition times from 90 to 120 min. The corrosion protective character of the YSZ coatings depends on the crystal size and film thickness. A significant increase in adhesion and corrosion resistance by at least a factor of 46 and a higher breakdown potential were obtained for the deposited coatings at 200 W (120 min). - Highlights: • Well-formed and protective YSZ coatings were achieved on AISI 316L SS substrates. • Films grown at high power and long deposition time have polycrystalline structures. • The crystal size varies from ∼ 5 to 30 nm as both power and deposition time increased. • The differences of corrosion resistance are attributed to internal film structure.

  18. Spectroscopic investigation of the vapor plume during laser processing of AISI 52100 steel using a high brightness diode-pumped Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Douglass, David Mark

    2001-12-01

    Laser atomic absorption spectroscopy was employed to investigate the plasma created during processing of AISI 52100 steel with a diode-pumped Nd:YAG slab laser. A tunable ring-dye laser was focused into various points throughout the plume and the dye laser frequency detuned across several low-lying transitions of Fe I. Absorption profiles were collected at time intervals from 3-12μs, average powers from 80-260W and a speed of 0.8mm/s. The absorption profiles were used to calculate atomic densities using an Abel inversion technique and the electronic temperatures via atomic Boltzmann plots. The resulting atomic densities and temperatures of the plume were mapped graphically. Broadening mechanisms were considered, and emission spectroscopy and time-of-flight measurements were also obtained. Atomic densities were determined for the lower energy levels of three Fe I transitions. The peak densities were on the order of 1016, 1014 and 1013cm-3 for the lower levels of the 446.29, 446.03 and 446.78nm transitions, respectively. Line broadening was determined to be a combination Doppler and Stark broadening. At early delays, as the power increased, the densities of the transitions studied increased at the top portions of the plume. The plume also widened with power. The lifetime of plume atoms in excited states was no more than 12μs. The peak electronic temperatures within the plume ranged from 4800-7500K. If time averaged, these temperatures were in agreement with time-averaged temperatures from emission spectroscopy. The highest temperatures were at 3μs with cooling rates on the order of 108K/s. The average gas temperature was determined from Doppler widths and found to be 6000K, thus indicating similar electronic and gas temperatures. The kinetic velocity of the iron atoms was on the order of 103m/s and in agreement with time-of-flight velocity measurements. The depth of penetration in the coupons was 1.3-5.1 mm. The remelt layer was composed of martensite, and the

  19. In vitro biomineralization by osteoblast-like cells. I. Retardation of tissue mineralization by metal salts.

    PubMed

    Morais, S; Sousa, J P; Fernandes, M H; Carvalho, G S

    1998-01-01

    The cytocompatibility of stainless steel 316L (SS 316L) corrosion products was investigated with particular focus on the dose- and time-effect of electrochemically dissolved SS and the corresponding separate metal ions on osteogenic bone marrow derived cells. Type AISI 316L stainless steel (Fe 63.9%, Cr 18.0%, Ni 12.5%, Mo 2.8%, Si 1.2%, Mn 1.6% and C 0.025%, weight for weight) was anodically dissolved in Hank's Balanced Salt Solution (HBSS) and diluted to the following concentrations: 500 microg ml(-1) of Fe, 122 microg ml(-1) of Cr and 101 microg ml(-1) of Ni, as estimated by atomic absorption spectrometry. Similarly, salt solutions containing 50 microg ml(-1) of Fe (FeCl3 x 6H2O), 122 microg ml(-1) of Cr (CrCl3 x 6H2O) or 101 microg ml(-1) of Ni (NiNO3) were prepared. All solutions were diluted 1:10(3), 1:10(4) and 1:10(5) and their effects on cell proliferation and function of rabbit bone marrow cells were studied up to 28 days of culture. Bone marrow cells (second subculture) were cultured in alpha-Minimal Essential Medium (alpha-MEM) supplemented with 10% fetal bovine serum 10(-8) mol l(-1) dexamethasone, 2.52 x 10(-4) mol l(-1) ascorbic acid and 10(-2) mol l(-1) beta-glycerophosphate. The osteoblast response to the presence of metal ions was evaluated by biochemical assays (enzymatic reduction of MTT for evaluation of cell viability/proliferation, and estimation of alkaline phosphatase (ALP) activity) and histochemical assays (identification of ALP positive cells and calcium and phosphates deposits). Results suggest a decrease in the expression of the osteoblast phenotype in the presence of ion and alloy solutions. Stainless steel corrosion products elicited slight effects but the corresponding metal ions produced pronounced effects on the osteoblast phenotype, namely an alteration in the levels and temporal expression of ALP and lower and retarded tissue mineralization ability. PMID:9678845

  20. Corrosion behavior of stainless steel and nickel-base alloys in molten carbonate

    SciTech Connect

    Vossen, J.P.T.; Plomp, L.; Rietveld, G.; Wit, J.H.W. de

    1995-10-01

    The corrosion behavior of five commercially available alloys (AISI 316L, AISI 310S, Inconel 601, Thermax 4762, and Kanthal A1) in molten carbonate under reducing gas atmospheres was investigated with cyclic voltammetry and quasi-stationary polarization curve measurements. The reactions that proceed on these materials at distinct potentials could be deduced by comparison of the cyclic voltammograms and polarization curves with those of pure metals and model alloys. The shape of the polarization curves of all materials strongly depends on the preceding electrochemical treatment. A polarization curve recorded immediately after immersion of a sample resulted in a high anodic current. This implies that the passivation of the materials is poor. When a specimen was conditioned at {minus}1,060 mV for 10 h before recording the polarization curve, the anodic current diminished, which indicates passivation. This occurred for all materials except AISI 316L. A ranking of the corrosion properties was determined from polarization curves of samples that had been conditioned assuming the current densities to be representative. The resistance against corrosion of the alloys increases in the order: AISI 316LAISI 310S

  1. Tensile and fatigue data for irradiated and unirradiated AISI 310 stainless steel and titanium - 5 percent aluminum - 2.5 percent tin: Application of the method of universal slopes

    NASA Technical Reports Server (NTRS)

    Debogdan, C. E.

    1973-01-01

    Irradiated and unirradiated tensile and fatigue specimens of AISI 310 stainless steel and Ti-5Al-2.5Sn were tested in the range of 100 to 10,000 cycles to failure to determine the applicability of the method of universal slopes to irradiated materials. Tensile data for both materials showed a decrease in ductility and increase in ultimate tensile strength due to irradiation. Irradiation caused a maximum change in fatigue life of only 15 to 20 percent for both materials. The method of universal slopes predicted all the fatigue data for the 310 SS (irradiated as well as unirradiated) within a life factor of 2. For the titanium alloy, 95 percent of the data was predicted within a life factor of 3.

  2. Preliminary Comparison of Properties between Ni-electroplated Stainless Steel Parts Fabricated with Laser Additive Manufacturing and Conventional Machining

    NASA Astrophysics Data System (ADS)

    Mäkinen, Mika; Jauhiainen, Eeva; Matilainen, Ville-Pekka; Riihimäki, Jaakko; Ritvanen, Jussi; Piili, Heidi; Salminen, Antti

    Laser additive manufacturing (LAM) is a fabrication technology, which enables production of complex parts from metallic materials with mechanical properties comparable to those of conventionally machined parts. These LAM parts are manufactured via melting metallic powder layer by layer with laser beam. Aim of this study is to define preliminarily the possibilities of using electroplating to supreme surface properties. Electrodeposited nickel and chromium as well as electroless (autocatalytic) deposited nickel was used to enhance laser additive manufactured and machined parts properties, like corrosion resistance, friction and wearing. All test pieces in this study were manufactured with a modified research AM equipment, equal to commercial EOS M series. The laser system used for tests was IPG 200 W CW fiber laser. The material used in this study for additive manufacturing was commercial stainless steel powder grade named SS316L. This SS316L is not equal to AISI 316L grade, but commercial name of this kind of powder is widely known in additive manufacturing as SS316L. Material used for fabrication of comparison test pieces (i.e. conventionally manufactured) was AISI 316L stainless steel bar. Electroplating was done in matrix cell and electroless was done in plastic sink properties of plated parts were tested within acetic acid salt spray corrosion chamber (AASS, SFS-EN-ISO 9227 standard). Adhesion of coating, friction and wearing properties were tested with Pin-On-Rod machine. Results show that in these preliminary tests, LAM parts and machined parts have certain differences due to manufacturing route and surface conditions. These have an effect on electroplated and electroless parts features on adhesion, corrosion, wearing and friction. However, further and more detailed studies are needed to fully understand these phenomena.

  3. The AISI direct steelmaking program

    SciTech Connect

    Aukrust, E. ); Downing, K.B. )

    1991-01-01

    After six months of operation of the pilot plant, the viability of in-bath smelting combined with a high level of post combustion has been demonstrated, and the opportunity exists for an early commercialization of the direct ironmaking part of the process while we continue to research direct steelmaking. The program should be of equal interest to integrated and electric furnace producers. Smelting of ore provides virgin iron units. Additionally, the process has the flexibility of melting scrap and varying the ore-to-scrap ratio over wide ranges. This process does not require coke, thus eliminating the cokemaking operation, a major source of environmental concern.

  4. External stress-corrosion cracking of a 1.22-m-diameter type 316 stainless steel air valve

    NASA Technical Reports Server (NTRS)

    Moore, Thomas J.; Telesman, Jack; Moore, Allan S.; Johnson, Dereck F.; Kuivinen, David E.

    1993-01-01

    An investigation was conducted to determine the cause of the failure of a massive AISI Type 316 stainless steel valve which controlled combustion air to a jet engine test facility. Several through-the-wall cracks were present near welded joints in the valve skirt. The valve had been in outdoor service for 18 years. Samples were taken in the cracked regions for metallographic and chemical analyses. Insulating material and sources of water mist in the vicinity of the failed valve were analyzed for chlorides. A scanning electron microscope was used to determine whether foreign elements were present in a crack. On the basis of the information generated, the failure was characterized as external stress-corrosion cracking. The cracking resulted from a combination of residual tensile stress from welding and the presence of aqueous chlorides. Recommended countermeasures are included.

  5. Surface-protein interactions on different stainless steel grades: effects of protein adsorption, surface changes and metal release.

    PubMed

    Hedberg, Y; Wang, X; Hedberg, J; Lundin, M; Blomberg, E; Wallinder, I Odnevall

    2013-04-01

    Implantation using stainless steels (SS) is an example where an understanding of protein-induced metal release from SS is important when assessing potential toxicological risks. Here, the protein-induced metal release was investigated for austenitic (AISI 304, 310, and 316L), ferritic (AISI 430), and duplex (AISI 2205) grades in a phosphate buffered saline (PBS, pH 7.4) solution containing either bovine serum albumin (BSA) or lysozyme (LSZ). The results show that both BSA and LSZ induce a significant enrichment of chromium in the surface oxide of all stainless steel grades. Both proteins induced an enhanced extent of released iron, chromium, nickel and manganese, very significant in the case of BSA (up to 40-fold increase), whereas both proteins reduced the corrosion resistance of SS, with the reverse situation for iron metal (reduced corrosion rates and reduced metal release in the presence of proteins). A full monolayer coverage is necessary to induce the effects observed.

  6. Development of corrosion-resistant improved Al-doped austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Kondo, Keietsu; Miwa, Yukio; Okubo, Nariaki; Kaji, Yoshiyuki; Tsukada, Takashi

    2011-10-01

    Aluminum-doped type 316L SS (316L/Al) has been developed for the purpose of suppressing the degradation of corrosion resistance induced by irradiation in austenitic stainless steels (SSs). The electrochemical corrosion properties of this material were estimated after Ni-ion irradiation at a temperature range from 330 °C to 550 °C. When irradiated at 550 °C up to 12 dpa, 316L/Al showed high corrosion resistance in the vicinity of grain boundaries (GBs) and in grains, while severe GB etching and local corrosion in grains were observed in irradiated 316L and 316 SS. It is supposed that aluminum enrichment was enhanced by high-temperature irradiation at GBs and in grains, to compensate for lost corrosion resistance induced by chromium depletion.

  7. An air-breathing single cell small proton exchange membrane fuel cell system with AB5-type metal hydride and an ultra-low voltage input boost converter

    NASA Astrophysics Data System (ADS)

    Akiyama, Kazuya; Matsumoto, Satoshi; Miyasaka, Akihiro; Shodai, Takahisa

    A new strategy for increasing the power density of an air-breathing small proton exchange membrane fuel cell (PEMFC) system for the main energy source of portable consumer electronics is presented. The small PEMFC system is composed of a single cell. Utilizing the output voltage of the single cell, we introduce a newly designed ultra-low voltage input boost converter. The boost converter can generate 4.1 V output from input sources with low voltage ranges, such as under 1.0 V. The cathode plate is made from a thin SUS 316L stainless steel plate and has ribs that prevent the cathode from bending. The hydrogen is supplied by a metal hydride (MH) tank cartridge. The MH tank contains highly packed AB5-type MH. The MH tank cartridge has a volume of 13.2 cm 3 and can absorb 6.7 L of hydrogen. The maximum power of the small PEMFC is 4.42 W at room temperature. Using 6.7 L of hydrogen, the small PEMFC can generate 11 Wh of electricity. The power density of the small PEMFC reaches 0.51 Wh cm -3. And the power density of the whole small PEMFC system, which contains the boost converter, a small Li-ion battery for a load absorber, and a case for the system, reaches 0.14 Wh cm -3. This value matches that of external Li-ion battery chargers for cell phones. We installed the small PEMFC system in a cell phone and confirmed the operations of calling, receiving, videophone, connecting to the Internet, and watching digital TV. And also confirmed that the small PEMFC system provides approximately 8.25 h of talk time, which is about three times as long as that for the original Li-ion battery.

  8. Synthesis of thoria nano-particles at low temperature through base electrogeneration on steel 316L surface: Effect of current density

    NASA Astrophysics Data System (ADS)

    Yousefi, Taher; Torab-Mostaedi, Meisam; Mobtaker, Hossein Ghasemi; Keshtkar, Ali Reza

    2016-10-01

    The strategy developed in this study, offers significant advantages (simplicity and cleanness of method and also a product purity and new morphology of the product) over the conventional routes for the synthesis of ThO2 nanostructure. The effect of current density on morphology was studied. The synthesized powder was characterized by means of Powder X-ray Diffraction (PXRD), Transmission Electron Microscopy (TEM, Phillips EM 2085) Brunauer-Emmett-Teller (BET) and Fourier Transform Infrared (FT-IR) spectroscopy. The results show that the current density has a great effect on the morphology of the samples. The average size of the particles decreases as the applied current density increases and the average size of the samples decreases from 50 to 15 nm when the current density increases from 2 to 5 mA cm-2.

  9. Improved corrosion resistance and interfacial contact resistance of 316L stainless-steel for proton exchange membrane fuel cell bipolar plates by chromizing surface treatment

    NASA Astrophysics Data System (ADS)

    Lee, S. B.; Cho, K. H.; Lee, W. G.; Jang, H.

    The electrochemical performance and electrical contact resistance of chromized 316 stainless-steel (SS) are investigated under simulated operating condition in a proton-exchange membrane fuel cell (PEMFC). The corrosion resistance of the chromized stainless steel is assessed by potentiodynamic and potentiostatic tests and the interfacial contact resistance (ICR) is examined by measuring the electrical contact resistance as a function of the compaction force. The results show that the chromizing surface treatment improves the corrosion resistance of the stainless steel due to the high-chromium concentration in the diffuse coating layer. On the other hand, the excess Chromium content on the surface increases the contact resistance of the steel plate to a level that is excessively high for commercial applications. This study examines the root cause of the high-contact resistance after chromizing and reports the optimum process to improve the corrosion resistance without sacrificing the ICR by obtaining a chrome carbide on the outer layer.

  10. Finite-element modelling of low-temperature autofrettage of thick-walled tubes of the austenitic stainless steel AISI 304 L: Part II. Thick-walled tube with cross-bore

    NASA Astrophysics Data System (ADS)

    Feng, H.; Donth, B.; Mughrabi, H.

    1998-01-01

    In part I, the autofrettage of a smooth thick-walled tube of the austenitic stainless steel AISI 304 L was studied by finite-element (FE) modelling. It was shown that low- temperature autofrettage is more efficient than autofrettage at room temperature, since it produces a larger beneficial compressive residual tangential (hoop) stress at the inner bore of the tube and hence permits a more significant enhancement of the fatigue resistance against pulsating internal pressure. The objective of the present study (part II) was to investigate the technically more relevant case of a thick-walled tube with a cross-bore made of the same steel. For this purpose, three-dimensional FE calculations were performed in order to characterize the influences of the autofrettage pressure and temperature on the stress and strain changes, in particular at the site of the cross-bore, also taking into account the effects of work hardening and reverse yielding. The results indicate that low-temperature autofrettage can also be applied advantageously in the case of thick-walled tubes with a cross-bore by virtue of the significantly larger residual compressive stresses, compared to room temperature autofrettage. From the quantitative FE calculations, the optimal combination of autofrettage temperature and pressure were concluded to lie in the range of 0965-0393/6/1/007/img1 to 0965-0393/6/1/007/img2, respectively. The calculated results were found to be in fair agreement with the measured values.

  11. Finite-element modelling of low-temperature autofrettage of thick-walled tubes of the austenitic stainless steel AISI 304 L: Part I. Smooth thick-walled tubes

    NASA Astrophysics Data System (ADS)

    Feng, H.; Mughrabi, H.; Donth, B.

    1998-01-01

    The stresses and strains introduced by low-temperature autofrettage of smooth thick-walled tubes made of the austenitic stainless steel AISI 304 L were modelled by the finite-element (FE) method. The objective was to show that low-temperature autofrettage is much more efficient than autofrettage at room temperature in enhancing the fatigue resistance by introducing a higher beneficial tangential (hoop) residual compressive stress at the inner part of the tube. Attention was paid to the influences of the autofrettage temperature and pressure, the work hardening and the reverse yielding on the residual stress components and on the total strain components of the tube. The FE calculations confirmed that more beneficial residual stress patterns can be attained by autofrettage at low rather than at room temperature. From the quantitative calculations, the optimal autofrettage temperature and pressure of the tube were concluded to be about 0965-0393/6/1/006/img1 and 4000 bar, respectively. The results of the calculations were shown to be in good agreement with recently measured data.

  12. Microstructure, Mechanical, and Scratch Resistance Properties of TiAlCrNbN-Graded Composite Coating Deposited on AISI H13 Steel Substrate with Pulsed DC Closed Field Unbalanced Magnetron Sputtering Method

    NASA Astrophysics Data System (ADS)

    Kara, Levent; Küçükömeroğlu, Tevfik; Baran, Özlem; Efeoğlu, İhsan; Yamamoto, Kenji

    2014-04-01

    Structure and adhesion properties of TiAlCrNbN coatings were investigated. These coatings were deposited onto AISI H13 steel substrate using pulsed dc closed field unbalanced magnetron sputtering at different deposition parameters including duty cycle, bias voltage, and working pressure. The coatings have been characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The TiAlCrNbN-graded composite coatings have a dense and columnar structure. The X-ray diffraction patterns of coatings exhibited predominantly c-TiAlCrN, h-NbN, and h-TiAlN reflections. Scratch resistance test showed that the highest adhesion strength was attained as 68 N at 2.5 μs duty time, 100 V bias voltages, and 3 × 10-3 Torr deposition parameters. The lowest adhesion strength was obtained as 55 N at 0.5 μs duty time, 50V bias voltage, and 2 × 10-3 Torr deposition parameters.

  13. Reversible stress-induced anomalies in the strain function of Nb3Sn wires

    NASA Astrophysics Data System (ADS)

    De Marzi, G.; Corato, V.; Muzzi, L.; della Corte, A.; Mondonico, G.; Seeber, B.; Senatore, C.

    2012-02-01

    The full-matrix set of combined temperature (4.2-14 K) and applied axial strain (ɛa) data for the bulk pinning force of a technological Nb3Sn wire (OST type-I) has been studied at fields up to 19 T by combining transport (variable ɛa) and magnetic (variable T) measurements. Some length of the wire was also jacketed with AISI 316L stainless steel, in order to apply a radial strain and to simulate the thermally induced axial compressive strain that the Nb3Sn wires experience in a cable-in-conduit-conductor (CICC). Within the framework of the unified scaling law, raw scaling data for the effective upper critical field, {B}_{{c2}}^{\\ast }(T,\\varepsilon ), have been used in order to experimentally determine the strain function, s(ɛ), of both the bare and the jacketed wires. A direct testing of the various proposed models for s(ɛ) has been carried out, including the power law, the deviatoric description and the polynomial form. All models adequately fit to the s(ɛ) of the bare wire, but in the jacketed wire none of them is able to describe the tensile strain region above the Ic maximum, where the enhanced radial compression cannot be neglected. The origin of the onset of a reduced Bc2 is also discussed.

  14. Improvement of electromechanical properties of an ITER internal tin Nb3Sn wire

    NASA Astrophysics Data System (ADS)

    Mondonico, G.; Seeber, B.; Senatore, C.; Flükiger, R.; Corato, V.; De Marzi, G.; Muzzi, L.

    2010-11-01

    The critical current of an internal tin Nb3Sn wire developed by Oxford Instruments, Superconducting Technology for International Thermonuclear Experimental Reactor (ITER) (OST type-I, billet No. 7567) has been studied under axial strain at fields between 12 and 19 T at 4.2 K. Simulating the situation in a cable in conduit, where thermally induced compressive strain is important, a single wire (strand) was jacketed with AISI 316L stainless steel. The reinforced wire shows an important increase in ɛm, the applied strain where Ic reaches its maximum, from 0.25% to 0.57%. In addition the irreversibility limit, ɛirr, is improved from 0.50% applied strain to >1.10%. It could also be shown that the Ic at zero intrinsic strain is almost identical. This demonstrates that jacketing does not influence the physical parameters of the original wire. Experimental data of the bare wire has been well fitted by different strain functions. However, it was not possible to model the data of the jacketed wire. There are indications that only models which take into account the multidimensional character of strain are able to describe the behavior but further development is required.

  15. Temperature effect on the corrosion mechanism of austenitic and martensitic steels in lead-bismuth

    NASA Astrophysics Data System (ADS)

    Benamati, G.; Fazio, C.; Piankova, H.; Rusanov, A.

    2002-02-01

    Compatibility tests on the austenitic AISI 316L and the martensitic MANET II steels in stagnant PbBi were performed at 573, 673 and 823 K with exposures up to 5000 h. The change of the corrosion mechanism with increasing temperature has been evaluated. The results showed that at 573 and 673 K a thin oxide layer growth on the surface of both steels. By increasing the temperature to 823 K both types of steels were attacked by the liquid metal and dissolution of the steel alloying elements has been observed. The herein-reported experimental activities were performed in collaboration with the IPPE of Obninsk, where preliminary dynamic tests were performed in the experimental facility CU-2. The Russian ferritic-martensitic steel EP823 has been exposed to flowing PbBi at 623, 723 and 823 K for 700 h. After 700 h of testing, the surface of the EP823 samples showed for the three temperatures a compact oxide layer.

  16. Estimation of the laser cutting operating cost by support vector regression methodology

    NASA Astrophysics Data System (ADS)

    Jović, Srđan; Radović, Aleksandar; Šarkoćević, Živče; Petković, Dalibor; Alizamir, Meysam

    2016-09-01

    Laser cutting is a popular manufacturing process utilized to cut various types of materials economically. The operating cost is affected by laser power, cutting speed, assist gas pressure, nozzle diameter and focus point position as well as the workpiece material. In this article, the process factors investigated were: laser power, cutting speed, air pressure and focal point position. The aim of this work is to relate the operating cost to the process parameters mentioned above. CO2 laser cutting of stainless steel of medical grade AISI316L has been investigated. The main goal was to analyze the operating cost through the laser power, cutting speed, air pressure, focal point position and material thickness. Since the laser operating cost is a complex, non-linear task, soft computing optimization algorithms can be used. Intelligent soft computing scheme support vector regression (SVR) was implemented. The performance of the proposed estimator was confirmed with the simulation results. The SVR results are then compared with artificial neural network and genetic programing. According to the results, a greater improvement in estimation accuracy can be achieved through the SVR compared to other soft computing methodologies. The new optimization methods benefit from the soft computing capabilities of global optimization and multiobjective optimization rather than choosing a starting point by trial and error and combining multiple criteria into a single criterion.

  17. Fatigue life enhancement of high reliability metallic components by laser shock processing

    NASA Astrophysics Data System (ADS)

    Ocaña, J. L.; Porro, J. A.; Díaz, M.; Ruiz de Lara, L.; Correa, C.; Peral, D.

    2015-03-01

    Laser shock processing (LSP) is increasingly applied as an effective technology for the improvement of metallic materials mechanical properties in different types of components as a means of enhancement of their mechanical behavior. As reported in the literature, a main effect resulting from the application of the LSP technique consists on the generation of relatively deep compression residual stresses field into metallic alloy pieces allowing the life improvement of the treated specimens against wear, crack growth and stress corrosion cracking. Additional results accomplished by the authors in the line of practical development of the LSP technique at an experimental level (aiming its integral assessment from an interrelated theoretical and experimental point of view) are presented in this paper. Concretely, experimental results on the residual stress profiles and associated mechanical properties modification successfully reached in typical materials under different LSP irradiation conditions are presented along with a practical correlated analysis on the protective character of the residual stress profiles obtained under different irradiation strategies. In this case, the specific behavior of a widely used material in high reliability components (especially in nuclear and biomedical applications) as AISI 316L is analyzed, the effect of possible "in-service" thermal conditions on the relaxation of the LSP effects being specifically characterized.

  18. Mechanical and anticorrosion properties of nanosilica-filled epoxy-resin composite coatings

    NASA Astrophysics Data System (ADS)

    Conradi, M.; Kocijan, A.; Kek-Merl, D.; Zorko, M.; Verpoest, I.

    2014-02-01

    Homogeneous, 50-μm-thick, epoxy coatings and composite epoxy coatings containing 2 wt% of 130-nm silica particles were successfully synthetized on austenitic stainless steel of the type AISI 316L. The surface morphology and mechanical properties of these coatings were compared and characterized using a profilometer, defining the average surface roughness and the Vickers hardness, respectively. The effects of incorporating the silica particles on the surface characteristics and the corrosion resistance of the epoxy-coated steel were additionally investigated with contact-angle measurements as well as by potentiodynamic polarization and electrochemical impedance spectroscopy in a 3.5 wt% NaCl solution. The silica particles were found to significantly improve the microstructure of the coating matrix, which was reflected in an increased hardness, increased surface roughness and induced hydrophobicity. Finally, the silica/epoxy coating was proven to serve as a successful barrier in a chloride-ion-rich environment with an enhanced anticorrosive performance, which was confirmed by the reduced corrosion rate and the increased coating resistance due to zigzagging of the diffusion path available to the ionic species.

  19. Micropatterning of a Bipolar Plate Using Direct Laser Melting Process

    SciTech Connect

    Jang, Jeong-hwan; Joo, Byeong-don; Mun, Sung-min; Moona, Young-hoon

    2010-06-15

    Direct laser melting (DLM) technology has been used to fabricate the micro-pattern of the bipolar plate in a direct methanol fuel cell (DMFC). A suitable approach to enhance the performance of the bipolar plate has been performed to optimize the DLM process. To fabricate the micro pattern, a DLM process with 316L stainless steel powder has been used. For the melted height of 1 mm, the DLM process conditions were optimized such as; laser power of 200 W, scan rate of 36.62 mm/s and the 8-layer structures. To characterize the effect of material type, the bipolar plates of various types were analyzed. In case of the 316L stainless steel DLM patterning, a current density of 297 mA/cm{sup 2} was achieved but the case of the 316L stainless steel plate, 248 mA/cm{sup 2} current density that is lower than that of other materials was achieved. The overall cell performance of 316L stainless steel DLM patterning bipolar plate was better than that of the 316L stainless steel plate. This has significant advantages for the micropatterning using DLM process. The use of 316L stainless steel powder material as micro pattern material will reduce the machining cost as well as volume of the fuel cell stack.

  20. Blood Typing

    MedlinePlus

    ... this page helpful? Also known as: Blood Group; Rh Factor Formal name: ABO Group and Rh Type Related ... mother's and baby's ABO blood groups, not the Rh factor. However, ABO grouping cannot be used to predict ...

  1. Initial observations of cavitation-induced erosion of liquid metal spallation target vessels at the Spallation Neutron Source

    SciTech Connect

    McClintock, David A; Riemer, Bernie; Ferguson, Phillip D; Carroll, Adam J; Dayton, Michael J

    2012-01-01

    During operation of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory the mechanical properties of the AISI 316L target module are altered by high-energy neutron and proton radiation. The interior surfaces of the target vessel are also damaged by cavitation-induced erosion, which results from repetitive rapid heating of the liquid mercury by high-energy proton beam pulses. Until recently no observations of cavitation-induced erosion were possible for conditions prototypical to the SNS. Post irradiation examination (PIE) of the first and second operational SNS targets was performed to gain insight into the radiation-induced changes in mechanical properties of the 316L target material and the extent of cavitation-induced erosion to the target vessel inner surfaces. Observations of cavitation-induced erosion of the first and second operational SNS target modules are presented here, including images of the target vessel interiors and specimens removed from the target beam-entrance regions.

  2. Evaluation of the stress corrosion behavior of selected stainless steels

    SciTech Connect

    Dorning, R.E. II

    1983-11-05

    The objective of this investigation was to determine the stress corrosion behavior of selected stainless steels in several fluorinating environments. The possibility of stress corrosion cracking or pitting which could substantially reduce the serviceability of the stainless steels was the primary concern. Laboratory testing indicated that stress corrosion cracking or other forms of localized attack of the austenitic stainless steels tested (304, 304-L, 316, and 316-L) would not occur in the dry gas environments investigated. AISI 316 and 316-L stainless steels exhibited no significant corrosion in any of the test environments. Stressed 304 and 304-L stainless steels exhibited increased general corrosion and pitting when moisture was added to the fluorinating environment. 3 refs., 1 fig., 3 tabs.

  3. Compatibility Assessment of Advanced Stainless Steels in Sodium

    SciTech Connect

    Pawel, Steven J

    2012-01-01

    Type 316L stainless steel capsules containing commercially pure sodium and miniature tensile specimens of HT-UPS (austenitic, 14Cr-16Ni), NF-616 (ferritic/martensitic, 9Cr-2W-0.5Mo), or 316L (austenitic, 17Cr-10Ni-2Mo) stainless steel were exposed at 600 or 700 C for 100 and 400 h as a screening test for compatibility. Using weight change, tensile testing, and metallographic analysis, HT-UPS and 316L were found to be largely immune to changes resulting from sodium exposure, but NF-616 was found susceptible to substantial decarburization at 700 C. Subsequently, two thermal convection loops (TCLs) constructed of 316L and loaded with commercially pure sodium and miniature tensile specimens of HT-UPS and 316L were operated for 2000 h each one between 500 and 650 C, the other between 565 and 725 C at a flow rate of about 1.5 cm/s. Changes in specimen appearance, weight, and tensile properties were observed to be very minor in all cases, and there was no metallographic evidence of microstructure changes, composition gradients, or mass transfer resulting from prolonged exposure in a TCL. Thus, it appears that HT-UPS and 316L stainless steels are similarly compatible with commercially pure sodium under these exposure conditions.

  4. Corrosion Performance of Stainless Steels in a Simulated Launch Environment

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Vinje, Rubiela D.; MacDowell, Louis

    2004-01-01

    At the Kennedy Space Center, NASA relies on stainless steel (SS) tubing to supply the gases and fluids required to launch the Space Shuttle. 300 series SS tubing has been used for decades but the highly corrosive environment at the launch pad has proven to be detrimental to these alloys. An upgrade with higher alloy content materials has become necessary in order to provide a safer and long lasting launch facility. In the effort to find the most suitable material to replace the existing AISI 304L SS ([iNS S30403) and AISI 316L SS (UNS S31603) shuttle tubing, a study involving atmospheric exposure at the corrosion test site near the launch pads and electrochemical measurements is being conducted. This paper presents the results of an investigation in which stainless steels of the 300 series, 304L, 316L, and AISI 317L SS (UNS S31703) as well as highly alloyed stainless steels 254-SMO (UNS S32154), AL-6XN (N08367) and AL29-4C ([iNS S44735) were evaluated using direct current (DC) electrochemical techniques under conditions designed to simulate those found at the Space Shuttle Launch pad. The electrochemical results were compared to the atmospheric exposure data and evaluated for their ability to predict the long-term corrosion performance of the alloys.

  5. Plastic deformation to enhance plasma-assisted nitriding: On surface contamination induced by Surface Mechanical Attrition Treatment

    NASA Astrophysics Data System (ADS)

    Samih, Youssef; Novelli, Marc; Thiriet, Tony; Bolle, Bernard; Allain, Nathalie; Fundenberger, Jean-Jacques; Marcos, Grégory; Czerwiec, Thierry; Grosdidier, Thierry

    2014-08-01

    The Surface Mechanical Attrition Treatment is a recent technique leading to the formation of nanostructured layers by the repeated action of impacting balls. While several communications have revealed possible contamination of the SMATed surfaces, the nature of this surface contamination was analyzed in the present contribution for the treatment of an AISI 316L stainless steel. It is shown, by a combination of Transmission Electron Microscopy and Glow Discharge - Optical Emission Spectrometry, that the surface was alloyed with Ti, Al and V coming from the sonotrode that is used to move the balls as well as Zr coming from the zirshot® balls themselves.

  6. In vitro electrochemical corrosion and cell viability studies on nickel-free stainless steel orthopedic implants.

    PubMed

    Salahinejad, Erfan; Hadianfard, Mohammad Jafar; Macdonald, Digby Donald; Sharifi-Asl, Samin; Mozafari, Masoud; Walker, Kenneth J; Rad, Armin Tahmasbi; Madihally, Sundararajan V; Tayebi, Lobat

    2013-01-01

    The corrosion and cell viability behaviors of nanostructured, nickel-free stainless steel implants were studied and compared with AISI 316L. The electrochemical studies were conducted by potentiodynamic polarization and electrochemical impedance spectroscopic measurements in a simulated body fluid. Cytocompatibility was also evaluated by the adhesion behavior of adult human stem cells on the surface of the samples. According to the results, the electrochemical behavior is affected by a compromise among the specimen's structural characteristics, comprising composition, density, and grain size. The cell viability is interpreted by considering the results of the electrochemical impedance spectroscopic experiments.

  7. In Vitro Electrochemical Corrosion and Cell Viability Studies on Nickel-Free Stainless Steel Orthopedic Implants

    PubMed Central

    Salahinejad, Erfan; Hadianfard, Mohammad Jafar; Macdonald, Digby Donald; Sharifi-Asl, Samin; Mozafari, Masoud; Walker, Kenneth J.; Rad, Armin Tahmasbi; Madihally, Sundararajan V.; Tayebi, Lobat

    2013-01-01

    The corrosion and cell viability behaviors of nanostructured, nickel-free stainless steel implants were studied and compared with AISI 316L. The electrochemical studies were conducted by potentiodynamic polarization and electrochemical impedance spectroscopic measurements in a simulated body fluid. Cytocompatibility was also evaluated by the adhesion behavior of adult human stem cells on the surface of the samples. According to the results, the electrochemical behavior is affected by a compromise among the specimen's structural characteristics, comprising composition, density, and grain size. The cell viability is interpreted by considering the results of the electrochemical impedance spectroscopic experiments. PMID:23630603

  8. Post-irradiation annealing effects of austenitic stainless steels in IASCC

    SciTech Connect

    Katsura, Ryoei; Ishiyama, Yoshihide; Yokota, Norikatu; Kato, Takahiko; Nakata, Kiyotomo; Fukuya, Kouji; Sakamoto, Hiroshi; Asano, Kyoichi

    1998-12-31

    Post-irradiation annealing effects on the thermal sensitization and IASCC recovery for highly irradiated types 304 and 316L stainless steels were investigated using EPR and SSR tests. Irradiated type 316L stainless steel (neutron fluence: 8 x 10{sup 25} n/m{sup 2}, E > 1 MeV) was not sensitized and IGSCC susceptibility significantly was reduced to 7--0% at 400--700 C (x1h) from 23% at as-irradiated condition. Irradiated type 304 stainless steel (neutron fluence: 1.2 x 10{sup 26} n/m{sup 2}, E > 1MeV) was more easily sensitized than unirradiated material and IGSCC susceptibility was reduced to 62--45% at 400--500 C from 95% at the as-irradiated condition. These results on types 304 and 316L stainless steels indicated that the thermal healing technic enhanced IASCC recovery.

  9. Field stress corrosion tests in brine environments of the Salton Sea known geothermal resource area

    SciTech Connect

    Carter, J.P.; Cramer, S.D.

    1980-01-01

    Corrosion research is being conducted to determine suitable construction materials for geothermal resource recovery plants. As part of this research, a 30-day stress corrosion test was conducted at the Salton Sea Known Geothermal Resource Area on seven iron- and nickel-base alloys in four brine and steam process streams using wellhead brine from geothermal well Magmamax 1. The tests showed transgranular cracking of AISI 316L stainless steel and intergranular and transgranular cracking of AISI 430 stainless steel in all four process streams. E-Brite 26-1 exhibited intergranular and transgranular cracking in three of the four process streams. Carbon steel, Inconel 625 and Hastelloys G and C-276 show no evidence of stress corrosion cracking.

  10. Assessment of the influence of surface finishing and weld joints on the corrosion/oxidation behaviour of stainless steels in lead bismuth eutectic

    NASA Astrophysics Data System (ADS)

    Martín-Muñoz, F. J.; Soler-Crespo, L.; Gómez-Briceño, D.

    2011-09-01

    The objective of this paper is to gain some insight into the influence of the surface finishing in the oxidation/corrosion behaviour of 316L and T91 steels in lead bismuth eutectic (LBE). Specimens of both materials with different surface states were prepared (as-received, grinded, grinded and polished, and electrolitically polished) and oxidation tests were carried out at 775 and 825 K from 100 to 2000 h for two different oxygen concentrations and for H 2/H 2O molar ratios of 3 and 0.03. The general conclusion for these tests is that the effect of surface finishing on the corrosion/protection processes is not significant under the tested conditions. In addition the behaviour of weld joints, T91-T91 Tungsten Inert Gas (TIG) and T91-316L have been also studied under similar conditions. The conclusions are that, whereas T91-T91 welded joint shows the same corrosion properties as the parent materials for the conditions tested, AISI 316L-T91 welded joint, present an important dissolution over seam area that it associated to the electrode 309S used for the fabrication process.

  11. AISI Direct Steelmaking Program. Final technical report

    SciTech Connect

    Aukrust, E.

    1994-08-01

    This final report deals with the results of a 5-yr project for developing a more energy-efficient, environmentally friendly, less costly process for producing hot metal than current coke ovens and blast furnaces. In the process, iron ore pellets are smelted in a foamy slag created by reaction of coal char with molten slag to produce CO. The CO further reacts with oxygen, which also reacts with coal volatile matter, to produce the heat necessary to sustain the endothermic reduction reaction. The uncombusted CO and H{sub 2} from the coal are used to preheat and prereduce hematite pellets for the most efficient use of the energy in the coal. Laboratory programs confirmed that the process steps worked. Pilot plant studies were successful. Economic analysis for a 1 million tpy plant is promising.

  12. Visualization of Hydrogen Diffusion in a Hydrogen-Enhanced Fatigue Crack Growth in Type 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Matsunaga, Hisao; Noda, Hiroshi

    2011-09-01

    To study the influence of hydrogen on the fatigue strength of AISI type 304 metastable austenitic stainless steel, specimens were cathodically charged with hydrogen. Using tension-compression fatigue tests, the behavior of fatigue crack growth from a small drill hole in the hydrogen-charged specimen was compared with that of noncharged specimen. Hydrogen charging led to a marked increase in the crack growth rate. Typical characteristics of hydrogen effect were observed in the slip band morphology and fatigue striation. To elucidate the behavior of hydrogen diffusion microscopically in the fatigue process, the hydrogen emission from the specimens was visualized using the hydrogen microprint technique (HMT). In the hydrogen-charged specimen, hydrogen emissions were mainly observed in the vicinity of the fatigue crack. Comparison between the HMT image and the etched microstructure image revealed that the slip bands worked as a pathway for hydrogen to move preferentially. Hydrogen-charging resulted in a significant change in the phase transformation behavior in the fatigue process. In the noncharged specimen, a massive type α' martensite was observed in the vicinity of the fatigue crack. On the other hand, in the hydrogen-charged specimen, large amounts of ɛ martensite and a smaller amount of α' martensite were observed along the slip bands. The results indicated that solute hydrogen facilitated the ɛ martensitic transformation in the fatigue process. Comparison between the results of HMT and EBSD inferred that martensitic transformations as well as plastic deformation itself can enhance the mobility of hydrogen.

  13. Bursts of Type III and Type V

    NASA Astrophysics Data System (ADS)

    Suzuki, S.; Dulk, G. A.

    The observational database on Types III and V solar radio bursts is summarized and used as a basis for developing analytical models of the observed phenomena. Type III events are characterized by a rapid drift from high to low frequencies, a harmonic structure consisting of F-H pairs, and circular polarization. Type V events last longer than Type III bursts and have a broader bandwidth. Both bursts are thought to arise from the same mechanism. Probable sources of the F-H pairs are characterized, along with the brightness temperature, time profiles, and polarization features typical of Type III and IIIb, structureless Type III and storm Type III bursts. Attention is also given to the interaction between Type III bursts and the coronal magnetic field and to similarities between Type III events and inverted-U and J bursts.

  14. Types of Breast Cancers

    MedlinePlus

    ... the key statistics about breast cancer? Types of breast cancers Breast cancer can be separated into different types ... than invasive ductal carcinoma. Less common types of breast cancer Inflammatory breast cancer This uncommon type of invasive ...

  15. Types of hormone therapy

    MedlinePlus

    ... types of hormone therapy; Hormone replacement therapy - types; Menopause - types of hormone therapy; HT - types; Menopausal hormone ... Menopause symptoms include: Hot flashes Night sweats Sleep problems Vaginal dryness Anxiety Moodiness Less interest in sex ...

  16. The effects of tritium and decay helium on the fracture toughness properties of stainless steels

    SciTech Connect

    Morgan, M.J.

    1991-01-01

    J-integral fracture mechanics techniques and scanning electron microscopy observations were used to investigate the effects of tritium and its decay product, helium-3, on Types 304L, 316L, 21-6-9, A286, and JBK-75 (Modified A286) stainless steels. Tritium-exposed samples of each steel had lower fracture toughness values and less resistance to stable crack growth than control samples. Type 316L stainless steel was more resistant to the embrittling effects of tritium and decay helium than the other steels.

  17. The effects of tritium and decay helium on the fracture toughness properties of stainless steels

    SciTech Connect

    Morgan, M.J.

    1991-12-31

    J-integral fracture mechanics techniques and scanning electron microscopy observations were used to investigate the effects of tritium and its decay product, helium-3, on Types 304L, 316L, 21-6-9, A286, and JBK-75 (Modified A286) stainless steels. Tritium-exposed samples of each steel had lower fracture toughness values and less resistance to stable crack growth than control samples. Type 316L stainless steel was more resistant to the embrittling effects of tritium and decay helium than the other steels.

  18. The effect of second-phase on the corrosion and wear behaviors of composite alloying layer

    NASA Astrophysics Data System (ADS)

    Xu, Jiang; Zhuo, Chenzhi; Tao, Jie; Jiang, Shuyun

    2008-12-01

    The present study concerns the effect of second-phase on the corrosion and wear behaviors of composite alloying layer, which is prepared by double glow plasma alloying of AISI316L steel with predeposited Ni/nano-SiC particle interlayer (by electric brush plating). The composition and microstructure of the composite alloying layer are analyzed by means of scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The results indicate that decomposition of nano-SiC particles have occurred under alloying temperature (1000 °C) condition and nano-SiC particles have reacted with Ni and Cr to form Cr 6.5Ni 2.5Si phase and Cr 23C 6 phase. The corrosion resistance of composite alloying layer was investigated by an electrochemical method in 3.5% NaCl and 5% HCl solution. The experimental results show that the corrosion resistance of the composite alloying layer is higher than that of AISI316L stainless steel and Ni/nano-SiC plating coating, but apparently lower than that of single alloying layer, which proves that the precipitated phase is harmful to the corrosion behavior of Ni-based alloying layer. The dry wear test results show that the composite alloying layer has excellent friction-reduced property, and relative wear resistance of composite alloying layer to Ni/nano-SiC plating coating, alloying layer and 316L stainless steel is 2.9, 3.6 and 5.3, respectively.

  19. Effect of Gas Tungsten Arc Welding Parameters on Hydrogen-Assisted Cracking of Type 321 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Rozenak, Paul; Unigovski, Yaakov; Shneck, Roni

    2016-05-01

    The susceptibility of AISI type 321 stainless steel welded by the gas tungsten arc welding (GTAW) process to hydrogen-assisted cracking (HAC) was studied in a tensile test combined with in situ cathodic charging. Specimen charging causes a decrease in ductility of both the as-received and welded specimens. The mechanical properties of welds depend on welding parameters. For example, the ultimate tensile strength and ductility increase with growing shielding gas (argon) rate. More severe decrease in the ductility was obtained after post-weld heat treatment (PWHT). In welded steels, in addition to discontinuous grain boundary carbides (M23C6) and dense distribution of metal carbides MC ((Ti, Nb)C) precipitated in the matrix, the appearance of delta-ferrite phase was observed. The fracture of sensitized specimens was predominantly intergranular, whereas the as-welded specimens exhibited mainly transgranular regions. High-dislocation density regions and stacking faults were found in delta-ferrite formed after welding. Besides, thin stacking fault plates and epsilon-martensite were found in the austenitic matrix after the cathodic charging.

  20. Types of Diabetes

    MedlinePlus

    Skip Navigation Bar Home Current Issue Past Issues Types of Diabetes Past Issues / Fall 2006 Table of Contents For ... version of this page please turn Javascript on. Type 1 Diabetes Type 1 diabetes, formerly called juvenile diabetes or ...

  1. Ion beam nitriding of single and polycrystalline austenitic stainless steel

    SciTech Connect

    Abrasonis, G.; Riviere, J.P.; Templier, C.; Declemy, A.; Pranevicius, L.; Milhet, X.

    2005-04-15

    Polycrystalline and single crystalline [orientations (001) and (011)] AISI 316L austenitic stainless steel was implanted at 400 deg. C with 1.2 keV nitrogen ions using a high current density of 0.5 mA cm{sup -2}. The nitrogen distribution profiles were determined using nuclear reaction analysis (NRA). The structure of nitrided polycrystalline stainless steel samples was analyzed using glancing incidence and symmetric x-ray diffraction (XRD) while the structure of the nitrided single crystalline stainless steel samples was analyzed using x-ray diffraction mapping of the reciprocal space. For identical treatment conditions, it is observed that the nitrogen penetration depth is larger for the polycrystalline samples than for the single crystalline ones. The nitrogen penetration depth depends on the orientation, the <001> being more preferential for nitrogen diffusion than <011>. In both type of samples, XRD analysis shows the presence of the phase usually called 'expanded' austenite or {gamma}{sub N} phase. The lattice expansion depends on the crystallographic plane family, the (001) planes showing an anomalously large expansion. The reciprocal lattice maps of the nitrided single crystalline stainless steel demonstrate that during nitriding lattice rotation takes place simultaneously with lattice expansion. The analysis of the results based on the presence of stacking faults, residual compressive stress induced by the lattice expansion, and nitrogen concentration gradient indicates that the average lattice parameter increases with the nitrided layer depth. A possible explanation of the anomalous expansion of the (001) planes is presented, which is based on the combination of faster nitriding rate in the (001) oriented grains and the role of stacking faults and compressive stress.

  2. Petrov type of linearly perturbed type-D spacetimes

    NASA Astrophysics Data System (ADS)

    Araneda, Bernardo; Dotti, Gustavo

    2015-10-01

    We show that a spacetime satisfying the linearized vacuum Einstein equations around a type-D background is generically of type I, and that the splittings of the principal null directions (PNDs) and of the degenerate eigenvalue of the Weyl tensor are non-analytic functions of the perturbation parameter of the metric. This provides a gauge-invariant characterization of the effect of the perturbation on the underlying geometry, without appealing to differential curvature invariants. This is of particular interest for the Schwarzschild solution, for which there are no signatures of the even perturbations on the algebraic curvature invariants. We also show that, unlike the general case, the unstable even modes of the Schwarzschild naked singularity deform the Weyl tensor into a type-II one.

  3. Moving beyond Type I and Type II neuron types.

    PubMed

    Skinner, Frances K

    2013-01-01

    In 1948, Hodgkin delineated different classes of axonal firing.  This has been mathematically translated allowing insight and understanding to emerge.  As such, the terminology of 'Type I' and 'Type II' neurons is commonplace in the Neuroscience literature today.  Theoretical insights have helped us realize that, for example, network synchronization depends on whether neurons are Type I or Type II.  Mathematical models are precise with analyses (considering Type I/II aspects), but experimentally, the distinction can be less clear.  On the other hand, experiments are becoming more sophisticated in terms of distinguishing and manipulating particular cell types but are limited in terms of being able to consider network aspects simultaneously.   Although there is much work going on mathematically and experimentally, in my opinion it is becoming common that models are either superficially linked with experiment or not described in enough detail to appreciate the biological context.  Overall, we all suffer in terms of impeding our understanding of brain networks and applying our understanding to neurological disease.  I suggest that more modelers become familiar with experimental details and that more experimentalists appreciate modeling assumptions. In other words, we need to move beyond our comfort zones.

  4. Custodial Teacher Social Types.

    ERIC Educational Resources Information Center

    Licata, Joseph W.

    Two types of teacher behavior were elicited from student responses to the Pupil Control Behavior Form (PCB). Two custodial teacher types emerged from the data: the "screamer" type, described as a teacher who controlled pupil behavior with verbal methods that expressed anger or frustration; and the "cold fish" type, depicted as a teacher who…

  5. Stress Corrosion Cracking—Crevice Interaction in Austenitic Stainless Steels Characterized By Acoustic Emission

    NASA Astrophysics Data System (ADS)

    Leinonen, H.; Schildt, T.; Hänninen, H.

    2011-02-01

    Stress corrosion cracking (SCC) susceptibility of austenitic EN1.4301 (AISI 304) and EN1.4404 (AISI 316L) stainless steels was studied using the constant load method and polymer (PTFE) crevice former in order to study the effects of crevice on SCC susceptibility. The uniaxial active loading tests were performed in 50 pct CaCl2 at 373 K (100 °C) and in 0.1 M NaCl at 353 K (80 °C) under open-circuit corrosion potential (OCP) and electrochemical polarization. Pitting, crevice, and SCC corrosion were characterized and identified by acoustic emission (AE) analysis using ∆ t filtering and the linear locationing technique. The correlation of AE parameters including amplitude, duration, rise time, counts, and energy were used to identify the different types of corrosion. The stages of crevice corrosion and SCC induced by constant active load/crevice former were monitored by AE. In the early phase of the tests, some low amplitude AE activity was detected. In the steady-state phase, the AE activity was low, and toward the end of the test, it increased with the increasing amplitude of the impulses. AE allowed a good correlation between AE signals and corrosion damage. Although crevice corrosion and SCC induced AE signals overlapped slightly, a good correlation between them and microscopical characterization and stress-strain data was found. Especially, the activity of AE signals increased in the early and final stages of the SCC experiment under constant active load conditions corresponding to the changes in the measured steady-state creep strain rate of the specimen. The results of the constant active load/crevice former test indicate that a crevice can initiate SCC even in the mild chloride solution at low temperatures. Based on the mechanistic model of SCC, the rate determining step in SCC is thought to be the generation of vacancies by selective dissolution, which is supported by the low activity phase of AE during the steady-state creep strain rate region.

  6. Types of Hemolytic Anemia

    MedlinePlus

    ... from the NHLBI on Twitter. Types of Hemolytic Anemia There are many types of hemolytic anemia. The ... the condition, but you develop it. Inherited Hemolytic Anemias With inherited hemolytic anemias, one or more of ...

  7. [Types of biofeedback].

    PubMed

    Kubik, Paweł

    2016-01-01

    The author presented 9 types of biofeedback witch are usefull in medical practice. He explained neurophysiological circuits involved in this process. He presented technical basis of the different types of biofeedback and pathological fields of its supplementation. PMID:27349053

  8. Unlocking Personality Type.

    ERIC Educational Resources Information Center

    Tieger, Paul D.

    2002-01-01

    This article examines some of the intricacies of personality types and their effect on career choices. Proposes that knowing students' Myers-Briggs personality types can help school counselors guide them down the right career path. (GCP)

  9. Blood Type Puzzle.

    ERIC Educational Resources Information Center

    Kelly, Janet

    1997-01-01

    Presents a blood type puzzle that provides a visual, hands-on mechanism by which students can examine blood group reactions. Offers students an opportunity to construct their own knowledge about blood types. (JRH)

  10. Acoustic Emission Technique for Characterizing Deformation and Fatigue Crack Growth in Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Raj, Baldev; Mukhopadhyay, C. K.; Jayakumar, T.

    2003-03-01

    Acoustic emission (AE) during tensile deformation and fatigue crack growth (FCG) of austenitic stainless steels has been studied. In AISI type 316 stainless steel (SS), AE has been used to detect micro plastic yielding occurring during macroscopic plastic deformation. In AISI type 304 SS, relation of AE with stress intensity factor and plastic zone size has been studied. In AISI type 316 SS, fatigue crack growth has been characterised using acoustic emission.

  11. Type Has Many Faces.

    ERIC Educational Resources Information Center

    Turner, Ralph J.

    1996-01-01

    Affirms that taking time to learn type classification, terminology, and use will be a major step in producing more effective high school newspapers. Considers that desktop publishing is both a blessing and a curse when it comes to type use. Provides type use definitions. (PA)

  12. Diabetes Type 2

    MedlinePlus

    Diabetes means your blood glucose, or blood sugar, levels are too high. With type 2 diabetes, the more common type, your body does not ... You have a higher risk of type 2 diabetes if you are older, obese, have a family ...

  13. Types of Data Systems

    ERIC Educational Resources Information Center

    Gould, Tate; Nicholas, Amy; Ruggiero, Tony; Blandford, William; Thayer, Sara; Bull, Bruce

    2015-01-01

    There are several types of data systems that support data from Part C/619 programs. Although the system types have similarities, each has its own unique characteristics and purposes. The attributes that make one type of data system a particularly good fit for one data-related need or function can be less desirable for another need or function. In…

  14. Fun with Type Functions

    NASA Astrophysics Data System (ADS)

    Kiselyov, Oleg; Jones, Simon Peyton; Shan, Chung-Chieh

    Tony Hoare has always been a leader in writing down and proving properties of programs. To prove properties of programs automatically, the most widely used technology today is the ubiquitous type checker. Alas, static type systems inevitably exclude some good programs and allow some bad ones. Thus motivated, we describe some fun we have been having with Haskell, by making the type system more expressive without losing the benefits of automatic proof and compact expression. Specifically, we offer a programmer's tour of so-calledtype families, a recent extension to Haskell that allows functions on types to be expressed as straightforwardly as functions on values. This facility makes it easier for programmers to effectively extend the compiler by writing functional programs that execute during type checking. Source code for all the examples is available at http://research.microsoft.com/simonpj/papers/assoc-types/fun-with-type-funs.zip.

  15. Interactions between Child Types and Classroom Types.

    ERIC Educational Resources Information Center

    Solomon, Daniel; Kendall, Arthur J.

    Research is described which explores the hypothesis that different classroom situations may be optimal for different individuals. The approach used cluster analysis to identify student and classroom "types" whose interactions were then examined in an analysis of variance framework. About 1,300 fourth graders from 50 classrooms were involved in the…

  16. Typing Manuscripts and Reports. Typing 13.

    ERIC Educational Resources Information Center

    Nederland Independent School District, TX.

    GRADES OR AGES: Grade 13. SUBJECT MATTER: Typing manuscripts and reports. ORGANIZATION AND PHYSICAL APPEARANCE: The introductory material contains general instructions on spacing, margins, and paging. The main text contains 32 manuscripts which are varied according to arrangement and length. The guide is lithographed and spiral bound with a soft…

  17. Types of Neutralization and Types of Delinquency.

    ERIC Educational Resources Information Center

    Mitchell, Jim; Dodder, Richard A.

    1983-01-01

    Neutralization theory was tested with questionnaires administered to a random sample of public high school students (N-298) and institutionalized male delinquents (N-53). Neutralization acceptance technique patterns were similar across subsamples; however, correlations between each technique and each type of delinquency were statistically…

  18. Accumulation of radioactive corrosion products on steel surfaces of VVER type nuclear reactors. I. 110mAg

    NASA Astrophysics Data System (ADS)

    Hirschberg, Gábor; Baradlai, Pál; Varga, Kálmán; Myburg, Gerrit; Schunk, János; Tilky, Péter; Stoddart, Paul

    Formation, presence and deposition of corrosion product radionuclides (such as 60Co, 51Cr, 54Mn, 59Fe and/or 110mAg) in the primary circuits of water-cooled nuclear reactors (PWRs) throw many obstacles in the way of normal operation. During the course of the work presented in this series, accumulations of such radionuclides have been studied at austenitic stainless steel type 08X18H10T (GOST 5632-61) surfaces (this austenitic stainless steel corresponds to AISI 321). Comparative experiments have been performed on magnetite-covered carbon steel (both materials are frequently used in some Soviet VVER type PWRs). For these laboratory-scale investigations a combination of the in situ radiotracer `thin gap' method and voltammetry is considered to be a powerful tool due to its high sensitivity towards the detection of the submonolayer coverages of corrosion product radionuclides. An independent technique (XPS) is also used to characterize the depth distribution and chemical state of various contaminants in the passive layer formed on austenitic stainless steel. In the first part of the series the accumulation of 110mAg has been investigated. Potential dependent sorption of Ag + ions (cementation) is found to be the predominant process on austenitic steel, while in the case of magnetite-covered carbon steel the silver species are mainly depleted in the form of Ag 2O. The XPS depth profile of Ag gives an evidence about the embedding of metallic silver into the entire passive layer of the austenitic stainless steel studied.

  19. Type II universal spacetimes

    NASA Astrophysics Data System (ADS)

    Hervik, S.; Málek, T.; Pravda, V.; Pravdová, A.

    2015-12-01

    We study type II universal metrics of the Lorentzian signature. These metrics simultaneously solve vacuum field equations of all theories of gravitation with the Lagrangian being a polynomial curvature invariant constructed from the metric, the Riemann tensor and its covariant derivatives of an arbitrary order. We provide examples of type II universal metrics for all composite number dimensions. On the other hand, we have no examples for prime number dimensions and we prove the non-existence of type II universal spacetimes in five dimensions. We also present type II vacuum solutions of selected classes of gravitational theories, such as Lovelock, quadratic and L({{Riemann}}) gravities.

  20. Giftedness and Psychological Type.

    ERIC Educational Resources Information Center

    Hawkins, John

    1998-01-01

    Comparison of the psychological types, as measured by the Myers-Briggs Type Indicator (MBTI), of 966 students at a public residential magnet high school for academically talented students with other gifted and traditional high school students found both magnet school students and gifted students showed a particular MBTI distribution. (DB)