Sample records for modeling 304l stainless

  1. Anomalous Annealing Response of Directed Energy Deposited Type 304L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Smith, Thale R.; Sugar, Joshua D.; Schoenung, Julie M.; San Marchi, Chris

    2018-03-01

    Directed energy deposited (DED) and forged austenitic stainless steels possess dissimilar microstructures but can exhibit similar mechanical properties. In this study, annealing was used to evolve the microstructure of both conventional wrought and DED type 304L austenitic stainless steels, and significant differences were observed. In particular, the density of geometrically necessary dislocations and hardness were used to probe the evolution of the microstructure and properties. Forged type 304L exhibited the expected decrease in measured dislocation density and hardness as a function of annealing temperature. The more complex microstructure-property relationship observed in the DED type 304L material is attributed to compositional heterogeneities in the solidification microstructure.

  2. Long-Term Effects of Temperature Exposure on SLM 304L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Amine, Tarak; Kriewall, Caitlin S.; Newkirk, Joseph W.

    2018-03-01

    Austenitic stainless steel is extensively used in industries that operate at elevated temperatures. This work investigates the high-temperature microstructure stability as well as elevated-temperature properties of 304L stainless steel fabricated using the selective laser melting (SLM) process. Significant microstructural changes were seen after a 400°C aging process for as little as 25 h. This dramatic change in microstructure would not be expected based on the ferrite decomposition studied in conventional 304L materials. The as-built additively manufactured alloy has much faster kinetic response to heat treatment at 400°C. An investigation of the structures which occur, the kinetics of the various transformations, and the mechanical properties is presented. The impact of this on the application of SLM 304L is discussed.

  3. Laser Rewelding of 304L Stainless Steel.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maguire, Michael Christopher; Rodelas, Jeffrey

    Laser welding of 304L stainless steel during component fabrication has been found to alter the chemical composition of the steel due to material evaporation. During repair or rework, or during potential reuse/ rewelding of certain components, the potential exists to alter the composition to the extent that the material becomes prone to solidification cracking. This work aims to characterize the extent of this susceptibility in order to make informed decisions regarding rewelding practice and base metal chemistry allowances.

  4. Numerical Simulation and Artificial Neural Network Modeling for Predicting Welding-Induced Distortion in Butt-Welded 304L Stainless Steel Plates

    NASA Astrophysics Data System (ADS)

    Narayanareddy, V. V.; Chandrasekhar, N.; Vasudevan, M.; Muthukumaran, S.; Vasantharaja, P.

    2016-02-01

    In the present study, artificial neural network modeling has been employed for predicting welding-induced angular distortions in autogenous butt-welded 304L stainless steel plates. The input data for the neural network have been obtained from a series of three-dimensional finite element simulations of TIG welding for a wide range of plate dimensions. Thermo-elasto-plastic analysis was carried out for 304L stainless steel plates during autogenous TIG welding employing double ellipsoidal heat source. The simulated thermal cycles were validated by measuring thermal cycles using thermocouples at predetermined positions, and the simulated distortion values were validated by measuring distortion using vertical height gauge for three cases. There was a good agreement between the model predictions and the measured values. Then, a multilayer feed-forward back propagation neural network has been developed using the numerically simulated data. Artificial neural network model developed in the present study predicted the angular distortion accurately.

  5. Quasi-Isentropic Compression of Wrought and Additively Manufactures 304L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Specht, Paul; Brown, Justin; Wise, Jack; Furnish, Michael; Adams, David

    2017-06-01

    The thermodynamic and constitutive responses of both additively manufactured (AM) and traditional wrought processed 304L stainless steel (SS) were investigated through quasi-isentropic compression to peak stresses near 1Mbar using Sandia National Laboratories' Z machine. The AM 304L SS samples were made with a laser engineered net shaping (LENS™) technique. Compared to traditional wrought processed 304L SS, the AM samples were highly textured with larger grain sizes (i.e.near 1mm) and residual stresses (> 100 MPa). Interferometric measurements of interface velocities enabled inference of the quasi-isentropes for each fabrication type of 304L SS. Release from peak stress provided flow strength measurements of the wrought and AM 304L SS. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Approved For Unclassified Unlimited Release SAND2017-2040A.

  6. Effect of Temperature on the Fracture Toughness of Hot Isostatically Pressed 304L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Cooper, A. J.; Brayshaw, W. J.; Sherry, A. H.

    2018-03-01

    Herein, we have performed J- Resistance multi-specimen fracture toughness testing of hot isostatically pressed (HIP'd) and forged 304L austenitic stainless steel, tested at elevated (300 °C) and cryogenic (- 140 °C) temperatures. The work highlights that although both materials fail in a pure ductile fashion, stainless steel manufactured by HIP displays a marked reduction in fracture toughness, defined using J 0.2BL, when compared to equivalently graded forged 304L, which is relatively constant across the tested temperature range.

  7. Modeling Periodic Adiabatic Shear Bands Evolution in a 304L Stainless Steel Thick-Walled Cylinder

    NASA Astrophysics Data System (ADS)

    Liu, Mingtao; Hu, Haibo; Fan, Cheng; Tang, Tiegang

    2015-06-01

    The self-organization of multiple shear bands in a 304L stainless steel thick-walled cylinder (TWC) was numerically studied. The microstructures of material lead to the non-uniform distribution of local yield stress, which plays a key role in the formation of spontaneous shear localization. We introduced a probability factor satisfied Gauss distribution into the macroscopic constitutive relationship to describe the non-uniformity of local yield stress. Using the probability factor, the initiation and propagation of multiple shear bands in TWC were numerically replicated in our 2D FEM simulation. Experimental results in the literature indicate that the machined surface at the internal boundary of a 304L stainless steel cylinder provides a work-hardened layer (about 20 μm) which has significantly different microstructures from base material. The work-hardened layer leads to the phenomenon that most shear bands are in clockwise or counterclockwise direction. In our simulation, periodic oriented perturbations were applied to describe the grain orientation in the work-hardened layer, and the spiral pattern of shear bands was successfully replicated.

  8. Experimental Investigation of Friction and Wear Behavior of 304L Stainless Steel Sliding Against Different Counterface in Dry Contact

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Olofinjana, Bolutife; Ajayi, Oyelayo O.; Lorenzo-Martin, Cinta

    In this study, friction and wear behavior of 304L stainless steel sliding against different ball counterface under dry contact was investigated. Tests were conducted using a ball-on-flat contact configuration in reciprocating sliding with 440C stainless steel, Al alloy (2017) and bronze ball counterfaces under different loads. Detailed surface analysis was also done using 3-D profilometry technique and optical microscopy in order to determine wear mechanism and dimension. All the pairs exhibited initial rapid increase in coefficient of friction after which a variety of friction behavior, depending on the ball counterface, was observed. The flat and the ball counterface in 304Lmore » stainless steel-440C stainless steel pair showed wear that was proportional to applied load. In both 304L stainless steel-Al alloy (2017) and 304L stainless steel-bronze pairs, ball samples showed severe wear that was proportional to the applied load while material transfer from the different balls occurred in the flat. The study concluded that friction and wear were not material properties but a kind of responses that characterize a pair of surfaces in contact undergoing relative motion.« less

  9. An Assessment of the Ductile Fracture Behavior of Hot Isostatically Pressed and Forged 304L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Cooper, A. J.; Smith, R. J.; Sherry, A. H.

    2017-05-01

    Type 300 austenitic stainless steel manufactured by hot isostatic pressing (HIP) has recently been shown to exhibit subtly different fracture behavior from that of equivalent graded forged steel, whereby the oxygen remaining in the component after HIP manifests itself in the austenite matrix as nonmetallic oxide inclusions. These inclusions facilitate fracture by acting as nucleation sites for the initiation, growth, and coalescence of microvoids in the plastically deforming austenite matrix. Here, we perform analyses based on the Rice-Tracey (RT) void growth model, supported by instrumented Charpy and J-integral fracture toughness testing at ambient temperature, to characterize the degree of void growth ahead of both a V-notch and crack in 304L stainless steel. We show that the hot isostatically pressed (HIP'd) 304L steel exhibits a lower critical void growth at the onset of fracture than that observed in forged 304L steel, which ultimately results in HIP'd steel exhibiting lower fracture toughness at initiation and impact toughness. Although the reduction in toughness of HIP'd steel is not detrimental to its use, due to the steel's sufficiently high toughness, the study does indicate that HIP'd and forged 304L steel behave as subtly different materials at a microstructural level with respect to their fracture behavior.

  10. Temperature effects on the mechanical properties of annealed and HERF 304L stainless steel.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Antoun, Bonnie R.

    2004-11-01

    The effect of temperature on the tensile properties of annealed 304L stainless steel and HERF 304L stainless steel forgings was determined by completing experiments over the moderate range of -40 F to 160 F. Temperature effects were more significant in the annealed material than the HERF material. The tensile yield strength of the annealed material at -40 F averaged twenty two percent above the room temperature value and at 160 F averaged thirteen percent below. The tensile yield strength for the three different geometry HERF forgings at -40 F and 160 F changed less than ten percent from room temperature.more » The ultimate tensile strength was more temperature dependent than the yield strength. The annealed material averaged thirty six percent above and fourteen percent below the room temperature ultimate strength at -40 F and 160 F, respectively. The HERF forgings exhibited similar, slightly lower changes in ultimate strength with temperature. For completeness and illustrative purposes, the stress-strain curves are included for each of the tensile experiments conducted. The results of this study prompted a continuation study to determine tensile property changes of welded 304L stainless steel material with temperature, documented separately.« less

  11. 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.

  12. Abnormal grain growth in AISI 304L stainless steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shirdel, M., E-mail: mshirdel1989@ut.ac.ir; Mirzadeh, H., E-mail: hmirzadeh@ut.ac.ir; Advanced Metalforming and Thermomechanical Processing Laboratory, School of Metallurgy and Materials Engineering, University of Tehran, Tehran

    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 dispersivemore » 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.« less

  13. Compressibility of 304 Stainless Steel Powder Metallurgy Materials Reinforced with 304 Short Stainless Steel Fibers

    PubMed Central

    Yao, Bibo; Zhou, Zhaoyao; Duan, Liuyang; Xiao, Zhiyu

    2016-01-01

    Powder metallurgy (P/M) technique is usually used for manufacturing porous metal materials. However, some P/M materials are limitedly used in engineering for their performance deficiency. A novel 304 stainless steel P/M material was produced by a solid-state sintering of 304 stainless steel powders and 304 short stainless steel fibers, which were alternately laid in layers according to mass ratio. In this paper, the compressive properties of the P/M materials were characterized by a series of uniaxial compression tests. The effects of fiber content, compaction pressure and high temperature nitriding on compressive properties were investigated. The results indicated that, without nitriding, the samples changed from cuboid to cydariform without damage in the process of compression. The compressive stress was enhanced with increasing fiber content ranging from 0 to 8 wt.%. For compaction pressure from 55 to 75 MPa, greater compaction pressure improved compressive stress. Moreover, high temperature nitriding was able to significantly improve the yield stress, but collapse failure eventually occurred. PMID:28773285

  14. Compressibility of 304 Stainless Steel Powder Metallurgy Materials Reinforced with 304 Short Stainless Steel Fibers.

    PubMed

    Yao, Bibo; Zhou, Zhaoyao; Duan, Liuyang; Xiao, Zhiyu

    2016-03-04

    Powder metallurgy (P/M) technique is usually used for manufacturing porous metal materials. However, some P/M materials are limitedly used in engineering for their performance deficiency. A novel 304 stainless steel P/M material was produced by a solid-state sintering of 304 stainless steel powders and 304 short stainless steel fibers, which were alternately laid in layers according to mass ratio. In this paper, the compressive properties of the P/M materials were characterized by a series of uniaxial compression tests. The effects of fiber content, compaction pressure and high temperature nitriding on compressive properties were investigated. The results indicated that, without nitriding, the samples changed from cuboid to cydariform without damage in the process of compression. The compressive stress was enhanced with increasing fiber content ranging from 0 to 8 wt.%. For compaction pressure from 55 to 75 MPa, greater compaction pressure improved compressive stress. Moreover, high temperature nitriding was able to significantly improve the yield stress, but collapse failure eventually occurred.

  15. Kinetics of Pseudomonas aeruginosa adhesion to 304 and 316-L stainless steel: role of cell surface hydrophobicity.

    PubMed Central

    Vanhaecke, E; Remon, J P; Moors, M; Raes, F; De Rudder, D; Van Peteghem, A

    1990-01-01

    Fifteen different isolates of Pseudomonas aeruginosa were used to study the kinetics of adhesion to 304 and 316-L stainless steel. Stainless steel plates were incubated with approximately 1.5 X 10(7) CFU/ml in 0.01 M phosphate-buffered saline (pH 7.4). After the plates were rinsed with the buffer, the number of adhering bacteria was determined by a bioluminescence assay. Measurable adhesion, even to the electropolished surfaces, occurred within 30 s. Bacterial cell surface hydrophobicity, as determined by the bacterial adherence to hydrocarbons test and the contact angle measurement test, was the major parameter influencing the adhesion rate constant for the first 30 min of adhesion. A parabolic relationship between the CAM values and the logarithm of the adhesion rate constants (In k) was established. No correlation between either the salt aggregation or the improved salt aggregation values and the bacterial adhesion rate constants could be found. Since there was no significant correlation between the bacterial electrophoretic mobilities and the In k values, the bacterial cell surface charge seemed of minor importance in the process of adhesion of P. aeruginosa to 304 and 316-L stainless steel. PMID:2107796

  16. Refinement of the magnetic composite model of type 304 stainless steel by considering misoriented ferromagnetic martensite particles

    NASA Astrophysics Data System (ADS)

    Kinoshita, Katsuyuki

    2017-05-01

    We improved a magnetic composite model that combines the Jiles-Atherton model and Eshelby's equivalent inclusion method to consider misoriented martensite particles. The magnetic permeability of type 304 stainless steel were analyzed by using both experimental data on the orientation distribution of type 304 stainless steel specimens and the improved model. We found that the model is able to qualitatively explain the variation of permeability with the orientation angle and orientation distribution, an effect that depends on the direction of the excitation magnetic field.

  17. Comparative shock response of additively manufactured versus conventionally wrought 304L stainless steel

    NASA Astrophysics Data System (ADS)

    Wise, J. L.; Adams, D. P.; Nishida, E. E.; Song, B.; Maguire, M. C.; Carroll, J.; Reedlunn, B.; Bishop, J. E.; Palmer, T. A.

    2017-01-01

    Gas-gun experiments have probed the compression and release behavior of impact-loaded 304L stainless steel specimens that were machined from additively manufactured (AM) blocks as well as baseline ingot-derived bar stock. The AM technology permits direct fabrication of net- or near-net-shape metal parts. For the present investigation, velocity interferometer (VISAR) diagnostics provided time-resolved measurements of sample response for one-dimensional (i.e., uniaxial strain) shock compression to peak stresses ranging from 0.2 to 7.0 GPa. The acquired wave-profile data have been analyzed to determine the comparative Hugoniot Elastic Limit (HEL), Hugoniot equation of state, spall strength, and high-pressure yield strength of the AM and conventional materials. The possible contributions of various factors, such as composition, porosity, microstructure (e.g., grain size and morphology), residual stress, and/or sample axis orientation relative to the additive manufacturing deposition trajectory, are considered to explain differences between the AM and baseline 304L dynamic material results.

  18. Comparative Shock Response of Additively Manufactured Versus Conventionally Wrought 304L Stainless Steel*

    NASA Astrophysics Data System (ADS)

    Wise, J. L.; Adams, D. P.; Nishida, E. E.; Song, B.; Maguire, M. C.; Carroll, J.; Reedlunn, B.; Bishop, J. E.

    2015-06-01

    Gas-gun experiments have probed the compression and release behavior of impact-loaded 304L stainless steel specimens machined from additively manufactured (AM) blocks as well as baseline ingot-derived bar stock. The AM technology allows direct fabrication of metal parts. For the present study, a velocity interferometer (VISAR) measured the time-resolved motion of samples subjected to one-dimensional (i.e., uniaxial strain) shock compression to peak stresses ranging from 0.2 to 7.5 GPa. The acquired wave-profile data have been analyzed to determine the comparative Hugoniot Elastic Limit (HEL), Hugoniot equation of state, spall strength, and high-pressure yield strength of the AM and conventional materials. Observed differences in shock loading and unloading characteristics for the two 304L source variants have been correlated to complementary Kolsky bar results for compressive and tensile testing at lower strain rates. The effects of composition, porosity, microstructure (e.g., grain size and morphology), residual stress, and sample axis orientation relative to the additive manufacturing deposition trajectory have been assessed to explain differences between the AM and baseline 304L dynamic mechanical properties. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  19. GTA weld cracking-alloy 625 to 304L

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Patterson, R.A.; Milewski, J.O.

    1985-08-01

    Autogenous gas tungsten arc welds joining alloy 625 and 304L stainless steel were found to be susceptible to weld solidification cracking. Utilization of pulsed current GTA welding produced a higher sensitivity to solidification cracks than continuous current welding. Spot Varestraint tests show that the sensitivity of this dissimilar metal combination to cracking exists over the entire range of dilutions while the greatest sensitivity is in 304L stainless steel rich compositions. Auger electron spectroscopy indicates that segregation of sulfur and phosphorous to the interdendritic phase promotes the hot cracking.

  20. Warm Pre-Strain: Strengthening the Metastable 304L Austenitic Stainless Steel without Compromising Its Hydrogen Embrittlement Resistance

    PubMed Central

    Wang, Yanfei; Zhou, Zhiling; Wu, Weijie; Gong, Jianming

    2017-01-01

    Plastic pre-strains were applied to the metastable 304L austenitic stainless steel at both room temperature (20 °C) and higher temperatures (i.e., 50, 80 and 100 °C), and then the hydrogen embrittlement (HE) susceptibility of the steel was evaluated by cathodically hydrogen-charging and tensile testing. The 20 °C pre-strain greatly strengthened the steel, but simultaneously significantly increased the HE susceptibility of the steel, since α′ martensite was induced by the pre-strain, causing the pre-existence of α′ martensite, which provided “highways” for hydrogen to transport deep into the steel during the hydrogen-charging. Although the warm pre-strains did not strengthen the steel as significantly as the 20 °C pre-strain, they retained the HE resistance of the steel. This is because the higher temperatures, particularly 80 and 100 °C, suppressed the α′ martensite transformation during the pre-straining. Pre-strain at a temperature slightly higher than room temperature has a potential to strengthen the metastable 304L austenitic stainless steel without compromising its initial HE resistance. PMID:29160830

  1. Effect of SiC particle impact nano-texturing on tribological performance of 304L stainless steel

    NASA Astrophysics Data System (ADS)

    Lorenzo-Martin, C.; Ajayi, O. O.

    2014-10-01

    Topographical features on sliding contact surfaces are known to have a significant impact on friction and wear. Indeed, various forms of surface texturing are being used to improve and/or control the tribological performance of sliding surfaces. In this paper, the effect of random surface texturing produced by a mechanical impact process is studied for friction and wear behavior of 304L stainless steel (SS) under dry and marginal oil lubrication. The surface processing was applied to 304L SS flat specimens and tested under reciprocating ball-on-flat sliding contact, with a 440C stainless steel ball. Under dry contact, the impact textured surface exhibited two order of magnitude lower wear than the isotropically ground surface of the same material. After 1500 s of sliding and wearing through of the processed surface layer following occurring of scuffing, the impact textured surface underwent a transition in wear and friction behavior. Under marginal oil lubrication, however, no such transition occurred, and the wear for the impact textured surface was consistently two orders of magnitude lower than that for the ground material. Mechanisms for the tribological performance enhancement are proposed.

  2. Phase transition of AISI type 304L stainless steel induced by severe plastic deformation via cryo-rolling

    NASA Astrophysics Data System (ADS)

    Shit, Gopinath; Bhaskar, Pragna; Ningshen, S.; Dasgupta, A.; Mudali, U. Kamachi; Bhaduri, A. Kumar

    2017-05-01

    The phase transition induced by Severe Plastic Deformation (SPD) was confirmed in metastable AISI type 304L austenitic stainless steel (SS). SPD via cryo-rolling in liquid nitrogen (L-N2) temperature is the adopted route for correlating the phase transition and corrosion resistance. The thickness of the annealed AISI type 304L SS at 1050°C sheet was reduced step by step from 15% to 50% of its initial thickness. The phase changes and phase transformation are qualitatively analyzed by X-Ray Diffraction (XRD) method. During the process, the XRD of each Cryo-Rolled and annealed sample was analyzed and different phases and phase transitions are measured. The investigated AISI type 304L SS by SPD reveals a microstructure of γ-austenite; α'-marternsite and ɛ-martensite formation depending on the percentage of cryo-rolling. The Vickers hardness (HV) of the samples is also measured. The corrosion rate of the annealed sheet and cryo rolled sample was estimated in boiling nitric acid as per ASTM A-262 practice-C test.

  3. Influence of Heat Input on the Content of Delta Ferrite in the Structure of 304L Stainless Steel GTA Welded Joints

    NASA Astrophysics Data System (ADS)

    Sejč, Pavol; Kubíček, Rastislav

    2011-12-01

    Welding of austenitic stainless steel has its specific issues, even when the weldability is considered good. The main problems of austenitic stainless steel welding are connected with its metallurgical weldability. The amount of the components presented in the structure of stainless steel welded joint affect its properties, therefore the understanding of the behavior of stainless steel during its welding is important for successful processing and allows the fabricators the possibility to manage the resulting issues. This paper is focused on the influence of heat input on the structural changes in GTA welded joints of austenitic stainless steel designated: ASTM SA TP 304L.

  4. Mechanical Behavior and Fractography of 304 Stainless Steel with High Hydrogen Concentration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Au, M.

    2003-02-05

    Hydrogen embrittlement of 304 stainless steel with different hydrogen concentrations has been investigated. An electrochemical technique was used to effectively charge the high level of hydrogen into 304 stainless steel in a short period of time. At 25 ppm of hydrogen, 304 stainless steel loses 10 percent of its original mechanical strength and 20 percent plasticity. Although the ductile feature dominates the fractography, the brittle crown area near the outer surface shows the intergranular rupture effected by hydrogen. At 60 ppm of hydrogen, 304 stainless steel loses 23 percent of its strength and 38 percent plasticity, where the brittle modemore » dominates the fracture of the materials. Experimental results show that hydrogen damage to the performance of 304 stainless steel is significant even at very low levels. The fractograph analysis indicates the high penetration ability of hydrogen in 304 stainless steel. This work also demonstrates the advantages of the electrochemical charging technique in the study of hydrogen embrittlement.« less

  5. Stress Relaxation in Tensile Deformation of 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Li, Xifeng; Li, Jiaojiao; Ding, Wei; Zhao, Shuangjun; Chen, Jun

    2017-02-01

    Improved ductility by stress relaxation has been reported in different kinds of steels. The influence of stress relaxation and its parameters on the ductility of 304 stainless steel has not been established so far. Stress relaxation behavior during tensile tests at different strain rates is studied in 304 stainless steel. It is observed that stress relaxation can obviously increase the elongation of 304 stainless steel in all cases. The elongation improvement of interrupted tension reaches to 14.9% compared with monotonic tension at 0.05 s-1. Contradicting with the published results, stress drop during stress relaxation increases with strain at all strain rates. It is related with dislocation motion velocity variation and martensitic transformation.

  6. Biocompatibly Coated 304 Stainless Steel as Superior Corrosion-Resistant Implant Material to 316L Steel

    NASA Astrophysics Data System (ADS)

    Paul, Subir; Mandal, Chandranath

    2013-10-01

    Surface treatments of 304 stainless steel by electro-coating and passivating in few inorganic electrolytes were found to be very effective in drastically reducing the corrosion rate of the material in stimulated body fluid (SBF) by several orders in comparison to that of 316L steel, presently being used for orthopedic implants. Polarization studies of electrodeposited hydroxyl apatite coating on 304 steel showed remarkably improved corrosion current. Cyclic polarization of the material in SBF reflected the broadened passivity region, much lower passive current, and narrower hysteresis loops. Similar effects were also found through the formation of inorganic coatings by passivation in NaF, CaNO3, and calcium phosphate buffer solutions. Surface characterization by XRD showed the peaks of the respective coating crystals. The morphology of the coatings studied by SEM showed a flake-type structure for hydroxyapatite coating and fine spherical-subspherical particles for other coatings.

  7. The nitrogen effect on Type 304L austenitic stainless steel weld metal welded with a GTA (Gas Tungsten Arc) system under ambient and hyperbaric conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Okagawa, R.K.

    1984-01-01

    Small amounts of nitrogen were injected into Type 304L austenitic stainless steel weld metal. This was accomplished by using an Ar-N/sub 2/ shield gas mixture in combination with a controlled argon atmosphere on autogeneous Gas Tungsten Arc (GTA) welds. Weld metal nitrogen as a function of nitrogen shield gas content and applied pressure was examined. Nitrogen shield gas contents above 4% were found to have a major effect on the weld metal microstructure. The base metal nitrogen did not influence the nitrogen solubility reaction or solidification behavior during welding. For Type 304L austenitic stainless steel, a nitrogen coefficient of 13.4more » was determined for the nickel equivalent expression. 63 refs., 19 figs., 4 tabs.« less

  8. Environmental resistance of oxide tags fabricated on 304L stainless steel via nanosecond pulsed laser irradiation

    DOE PAGES

    Lawrence, Samantha Kay; Adams, David P.; Bahr, David F.; ...

    2015-11-14

    Nanosecond pulsed laser irradiation was used to fabricate colored, mechanically robust oxide “tags” on 304L stainless steel. Immersion in simulated seawater solution, salt fog exposure, and anodic polarization in a 3.5% NaCl solution were employed to evaluate the environmental resistance of these oxide tags. Single layer oxides outside a narrow thickness range (~ 100–150 nm) are susceptible to dissolution in chloride containing environments. The 304L substrates immediately beneath the oxides corrode severely—attributed to Cr-depletion in the melt zone during laser processing. For the first time, multilayered oxides were fabricated with pulsed laser irradiation in an effort to expand the protectivemore » thickness range while also increasing the variety of film colors attainable in this range. Layered films grown using a laser scan rate of 475 mm/s are more resistant to both localized and general corrosion than oxides fabricated at 550 mm/s. Furthermore, in the absence of pre-processing to mitigate Cr-depletion, layered films can enhance environmental stability of the system.« less

  9. Summary of available data for estimating chloride-induced SCC crack growth rates for 304/316 stainless steel.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bryan, Charles R.; Enos, David

    The majority of existing dry storage systems used for spent nuclear fuel (SNF) consist of a welded 304 stainless steel container placed within a passively-ventilated concrete or steel overpack. More recently fielded systems are constructed with dual certified 304/304L and in some cases, 316 or 316L. In service, atmospheric salts, a portion of which will be chloride bearing, will be deposited on the surface of these containers. Initially, the stainless steel canister surface temperatures will be high (exceeding the boiling point of water in many cases) due to decay heat from the SNF. As the SNF cools over time, themore » container surface will also cool, and deposited salts will deliquesce to form potentially corrosive chloride-rich brines. Because austenitic stainless steels are prone to chloride-induced stress corrosion cracking (CISCC), the concern has been raised that SCC may significantly impact long-term canister performance. While the susceptibility of austenitic stainless steels to CISCC in the general sense is well known, the behavior of SCC cracks (i.e., initiation and propagation behavior) under the aforementioned atmospheric conditions is poorly understood.« less

  10. Comparative Mechanical Improvement of Stainless Steel 304 Through Three Methods

    NASA Astrophysics Data System (ADS)

    Mubarok, N.; Notonegoro, H. A.; Thosin, K. A. Z.

    2018-05-01

    Stainless Steel 304 (SS304) is one of stainless steel group widely used in industries for various purposes. In this paper, we compared the experimental process to enhance the mechanical properties of the surface SS304 through three different methods, cold rolled, annealed salt baht bronzing (ASB), and annealed salt baht boronizing-quench (ASB-Q). The phase change in SS304 due to the cold rolled process makes this method is to abandon. The increasing of the annealing time in the ASB method has a nonlinear relationship with the increases in hardness value. Comparing to the increases in hardness value of the ASB method, the hardness value of ASB-Q methods is still lower than that method.

  11. Stress Corrosion Cracking Susceptibility of 304L Substrate and 308L Weld Metal Exposed to a Salt Spray

    PubMed Central

    Hsu, Chia-Hao; Chen, Tai-Cheng; Huang, Rong-Tan; Tsay, Leu-Wen

    2017-01-01

    304 stainless steels (SS) were considered as the materials for a dry storage canister. In this study, ER (Electrode Rod) 308L was utilized as the filler metal for the groove and overlay welds of a 304L stainless steel substrate, which was prepared via a gas tungsten arc-welding process in multiple passes. The electron backscatter diffraction (EBSD) map was used to identify the inherent microstructures in distinct specimens. U-bend and weight-loss tests were conducted by testing the 304L substrates and welds in a salt spray containing 5 wt % NaCl at 80 °C to evaluate their susceptibility to stress corrosion cracking (SCC). Generally, the weight loss of the ER 308L deposit was higher than that of the 304L substrate in a salt spray in the same sample-prepared condition. The dissolution of the skeletal structure in the fusion zone (FZ) was responsible for a greater weight loss of the 308L deposit, especially for the cold-rolled and sensitized specimen. Cold rolling was detrimental and sensitization after cold rolling was very harmful to the SCC resistance of the 304L substrate and 308L deposit. Overall, the SCC susceptibility of each specimen was correlated with its weight loss in each group. PMID:28772547

  12. 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.

  13. Studies on Stress Corrosion Cracking of Super 304H Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Prabha, B.; Sundaramoorthy, P.; Suresh, S.; Manimozhi, S.; Ravishankar, B.

    2009-12-01

    Stress corrosion cracking (SCC) is a common mode of failure encountered in boiler components especially in austenitic stainless steel tubes at high temperature and in chloride-rich water environment. Recently, a new type of austenitic stainless steels called Super304H stainless steel, containing 3% copper is being adopted for super critical boiler applications. The SCC behavior of this Super 304H stainless steel has not been widely reported in the literature. Many researchers have studied the SCC behavior of steels as per various standards. Among them, the ASTM standard G36 has been widely used for evaluation of SCC behavior of stainless steels. In this present work, the SCC behavior of austenitic Fe-Cr-Mn-Cu-N stainless steel, subjected to chloride environments at varying strain conditions as per ASTM standard G36 has been studied. The environments employed boiling solution of 45 wt.% of MgCl2 at 155 °C, for various strain conditions. The study reveals that the crack width increases with increase in strain level in Super 304H stainless steels.

  14. Electrochemical Micromachining with Fiber Laser Masking for 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Li, Xiaohai; Wang, Shuming; Wang, Dong; Tong, Han

    2017-10-01

    In order to fabricate micro structure, the combined machining of electrochemical micro machining (EMM) and laser masking for 304 stainless steel was studied. A device of composite machining of EMM with laser masking was developed, and the experiments of EMM with laser masking were carried out. First, by marking pattern with fiber laser on the surface of 304 stainless steel, the special masking layer can be formed. Through X ray photoelectron spectroscopy (XPS), the corrosion resistance of laser masking layer was analyzed. It is proved by XPS that the iron oxide and chromium oxide on the surface of stainless steel generates due to air oxidation when laser scanning heats. Second, the localization and precision of EMM are improved, since the marking patterns forming on the surface of stainless steel by laser masking play a protective role in the process of subsequent EMM when the appropriate parameters of EMM are selected. At last, the shape and the roughness of the machined samples were measured by SEM and optical profilometer and analyzed. The results show that the rapid fabrication of micro structures on the 304 stainless steel surface can be achieved by EMM with fiber laser masking, which has a good prospect in the field of micro machining.

  15. Effect of Cyclic Thermal Process on Ultrafine Grain Formation in AISI 304L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Ravi Kumar, B.; Mahato, B.; Sharma, Sailaja; Sahu, J. K.

    2009-12-01

    As-received hot-rolled commercial grade AISI 304L austenitic stainless steel plates were solution treated at 1060 °C to achieve chemical homogeneity. Microstructural characterization of the solution-treated material revealed polygonal grains of about 85- μm size along with annealing twins. The solution-treated plates were heavily cold rolled to about 90 pct of reduction in thickness. Cold-rolled specimens were then subjected to thermal cycles at various temperatures between 750 °C and 925 °C. X-ray diffraction showed about 24.2 pct of strain-induced martensite formation due to cold rolling of austenitic stainless steel. Strain-induced martensite formed during cold rolling reverted to austenite by the cyclic thermal process. The microstructural study by transmission electron microscope of the material after the cyclic thermal process showed formation of nanostructure or ultrafine grain austenite. The tensile testing of the ultrafine-grained austenitic stainless steel showed a yield strength 4 to 6 times higher in comparison to its coarse-grained counterpart. However, it demonstrated very poor ductility due to inadequate strain hardenability. The poor strain hardenability was correlated with the formation of strain-induced martensite in this steel grade.

  16. Application Electrochemical Impedance Spectroscopy Methods to Evaluation Corrosion Behavior of Stainless steels 304 in Nanofluids Media

    NASA Astrophysics Data System (ADS)

    Hadi Prajitno, Djoko; Umar, Efrizon; Gustaman Syarif, Dani

    2017-01-01

    Corrosion is a common problem in many engineering metals and alloys. Electrochemical methods are commonly instrument to use as tool to study the corrosion behavior of the metals and alloy. This method was examined interaction between a surface of the metals and alloys in corrosive media. The present paper, the effects of nano particle ZrO2 as an additive to aqua de mineralized on the corrosion behavior of stainless steel were investigated. Electrochemical impedance spectroscopy (EIS) testing was performed in both de mineralized water and demineralized water contain nano particle 0,01% ZrO2 as Nano fluid. Surface morphology examination of the specimens showed that microstructure of stainless steel 304 alloys relatively unchanged after corrosion and EIS testing. According to the corrosion potential examination of the stainless steel 304 in nanofluid media, it showed that stainless steel 304 actively corroded in nanofluida media. The value of anodic Tafel slope stainless steel 304 in nanofluid higher compare with in demineralized water. Tafel polarization examination show that corrosion rate of stainless steel 304 in nanofluid higher compare with corrosin rate in demineralized media.EIS technique show that impedance of stainless steel 304 in nanofluid lower compare with in demineralized media, resulting in an increase in the corrosion rates of these stainless steel 304 specimens in nano fluids

  17. Processing of fine grained AISI 304L austenitic stainless steel by cold rolling and high-temperature short-term annealing

    NASA Astrophysics Data System (ADS)

    Naghizadeh, Meysam; Mirzadeh, Hamed

    2018-05-01

    An advanced thermomechanical process based on the formation and reversion of deformation-induced martensite was used to refine the grain size and enhance the hardness of an AISI 304L austenitic stainless steel. Both low and high reversion annealing temperatures and also the repetition of the whole thermomechanical cycle were considered. While a microstructure with average austenite grain size of a few micrometers was achieved based on cold rolling and high-temperature short-term annealing, an extreme grain refinement up to submicrometer regime was obtained by cold rolling followed by low-temperature long-term annealing. However, the required annealing time was found to be much longer, which negates its appropriateness for industrial production. While a magnificent grain refinement was achieved by one pass of the high-temperature thermomechanical process, the reduction in grain size was negligible by the repetition of the whole cycle. It was found that the hardness of the thermomechanically processed material is much higher than that of the as-received material. The results of the present work were shown to be compatible with the general trend of grain size dependence of hardness for AISI 304L stainless steel based on the Hall-Petch relationship. The results were also discussed based on the X-ray evaluation of dislocation density by modified Williamson-Hall plots.

  18. Impact of Defects in Powder Feedstock Materials on Microstructure of 304L and 316L Stainless Steel Produced by Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Morrow, Benjamin M.; Lienert, Thomas J.; Knapp, Cameron M.; Sutton, Jacob O.; Brand, Michael J.; Pacheco, Robin M.; Livescu, Veronica; Carpenter, John S.; Gray, George T.

    2018-05-01

    Recent work in both 304L and 316L stainless steel produced by additive manufacturing (AM) has shown that in addition to the unique, characteristic microstructures formed during the process, a fine dispersion of sub-micron particles, with a chemistry different from either the powder feedstock or the expected final material, are evident in the final microstructure. Such fine-scale features can only be resolved using transmission electron microscopy (TEM) or similar techniques. The present work uses electron microscopy to study both the initial powder feedstock and microstructures in final AM parts. Special attention is paid to the chemistry and origin of these nanoscale particles in several different metal alloys, and their impact on the final build. Comparisons to traditional, wrought material will be made.

  19. Experiments and modeling to characterize microstructure and hardness in 304L

    DOE PAGES

    Deibler, Lisa Anne; Brown, Arthur; Puskar, Joseph D.

    2017-01-12

    Drawn 304L stainless steel tubing was subjected to 42 different annealing heat treatments with the goal of initializing a microstructural model to select a heat treatment to soften the tubing from a hardness of 305 Knoop to 225–275 Knoop. The amount of recrystallization and grain size caused by 18 heat treatments were analyzed via optical microscopy and image analysis, revealing the full range of recrystallization from 0 to 100%. The formation of carbides during the longer duration and higher-temperature heat treatments was monitored via transmission electron microscope evaluation. The experimental results informed a model which includes recovery, recrystallization, and grainmore » growth to predict microstructure and hardness. After initialization of the model, it was able to predict hardness with a R 2 value of 0.95 and recrystallization with an R 2 value of 0.99. As a result, the model was then utilized in the design and testing of a heat treatment to soften the tubing.« less

  20. Flow stress equations for type 304 stainless and AISI 1055 steels

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dadras, P.

    A model for stress-strain behavior under hot working conditions has been proposed. Based on experimental data, equations for the dependence of flow stress on strain, strain rate, and temperature have been developed. Application to type 304 stainless steel and AISI 1055 steel has been demonstrated.

  1. Delta ferrite is ubiquitous in type 304 stainless steel: Consequences for magnetic characterization

    NASA Astrophysics Data System (ADS)

    Graham, C. D.; Lorenz, B. E.

    2018-07-01

    Using a vibrating-sample magnetometer with a maximum field of 20.5 kOe, we have measured over 50 samples of annealed 304 stainless steel, which is usually considered to be non-magnetic. In almost every case, we observe the presence of a small, usually less than 0.01, fraction of a ferromagnetic phase, which we believe to be equilibrium bcc delta ferrite. The consequences of this observation for the measurement and specification of the magnetic properties of annealed 304 stainless are discussed. Our measurements also establish the most likely value for the magnetic permeability of the fcc austenitic phase in 304 stainless steel austenite as 1.0033 ± 0.0003.

  2. Oxidation of 304 stainless steel in high-temperature steam

    NASA Astrophysics Data System (ADS)

    Ishida, Toshihisa; Harayama, Yasuo; Yaguchi, Sinnosuke

    1986-08-01

    An experiment on oxidation of 304 stainless steel was performed in steam between 900°C and 1350°C, using the spare cladding of the reactor of the nuclear-powered ship Mutsu. The temperature range was appropriate for a postulated loss of coolant accident (LOCA) analysis of a LWR. The oxidation kinetics were found to obey the parabolic law during the first period of 8 min. After the first period, the parabolic reaction rate constant decreased in the case of heating temperatures between 1100°C and 1250°C. At 1250°C, especially, a marked decrease was observed in the oxide scale-forming kinetics when the surface treated initially by mechanical polishing and given a residual stress. This enhanced oxidation resistance was attributed to the presence of a chromium-enriched layer which was detected by use of an X-ray microanalyzer. The oxidation kinetics equation obtained for the first 8 min is applicable to the model calculation of a hypothetical LOCA in a LWR, employing 304 stainless steel cladding.

  3. Comparative Study of Hardening Mechanisms During Aging of a 304 Stainless Steel Containing α'-Martensite

    NASA Astrophysics Data System (ADS)

    Jeong, S. W.; Kang, U. G.; Choi, J. Y.; Nam, W. J.

    2012-09-01

    Strain aging and hardening behaviors of a 304 stainless steel containing deformation-induced martensite were investigated by examining mechanical properties and microstructural evolution for different aging temperature and time. Introduced age hardening mechanisms of a cold rolled 304 stainless steel were the additional formation of α'-martensite, hardening of α'-martensite, and hardening of deformed austenite. The increased amount of α'-martensite at an aging temperature of 450 °C confirmed the additional formation of α'-martensite as a hardening mechanism in a cold rolled 304 stainless steel. Additionally, the increased hardness in both α'-martensite and austenite phases with aging temperature proved that hardening of both α'-martensite and austenite phases would be effective as hardening mechanisms in cold rolled and aged 304 stainless steels. The results suggested that among hardening mechanisms, hardening of an α'-martensite phase, including the diffusion of interstitial solute carbon atoms to dislocations and the precipitation of fine carbide particles would become a major hardening mechanism during aging of cold rolled 304 stainless steels.

  4. Friction behavior of 304 stainless steel of varying hardness lubricated with benzene and some benzyl structures

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1974-01-01

    The lubricating properties of some benzyl and benzene structures were determined by using 304 stainless steel surfaces strained to various hardness. Friction coefficients and wear track widths were measured with a Bowden-Leben type friction apparatus by using a pin-on-disk specimen configuration. Results obtained indicate that benzyl monosulfide, dibenzyl disulfide, and benzyl alcohol resulted in the lowest friction coefficients for 304 stainless steel, while benzyl ether provided the least surface protection and gave the highest friction. Strainhardening of the 304 stainless steel prior to sliding resulted in reduced friction in dry sliding. With benzyl monosulfide, dibenzyl disulfide, and benzyl alcohol changes in 304 stainless steel hardness had no effect upon friction behavior.

  5. Surface buffing and its effect on chloride induced SCC of 304L austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    kumar, Pandu Sunil; Ghosh Acharyya, Swati; Ramana Rao, S. V.; Kapoor, Komal

    2018-02-01

    The study focuses on the impact of buffing operation on the stress corrosion cracking (SCC) susceptibility of 304L austenitic stainless steel (SS). The SCC susceptibility of the buffed surfaces were determined by testing in boiling magnesium chloride (MgCl2) environment as per ASTM G 36. Test was conducted for 3hr, 9hr and 72hr to study the SCC susceptibility. Buffed surfaces were resistant to SCC even after 72hr of exposure to boiling MgCl2. The surface and cross section of the samples were examined for both before and after exposure to boiling MgCl2 and was characterized using optical microscopy. The study revealed that buffing operation induces compressive residual stresses on the surface, which helps in protecting the surface from SCC.

  6. In Situ Neutron Diffraction Study of the Influence of Microstructure on the Mechanical Response of Additively Manufactured 304L Stainless Steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brown, D. W.; Adams, D. P.; Balogh, L.

    In situ neutron diffraction measurements were completed for this study during tensile and compressive deformation of stainless steel 304L additively manufactured (AM) using a high power directed energy deposition process. Traditionally produced wrought 304L material was also studied for comparison. The AM material exhibited roughly 200 MPa higher flow stress relative to the wrought material. Crystallite size, crystallographic texture, dislocation density, and lattice strains were all characterized to understand the differences in the macroscopic mechanical behavior. The AM material’s initial dislocation density was about 10 times that of the wrought material, and the flow strength of both materials obeyed themore » Taylor equation, indicating that the AM material’s increased yield strength was primarily due to greater dislocation density. Finally, a ~50 MPa flow strength tension/compression asymmetry was observed in the AM material, and several potential causes were examined.« less

  7. In Situ Neutron Diffraction Study of the Influence of Microstructure on the Mechanical Response of Additively Manufactured 304L Stainless Steel

    DOE PAGES

    Brown, D. W.; Adams, D. P.; Balogh, L.; ...

    2017-10-10

    In situ neutron diffraction measurements were completed for this study during tensile and compressive deformation of stainless steel 304L additively manufactured (AM) using a high power directed energy deposition process. Traditionally produced wrought 304L material was also studied for comparison. The AM material exhibited roughly 200 MPa higher flow stress relative to the wrought material. Crystallite size, crystallographic texture, dislocation density, and lattice strains were all characterized to understand the differences in the macroscopic mechanical behavior. The AM material’s initial dislocation density was about 10 times that of the wrought material, and the flow strength of both materials obeyed themore » Taylor equation, indicating that the AM material’s increased yield strength was primarily due to greater dislocation density. Finally, a ~50 MPa flow strength tension/compression asymmetry was observed in the AM material, and several potential causes were examined.« less

  8. Gas tungsten arc welding and friction stir welding of ultrafine grained AISI 304L stainless steel: Microstructural and mechanical behavior characterization

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sabooni, S., E-mail: s.sabooni@ma.iut.ac.ir; Karimzadeh, F.; Enayati, M.H.

    In the present study, an ultrafine grained (UFG) AISI 304L stainless steel with the average grain size of 650 nm was successfully welded by both gas tungsten arc welding (GTAW) and friction stir welding (FSW). GTAW was applied without any filler metal. FSW was also performed at a constant rotational speed of 630 rpm and different welding speeds from 20 to 80 mm/min. Microstructural characterization was carried out by High Resolution Scanning Electron Microscopy (HRSEM) with Electron Backscattered Diffraction (EBSD) and Transmission Electron Microscopy (TEM). Nanoindentation, microhardness measurements and tensile tests were also performed to study the mechanical properties ofmore » the base metal and weldments. The results showed that the solidification mode in the GTAW welded sample is FA (ferrite–austenite) type with the microstructure consisting of an austenite matrix embedded with lath type and skeletal type ferrite. The nugget zone microstructure in the FSW welded samples consisted of equiaxed dynamically recrystallized austenite grains with some amount of elongated delta ferrite. Sigma phase precipitates were formed in the region ahead the rotating tool during the heating cycle of FSW, which were finally fragmented into nanometric particles and distributed in the weld nugget. Also there is a high possibility that the existing delta ferrite in the microstructure rapidly transforms into sigma phase particles during the short thermal cycle of FSW. These suggest that high strain and deformation during FSW can promote sigma phase formation. The final austenite grain size in the nugget zone was found to decrease with increasing Zener–Hollomon parameter, which was obtained quantitatively by measuring the peak temperature, calculating the strain rate during FSW and exact examination of hot deformation activation energy by considering the actual grain size before the occurrence of dynamic recrystallization. Mechanical properties observations showed that the

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 ofmore » 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.« less

  10. A three-dimensional thermal finite element analysis of AISI 304 stainless steel and copper dissimilar weldment

    NASA Astrophysics Data System (ADS)

    Singh, Gurdeep; Saxena, Ravindra K.; Pandey, Sunil

    2018-04-01

    The aim of this study to developed a 3-D thermal finite element model for dissimilar material welding of AISI-304 stainless steel and copper. Welding of similar material is widely studied using experimental and numerical methods but the problem becomes trivial for the welding of dissimilar materials especially in ferrous and nonferrous materials. Finite element analysis of dissimilar material welding is a cost-effective method for the understanding and analysis of the process. The finite element analysis has been performed to predict the heat affected zone and temperature distribution in AISI-304 stainless steel and copper dissimilar weldment using MSC Marc 2017®. Due to the difference in physical properties of these materials the behavior of heat affected zone and temperature distribution are perceived to be different. To verify the accuracy of the thermal finite element model, the welding process was simulated with butt-welded joints having same dimensions and parameters from Attarha and Far [1]. It is found from the study that the heat affected zone is larger in copper weld pads than in AISI 304 stainless steel due to large difference in thermal conductivity of these two weld pads.

  11. Formability analysis of austenitic stainless steel-304 under warm conditions

    NASA Astrophysics Data System (ADS)

    Lade, Jayahari; Singh, Swadesh Kumar; Banoth, Balu Naik; Gupta, Amit Kumar

    2013-12-01

    A warm deep drawing process of austenitic stainless steel-304 (ASS-304) of circular blanks with coupled ther mal analysis is studied in this article. 65 mm blanks were deep drawn at different temperatures and thickness distribution is experimentally measured after cutting the drawn component into two halves. The process is simulated using explicit fin ite element code LS-DYNA. A Barlat 3 parameter model is used in the simulation, as the material is anisotropic up to 30 0°C. Material properties for the simulation are determined at different temperatures using a 5 T UTM coupled with a furn ace. In this analysis constant punch speed and variable blank holder force (BHF) is applied to draw cups without wrinkle.

  12. Effect of martensitic transformation on springback behavior of 304L austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Fathi, H.; Mohammadian Semnani, H. R.; Emadoddin, E.; Sadeghi, B. Mohammad

    2017-09-01

    The present paper studies the effect of martensitic transformation on the springback behavior of 304L austenitic stainless steel. Martensite volume fraction was determined at the bent portion under various strain rates after bending test. Martensitic transformation has a significant effect on the springback behavior of this material. The findings of this study indicated that the amount of springback was reduced under a situation of low strain rate, while a higher amount of springback was obtained with a higher strain rate. The reason for this phenomenon is that higher work hardening occurs during the forming process with the low strain rate due to the higher martensite volume fraction, therefore the formability of the sheet is enhanced and it leads to a decreased amount of springback after the bending test. Dependency of the springback on the martensite volume fraction and strain rate was expressed as formulas from the results of the experimental tests and simulation method. Bending tests were simulated using LS-DYNA software and utilizing MAT_TRIP to determine the martensite volume fraction and strain under various strain rates. Experimental result reveals good agreement with the simulation method.

  13. Experimental and numerical study on optimization of the single point incremental forming of AINSI 304L stainless steel sheet

    NASA Astrophysics Data System (ADS)

    Saidi, B.; Giraud-Moreau, L.; Cherouat, A.; Nasri, R.

    2017-09-01

    AINSI 304L stainless steel sheets are commonly formed into a variety of shapes for applications in the industrial, architectural, transportation and automobile fields, it’s also used for manufacturing of denture base. In the field of dentistry, there is a need for personalized devises that are custom made for the patient. The single point incremental forming process is highly promising in this area for manufacturing of denture base. The single point incremental forming process (ISF) is an emerging process based on the use of a spherical tool, which is moved along CNC controlled tool path. One of the major advantages of this process is the ability to program several punch trajectories on the same machine in order to obtain different shapes. Several applications of this process exist in the medical field for the manufacturing of personalized titanium prosthesis (cranial plate, knee prosthesis...) due to the need of product customization to each patient. The objective of this paper is to study the incremental forming of AISI 304L stainless steel sheets for future applications in the dentistry field. During the incremental forming process, considerable forces can occur. The control of the forming force is particularly important to ensure the safe use of the CNC milling machine and preserve the tooling and machinery. In this paper, the effect of four different process parameters on the maximum force is studied. The proposed approach consists in using an experimental design based on experimental results. An analysis of variance was conducted with ANOVA to find the input parameters allowing to minimize the maximum forming force. A numerical simulation of the incremental forming process is performed with the optimal input process parameters. Numerical results are compared with the experimental ones.

  14. Anaerobic Corrosion of 304 Stainless Steel Caused by the Pseudomonas aeruginosa Biofilm

    PubMed Central

    Jia, Ru; Yang, Dongqing; Xu, Dake; Gu, Tingyue

    2017-01-01

    Pseudomonas aeruginosa is a ubiquitous bacterium capable of forming problematic biofilms in many environments. They cause biocorrosion of medical implants and industrial equipment and infrastructure. Aerobic corrosion of P. aeruginosa against stainless steels has been reported by some researchers while there is a lack of reports on anaerobic P. aeruginosa corrosion in the literature. In this work, the corrosion by a wild-type P. aeruginosa (strain PAO1) biofilm against 304 stainless steel (304 SS) was investigated under strictly anaerobic condition for up to 14 days. The anaerobic corrosion of 304 SS by P. aeruginosa was reported for the first time. Results showed that the average sessile cell counts on 304 SS coupons after 7- and 14-day incubations were 4.8 × 107 and 6.2 × 107 cells/cm2, respectively. Scanning electron microscopy and confocal laser scanning microscopy corroborated the sessile cell counts. The X-ray diffraction analysis identified the corrosion product as iron nitride, confirming that the corrosion was caused by the nitrate reducing biofilm. The largest pit depths on 304 SS surfaces after the 7- and 14-day incubations with P. aeruginosa were 3.9 and 7.4 μm, respectively. Electrochemical tests corroborated the pitting data. PMID:29230206

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 reducingmore » the solution that will be contained in either the secondary waste receiver tank or concentrate tank.« less

  16. Some aspects of thermomechanical fatigue of AISI 304L stainless steel: Part I. creep- fatigue damage

    NASA Astrophysics Data System (ADS)

    Zauter, R.; Christ, H. J.; Mughrabi, H.

    1994-02-01

    Thermomechanical fatigue (TMF) tests on the austenitic stainless steel AISI 304L have been conducted under “true≓ plastic-strain control in vacuum. This report considers the damage oc-curring during TMF loading. It is shown how the temperature interval and the phasing (in-phase, out-of-phase) determine the mechanical response and the lifetime of the specimens. If creep-fatigue interaction takes place during in-phase cycling, the damage occurs inside the ma-terial, leading to intergranular cracks which reduce the lifetime considerably. Out-of-phase cy-cling inhibits creep-induced damage, and no lifetime reduction occurs, even if the material is exposed periodically to temperatures in the creep regime. A formula is proposed which allows prediction of the failure mode, depending on whether creep-fatigue damage occurs or not. At a given strain rate, the formula is able to estimate the temperature of transition between pure fatigue and creep-fatigue damage.

  17. Comparative study on corrosion resistance and in vitro biocompatibility of bulk nanocrystalline and microcrystalline biomedical 304 stainless steel.

    PubMed

    Nie, F L; Wang, S G; Wang, Y B; Wei, S C; Zheng, Y F

    2011-07-01

    SUS 304 stainless steels have been widely used in orthodontics and implants such as archwires, brackets, and screws. The purpose of present study was to investigate the biocompatibility of both the commercial microcrystalline biomedical 304 stainless steel (microcrystalline 304ss) and novel-fabricated nanocrystalline 304 stainless steel (nanocrystalline 304ss). Bulk nanocrystalline 304ss sheets had been successfully prepared by microcrystalline 304ss plates using severe rolling technique. The electrochemical corrosion and ion release behavior immersion in artificial saliva were measured to evaluate the property of biocorrosion in oral environment. The cell lines of murine and human cell lines from oral and endothelial environment were co-cultured with extracts to evaluate the cytotoxicity and provide referential evidence in vivo. The polarization resistance trials indicated that nanocrystalline 304ss is more corrosion resistant than the microcrystalline 304ss in oral-like environment with higher corrosion potential, and the amount of toxic ions released into solution after immersion is lower than that of the microcrystalline 304ss and the daily dietary intake level. The cytotoxicity results also elucidated that nanocrystalline 304ss is biologically compatible in vitro, even better than that of microcrystalline 304ss. Based on the much higher mechanical and physical performances, nanocrystalline 304ss with enhanced biocorrosion property, well-behaved in vitro cytocompatibility can be a promising alternative in orthodontics and fixation fields in oral cavity. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  18. Weld pool development during GTA and laser beam welding of Type 304 stainless steel; Part I - theoretical analysis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zacharia, T.; David, S.A.; Vitek, J.M.

    1989-12-01

    A computational and experimental study was carried out to quantitatively understand the influence of the heat flow and the fluid flow in the transient development of the weld pool during gas tungsten arc (GTA) and laser beam welding of Type 304 stainless steel. Stationary gas tungsten arc and laser beam welds were made on two heats of Type 304 austenitic stainless steels containing 90 ppm sulfur and 240 ppm sulfur. A transient heat transfer model was utilized to simulate the heat flow and fluid flow in the weld pool. In this paper, the results of the heat flow and fluidmore » flow analysis are presented.« less

  19. Failure Assessment Diagram for Brazed 304 Stainless Steel Joints

    NASA Technical Reports Server (NTRS)

    Flom, Yory

    2011-01-01

    Interaction equations were proposed earlier to predict failure in Albemet 162 brazed joints. Present study demonstrates that the same interaction equations can be used for lower bound estimate of the failure criterion in 304 stainless steel joints brazed with silver-based filler metals as well as for construction of the Failure Assessment Diagrams (FAD).

  20. Influence of Size on the Microstructure and Mechanical Properties of an AISI 304L Stainless Steel—A Comparison between Bulk and Fibers

    PubMed Central

    Baldenebro-Lopez, Francisco J.; Gomez-Esparza, Cynthia D.; Corral-Higuera, Ramon; Arredondo-Rea, Susana P.; Pellegrini-Cervantes, Manuel J.; Ledezma-Sillas, Jose E.; Martinez-Sanchez, Roberto; Herrera-Ramirez, Jose M.

    2015-01-01

    In this work, the mechanical properties and microstructural features of an AISI 304L stainless steel in two presentations, bulk and fibers, were systematically studied in order to establish the relationship among microstructure, mechanical properties, manufacturing process and effect on sample size. The microstructure was analyzed by XRD, SEM and TEM techniques. The strength, Young’s modulus and elongation of the samples were determined by tensile tests, while the hardness was measured by Vickers microhardness and nanoindentation tests. The materials have been observed to possess different mechanical and microstructural properties, which are compared and discussed. PMID:28787949

  1. Surface temperature distribution of GTA weld pools on thin-plate 304 stainless steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zacharia, T.; David, S.A.; Vitek, J.M.

    1995-11-01

    A transient multidimensional computational model was utilized to study gas tungsten arc (GTA) welding of thin-plate 304 stainless steel (SS). The model eliminates several of the earlier restrictive assumptions including temperature-independent thermal-physical properties. Consequently, all important thermal-physical properties were considered as temperature dependent throughout the range of temperatures experienced by the weld metal. The computational model was used to predict surface temperature distribution of the GTA weld pools in 1.5-mm-thick AISI 304 SS. The welding parameters were chosen so as to correspond with an earlier experimental study that produced high-resolution surface temperature maps. One of the motivations of the presentmore » study was to verify the predictive capability of the computational model. Comparison of the numerical predictions and experimental observations indicate excellent agreement, thereby verifying the model.« less

  2. Correlation of radiation-induced changes in microstructure/microchemistry, density and thermo-electric power of type 304L and 316 stainless steels irradiated in the Phénix reactor

    NASA Astrophysics Data System (ADS)

    Renault Laborne, Alexandra; Gavoille, Pierre; Malaplate, Joël; Pokor, Cédric; Tanguy, Benoît

    2015-05-01

    Annealed specimens of type 304L and 316 stainless steel and cold-worked 316 specimens were irradiated in the Phénix reactor in the temperature range 381-394 °C and to different damage doses up to 39 dpa. The microstructure and microchemistry of both 304L and 316 have been examined using the combination of the different techniques of TEM to establish the void swelling and precipitation behavior under neutron irradiation. TEM observations are compared with results of measurements of immersion density and thermo-electric power obtained on the same irradiated stainless steels. The similarities and differences in their behavior on different scales are used to understand the factors in terms of the chemical composition and metallurgical state of steels, affecting the precipitation under irradiation and the swelling behavior. Irradiation induces the formation of some precipitate phases (e.g., M6C and M23C6-type carbides, and γ'- and G-phases), Frank loops and cavities. According to the metallurgical state and chemical composition of the steel, the amount of each type of radiation-induced defects is not the same, affecting their density and thermo-electric power.

  3. L2 Milestone 5433: Characterization of Dynamic Behavior of AM and Conventionally Processed Stainless Steel (316L and 304L)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gray, George Thompson; Livescu, Veronica; Rigg, P. A.

    For additive manufacturing (AM) of metallic materials, the certification and qualification paradigm needs to evolve as there currently exists no broadly accepted “ASTM- or DIN-type” additive manufacturing certified process or AM-material produced specifications. Accordingly, design, manufacture, and thereafter implementation and insertion of AM materials to meet engineering applications requires detailed quantification of the constitutive (strength and damage) properties of these evolving materials, across the spectrum of metallic AM methods, in comparison/contrast to conventionally-manufactured metals and alloys. This report summarizes the 316L SS research results and presents initial results of the follow-on study of 304L SS. For the AM-316L SS investigation,more » cylindrical samples of 316L SS were produced using a LENS MR-7 laser additive manufacturing system from Optomec (Albuquerque, NM) equipped with a 1kW Yb-fiber laser. The microstructure of the AM-316L SS was characterized in both the “as-built” Additively Manufactured state and following a heat-treatment designed to obtain full recrystallization to facilitate comparison with annealed wrought 316L SS. The dynamic shock-loading-induced damage evolution and failure response of all three 316L SS materials was quantified using flyer-plate impact driven spallation experiments at peak stresses of 4.5 and 6.35 GPa. The results of these studies are reported in detail in the first section of the report. Publication of the 316L SS results in an archival journal is planned. Following on from the 316L SS completed work, initial results on a study of AM 304L SS are in progress and presented herein. Preliminary results on the structure/dynamic spallation property behavior of AM-304L SS fabricated using both the directed-energy LENS and an EOS powder-bed AM techniques in comparison to wrought 304L SS is detailed in this Level 2 Milestone report.« less

  4. Simulation and experimental comparison of the thermo-mechanical history and 3D microstructure evolution of 304L stainless steel tubes manufactured using LENS

    NASA Astrophysics Data System (ADS)

    Johnson, Kyle L.; Rodgers, Theron M.; Underwood, Olivia D.; Madison, Jonathan D.; Ford, Kurtis R.; Whetten, Shaun R.; Dagel, Daryl J.; Bishop, Joseph E.

    2018-05-01

    Additive manufacturing enables the production of previously unachievable designs in conjunction with time and cost savings. However, spatially and temporally fluctuating thermal histories can lead to residual stress states and microstructural variations that challenge conventional assumptions used to predict part performance. Numerical simulations offer a viable way to explore the root causes of these characteristics, and can provide insight into methods of controlling them. Here, the thermal history of a 304L stainless steel cylinder produced using the Laser Engineered Net Shape process is simulated using finite element analysis (FEA). The resultant thermal history is coupled to both a solid mechanics FEA simulation to predict residual stress and a kinetic Monte Carlo model to predict the three-dimensional grain structure evolution. Experimental EBSD measurements of grain structure and in-process infrared thermal data are compared to the predictions.

  5. Simulation and experimental comparison of the thermo-mechanical history and 3D microstructure evolution of 304L stainless steel tubes manufactured using LENS

    NASA Astrophysics Data System (ADS)

    Johnson, Kyle L.; Rodgers, Theron M.; Underwood, Olivia D.; Madison, Jonathan D.; Ford, Kurtis R.; Whetten, Shaun R.; Dagel, Daryl J.; Bishop, Joseph E.

    2017-12-01

    Additive manufacturing enables the production of previously unachievable designs in conjunction with time and cost savings. However, spatially and temporally fluctuating thermal histories can lead to residual stress states and microstructural variations that challenge conventional assumptions used to predict part performance. Numerical simulations offer a viable way to explore the root causes of these characteristics, and can provide insight into methods of controlling them. Here, the thermal history of a 304L stainless steel cylinder produced using the Laser Engineered Net Shape process is simulated using finite element analysis (FEA). The resultant thermal history is coupled to both a solid mechanics FEA simulation to predict residual stress and a kinetic Monte Carlo model to predict the three-dimensional grain structure evolution. Experimental EBSD measurements of grain structure and in-process infrared thermal data are compared to the predictions.

  6. Structural Characterization of Sputter-Deposited 304 Stainless Steel+10 wt pct Al Coatings

    NASA Astrophysics Data System (ADS)

    Seelam, Uma Maheswara Rao; Suryanarayana, C.; Heinrich, Helge; Ohkubo, Tadakatsu; Hono, Kazuhiro; Cheruvu, N. S.

    2012-08-01

    An SS304 + 10 wt pct Al (with a nominal composition of Fe-18Cr-8Ni-10Al by wt pct and corresponding to Fe-17Cr-6Ni-17Al by at. pct) coating was deposited on a 304-type austenitic stainless steel (Fe-18Cr-8Ni by wt pct) substrate by the magnetron sputter-deposition technique using two targets: 304-type stainless steel (SS304) and Al. The as-deposited coatings were characterized by X-ray diffraction, transmission electron microscopy, and three-dimensional (3-D) atom probe techniques. The coating consists of columnar grains with α ferrite with the body-centered cubic (bcc) (A2) structure and precipitates with a B2 structure. It also has a deposition-induced layered structure with two alternative layers (of 3.2 nm wavelength): one rich in Fe and Cr, and the other enriched with Al and Ni. The layer with high Ni and Al contents has a B2 structure. Direct confirmation of the presence of B2 phase in the coating was obtained by electron diffraction and 3-D atom probe techniques.

  7. Superior radiation-resistant nanoengineered austenitic 304L stainless steel for applications in extreme radiation environments

    NASA Astrophysics Data System (ADS)

    Sun, C.; Zheng, S.; Wei, C. C.; Wu, Y.; Shao, L.; Yang, Y.; Hartwig, K. T.; Maloy, S. A.; Zinkle, S. J.; Allen, T. R.; Wang, H.; Zhang, X.

    2015-01-01

    Nuclear energy provides more than 10% of electrical power internationally, and the increasing engagement of nuclear energy is essential to meet the rapid worldwide increase in energy demand. A paramount challenge in the development of advanced nuclear reactors is the discovery of advanced structural materials that can endure extreme environments, such as severe neutron irradiation damage at high temperatures. It has been known for decades that high dose radiation can introduce significant void swelling accompanied by precipitation in austenitic stainless steel (SS). Here we report, however, that through nanoengineering, ultra-fine grained (UFG) 304L SS with an average grain size of ~100 nm, can withstand Fe ion irradiation at 500°C to 80 displacements-per-atom (dpa) with moderate grain coarsening. Compared to coarse grained (CG) counterparts, swelling resistance of UFG SS is improved by nearly an order of magnitude and swelling rate is reduced by a factor of 5. M23C6 precipitates, abundant in irradiated CG SS, are largely absent in UFG SS. This study provides a nanoengineering approach to design and discover radiation tolerant metallic materials for applications in extreme radiation environments.

  8. Superior radiation-resistant nanoengineered austenitic 304L stainless steel for applications in extreme radiation environments

    DOE PAGES

    Sun, C.; Zheng, S.; Wei, C. C.; ...

    2015-01-15

    Nuclear energy provides more than 10% of electrical power internationally, and the increasing engagement of nuclear energy is essential to meet the rapid worldwide increase in energy demand. A paramount challenge in the development of advanced nuclear reactors is the discovery of advanced structural materials that can endure extreme environments, such as severe neutron irradiation damage at high temperatures. It has been known for decades that high dose radiation can introduce significant void swelling accompanied by precipitation in austenitic stainless steel (SS). Here we report, however, that through nanoengineering, ultra-fine grained (UFG) 304L SS with an average grain size ofmore » ~100 nm, can withstand Fe ion irradiation at 500°C to 80 displacements-per-atom (dpa) with moderate grain coarsening. Compared to coarse grained (CG) counterparts, swelling resistance of UFG SS is improved by nearly an order of magnitude and swelling rate is reduced by a factor of 5. M₂₃C₆ precipitates, abundant in irradiated CG SS, are largely absent in UFG SS. This study provides a nanoengineering approach to design and discover radiation tolerant metallic materials for applications in extreme radiation environments.« less

  9. Superior radiation-resistant nanoengineered austenitic 304L stainless steel for applications in extreme radiation environments.

    PubMed

    Sun, C; Zheng, S; Wei, C C; Wu, Y; Shao, L; Yang, Y; Hartwig, K T; Maloy, S A; Zinkle, S J; Allen, T R; Wang, H; Zhang, X

    2015-01-15

    Nuclear energy provides more than 10% of electrical power internationally, and the increasing engagement of nuclear energy is essential to meet the rapid worldwide increase in energy demand. A paramount challenge in the development of advanced nuclear reactors is the discovery of advanced structural materials that can endure extreme environments, such as severe neutron irradiation damage at high temperatures. It has been known for decades that high dose radiation can introduce significant void swelling accompanied by precipitation in austenitic stainless steel (SS). Here we report, however, that through nanoengineering, ultra-fine grained (UFG) 304 L SS with an average grain size of ~100 nm, can withstand Fe ion irradiation at 500 °C to 80 displacements-per-atom (dpa) with moderate grain coarsening. Compared to coarse grained (CG) counterparts, swelling resistance of UFG SS is improved by nearly an order of magnitude and swelling rate is reduced by a factor of 5. M(23)C(6) precipitates, abundant in irradiated CG SS, are largely absent in UFG SS. This study provides a nanoengineering approach to design and discover radiation tolerant metallic materials for applications in extreme radiation environments.

  10. Superior radiation-resistant nanoengineered austenitic 304L stainless steel for applications in extreme radiation environments

    PubMed Central

    Sun, C.; Zheng, S.; Wei, C. C.; Wu, Y.; Shao, L.; Yang, Y.; Hartwig, K. T.; Maloy, S. A.; Zinkle, S. J.; Allen, T. R.; Wang, H.; Zhang, X.

    2015-01-01

    Nuclear energy provides more than 10% of electrical power internationally, and the increasing engagement of nuclear energy is essential to meet the rapid worldwide increase in energy demand. A paramount challenge in the development of advanced nuclear reactors is the discovery of advanced structural materials that can endure extreme environments, such as severe neutron irradiation damage at high temperatures. It has been known for decades that high dose radiation can introduce significant void swelling accompanied by precipitation in austenitic stainless steel (SS). Here we report, however, that through nanoengineering, ultra-fine grained (UFG) 304L SS with an average grain size of ~100 nm, can withstand Fe ion irradiation at 500°C to 80 displacements-per-atom (dpa) with moderate grain coarsening. Compared to coarse grained (CG) counterparts, swelling resistance of UFG SS is improved by nearly an order of magnitude and swelling rate is reduced by a factor of 5. M23C6 precipitates, abundant in irradiated CG SS, are largely absent in UFG SS. This study provides a nanoengineering approach to design and discover radiation tolerant metallic materials for applications in extreme radiation environments. PMID:25588326

  11. Effect of cold deformation on the electrochemical behaviour of 304L stainless steel in contaminated sulfuric acid environment

    NASA Astrophysics Data System (ADS)

    Luo, Hong; Su, Huaizhi; Ying, Guobing; Dong, Chaofang; Li, Xiaogang

    2017-12-01

    The effect of cold deformation on the microstructure and electrochemical corrosion behaviour of 304L stainless steel in contaminated sulfuric acid solutions (simulated proton exchange membrane fuel cells environments) were evaluated using electron backscatter diffraction analyses, electrochemical measurements, and surface analyses. The internal microstructure,including the grain sizes, angles of the grain boundaries, low coincidence site lattice boundaries, and phase transformations, was changed due to the cold deformation. No noticeable modifications of the pitting corrosion potential were observed during the various deformations, except for a slight enhancement in the passive current density with an increase in the deformation. The CrO3 and metal Ni species in the passive film were investigated after deformation. After heavy deformation (greater than 60%), nickel oxides were detected. Moreover, the Cr/Fe and O2-/OH- ratios in the passive film were higher before deformation, and they decreased with an increase in the deformation level.

  12. Oxidation and corrosion behavior of modified-composition, low-chromium 304 stainless steel alloys

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Barrett, C. A.

    1977-01-01

    The effects of substituting less strategic elements than Cr on the oxidation and corrosion resistance of AISI 304 stainless steel were investigated. Cyclic oxidation resistance was evaluated at 870 C. Corrosion resistance was determined by exposure of specimens to a boiling copper-rich solution of copper sulfate and sulfuric acid. Alloy substitutes for Cr included Al, Mn, Mo, Si, Ti, V, Y, and misch metal. A level of about 12% Cr was the minimum amount of Cr required for adequate oxidation and corrosion resistance in the modified composition 304 stainless steels. This represents a Cr saving of at least 33%. Two alloys containing 12% Cr and 2% Al plus 2% Mo and 12% Cr plus 2.65% Si were identified as most promising for more detailed evaluation.

  13. Multitechnique characterisation of 304L surface states oxidised at high temperature in steam and air atmospheres

    NASA Astrophysics Data System (ADS)

    Mamede, Anne-Sophie; Nuns, Nicolas; Cristol, Anne-Lise; Cantrel, Laurent; Souvi, Sidi; Cristol, Sylvain; Paul, Jean-François

    2016-04-01

    In case of a severe accident occurring in a nuclear reactor, surfaces of the reactor coolant system (RCS), made of stainless steel (304L) rich in Cr (>10%) and Ni (8-12%), are oxidised. Fission products (FPs) are released from melt fuel and flow through the RCS. A part of them is deposited onto surfaces either by vapour condensation or by aerosol deposition mechanisms. To be able to understand the nature of interactions between these FPs and the RCS surfaces, a preliminary step is to characterize the RSC surface states in steam and air atmosphere at high temperatures. Pieces of 304L stainless steel have been treated in a flow reactor at two different temperatures (750 °C and 950 °C) for two different exposition times (24 h and 72 h). After surfaces analysing by a unique combination of surface analysis techniques (XPS, ToF-SIMS and LEIS), for 304L, the results show a deep oxide scale with multi layers and the outer layer is composed of chromium and manganese oxides. Oxide profiles differ in air or steam atmosphere. Fe2O3 oxide is observed but in minor proportion and in all cases no nickel is detected near the surface. Results obtained are discussed and compared with the literature data.

  14. Intergranular Corrosion Behavior of Low-Nickel and 304 Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Bansod, Ankur V.; Patil, Awanikumar P.; Moon, Abhijeet P.; Khobragade, Nilay N.

    2016-09-01

    Intergranular corrosion (IGC) susceptibility for Cr-Mn austenitic stainless steel and 304 austenitic stainless steel (ASS) was estimated using electrochemical techniques. Optical and SEM microscopy studies were carried out to investigate the nature of IGC at 700 °C with increasing time (15, 30, 60, 180, 360, 720, 1440 min) according to ASTM standard 262 A. Quantitative analysis was performed to estimate the degree of sensitization (DOS) using double loop electrochemical potentiokinetic reactivation (DLEPR) and EIS technique. DLEPR results indicated that with the increase in thermal aging duration, DOS becomes more severe for both types of stainless steel. The DOS for Cr-Mn ASS was found to be higher (65.12% for 1440 min) than that of the AISI 304 ASS (23% for 1440 min). The higher degree of sensitization resulted in lowering of electrical charge capacitance resistance. Chronoamperometry studies were carried out at a passive potential of 0.4 V versus SCE and was observed to have a higher anodic dissolution of the passive film of Cr-Mn ASS. EDS studies show the formation of chromium carbide precipitates in the vicinity of the grain boundary. The higher Mn content was also observed for Cr-Mn ASS at the grain boundary.

  15. Mechanical properties and oxidation and corrosion resistance of reduced-chromium 304 stainless steel alloys

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Barrett, C. A.; Gyorgak, C. A.

    1979-01-01

    An experimental program was undertaken to identify effective substitutes for part of the Cr in 304 stainless steel as a method of conserving the strategic element Cr. Although special emphasis was placed on tensile properties, oxidation and corrosion resistance were also examined. Results indicate that over the temperature range of -196 C to 540 C the yield stress of experimental austenitic alloys with only 12 percent Cr compare favorably with the 18 percent Cr in 304 stainless steel. Oxidation resistance and in most cases corrosion resistance for the experimental alloys were comparable to the commercial alloy. Effective substitutes for Cr included Al, Mo, Si, Ti, and V, while Ni and Mn contents were increased to maintain an austenitic structure.

  16. Intergranular Corrosion Behavior of 304LN Stainless Steel Heat Treated at 623 K (350 °C)

    NASA Astrophysics Data System (ADS)

    Singh, Raghuvir; Kumar, Mukesh; Ghosh, Mainak; Das, Gautam; Singh, P. K.; Chattoraj, I.

    2013-01-01

    Low temperature sensitization of 304LN stainless steel from the two pipes, differing slightly in chemical composition, has been investigated; specimens were aged at 623 K (350 °C) for 20,000 hours and evaluated for intergranular corrosion and degree of sensitization. The base and heat-affected zone (HAZ) of the 304LN-1 appear resistant to sensitization, while 304LN-2 revealed a "dual" type microstructure at the transverse section and HAZ. The microstructure at 5.0-mm distance from the fusion line indicates qualitatively less sensitization as compared to that at 2.0 mm. The 304LN-2 base alloy shows overall lower degree of sensitization values as compared to the 304LN-1. A similar trend of degree of sensitization was observed in the HAZ where it was higher in the 304LN-1 as compared to the 304LN-2. The weld zone of both the stainless steels suffered from cracking during ASTM A262 practice E, while the parent metals and HAZs did not show such fissures. A mottled image within the ferrite lamella showed spinodal decomposition. The practice E test and transmission electron microscopy results indicate that the interdendritic regions may suffer from failure due to carbide precipitation and due to the evolution of brittle phase from spinodal decomposition.

  17. High temperature oxidation behavior of austenitic stainless steel AISI 304 in steam of nanofluids contain nanoparticle ZrO2

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id; Syarif, Dani Gustaman, E-mail: djokohp@batan.go.id

    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} ismore » 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.« less

  18. No corrosion of 304 stainless steel implant after 40 years of service.

    PubMed

    Blackwood, D J; Pereira, B P

    2004-07-01

    When exposed to 0.9% NaCl type 304 stainless steel undergoes severe pitting corrosion within a matter of days. However, a Sherman plate fabricated from type 304 stainless steel remained inside a patient's arm for almost 40 years without any visible indications of corrosion. Given the previous understanding of the pathological environments this was considered quite remarkable. It is proposed that the low dissolved oxygen levels found in human-body fluids makes the long-term in vivo environment much more benign than would be anticipated from in vitro experiments. Furthermore, it is proposed that previous cases of localized pitting corrosion on stainless steel implants most likely arose due to the development of short-term aggressive conditions due to pathological changes in the surrounding tissue as a result of the trauma of the implant procedure. In the present case the Sherman plate was sufficiently small that the surrounding tissue was not aggravated sufficiently to lead to the development of such an environment aggressive. The conclusion that surgical implants are at most risk during the first few weeks of service implies that short-term corrosion protection methods, such as coatings, may be more effective than previously thought.

  19. Microstructure and Shear Strength in Brazing Joint of Mo-Cu Composite with 304 Stainless Steel by Ni-Cr-P Filler Metal

    NASA Astrophysics Data System (ADS)

    Wang, Juan; Wang, Jiteng; Li, Yajiang; Zheng, Deshuang

    2015-07-01

    The brazing of Mo-Cu composite and 304 stainless steel was carried out in vacuum with Ni-Cr-P filler metal at 980 °C for 20 min. Microstructure in Mo-Cu/304 stainless steel joint was investigated by field-emission scanning electron microscope (FE-SEM) with energy dispersive spectrometer (EDS) and shear strength was measured by shearing test. The results indicate that shear strength of the Mo-Cu/304 stainless steel joint is about 155 MPa. There forms eutectic structure of γ-Ni solid solution with Ni3P in the braze seam. Ni-Cu(Mo) and Ni-Fe solid solution are at the interface beside Mo-Cu composite and 304 stainless steel, respectively. Shear fracture exhibits mixed ductile-brittle fracture feature with trans-granular fracture, ductile dimples and tearing edges. Fracture originates from the interface between brazing seam and Mo-Cu composite and it propagates to the braze seam due to the formation of brittle Ni5P2 and Cr3P precipitation.

  20. Microstructural characterization in dissimilar friction stir welding between 304 stainless steel and st37 steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jafarzadegan, M.; State Key Laboratory of Advanced Welding Production Technology, School of Materials Science and Eng., Harbin Institute of Technology, P.O. Box: 150001, Harbin; Feng, A.H.

    2012-12-15

    In the present study, 3 mm-thick plates of 304 stainless steel and st37 steel were welded together by friction stir welding at a welding speed of 50 mm/min and tool rotational speed of 400 and 800 rpm. X-ray diffraction test was carried out to study the phases which might be formed in the welds. Metallographic examinations, and tensile and microhardness tests were used to analyze the microstructure and mechanical properties of the joint. Four different zones were found in the weld area except the base metals. In the stir zone of the 304 stainless steel, a refined grain structure withmore » some features of dynamic recrystallization was evidenced. A thermomechanically-affected zone was characterized on the 304 steel side with features of dynamic recovery. In the other side of the stir zone, the hot deformation of the st37 steel in the austenite region produced small austenite grains and these grains transformed to fine ferrite and pearlite and some products of displacive transformations such as Widmanstatten ferrite and martensite by cooling the material after friction stir welding. The heat-affected zone in the st37 steel side showed partially and fully refined microstructures like fusion welding processes. The recrystallization in the 304 steel and the transformations in the st37 steel enhanced the hardness of the weld area and therefore, improved the tensile properties of the joint. - Highlights: Black-Right-Pointing-Pointer FSW produced sound welds between st37 low carbon steel and 304 stainless steel. Black-Right-Pointing-Pointer The SZ of the st37 steel contained some products of allotropic transformation. Black-Right-Pointing-Pointer The material in the SZ of the 304 steel showed features of dynamic recrystallization. Black-Right-Pointing-Pointer The finer microstructure in the SZ increased the hardness and tensile strength.« less

  1. The effects of surface pretreatment and nitrogen tetroxide purification on the corrosion rate of Type 304L stainless steel

    NASA Technical Reports Server (NTRS)

    Blue, G. D.; Moran, C. M.

    1985-01-01

    Corrosion rates of 304L stainless steel coupons in MON-1 oxidizer have been measured as a function of cleaning procedures employed, surface layer positions, propellant impurity levels, and short-term exposure durations (14 to 90 days). Of special interest was propellant contamination by buildup of soluble iron, which may cause flow decay. Surface treatments employed were combinations of cleaning, pickling, and passivation procedures. Propellants used were MIL-SPEC MON-1 and several types of purified NTO (i.e., low water, low chloride) which may, at a later time, be specified as spacecraft grade. Pretest coupon surface analysis by X-ray photoelectron spectroscopy (XPS-ESCA) has revealed important differences, for the different cleaning procedures, in the make-up of the surface layer, both in composition and state of chemical combination of the elements involved. Comparisons will be made of XPS/ESCA data, for different cleaning procedures, for specimens before and after propellant exposure.

  2. Effect of A-TIG Welding Process on the Weld Attributes of Type 304LN and 316LN Stainless Steels

    NASA Astrophysics Data System (ADS)

    Vasudevan, M.

    2017-03-01

    The specific activated flux has been developed for enhancing the penetration performance of TIG welding process for autogenous welding of type 304LN and 316LN stainless steels through systematic study. Initially single-component fluxes were used to study their effect on depth of penetration and tensile properties. Then multi-component activated flux was developed which was found to produce a significant increase in penetration of 10-12 mm in single-pass TIG welding of type 304LN and 316LN stainless steels. The significant improvement in penetration achieved using the activated flux developed in the present work has been attributed to the constriction of the arc and as well as reversal of Marangoni flow in the molten weld pool. The use of activated flux has been found to overcome the variable weld penetration observed in 316LN stainless steel with <50 ppm of sulfur. There was no degradation in the microstructure and mechanical properties of the A-TIG welds compared to that of the welds produced by conventional TIG welding on the contrary the transverse strength properties of the 304LN and 316LN stainless steel welds produced by A-TIG welding exceeded the minimum specified strength values of the base metals. Improvement in toughness values were observed in 316LN stainless steel produced by A-TIG welding due to refinement in the weld microstructure in the region close to the weld center. Thus, activated flux developed in the present work has greater potential for use during the TIG welding of structural components made of type 304LN and 316LN stainless steels.

  3. Weld pool development during GTA and laser beam welding of Type 304 stainless steel; Part II-experimental correlation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zacharia, T.; David, S.A.; Vitek, J.M.

    1989-12-01

    In part I of the paper, the results of the heat flow and the fluid flow analysis were presented. Here, in Part II of the paper, predictions of the computational model are verified by comparing the numerically predicted and experimentally observed fusion zone size and shape. Stationary gas tungsten arc and laser beam welds were made on Type 304 stainless steel for different times to provide a variety of solidification conditions such as cooling rate and temperature gradient. Calculated temperatures and cooling rates are correlated with the experimentally observed fusion zone structure. In addition, the effect of sulfur on GTAmore » weld penetration was quantitatively evaluated by considering two heats of 304 stainless steel containing 90 and 240 ppm sulfur. Sulfur, as expected, increased the depth/width ratio by altering the surface tension gradient driven flow in the weld pool.« less

  4. Correlation between evolution of inclusions and pitting corrosion in 304 stainless steel with yttrium addition.

    PubMed

    Shi, Weining; Yang, Shufeng; Li, Jingshe

    2018-03-19

    Effects of the evolution of inclusions on the pitting corrosion resistance of 304 stainless steel with different contents of the rare-earth element yttrium (Y) were studied using thermodynamic calculations, accelerated immersion tests, and electrochemical measurements. The experimental results showed that regular Y 2 O 3 inclusions demonstrated the best pitting resistance, followed in sequence by (Al,Mn)O inclusions, the composite inclusions, and irregular Y 2 O 3 inclusions. The pitting resistance first decreased, then increased, and then decreased again with increasing Y content, because sulfide inclusions were easily generated when the Y content was low and YN inclusions were easily generated at higher Y contents. The best pitting corrosion resistance was obtained for 304 stainless steel with addition of 0.019% Y.

  5. Investigation of high temperature corrosion behavior on 304L austenite stainless steel in corrosive environments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sahri, M. I.; Othman, N. K.; Samsu, Z.

    2014-09-03

    In this work, 304L stainless steel samples were exposed at 700 °C for 10hrs in different corrosive environments; dry oxygen, molten salt, and molten salt + dry oxygen. The corrosion behavior of samples was analyzed using weight change measurement technique, optical microscope (OM) and Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray (EDX). The existence phases of corroded sample were determined using X-ray Diffraction (XRD). The lowest corrosion rate was recorded in dry oxygen while the highest was in molten salt + dry oxygen environments with the value of 0.0062 mg/cm{sup 2} and −13.5225 mg/cm{sup 2} respectively. The surfacemore » morphology of sample in presence of salt mixture showed scale spallation. Oxide scales of Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3} were the main phases developed and detected by XRD technique. Cr{sub 2}O{sub 3} was not developed in every sample as protective layers but chromate-rich oxide was developed. The cross-section analysis found the oxide scales were in porous, thick and non-adherent that would not an effective barrier to prevent from further degradation of alloy. EDX analysis also showed the Cr-element was low compared to Fe-element at the oxide scale region.« less

  6. Microbially Influenced Corrosion of 304 Stainless Steel and Titanium by P. variotii and A. niger in Humid Atmosphere

    NASA Astrophysics Data System (ADS)

    Zhang, Dawei; Zhou, Feichi; Xiao, Kui; Cui, Tianyu; Qian, Hongchong; Li, Xiaogang

    2015-07-01

    Microbially induced corrosion (MIC) poses significant threats to reliability and safety of engineering materials and structures. While most MIC studies focus on prokaryotic bacteria such as sulfate-reducing bacteria, the influence of fungi on corrosion behaviors of metals has not been adequately reported. In this study, 304 stainless steel and titanium were exposed to two very common fungi, Paecilomyces variotii, Aspergillus niger and their mixtures under highly humid atmosphere. The initial corrosion behaviors within 28 days were studied via scanning Kelvin probe, which showed marked surface ennoblement and increasingly heterogeneous potential distribution upon prolonged fungus exposure. Using stereomicroscopy, fungus growth as well as corrosion morphology of 304 stainless steel and titanium were also evaluated after a long-term exposure for 60 days. The presence of fungi decreased the corrosion resistance for both 304 stainless steel and titanium. Titanium showed higher resistance to fungus growth and the induced corrosion. Exposure to the mixed strains resulted in the highest fungus growth rate but the mildest corrosion, possibly due to the decreased oxygen level by increased fungal activities.

  7. High Temperature Fuel Cladding Chemical Interactions Between TRIGA Fuels and 304 Stainless Steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Perez, Emmanuel; Keiser, Jr., Dennis D.; Forsmann, Bryan

    High-temperature fuel-cladding chemical interactions (FCCI) between TRIGA (Training, Research, Isotopes, General Atomics) fuel elements and the 304 stainless steel (304SS) are of interest to develop an understanding of the fuel behavior during transient reactor scenarios. TRIGA fuels are composed of uranium (U) particles dispersed in a zirconium-hydride (Zr-H) matrix. In reactor, the fuel is encased in 304-stainless-steel (304SS) or Incoloy 800 clad tubes. At high temperatures, the fuel can readily interact with the cladding, resulting in FCCI. A number of FCCI can take place in this system. Interactions can be expected between the cladding and the Zr-H matrix, and/or betweenmore » the cladding and the U-particles. Other interactions may be expected between the Zr-H matrix and the U-particles. Furthermore, the fuel contains erbium-oxide (Er-O) additions. Interactions can also be expected between the Er-O, the cladding, the Zr-H and the U-particles. The overall result is that very complex interactions may take place as a result of fuel and cladding exposures to high temperatures. This report discusses the characterization of the baseline fuel microstructure in the as-received state (prior to exposure to high temperature), characterization of the fuel after annealing at 950C for 24 hours and the results from diffusion couple experiments carries out at 1000C for 5 and 24 hours. Characterization was carried out via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with sample preparation via focused ion beam in situ-liftout-technique.« less

  8. Influence of low-temperature nitriding on the strain-induced martensite and laser-quenched austenite in a magnetic encoder made from 304L stainless steel.

    PubMed

    Leskovšek, Vojteh; Godec, Matjaž; Kogej, Peter

    2016-08-05

    We have investigated the possibility of producing a magnetic encoder by an innovative process. Instead of turning grooves in the encoder bar for precise positioning, we incorporated the information in 304L stainless steel by transforming the austenite to martensite after bar extrusion in liquid nitrogen and marking it with a laser, which caused a local transformation of martensite back into austenite. 304L has an excellent corrosion resistance, but a low hardness and poor wear resistance, which limits its range of applications. However, nitriding is a very promising way to enhance the mechanical and magnetic properties. After low-temperature nitriding at 400 °C it is clear that both ε- and α'-martensite are present in the deformed microstructure, indicating the simultaneous stress-induced and strain-induced transformations of the austenite. The effects of a laser surface treatment and the consequent appearance of a non-magnetic phase due to the α' → γ transformation were investigated. The EDS maps show a high concentration of nitrogen in the alternating hard surface layers of γN and α'N (expanded austenite and martensite), but no significantly higher concentration of chromium or iron was detected. The high surface hardness of this nitride layer will lead to steels and encoders with better wear and corrosion resistance.

  9. Influence of low-temperature nitriding on the strain-induced martensite and laser-quenched austenite in a magnetic encoder made from 304L stainless steel

    PubMed Central

    Leskovšek, Vojteh; Godec, Matjaž; Kogej, Peter

    2016-01-01

    We have investigated the possibility of producing a magnetic encoder by an innovative process. Instead of turning grooves in the encoder bar for precise positioning, we incorporated the information in 304L stainless steel by transforming the austenite to martensite after bar extrusion in liquid nitrogen and marking it with a laser, which caused a local transformation of martensite back into austenite. 304L has an excellent corrosion resistance, but a low hardness and poor wear resistance, which limits its range of applications. However, nitriding is a very promising way to enhance the mechanical and magnetic properties. After low-temperature nitriding at 400 °C it is clear that both ε- and α′-martensite are present in the deformed microstructure, indicating the simultaneous stress-induced and strain-induced transformations of the austenite. The effects of a laser surface treatment and the consequent appearance of a non-magnetic phase due to the α′ → γ transformation were investigated. The EDS maps show a high concentration of nitrogen in the alternating hard surface layers of γN and α′N (expanded austenite and martensite), but no significantly higher concentration of chromium or iron was detected. The high surface hardness of this nitride layer will lead to steels and encoders with better wear and corrosion resistance. PMID:27492862

  10. Effect of heat input on the microstructure, residual stresses and corrosion resistance of 304L austenitic stainless steel weldments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Unnikrishnan, Rahul, E-mail: rahulunnikrishnannair@gmail.com; Idury, K.S.N. Satish, E-mail: satishidury@gmail.com; Ismail, T.P., E-mail: tpisma@gmail.com

    Austenitic stainless steels are widely used in high performance pressure vessels, nuclear, chemical, process and medical industry due to their very good corrosion resistance and superior mechanical properties. However, austenitic stainless steels are prone to sensitization when subjected to higher temperatures (673 K to 1173 K) during the manufacturing process (e.g. welding) and/or certain applications (e.g. pressure vessels). During sensitization, chromium in the matrix precipitates out as carbides and intermetallic compounds (sigma, chi and Laves phases) decreasing the corrosion resistance and mechanical properties. In the present investigation, 304L austenitic stainless steel was subjected to different heat inputs by shielded metalmore » arc welding process using a standard 308L electrode. The microstructural developments were characterized by using optical microscopy and electron backscattered diffraction, while the residual stresses were measured by X-ray diffraction using the sin{sup 2}ψ method. It was observed that even at the highest heat input, shielded metal arc welding process does not result in significant precipitation of carbides or intermetallic phases. The ferrite content and grain size increased with increase in heat input. The grain size variation in the fusion zone/heat affected zone was not effectively captured by optical microscopy. This study shows that electron backscattered diffraction is necessary to bring out changes in the grain size quantitatively in the fusion zone/heat affected zone as it can consider twin boundaries as a part of grain in the calculation of grain size. The residual stresses were compressive in nature for the lowest heat input, while they were tensile at the highest heat input near the weld bead. The significant feature of the welded region and the base metal was the presence of a very strong texture. The texture in the heat affected zone was almost random. - Highlights: • Effect of heat input on microstructure

  11. Diffusion bonding of titanium to 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Ghosh, M.; Bhanumurthy, K.; Kale, G. B.; Krishnan, J.; Chatterjee, S.

    2003-11-01

    Diffusion bonding between commercially pure titanium and an austenitic stainless steel (AISI 304) has been carried out in the temperature range of 850-950 °C for 2 h at uniaxial pressure of 3 MPa in vacuum. The microstructure of the diffusion zone has been analysed by optical and scanning electron microscopy (SEM). The interdiffusion of the diffusing species across the interface has been evaluated by electron probe microanalysis (EPMA). The reaction products formed at the interface have been identified by X-ray diffraction technique. It has been observed that the diffusion zone is dominated by the presence of the σ phase close to the stainless steel side and the solid solution of β-Ti (solutes are Fe, Cr and Ni) close to the titanium. The presence of Fe 2Ti and FeTi has been found in the reaction zone. It has been observed that the bond strength (˜222 MPa) is highest for the couple processed at 850 °C and this value decreases with rise in joining temperature. The variation of strength of the transition joints is co-related with the microstructural characteristics of the diffusion zone.

  12. Twinning and martensite in a 304 austenitic stainless steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shen, Yongfeng; Li, Xi; Sun, Xin

    2012-08-30

    The microstructure characteristics and deformation behavior of 304L stainless steel during tensile deformation at two different strain rates have been investigated by means of interrupted tensile tests, electron-backscatter-diffraction (EBSD) and transmission electron microscopy (TEM) techniques. The volume fractions of transformed martensite and deformation twins at different stages of the deformation process were measured using X-ray diffraction method and TEM observations. It is found that the volume fraction of martensite monotonically increases with increasing strain but decreases with increasing strain rate. On the other hand, the volume fraction of twins increases with increasing strain for strain level less than 57%. Beyondmore » that, the volume fraction of twins decreases with increasing strain. Careful TEM observations show that stacking faults (SFs) and twins preferentially occur before the nucleation of martensite. Meanwhile, both {var_epsilon}-martensite and {alpha}{prime}-martensite are observed in the deformation microstructures, indicating the co-existence of stress induced- transformation and strain-induced-transformation. We also discussed the effects of twinning and martensite transformation on work-hardening as well as the relationship between stacking faults, twinning and martensite transformation.« less

  13. Microstructural evolution of type 304 and 316 stainless steels under neutron irradiation at LWR relevant conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tan, Lizhen; Stoller, Roger E.; Field, Kevin G.

    Extension of light water reactors' useful life will expose austenitic internal core components to irradiation damage levels beyond 100 displacements per atom (dpa), which will lead to profound microstructural evolution and consequent degradation of macroscopic properties. Microstructural evolution, including Frank loops, cavities, precipitates, and segregation at boundaries and the resultant radiation hardening in type 304 and 316 stainless steel (SS) variants, were studied in this work via experimental characterization and multiple simulation methods. Experimental data for up to 40 heats of type 304SS and 316SS variants irradiated in different reactors to 0.6–120 dpa at 275–375°C were either generated from thismore » work or collected from literature reports. These experimental data were then combined with models of Frank loop and cavity evolution, computational thermodynamics and precipitation, and ab initio and rate theory integrated radiation-induced segregation models to provide insights into microstructural evolution and degradation at higher radiation doses.« less

  14. Microstructural evolution of type 304 and 316 stainless steels under neutron irradiation at LWR relevant conditions

    DOE PAGES

    Tan, Lizhen; Stoller, Roger E.; Field, Kevin G.; ...

    2015-12-11

    Extension of light water reactors' useful life will expose austenitic internal core components to irradiation damage levels beyond 100 displacements per atom (dpa), which will lead to profound microstructural evolution and consequent degradation of macroscopic properties. Microstructural evolution, including Frank loops, cavities, precipitates, and segregation at boundaries and the resultant radiation hardening in type 304 and 316 stainless steel (SS) variants, were studied in this work via experimental characterization and multiple simulation methods. Experimental data for up to 40 heats of type 304SS and 316SS variants irradiated in different reactors to 0.6–120 dpa at 275–375°C were either generated from thismore » work or collected from literature reports. These experimental data were then combined with models of Frank loop and cavity evolution, computational thermodynamics and precipitation, and ab initio and rate theory integrated radiation-induced segregation models to provide insights into microstructural evolution and degradation at higher radiation doses.« less

  15. Microstructure, Properties and Weldability of Duplex Stainless Steel 2101

    NASA Astrophysics Data System (ADS)

    Ma, Li; Hu, Shengsun; Shen, Junqi

    2017-01-01

    The continuous development of duplex stainless steels (DSSs) is due to their excellent corrosion resistance in aggressive environments and their mechanical strength, which is usually twice of conventional austenitic stainless steels (ASSs). In this paper, a designed lean duplex stainless steel 2101, with the alloy design of reduced nickel content and increased additions of manganese and nitrogen, is studied by being partly compared with typical ASS 304L steels. The microstructure, mechanical properties, impact toughness, corrosion resistance and weldability of the designed DSS 2101 were conducted. The results demonstrated that both 2101 steel and its weldment show excellent mechanical properties, impact toughness and corrosion resistance, so DSS 2101 exhibits good comprehensive properties and can be used to replace 304L in numerous applications.

  16. Elevated temperature ductility of types 304 and 316 stainless steel. [640/sup 0/ to 750/sup 0/C

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sikka, V. K.

    1978-01-01

    Austenitic stainless steel types 304 and 316 are known for their high ductility and toughness. However, the present study shows that certain combinations of strain rate and test temperature can result in a significant loss in elevated-temperature ductility. Such a phenomenon is referred to as ductility minimum. The strain rate, below which ductility loss is initiated, decreases with decrease in test temperature. Besides strain rate and temperature, the ductility minimum was also affected by nitrogen content and thermal aging conditions. Thermal aging at 649/sup 0/C was observed to eliminate the ductility minimum at 649/sup 0/C in both types 304 andmore » 316 stainless steel. Such an aging treatment resulted in a higher ductility than the unaged value. Aging at 593/sup 0/C still resulted in some loss in ductility. Current results suggest that ductility-minimum conditions for stainless steel should be considered in design, thermal aging data analysis, and while studying the effects of chemical composition.« less

  17. Effect of Isothermal Hold on the Microstructural Evolution of the Stainless Steel 304L/Zircaloy-4 Interface

    NASA Astrophysics Data System (ADS)

    Lebaili, A.; Taouinet, M.; Nibou, D.; Lebaili, S.; Hodaj, F.

    2017-07-01

    The transition from solid-state bonding of the stainless steel 304L/Zircaloy-4 diffusion couple to a partial liquid-phase bonding is important for the bonding process at temperatures ranging from 950 to 1050 °C. In this study, the temperature at which a melting process occurs at the interface after 45 min of isothermal holdings is determined experimentally. This melting process leads to a drastic change in the thickness of the reaction products zone (RPZ) as well as on its microstructure. Diffusion couples were characterized by SEM-EDS, and quantitative chemical analyses of different phases are performed by EPMA. The RPZ consists of three layers: the (α-Fe-Cr) phase layer and two layers consisting of Zr(Fe,Cr)2 (ɛ), Zr2(Fe,Ni) and (α-Zr) phases. The thickness of these layers strongly depends on the holding temperature. The analysis allowed the description of the physicochemical phenomena occurring during isothermal holding as well as during cooling. The solidification paths are determined at 1000, 1020 and 1050 °C. Hardness tests are performed on the bonded samples in order to qualify the mechanical properties of different phases of the RPZ. This study leads to a better understanding of the complex phenomena intervening in the joining process which is very useful for applications in industrial scale.

  18. Study of the corrosion behaviors of 304 austenite stainless steel specimens exposed to static liquid lithium at 600 K

    NASA Astrophysics Data System (ADS)

    Meng, Xiancai; Zuo, Guizhong; Ren, Jun; Xu, Wei; Sun, Zhen; Huang, Ming; Hu, Wangyu; Hu, Jiansheng; Deng, Huiqiu

    2016-11-01

    Investigation of corrosion behavior of stainless steel served as one kind of structure materials exposed to liquid lithium (Li) is one of the keys to apply liquid Li as potential plasma facing materials (PFM) or blanket coolant in the fusion device. Corrosion experiments of 304 austenite stainless steel (304 SS) were carried out in static liquid Li at 600 K and up to1584 h at high vacuum with pressure less than 4 × 10-4 Pa. After exposure to liquid Li, it was found that the weight of 304 SS slightly decreased with weight loss rate of 5.7 × 10-4 g/m2/h and surface hardness increased by about 50 HV. Lots of spinel-like grains and holes were observed on the surface of specimens measured by SEM. By further EDS, XRD and metallographic analyzing, it was confirmed that the main compositions of spinel-like grains were M23C6 carbides, and 304 SS produced a non-uniform corrosion behavior by preferential grain boundary attack, possibly due to the easy formation of M23C6 carbides and/or formation of Li compound at grain boundaries.

  19. Mechanical Behaviour of 304 Austenitic Stainless Steel Processed by Room Temperature Rolling

    NASA Astrophysics Data System (ADS)

    Singh, Rahul; Goel, Sunkulp; Verma, Raviraj; Jayaganthan, R.; Kumar, Abhishek

    2018-03-01

    To study the effect of room temperature rolling on mechanical properties of 304 Austenitic Stainless Steel, the as received 304 ASS was rolled at room temperature for different percentage of plastic deformation (i.e. 30, 50, 70 and 90 %). Microstructural study, tensile and hardness tests were performed in accordance with ASTM standards to study the effect of rolling. The ultimate tensile strength (UTS) and hardness of a rolled specimen have enhanced with rolling. The UTS has increased from 693 MPa (as received) to 1700 MPa (after 90% deformation). The improvement in UTS of processed samples is due to combined effect of grain refinement and stress induced martensitic phase transformation. The hardness values also increases from 206 VHN (as received) to 499 VHN (after 90% deformation). Magnetic measurements were also conducted to confirm the formation of martensitic phase.

  20. Microelectrode Array Microscopy: Investigation of Dynamic Behavior of Localized Corrosion at Type 304 Stainless Steel Surfaces

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tedd E. Lister; Patrick J. Pinhero

    2005-03-01

    Scanning electrochemical microscopy (SECM) and a recently developed microelectrode array microscope have been used to study localized corrosion and electron-transfer characteristics of native oxide layers of type 304 stainless steels. The I-/I3- redox couple was employed as a mediator and allowed sensitive detection of oxide breakdown events. In solutions containing I-, a signal at the microelectrode was observed on type 304 stainless steel surfaces at active pitting corrosion sites. Under conditions where pitting corrosion occurs, SECM was used to track the temporal characteristics of the reaction in a spatial manner. However, because of the time required to create an image,more » much of the temporal information was not obtained. To improve the temporal resolution of the measurement, microelectrode array microscopy (MEAM) was developed as a parallel method of performing SECM. The demonstration shown reveals the potential of MEAM for analysis of surface chemistry on temporal and spatial domains.« less

  1. Characterization and study of mechanical and tribological properties on titanium di oxide (TiO2) coated 304L stainless steel

    NASA Astrophysics Data System (ADS)

    Ghanaraja, S.; Ali, Syed Imran; Ravikumar, K. S.; Likith, P.

    2018-04-01

    In the present investigation Atmospheric Plasma Spraying (APS) method is selected for coating the materials on 304L Stainless Steel as a substrate material, also called as substrate of Thermal Barrier Coating (TBC) system developed in the present work. Commercially available Ni-Cr metal powder is selected for bond coat and TiO2 powder is selected for Top Coat. The thickness of bond coat is taken as 75 µm where as the top coat thickness is varied as 100 µm, 200 µm and 300 µm. In plasma sprayed coating more attention is given to obtain uniform thickness on the given substrate. The various surface texture parameters of each sample is tested, morphology and coating thickness of above TBC system are studied with the help of SEM and X-Ray Diffraction for phase analysis. Micro-hardness of each layer of coating is measured by using Vicker's diamond indentation and the abrasive wear resistance of each system has been investigated through Pin-on-disc test, at room temperature by using wear and friction tribometer. The coating system possesses good wear resistance and can be used in various applications.

  2. Laser surface alloying of FeCoCrAlNi high-entropy alloy on 304 stainless steel to enhance corrosion and cavitation erosion resistance

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Wu, C. L.; Zhang, C. H.; Guan, M.; Tan, J. Z.

    2016-10-01

    FeCoCrAlNi high-entropy alloy coating was synthesized with premixed high-purity Co, Cr, Al and Ni powders on 304 stainless steel by laser surface alloying, aiming at improving corrosion and cavitation erosion resistance. Phase constituents, microstructure and microhardness were investigated using XRD, SEM, and microhardness tester, respectively. The cavitation erosion and electrochemical corrosion behavior of FeCoCrAlNi coating in 3.5% NaCl solution were also evaluated using an ultrasonic vibrator and potentiodynamic polarization measurement. Experimental results showed that with appropriate laser processing parameters, FeCoCrAlNi coating with good metallurgical bonding to the substrate could be achieved. FeCoCrAlNi coating was composed of a single BCC solid solution. The formation of simple solid solutions in HEAs was the combined effect of mixing entropy (ΔSmix), mixing enthalpy (ΔHmix), atom-size difference (δ) and valence electron concentration (VEC), and the effect of ΔSmix was much larger than that of the other factors. The microhardness of the FeCoCrAlNi coating was ~3 times that of the 304 stainless steel. Both the corrosion and cavitation erosion resistance of the coating were improved. The cavitation erosion resistance for FeCoCrAlNi HEA coating was ~7.6 times that of 304 stainless steel. The corrosion resistance was also improved as reflected by a reduction in the current density of one order of magnitude as compared with 304 stainless steel.

  3. 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.

  4. An Investigation into Stress Corrosion Cracking of Dissimilar Metal Welds with 304L Stainless Steel and Alloy 82 in High Temperature Pure Water

    NASA Astrophysics Data System (ADS)

    Yeh, Tsung-Kuang; Huang, Guan-Ru; Tsai, Chuen-Horng; Wang, Mei-Ya

    For a better understanding toward stress corrosion cracking (SCC) in dissimilar metal welds with 304L stainless steel and Alloy 82, the SCC growth behavior in the transition regions of weld joints was investigated via slow strain rate tensile (SSRT) tests in 280 oC pure water with a dissolve oxygen level of 300 ppb. Prior to the SSRT tests, samples with dissimilar metal welds were prepared and underwent various pretreatments, including post-weld heat treatment (PWHT), shot peening, solution annealing, and mechanical grinding. In addition to the SSRT tests, measurements of degree of sensitization and micro-hardness on the transition regions of the metal welds were also conducted. According to the test results, the samples having undergone PWHTs exhibited relatively high degrees of sensitization. Distinct decreases in hardness were observed in the heat-affected zones of the base metals in all samples. Furthermore, the fracture planes of all samples after the SSRT tests were located at the stainless steel sides and were in parallel with the fusion lines. Among the treating conditions investigated in this study, a PWHT would pose a detrimental effect on the samples in the aspects of mechanical property and degree of SCC. Solution annealing would lead to the greatest improvement in ductility and SCC retardation, and shot peening would provide the treated samples with a positive improvement in ductility and corrosion retardation, but not to a great extent.

  5. Results of inphase axial-torsional fatigue experiments on 304 stainless steel

    NASA Technical Reports Server (NTRS)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1989-01-01

    A series of axial-torsional, inphase, strain-controlled, low-cycle fatigue tests were performed at room temperature on tubular specimens of 304 stainless steel. The program was conducted in cooperation with the task group on multiaxial fatigue research of ASTM committee E-09. The objective was to quantify the variability in multiaxial test results among several laboratories. Only included is data which was generated at the NASA Lewis Research Center's High Temperature Fatigue and Structures Laboratory. The experimental equipment and procedures used are described. The tubular specimens were polished on the outer surface to aid in the use of a cellulose film surface replication technique for crack detection. However, cracking initiated predominantly on the internal surface for all specimens. Honing of the bore of the tubular specimens lessened but did not entirely eliminate this problem. The observed fatigue lives are compared with lives calculated from three multiaxial life models. Constants for the life prediction models were obtained from uniaxial and torsional tests performed on the same heat of material. The observed fatigue lives agreed with calculated lives to within a factor of two for all but one of the life prediction models.

  6. Biofilm formation by Listeria monocytogenes on stainless steel surface and biotransfer potential.

    PubMed

    de Oliveira, Maíra Maciel Mattos; Brugnera, Danilo Florisvaldo; Alves, Eduardo; Piccoli, Roberta Hilsdorf

    2010-01-01

    An experimental model was proposed to study biofilm formation by Listeria monocytogenes ATCC 19117 on AISI 304 (#4) stainless steel surface and biotransfer potential during this process. In this model, biofilm formation was conducted on the surface of stainless steel coupons, set on a stainless steel base with 4 divisions, each one supporting 21 coupons. Trypic Soy Broth was used as bacterial growth substrate, with incubation at 37 °C and stirring of 50 rpm. The number of adhered cells was determined after 3, 48, 96, 144, 192 and 240 hours of biofilm formation and biotransfer potential from 96 hours. Stainless steel coupons were submitted to Scanning Electron Microscopy (SEM) after 3, 144 and 240 hours. Based on the number of adhered cells and SEM, it was observed that L. monocytogenes adhered rapidly to the stainless steel surface, with mature biofilm being formed after 240 hours. The biotransfer potential of bacterium to substrate occurred at all the stages analyzed. The rapid capacity of adhesion to surface, combined with biotransfer potential throughout the biofilm formation stages, make L. monocytogenes a potential risk to the food industry. Both the experimental model developed and the methodology used were efficient in the study of biofilm formation by L. monocytogenes on stainless steel surface and biotransfer potential.

  7. Defect sink characteristics of specific grain boundary types in 304 stainless steels under high dose neutron environments

    DOE PAGES

    Field, Kevin G.; Yang, Ying; Busby, Jeremy T.; ...

    2015-03-09

    Radiation induced segregation (RIS) is a well-studied phenomena which occurs in many structurally relevant nuclear materials including austenitic stainless steels. RIS occurs due to solute atoms preferentially coupling to mobile point defect fluxes that migrate and interact with defect sinks. Here, a 304 stainless steel was neutron irradiated up to 47.1 dpa at 320 °C. Investigations into the RIS response at specific grain boundary types were utilized to determine the sink characteristics of different boundary types as a function of irradiation dose. A rate theory model built on the foundation of the modified inverse Kirkendall (MIK) model is proposed andmore » benchmarked to the experimental results. This model, termed the GiMIK model, includes alterations in the boundary conditions based on grain boundary structure and includes expressions for interstitial binding. This investigation, through experiment and modeling, found specific grain boundary structures exhibit unique defect sink characteristics depending on their local structure. Furthermore, such interactions were found to be consistent across all doses investigated and had larger global implications including precipitation of Ni-Si clusters near different grain boundary types.« less

  8. Nonlinear ultrasonic assessment of stress corrosion cracking damage in sensitized 304 stainless steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Morlock, Florian, E-mail: fmorlock3@gatech.edu; Jacobs, Laurence J., E-mail: fmorlock3@gatech.edu; Kim, Jin-Yeon, E-mail: fmorlock3@gatech.edu

    2015-03-31

    This research uses nonlinear Rayleigh surface waves to characterize stress corrosion cracking (SCC) damage in welded 304 Stainless Steel (304 SS). 304 SS is widely used in reactor pressure vessels, where a corrosive environment in combination with applied stress due to high internal pressures can cause SCC. Welds and the nearby heat affected zones (HAZ) in the vessel material are especially sensitive to SCC damage. SCC damage results in microstructural changes such as dislocation formation and microcrack initiation that in the long term lead to reduced structural integrity and material failure. Therefore, the early detection of SCC is crucial tomore » ensure safe operation. It has been shown that the microstructural changes caused by SCC can generate higher harmonic waves when excited harmonically. This research considers different levels of SCC damage induced in samples of welded 304 SS by applying stress to a specimen held in a corrosive medium (Sodium Thiosulfate). A nonlinear Rayleigh surface wave is introduced in the material and the fundamental and the second harmonic waves are measured using wedge detection. The nonlinearity parameter that relates the fundamental and the second harmonic amplitudes, is computed to quantify the SCC damage in each sample. These results are used to demonstrate the feasibility of using nonlinear Rayleigh waves to characterize SCC damage.« less

  9. Friction Welding For Cladding Applications: Processing, Microstructure and Mechanical Properties of Inertia Friction Welds of Stainless Steel to Low Carbon Steel and Evaluation of Wrought and Welded Austenitic Stainless Steels for Cladding Applications in Acidchloride Service

    NASA Astrophysics Data System (ADS)

    Switzner, Nathan

    Friction welding, a solid-state joining method, is presented as a novel alternative process step for lining mild steel pipe and forged components internally with a corrosion resistant (CR) metal alloy for petrochemical applications. Currently, fusion welding is commonly used for stainless steel overlay cladding, but this method is costly, time-consuming, and can lead to disbonding in service due to a hard martensite layer that forms at the interface due to partial mixing at the interface between the stainless steel CR metal and the mild steel base. Firstly, the process parameter space was explored for inertia friction butt welding using AISI type 304L stainless steel and AISI 1018 steel to determine the microstructure and mechanical properties effects. A conceptual model for heat flux density versus radial location at the faying surface was developed with consideration for non-uniform pressure distribution due to frictional forces. An existing 1 D analytical model for longitudinal transient temperature distribution was modified for the dissimilar metals case and to account for material lost to the flash. Microstructural results from the experimental dissimilar friction welds of 304L stainless steel to 1018 steel were used to discuss model validity. Secondly, the microstructure and mechanical property implications were considered for replacing the current fusion weld cladding processes with friction welding. The nominal friction weld exhibited a smaller heat softened zone in the 1018 steel than the fusion cladding. As determined by longitudinal tensile tests across the bond line, the nominal friction weld had higher strength, but lower apparent ductility, than the fusion welds due to the geometric requirements for neck formation adjacent to a rigid interface. Martensite was identified at the dissimilar friction weld interface, but the thickness was smaller than that of the fusion welds, and the morphology was discontinuous due to formation by a mechanism of solid

  10. Corrosion resistance of kolsterised austenitic 304 stainless steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Abudaia, F. B., E-mail: fabudaia@yahoo.com; Khalil, E. O., E-mail: ekhalil9@yahoo.com; Esehiri, A. F., E-mail: Hope-eseheri@hotmail.co.uk

    2015-03-30

    Austenitic stainless suffers from low wear resistance in applications where rubbing against other surfaces is encountered. This drawback can be overcome by surface treatment such as coating by hard materials. Other treatments such as carburization at relatively low temperature become applicable recently to improve hardness and wear resistance. Carburization heat treatment would only be justified if the corrosion resistance is unaffected. In this work samples of 304 stainless steels treated by colossal supersaturation case carburizing (known as Kolsterising) carried out by Bodycote Company was examined for pitting corrosion resistance at room temperature and at 50 °C. Comparison with results obtainedmore » for untreated samples in similar testing conditions show that there is no deterioration in the pitting resistance due to the Kolsterising heat treatment. X ray diffraction patterns obtained for Kolsterising sample showed that peaks correspond to the austenite phase has shifted to lower 2θ values compared with those of the untreated sample. The shift is an indication for expansion of austenite unit cells caused by saturation with diffusing carbon atoms. The XRD of Kolsterising samples also revealed additional peaks appeared in the patterns due to formation of carbides in the kolsterised layer. Examination of these additional peaks showed that these peaks are attributed to a type of carbide known as Hagg carbide Fe{sub 2}C{sub 5}. The absence of carbides that contain chromium means that no Cr depletion occurred in the layer and the corrosion properties are maintained. Surface hardness measurements showed large increase after Kolsterising heat treatment.« less

  11. Gravitational effects on weld pool shape and microstructural evolution during gas tungsten arc and laser beam welding on 304 stainless steel, nickel, and aluminum-4 wt.% copper alloy

    NASA Astrophysics Data System (ADS)

    Kang, Namhyun

    The objective of the present work was to investigate effects of gravitational (acceleration) level and orientation on Ni 200 alloy (99.5% Ni purity), 304 stainless steel, and Al-4 wt.% Cu alloy during gas tungsten arc welding (GTAW) and laser beam welding (LBW). Main characterization was focused on the weld pool shape, microstructure, and solute distribution as a function of gravitational level and orientation. The welds were divided into two classes, i.e., 'stable' and 'unstable' welds, in view of the variation of weld pool shape as a function of gravitational level and orientation. In general, higher arc current and translational GTAW produced more significant effects of gravitational orientation on the weld pool shape than the case of lower arc current and spot welding. Cross-sectional area (CSA) was a secondary factor in determining the stability of weld pool shape. For the 'stable' weld of 304 stainless steel GTAW, the II-U weld showed less convexity in the pool bottom and more depression of the free surface, therefore producing deeper penetration (10--20%) than the case of II-D weld. The II-D weld of 304 stainless steel showed 31% deeper penetration, 28% narrower width, and more hemispherical shape of the weld pool than the case of II-U weld. For GTAW on 304 stainless steel, gravitational level variation from low gravity (LG ≈ 1.2 go) to high gravity (HG ≈ 1.8 go) caused 10% increase in width and 10% decrease in depth while maintaining the overall weld pool volume. Furthermore, LBW on 304 stainless steels showed mostly constant shape of weld pool as a function of gravitational orientation. GTAW on Ni showed similar trends of weld pool shape compared with GTAW on 304 stainless steel, i.e., the weld pool became unstable by showing more penetration in the II-D weld for slower arc translational velocity (V a) and larger weld pool size. However, the Ni weld pool shape had greater stability of the weld pool shape with respect to the gravitational orientation

  12. Influence of injected interstitials on the void swelling in two structural variants of 304L stainless steel induced by self-ion irradiation at 500 °C

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sun, C.; Garner, F. A.; Shao, L.

    The two variants of AISI 304L stainless steel (SS) with different grain size distributions were ion irradiated at 500 °C to a peak dose of ~60 dpa. In the coarse-grained annealed variant, a peak swelling of ~12% was observed closer to the specimen surface rather than at the depth of peak displacement damage. The forward shift in depth between peak swelling and peak dose is proposed to be a consequence of suppression of void nucleation by injected interstitials. The swelling behavior in the front portion of the ion range mirrors that of neutron-induced swelling in this steel, exhibiting significant curvaturemore » with increasing dose as the swelling rate approaches the terminal swelling rate of 1%/dpa. Furthermore, an ultrafine grain variant of this steel produced by severely plastic deformation exhibits a similar suppression of void nucleation in the injected interstitial region, but also shows a significantly extended transient regime, not reaching the terminal swelling rate by 60 dpa.« less

  13. Influence of injected interstitials on the void swelling in two structural variants of 304L stainless steel induced by self-ion irradiation at 500 °C

    DOE PAGES

    Sun, C.; Garner, F. A.; Shao, L.; ...

    2017-03-28

    The two variants of AISI 304L stainless steel (SS) with different grain size distributions were ion irradiated at 500 °C to a peak dose of ~60 dpa. In the coarse-grained annealed variant, a peak swelling of ~12% was observed closer to the specimen surface rather than at the depth of peak displacement damage. The forward shift in depth between peak swelling and peak dose is proposed to be a consequence of suppression of void nucleation by injected interstitials. The swelling behavior in the front portion of the ion range mirrors that of neutron-induced swelling in this steel, exhibiting significant curvaturemore » with increasing dose as the swelling rate approaches the terminal swelling rate of 1%/dpa. Furthermore, an ultrafine grain variant of this steel produced by severely plastic deformation exhibits a similar suppression of void nucleation in the injected interstitial region, but also shows a significantly extended transient regime, not reaching the terminal swelling rate by 60 dpa.« less

  14. Preparation and characterization of 304 stainless steel/Q235 carbon steel composite material

    NASA Astrophysics Data System (ADS)

    Shen, Wenning; Feng, Lajun; Feng, Hui; Cao, Ying; Liu, Lei; Cao, Mo; Ge, Yanfeng

    The composite material of 304 stainless steel reinforced Q235 carbon steel has been prepared by modified hot-rolling process. The resulted material was characterized by scanning electron microscope, three-electrode method, fault current impact method, electrochemical potentiodynamic polarization curve measurement and electrochemical impedance spectroscopy. The results showed that metallurgical bond between the stainless steel layer and carbon steel substrate has been formed. The composite material exhibited good electrical conductivity and thermal stability. The average grounding resistance of the composite material was about 13/20 of dip galvanized steel. There has no surface crack and bubbling formed after fault current impact. The composite material led to a significant decrease in the corrosion current density in soil solution, compared with that of hot dip galvanized steel and bare carbon steel. On the basis polarization curve and EIS analyses, it can be concluded that the composite material showed improved anti-corrosion property than hot-dip galvanized steel.

  15. Systematic study of polycrystalline flow during tension test of sheet 304 austenitic stainless steel at room temperature

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Muñoz-Andrade, Juan D., E-mail: jdma@correo.azc.uam.mx

    2013-12-16

    By systematic study the mapping of polycrystalline flow of sheet 304 austenitic stainless steel (ASS) during tension test at constant crosshead velocity at room temperature was obtained. The main results establish that the trajectory of crystals in the polycrystalline spatially extended system (PCSES), during irreversible deformation process obey a hyperbolic motion. Where, the ratio between the expansion velocity of the field and the velocity of the field source is not constant and the field lines of such trajectory of crystals become curved, this accelerated motion is called a hyperbolic motion. Such behavior is assisted by dislocations dynamics and self-accommodation processmore » between crystals in the PCSES. Furthermore, by applying the quantum mechanics and relativistic model proposed by Muñoz-Andrade, the activation energy for polycrystalline flow during the tension test of 304 ASS was calculated for each instant in a global form. In conclusion was established that the mapping of the polycrystalline flow is fundamental to describe in an integral way the phenomenology and mechanics of irreversible deformation processes.« less

  16. Systematic study of polycrystalline flow during tension test of sheet 304 austenitic stainless steel at room temperature

    NASA Astrophysics Data System (ADS)

    Muñoz-Andrade, Juan D.

    2013-12-01

    By systematic study the mapping of polycrystalline flow of sheet 304 austenitic stainless steel (ASS) during tension test at constant crosshead velocity at room temperature was obtained. The main results establish that the trajectory of crystals in the polycrystalline spatially extended system (PCSES), during irreversible deformation process obey a hyperbolic motion. Where, the ratio between the expansion velocity of the field and the velocity of the field source is not constant and the field lines of such trajectory of crystals become curved, this accelerated motion is called a hyperbolic motion. Such behavior is assisted by dislocations dynamics and self-accommodation process between crystals in the PCSES. Furthermore, by applying the quantum mechanics and relativistic model proposed by Muñoz-Andrade, the activation energy for polycrystalline flow during the tension test of 304 ASS was calculated for each instant in a global form. In conclusion was established that the mapping of the polycrystalline flow is fundamental to describe in an integral way the phenomenology and mechanics of irreversible deformation processes.

  17. Effects of scan rate on the corrosion behavior SS 304 stainless steel in the nanofluid measured by Tafel polarization methods

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Prajitno, Djoko Hadi

    The Effects of scan rate on the Tafel polarization curve that is obtained to determine corrosion rate are conducted. The tafel polarization curves are obtained at different scan rates for Stainless Steel 304 in nanofluids contain 0.01 gpl nano particle ZrO{sub 2}. The corrosion stainless steel in nanofluid contains adm+0.01 gpl ZrO{sub 2} nanoparticles at different scan rate was performed by Tafel polarization. The results show that according corrosion potential examination of the stainless steel in nanofluid media 0.01gpl ZrO{sub 2} nanoparticle was actively corroded. The value of cathodic Tafel slope stainless steel in nanofluid at different scan rate relativelymore » unchanged after polarization testing. Mean while the value of anodic Tafel slope stainless steel in nanofluid increase at different scan rate. The results of Tafel polarization technique show that corrosion rate of stainless steel in nanofluid increase with increasing scan rate. X ray diffraction examination of stainless steel after Tafel polarization depict that γ Fe phase is major phase in the surface of alloy.« less

  18. Evaluation of AISI Type 304 stainless steel as a suitable surface material for evaluating the efficacy of peracetic acid-based disinfectants against Clostridium difficile spores.

    PubMed

    Black, Elaine; Owens, Krista; Staub, Richard; Li, Junzhong; Mills, Kristen; Valenstein, Justin; Hilgren, John

    2017-01-01

    Disinfectants play an important role in controlling microbial contamination on hard surfaces in hospitals. The effectiveness of disinfectants in real life can be predicted by laboratory tests that measure killing of microbes on carriers. The modified Quantitative Disk Carrier Test (QCT-2) is a standard laboratory method that employs American Iron and Steel Institute (AISI) Type 430 stainless steel carriers to measure hospital disinfectant efficacy against Clostridium difficile spores. The formation of a rust-colored precipitate was observed on Type 430 carriers when testing a peracetic acid (PAA)-based disinfectant with the QCT-2 method. It was hypothesized that the precipitate was indicative of corrosion of the Type 430 carrier, and that corrosion could impact efficacy results. The objective of this study was to compare the suitability of AISI Type 430 to Type 304 stainless steel carriers for evaluating PAA-based disinfectants using the QCT-2 method. Type 304 is more corrosion-resistant than Type 430, is ubiquitous in healthcare environments, and is used in other standard methods. Suitability of the carriers was evaluated by comparing their impacts on efficacy results and PAA degradation rates. In efficacy tests with 1376 ppm PAA, reductions of C. difficile spores after 5, 7 and 10 minutes on Type 430 carriers were at least about 1.5 log10 lower than reductions on Type 304 carriers. In conditions simulating a QCT-2 test, PAA concentration with Type 430 carriers was reduced by approximately 80% in 10 minutes, whereas PAA concentration in the presence of Type 304 carriers remained stable. Elemental analyses of residues on each carrier type after efficacy testing were indicative of corrosion on the Type 430 carrier. Use of Type 430 stainless steel carriers for measuring the efficacy of PAA-based disinfectants should be avoided as it can lead to an underestimation of real life sporicidal efficacy. Type 304 stainless steel carriers are recommended as a suitable

  19. Evaluation of AISI Type 304 stainless steel as a suitable surface material for evaluating the efficacy of peracetic acid-based disinfectants against Clostridium difficile spores

    PubMed Central

    Owens, Krista; Staub, Richard; Li, Junzhong; Mills, Kristen; Valenstein, Justin; Hilgren, John

    2017-01-01

    Disinfectants play an important role in controlling microbial contamination on hard surfaces in hospitals. The effectiveness of disinfectants in real life can be predicted by laboratory tests that measure killing of microbes on carriers. The modified Quantitative Disk Carrier Test (QCT-2) is a standard laboratory method that employs American Iron and Steel Institute (AISI) Type 430 stainless steel carriers to measure hospital disinfectant efficacy against Clostridium difficile spores. The formation of a rust-colored precipitate was observed on Type 430 carriers when testing a peracetic acid (PAA)-based disinfectant with the QCT-2 method. It was hypothesized that the precipitate was indicative of corrosion of the Type 430 carrier, and that corrosion could impact efficacy results. The objective of this study was to compare the suitability of AISI Type 430 to Type 304 stainless steel carriers for evaluating PAA-based disinfectants using the QCT-2 method. Type 304 is more corrosion-resistant than Type 430, is ubiquitous in healthcare environments, and is used in other standard methods. Suitability of the carriers was evaluated by comparing their impacts on efficacy results and PAA degradation rates. In efficacy tests with 1376 ppm PAA, reductions of C. difficile spores after 5, 7 and 10 minutes on Type 430 carriers were at least about 1.5 log10 lower than reductions on Type 304 carriers. In conditions simulating a QCT-2 test, PAA concentration with Type 430 carriers was reduced by approximately 80% in 10 minutes, whereas PAA concentration in the presence of Type 304 carriers remained stable. Elemental analyses of residues on each carrier type after efficacy testing were indicative of corrosion on the Type 430 carrier. Use of Type 430 stainless steel carriers for measuring the efficacy of PAA-based disinfectants should be avoided as it can lead to an underestimation of real life sporicidal efficacy. Type 304 stainless steel carriers are recommended as a suitable

  20. Investigation on localized corrosion of 304 stainless steel joints brazed using Sn-plated Ag alloy filler in NaCl aqueous solution

    NASA Astrophysics Data System (ADS)

    Wang, Xingxing; Li, Shuai; Peng, Jin

    2018-03-01

    Novel AgCuZnSn filler metal with high Sn contents was prepared from BAg50CuZn filler metal by a process of electroplating and thermal diffusion, and the prepared filler metal was applied to induction brazing of 304 stainless steel. The corrosion behavior of the brazed joints was evaluated based on localized corrosion analysis, the morphology of the joints were analyzed by SEM after immersion in a 3.5 vol% NaCl aqueous solution. The results indicated that corrosion groove occurred near the interface between the stainless steel base metal and the brazing seam. A wide range of defects such as holes and cracks appeared on the surface of the base metal, while the brazing seam zone almost no corrosion defects occur. With the increase of corrosion time, the corrosion rates of both the brazing seam and the base metal first exhibited an increasing trend, followed by a decreasing trend, and the corrosion rate of the base metal was slightly greater than that of the brazing seam. The corrosion potential of the brazing seam and 304 stainless steel were -0.7758 V and -0.7863 V, respectively.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shibata, K.; Ogata, T.; Nyilas, A.

    2006-03-31

    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 initiatedmore » 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.« less

  2. Fatigue limit and Hysteresis Behavior of Type 304L Stainless Steel in Air and PWR Water, at 150°C and 300°C

    NASA Astrophysics Data System (ADS)

    Solomon, H. D.; Amzallag, C.; Vallee, A. J.; DeLair, R. E.

    This is a study of the 107 cycle fatigue limit of Type 304L Stainless Steel, as measured in fully reversed (R=-1) load-controlled tests, at 150°C and 300°C, in air and PWR water. The staircase method was used to determine the fatigue limit. The tests run here utilized a cycle frequency of 1.818Hz and are compared to other tests from the literature that were run at 30Hz. The fatigue limit measured in the tests run at the high frequency was higher than that measured here. This is explained by measurements of the strain developed during cycling, using the different cycle frequencies. The tests run at the higher frequencies yielded lower strains for a given stress and, as expected, this resulted in higher fatigue limits. Using 107 cycles to define a run-out also led to a lower fatigue limit. These results are important as most previous fatigue limit measurements utilized 106 cycles or less to define a run-out, and when lives as long as 107 cycles are used the tests are generally run at high cycle frequencies, thus leading to higher fatigue limits than those measured here.

  3. Effects of beam offset on mechanical properties and corrosion resistance of Alloy 690-SUS 304L EBW joints for nuclear power plant

    NASA Astrophysics Data System (ADS)

    Lin, Yong-Ding; Lee, Hwa-Teng; Kuo, Tsung-Yuan; Jeng, Sheng-Long; Wu, Jia-Lin

    2010-06-01

    The current study investigates the effect of the beam offset (BOF) on the microstructure, mechanical properties, and the corrosion resistance of the fusion zone (FZ) of Alloy 690-SUS 304L stainless steel (SS) dissimilar metal butt joints formed by electron beam welding (EBW). The experimental results showed that as the value of the BOF increased from 0 to 0.30 mm, i.e. the electron beam shifted progressively toward the Alloy 690 base metal (BM), the tensile strength of the FZ fell from 582.1 to 541.2 MPa. However, the modified Huey test results indicated that the interdendritic corrosion resistance of the FZ was significantly enhanced. Pit nucleation potential value ( Enp) was raised from 385 to 1050 mV. An offset of 0.30 mm appears to be the optimal BOF setting when fabricating Alloy 690-SUS 304L SS dissimilar metal butt joints using the EBW technique.

  4. Facile fabrication of superhydrophobic surfaces from austenitic stainless steel (AISI 304) by chemical etching

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Hun; Mirzaei, Ali; Kim, Hyoun Woo; Kim, Sang Sub

    2018-05-01

    Stainless steels are among the most common engineering materials and are used extensively in humid areas. Therefore, it is important that these materials must be robust to humidity and corrosion. This paper reports the fabrication of superhydrophobic surfaces from austenitic stainless steel (type AISI 304) using a facile two-step chemical etching method. In the first step, the stainless steel plates were etched in a HF solution, followed by a fluorination process, where they showed a water contact angle (WCA) of 166° and a sliding angle of 5° under the optimal conditions. To further enhance the superhydrophobicity, in the second step, they were dipped in a 0.1 wt.% NaCl solution at 100 °C, where the WCA was increased to 168° and the sliding angle was decreased to ∼2°. The long-term durability of the fabricated superhydrophobic samples for 1 month storage in air and water was investigated. The potential applicability of the fabricated samples was demonstrated by the excellent superhydrophobicity after 1 month. In addition, the self-cleaning properties of the fabricated superhydrophobic surface were also demonstrated. This paper outlines a facile, low-cost and scalable chemical etching method that can be adopted easily for large-scale purposes.

  5. Corrosion of stainless steels in lead-bismuth eutectic up to 600 °C

    NASA Astrophysics Data System (ADS)

    Soler, L.; Martín, F. J.; Hernández, F.; Gómez-Briceño, D.

    2004-11-01

    An experimental program has been carried out to understand the differences in the corrosion behaviour between different stainless steels: the austenitic steels 304L and 316L, the martensitic steels F82Hmod, T91 and EM10, and the low alloy steel P22. The influence of oxygen level in Pb-Bi, temperature and exposure time is studied. At 600 °C, the martensitic steels and the P22 steel exhibit thick oxide scales that grow with time, following a linear law for the wet environment and a parabolic law for the dry one. The austenitic stainless steels show a better corrosion behaviour, especially AISI 304L. Under reducing conditions, the steels exhibit dissolution, more severe for the austenitic stainless steels. At 450 °C, all the materials show an acceptable behaviour provided a sufficient oxygen level in the Pb-Bi. At reducing conditions, the martensitic steels and the P22 steel have a good corrosion resistance, while the austenitic steels exhibit already dissolution at the longer exposures.

  6. Sintered Intermetallic Reinforced 434L Ferritic Stainless Steel Composites

    NASA Astrophysics Data System (ADS)

    Upadhyaya, A.; Balaji, S.

    2009-03-01

    The present study examines the effect of aluminide (Ni3Al, Fe3Al) additions on the sintering behavior of ferritic 434L stainless steels during solid-state sintering (SSS) and supersolidus liquid-phase sintering (SLPS). 434L stainless steel matrix composites containing 5 and 10 wt pct of each aluminide were consolidated at 1200 °C (SSS) and 1400 °C (SLPS). The effects of sintering and aluminide additions on the densification, microstructural evolution, mechanical, tribological, and corrosion behavior of sintered ferritic (434L) stainless steels were investigated. The performances of the 434L-aluminide composites were compared with the straight 434L stainless steels processed at similar conditions. Supersolidus sintering resulted in significant improvement in densification, mechanical, wear, and corrosion resistance in both straight 434L and 434L-aluminide composites. Fe3Al additions to 434L stainless steels result in improved wear resistance without significant degradation of corrosion resistance in 3.56 wt pct NaCl solution.

  7. Analysis of AISI 304 Tensile Strength as an Anchor Chain of Mooring System

    NASA Astrophysics Data System (ADS)

    Hamidah, I.; Wati, R.; Hamdani, R. A.

    2018-05-01

    The background of this research is the use of mild steel (i.e., St37) as anchor chain that works on the corrosive environment of seawater which is possible to decrease its tensile strength. The longer soaked in seawater, the more significant the lowering of its tensile strength. Anchor chain needs to be designed by considering its tensile strength and corrosion resistance, so it’s able to support mooring system well. The primary purpose of this research is obtaining the decreasing of stainless steel 304 (AISI 304) tensile strength which is corroded by seawater as anchor chain of the mooring system. It is also essential to obtain the lifetime of AISI304 and St37 as anchor chain with the same load, the corrosion rate of AISI 304, and St 37 in seawater. The method which was employed in this research is an experiment with four pieces of stainless steel AISI 304, and of St 37 corrosion testing samples, six pieces of stainless steel 304, and six pieces of St 37 for tensile testing samples. The result of this research shows that seawater caused stainless steel AISI 304 as anchor chain has decreased of tensile strength about 1.68 % during four weeks. Also, it indicates that AISI 304 as anchor chain has a lifetime about 130 times longer than St 37. Further, we found that the corrosion rate of stainless steel 304 in seawater is 0.2042 mpy in outstanding category, while the St 37 samples reached up to 27.0247 mpy ranked as fair category. This result recommends that AISI 304 more excellence than St 37 as anchor chain of the mooring system.

  8. 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.

  9. Electrodeposition of Ni(OH)2 reinforced polyaniline coating for corrosion protection of 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Jiang, Li; Syed, Junaid Ali; Gao, Yangzhi; Lu, Hongbin; Meng, Xiangkang

    2018-05-01

    In the present paper, polyaniline (PANI) coating was electropolymerized in the presence of phosphoric acid with subsequent deposition of Ni(OH)2 particles. The Ni(OH)2 reinforced PANI coating significantly enhances the corrosion resistance of 304 stainless steel (304SS) in comparison with the pristine PANI coating. The galvanostatically deposited Ni(OH)2 particles fill the pores of the pristine PANI coating and improves the coatings hydrophobicity which decreases the diffusion of aggressive media. Importantly, the Rp values of Ni(OH)2 reinforced PANI coating is much higher than that of pristine PANI coating and the Ni(OH)2 reinforced PANI coating presents a long-term anti-corrosive ability (360 h) in 3.5 wt% NaCl solution. The prolonged corrosion protection of Ni(OH)2 reinforced PANI coating is attributed to the improved physical barrier as well as the facile formation of passive oxide film that sustain the anodic protection of the coating.

  10. Microstructure and Mechanical Properties of Dissimilar Friction Stir Spot Welding Between St37 Steel and 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Khodadadi, Ali; Shamanian, Morteza; Karimzadeh, Fathallah

    2017-05-01

    In the present study, St37 low-carbon steel and 304 stainless steel were welded successfully, with the thickness of 2 mm, by a friction stir spot welding process carried out at the tool dwell time of 6 s and two different tool rotational speeds of 630 and 1250 rpm. Metallographic examinations revealed four different zones including SZ and HAZ areas of St37 steel and SZ and TMAZ regions of 304 stainless steel in the weld nugget, except the base metals. X-ray diffraction and energy-dispersive x-ray spectroscopy experiments were used to investigate the possible formation of such phases as chromium carbide. Based on these experiments, no chromium carbide precipitation was found. The recrystallization of the weld nugget in the 304 steel and the phase transformations of the weld regions in the St37 steel enhanced the hardness of the weld joint. Hardness changes of joint were acceptable and approximately uniform, as compared to the resistance spot weld. In this research, it was also observed that the tensile/shear strength, as a crucial factor, was increased with the rise in the tool rotational speed. The bond length along the interface between metals, as an effective parameter to increase the tensile/shear strength, was also determined. At higher tool rotational speeds, the bond length was found to be improved, resulting in the tensile/shear strength of 6682 N. Finally, two fracture modes were specified through the fracture mode analysis of samples obtained from the tensile/shear test consisting of the shear fracture mode and the mixed shear/tensile fracture mode.

  11. Corrosion Resistance of Stainless Steels in Biodiesel

    NASA Astrophysics Data System (ADS)

    Román, Alejandra S.; Méndez, Claudia M.; Ares, Alicia E.

    The aim of this work was to study the corrosion behavior of stainless steels in biodiesel of vegetal origin, at room temperature, evaluating its properties according to the differences in the structures (austenitic, ferritic and austenitic — ferritic) and compositions of the materials. The biodiesel employed was obtained by industrially manufactured based on soybean oil as main raw material. The stainless steels used as samples for the tests were: AISI 304L, Sea Cure and Duplex 2205. For obtaining the desired data potentiodynamic polarization and weight loss trials were carried out. These studies were complemented by observations using an optical microscope. The weight loss study allowed the identification of low corrosion rates to the three stainless steels studied.

  12. Microstructural characterization and density change of 304 stainless steel reflector blocks after long-term irradiation in EBR-II

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Wiezorek, J. M. K.; Garner, F. A.; Freyer, P. D.; Okita, T.; Sagisaka, M.; Isobe, Y.; Allen, T. R.

    2015-10-01

    While thin reactor structural components such as cladding and ducts do not experience significant gradients in dpa rate, gamma heating rate, temperature or stress, thick components can develop strong local variations in void swelling and irradiation creep in response to gradients in these variables. In this study we conducted microstructural investigations by transmission electron microscopy of two 52 mm thick 304-type stainless steel hex-blocks irradiated for 12 years in the EBR-II reactor with accumulated doses ranging from ∼0.4 to 33 dpa. Spatial variations in the populations of voids, precipitates, Frank loops and dislocation lines have been determined for 304 stainless steel sections exposed to different temperatures, different dpa levels and at different dpa rates, demonstrating the existence of spatial gradients in the resulting void swelling. The microstructural measurements compare very well with complementary density change measurements regarding void swelling gradients in the 304 stainless steel hex-block components. The TEM studies revealed that the original cold-worked-state microstructure of the unirradiated blocks was completely erased by irradiation, replaced by high densities of interstitial Frank loops, voids and carbide precipitates at both the lowest and highest doses. At large dose levels the amount of volumetric void swelling correlated directly with the gamma heating gradient-related temperature increase (e.g. for 28 dpa, ∼2% swelling at 418 °C and ∼2.9% swelling at 448 °C). Under approximately iso-thermal local conditions, volumetric void swelling was found to increase with dose level (e.g. ∼0.2% swelling at 0.4 dpa, ∼0.5% swelling at 4 dpa and ∼2% swelling at 28 dpa). Carbide precipitate formation levels were found to be relatively independent of both dpa level and temperature and induced a measurable densification. Void swelling was dominant at the higher dose levels and caused measurable decreases in density. Void swelling

  13. Enhancement of anticorrosion property of 304 stainless steel using silane coatings

    NASA Astrophysics Data System (ADS)

    Akhtar, Sultan; Matin, Asif; Madhan Kumar, A.; Ibrahim, Ahmed; Laoui, Tahar

    2018-05-01

    In the present work, silane coatings based on glycidoxypropyltrimethoxysilane/methyltrimethoxysilane (GPTMS/MTMS) and silica nanoparticles were prepared by a sol-gel method. A simple dip-coating method was applied for film deposition and the effect of immersion time and number of immersion cycles on corrosion behavior of 304 stainless steel (SS) was investigated. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) was used to study the surface morphology and elemental composition of the modified surfaces. The corrosion behavior of the coated and uncoated SS substrates was studied by potentiodynamic polarization and electrochemical impedance spectroscopy in 0.6 M sodium chloride solution. Our results showed that the presence of coatings improved the anti-corrosion property of SS substrates. The coating with a dipping time of 10 min and 3 dipping cycles exhibited the best protection efficiency compared to other coatings and the uncoated substrate. SEM/EDS findings and contact angle measurements supported the conclusions drawn from the corrosion study.

  14. The effect of inhibitor sodium nitrate on pitting corrosion of dissimilar material weldment joint of stainless steel AISI 304 and mild steel SS 400

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hilca, B. R., E-mail: bangkithilca@yahoo.com; Triyono, E-mail: triyonomesin@uns.ac.id

    This study experimentally evaluated the effect of Sodium Nitrate inhibitor (NaNO{sub 3}) of 0.1%, 0.3%, and 0.5% on NaCl 3.5% toward pitting corrosion of dissimilar metal welding joint between stainless steel AISI 304 and mild steel SS 400. Electrochemical corrosion was tested using potentiodynamic polarization. Further the Scanning Electron Microscope (SEM) conducted to analyze the specimen. Chemical composition analysis used Energy Dispersive X-ray Spectrometry (EDS). The highest efficiency of sodium nitrate for ER 308 attained 63.8% and 64.89%for ER 309L. The specimen surface which observed through SEM showed decrease of pitting corrosion respectively with the addition of sodium nitrate contentmore » as inhibitor.« less

  15. A numerical study of multiple adiabatic shear bands evolution in a 304LSS thick-walled cylinder

    NASA Astrophysics Data System (ADS)

    Liu, Mingtao; Hu, Haibo; Fan, Cheng; Tang, Tiegang

    2017-01-01

    The self-organization of multiple shear bands in a 304L stainless steel(304LSS) thick-walled cylinder (TWC) was numerically studied. The microstructures of material lead to the non-uniform distribution of the local yield stress, which play a key role in the formation of spontaneous shear localization. We introduced a probability factor satisfied the Gaussian distribution into the macroscopic constitutive relationship to describe the non-uniformity of local yield stress. Using the probability factor, the initiation and propagation of multiple shear bands in TWC were numerically replicated in our 2D FEM simulation. Experimental results in the literature indicated that the machined surface at the internal boundary of a 304L stainless steel cylinder provides a work-hardened layer (about 20˜30μm) which has significantly different microstructures from the base material. The work-hardened layer leads to the phenomenon that most shear bands propagate along a given direction, clockwise or counterclockwise. In our simulation, periodical single direction spiral perturbations were applied to describe the grain orientation in the work-hardened layer, and the single direction spiral pattern of shear bands was successfully replicated.

  16. 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.

  17. Coupling mechanism between wear and oxidation processes of 304 stainless steel in hydrogen peroxide environments.

    PubMed

    Dong, Conglin; Yuan, Chengqing; Bai, Xiuqin; Li, Jian; Qin, Honglin; Yan, Xinping

    2017-05-24

    Stainless steel is widely used in strongly oxidizing hydrogen peroxide (H 2 O 2 ) environments. It is crucial to study its wear behaviour and failure mode. The tribological properties and oxidation of 304 stainless steel were investigated using a MMW-1 tribo-tester with a three-electrode setup in H 2 O 2 solutions with different concentrations. Corrosion current densities (CCDs), coefficients of frictions (COFs), wear mass losses, wear surface topographies, and metal oxide films were analysed and compared. The results show that the wear process and oxidation process interacted significantly with each other. Increasing the concentration of H 2 O 2 or the oxidation time was useful to form a layer of integrated, homogeneous, compact and thick metal oxide film. The dense metal oxide films with higher mechanical strengths improved the wear process and also reduced the oxidation reaction. The wear process removed the metal oxide films to increase the oxidation reaction. Theoretical data is provided for the rational design and application of friction pairs in oxidation corrosion conditions.

  18. Relationships Between the Phase Transformation Kinetics, Texture Evolution, and Microstructure Development in a 304L Stainless Steel Under Biaxial Loading Conditions: Synchrotron X-ray and Electron Backscatter Diffraction Studies

    DOE PAGES

    Cakmak, Ercan; Choo, Hahn; Kang, Jun-Yun; ...

    2015-02-11

    Here we report that the relationships between the martensitic phase transformation kinetics, texture evolution, and the microstructure development in the parent austenite phase were studied for a 304L stainless steel that exhibits the transformation-induced plasticity effect under biaxial loading conditions at ambient temperature. The applied loading paths included: pure torsion, simultaneous biaxial torsion/tension, simultaneous biaxial torsion/compression, and stepwise loading of tension followed by torsion (i.e., first loading by uniaxial tension and then by pure torsion in sequence). Synchrotron X-ray and electron backscatter diffraction techniques were used to measure the evolution of the phase fractions, textures, and microstructures as a functionmore » of the applied strains. The influence of loading character and path on the changes in martensitic phase transformation kinetics is discussed in the context of (1) texture-transformation relationship and the preferred transformation of grains belonging to certain texture components over the others, (2) effects of axial strains on shear band evolutions, and (3) volume changes associated with martensitic transformation.« less

  19. Relationships Between the Phase Transformation Kinetics, Texture Evolution, and Microstructure Development in a 304L Stainless Steel Under Biaxial Loading Conditions: Synchrotron X-ray and Electron Backscatter Diffraction Studies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cakmak, Ercan; Choo, Hahn; Kang, Jun-Yun

    2015-02-11

    The relationships between the martensitic phase transformation kinetics, texture evolution, and the microstructure development in the parent austenite phase were studied for a 304L stainless steel that exhibits the transformation-induced plasticity effect under biaxial loading conditions at ambient temperature. The applied loading paths included: pure torsion, simultaneous biaxial torsion/tension, simultaneous biaxial torsion/compression, and stepwise loading of tension followed by torsion (i.e., first loading by uniaxial tension and then by pure torsion in sequence). Synchrotron X-ray and electron backscatter diffraction techniques were used to measure the evolution of the phase fractions, textures, and microstructures as a function of the applied strains.more » The influence of loading character and path on the changes in martensitic phase transformation kinetics is discussed in the context of (1) texture-transformation relationship and the preferred transformation of grains belonging to certain texture components over the others, (2) effects of axial strains on shear band evolutions, and (3) volume changes associated with martensitic transformation.« less

  20. Analytical and Electrochemical Study of Passive Films in Stainless Steels Subjected to Aqueous Solutions

    NASA Astrophysics Data System (ADS)

    Jahangiribabavi, Negin

    The objective of this research is to study the corrosion behavior of the stainless steel centrifugal contactor used in the spent nuclear fuel treatment process called UREX+ process. AISI type 304L stainless steel was suggested as the material of construction for this contactor. Corrosion of 304L stainless steel in three acidic aqueous solutions of 5.0M HNO3, 5.0M HNO 3 + 0.1M HF, and 5.0M HNO3 + 0.1M HF + 0.1M Zr4+ was studied. Immersion, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) corrosion tests were conducted at test temperatures of 25, 40, and 80°C and three different rotational speeds (0, 1000, 2000 rpm) in order to mimic the operating conditions of the centrifugal contactor. The results showed that the 5.0M HNO3 + 0.1M HF solution was the most corrosive environment as the fluoride ions dissolved the passive film present on the surface of the stainless steel. The addition of 0.1M Zr 4+ ions to this acidic mixture reduced the corrosion caused by HF to levels similar to those found in HNO3 solutions and allowed the stainless steel to preserve its passive film. Further addition of zirconium ion did not result in better corrosion resistance of the stainless steel. Besides, higher corrosion rates were obtained as the solutions temperatures increased while the hydrodynamic conditions had less significant effect on corrosion rates.

  1. Effects of Ultrasonic Nanocrystal Surface Modification on the Residual Stress, Microstructure, and Corrosion Resistance of 304 Stainless Steel Welds

    NASA Astrophysics Data System (ADS)

    Ye, Chang; Telang, Abhishek; Gill, Amrinder; Wen, Xingshuo; Mannava, Seetha R.; Qian, Dong; Vasudevan, Vijay K.

    2018-03-01

    In this study, ultrasonic nanocrystal surface modification (UNSM) of 304 stainless steel welds was carried out. UNSM effectively eliminates the tensile stress generated during welding and imparts beneficial compressive residual stresses. In addition, UNSM can effectively refine the grains and increase hardness in the near-surface region. Corrosion tests in boiling MgCl2 solution demonstrate that UNSM can significantly improve the corrosion resistance due to the compressive residual stresses and changes in the near-surface microstructure.

  2. Effect of Built-Up Edge Formation during Stable State of Wear in AISI 304 Stainless Steel on Machining Performance and Surface Integrity of the Machined Part.

    PubMed

    Ahmed, Yassmin Seid; Fox-Rabinovich, German; Paiva, Jose Mario; Wagg, Terry; Veldhuis, Stephen Clarence

    2017-10-25

    During machining of stainless steels at low cutting -speeds, workpiece material tends to adhere to the cutting tool at the tool-chip interface, forming built-up edge (BUE). BUE has a great importance in machining processes; it can significantly modify the phenomenon in the cutting zone, directly affecting the workpiece surface integrity, cutting tool forces, and chip formation. The American Iron and Steel Institute (AISI) 304 stainless steel has a high tendency to form an unstable BUE, leading to deterioration of the surface quality. Therefore, it is necessary to understand the nature of the surface integrity induced during machining operations. Although many reports have been published on the effect of tool wear during machining of AISI 304 stainless steel on surface integrity, studies on the influence of the BUE phenomenon in the stable state of wear have not been investigated so far. The main goal of the present work is to investigate the close link between the BUE formation, surface integrity and cutting forces in the stable sate of wear for uncoated cutting tool during the cutting tests of AISI 304 stainless steel. The cutting parameters were chosen to induce BUE formation during machining. X-ray diffraction (XRD) method was used for measuring superficial residual stresses of the machined surface through the stable state of wear in the cutting and feed directions. In addition, surface roughness of the machined surface was investigated using the Alicona microscope and Scanning Electron Microscopy (SEM) was used to reveal the surface distortions created during the cutting process, combined with chip undersurface analyses. The investigated BUE formation during the stable state of wear showed that the BUE can cause a significant improvement in the surface integrity and cutting forces. Moreover, it can be used to compensate for tool wear through changing the tool geometry, leading to the protection of the cutting tool from wear.

  3. Effect of Built-Up Edge Formation during Stable State of Wear in AISI 304 Stainless Steel on Machining Performance and Surface Integrity of the Machined Part

    PubMed Central

    Fox-Rabinovich, German; Wagg, Terry

    2017-01-01

    During machining of stainless steels at low cutting -speeds, workpiece material tends to adhere to the cutting tool at the tool–chip interface, forming built-up edge (BUE). BUE has a great importance in machining processes; it can significantly modify the phenomenon in the cutting zone, directly affecting the workpiece surface integrity, cutting tool forces, and chip formation. The American Iron and Steel Institute (AISI) 304 stainless steel has a high tendency to form an unstable BUE, leading to deterioration of the surface quality. Therefore, it is necessary to understand the nature of the surface integrity induced during machining operations. Although many reports have been published on the effect of tool wear during machining of AISI 304 stainless steel on surface integrity, studies on the influence of the BUE phenomenon in the stable state of wear have not been investigated so far. The main goal of the present work is to investigate the close link between the BUE formation, surface integrity and cutting forces in the stable sate of wear for uncoated cutting tool during the cutting tests of AISI 304 stainless steel. The cutting parameters were chosen to induce BUE formation during machining. X-ray diffraction (XRD) method was used for measuring superficial residual stresses of the machined surface through the stable state of wear in the cutting and feed directions. In addition, surface roughness of the machined surface was investigated using the Alicona microscope and Scanning Electron Microscopy (SEM) was used to reveal the surface distortions created during the cutting process, combined with chip undersurface analyses. The investigated BUE formation during the stable state of wear showed that the BUE can cause a significant improvement in the surface integrity and cutting forces. Moreover, it can be used to compensate for tool wear through changing the tool geometry, leading to the protection of the cutting tool from wear. PMID:29068405

  4. High-temperature Chemical Compatibility of As-fabricated TRIGA Fuel and Type 304 Stainless Steel Cladding

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dennis D. Keiser, Jr.; Jan-Fong Jue; Eric Woolstenhulme

    2012-09-01

    Chemical interaction between TRIGA fuel and Type-304 stainless steel cladding at relatively high temperatures is of interest from the point of view of understanding fuel behavior during different TRIGA reactor transient scenarios. Since TRIGA fuel comes into close contact with the cladding during irradiation, there is an opportunity for interdiffusion between the U in the fuel and the Fe in the cladding to form an interaction zone that contains U-Fe phases. Based on the equilibrium U-Fe phase diagram, a eutectic can develop at a composition between the U6Fe and UFe2 phases. This eutectic composition can become a liquid at aroundmore » 725°C. From the standpoint of safe operation of TRIGA fuel, it is of interest to develop better understanding of how a phase with this composition may develop in irradiated TRIGA fuel at relatively high temperatures. One technique for investigating the development of a eutectic phase at the fuel/cladding interface is to perform out-of-pile diffusion-couple experiments at relatively high temperatures. This information is most relevant for lightly irradiated fuel that just starts to touch the cladding due to fuel swelling. Similar testing using fuel irradiated to different fission densities should be tested in a similar fashion to generate data more relevant to more heavily irradiated fuel. This report describes the results for TRIGA fuel/Type-304 stainless steel diffusion couples that were annealed for one hour at 730 and 800°C. Scanning electron microscopy with energy- and wavelength-dispersive spectroscopy was employed to characterize the fuel/cladding interface for each diffusion couple to look for evidence of any chemical interaction. Overall, negligible fuel/cladding interaction was observed for each diffusion couple.« less

  5. Vibration analysis of resistance spot welding joint for dissimilar plate structure (mild steel 1010 and stainless steel 304)

    NASA Astrophysics Data System (ADS)

    Sani, M. S. M.; Nazri, N. A.; Alawi, D. A. J.

    2017-09-01

    Resistance spot welding (RSW) is a proficient joining method commonly used for sheet metal joining and become one of the oldest spot welding processes use in industry especially in the automotive. RSW involves the application of heat and pressure without neglecting time taken when joining two or more metal sheets at a localized area which is claimed as the most efficient welding process in metal fabrication. The purpose of this project is to perform model updating of RSW plate structure between mild steel 1010 and stainless steel 304. In order to do the updating, normal mode finite element analysis (FEA) and experimental modal analysis (EMA) have been carried out. Result shows that the discrepancies of natural frequency between FEA and EMA are below than 10 %. Sensitivity model updating is evaluated in order to make sure which parameters are influences in this structural dynamic modification. Young’s modulus and density both materials are indicate significant parameters to do model updating. As a conclusion, after perform model updating, total average error of dissimilar RSW plate is improved significantly.

  6. Phase formation in selected surface-roughened plasma-nitrided 304 austenite stainless steel.

    PubMed

    Singh, Gajendra Prasad; Joseph, Alphonsa; Raole, Prakash Manohar; Barhai, Prema Kanta; Mukherjee, Subroto

    2008-04-01

    Direct current (DC) glow discharge plasma nitriding was carried out on three selected surface-roughened AISI 304 stainless steel samples at 833 K under 4 mbar pressures for 24 h in the presence of N 2 :H 2 gas mixtures of 50 : 50 ratios. After plasma nitriding, the phase formation, case depth, surface roughness, and microhardness of a plasma-nitrided layer were evaluated by glancing angle x-ray diffractogram, optical microscope, stylus profilometer, and Vickers microhardness tester techniques. The case depth, surface hardness, and phase formation variations were observed with a variation in initial surface roughness. The diffraction patterns of the plasma-nitrided samples showed the modified intensities of the α and γ phases along with those of the CrN, Fe 4 N, and Fe 3 N phases. Hardness and case depth variations were observed with a variation in surface roughness. A maximum hardness of 1058 Hv and a case depth of 95 μm were achieved in least surface-roughened samples.

  7. Creation of superhydrophobic stainless steel surfaces by acid treatments and hydrophobic film deposition.

    PubMed

    Li, Lester; Breedveld, Victor; Hess, Dennis W

    2012-09-26

    In this work, we present a method to render stainless steel surfaces superhydrophobic while maintaining their corrosion resistance. Creation of surface roughness on 304 and 316 grade stainless steels was performed using a hydrofluoric acid bath. New insight into the etch process is developed through a detailed analysis of the chemical and physical changes that occur on the stainless steel surfaces. As a result of intergranular corrosion, along with metallic oxide and fluoride redeposition, surface roughness was generated on the nano- and microscales. Differences in alloy composition between 304 and 316 grades of stainless steel led to variations in etch rate and different levels of surface roughness for similar etch times. After fluorocarbon film deposition to lower the surface energy, etched samples of 304 and 316 stainless steel displayed maximum static water contact angles of 159.9 and 146.6°, respectively. However, etching in HF also caused both grades of stainless steel to be susceptible to corrosion. By passivating the HF-etched samples in a nitric acid bath, the corrosion resistant properties of stainless steels were recovered. When a three step process was used, consisting of etching, passivation and fluorocarbon deposition, 304 and 316 stainless steel samples exhibited maximum contact angles of 157.3 and 134.9°, respectively, while maintaining corrosion resistance.

  8. Underwater laser weld bowing distortion behavior and mechanism of thin 304 stainless steel plates

    NASA Astrophysics Data System (ADS)

    Huang, ZunYue; Luo, Zhen; Ao, Sansan; Cai, YangChuan

    2018-10-01

    Underwater laser weld bowing distortion behavior and mechanism of thin 304 stainless steel plates are studied in the paper. The influence of underwater laser welding parameters (such as laser power, welding speed, defocusing distance and gas flow rate) on weld bowing distortion was investigated through central composite rotatable design and an orthogonal test. A quadratic response model was established to evaluate the underwater laser weld bowing distortion by central composite rotatable design and the order of the impacts of the welding parameters on weld bowing distortion was studied by an orthogonal test. The weld bowing distortion after welding was determined by the digital image correlation technique. The weld bowing distortion of in-air laser welding and underwater laser welding were compared and it revealed that the shape of the in-air and underwater laser welded specimens are the same, but the weld bowing distortion amount of in-air welding is larger than that of underwater welding. Weld bowing distortion mechanism was studied by the digital image correlation technique, and it was demonstrated that weld bowing distortion is associated with the welding plate temperature gradient during laser welding. The wider weld width also resulted in larger weld bowing distortion.

  9. Irradiation-assisted stress corrosion cracking of model austenitic stainless steel.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chung, H. M.; Ruther, W. E.; Strain, R. V.

    1999-10-26

    Slow-strain-rate tensile (SSRT) tests were conducted on model austenitic stainless steel (SS) alloys that were irradiated at 289 C in He. After irradiation to {approx}0.3 x 10{sup 21} n {center_dot} cm{sup 2} and {approx} 0.9 x 10{sup 21} n {center_dot} cm{sup -2} (E > 1 MeV), significant heat-to-heat variations in the degree of intergranular and transgranular stress corrosion cracking (IGSCC and TGSCC) were observed. At {approx}0.3 x 10{sup 21} n {center_dot} cm{sup -2}, a high-purity heat of Type 316L SS that contains a very low concentration of Si exhibited the highest susceptibility to IGSCC. In unirradiated state, Types 304 andmore » 304L SS did not exhibit a systematic effect of Si content on alloy strength. However, at {approx}0.3 x 10{sup 21} n {center_dot} cm{sup -2}, yield and maximum strengths decreased significantly as Si content was increased to >0.9 wt.%. Among alloys that contain low concentrations of C and N, ductility and resistance to TGSCC and IGSCC were significantly greater for alloys with >0.9 wt.% Si than for alloys with <0.47 wt.% Si. Initial data at {approx}0.9 x 10{sup 21} n {center_dot} cm{sup -2} were also consistent with the beneficial effect of high Si content. This indicates that to delay onset of and reduce susceptibility to irradiation-assisted stress corrosion cracking (IASCC), at least at low fluence levels, it is helpful to ensure a certain minimum concentration of Si. High concentrations of Cr were also beneficial; alloys that contain <15.5 wt.% Cr exhibited greater susceptibility to IASCC than alloys with {approx}18 wt.% Cr, whereas an alloy that contains >21 wt.% Cr exhibited less susceptibility than the lower-Cr alloys under similar conditions.« less

  10. Effects of Loading Frequency on Fatigue Behavior, Residual Stress, and Microstructure of Deep-Rolled Stainless Steel AISI 304 at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Nikitin, I.; Juijerm, P.

    2018-02-01

    The effects of loading frequency on the fatigue behavior of non-deep-rolled (NDR) and deep-rolled (DR) austenitic stainless steel AISI 304 were systematically clarified at elevated temperatures, especially at temperatures exhibiting the dynamic strain aging (DSA) phenomena. Tension-compression fatigue tests were performed isothermally at temperatures of 573 K and 773 K (300 °C and 500 °C) with different loading frequencies of 5, 0.5, 0.05, and 0.005 Hz. For the DR condition, the residual stresses and work-hardening states will be presented. It was found that DSA would be detected at appropriate temperatures and deformation rates. The cyclic deformation curves and the fatigue lives of the investigated austenitic stainless steel AISI 304 are considerably affected by the DSA, especially on the DR condition having high dislocation densities at the surface and in near-surface regions. In the temperature range of the DSA, residual stresses and work-hardening states of the DR condition seem to be stabilized. The microstructural alterations were investigated by transmission electron microscopy (TEM). At an appropriate temperature with low loading frequency, the plastic deformation mechanism shifted from a wavy slip manner to a planar slip manner in the DSA regimes, whereas the dislocation movements were obstructed.

  11. The mechanical properties of austenite stainless steel 304 after structural deformation through cold work

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mubarok, Naila; Manaf, Azwar, E-mail: azwar@ui.ac.id; Notonegoro, Hamdan Akbar

    The 304 stainless steel (SS) type is widely used in oil and gas operations due to its excellent corrosion resistance. However, the presence of the fine sand particles and H{sub 2}S gas contained in crude oil could lead the erosion and abrasion in steel. In this study, cold rolled treatments were conducted to the 304 SS in order to increase the wear resistance of the steel. The cold work has resulted in thickness reduction to 20%, 40% and 60% of the original. Various microstructural characterizations were used to analyze the effect of deformation. The hardness characterization showed that the initialmore » hardness value increased from 145 HVC to 395 HVC as the level of deformation increase. Further, the wear resistance increased with the deformation rate from 0% to 40% and subsequently decreased from 40% to 60% deformation rate. Microstructural characterization shows that the boundary change to coincide by 56 µm, 49 µm, 45 µm, and 43 µm width and the grain go to flatten and being folded like needles. The effect of deformation on the grain morphology and structure was also studied by optical metallography and X-Ray Diffraction. It is shown that the deformation by means of a cold rolled process has transformed the austenite structure into martensitic structure.« less

  12. Comparative study: Degree of sensitization and intergranular stress corrosion cracking susceptibility of type 304 stainless steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Muraleedharan, P.; Gnanamoorthy, J.B.; Rodriguez, P.

    1996-10-01

    An attempt was made to correlate the susceptibility of type 304 stainless steel sensitized by isothermal exposures from 500 C to 700 C to intergranular stress corrosion cracking (IGSCC) in boiling 20% sodium chloride solution to the degree of sensitization (DOS) measured using the electrochemical potentiokinetic reactivation (EPR) test. No systematic correlation was detected over the entire time-temperature regime. However, for a given sensitizing temperature, IGSCC susceptibility increased with increasing DOS up to a certain value, with no further increase thereafter. This behavior was attributed to the difference in sensitivities of the EPR and IGSCC tests to chromium depletion atmore » the grain boundaries (GB) during the sensitizing heat treatments.« less

  13. 2014 Accomplishments-Tritium aging studies on stainless steel: Fracture toughness properties of forged stainless steels-Effect of hydrogen, forging strain rate, and forging temperature

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Morgan, Michael J.

    Forged stainless steels are used as the materials of construction for tritium reservoirs. During service, tritium diffuses into the reservoir walls and radioactively decays to helium-3. Tritium and decay helium cause a higher propensity for cracking which could lead to a tritium leak or delayed failure of a tritium reservoir. The factors that affect the tendency for crack formation and propagation include: Environment; steel type and microstructure; and, vessel configuration (geometry, pressure, residual stress). Fracture toughness properties are needed for evaluating the long-term effects of tritium on their structural properties. Until now, these effects have been characterized by measuring themore » effects of tritium on the tensile and fracture toughness properties of specimens fabricated from experimental forgings in the form of forward-extruded cylinders. A key result of those studies is that the long-term cracking resistance of stainless steels in tritium service depends greatly on the interaction between decay helium and the steels’ forged microstructure. New experimental research programs are underway and are designed to measure tritium and decay helium effects on the cracking properties of stainless steels using actual tritium reservoir forgings instead of the experimental forgings of past programs. The properties measured should be more representative of actual reservoir properties because the microstructure of the specimens tested will be more like that of the tritium reservoirs. The programs are designed to measure the effects of key forging variables on tritium compatibility and include three stainless steels, multiple yield strengths, and four different forging processes. The effects on fracture toughness of hydrogen and crack orientation were measured for type 316L forgings. In addition, hydrogen effects on toughness were measured for Type 304L block forgings having two different yield strengths. Finally, fracture toughness properties of type

  14. Correlation of Rupture Life, Creep Rate, and Microstructure for Type 304 Stainless Steel

    NASA Technical Reports Server (NTRS)

    Swindeman, R. W.; Moteff, J.

    1983-01-01

    The stress and temperature sensitivites of the rupture life and secondary creep rate were examined in detail for a single heat of type 304 stainless steel (9T2796). Assuming that the rupture life has a power law stress dependency, relatively small differences in the stress exponent were observed over a broad range of stress and temperature. In contrast, large changes were observed for equivalent parameter for secondary creep rate. As a result of these differences, the Monkman-Grant correlation was sensitive to stress and temperature below 650 C. Metallurgical studies based on light and transmission electron microscopy suggested that the temperature and stress sensitivities of secondary creep rate at temperatures below 650 C were related to features of the substructure not present at higher temperature. Specifically, the presence of a fine dislocation network stabilized by precipitates altered the stress and temperature sensitivities relative to what might be expected from high temperature studies.

  15. Microstructure and Corrosion Behavior of Laser Melted 304L SS Weldment in Nitric Acid Medium

    NASA Astrophysics Data System (ADS)

    Suresh, Girija; Kishor, P. S. V. R. A.; Dasgupta, Arup; Upadhyay, B. N.; Mallika, C.; Kamachi Mudali, U.

    2017-02-01

    The manuscript presents the effect of laser surface melting on the corrosion property of 304L SS weldment in nitric acid medium. 304L SS weldment was prepared by gas tungsten arc welding process and subsequently laser surface melted using Nd:YAG laser. The microstructure and corrosion resistance of laser surface melted 304L SS weldment was evaluated and compared with that of 304L SS as-weldment and 304L SS base. Microstructural evaluation was carried out using optical and scanning electron microscopes attached with energy-dispersive x-ray spectroscopy. Corrosion investigations were carried out in 4 and 8 M nitric acid by potentiodynamic polarization technique. From the results, it was found that laser surface melting of the weldment led to chemical and microstructural homogeneities, accompanied by a substantial decrease in delta ferrite content, that enhanced the corrosion resistance of the weldment in 4 and 8 M nitric acid. However, the enhancement in the corrosion resistance was not substantial. The presence of small amount of delta ferrite (2-4 wt.%) in the laser surface melted specimens was found to be detrimental in nitric acid. X-ray photoelectron spectroscopy studies were carried out to investigate the composition of the passive film.

  16. Gravitational effects on the weld pool shape and microstructural evolution during gas tungsten arc and laser beam welding of 304 stainless steel and Al-4 wt% Cu alloy.

    PubMed

    Kang, Namhyun; Singh, Jogender; Kulkarni, Anil K

    2004-11-01

    Effects of gravitational acceleration were investigated on the weld pool shape and microstructural evolution for 304 stainless steel and Al-4wt% Cu alloy. Effects of welding heat source were investigated by using laser beam welding (LBW) and gas tungsten arc welding (GTAW). As the gravitational level was increased from low gravity (LG approximately 1.2 g) to high gravity (HG approximately 1.8 g) using a NASA KC-135 aircraft, the weld pool shape for 304 stainless steel was influenced considerably during GTAW. However, insignificant change in the microstructure and solute distribution was observed at gravitational levels between LG and HG. The GTAW on Al-4 wt% Cu alloy was used to investigate the effect of gravitational orientation on the weld solidification behavior. Gravitational orientation was manipulated by varying the welding direction with respect to gravity vector; that is, by welding upward opposing gravity ( ||-U) and downward with gravity ( ||-D) on a vertical weld piece and welding perpendicular to gravity (perpendicular) on a horizontal weld piece. Under the same welding conditions, a larger primary dendrite spacing in the ||-U weld was observed near the weld pool surface and the fusion boundary than in the case of perpendicular or ||-D welds. The ||-D weld exhibited different solidification morphology and abnormal S shape of solidification rate curve during its growth. For 304 stainless steel GTAW, significant effects of gravitational orientation were observed on the weld pool shape that was associated with weld surface morphology and convection flow. However, the weld pool shape for LBW was mostly constant with respect to the gravitational orientation.

  17. Effect of Long-Term Thermal Exposures on Microstructure and Impression Creep in 304HCu Grade Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Dash, Manmath Kumar; Karthikeyan, T.; Mythili, R.; Vijayanand, V. D.; Saroja, S.

    2017-10-01

    This paper presents the results of microstructural evolution and mechanical properties in 304H Cu grade austenite stainless (SS 304HCu) during long-term exposure at high temperatures. The predicted phase composition as a function of temperature obtained using JMatPro® software was confirmed in conjunction with the microstructural evolution characterized by scanning and transmission electron microscopy. Microstructures revealed primary Nb(C,N), M23C6 precipitates at γ-grain boundaries, fine secondary Nb(C,N) intragranular carbides, and a uniform precipitation of <40-nm-sized spherical Cu-rich phase after thermal aging for 10,000 hours at 903 K (630 °C). The impression creep rate at 300 MPa increased by a factor of 20 between 873 K and 923 K (600 °C and 650 °C). The creep rate at 903 K (630 °C) was found to moderately reduce with aging time, signifying the role of Cu-rich phase in improving the creep resistance. The deformation zones and the recrystallization behavior of the plastic zone in creep tested specimen was assessed using Electron backscatter diffraction technique.

  18. Development of a chromium-free consumable for joining stainless steels

    NASA Astrophysics Data System (ADS)

    Sowards, Jeffrey William

    Government regulations in the United States (OSHA Standards: 1910; 1915; 1917; 1918; 1926) and abroad are decreasing allowable exposure levels of hexavalent chromium to welding related personnel. The latest OSHA ruling in 2006 reduced the permissible exposure limit of airborne hexavalent chromium from 52 to 5 mug m-3. Achieving the new level may not be practical from an engineering controls standpoint during the fabrication of tightly enclosed stainless steel components such as the inside of ship hulls and boiler vessels. One method of addressing this problem is to implement a chromium-free welding consumable that provides equivalent mechanical performance and corrosion characteristics to current stainless steel welding consumables. This project was aimed at developing such a consumable and evaluating its suitability for replacement of current stainless steel consumables such as E308L-16. A new shielded metal arc welding (SMAW) consumable based on the Ni-Cu-Ru system was developed for austenitic stainless steel welding. The focus of this work was evaluating the mechanical properties, weldability, and fume formation characteristics of the various iterations of consumables developed. Welds deposited on Type 304 stainless steel were evaluated with weldability tests including: mechanical testing, hot ductility testing, Strain-to-fracture testing, Transverse Varestraint testing, and button melting. Mechanical properties of weld deposits of each consumable were found to exceed minimum values of Type 304 stainless steel based on tensile testing. Guide bend testing showed that weld deposits met minimum weld ductility requirements for stainless steel consumables, such as E308-16. Hot ductility testing revealed a narrow crack susceptible region (33 to 54°C) indicating a low susceptibility to weld metal liquation cracking. GTA welds exhibited superior ductility when compared to SMA welds. This was attributed to a lack of slag inclusions in the weld deposit, which are

  19. Fine grained 304 ASS processed by a severe plastic deformation and subsequent annealing; microstructure and mechanical properties evaluation

    NASA Astrophysics Data System (ADS)

    Salout, Shima Ahmadzadeh; Shirazi, Hasan; Nili-Ahmadabadi, Mahmoud

    2018-01-01

    The current research is an attempt to study the effect of a novel severe plastic deformation technique so called "repetitive corrugation and straightening by rolling" (RCSR) and subsequent annealing on the microstructure and mechanical properties of AISI type 304 austenitic stainless steel. In this study, RCSR process was carried out at 200 °C on the 304 austenitic stainless steel (above Md30 temperature that is about 50 °C for this stainless steel) in order to avoid the formation of martensite phase when a high density of dislocations was introduced into the austenite phase and also high density of mechanical twins was induced in the deformed 304 austenitic stainless steel. Because of relationship between deformation temperature, stacking fault energy (SFE) and mechanisms of deformation. Thereafter subsequently, annealing treatment was applied into deformed structure in order to refine the microstructure of 304 stainless s teel. The specimens were examined by means of optical microscopy (OM), scanning electron microscopy (SEM), tensile and micro-hardness tests. The results indicate that by increasing the cycles of RCSR process (increasing applied strain), further mechanical twins are induced, the hardness and in particular, the yield stress of specimens have been increased.

  20. Pitting and stress corrosion cracking of stainless steel

    NASA Astrophysics Data System (ADS)

    Saithala, Janardhan R.

    An investigation has been performed to determine the pitting resistance of stainless steels and stress corrosion cracking of super duplex stainless steels in water containing chloride ions from 25 - 170°C. The steels studied are 12% Cr, FV520B, FV566, 304L, Uranus65, 2205, Ferallium Alloy 255, and Zeron 100. All these commercial materials used in very significant industrial applications and suffer from pitting and stress corrosion failures. The design of a new experimental setup using an autoclave enabled potentiodynamic polarisation experiments and slow strain rate tests in dilute environments to be conducted at elevated temperatures. The corrosion potentials were controlled using a three electrode cell with computer controlled potentiostat.The experimental programme to determine pitting potentials was designed to simulate the service conditions experienced in most industrial plants and develop mathematical model equations to help a design engineer in material selection decision. Stress corrosion resistance of recently developed Zeron100 was evaluated in dilute environments to propose a mechanism in chloride solutions at high' temperatures useful for the nuclear and power generation industry. Results have shown the significance of the composition of alloying elements across a wide range of stainless steels and its influence on pitting. Nitrogen and molybdenum added to modern duplex stainless steels was found to be unstable at higher temperatures. The fractographic results obtained using the scanning electron microscope (SEM) has given insight in the initiation of pitting in modem duplex and super duplex stainless steels. A mathematical model has been proposed to predict pitting in stainless steels based on the effect of environmental factors (temperature, chloride concentration, and chemical composition). An attempt has been made to identify the mechanism of SCC in Zeron100 super duplex stainless steel.The proposed empirical models have shown good correlation

  1. The Influence of Hydrogen on the Evolving Microstructure During Fatigue Crack Growth in Metastable and Stable Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Nygren, Kelly Elizabeth

    The effect of high levels of internal hydrogen on the microstructure evolving during stage II fatigue crack growth was investigated through a series of tensile and fatigue studies in metastable (304) and stable (316, 316L) stainless steels. The first, a tensile study in 304 stainless steel, identified the underlying microstructure which resulted in the flat and quasi-cleavage features on the fracture surface of a hydrogen-charged tensile bar. The second study utilized single-edge notched tensile specimens loaded in fatigue, and compared the evolving microstructure ahead of a fatigue crack for cases of an uncharged, 10 wppm hydrogen-charged, and 104 wppm hydrogen-charged 304 and 316L alloy. The final fatigue study, a small fatigue crack growth study in round bars of 304 and 316, provided a contextual comparison of microstructures to previous results in literature. In the metastable 304 stainless steel, hydrogen is found to change the nature of the martensitic transformation and subsequent fracture path. This transformation is attributed to enhanced plasticity and hydrogen-dislocation interactions stabilizing the austenitic matrix and confining slip to particular close-packed planes. The martensite acts as a fast diffusion pathway for hydrogen, leading to final fracture along martensitic laths or cleavage planes. In 316L, the material deforms via slip and twinning and hydrogen does not induce a change in deformation mechanisms. Instead, the enhanced plasticity and hydrogen-dislocation interactions increase the degree of plasticity, leading to smaller dislocation cell sizes with thicker walls before the onset of twinning. The crack interacts with a heavily twinned structure superimposed on dislocation cells, resulting in a curvature of one twin-variant in the direction of crack growth and the formation of a refined region at the fracture surface. These structures are localized to the crack surface and limited in rotation in the presence of hydrogen. The presence of a

  2. Gradient twinned 304 stainless steels for high strength and high ductility

    DOE PAGES

    Chen, Aiying; Liu, Jiabin; Wang, Hongtao; ...

    2016-04-23

    Gradient materials often have attractive mechanical properties that outperform uniform microstructure counterparts. It remains a difficult task to investigate and compare the performance of various gradient microstructures due to the difficulty of fabrication, the wide range of length scales involved, and their respective volume percentage variations. We have investigated four types of gradient microstructures in 304 stainless steels that utilize submicrotwins, nanotwins, nanocrystalline-, ultrafine- and coarse-grains as building blocks. Tensile tests reveal that the gradient microstructure consisting of submicrotwins and nanotwins has a persistent and stable work hardening rate and yields an impressive combination of high strength and high ductility,more » leading to a toughness that is nearly 50% higher than that of the coarse-grained counterpart. Ex- and in-situ transmission electron microscopy indicates that nanoscale and submicroscale twins help to suppress and limit martensitic phase transformation via the confinement of martensite within the twin lamellar. Twinning and detwinning remain active during tensile deformation and contribute to the work hardening behavior. We discuss the advantageous properties of using submicrotwins as the main load carrier and nanotwins as the strengthening layers over those coarse and nanocrystalline grains. Furthermore, our work uncovers a new gradient design strategy to help metals and alloys achieve high strength and high ductility.« less

  3. Validation of a Computational Model for Autogenous Arc Welding

    DTIC Science & Technology

    1990-03-01

    Structure of Austenitic Stainless Steels ." M1etallurgical 7Tansactions A, v.20A, May 1989. Zacharia. T., Eraslan. A.l.. and Aidun. D.K., "Modeling of...Figure 4. Temperature profiles for low and high conductivity flaws ........... 13 Figure 5. Rosenthal verification results...The sulfur contents (90 ppm and 24() ppn’n had a significant effect on the weld penetration for the GTA process for 304 stainless steel , however, there

  4. Thermal desorption of CO and H2 from degassed 304 and 347 stainless steel

    NASA Technical Reports Server (NTRS)

    Rezaie-Serej, S.; Outlaw, R. A.

    1994-01-01

    Thermal desorption spectroscopy (TDS), along with Auger electron spectroscopy, was used to study the desorption of H2 and CO from baked 304 and 347 stainless-steel samples exposed only to residual gases. Both 347 and 304 samples gave identical TDS spectra. The spectra for CO contained a sharp leading peak centered in the temperature range 410-440C and an exponentially increasing part for temperatures higher than 500C, with a small peak around 600C appearing as a shoulder. The leading peak followed a second-order desorption behavior with an activation energy of 28+/-2 kcal/mol, suggesting that the rate-limiting step for this peak is most likely a surface reaction that produces the CO molecules in the surface layer. The amount of desorbed CO corresponding to this peak was approximately 0.5X10(exp 14) molecules/cm(exp 2) . The exponentially rising part of the CO spectrum appeared to originate from a bulk diffusion process. The TDS spectrum for H2 consisted of a main peak centered also in the temperature range 410-440C, with two small peaks appearing as shoulders at approximately 500 and 650C. The main peak in this case also displayed a second-order behavior with an activation energy of 14+/-2 kcal/mol. The amount of desorbed H2, approximately 1.9X 10(exp 15) molecules/cm(exp 2) , appeared to be independent of the concentration of hydrogen in the bulk, indicating that the majority of the desorbed H2 originated from the surface layer.

  5. Effect of Inhibitor Agents Addition on Corrosion Resistance Performance of Titania Sol-Gel Coatings Applied on 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Shanaghi, Ali; Chu, Paul K.; Moradi, Hadi

    Hybrid organic-inorganic coatings are deposited on 304 stainless steel substrates by the sol-gel technique to improve the corrosion resistance. A titania-based nanostructured hybrid sol-gel coating is impregnated with three different microencapsulated healing agents (inhibitors) including cerium, Benzotriazole (BTA), and 8-Hydroxyquinoline (8H). Field-emission scanning electron microscopy (FE-SEM) and electrochemical impedance spectroscopy (EIS) are performed to investigate the barrier performance properties. The optimum conditions to achieve corrosion protective coatings for 304 stainless steel were determined. The Nyquist plots demonstrate that the activation time of the coating containing 8H as an organic healing agent shows improved behavior when compared to other coatings including cerium and BTA. Cerium as an inorganic healing agent is second and BTA is third and minimum. An increase in the impedance parameters such as resistance and capacitance as a function of immersion time is achieved in a 3.5wt.% NaCl solution by using healing agents such as BTA. Actually, over the course of immersion, the barrier performance behavior of the coatings changes and reduction of the impedance observed from the coatings containing Ce and 8H discloses deterioration of the protection system after immersion for 96h of immersion in the 3.5% NaCl solution. However, after 96h of immersion time, the concentration of chloride ions is high and causes increase in defects, micro cracks, hole on the surface of hybrid titania nanostructured coating containing Ce and 8H by destruction of coating, and also hybrid titania nanostructured coating containing BTA; BTA is released from coating to improve the resistance of passive film, which is created on the surface.

  6. Ultrasonic Corrosion Fatigue Behavior of High Strength Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Ebara, R.; Yamaguchi, Y.; Kanei, D.; Yamamoto, Y.

    Ultrasonic corrosion fatigue tests were conducted for high strength austenitic stainless steels such as YUS270 and SUS304N2 in 3%NaCl aqueous solution. The reduction of giga-cycle corrosion fatigue strength of YUS270 and SUS304N2 was not observed at all, while the reduction of corrosion fatigue life was observed at higher stress amplitude. Corrosion pit was observed on corrosion fatigue crack initiation area. Striation was predominantly observed on crack propagation area in air and in 3% NaCl aqueous solution. The reduction of corrosion fatigue strength of high strength austenitic stainless steels such as YUS270 and SUS304N2 is due to the corrosion pit formation at corrosion fatigue crack initiation area. It can be concluded that the higher the ultimate tensile strength of austenitic stainless steels the higher the giga-cycle corrosion fatigue strength in 3%NaCl aqueous solution is.

  7. Biomaterial Studies on AISI 316L Stainless Steel after Magnetoelectropolishing

    PubMed Central

    Hryniewicz, Tadeusz; Rokosz, Krzysztof; Filippi, Massimiliano

    2009-01-01

    The polarisation characteristics of the electropolishing process in a magnetic field (MEP – magnetoelectropolishing), in comparison with those obtained under standard/conventional process (EP) conditions, have been obtained. The occurrence of an EP plateau has been observed in view of the optimization of MEP process. Up-to-date stainless steel surface studies always indicated some amount of free-metal atoms apart from the detected oxides and hydroxides. Such a morphology of the surface film usually affects the thermodynamic stability and corrosion resistance of surface oxide layer and is one of the most important features of stainless steels. With this new MEP process we can improve metal surface properties by making the stainless steel more resistant to halides encountered in a variety of environments. Furthermore, in this paper the stainless steel surface film study results have been presented. The results of the corrosion research carried out by the authors on the behaviour of the most commonly used material − medical grade AISI 316L stainless steel both in Ringer’s body fluid and in aqueous 3% NaCl solution have been investigated and presented earlier elsewhere, though some of these results, concerning the EIS Nyquist plots and polarization curves are also revealed herein. In this paper an attempt to explain this peculiar performance of 316L stainless steel has been undertaken. The SEM studies, Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) were performed on 316L samples after three treatments: MP – abrasive polishing (800 grit size), EP – conventional electrolytic polishing, and MEP – magnetoelectropolishing. It has been found that the proposed magnetoelectropolishing (MEP) process considerably modifies the morphology and the composition of the surface film, thus leading to improved corrosion resistance of the studied 316L SS.

  8. Sliding Wear Characteristics and Corrosion Behaviour of Selective Laser Melted 316L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Sun, Y.; Moroz, A.; Alrbaey, K.

    2014-02-01

    Stainless steel is one of the most popular materials used for selective laser melting (SLM) processing to produce nearly fully dense components from 3D CAD models. The tribological and corrosion properties of stainless steel components are important in many engineering applications. In this work, the wear behaviour of SLM 316L stainless steel was investigated under dry sliding conditions, and the corrosion properties were measured electrochemically in a chloride containing solution. The results show that as compared to the standard bulk 316L steel, the SLM 316L steel exhibits deteriorated dry sliding wear resistance. The wear rate of SLM steel is dependent on the vol.% porosity in the steel and by obtaining full density it is possible achieve wear resistance similar to that of the standard bulk 316L steel. In the tested chloride containing solution, the general corrosion behaviour of the SLM steel is similar to that of the standard bulk 316L steel, but the SLM steel suffers from a reduced breakdown potential and is more susceptible to pitting corrosion. Efforts have been made to correlate the obtained results with porosity in the SLM steel.

  9. Vacuum Brazing TC4 Titanium Alloy to 304 Stainless Steel with Cu-Ti-Ni-Zr-V Amorphous Alloy Foil

    NASA Astrophysics Data System (ADS)

    Dong, Honggang; Yang, Zhonglin; Wang, Zengrui; Deng, Dewei; Dong, Chuang

    2014-10-01

    Dissimilar metal vacuum brazing between TC4 titanium alloy and 304 stainless steel was conducted with newly designed Cu-Ti-Ni-Zr-V amorphous alloy foils as filler metals. Solid joints were obtained due to excellent compatibility between the filler metal and stainless steel substrate. Partial dissolution of stainless steel substrate occurred during brazing. The shear strength of the joint brazed with Cu43.75Ti37.5Ni6.25Zr6.25V6.25 foil was 105 MPa and that with Cu37.5Ti25Ni12.5Zr12.5V12.5 was 116 MPa. All the joints fractured through the gray layer in the brazed seam, revealing brittle fracture features. Cr4Ti, Cu0.8FeTi, Fe8TiZr3 and Al2NiTi3C compounds were found in the fractured joint brazed with Cu43.75Ti37.5Ni6.25Zr6.25V6.25 foil, and Fe2Ti, TiCu, Fe8TiZr3 and NiTi0.8Zr0.3 compounds were detected in the joint brazed with Cu37.5Ti25Ni12.5Zr12.5V12.5 foil. The existence of Cr-Ti, Fe-Ti, Cu-Fe-Ti, and Fe-Ti-V intermetallic compounds in the brazed seam caused fracture of the resultant joints.

  10. Microstructure and Low-Temperature Mechanical Properties of 304 Stainless Steel Joints by PAW + GTAW Combined Welding

    NASA Astrophysics Data System (ADS)

    Liu, Kun; Li, Yajiang; Wang, Juan

    2016-10-01

    The combined double-pass process of plasma arc welding (PAW) + gas tungsten arc welding (GTAW) was performed on 304 austenitic stainless steel with the thickness of 12 mm. Results indicated that two different morphologies of ferrite (e.g., lathy δ-ferrite and skeletal δ-ferrite) were formed within the austenite matrix in PAW weld metal (PAW-WM). GTAW weld metal (GTAW-WM) was mainly composed of fine austenite and skeletal δ-ferrite. In transition zone between PAW-WM and GTAW-WM, epitaxial growth contributed to cellular dendritic crystals transforming into columnar crystals. The tensile strength of joint is about 700 MPa. The impact toughness of WM varied from 281 J (20 °C) to 122 (-196 °C), while the impact toughness of heat-affected zone (HAZ) varied from 205 J (20 °C) to 112 J (-196 °C).

  11. Study on Microstructure and Mechanical Properties of 304 Stainless Steel Joints by Tig-Mig Hybrid Welding

    NASA Astrophysics Data System (ADS)

    Ogundimu, Emmanuel O.; Akinlabi, Esther T.; Erinosho, Mutiu F.

    Stainless steel is a family of Fe-based alloys having excellent resistance to corrosion and as such has been used imperatively for kitchen utensils, transportation, building constructions and much more. This paper presents the work conducted on the material characterizations of a tungsten inert gas (TIG)-metal inert gas (MIG) hybrid welded joint of type 304 austenitic stainless steel. The welding processes were conducted in three phases. The phases of welding employed are MIG welding using a current of 170A, TIG welding using a current of 190A, and a hybrid TIG-MIG welding with currents of 190/170A, respectively. The MIG, TIG, and hybrid TIG-MIG weldments were characterized with incomplete penetration, full penetration and excess penetration of weld. Intergranular austenite was created toward transition and heat affected zones. The thickness of the delta ferrite (δ-Fe) formed in the microstructures of the TIG weld is more than the thickness emerged in the microstructures of MIG and hybrid TIG-MIG welds. A TIG-MIG hybrid weld of specimen welded at the currents of 190/170A has the highest ultimate tensile strength value and percentage elongation of 397.72MPa and 35.7%. The TIG-MIG hybrid welding can be recommended for high-tech industrial applications such as nuclear, aircraft, food processing, and automobile industry.

  12. Microstructure and corrosion resistance of nitrogen-rich surface layers on AISI 304 stainless steel by rapid nitriding in a hollow cathode discharge

    NASA Astrophysics Data System (ADS)

    Li, Yang; He, Yongyong; Zhang, Shangzhou; Wang, Wei; Zhu, Yijie

    2018-01-01

    Nitriding treatments have been successfully applied to austenitic stainless steels to improve their hardness and tribological properties. However, at temperatures above 450 °C, conventional plasma nitriding processes decrease the corrosion resistance due to the formation of CrN phases within the modified layer. In this work, AISI 304 austenitic stainless steels were efficiently treated by rapid plasma nitriding at a high temperature of 530 °C in a hollow cathode discharge. The enhanced ionization obtained in the hollow cathode configuration provided a high current density and, consequently, a high temperature could be attained in a short time. The nitrided layers were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The results indicated that the dual-layer structure of the nitrided layer consists of a high-N face-centered cubic structure with a free CrN precipitate outer (top) layer and a nitrogen-expanded austenite S-phase bottom layer. The rapid nitriding-assisted hollow cathode discharge technique permits the use of high temperatures, as high as 530 °C, without promoting degradation in the corrosion resistance of stainless steel.

  13. Evolution of Microstructure and Residual Stress under Various Vibration Modes in 304 Stainless Steel Welds

    PubMed Central

    Wang, Peng-Shuen; Wang, Jia-Siang

    2014-01-01

    Simultaneous vibration welding of 304 stainless steel was carried out with an eccentric circulating vibrator and a magnetic telescopic vibrator at subresonant (362 Hz and 59.3 Hz) and resonant (376 Hz and 60.9 Hz) frequencies. The experimental results indicate that the temperature gradient can be increased, accelerating nucleation and causing grain refinement during this process. During simultaneous vibration welding primary δ-ferrite can be refined and the morphologies of retained δ-ferrite become discontinuous so that δ-ferrite contents decrease. The smallest content of δ-ferrite (5.5%) occurred using the eccentric circulating vibrator. The diffraction intensities decreased and the FWHM widened with both vibration and no vibration. A residual stress can obviously be increased, producing an excellent effect on stress relief at a resonant frequency. The stress relief effect with an eccentric circulating vibrator was better than that obtained using a magnetic telescopic vibrator. PMID:24605068

  14. Comparison of the Electrochemical Behavior of Ti and Nanostructured Ti-Coated AISI 304 Stainless Steel in Strongly Acidic Solutions

    NASA Astrophysics Data System (ADS)

    Attarzadeh, Farid Reza; Elmkhah, Hassan; Fattah-Alhosseini, Arash

    2017-02-01

    In this study, the electrochemical behaviors of pure titanium (Ti) and nanostructured (NS) Ti-coated AISI 304 stainless steel (SS) in strongly acidic solutions of H2SO4 were investigated and compared. A type of physical vapor deposition method, cathodic arc evaporation, was applied to deposit NS Ti on 304 SS. Scanning electron microscope and X-ray diffraction were used to characterize surface coating morphology. Potentiodynamic polarization, electrochemical impedance spectroscopy, and Mott-Schottky (M-S) analysis were used to evaluate the passive behavior of the samples. Electrochemical measurements revealed that the passive behavior of NS Ti coating was better than that of pure Ti in 0.1 and 0.01 M H2SO4 solutions. M-S analysis indicated that the passive films behaved as n-type semiconductors in H2SO4 solutions and the deposition method did not affect the semiconducting type of passive films formed on the coated samples. In addition, this analysis showed that the NS Ti coating had lower donor densities. Finally, all electrochemical tests showed that the passive behavior of the Ti-coated samples was superior, mainly due to the formation of thicker, yet less defective passive films.

  15. Effect of proof testing on the flaw growth characteristics of 304 stainless steel. [crack propagation in welded joints

    NASA Technical Reports Server (NTRS)

    Finger, R. W.

    1974-01-01

    The effects of proof overload frequency and magnitude on the cyclic crack growth rates of 304 stainless steel weldments were investigated. The welding procedure employed was typical of those used on over-the-road cryogenic vessels. Tests were conducted at room temperature with an overload ratio of 1.50 to determine the effect of overload frequency. Effect of overload magnitude was determined from tests where a room temperature overload was applied between blocks of 1000 cycles applied at 78 K (-320 F). The cyclic stress level used in all tests was typical of the nominal membrane stress generally encountered in full scale vessels. Test results indicate that judicious selection of proof overload frequency and magnitude can reduce crack growth rates for cyclic stress levels.

  16. Defining the Post-Machined Sub-surface in Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Srinivasan, N.; Sunil Kumar, B.; Kain, V.; Birbilis, N.; Joshi, S. S.; Sivaprasad, P. V.; Chai, G.; Durgaprasad, A.; Bhattacharya, S.; Samajdar, I.

    2018-04-01

    Austenitic stainless steels grades, with differences in chemistry, stacking fault energy, and thermal conductivity, were subjected to vertical milling. Anodic potentiodynamic polarization was able to differentiate (with machining speed/strain rate) between different post-machined sub-surfaces in SS 316L and Alloy A (a Cu containing austenitic stainless steel: Sanicroe 28™), but not in SS 304L. However, such differences (in the post-machined sub-surfaces) were revealed in surface roughness, sub-surface residual stresses and misorientations, and in the relative presence of sub-surface Cr2O3 films. It was shown, quantitatively, that higher machining speed reduced surface roughness and also reduced the effective depths of the affected sub-surface layers. A qualitative explanation on the sub-surface microstructural developments was provided based on the temperature-dependent thermal conductivity values. The results herein represent a mechanistic understanding to rationalize the corrosion performance of widely adopted engineering alloys.

  17. Defining the Post-Machined Sub-surface in Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Srinivasan, N.; Sunil Kumar, B.; Kain, V.; Birbilis, N.; Joshi, S. S.; Sivaprasad, P. V.; Chai, G.; Durgaprasad, A.; Bhattacharya, S.; Samajdar, I.

    2018-06-01

    Austenitic stainless steels grades, with differences in chemistry, stacking fault energy, and thermal conductivity, were subjected to vertical milling. Anodic potentiodynamic polarization was able to differentiate (with machining speed/strain rate) between different post-machined sub-surfaces in SS 316L and Alloy A (a Cu containing austenitic stainless steel: Sanicroe 28™), but not in SS 304L. However, such differences (in the post-machined sub-surfaces) were revealed in surface roughness, sub-surface residual stresses and misorientations, and in the relative presence of sub-surface Cr2O3 films. It was shown, quantitatively, that higher machining speed reduced surface roughness and also reduced the effective depths of the affected sub-surface layers. A qualitative explanation on the sub-surface microstructural developments was provided based on the temperature-dependent thermal conductivity values. The results herein represent a mechanistic understanding to rationalize the corrosion performance of widely adopted engineering alloys.

  18. 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.

  19. The determination of micro-arc plasma composition and properties of nanoparticles formed during cathodic plasma electrolysis of 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Jovović, Jovica; Stojadinović, Stevan; Vasilić, Rastko; Tadić, Nenad; Šišović, Nikola M.

    2017-05-01

    This paper presents the research focused on the determination of micro-arc plasma composition during cathodic plasma electrolysis of AISI304 stainless steel in water solution of sodium hydroxide. The complex line shape of several Fe I spectral lines was observed and, by means of a dedicated fitting procedure based on the spectral line broadening theory and H2O thermal decomposition data, the mole fraction of micro-arc plasma constituents (H2, Fe, O, H, H2O, and OH) was determined. Subsequent characterization of the cathodic plasma electrolysis product formed during the process revealed that it consists of Fe-nanoparticles with median diameter of approximately 60 nm.

  20. Effect of vibration on microstructures and mechanical properties of 304 stainless steel GTA welds

    NASA Astrophysics Data System (ADS)

    Hsieh, Chih-Chun; Lai, Chien-Hong; Wu, Weite

    2013-07-01

    This study investigates the microstructures and mechanical properties of 304 stainless steel at various vibration frequencies during simultaneous vibration welding. The experimental results demonstrated that simultaneous vibration welding could accelerate the nucleation and grain refinement of the microstructures. The effect of the grain refinement was more evident at the resonant frequency (375 Hz) and a minimum content of residual δ-ferrite (4.0%). The γ phase grew in the preferential orientation of the (111) direction with and without vibration. The full width at half maximum of the diffraction peak widened after the vibration, which was attributed to the grain refinement. The residual stress could be efficiently removed through simultaneous vibration welding when the amplitude of the vibration was increased. Furthermore, the lowest residual stress (139 MPa) was found when the vibration frequency was 375 Hz. The hardness and Young's modulus exhibited slight increases with low and medium frequencies. The hardness values were increased by 7.6% and Young's modulus was increased by 15% when the vibration frequency was resonant (375 Hz).

  1. Effect of Cryogenic Treatment on Sensitization of 304 Stainless Steel in TIG Welding

    NASA Astrophysics Data System (ADS)

    Singh, Rupinder; Slathia, Ravinder Singh

    2016-04-01

    Stainless steel (SS) is sensitized by a thermal treatment in the range of 400-850 °C and inter-granular attack would occur upon subsequent exposure to certain media. In many practical situations, such as welding, sensitization is best studied by continuous cooling through the sensitizing temperature range wherein the variables are the peak temperature reached and the cooling rate in contrast to temperature and time of the isothermal hold which has been the customary practice. There are also various methods of controlling the inter-granular corrosion viz. lowering the carbon content, adding stabilizers and applying solution heat treatment but all these methods are either costly or difficult to apply. This study is focussed on the effect of cryogenically treated tungsten electrode of TIG welding on the sensitization behaviour of 304SS by taking into consideration the weld properties (like: hardness, tensile strength, percentage elongation and micro-structure). The parameters of significance are current, pulse frequency and gas flow rate. Further the study suggested that the results of non cryo treated electrode were better than the treated one on sensitization of welded joints during TIG welding within the range of selected parameters.

  2. Low-temperature creep of austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Reed, R. P.; Walsh, R. P.

    2017-09-01

    Plastic deformation under constant load (creep) in austenitic stainless steels has been measured at temperatures ranging from 4 K to room temperature. Low-temperature creep data taken from past and unreported austenitic stainless steel studies are analyzed and reviewed. Creep at cryogenic temperatures of common austenitic steels, such as AISI 304, 310 316, and nitrogen-strengthened steels, such as 304HN and 3116LN, are included. Analyses suggests that logarithmic creep (creep strain dependent on the log of test time) best describe austenitic stainless steel behavior in the secondary creep stage and that the slope of creep strain versus log time is dependent on the applied stress/yield strength ratio. The role of cold work, strain-induced martensitic transformations, and stacking fault energy on low-temperature creep behavior is discussed. The engineering significance of creep on cryogenic structures is discussed in terms of the total creep strain under constant load over their operational lifetime at allowable stress levels.

  3. Cryogenic thermal emittance measurements on small-diameter stainless steel tubing

    NASA Astrophysics Data System (ADS)

    Jahromi, Amir E.; Tuttle, James G.; Canavan, Edgar R.

    2017-12-01

    The Mid Infrared Instrument aboard the James Webb Space Telescope includes a mechanical cryocooler which cools its detectors to their 6 K operating temperature. The refrigerant flows through several meters of ~2 mm diameter 304L stainless steel tubing, with some sections gold plated, and some not, which are exposed to their environment. An issue of water freezing onto the tube surfaces is mitigated by running a warm gas through the lines to sublimate the frozen water. To model the effect of this process on nearby instruments, an accurate measure of the tube emittance is needed. Previously we reported the absorptance of the gold plated stainless steel tubing as a function of source temperature (i.e. its environment). In this work the thermal emittance of the uncoated tubing is measured as a function of its temperature between 100 and 280 K. These values lead to an accurate prediction of the minimum length of time required to thermally recycle the system. We report the technique and present the results.

  4. Cryogenic Thermal Emittance Measurements on Small-Diameter Stainless Steel Tubing

    NASA Technical Reports Server (NTRS)

    Jahromi, Amir E.; Tuttle, James G.; Canavan, Edgar R.

    2017-01-01

    The Mid Infrared Instrument aboard the James Webb Space Telescope includes a mechanical cryocooler which cools its detectors to their 6 K operating temperature. The refrigerant flows through several meters of 2 mm diameter 304L stainless steel tubing, with some sections gold plated, and some not, which are exposed to their environment. An issue of water freezing onto the tube surfaces is mitigated by running a warm gas through the lines to sublimate the frozen water. To model the effect of this process on nearby instruments, an accurate measure of the tube emittance is needed. Previously we reported the absorptance of the gold plated stainless steel tubing as a function of source temperature (i.e. its environment). In this work the thermal emittance of the uncoated tubing is measured as a function of its temperature between 100 and 280 K. These values lead to an accurate prediction of the minimum length of time required to thermally recycle the system. We report the technique and present the results.

  5. Cryogenic Thermal Emittance Measurements on Small-Diameter Stainless Steel Tubing

    NASA Technical Reports Server (NTRS)

    Jahromi, A. E.; Tuttle, J. G.; Canavan, E. R.

    2017-01-01

    The Mid Infrared Instrument aboard the James Webb Space Telescoep includes a mechanical cryocooler which cools its detectors to their 6 K operating temperature. The refrigerant flows through several meters of approximately 2 mm diameter 304L stainless steel tubing, with some sections gold plated, and some not, which are exposed to their environment. An issue of water freezing onto the tube surfaces is mitigated by a running a warm gas through the lines to sublimate the water. To model the effect of this process on nearby instruments, an accurate measure of the tube emittance is needed. Previously we reported the abosprtance of the gold plated stainless steel tubing as a function of source temperature (i.e. its environment). In this work the thermal emittance of the uncoated tubing is measured as a function of its temperature between 100 and 300 K. This value leads to an accurate prediction of the minimum length of time required to thermally recycle the system. We report the technique and present the results.

  6. On the modified grain-size-distribution method to evaluate the dynamic recrystallisation fraction in AISI 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Hong, D. H.; Park, J. K.

    2018-04-01

    The purpose of the present work was to verify the grain size distribution (GSD) method, which was recently proposed by one of the present authors as a method for evaluating the fraction of dynamic recrystallisation (DRX) in a microalloyed medium carbon steel. To verify the GSD-method, we have selected a 304 stainless steel as a model system and have measured the evolution of the overall grain size distribution (including both the recrystallised and unrecrystallised grains) during hot compression at 1,000 °C in a Gleeble machine; the DRX fraction estimated using the GSD method is compared with the experimentally measured value via EBSD. The results show that the previous GSD method tends to overestimate the DRX fraction due to the utilisation of a plain lognormal distribution function (LDF). To overcome this shortcoming, we propose a modified GSD-method wherein an area-weighted LDF, in place of a plain LDF, is employed to model the evolution of GSD during hot deformation. Direct measurement of the DRX fraction using EBSD confirms that the modified GSD-method provides a reliable method for evaluating the DRX fraction from the experimentally measured GSDs. Reasonable agreement between the DRX fraction and softening fraction suggests that the Kocks-Mecking method utilising the Voce equation can be satisfactorily used to model the work hardening and dynamic recovery behaviour of steels during hot deformation.

  7. Identification of the mechanism that confers superhydrophobicity on 316L stainless steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Escobar, Ana M.; Llorca-Isern, Nuria; Rius-Ayra, Oriol

    This study develops a rapid method to confer superhydrophobicity on 316L stainless steel surfaces with an amphiphilic reagent such as dodecanoic acid. The highest contact angle (approaching 173°) was obtained after forming hierarchical structures with a non-aqueous electrolyte by an electrolytic process. Our goal was to induce superhydrophobicity directly on 316L stainless steel substrates and to establish which molecules cause the effect. The superhydrophobic behaviour is analysed by contact angle measurements, scanning electron microscopy (SEM), IR spectroscopy and atomic force microscopy (AFM). The growth mechanism is analysed using FE-SEM, TOF-SIMS and XPS in order to determine the molecules involved inmore » the reaction and the growth. The TOF-SIMS analysis revealed that the Ni{sup 2+} ions react with lauric acid to create an ester on the stainless steel surface. - Highlights: • This study develops a rapid and facile approach to impart superhydrophobicity properties to 316L stainless steel surfaces with an amphiphilic reagent such as dodecanoic acid. Surface character changes from superhydrophilicity to superhydrophobicity. • This process changes the surface character from superhydrophilicity to superhydrophobicity. • The process based on electrolysis of a nickel salt in lauric acid provides superhydrophobic behaviour in 316L stainless steel. • The growth mechanism is proposed as a mode island (Volmert- Weber mode). • TOF-SIMS and XPS provided the identification of the molecules involved in the surface modification reaction on AISI 316L inducing superhydrophobicity.« less

  8. 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.

  9. Fracture and crack growth resistance studies of 304 stainless steel weldments relating to retesting of cryogenic vessels

    NASA Technical Reports Server (NTRS)

    Hall, L. R.; Finger, R. W.

    1972-01-01

    Fracture and crack growth resistance characteristics of 304 stainless steel alloy weldments as relating to retesting of cryogenic vessels were examined. Welding procedures were typical of those used in full scale vessel fabrication. Fracture resistance survey tests were conducted in room temperature air, liquid nitrogen and liquid hydrogen. In air, both surface-flawed and center-cracked panels containing cracks in weld metal, fusion line, heat-affected zone, or parent metal were tested. In liquid nitrogen and liquid hydrogen, tests were conducted using center-cracked panels containing weld centerline cracks. Load-unload, sustained load, and cyclic load tests were performed in air or hydrogen gas, liquid nitrogen, and liquid hydrogen using surface-flawed specimens containing weld centerline cracks. Results were used to evaluate the effectiveness of periodic proof overloads in assuring safe and reliable operation of over-the-road cryogenic dewars.

  10. Laser-assisted electrochemical micromachining of mould cavity on the stainless steel surface

    NASA Astrophysics Data System (ADS)

    Li, Xiaohai; Wang, Shuming; Wang, Dong; Tong, Han

    2018-02-01

    In order to fabricate the micro mould cavities with complex structures on 304 stainless steel, laser-assisted electrochemical micromachining (EMM) based on surface modification by fiber laser masking was studied,and a new device of laser-assisted EMM was developed. Laser marking on the surface of 304 stainless steel can first be realized by fiber laser heating scanning. Through analysis of X ray diffraction analysis (XRD), metal oxide layer with predefined pattern can be formed by laser marking, and phase transformation can also occur on the 304 stainless steel surface, which produce the laser masking layer with corrosion resistance. The stainless steel surface with laser masking layer is subsequently etched by EMM, the laser masking layer severs as the temporary protective layer without relying on lithography mask, the fabrication of formed electrodes is also avoided, so micro pattern cavities can fast be fabricated. The impacts on machining accuracy during EMM with laser masking were discussed to optimize machining parameters, such as machining voltage, electrolyte concentration, duty cycle of pulse power supply and electrode gap size, the typical mould cavities 23μm deep were fabricated under the optimized parameters.

  11. 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.

  12. Spatially resolved texture and microstructure evolution of additively manufactured and gas gun deformed 304L stainless steel investigated by neutron diffraction and electron backscatter diffraction

    DOE PAGES

    Takajo, Shigehiro; Brown, Donald William; Clausen, Bjorn; ...

    2018-04-30

    In this study, we report the characterization of a 304L stainless steel cylindrical projectile produced by additive manufacturing. The projectile was compressively deformed using a Taylor Anvil Gas Gun, leading to a huge strain gradient along the axis of the deformed cylinder. Spatially resolved neutron diffraction measurements on the HIgh Pressure Preferred Orientation time-of-flight diffractometer (HIPPO) and Spectrometer for Materials Research at Temperature and Stress diffractometer (SMARTS) beamlines at the Los Alamos Neutron Science CEnter (LANSCE) with Rietveld and single-peak analysis were used to quantitatively evaluate the volume fractions of the α, γ, and ε phases as well as residualmore » strain and texture. The texture of the γ phase is consistent with uniaxial compression, while the α texture can be explained by the Kurdjumov–Sachs relationship from the γ texture after deformation. This indicates that the material first deformed in the γ phase and subsequently transformed at larger strains. The ε phase was only found in volumes close to the undeformed material with a texture connected to the γ texture by the Shoji–Nishiyama orientation relationship. This allows us to conclude that the ε phase occurs as an intermediate phase at lower strain, and is superseded by the α phase when strain increases further. We found a proportionality between the root-mean-squared microstrain of the γ phase, dominated by the dislocation density, with the α volume fraction, consistent with strain-induced martensite α formation. In conclusion, knowledge of the sample volume with the ε phase from the neutron diffraction analysis allowed us to identify the ε phase by electron back scatter diffraction analysis, complementing the neutron diffraction analysis with characterization on the grain level.« less

  13. Spatially resolved texture and microstructure evolution of additively manufactured and gas gun deformed 304L stainless steel investigated by neutron diffraction and electron backscatter diffraction

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Takajo, Shigehiro; Brown, Donald William; Clausen, Bjorn

    In this study, we report the characterization of a 304L stainless steel cylindrical projectile produced by additive manufacturing. The projectile was compressively deformed using a Taylor Anvil Gas Gun, leading to a huge strain gradient along the axis of the deformed cylinder. Spatially resolved neutron diffraction measurements on the HIgh Pressure Preferred Orientation time-of-flight diffractometer (HIPPO) and Spectrometer for Materials Research at Temperature and Stress diffractometer (SMARTS) beamlines at the Los Alamos Neutron Science CEnter (LANSCE) with Rietveld and single-peak analysis were used to quantitatively evaluate the volume fractions of the α, γ, and ε phases as well as residualmore » strain and texture. The texture of the γ phase is consistent with uniaxial compression, while the α texture can be explained by the Kurdjumov–Sachs relationship from the γ texture after deformation. This indicates that the material first deformed in the γ phase and subsequently transformed at larger strains. The ε phase was only found in volumes close to the undeformed material with a texture connected to the γ texture by the Shoji–Nishiyama orientation relationship. This allows us to conclude that the ε phase occurs as an intermediate phase at lower strain, and is superseded by the α phase when strain increases further. We found a proportionality between the root-mean-squared microstrain of the γ phase, dominated by the dislocation density, with the α volume fraction, consistent with strain-induced martensite α formation. In conclusion, knowledge of the sample volume with the ε phase from the neutron diffraction analysis allowed us to identify the ε phase by electron back scatter diffraction analysis, complementing the neutron diffraction analysis with characterization on the grain level.« less

  14. Experimental Study and Fractal Analysis on the Anisotropic Performance of Explosively Welded Interfaces of 304 Stainless Steel/245 Carbon Steel

    NASA Astrophysics Data System (ADS)

    Fu, Yanshu; Qiu, Yaohui; Li, Yulong

    2018-03-01

    The mechanical anisotropy of an explosive welding composite plate made of 304 stainless steel/245 steel was studied through shear experiments performed on explosively welded wavy interfaces along several orientation angles. The results indicated that the strength and the fracture energy of samples significantly varied with the orientation angles. The fracture surfaces of all samples were observed using a scanning electron microscope and through three-dimensional structure microscopy. The periodic features of all the fracture surfaces were clearly shown in different fracture modes. The fractal dimension of the fracture surfaces was calculated based on the fractal geometry by the box-counting method in MATLAB. The cohesive element model was used to analyze the fracture energy according to the physical dependence of the fractal dimension on thermodynamic entropy and interface separation energy. The fracture energy was an exponential function of the fractal dimension value, which was in good agreement with the experimental results. All results were validated for effective use in the application of anisotropy analysis to the welded interface and structural optimization of explosively welded composite plates.

  15. Experimental Study and Fractal Analysis on the Anisotropic Performance of Explosively Welded Interfaces of 304 Stainless Steel/245 Carbon Steel

    NASA Astrophysics Data System (ADS)

    Fu, Yanshu; Qiu, Yaohui; Li, Yulong

    2018-05-01

    The mechanical anisotropy of an explosive welding composite plate made of 304 stainless steel/245 steel was studied through shear experiments performed on explosively welded wavy interfaces along several orientation angles. The results indicated that the strength and the fracture energy of samples significantly varied with the orientation angles. The fracture surfaces of all samples were observed using a scanning electron microscope and through three-dimensional structure microscopy. The periodic features of all the fracture surfaces were clearly shown in different fracture modes. The fractal dimension of the fracture surfaces was calculated based on the fractal geometry by the box-counting method in MATLAB. The cohesive element model was used to analyze the fracture energy according to the physical dependence of the fractal dimension on thermodynamic entropy and interface separation energy. The fracture energy was an exponential function of the fractal dimension value, which was in good agreement with the experimental results. All results were validated for effective use in the application of anisotropy analysis to the welded interface and structural optimization of explosively welded composite plates.

  16. Laser micropolishing of AISI 304 stainless steel surfaces for cleanability and bacteria removal capability

    NASA Astrophysics Data System (ADS)

    De Giorgi, Chiara; Furlan, Valentina; Demir, Ali Gökhan; Tallarita, Elena; Candiani, Gabriele; Previtali, Barbara

    2017-06-01

    In this work, laser micropolishing (LμP) was employed to reduce the surface roughness and waviness of cold-rolled AISI 304 stainless steel sheets. A pulsed fibre laser operating in the ns regime was used and the influence of laser parameters in a N2-controlled atmospheres was evaluated. In the optimal conditions, the surface remelting induced by the process allowed to reduce the surface roughness by closing cracks and defects formed during the rolling process. Other conditions that did not improve the surface quality were analysed for defect typology. Moreover, laser treatments allowed the production of more hydrophobic surfaces, and no surface chemistry modification was identified. Surface cleanability was investigated with Escherichia coli (E. coli), evaluating the number of residual bacteria adhering to the substrate after a washing procedure. These results showed that LμP is a suitable way to lower the average surface roughness by about 58% and average surface waviness by approximately 38%. The LμP process proved to be effective on the bacteria cleanability as approximately five times fewer bacteria remained on the surfaces treated with the optimized LμP parameters compared to the untreated surfaces.

  17. Micro-Abrasion Wear Resistance of Borided 316L Stainless Steel and AISI 1018 Steel

    NASA Astrophysics Data System (ADS)

    Reséndiz-Calderon, C. D.; Rodríguez-Castro, G. A.; Meneses-Amador, A.; Campos-Silva, I. E.; Andraca-Adame, J.; Palomar-Pardavé, M. E.; Gallardo-Hernández, E. A.

    2017-11-01

    The 316L stainless steel has high corrosion resistance but low tribological performance. In different industrial sectors (biomedical, chemical, petrochemical, and nuclear engineering), improvement upon wear resistance of 316L stainless steel components using accessible and inexpensive methods is critical. The AISI 1018 steel is widely used in industry, but its tribological performance is not the best among steels. Therefore, in this study the behavior of the borided 316L stainless steel and 1018 steel is evaluated under micro-abrasion wear. The boriding was carried out at 1223 K over 6 h of exposure time, resulting in a biphase layer composed of FeB/Fe2B phases. In order to evaluate Fe2B phase with no influence from FeB phase, AISI 1018 steel samples were borided at 1273 K for over 20 min and then diffusion annealed at 1273 K over 2 h to obtain a Fe2B mono-phase layer. Micro-abrasion wear resistance was evaluated by a commercial micro-abrasion testing rig using a mix of F-1200 SiC particles with deionized water as abrasive slurry. The obtained wear rates for FeB and Fe2B phases and for the 316L stainless steel were compared. Wear resistance of 316L stainless steel increases after boriding. The wear mechanisms for both phases and for the stainless steel were identified. Also, transient conditions for rolling and grooving abrasion were determined for the FeB and Fe2B phases.

  18. 2017 Accomplishments – Tritium Aging Studies on Stainless Steel Weldments and Heat-Affected Zones

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Morgan, Michael J.; Hitchcock, Dale; Krentz, Tim

    In this study, the combined effects tritium and decay helium in forged and welded Types 304L and 21-6-9 stainless steels were studied. To measure these effects, fracture mechanic specimens were thermally precharged with tritium and aged for approximately 17 years to build in decay helium from tritium decay prior to testing. The results are compared to earlier measurements on the same alloys and weldments (4-5, 8-9). In support of Enhanced Surveillance, “Tritium Effects on Materials”, the fracture toughness properties of long-aged tritium-charged stainless-steel base metals and weldments were measured and compared to earlier measurements. The fracture-toughness data were measured bymore » thermally precharging as-forged and as-welded specimens with tritium gas at 34.5 MPa and 350°C and aging for approximately 17 years to build-in decay helium prior to testing. These data result from the longest aged specimens ever tested in the history of the tritium effects programs at Savannah River and the fracture toughness values measured were the lowest ever recorded for tritium-exposed stainless steel. For Type 21-6-9 stainless steel, fracture toughness values were reduced to less than 2-4% of the as-forged values to 41 lbs / in specimens that contained more than 1300 appm helium from tritium decay. The fracture toughness properties of long-aged weldments were also measured. The fracture toughness reductions were not as severe because the specimens did not retain as much tritium from the charging and aging as did the base metals. For Type 304L weldments, the specimens in this study contained approximately 600 appm helium and their fracture toughness values averaged 750 lbs / in. The results for other steels and weldments are reported and additional tests will be conducted during FY18.« less

  19. Effects of simulated inflammation on the corrosion of 316L stainless steel.

    PubMed

    Brooks, Emily K; Brooks, Richard P; Ehrensberger, Mark T

    2017-02-01

    Stainless steel alloys, including 316L, find use in orthopaedics, commonly as fracture fixation devices. Invasive procedures involved in the placement of these devices will provoke a local inflammatory response that produces hydrogen peroxide (H 2 O 2 ) and an acidic environment surrounding the implant. This study assessed the influence of a simulated inflammatory response on the corrosion of 316L stainless steel. Samples were immersed in an electrolyte representing either normal or inflammatory physiological conditions. After 24h of exposure, electrochemical impedance spectroscopy (EIS) and inductively coupled plasma mass spectroscopy (ICPMS) were used to evaluate differences in corrosion behavior and ion release induced by the inflammatory conditions. Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) were used to evaluate surface morphology and corrosion products formed on the sample surface. Inflammatory conditions, involving the presence of H 2 O 2 and an acidic pH, significantly alter the corrosion processes of 316L stainless steel, promoting aggressive and localized corrosion. It is demonstrated that particular consideration should be given to 316L stainless steel implants with crevice susceptible areas (ex. screw-head/plate interface), as those areas may have an increased probability of rapid and aggressive corrosion when exposed to inflammatory conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. 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

    2016-12-01

    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.

  1. Microstructural studies of hydrogen damage in metastable stainless steels. Ph.D. Thesis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, S.

    1994-12-31

    The primary objective of this dissertation is to determine the role of microstructure in hydrogen-induced damage in austenitic stainless steels. Specific attention was focused on the interactions between hydrogen and the austenitic grain, twin boundaries and the matrix, and the associated phase transformations. An experimental program of research was conducted to determine the phase transformation and cracking path in hydrogen charged stainless steels. Normal-purity AISI 304 (Fe18CrYNi) and high-purity 305 (Fe18Cr12Ni) solution-annealet stainless steels were examined. The steels were cathodically charged with hydrogen at 1, 10 and 100 mA/sq cm at room temperature for 5 min. to 32 hours, inmore » an 1N H2SO4 solution with 0.25 g/l of NaAsO2 added as a hydrogen recombination poison. Resultant changes in microstructure and hydrogen damage due to charging and subsequent room temperature aging were studied by x-ray diffraction, optical microscope (in the Nomarski mode), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A new phase in 305 stainless steel was observed, and was identified as an epsilon(*) (hcp) hydride due to hydrogen charging. Two new phases in 304 stainless steel were found as gamma(*) (fcc) and epsilon(*) hydrides from hydrogen charging. The hydride formation mechanisms during charging were: (1) gamma yields gamma(*) hydride and (2) gamma yields epsilon yields epsilon(*) hydride. These hydrides are unstable and decomposed during room temperature aging in air. The decomposition mechanisms were: (1) epsilon(*) hydride (hcp) yields expanded epsilon (hcp) phase yields a (bcc) phase; (2) gamma(*) hydride yields gamma phase. The grain and twin boundary cracks were the results of charging and identified as the preferred cracking sites. Transgranular crack initiation and growth accompanied the decomposition of hydrides and were controlled by hydrogen outgassing during room temperature aging.« less

  2. Fatigue Crack Propagation from Notched Specimens of 304 SS in elevated Temperature Aqueous Environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wire, G. L.; Mills, W. J.

    2002-08-01

    Fatigue crack propagation (FCP) rates for 304 stainless steel (304SS) were determined in 24 degree C and 288 degree C air and 288 degree C water using double-edged notch (DEN) specimens of 304 stainless steel (304 SS). Test performed at matched loading conditions in air and water at 288 degree C with 20-6- cc h[sub]2/kg h[sub]2O provided a direct comparison of the relative crack growth rates in air and water over a wide range of crack growth rates. The DEN crack extension ranged from short cracks (0.03-0.25 mm) to long cracks up to 4.06 mm, which are consistent with conventionalmore » deep crack tests. Crack growth rates of 304 SS in water were about 12 times the air rate. This 12X environmental enhancement persisted to crack extensions up to 4.06 mm, far outside the range associated with short crack effects. The large environmental degradation for 304 SS crack growth is consistent with the strong reduction of fatigue life in high hydrogen water. Further, very similar environmental effects w ere reported in fatigue crack growth tests in hydrogen water chemistry (HWC). Most literature data in high hydrogen water show only a mild environmental effect for 304 SS, of order 2.5 times air or less, but the tests were predominantly performed at high cyclic stress intensity or equivalently, high air rates. The environmental effect in low oxygen environments at low stress intensity depends strongly on both the stress ratio, R, and the load rise time, T[sub]r, as recently reported for austenitic stainless steel in BWR water. Fractography was performed for both tests in air and water. At 288 degree C in water, the fracture surfaces were crisply faceted with a crystallographic appearance, and showed striations under high magnification. The cleavage-like facets on the fracture surfaces suggest that hydrogen embrittlement is the primary cause of accelerated cracking.« less

  3. 3D ZnIn2S4 nanosheet/TiO2 nanowire arrays and their efficient photocathodic protection for 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Sun, Wenxia; Wei, Na; Cui, Hongzhi; Lin, Yuan; Wang, Xinzhen; Tian, Jian; Li, Jian; Wen, Jing

    2018-03-01

    A well-designed heterostructure engineered ZnIn2S4 nanosheet/TiO2 nanowire arrays photoanode is investigated for photocathodic protection. The ZnIn2S4 nanosheets are distributed uniformly on the surface of the TiO2 nanowire by a hydrothermal method. The stem-and-leaf-like ZnIn2S4 nanosheet/TiO2 nanowire arrays exhibit excellent photoelectrochemical properties, owing to the energy band structure and large surface area. A maximum photocurrent density of 2 mA cm-2 is achieved for the ZnIn2S4 nanosheet/TiO2 nanowire composite film for a 6 h reaction time under white illumination. Moreover, the potential of the 304 stainless steel coupled with the composite film immediately shifts negatively to -1.17 V (vs. SCE), which is significantly lower than the corrosion potential (-0.201 V vs. SCE). Thus, the composite film offers a superior photocathodic protection for stainless steel against corrosion by a NaCl solution. This study provides a promising approach for the design and synthesis of composite films with enhanced photoelectrochemical performance.

  4. Anti-biofilm formation of a novel stainless steel against Staphylococcus aureus.

    PubMed

    Nan, Li; Yang, Ke; Ren, Guogang

    2015-06-01

    Staphylococcus aureus (S. aureus) is a bacterium frequently found proliferating on metal surfaces such as stainless steels used in healthcare and food processing facilities. Past research has shown that a novel Cu-bearing 304 type stainless steel (304CuSS) exhibits excellent antibacterial ability (i.e. against S. aureus) in a short time period (24h.). This work was dedicated to investigate the 304CuSS's inhibition ability towards the S. aureus biofilm formation for an extended period of 7days after incubation. It was found that the antibacterial rate of the 304CuSS against sessile bacterial cells reached over 99.9% in comparison with the 304SS. The thickness and sizes of the biofilms on the 304SS surfaces increased markedly with period of contact, and thus expected higher risk of bio-contamination, indicated by the changes of surface free energy between biofilm and the steel surfaces. The results demonstrated that the 304CuSS exhibited strong inhibition on the growth and adherence of the biofilms. The surface free energy of the 304CuSS after contact with sessile bacterial cells was much lower than that of the 304SS towards the same culture times. The continuously dissolved Cu(2+) ions well demonstrated the dissolution ability of Cu-rich precipitates after exposure to S. aureus solution, from 3.1ppm (2days) to 4.5ppm (7days). For this to occur, a hypothesis mechanism might be established for 304CuSS in which the Cu(2+) ions were released from Cu-rich phases that bond with extracellular polymeric substances (EPS) of the microorganisms. And these inhibited the activities of cell protein/enzymes and effectively prevented planktonic bacterial cells attaching to the 304CuSS metal surface. Copyright © 2015. Published by Elsevier B.V.

  5. Experimental measurement of stationary SS 304, SS 316L and 8630 GTA weld pool surface temperatures

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kraus, H.G.

    1989-07-01

    The optical spectral radiometric/laser reflectance experimental method, previously developed by the author, was extended to obtain high-resolution surface temperature maps of stationary GTA molten weld pools using thick-plate SS 304, SS316L, and 8630 steel. Increasing the welding current from 50 to 200 A resulted in peak pool surface temperatures from 1050{sup 0} to 2400{sup 0}C for the SS 304. At a constant welding current of 150 A, the SS 304 and various heats of SS 316L and 8630 resulted in peak weld pool temperatures from 2300{sup 0} to 2700{sup 0}C. Temperature contour plots of all the welds made are given.more » Surface temperature maps are classified into types that are believed to be indicative of the convective circulation patterns present in the weld pools.« less

  6. Characterization of Friction Welded Titanium Alloy and Stainless Steel with a Novel Interlayer Geometry

    NASA Astrophysics Data System (ADS)

    Kumar, R.; Balasubramanian, M.

    The main purpose of the current research work is to identify and investigate a novel method of holding an intermediate metal and to evaluate its metallurgical and mechanical properties. Copper was used as an interlayer material for the welding of this dissimilar Ti-6Al-4V (Ti alloy) and 304L stainless steel (SS). The study shows that the input parameters and surface geometry played a very significant role in producing a good quality joints with minimum heat affected zone and metal loss. A sound weld was achieved between Ti-6Al-4V and SS304L, on the basis of the earlier experiments conducted by the authors in their laboratory, by using copper rod as intermediate metal. Box-Behnken method was used for performing a minimum number of experiments for the study. In the present study, Ti-6Al-4V alloy and SS304L were joined by a novel method of holding the interlayer and new surface geometry for the interlayer. Initially, the drop test was used for determining the quality of the fabricated joint and, subsequently, non-destructive techniques like radiography and C-scan were used. Further optical micrograph, SEM-EDS, hardness and tensile test were done for understanding the performance of the joint.

  7. Electron mediators accelerate the microbiologically influenced corrosion of 304 stainless steel by the Desulfovibrio vulgaris biofilm.

    PubMed

    Zhang, Peiyu; Xu, Dake; Li, Yingchao; Yang, Ke; Gu, Tingyue

    2015-02-01

    In the microbiologically influenced corrosion (MIC) caused by sulfate reducing bacteria (SRB), iron oxidation happens outside sessile cells while the utilization of the electrons released by the oxidation process for sulfate reduction occurs in the SRB cytoplasm. Thus, cross-cell wall electron transfer is needed. It can only be achieved by electrogenic biofilms. This work hypothesized that the electron transfer is a bottleneck in MIC by SRB. To prove this, MIC tests were carried out using 304 stainless steel coupons covered with the Desulfovibrio vulgaris (ATCC 7757) biofilm in the ATCC 1249 medium. It was found that both riboflavin and flavin adenine dinucleotide (FAD), two common electron mediators that enhance electron transfer, accelerated pitting corrosion and weight loss on the coupons when 10ppm (w/w) of either of them was added to the culture medium in 7-day anaerobic lab tests. This finding has important implications in MIC forensics and biofilm synergy in MIC that causes billions of dollars of damages to the US industry each year. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Corrosion-free precast prestressed concrete piles made with stainless steel reinforcement : construction, test and evaluation.

    DOT National Transportation Integrated Search

    2015-03-01

    The use of duplex high-strength stainless steel (HSSS) grade 2205 prestressing strand and : austenitic stainless steel (SS) grade 304 spiral wire reinforcement is proposed as a replacement of : conventional prestressing steel, in order to provide a 1...

  9. Effect of post-irradiation annealing on the irradiated microstructure of neutron-irradiated 304L stainless steel

    NASA Astrophysics Data System (ADS)

    Jiao, Z.; Hesterberg, J.; Was, G. S.

    2018-03-01

    Post-irradiation annealing was performed on a 304L SS that was irradiated to 5.9 dpa in the Barsebäck 1 BWR reactor. Evolution of dislocation loops, radiation-induced solute clusters and radiation-induced segregation at the grain boundary was investigated following thermal annealing at 500 °C and 550 °C up to 20 h. Dislocation loops, Ni-Si and Al-Cu clusters, and enrichment of Ni, Si and depletion of Cr at the grain boundary were observed in the as-irradiated condition. Dislocation loop size did not change significantly after annealing at 550 °C for 5 h but the loop number density decreased considerably and loops mostly disappeared after annealing at 550 °C for 20 h. The average size of Ni-Si and Al-Cu clusters increased while the number density decreased with annealing. The increase in cluster size was due to diffusion of solutes rather than cluster coarsening. Significant volume fractions of Ni-Si and Al-Cu clusters still remained after annealing at 550 °C for 20 h. Substantial recovery of Cr and Ni at the grain boundary was observed after annealing at 550 °C for 5 h but neither Cr nor Ni was fully recovered after 20 h. Annihilation of dislocation loops, driven by the thermal vacancy concentration gradient caused by the strain field and stacking fault associated with the loops appeared to be faster than annihilation of solute clusters and recovery of Ni and Si at the grain boundary, both of which are driven by the solute concentration gradients.

  10. Evaluation of Thymus vulgaris plant extract as an eco-friendly corrosion inhibitor for stainless steel 304 in acidic solution by means of electrochemical impedance spectroscopy, electrochemical noise analysis and density functional theory.

    PubMed

    Ehsani, A; Mahjani, M G; Hosseini, M; Safari, R; Moshrefi, R; Mohammad Shiri, H

    2017-03-15

    Inhibition performance of Thymus vulgaris plant leaves extract (thyme) as environmentally friendly (green) inhibitor for the corrosion protection of stainless steel (SS) type 304 in 1.0molL -1 HCl solution was studied by potentiodynamic polarization, electrochemical impedance (EIS) and electrochemical noise measurements (EN) techniques. The EN data were analyzed with FFT technique to make the spectral power density plots. The calculations were performed by MATLAB 2014a software. Geometry optimization and calculation of the structural and electronic properties of the molecular system of inhibitor have been carried out using UB3LYP/6-311++G ∗∗ level. Moreover, the results obtained from electrochemical noise analysis were compared with potentiodynamic polarization and electrochemical impedance spectroscopy. All of the used techniques showed positive effect of green inhibitor with increasing inhibitor concentration. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Stainless Steel Permeability

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Buchenauer, Dean A.; Karnesky, Richard A.

    An understanding of the behavior of hydrogen isotopes in materials is critical to predicting tritium transport in structural metals (at high pressure), estimating tritium losses during production (fission environment), and predicting in-vessel inventory for future fusion devices (plasma driven permeation). Current models often assume equilibrium diffusivity and solubility for a class of materials (e.g. stainless steels or aluminum alloys), neglecting trapping effects or, at best, considering a single population of trapping sites. Permeation and trapping studies of the particular castings and forgings enable greater confidence and reduced margins in the models. For FY15, we have continued our investigation of themore » role of ferrite in permeation for steels of interest to GTS, through measurements of the duplex steel 2507. We also initiated an investigation of the permeability in work hardened materials, to follow up on earlier observations of unusual permeability in a particular region of 304L forgings. Samples were prepared and characterized for ferrite content and coated with palladium to prevent oxidation. Issues with the poor reproducibility of measurements at low permeability were overcome, although the techniques in use are tedious. Funding through TPBAR and GTS were secured for a research grade quadrupole mass spectrometer (QMS) and replacement turbo pumps, which should improve the fidelity and throughput of measurements in FY16.« less

  12. Corrosion of stainless steels in the riser during co-processing of bio-oils in a fluid catalytic cracking pilot plant

    DOE PAGES

    Brady, M. P.; Keiser, J. R.; Leonard, D. N.; ...

    2017-01-31

    Co-processing of bio-oils with conventional petroleum-based feedstocks is an attractive initial option to make use of renewable biomass as a fuel source while leveraging existing refinery infrastructures. But, bio-oils and their processing intermediates have high concentrations of organic oxygenates, which, among their other negative qualities, can result in increased corrosion issues. A range of stainless steel alloys (409, 410, 304L, 316L, 317L, and 201) was exposed at the base of the riser in a fluid catalytic cracking pilot plant while co-processing vacuum gas oil with pine-derived pyrolysis bio-oils that had been catalytically hydrodeoxygenated to ~ 2 to 28% oxygen. Wemore » studied the processing using a catalyst temperature of 704 °C, a reaction exit temperature of 520 °C, and total co-processing run times of 57–75 h. External oxide scaling 5–30 μm thick and internal attack 1–5 μm deep were observed in these short-duration exposures. The greatest extent of internal attack was observed for co-processing with the least stabilized bio-oil, and more so for types 409, 410, 304L, 316L, 317L stainless steel than for type 201. Finally, the internal attack involved porous Cr-rich oxide formation, associated with local Ni-metal enrichment and S-rich nanoparticles, primarily containing Cr or Mn. Implications for alloy selection and corrosion are discussed.« less

  13. Corrosion of stainless steels in the riser during co-processing of bio-oils in a fluid catalytic cracking pilot plant

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brady, M. P.; Keiser, J. R.; Leonard, D. N.

    Co-processing of bio-oils with conventional petroleum-based feedstocks is an attractive initial option to make use of renewable biomass as a fuel source while leveraging existing refinery infrastructures. But, bio-oils and their processing intermediates have high concentrations of organic oxygenates, which, among their other negative qualities, can result in increased corrosion issues. A range of stainless steel alloys (409, 410, 304L, 316L, 317L, and 201) was exposed at the base of the riser in a fluid catalytic cracking pilot plant while co-processing vacuum gas oil with pine-derived pyrolysis bio-oils that had been catalytically hydrodeoxygenated to ~ 2 to 28% oxygen. Wemore » studied the processing using a catalyst temperature of 704 °C, a reaction exit temperature of 520 °C, and total co-processing run times of 57–75 h. External oxide scaling 5–30 μm thick and internal attack 1–5 μm deep were observed in these short-duration exposures. The greatest extent of internal attack was observed for co-processing with the least stabilized bio-oil, and more so for types 409, 410, 304L, 316L, 317L stainless steel than for type 201. Finally, the internal attack involved porous Cr-rich oxide formation, associated with local Ni-metal enrichment and S-rich nanoparticles, primarily containing Cr or Mn. Implications for alloy selection and corrosion are discussed.« less

  14. 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.

  15. Interaction of Desulfovibrio desulfuricans biofilms with stainless steel surface and its impact on bacterial metabolism.

    PubMed

    Lopes, F A; Morin, P; Oliveira, R; Melo, L F

    2006-11-01

    To study the influence of some metallic elements of stainless steel 304 (SS 304) on the development and activity of a sulfate-reducing bacterial biofilm, using as comparison a reference nonmetallic material polymethylmethacrylate (PMMA). Desulfovibrio desulfuricans biofilms were developed on SS 304 and on a reference nonmetallic material, PMMA, in a flow cell system. Steady-state biofilms were metabolically more active on SS 304 than on PMMA. Activity tests with bacteria from both biofilms at steady state also showed that the doubling time was lower for bacteria from SS 304 biofilms. The influence of chromium and nickel, elements of SS 304 composition, was also tested on a cellular suspension of Des. desulfuricans. Nickel decreased the bacterial doubling time, while chromium had no significant effect. The following mechanism is hypothesized: a Des. desulfuricans biofilm grown on a SS 304 surface in anaerobic conditions leads to the weakening of the metal passive layer and to the dissolution in the bulk phase of nickel ions that have a positive influence on the sulfate-reducing bacteria metabolism. This phenomenon may enhance the biocorrosion process. A better understanding of the interactions between metallic surfaces such as stainless steel and bacteria commonly implied in the corrosion phenomena which is primordial to fight biocorrosion.

  16. Microstructure and mechanical properties of 2024-T3 and 7075-T6 aluminum alloys and austenitic stainless steel 304 after being exposed to hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Sofyan, Nofrijon Bin Imam

    The effect of hydrogen peroxide used as a decontaminant agent on selected aircraft metallic materials has been investigated. The work is divided into three sections; bacterial attachment behavior onto an austenitic stainless steel 304 surface; effect of decontamination process on the microstructure and mechanical properties of aircraft metallic structural materials of two aluminum alloys, i.e. 2024-T3 and 7075-T6, and an austenitic stainless steel 304 as used in galley and lavatory surfaces; and copper dissolution rate into hydrogen peroxide. With respect to bacterial attachment, the results show that surface roughness plays a role in the attachment of bacteria onto metallic surfaces at certain extent. However, when the contact angle of the liquid on a surface increased to a certain degree, detachment of bacteria on that surface became more difficult. In its relation to the decontamination process, the results show that a corrosion site, especially on the austenitic stainless steel 304 weld and its surrounding HAZ area, needs more attention because it could become a source or a harborage of bio-contaminant agent after either incidental or intentional bio-contaminant delivery. On the effect of the decontamination process on the microstructure and mechanical properties of aircraft metallic structural materials, the results show that microstructural effects are both relatively small in magnitude and confined to a region immediately adjacent to the exposed surface. No systematic effect is found on the tensile properties of the three alloys under the conditions examined. The results of this investigation are promising with respect to the application of vapor phase hydrogen peroxide as a decontaminant agent to civilian aircraft, in that even under the most severe circumstances that could occur; only very limited damage was observed. The results from the dissolution of copper by concentrated liquid hydrogen peroxide showed that the rate of copper dissolution increased for

  17. The application of electrolytic photoetching and photopolishing to AISI 304 stainless steel and the electrolytic photoetching of amorphous cobalt alloy

    NASA Astrophysics Data System (ADS)

    Thomaz, Marita Duarte Canhao da Silva Pereira Fernandes

    The results presented cover broad aspects of a quantitative investigation into the elecrolytic etching and polishing of metals and alloys through photographically produced dielectric stencils (Photoresists). A study of the potential field generated between a cathode and relatively smaller anode sites as those defined by a dielectric stencil was carried out. Numerical, analytical and graphical methods yielded answers to the factors determining lateral dissolution (undercut) at the anode/stencil interface. A quasi steady state numerical model simulating the transient behavior of the partially masked electrodes undergoing dissolution was obtained. AISI 304 stainless steel was electrolytically photoetched in 10% w/w HCl electrolyte. The optimised process parameters were utilised for quantifying the effects of galvanostatic etching of the anode as that defined by a relatively narrow adherent resist stencil. Stainless steel was also utilised in investigating electrolytic photopolishing. A polishing electrolyte (orthophosphoric acid-glycerol) was modified by the addition of a surfactant which yielded surface texture values of 70nm (Ra) and high levels of specular reflectance. These results were used in the production of features upon the metal surface through photographically produced precision stencils. The process was applied to the production of edge filters requiring high quality surface textures in precision recesses. Some of the new amorphous material exhibited high resistance to dissolution in commercially used spray etching formulations. One of these materials is a cobalt based alloy produced by chill block spinning. This material was also investigated and electro etched in 10% w/w HCl solution. Although passivity was not overcome, by selecting suitable operating parameters the successful electro photoetching of precision magnetic recording head laminations was achieved. Similarly, a polycrystalline nickel based alloy also exhibiting passivity in commercially used

  18. Electroless nickel plating on stainless steels and aluminum

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Procedures for applying an adherent electroless nickel plating on 303 SE, 304, and 17-7 PH stainless steels, and 7075 aluminum alloy was developed. When heat treated, the electroless nickel plating provides a hard surface coating on a high strength, corrosion resistant substrate.

  19. Erosion-corrosion resistance properties of 316L austenitic stainless steels after low-temperature liquid nitriding

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangfeng; Wang, Jun; Fan, Hongyuan; Pan, Dong

    2018-05-01

    The low-temperature liquid nitriding of stainless steels can result in the formation of a surface zone of so-called expanded austenite (S-phase) by the dissolution of large amounts of nitrogen in the solid solution and formation of a precipitate-free layer supersaturated with high hardness. Erosion-corrosion measurements were performed on low-temperature nitrided and non-nitrided 316L stainless steels. The total erosion-corrosion, erosion-only, and corrosion-only wastages were measured directly. As expected, it was shown that low-temperature nitriding dramatically reduces the degree of erosion-corrosion in stainless steels, caused by the impingement of particles in a corrosive medium. The nitrided 316L stainless steels exhibited an improvement of almost 84% in the erosion-corrosion resistance compared to their non-nitrided counterparts. The erosion-only rates and synergistic levels showed a general decline after low-temperature nitriding. Low-temperature liquid nitriding can not only reduce the weight loss due to erosion but also significantly reduce the weight loss rate of interactions, so that the total loss of material decreased evidently. Therefore, 316L stainless steels displayed excellent erosion-corrosion behaviors as a consequence of their highly favorable corrosion resistances and superior wear properties.

  20. The Investigation of Strain-Induced Martensite Reverse Transformation in AISI 304 Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Cios, G.; Tokarski, T.; Żywczak, A.; Dziurka, R.; Stępień, M.; Gondek, Ł.; Marciszko, M.; Pawłowski, B.; Wieczerzak, K.; Bała, P.

    2017-10-01

    This paper presents a comprehensive study on the strain-induced martensitic transformation and reversion transformation of the strain-induced martensite in AISI 304 stainless steel using a number of complementary techniques such as dilatometry, calorimetry, magnetometry, and in-situ X-ray diffraction, coupled with high-resolution microstructural transmission Kikuchi diffraction analysis. Tensile deformation was applied at temperatures between room temperature and 213 K (-60 °C) in order to obtain a different volume fraction of strain-induced martensite (up to 70 pct). The volume fraction of the strain-induced martensite, measured by the magnetometric method, was correlated with the total elongation, hardness, and linear thermal expansion coefficient. The thermal expansion coefficient, as well as the hardness of the strain-induced martensitic phase was evaluated. The in-situ thermal treatment experiments showed unusual changes in the kinetics of the reverse transformation (α' → γ). The X-ray diffraction analysis revealed that the reverse transformation may be stress assisted—strains inherited from the martensitic transformation may increase its kinetics at the lower annealing temperature range. More importantly, the transmission Kikuchi diffraction measurements showed that the reverse transformation of the strain-induced martensite proceeds through a displacive, diffusionless mechanism, maintaining the Kurdjumov-Sachs crystallographic relationship between the martensite and the reverted austenite. This finding is in contradiction to the results reported by other researchers for a similar alloy composition.

  1. Irradiation-induced sensitization and stress corrosion cracking of Type 304 stainless steel core-internal components

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chung, H.M.; Ruther, W.E.; Sanecki, J.E.

    1991-08-01

    High- and commercial-purity heats of Type 304 stainless steel, obtained from neutron absorber tubes after irradiation to fluence levels of up to 2 {times} 10{sup 21} n{center dot}cm{sup {minus}2} (E > 1 MeV) in two boiling water reactors, were examined by Auger electron spectroscopy to characterize irradiation-induced grain- boundary segregation and depletion of alloying and impurity elements. Segregation of Si, P, Ni, and an unidentified element or compound that gives rise to an Auger energy peak at 59 eV was observed in the commercial-purity heat. Such segregation was negligible in high-purity material, except for Ni. No evidence of S segregationmore » was observed in either material. Cr depletion was more pronounced in the high-purity material than in the commercial-purity material. These observations suggest a synergism between the significant level of impurities and Cr depletion in the commercial-purity heat. In the absence of such synergism, Cr depletion appears more pronounced in the high-purity heat. Initial results of constant-extension-rate tests conducted on the two heats in air an in simulated BWR water were correlated with the results from analysis by Auger electron spectroscopy. 15 refs., 10 figs.« less

  2. Damage Analysis of Tensile Deformation of Co-rolled SMATed 304SS

    NASA Astrophysics Data System (ADS)

    Guo, X.; Leung, A. Y. T.; Chen, A.; Ruan, H.; Lu, J.

    2010-05-01

    One of recent experimental progresses in strengthening and toughening metals simultaneously is to adopt techniques of surface mechanical attrition treatment (SMAT) and warm co-rolling to 304 stainless steel (SS). To capture deformation behavior and associated damage initiation/evolution process in the co-rolled SMATed 304SS, cohesive finite element method (CFEM) is employed in this paper and simulation results are in agreement with experimental results. Both strengthening effect due to high yield stress of the nanograin layer and toughening effect due to non-localized damage in the nanograin layer are captured. Effect of energy release rate of nanograin layer on failure strain of layered co-rolled SMATed 304SS is investigated. It is found that the more brittle the nanograin layer is, the more potential necking sites in the nanograin layer are, and the more ductile the layered co-rolled SMATed 304SS is.

  3. 2016 Accomplishments. Tritium aging studies on stainless steel. Forging process effects on the fracture toughness properties of tritium-precharged stainless steel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Morgan, Michael J.

    Forged austenitic stainless steels are used as the materials of construction for pressure vessels designed to contain tritium at high pressure. These steels are highly resistant to tritium-assisted fracture but their resistance can depend on the details of the forging microstructure. During FY16, the effects of forging strain rate and deformation temperature on the fracture toughness properties of tritium-exposed-and-aged Type 304L stainless steel were studied. Forgings were produced from a single heat of steel using four types of production forging equipment – hydraulic press, mechanical press, screw press, and high-energy-rate forging (HERF). Each machine imparted a different nominal strain ratemore » during the deformation. The objective of the study was to characterize the J-Integral fracture toughness properties as a function of the industrial strain rate and temperature. The second objective was to measure the effects of tritium and decay helium on toughness. Tritium and decay helium effects were measured by thermally precharging the as-forged specimens with tritium gas at 34.5 MPa and 350°C and aging for up to five years at -80°C to build-in decay helium prior to testing. The results of this study show that the fracture toughness properties of the as-forged steels vary with forging strain rate and forging temperature. The effect is largely due to yield strength as the higher-strength forgings had the lower toughness values. For non-charged specimens, fracture toughness properties were improved by forging at 871°C versus 816°C and Screw-Press forgings tended to have lower fracture toughness values than the other forgings. Tritium exposures reduced the fracture toughness values remarkably to fracture toughness values averaging 10-20% of as-forged values. However, forging strain rate and temperature had little or no effect on the fracture toughness after tritium precharging and aging. The result was confirmed by fractography which indicated that

  4. Electrochemical Carbonitriding of 316L Stainless Steel in Molten Salt System

    NASA Astrophysics Data System (ADS)

    Ren, Yanjie; Xiao, Bo; Chen, Yaqing; Chen, Jian; Chen, Jianlin

    This paper reports an electrochemical route for carbonitriding 316L stainless steel in molten salts. Carbonitriding process was accomplished in molten alkaline chloride (LiCl/KCl) with the addition of KNO2 at 480∘C using a three-electrode system in which a carbon sheet was the counter electrode. The carbonitriding layer of 316L stainless steel obtained by potentiostatic electrolysis was analyzed by several physical techniques. The results showed that a compact layer with a thickness of about 7μm formed after the treatment. According to X-ray diffraction analysis, chromium nitride and carbide formed on the surface of carbonitriding layer. The microhardness of the carbonitriding layer is HV 336, as compared to HV 265 for the substrate.

  5. Effects of External Hydrogen on Hydrogen Transportation and Distribution Around the Fatigue Crack Tip in Type 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Chen, Xingyang; Zhou, Chengshuang; Cai, Xiao; Zheng, Jinyang; Zhang, Lin

    2017-10-01

    The effects of external hydrogen on hydrogen transportation and distribution around the fatigue crack tip in type 304 stainless steel were investigated by using hydrogen microprint technique (HMT) and thermal desorption spectrometry. HMT results show that some silver particles induced by hydrogen release are located near the fatigue crack and more silver particles are concentrated around the crack tip, which indicates that hydrogen accumulates in the vicinity of the crack tip during the crack growth in hydrogen gas environment. Along with the crack propagation, strain-induced α' martensite forms around the crack tip and promotes hydrogen invasion into the matrix, which will cause the crack initiation and propagation at the austenite/ α' martensite interface. In addition, the hydrogen content in the vicinity of the crack tip is higher than that at the crack edge far away from the crack tip, which is related to the stress state and strain-induced α' martensite.

  6. A study on corrosion resistance of dissimilar welds between Monel 400 and 316L austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Mani, Cherish; Karthikeyan, R.; Vincent, S.

    2018-04-01

    An attempt has been made to study the corrosion resistance of bi-metal weld joints of Monel 400 tube to stainless steel 316 tube by GTAW process. The present research paper contributes to the ongoing research work on the use of Monel400 and 316L austenitic stainless steel in industrial environments. Potentiodynamic method is used to investigate the corrosion behavior of Monel 400 and 316L austenitic stainless steel welded joints. The analysis has been performed on the base metal, heat affected zone and weld zone after post weld heat treatment. Optical microscopy was also performed to correlate the results. The heat affected zone of Monel 400 alloy seems to have the lowest corrosion resistance whereas 316L stainless steel base metal has the highest corrosion resistance.

  7. Effect of Annealing Treatment on Σ3-Type CSL Boundaries and Its Interactions in 304HCu Grade Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Dash, Manmath Kumar; Mythili, R.; Dasgupta, Arup; Saroja, S.

    2018-04-01

    This paper presents the results of a study on grain boundary characteristics in cold deformed and annealed 304HCu grade austenitic stainless steel (SS 304HCu) using electron backscatter diffraction. The microstructure exhibited an increasing fraction of Σ1 to 29 coincidence site lattice boundaries with annealing temperature, resulting up to 60 pct at 1573 K with 92 pct contribution from Σ3-type twin boundary. However, the twin boundary interaction at the triple points with a network of Σ3-Σ3-Σ9 was found to decrease from 4 to 0.5 pct with annealing temperature. To understand the resultant boundary advancement of the Σ3 n (n = 1, 2, 3) boundaries, their migration was traced in the annealed specimen. However, in the specimen with extended annealing Σ3 boundary fraction was found to be higher with a concomitant decrease in the boundary fraction generated by the Σ3 interactions. In this study, a procedure to analyze the coherency of Σ3 boundaries and its interfaces that form due to Σ3 interactions has been evolved based on single-section analysis using the pole concentration across the grains. Further, a crystallographic description of the two planes meeting at the interface of Σ3-type boundary has been provided by adopting serial sectioning methods, which help to understand the morphological changes. The quantitative deviation from exact coherent Σ3 has been estimated to be within 6 deg in this study.

  8. Effect of Annealing Treatment on Σ3-Type CSL Boundaries and Its Interactions in 304HCu Grade Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Dash, Manmath Kumar; Mythili, R.; Dasgupta, Arup; Saroja, S.

    2018-07-01

    This paper presents the results of a study on grain boundary characteristics in cold deformed and annealed 304HCu grade austenitic stainless steel (SS 304HCu) using electron backscatter diffraction. The microstructure exhibited an increasing fraction of Σ1 to 29 coincidence site lattice boundaries with annealing temperature, resulting up to 60 pct at 1573 K with 92 pct contribution from Σ3-type twin boundary. However, the twin boundary interaction at the triple points with a network of Σ3-Σ3-Σ9 was found to decrease from 4 to 0.5 pct with annealing temperature. To understand the resultant boundary advancement of the Σ3 n ( n = 1, 2, 3) boundaries, their migration was traced in the annealed specimen. However, in the specimen with extended annealing Σ3 boundary fraction was found to be higher with a concomitant decrease in the boundary fraction generated by the Σ3 interactions. In this study, a procedure to analyze the coherency of Σ3 boundaries and its interfaces that form due to Σ3 interactions has been evolved based on single-section analysis using the pole concentration across the grains. Further, a crystallographic description of the two planes meeting at the interface of Σ3-type boundary has been provided by adopting serial sectioning methods, which help to understand the morphological changes. The quantitative deviation from exact coherent Σ3 has been estimated to be within 6 deg in this study.

  9. Strain-induced phase transformation at the surface of an AISI-304 stainless steel irradiated to 4.4 dpa and deformed to 0.8% strain

    NASA Astrophysics Data System (ADS)

    Gussev, M. N.; Field, K. G.; Busby, J. T.

    2014-03-01

    Surface relief due to localized deformation in a 4.4-dpa neutron-irradiated AISI 304 stainless steel was investigated using scanning electron microscopy coupled with electron backscattering diffraction and scanning transmission electron microscopy. It was found a body-centered-cubic (BCC) phase (deformation-induced martensite) had formed at the surface of the deformed specimen along the steps generated from dislocation channels. Martensitic hill-like formations with widths of ˜1 μm and depths of several microns were observed at channels with heights greater than ˜150 nm above the original surface. Martensite at dislocation channels was observed in grains along the [0 0 1]-[1 1 1] orientation but not in those along the [1 0 1] orientation.

  10. Effect of Ultrasonic Nano-Crystal Surface Modification (UNSM) on the Passivation Behavior of Aged 316L Stainless Steel

    PubMed Central

    Kim, Ki-Tae; Lee, Jung-Hee; Kim, Young-Sik

    2017-01-01

    Stainless steels have good corrosion resistance in many environments but welding or aging can decrease their resistance. This work focused on the effect of aging time and ultrasonic nano-crystal surface modification on the passivation behavior of 316L stainless steel. In the case of slightly sensitized 316L stainless steel, increasing the aging time drastically decreased the pitting potential, increased the passive current density, and decreased the resistance of the passive film, even though aging did not form chromium carbide and a chromium depletion zone. This behavior is due to the micro-galvanic corrosion between the matrix and carbon segregated area, and this shows the importance of carbon segregation in grain boundaries to the pitting corrosion resistance of stainless steel, in addition to the formation of the chromium depletion zone. UNSM (Ultrasonic Nano Crystal Surface Modification)-treatment to the slightly sensitized 316L stainless steel increased the pitting potential, decreased the passive current density, and increased the resistance of the passive film. However, in the case of heavily sensitized 316L stainless steel, UNSM-treatment decreased the pitting potential, increased the passive current density, and decreased the resistance of the passive film. This behavior is due to the dual effects of the UNSM-treatment. That is, the UNSM-treatment reduced the carbon segregation, regardless of whether the stainless steel 316L was slightly or heavily sensitized. However, since this treatment made mechanical flaws in the outer surface in the case of the heavily sensitized stainless steel, UNSM-treatment may eliminate chromium carbide, and this flaw can be a pitting initiation site, and therefore decrease the pitting corrosion resistance. PMID:28773067

  11. Effect of Ultrasonic Nano-Crystal Surface Modification (UNSM) on the Passivation Behavior of Aged 316L Stainless Steel.

    PubMed

    Kim, Ki-Tae; Lee, Jung-Hee; Kim, Young-Sik

    2017-06-27

    Stainless steels have good corrosion resistance in many environments but welding or aging can decrease their resistance. This work focused on the effect of aging time and ultrasonic nano-crystal surface modification on the passivation behavior of 316L stainless steel. In the case of slightly sensitized 316L stainless steel, increasing the aging time drastically decreased the pitting potential, increased the passive current density, and decreased the resistance of the passive film, even though aging did not form chromium carbide and a chromium depletion zone. This behavior is due to the micro-galvanic corrosion between the matrix and carbon segregated area, and this shows the importance of carbon segregation in grain boundaries to the pitting corrosion resistance of stainless steel, in addition to the formation of the chromium depletion zone. UNSM (Ultrasonic Nano Crystal Surface Modification)-treatment to the slightly sensitized 316L stainless steel increased the pitting potential, decreased the passive current density, and increased the resistance of the passive film. However, in the case of heavily sensitized 316L stainless steel, UNSM-treatment decreased the pitting potential, increased the passive current density, and decreased the resistance of the passive film. This behavior is due to the dual effects of the UNSM-treatment. That is, the UNSM-treatment reduced the carbon segregation, regardless of whether the stainless steel 316L was slightly or heavily sensitized. However, since this treatment made mechanical flaws in the outer surface in the case of the heavily sensitized stainless steel, UNSM-treatment may eliminate chromium carbide, and this flaw can be a pitting initiation site, and therefore decrease the pitting corrosion resistance.

  12. Finite element thermal analysis for PMMA/st.st.304 laser direct joining

    NASA Astrophysics Data System (ADS)

    Hussein, Furat I.; Salloomi, Kareem N.; Akman, E.; Hajim, K. I.; Demir, A.

    2017-01-01

    This work is concerned with building a three-dimensional (3D) ab-initio models that is capable of predicting the thermal distribution of laser direct joining processes between Polymethylmethacrylate (PMMA) and stainless steel 304(st.st.304). ANSYS® simulation based on finite element analysis (FEA) was implemented for materials joining in two modes; laser transmission joining (LTJ) and conduction joining (CJ). ANSYS® simulator was used to explore the thermal environment of the joints during joining (heating time) and after joining (cooling time). For both modes, the investigation is carried out when the laser spot is at the middle of the joint width, at 15 mm from the commencement point (joint edge) at traveling time of 3.75 s. Process parameters involving peak power (Pp=3 kW), pulse duration (τ=5 ms), pulse repetition rate (PRR=20 Hz) and scanning speed (v=4 mm/s) are applied for both modes.

  13. Interfacial Microstructure and Mechanical Properties of Friction Stir Welded Joints of Commercially Pure Aluminum and 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Murugan, Balamagendiravarman; Thirunavukarasu, Gopinath; Kundu, Sukumar; Kailas, Satish V.; Chatterjee, Subrata

    2018-05-01

    In the present investigation, friction stir welding of commercially pure aluminum and 304 stainless steel was carried out at varying tool rotational speeds from 200 to 1000 rpm in steps of 200 rpm using 60 mm/min traverse speed at 2 (degree) tool tilt angle. Microstructural characterization of the interfacial zone was carried out using optical microscope and scanning electron microscope. Energy-dispersive spectroscopy indicated the presence of FeAl3 intermetallic phase. Thickness of the intermetallic layer increased with the increase in tool rotational speed. X-ray diffraction studies indicated the formation of intermetallic phases like FeAl2, Fe4Al13, Fe2Al5, and FeAl3. A maximum tensile strength of 90% that of aluminum along with 4.5% elongation was achieved with the welded sample at tool rotational speed of 400 rpm. The stir zone showed higher hardness as compared to base metals, heat affected zone, and thermo-mechanically affected zone due to the presence of intermetallics. The maximum hardness value at the stir zone was achieved at 1000 rpm tool rotational speed.

  14. Microchemical and microstructural evolution of AISI 304 stainless steel irradiated in EBR-II at PWR-relevant dpa rates

    NASA Astrophysics Data System (ADS)

    Dong, Y.; Sencer, B. H.; Garner, F. A.; Marquis, E. A.

    2015-12-01

    AISI 304 stainless steel was irradiated at 416 °C and 450 °C at a 4.4 × 10-9 and 3.05 × 10-7 dpa/s to ∼0.4 and ∼28 dpa, respectively, in the reflector of the EBR-II fast reactor. Both unirradiated and irradiated conditions were examined using standard and scanning transmission electron microscopy, energy dispersive spectroscopy, and atom probe tomography on very small specimens produced by focused ion beam milling. These results are compared with previous electron microscopy examination of 3 mm disks from essentially the same material. By comparing a very low dose specimen with a much higher dose specimen, both derived from a single reactor assembly, it has been demonstrated that the coupled microstructural and microchemical evolution of dislocation loops and other sinks begins very early, with elemental segregation producing at these sinks what appears to be measurable precursors to fully formed precipitates found at higher doses. The nature of these sinks and their possible precursors are examined in detail.

  15. Laser welding of NiTi shape memory alloy: Comparison of the similar and dissimilar joints to AISI 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Mirshekari, G. R.; Saatchi, A.; Kermanpur, A.; Sadrnezhaad, S. K.

    2013-12-01

    The unique properties of NiTi alloy, such as its shape memory effect, super-elasticity and biocompatibility, make it ideal material for various applications such as aerospace, micro-electronics and medical device. In order to meet the requirement of increasing applications, great attention has been given to joining of this material to itself and to other materials during past few years. Laser welding has been known as a suitable joining technique for NiTi shape memory alloy. Hence, in this work, a comparative study on laser welding of NiTi wire to itself and to AISI 304 austenitic stainless steel wire has been made. Microstructures, mechanical properties and fracture morphologies of the laser joints were investigated using optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD), Vickers microhardness (HV0.2) and tensile testing techniques. The results showed that the NiTi-NiTi laser joint reached about 63% of the ultimate tensile strength of the as-received NiTi wire (i.e. 835 MPa) with rupture strain of about 16%. This joint also enabled the possibility to benefit from the pseudo-elastic properties of the NiTi component. However, tensile strength and ductility decreased significantly after dissimilar laser welding of NiTi to stainless steel due to the formation of brittle intermetallic compounds in the weld zone during laser welding. Therefore, a suitable modification process is required for improvement of the joint properties of the dissimilar welded wires.

  16. Effects of Deformation Mode and Strain Level on Grain Boundary Character Distribution of 304 Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Feng, Wen; Yang, Sen; Yan, Yinbiao

    2018-06-01

    In this study, the effects of deformation mode (rolling and tension) and strain level on grain boundary character distribution were systematically investigated in 304 austenitic stainless steel. The experimental results showed that the <110> component parallel to the normal direction orientation and the P(BND) {110}<111> texture were predominant in the rolled specimens and the tensioned ones, respectively. For each mode of deformation, the fraction of low-Σ coincidence site lattice (CSL) boundaries, especially Σ3 n ( n = 1, 2, 3) boundaries decreased with the increasing strain level after annealing. At a lower strain level, the type of texture played a leading role in grain boundary reconstruction during annealing, and the <110> component parallel to the normal direction orientation facilitated the formation of low-Σ CSL boundaries during annealing compared with the P(BND) texture. However, for a higher strain level, the stored energy became dominant in grain boundary reconstruction during annealing, and a large stored energy was detrimental to the formation of low-Σ CSL boundaries, which resulted in a higher fraction of low-Σ CSL boundaries in the tensioned specimen than that in the rolled one after annealing.

  17. Deposition of magnesium nitride thin films on stainless steel-304 substrates by using a plasma focus device

    NASA Astrophysics Data System (ADS)

    Ramezani, Amir Hoshang; Habibi, Maryam; Ghoranneviss, Mahmood

    2014-08-01

    In this research, for the first time, we synthesize magnesium nitride thin films on 304-type stainless steel substrates using a Mather-type (2 kJ) plasma focus (PF) device. The films of magnesium nitride are coated with different number of focus shots (like 15, 25 and 35) at a distance of 8 cm from the anode tip and at 0° angular position with respect to the anode axis. For investigation of the structural properties and surface morphology of magnesium nitride films, we utilized the X-ray diffractometer (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM) analysis, respectively. Also, the elemental composition is characterized by energy-dispersive X-ray (EDX) analysis. Furthermore, Vicker's microhardness is used to study the mechanical properties of the deposited films. The results show that the degree of crystallinity of deposited thin films (from XRD), the average size of particles and surface roughness (from AFM), crystalline growth of structures (from SEM) and the hardness values of the films depend on the number of focus shots. The EDX analysis demonstrates the existence of the elemental composition of magnesium in the deposited samples.

  18. Novel Approach for Welding Stainless Steel Using Cr-Free Welding Consumables

    DTIC Science & Technology

    2004-12-31

    Breakdown potential ERP Repassivation potential SS Stainless steel SMAW Shielded metal arc welding GTAW Gas tungsten arc welding PEL Permissible...0.1 M NaCl. 14 4. List of Tables Table 1. Details of GTAW procedure. 7 1 5. Acknowledgements The work in this report was...resistance, filler metals matching or exceeding the chromium (Cr) content of the base metal must be used. The Cr content of Types 304 and 308 stainless

  19. Tribocorrosion Failure Mechanism of TiN/SiOx Duplex Coating Deposited on AISI304 Stainless Steel.

    PubMed

    Chen, Qiang; Xie, Zhiwen; Chen, Tian; Gong, Feng

    2016-11-26

    TiN/SiO x duplex coatings were synthesized on AISI304 stainless steel by plasma immersion ion implantation and deposition (PIIID) followed by radio frequency magnetron sputtering (RFMS). The microstructure and tribocorrosion failure behaviors of the duplex coatings were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, reciprocating-sliding tribometer, and electrochemical tests. The as-deposited duplex coating had a two-layered columnar growth structure consisting of face-centered cubic TiN and amorphous SiO x . Sliding tests showed that the TiN interlayer had good adhesion with the substrate, but the SiO x layer suffered from severe delamination failure. Friction force induced a number of micro-cracks in the coating, which provided channels for the diffusion of NaCl solution. The tribocorrosion test showed that the duplex coating exhibited a lower wear-performance in NaCl solution than in ambient atmosphere. Multi-scale chloride ion corrosion occurred simultaneously and substantially degraded the bonding strength of the columnar crystals or neighboring layers. Force-corrosion synergy damage eventually led to multi-degradation failure of the duplex coating. The presented results provide a comprehensive understanding of the tribocorrosion failure mechanism in coatings with duplex architecture.

  20. Study of the Performance of Stainless Steel A-TIG Welds

    NASA Astrophysics Data System (ADS)

    Shyu, S. W.; Huang, H. Y.; Tseng, K. H.; Chou, C. P.

    2008-04-01

    The purpose of the present work was to investigate the effect of oxide fluxes on weld morphology, arc voltage, mechanical properties, angular distortion and hot cracking susceptibility obtained with TIG welding, which applied to the welding of 5 mm thick austenitic stainless steel plates. A novel variant of the autogenous TIG welding process, oxide powders (Al2O3, Cr2O3, TiO2, SiO2 and CaO) was applied on a type 304 stainless steel through a thin layer of the flux to produce a bead on plate welds. The experimental results indicated that the increase in the penetration is significant with the use of Cr2O3, TiO2, and SiO2. A-TIG welding can increase the weld depth to bead-width ratio, and tends to reduce the angular distortion of the weldment. It was also found that A-TIG welding can increase the retained delta-ferrite content of stainless steel 304 welds and, in consequence, the hot-cracking susceptibility of as-welded is reduced. Physically constricting the plasma column and reducing the anode spot are the possible mechanism for the effect of certain flux on A-TIG penetration.

  1. Microstructural and Electrochemical Evaluation of Fusion Welded Low-Nickel and 304 SS at Different Heat Input

    NASA Astrophysics Data System (ADS)

    Bansod, Ankur V.; Patil, Awanikumar P.; Moon, Abhijeet P.; Shukla, Sourabh

    2017-12-01

    The present research study investigates the effect of heat input using E 308 electrode (controlled by welding current, i.e., 70, 85 and 100 A) on microstructure, mechanical properties and corrosion behavior of low-nickel and 304 stainless steel (SS) weldments produced by shielded metal arc welding technique. SEM investigation shows that with the higher heat input, δ-ferrite content was reduced. Dendrite and inter-dendritic length is also reduced by lowering the heat input. For all the heat inputs, it is observed that δ-ferrite content was higher in 304 stainless steel (SS) as compared to that of low-nickel austenitic stainless steel (Cr-Mn SS). Considering the heat input for Cr-Mn SS, coarse grains were observed in the heat-affected zone region. For low heat input (LHI), tensile fracture surface has exhibited river-like pattern with dimple appearance. Corrosion studies show better pitting resistance for low heat input (LHI) samples due to higher δ-ferrite present in the weld region. Similarly, higher interphase corrosion resistance is observed in both the SS grades causing more dissolution in the LHI samples.

  2. The effects of stainless steel radial reflector on core reactivity for small modular reactor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kang, Jung Kil, E-mail: jkkang@email.kings.ac.kr; Hah, Chang Joo, E-mail: changhah@kings.ac.kr; Cho, Sung Ju, E-mail: sungju@knfc.co.kr

    Commercial PWR core is surrounded by a radial reflector, which consists of a baffle and water. Radial reflector is designed to reflect neutron back into the core region to improve the neutron efficiency of the reactor and to protect the reactor vessels from the embrittling effects caused by irradiation during power operation. Reflector also helps to flatten the neutron flux and power distributions in the reactor core. The conceptual nuclear design for boron-free small modular reactor (SMR) under development in Korea requires to have the cycle length of 4∼5 years, rated power of 180 MWth and enrichment less than 5more » w/o. The aim of this paper is to analyze the effects of stainless steel radial reflector on the performance of the SMR using UO{sub 2} fuels. Three types of reflectors such as water, water/stainless steel 304 mixture and stainless steel 304 are selected to investigate the effect on core reactivity. Additionally, the thickness of stainless steel and double layer reflector type are also investigated. CASMO-4/SIMULATE-3 code system is used for this analysis. The results of analysis show that single layer stainless steel reflector is the most efficient reflector.« less

  3. A Modified Mechanical Threshold Stress Constitutive Model for Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Prasad, K. Sajun; Gupta, Amit Kumar; Singh, Yashjeet; Singh, Swadesh Kumar

    2016-12-01

    This paper presents a modified mechanical threshold stress (m-MTS) constitutive model. The m-MTS model incorporates variable athermal and dynamic strain aging (DSA) Components to accurately predict the flow stress behavior of austenitic stainless steels (ASS)-316 and 304. Under strain rate variations between 0.01-0.0001 s-1, uniaxial tensile tests were conducted at temperatures ranging from 50-650 °C to evaluate the material constants of constitutive models. The test results revealed the high dependence of flow stress on strain, strain rate and temperature. In addition, it was observed that DSA occurred at elevated temperatures and very low strain rates, causing an increase in flow stress. While the original MTS model is capable of predicting the flow stress behavior for ASS, statistical parameters point out the inefficiency of the model when compared to other models such as Johnson Cook model, modified Zerilli-Armstrong (m-ZA) model, and modified Arrhenius-type equations (m-Arr). Therefore, in order to accurately model both the DSA and non-DSA regimes, the original MTS model was modified by incorporating variable athermal and DSA components. The suitability of the m-MTS model was assessed by comparing the statistical parameters. It was observed that the m-MTS model was highly accurate for the DSA regime when compared to the existing models. However, models like m-ZA and m-Arr showed better results for the non-DSA regime.

  4. 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

  5. Enhancement of cavitation erosion resistance of 316 L stainless steel by adding molybdenum.

    PubMed

    Li, D G; Chen, D R; Liang, P

    2017-03-01

    The influence of Mo on ultrasonic cavitation erosion of 316 L stainless steel in 3.5% NaCl solution were investigated using an ultrasonic cavitation erosion (CE) facility. The morphologies of specimen after cavitation erosion were observed by scanning electron microscopy (SEM). The results showed that the addition of Mo can sharply decrease the mean depth of erosion (MDE) of 316 L SS, implying the increased resistance of cavitation erosion. In order to better understanding the influence of Mo on the cavitation erosion of 316 L SS, the semi-conductive property of passive films on 316 L SS containing different concentrations of Mo were studied by Mott-Schottky plot. Based on Mott-Schottky results and semiconductor physics, a physical model was proposed to explain the effect mechanism of Mo on cavitation erosion of 316 L SS. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Microstructure and Mechanical Properties of 316L Stainless Steel Filling Friction Stir-Welded Joints

    NASA Astrophysics Data System (ADS)

    Zhou, L.; Nakata, K.; Tsumura, T.; Fujii, H.; Ikeuchi, K.; Michishita, Y.; Fujiya, Y.; Morimoto, M.

    2014-10-01

    Keyhole left at 316L stainless steel friction stir welding/friction stir processing seam was repaired by filling friction stir welding (FFSW). Both metallurgical and mechanical bonding characteristics were obtained by the combined plastic deformation and flow between the consumable filling tool and the wall of the keyhole. Two ways based on the original conical and modified spherical keyholes, together with corresponding filling tools and process parameters were investigated. Microstructure and mechanical properties of 316L stainless steel FFSW joints were evaluated. The results showed that void defects existed at the bottom of the refilled original conical keyhole, while excellent bonding interface was obtained on the refilled modified spherical keyhole. The FFSW joint with defect-free interface obtained on the modified spherical keyhole fractured at the base metal side during the tensile test due to microstructural refinement and hardness increase in the refilled keyhole. Moreover, no σ phase but few Cr carbides were formed in the refilled zone, which would not result in obvious corrosion resistance degradation of 316L stainless steel.

  7. Corrosion behavior of 2205 duplex stainless steel.

    PubMed

    Platt, J A; Guzman, A; Zuccari, A; Thornburg, D W; Rhodes, B F; Oshida, Y; Moore, B K

    1997-07-01

    The corrosion of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material. Both stainless steels were subjected to electrochemical and immersion (crevice) corrosion tests in 37 degrees C, 0.9 wt% sodium chloride solution. Electrochemical testing indicates that 2205 has a longer passivation range than 316L. The corrosion rate of 2205 was 0.416 MPY (milli-inch per year), whereas 316L exhibited 0.647 MPY. When 2205 was coupled to 316L with equal surface area ratio, the corrosion rate of 2205 reduced to 0.260 MPY, indicating that 316L stainless steel behaved like a sacrificial anode. When 316L is coupled with NiTi, TMA, or stainless steel arch wire and was subjected to the immersion corrosion test, it was found that 316L suffered from crevice corrosion. On the other hand, 2205 stainless steel did not show any localized crevice corrosion, although the surface of 2205 was covered with corrosion products, formed when coupled to NiTi and stainless steel wires. This study indicates that considering corrosion resistance, 2205 duplex stainless steel is an improved alternative to 316L for orthodontic bracket fabrication when used in conjunction with titanium, its alloys, or stainless steel arch wires.

  8. Tensile Property of ANSI 304 Stainless Steel Weldments Subjected to Cavitation Erosion Based on Treatment of Laser Shock Processing.

    PubMed

    Zhang, Lei; Liu, Yue-Hua; Luo, Kai-Yu; Zhang, Yong-Kang; Zhao, Yong; Huang, Jian-Yun; Wu, Xu-Dong; Zhou, Chuang

    2018-05-16

    Tensile property was one important index of mechanical properties of ANSI 304 stainless steel laser weldments subjected to cavitation erosion (CE). Laser shock processing (LSP) was utilized to strengthen the CE resistance, and the tensile property and fracture morphology were analyzed through three replicated experiment times. Results showed tensile process of treated weldments was composed of elastic deformation, plastic deformation, and fracture. The elastic limit, elastic modulus, elongation, area reduction, and ultimate tensile strength of tensile sample after CE were higher in view of LSP. In the fracture surface, the fiber zone, radiation zone and shear lip zone were generated, and those were more obvious through LSP. The number and size of pores in the fracture surface were smaller, and the fracture surface was smoother and more uniform. The dimples were elongated along the unified direction due to effects of LSP, and the elongated direction was in agreement with the crack propagation direction. Their distribution and shape were uniform with deeper depth. It could be reflected that the tensile property was improved by LSP and the CE resistance was also enhanced.

  9. Tensile Property of ANSI 304 Stainless Steel Weldments Subjected to Cavitation Erosion Based on Treatment of Laser Shock Processing

    PubMed Central

    Zhang, Lei; Liu, Yue-Hua; Luo, Kai-Yu; Zhang, Yong-Kang; Zhao, Yong; Huang, Jian-Yun; Wu, Xu-Dong; Zhou, Chuang

    2018-01-01

    Tensile property was one important index of mechanical properties of ANSI 304 stainless steel laser weldments subjected to cavitation erosion (CE). Laser shock processing (LSP) was utilized to strengthen the CE resistance, and the tensile property and fracture morphology were analyzed through three replicated experiment times. Results showed tensile process of treated weldments was composed of elastic deformation, plastic deformation, and fracture. The elastic limit, elastic modulus, elongation, area reduction, and ultimate tensile strength of tensile sample after CE were higher in view of LSP. In the fracture surface, the fiber zone, radiation zone and shear lip zone were generated, and those were more obvious through LSP. The number and size of pores in the fracture surface were smaller, and the fracture surface was smoother and more uniform. The dimples were elongated along the unified direction due to effects of LSP, and the elongated direction was in agreement with the crack propagation direction. Their distribution and shape were uniform with deeper depth. It could be reflected that the tensile property was improved by LSP and the CE resistance was also enhanced. PMID:29772661

  10. Effect of strain wave shape on low-cycle fatigue crack propagation of SUS 304 stainless steel at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Okazaki, Masakazu; Hattori, Ichiro; Shiraiwa, Fujio; Koizumi, Takashi

    1983-08-01

    Effect of strain wave shape on strain-controlled low-cycle fatigue crack propagation of SUS 304 stainless steel was investigated at 600 and 700 °C. It was found that the rate of crack propagation in a cycle-dependent region was successfully correlated with the range of cyclic J-integral, Δ Jf, regardless of the strain wave shape, frequency, and test temperature. It was also shown that the rate of crack propagation gradually increased from cycle-dependent curve to time-dependent one with decreasing frequency and slow-fast strain wave shape, and that one of the factors governing the rate of crack propagation in such a region was the ratio of the range of creep J-integral to that of total J-integral, Δ J c/Δ JT. Based on the results thus obtained, an interaction damage rule proposed semi-empirically was interpreted, with regard to crack propagation. Furthermore, fatigue crack initiation mechanism in slow-fast strain wave shape was studied, and it was shown that grain boundary sliding took an important role in it.

  11. Electrochemical study on the corrosion resistance of plasma nanocoated 316L stainless steel in albumin- and lysozyme-containing electrolytes

    PubMed Central

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

    2017-01-01

    The physiological corrosion resistance of plasma nanocoated 316L stainless steel was studied in protein-containing electrolytes using electrochemical methods. Plasma nanocoatings with thicknesses of 20–30 nm were deposited onto 316L stainless steel coupons in a glow discharge of trimethylsilane (TMS) or its mixture with oxygen gas under various gas ratios. The surface chemistries of the plasma nanocoatings were characterized using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Corrosion properties of the plasma nanocoated 316L stainless steel coupons were assessed using potentiodynamic polarization, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) in phosphate-buffered saline (PBS) electrolytes that contain bovine serum albumin (BSA) or lysozyme. It was found that BSA adsorption on the plasma nanocoated 316L coupons was heavily favored. BSA adsorption on the plasma nanocoating surfaces could block charge-transfer reactions between the electrolyte and 316L substrate, and thus stabilize the 316L substrates from further corrosion. In contrast, lysozyme adsorption on the plasma nanocoated specimens was not as pronounced and mildly influenced the corrosion properties of the plasma nanocoated 316L stainless steel. PMID:29422723

  12. Transition joints between Zircaloy-2 and stainless steel by diffusion bonding

    NASA Astrophysics Data System (ADS)

    Bhanumurthy, K.; Krishnan, J.; Kale, G. B.; Banerjee, S.

    1994-11-01

    The diffusion bonding between Zircaloy-2 and stainless steel (AISI 304L) using niobium, nickel and copper as intermediate layers has been investigated in the temperature range of 750 to 900°C. Bonding was carried out in a vacuum hot press, under compressive loading. Electron probe microanalysis and metallographic analysis showed a good metallurgical compatibility and also indicated the absence of discontunities, micropores and intermetallic compounds at various interfaces. The bond strength of the diffusion bonded assembly was found to be about 400 MPa for the couples bonded at 870°C for 2 h. The dimple structure on the fractured surface is indicative of the ductile mode of failure of the bonded assembly.

  13. Cost and Performance Report: Introduction and Validation of Chromium-Free Consumables for Welding Stainless Steels. Version 2

    DTIC Science & Technology

    2015-04-01

    hexavalent chromium in the welding fume of stainless steel . Welds of both Cr-free consumables met the performance objectives of 70,000 pounds per square...hexavalent chromium (Cr(VI)) in the welding fume of stainless steel . This project was developed in two stages: laboratory demonstration and field...consumables they are designed to replace. The measured Cr(VI) in the fume of the SMAW electrode when welding Type 304 stainless steel is virtually zero

  14. The Synergistic Effect of Proteins and Reactive Oxygen Species on Electrochemical Behaviour of 316L Stainless Steel for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Simionescu, N.; Benea, L.; Dumitrascu, V. M.

    2018-06-01

    The stainless steels, especially 316L type is the most used metallic biomaterials for biomedical applications due to their good biocompatibility, low price, excellent corrosion resistance, availability, easy processing and high strength. Due to these favorable properties 316L stainless steel has become the most attractive biomaterial for dental implants, stents and orthopedic implants. However an implant material in the human body is exposed to an action effect of other molecules, including proteins (such as albumin) and reactive oxygen species (such as hydrogen peroxide - H2O2 ) produced by bacteria and immune cells. In the literature there are few studies to follow the effect of proteins and reactive oxygen species on 316L stainless steel used as implant material and are still unclear. The degree of corrosion resistance is the first criterion in the use of a metallic biomaterial in the oral or body environment. The aim of this research work is to investigate the influence of proteins (albumin) and reactive oxygen species (H2O2 ) in combination, taking into account the synergistic effect of these two factors on 316L stainless steel. Albumin is present in the body near implants and reactive oxygen species could appear in inflammatory processes as well. The study shows that the presence of albumin and reactive species influences the corrosion resistance of 316L stainless steel in biological solutions. In this research work the corrosion behavior of 316L stainless steel is analyzed by electrochemical methods such as: open circuit potential (OCP), Electrochemical Impedance Spectroscopy (EIS). It was found that, the electrochemical results are in a good agreement with micro photographs taken before and after corrosion assays. The albumin and reactive oxygen species have influence on 316L stainless steel behavior.

  15. Deep drawing of 304 L Steel Sheet using Vegetable oils as Forming Lubricants

    NASA Astrophysics Data System (ADS)

    Shashidhara, Y. M.; Jayaram, S. R.

    2012-12-01

    The study involves the evaluation of deep drawing process using two non edible oils, Pongam (Pongammia pinnata) and Jatropha (Jatropha carcass) as metal forming lubricants. Experiments are conducted on 304L steel sheets under the raw and modified oils with suitable punch and die on a hydraulic press of 200 ton capacity. The punch load, draw-in-length and wall thickness distribution for deep drawn cups are observed. The drawn cups are scanned using laser scanning technique and 3D models are generated using modeling package. The wall thickness profiles of cups at different sections (or height) are measured using CAD package. Among the two raw oils, the drawn cups under Jatropha oil, have uniform wall thickness profile compared to Pongam oil. Uneven flow of material and cup rupturing is observed under methyl esters of Pongam and Jatropha oil lubricated conditions. However, the results are observed under epoxidised Jatropha oil with uniform metal flow and wall thicknesses compared to mineral and other versions of vegetable oils.

  16. Evaluation of Distortion in Welding Unions of 304 Stainless Steel with Elliptic Trajectory Using a Welding Robot

    NASA Astrophysics Data System (ADS)

    Carrasco-González, L. A.; Hurtado-Delgado, E.; Reyes-Valdés, F. A.

    The aim of this investigation is to evaluate the distortions generated in welding unions of stainless steel 304 by effect of the welding temperature and the microestructural changes. The joint design is a 100 × 100 mm steel plate of 3 mm thickness. The plate was joined to a tube of 50 mm diameter and 2 mm thickness, which has a defined angular cut; therefore, the trajectory followed by the seam has an elliptic form. Temperature data acquisition was developed by type K thermocouples, placed in pairs at 0°, 90°, 180° and 270° along the welding trajectory and connected to a data acquisition device yo obtain the measures to generate time-temperature plots. The welding process was executed by a KUKA ®; KR16 welding robot with an integrated GMAW (Gas metal arc welding) process where the input parameters of voltage, wire feed and travel speed are set to constant. The distortion of the work piece was measured using a laser scanning technique that generates a point cloud with the VXelements TM software for comparison between the pre and post-weld condition. Microstructural evaluation was performed on transversal sections of the seam, at the mentioned angles for correlation.

  17. Cryogenic piping material selection for the Component Test Facility (CTF)

    NASA Technical Reports Server (NTRS)

    St. Cyr, William W.

    1991-01-01

    The anticipated high cost of the 8500 psi cryogenic and 15,000 psi gas piping systems used in the CTF at NASA's John C. Stennis Space Center led to the consideration of high-strength materials for these piping systems. Based on years of satisfactory service using austenitic stainless steels in cryogenic applications, particularly for hydrogen service, consideration was limited to the austenitic stainless steels. Attention was focused on alternatives to the 304/304L grades of stainless steel traditionally used in these applications. This paper discusses the various considerations that resulted in the decision to continue using 304/304L for the cryogenic piping and the selection of the nitrogen-strengthened 21Cr-6Ni-9Mn alloy (UNS S21903) for the high-pressure gas systems at the CTF.

  18. Reduction-oxidation Enabled Glass-ceramics to Stainless Steel Bonding Part I: screening of doping oxidants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dai, Steve Xunhu

    Lithium silicate-based glass-ceramics with high coefficients of thermal expansion, designed to form matched hermetic seals in 304L stainless steel housing, show little evidence of interfacial chemical bonding, despite extensive inter-diffusion at the glass-ceramic-stainless steel (GC-SS) interface. A series of glass-ceramic compositions modified with a variety of oxidants, AgO, FeO, NiO, PbO, SnO, CuO, CoO, MoO 3 and WO 3, are examined for the feasibility of forming bonding oxides through reduction-oxidation (redox) at the GC-SS interface. The oxidants were selected according to their Gibbs free energy to allow for oxidation of Cr/Mn/Si from stainless steel, and yet to prevent a reductionmore » of P2O5 in the glass-ceramic where the P 2O 5 is to form Li 3PO 4 nuclei for growth of high expansion crystalline SiO 2 phases. Other than the CuO and CoO modified glass-ceramics, bonding from interfacial redox reactions were not achieved in the modified glass-ceramics, either because of poor wetting on the stainless steel or a reduction of the oxidants at the surface of glass-ceramic specimens rather than the GC-SS interface.« less

  19. Microstructure Refinement and Mechanical Properties of 304 Stainless Steel by Repetitive Thermomechanical Processing

    NASA Astrophysics Data System (ADS)

    Al-Fadhalah, Khaled; Aleem, Muhammad

    2018-04-01

    Repetitive thermomechanical processing (TMP) was applied for evaluating the effect of strain-induced α'-martensite transformation and reversion annealing on microstructure refinement and mechanical properties of 304 austenitic stainless steel. The first TMP scheme consisted of four cycles of tensile deformation to strain of 0.4, while the second TMP scheme applied two cycles of tensile straining to 0.6. For both schemes, tensile tests were conducted at 173 K (- 100 °C) followed by 5-minute annealing at 1073 K (800 °C). The volume fraction of α'-martensite in deformed samples increased with increasing cycles, reaching a maximum of 98 vol pct. Examination of annealed microstructure by electron backscattered diffraction indicated that increasing strain and/or number of cycles resulted in stronger reversion to austenite with finer grain size of 1 μm. Yet, increasing strain reduced the formation of Σ3 boundaries. The annealing textures generally show reversion of α'-martensite texture components to the austenite texture of brass and copper orientations. The increase in strain and/or number of cycles resulted in stronger intensity of copper orientation, accompanied by the formation of recrystallization texture components of Goss, cube, and rotated cube. The reduction in grain size with increasing cycles caused an increase in yield strength. It also resulted in an increase in strain hardening rate during deformation due to the increase in the formation of α'-martensite. The increase in strain hardening rate occurred in two consecutive stages, marked as stages II and III. The strain hardening in stage II is due to the formation of α'-martensite from either austenite or ɛ-martensite, while the stage-III strain hardening is attributed to the necessity to break the α'-martensite-banded structure for forming block-type martensite at high strains.

  20. Effect of Low-Temperature Sensitization on the Corrosion Behavior of AISI Type 304L SS Weld Metal in Simulated Groundwater

    NASA Astrophysics Data System (ADS)

    Suresh, Girija; Nandakumar, T.; Viswanath, A.

    2018-04-01

    The manuscript presents the investigations carried out on the effect of low-temperature sensitization (LTS) of 304L SS weld metal on its corrosion behavior in simulated groundwater, for its application as a canister material for long-term storage of nuclear vitrified high-level waste in geological repositories. AISI type 304L SS weld pad was fabricated by multipass gas tungsten arc welding process using 308L SS filler wire. The as-welded specimens were subsequently subjected to carbide nucleation and further to LTS at 500 °C for 11 days to simulate a temperature of 300 °C for 100-year life of the canister in geological repositories. Delta ferrite (δ-ferrite) content of the 304L SS weld metal substantially decreased on carbide nucleation treatment and further only a marginal decrease occurred on LTS treatment. The microstructure of the as-welded consisted of δ-ferrite as a minor phase distributed in austenite matrix. The δ-ferrite appeared fragmented in the carbide-nucleated and LTS-treated weld metal. The degree of sensitization measured by double-loop electrochemical potentokinetic reactivation method indicated an increase in carbide nucleation treatment when compared to the as-welded specimens, and further increase occurred on LTS treatment. Potentiodynamic anodic polarization investigations in simulated groundwater indicated a substantial decrease in the localized corrosion resistance of the carbide-nucleated and LTS 304L SS weld metals, when compared to the as-welded specimens. Post-experimental micrographs indicated pitting as the primary mode of attack in the as-welded, while pitting and intergranular corrosion (IGC) occurred in the carbide-nucleated weld metal. LTS-treated weld metal predominantly underwent IGC attack. The decrease in the localized corrosion resistance of the weld metal after LTS treatment was found to have a direct correlation with the degree of sensitization and the weld microstructure. The results are detailed in the manuscript.

  1. Effect of Low-Temperature Sensitization on the Corrosion Behavior of AISI Type 304L SS Weld Metal in Simulated Groundwater

    NASA Astrophysics Data System (ADS)

    Suresh, Girija; Nandakumar, T.; Viswanath, A.

    2018-05-01

    The manuscript presents the investigations carried out on the effect of low-temperature sensitization (LTS) of 304L SS weld metal on its corrosion behavior in simulated groundwater, for its application as a canister material for long-term storage of nuclear vitrified high-level waste in geological repositories. AISI type 304L SS weld pad was fabricated by multipass gas tungsten arc welding process using 308L SS filler wire. The as-welded specimens were subsequently subjected to carbide nucleation and further to LTS at 500 °C for 11 days to simulate a temperature of 300 °C for 100-year life of the canister in geological repositories. Delta ferrite ( δ-ferrite) content of the 304L SS weld metal substantially decreased on carbide nucleation treatment and further only a marginal decrease occurred on LTS treatment. The microstructure of the as-welded consisted of δ-ferrite as a minor phase distributed in austenite matrix. The δ-ferrite appeared fragmented in the carbide-nucleated and LTS-treated weld metal. The degree of sensitization measured by double-loop electrochemical potentokinetic reactivation method indicated an increase in carbide nucleation treatment when compared to the as-welded specimens, and further increase occurred on LTS treatment. Potentiodynamic anodic polarization investigations in simulated groundwater indicated a substantial decrease in the localized corrosion resistance of the carbide-nucleated and LTS 304L SS weld metals, when compared to the as-welded specimens. Post-experimental micrographs indicated pitting as the primary mode of attack in the as-welded, while pitting and intergranular corrosion (IGC) occurred in the carbide-nucleated weld metal. LTS-treated weld metal predominantly underwent IGC attack. The decrease in the localized corrosion resistance of the weld metal after LTS treatment was found to have a direct correlation with the degree of sensitization and the weld microstructure. The results are detailed in the manuscript.

  2. Influence of the field humiture environment on the mechanical properties of 316L stainless steel repaired with Fe314

    NASA Astrophysics Data System (ADS)

    Zhang, Lianzhong; Li, Dichen; Yan, Shenping; Xie, Ruidong; Qu, Hongliang

    2018-04-01

    The mechanical properties of 316L stainless steel repaired with Fe314 under different temperatures and humidities without inert gas protection were studied. Results indicated favorable compatibility between Fe314 and 316L stainless steel. The average yield strength, tensile strength, and sectional contraction percentage were higher in repaired samples than in 316L stainless steel, whereas the elongation rate was slightly lower. The different conditions of humiture environment on the repair sample exerted minimal influence on tensile and yield strengths. The Fe314 cladding layer was mainly composed of equiaxed grains and mixed with randomly oriented columnar crystal and tiny pores or impurities in the tissue. Results indicated that the hardness value of Fe314 cladding layer under different humiture environments ranged within 419-451.1 HV0.2. The field humiture environment also showed minimal impact on the average hardness of Fe314 cladding layers. Furthermore, 316L stainless steel can be repaired through laser cladding by using Fe314 powder without inert gas protection under different temperatures and humidity environments.

  3. The Use of Austenitic Stainless Steel versus Monel (Ni-Cu) Alloy in Pressurized Gaseous Oxygen (GOX) Life Support Systems.

    DTIC Science & Technology

    1985-03-01

    Carbon Steel AISI 1025 2. AISI 4140 3. Ductile Iron 4. 304 Stainless Steel 5. 17-4 PH Stainless Steel 6. 410 Stainless Steel 7. Lead Babbit 8. Tin Babbit...9. Inconel 718 i0. Aluminum 1100 30 6- AISI 4140 steel, all the results were negative (no ignitions). The single exception was with a sample of 4140 ...rates for austenitic stainless steel ( AISI 316), Monel (63% Ni - 34% Cu) and carbon steel (AMS 5050) tubing in this environment. 12 - 14-660 A 7

  4. Comparative study of pulsed Nd:YAG laser welding of AISI 304 and AISI 316 stainless steels

    NASA Astrophysics Data System (ADS)

    Kumar, Nikhil; Mukherjee, Manidipto; Bandyopadhyay, Asish

    2017-02-01

    Laser welding is a potentially useful technique for joining two pieces of similar or dissimilar materials with high precision. In the present work, comparative studies on laser welding of similar metal of AISI 304SS and AISI 316SS have been conducted forming butt joints. A robotic control 600 W pulsed Nd:YAG laser source has been used for welding purpose. The effects of laser power, scanning speed and pulse width on the ultimate tensile strength and weld width have been investigated using the empirical models developed by RSM. The results of ANOVA indicate that the developed models predict the responses adequately within the limits of input parameters. 3-D response surface and contour plots have been developed to find out the combined effects of input parameters on responses. Furthermore, microstructural analysis as well as hardness and tensile behavior of the selected weld of 304SS and 316SS have been carried out to understand the metallurgical and mechanical behavior of the weld. The selection criteria are based on the maximum and minimum strength achieved by the respective weld. It has been observed that the current pulsation, base metal composition and variation in heat input have significant influence on controlling the microstructural constituents (i.e. phase fraction, grain size etc.). The result suggests that the low energy input pulsation generally produce fine grain structure and improved mechanical properties than the high energy input pulsation irrespective of base material composition. However, among the base materials, 304SS depict better microstructural and mechanical properties than the 316SS for a given parametric condition. Finally, desirability function analysis has been applied for multi-objective optimization for maximization of ultimate tensile strength and minimization of weld width simultaneously. Confirmatory tests have been conducted at optimum parametric conditions to validate the optimization techniques.

  5. 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.

  6. Mechanisms-based viscoplasticity: Theoretical approach and experimental validation for steel 304L

    PubMed Central

    Zubelewicz, Aleksander; Oliferuk, Wiera

    2016-01-01

    We propose a mechanisms-based viscoplasticity approach for metals and alloys. First, we derive a stochastic model for thermally-activated motion of dislocations and, then, introduce power-law flow rules. The overall plastic deformation includes local plastic slip events taken with an appropriate weight assigned to each angle of the plane misorientation from the direction of maximum shear stress. As deformation progresses, the material experiences successive reorganizations of the slip systems. The microstructural evolution causes that a portion of energy expended on plastic deformation is dissipated and the rest is stored in the defect structures. We show that the reorganizations are stable in a homogeneously deformed material. The concept is tested for steel 304L, where we reproduce experimentally obtained stress-strain responses, we construct the Frost-Ashby deformation map and predict the rate of the energy storage. The storage is assessed in terms of synchronized measurements of temperature and displacement distributions on the specimen surface during tensile loading. PMID:27026209

  7. Selection of Wire Electrical Discharge Machining Process Parameters on Stainless Steel AISI Grade-304 using Design of Experiments Approach

    NASA Astrophysics Data System (ADS)

    Lingadurai, K.; Nagasivamuni, B.; Muthu Kamatchi, M.; Palavesam, J.

    2012-06-01

    Wire electrical discharge machining (WEDM) is a specialized thermal machining process capable of accurately machining parts of hard materials with complex shapes. Parts having sharp edges that pose difficulties to be machined by the main stream machining processes can be easily machined by WEDM process. Design of Experiments approach (DOE) has been reported in this work for stainless steel AISI grade-304 which is used in cryogenic vessels, evaporators, hospital surgical equipment, marine equipment, fasteners, nuclear vessels, feed water tubing, valves, refrigeration equipment, etc., is machined by WEDM with brass wire electrode. The DOE method is used to formulate the experimental layout, to analyze the effect of each parameter on the machining characteristics, and to predict the optimal choice for each WEDM parameter such as voltage, pulse ON, pulse OFF and wire feed. It is found that these parameters have a significant influence on machining characteristic such as metal removal rate (MRR), kerf width and surface roughness (SR). The analysis of the DOE reveals that, in general the pulse ON time significantly affects the kerf width and the wire feed rate affects SR, while, the input voltage mainly affects the MRR.

  8. An assessment of ultra fine grained 316L stainless steel for implant applications.

    PubMed

    Muley, Sachin Vijay; Vidvans, Amey N; Chaudhari, Gajanan P; Udainiya, Sumit

    2016-01-01

    Ultra fine-grained metals obtained by severe plastic deformation exhibit higher specific strength that is useful for many applications and show promise for use as body implants. This work studied the microstructural evolution, mechanical and sliding wear behavior and corrosion behavior of 316L stainless steel warm multi axially forged at 600°C. Microstructural evolution studied using electron backscatter diffraction technique and transmission electron microscopy confirmed the formation of ultra fine-grained structure. Average grain size reduced from 30μm to 0.86μm after nine strain steps. A combination of Hall-Petch strengthening and strain hardening increased the hardness. Improved sliding wear resistance is attributed to a transition from micro cutting to wedge-forming mode of abrasive wear. Load-bearing orthopedic implants often fail from pitting initiated corrosion fatigue. Potentiodynamic tests, cyclic polarization, and FeCl3 immersion tests revealed enhanced pitting resistance of forged steel that is confirmed by Mott-Schottky analysis. This is ascribed to an increase in the grain boundary volume, and homogenization of pit inducing impurities and non-metallic phases due to severe deformation, which influenced the passive film properties. These model studies on 316L steel demonstrate that severely deformed ultra fine-grained metals have potential to deliver improved implant performance. This model study on 316L steel demonstrates that severely deformed ultra fine-grained (UFG) metals have potential to deliver improved load-bearing implant performance. It is as interesting as is unclear as to how such severely deformed UFG material behaves electrochemically in the corrosive body fluids. This work is on studying the inter-relationship between structure, and mechanical, wear, and corrosion behavior of warm multiaxially forged (MAFed) UFG 316L stainless steel. Warm MAF is a bulk processing method capable of yielding large volume of UFG material and is an easily

  9. Self-ion emulation of high dose neutron irradiated microstructure in stainless steels

    NASA Astrophysics Data System (ADS)

    Jiao, Z.; Michalicka, J.; Was, G. S.

    2018-04-01

    Solution-annealed 304L stainless steel (SS) was irradiated to 130 dpa at 380 °C, and to 15 dpa at 500 °C and 600 °C, and cold-worked 316 SS (CW 316 SS) was irradiated to 130 dpa at 380 °C using 5 MeV Fe++/Ni++ to produce microstructures and radiation-induced segregation (RIS) for comparison with that from neutron irradiation at 320 °C to 46 dpa in the BOR60 reactor. For the 304L SS alloy, self-ion irradiation at 380 °C produced a dislocation loop microstructure that was comparable to that by neutron irradiation. No voids were observed in either the 380 °C self-ion irradiation or the neutron irradiation conditions. Irradiation at 600 °C produced the best match to radiation-induced segregation of Cr and Ni with the neutron irradiation, consistent with the prediction of a large temperature shift by Mansur's invariant relations for RIS. For the CW 316 SS alloy irradiated to 130 dpa at 380 °C, both the irradiated microstructure (dislocation loops, precipitates and voids) and RIS reasonably matched the neutron-irradiated sample. The smaller temperature shift for RIS in CW 316 SS was likely due to the high sink (dislocation) density induced by the cold work. A single self-ion irradiation condition at a dose rate ∼1000× that in reactor does not match both dislocation loops and RIS in solution-annealed 304L SS. However, a single irradiation temperature produced a reasonable match with both the dislocation/precipitate microstructure and RIS in CW 316 SS, indicating that sink density is a critical factor in determining the temperature shift for self-ion irradiations.

  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. 77 FR 28568 - Grant of Authority for Subzone Status; North American Stainless, (Stainless Steel), Ghent, KY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-15

    ... Status; North American Stainless, (Stainless Steel), Ghent, KY Pursuant to its authority under the... application to the Board for authority to establish a special-purpose subzone at the stainless steel mill of... stainless steel at the facility of North American Stainless, located in Ghent, Kentucky (Subzone 29L), as...

  12. Study of the Corrosion Resistance of Austenitic Stainless Steels during Conversion of Waste to Biofuel

    PubMed Central

    Cabrini, Marina; Lorenzi, Sergio; Pastore, Tommaso; Pellegrini, Simone; Burattini, Mauro; Miglio, Roberta

    2017-01-01

    The paper deals with the corrosion behavior of stainless steels as candidate materials for biofuel production plants by liquefaction process of the sorted organic fraction of municipal solid waste. Corrosion tests were carried out on AISI 316L and AISI 304L stainless steels at 250 °C in a batch reactor during conversion of raw material to bio-oil (biofuel precursor), by exposing specimens either to water/oil phase or humid gas phase. General corrosion rate was measured by weight loss tests. The susceptibility to stress corrosion cracking was evaluated by means of U-bend specimens and slow stress rate tests at 10−6 or 10−5 s−1 strain rate. After tests, scanning electron microscope analysis was carried out to detect cracks and localized attacks. The results are discussed in relation with exposure conditions. They show very low corrosion rates strictly dependent upon time and temperature. No stress corrosion cracking was observed on U-bend specimens, under constant loading. Small cracks confined in the necking cone of specimens prove that stress corrosion cracking only occurred during slow strain rate tests at stresses exceeding the yield strength. PMID:28772682

  13. A Computational Study of Plastic Deformation in AISI 304 Induced by Surface Mechanical Attrition Treatment

    NASA Astrophysics Data System (ADS)

    Zhang, X. C.; Lu, J.; Shi, S. Q.

    2010-05-01

    As a technique of grain refinement process by plastic deformation, surface mechanical attrition treatment (SMAT) has been developed to be one of the most effective ways to optimize the mechanical properties of various materials including pure metals and alloys. SMAT can significantly reduce grain size into nanometer regime in the surface layer of bulk materials, providing tremendous opportunities for improving physical, chemical and mechanical properties of the materials. In this work, a computational modeling of the surface mechanical attrition treatment (SMAT) process is presented, in which Johnson-Cook plasticity model and the finite element method were employed to study the high strain rate, elastic-plastic dynamic process of ball impact on a metallic target. AISI 304 steel with low stacking fault energy was chosen as the target material. First, a random impact model was used to analyze the statistic characteristics of ball impact, and then the plastic deformation behavior and residual stress distribution in AISI 304 stainless steel during SMAT were studied. The simulation results show that the compressive residual stress and vertical deformation of the surface structures were directly affected by ball impact frequency, incident impact angle and ball diameter used in SMAT process.

  14. Tensile Fracture Behavior of 316L Austenitic Stainless Steel Manufactured by Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Cooper, A. J.; Brayshaw, W. J.; Sherry, A. H.

    2018-02-01

    Herein we investigate how the oxygen content in hot isostatically pressed (HIP'd) 316L stainless steel affects the mechanical properties and tensile fracture behavior. This work follows on from previous studies, which aimed to understand the effect of oxygen content on the Charpy impact toughness of HIP'd steel. We expand on the work by performing room-temperature tensile testing on different heats of 316L stainless steel, which contain different levels of interstitial elements (carbon and nitrogen) as well as oxygen in the bulk material. Throughout the work we repeat the experiments on conventionally forged 316L steel as a reference material. The analysis of the work indicates that oxygen does not contribute to a measureable solution strengthening mechanism, as is the case with carbon and nitrogen in austenitic stainless steels (Werner in Mater Sci Eng A 101:93-98, 1988). Neither does oxygen, in the form of oxide inclusions, contribute to precipitation hardening due to the size and spacing of particles. However, the oxide particles do influence fracture behavior; fractography of the failed tension test specimens indicates that the average ductile dimple size is related to the oxygen content in the bulk material, the results of which support an on-going hypothesis relating oxygen content in HIP'd steels to their fracture mechanisms by providing additional sites for the initiation of ductile damage in the form of voids.

  15. Local thermal expansions and lattice strains in Elinvar and stainless steel alloys

    NASA Astrophysics Data System (ADS)

    Yokoyama, Toshihiko; Koide, Akihiro; Uemura, Yohei

    2018-02-01

    Local thermal expansions and lattice strains in the Elinvar alloy Fe49.66Ni42.38Cr5.49Ti2.47 (Ni Span C) and the stainless steel SUS304 Fe71.98Ni9.07Cr18.09Mn0.86 (AISI304) were investigated by the temperature-dependent Cr, Fe, and Ni K -edge extended x-ray absorption fine-structure (EXAFS) measurements, combined with the path-integral effective classical potential Monte Carlo (PIECP MC) theoretical simulations. From the EXAFS analysis of the Elinvar alloy, the local thermal expansion around Fe is found to be considerably smaller than the ones around Ni and Cr. This observation can be understood simply because Fe in the Elinvar alloy exhibit an incomplete Invar-like effect. Moreover, in both the Elinvar and SUS304 alloys, the local thermal expansions and the lattice strains around Cr are found to be larger than those around Fe and Ni. From the PIECP MC simulations of both the alloys, the first-nearest neighbor Cr-Fe pair shows extraordinarily large thermal expansion, while the Cr-Cr pair exhibits quite small or even negative thermal expansion. These findings consequently indicate that the lattice strains in both the Elinvar and SUS304 alloys are concentrated predominantly on the Cr atoms. Although the role of Cr in stainless steel has been known to inhibit corrosion by the formation of surface chromium oxide, the present investigation may interestingly suggest that the Cr atoms in the bulk play a hidden new role of absorbing inevitable lattice strains in the alloys.

  16. Improved quantitative recovery of Listeria monocytogenes from stainless steel surfaces using a one-ply composite tissue.

    PubMed

    Vorst, Keith L; Todd, Ewen C D; Rysert, Elliot T

    2004-10-01

    Four sampling devices, a sterile environmental sponge (ES), a sterile cotton-tipped swab (CS), a sterile calcium alginate fiber-tipped swab (CAS), and a one-ply composite tissue (CT), were evaluated for quantitative recovery of Listeria monocytogenes from a food-grade stainless steel surface. Sterile 304-grade stainless steel plates (6 by 6 cm) were inoculated with approximately 106 CFU/cm2 L. monocytogenes strain Scott A and dried for 1 h. The ES and CT sampling devices were rehydrated in phosphate buffer solution. After plate swabbing, ES and CT were placed in 40 ml of phosphate buffer solution, stomached for 1 min and hand massaged for 30 s. Each CS and CAS device was rehydrated in 0.1% peptone before swabbing. After swabbing, CS and CAS were vortexed in 0.1% peptone for 1 min. Samples were spiral plated on modified Oxford agar with modified Oxford agar Rodac Contact plates used to recover any remaining cells from the stainless steel surface. Potential inhibition from CT was examined in both phosphate buffer solution and in a modified disc-diffusion assay. Recovery was 2.70, 1.34, and 0.62 log greater using CT compared with ES, CS, and CAS, respectively, with these differences statistically significant (P < 0.001) for ES and CT and for CAS, CS, and CT (P < 0.05). Rodac plates were typically overgrown following ES, positive after CS and CAS, and negative after CT sampling. CT was noninhibitory in both phosphate buffer solution and the modified disc-diffusion assay. Using scanning electron microscopy, Listeria cells were observed on stainless steel plates sampled with each sampling device except CT. The CT device, which is inexpensive and easy to use, represents a major improvement over other methods in quantifying L. monocytogenes on stainless steel surfaces and is likely applicable to enrichment of environmental samples.

  17. Physical properties and microstructure study of stainless steel 316L alloy fabricated by selective laser melting

    NASA Astrophysics Data System (ADS)

    Islam, Nurul Kamariah Md Saiful; Harun, Wan Sharuzi Wan; Ghani, Saiful Anwar Che; Omar, Mohd Asnawi; Ramli, Mohd Hazlen; Ismail, Muhammad Hussain

    2017-12-01

    Selective Laser Melting (SLM) demonstrates the 21st century's manufacturing infrastructure in which powdered raw material is melted by a high energy focused laser, and built up layer-by-layer until it forms three-dimensional metal parts. SLM process involves a variation of process parameters which affects the final material properties. 316L stainless steel compacts through the manipulation of building orientation and powder layer thickness parameters were manufactured by SLM. The effect of the manipulated parameters on the relative density and dimensional accuracy of the 316L stainless steel compacts, which were in the as-build condition, were experimented and analysed. The relationship between the microstructures and the physical properties of fabricated 316L stainless steel compacts was investigated in this study. The results revealed that 90° building orientation has higher relative density and dimensional accuracy than 0° building orientation. Building orientation was found to give more significant effect in terms of dimensional accuracy, and relative density of SLM compacts compare to build layer thickness. Nevertheless, the existence of large number and sizes of pores greatly influences the low performances of the density.

  18. Effect of polishing process on corrosion behavior of 308L stainless steel in high temperature water

    NASA Astrophysics Data System (ADS)

    Ma, Cheng; Han, En-Hou; Peng, Qunjia; Ke, Wei

    2018-06-01

    Effect of change in surface composition and roughness by different polishing processes on corrosion of 308L stainless steel in high temperature water was investigated. The investigation was conducted by comparing the corrosion behavior of electropolished specimens with that of the 40 nm-colloidal silica slurry polished specimens. The result revealed that the electropolished specimens had a higher corrosion rate than the colloidal silica slurry polished specimens, which was attributed to formation of an amount of chromium hydroxide and higher roughness of the electropolished surface. Moreover, the ferrite in 308L stainless steel was found to have a higher resistance to corrosion than the austenite matrix.

  19. Resistance of bacterial biofilms formed on stainless steel surface to disinfecting agent.

    PubMed

    Królasik, Joanna; Zakowska, Zofia; Krepska, Milena; Klimek, Leszek

    2010-01-01

    The natural ability of microorganisms for adhesion and biofilm formation on various surfaces is one of the factors causing the inefficiency of a disinfection agent, despite its proven activity in vitro. The aim of the study was to determine the effectiveness of disinfecting substances on bacterial biofilms formed on stainless steel surface. A universally applied disinfecting agent was used in the tests. Bacterial strains: Listeria innocua, Pseudomonas putida, Micrococcus luteus, Staphylococcus hominis strains, were isolated from food contact surfaces, after a cleaning and disinfection process. The disinfecting agent was a commercially available acid specimen based on hydrogen peroxide and peroxyacetic acid, the substance that was designed for food industry usage. Model tests were carried out on biofilm formed on stainless steel (type 304, no 4 finish). Biofilms were recorded by electron scanning microscope. The disinfecting agent in usable concentration, 0.5% and during 10 minutes was ineffective for biofilms. The reduction of cells in biofilms was only 1-2 logarithmic cycles. The use of the agent in higher concentration--1% for 30 minutes caused reduction of cell number by around 5 logarithmic cycles only in the case of one microorganism, M. luteus. For other types: L. innocua, P. putida, S. hominis, the requirements placed on disinfecting agents were not fulfilled. The results of experiments proved that bacterial biofilms are resistant to the disinfectant applied in its operational parameters. Disinfecting effectiveness was achieved after twofold increase of the agent's concentration.

  20. 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.

  1. Effects of the cryogenic cooling on the fatigue strength of the AISI 304 stainless steel ground components

    NASA Astrophysics Data System (ADS)

    Ben Fredj, Nabil; Sidhom, Habib

    2006-06-01

    For environmental considerations, the substitution of the conventionally used oil-based grinding fluids has nowadays become strongly recommended. Although several alternatives have been proposed, cryogenic cooling by liquid nitrogen is the non-polluting coolant that has been given relatively more attention because of its very low temperature. In this investigation, in order to contribute to developing this promising cooling mode, its beneficial effects on the ground surface integrity of the AISI 304 stainless steel and their consequences on the fatigue lifetime are explored. Results of this investigation show that grinding under cryogenic cooling mode generates surfaces with lower roughness, less defects, higher work hardening and less tensile residual stresses than those obtained on surfaces ground under oil-based grinding fluid. These surface enhancements result into substantial improvements in the fatigue behaviour of components ground under this cooling mode. An increasing rate of almost 15% of the endurance limit at 2 × 10 6 cycles could be realized. SEM analyses of the fatigue fracture surfaces have shown that the fatigue cracks observed on the specimens ground under cryogenic cooling are shorter (i.e., 30-50 μm) than those generated under oil-based cooling mode (i.e., 150-200 μm). The realized improvements in the surface integrity and in the fatigue behaviour are thought to be related to the reduction of the grinding zone temperature observed under cryogenic cooling, as no significant differences between the grinding force components for both cooling modes have been observed.

  2. Indium oxide thin film as potential photoanodes for corrosion protection of stainless steel under visible light

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Yan; Yu, Jianqiang, E-mail: jianqyu@qdu.edu.cn; Sun, Kai

    Graphical abstract: If the conduction band potential of In{sub 2}O{sub 3} is more negative than the corrosion potential of stainless steel, photo-induced electrons will be transferred from In{sub 2}O{sub 3} to the steel, thus shifting the potential of the steel into a corrosion immunity region and preventing the steel from the corrosion. - Highlights: • Indium oxide performed novel application under visible light. • Indium oxide by sol–gel method behaved better photoelectrochemical properties. • Electrons were transferred to stainless steel from indium oxide once light on. - Abstract: This paper reports the photoelectrochemical cathodic protection of 304 stainless steel bymore » In{sub 2}O{sub 3} thin-film under visible-light. The films were fabricated with In{sub 2}O{sub 3} powders, synthesized by both sol–gel (In{sub 2}O{sub 3}-sg) and solid-state (In{sub 2}O{sub 3}-ss) processes. The photo-induced open circuit potential and the photo-to-current efficiency measurements suggested that In{sub 2}O{sub 3} could be a promising candidate material for photoelectrochemical cathodic protection of metallic alloys under visible light. Moreover, the polarization curve experimental results indicated that In{sub 2}O{sub 3}-sg thin-film can mitigate the corrosion potential of 304 stainless steel to much more negative values with a higher photocurrent density than the In{sub 2}O{sub 3}-ss film under visible-light illumination. All the results demonstrated that the In{sub 2}O{sub 3}-sg thin-film provides a better photoelectrochemical cathodic protection for 304 stainless steel than In{sub 2}O{sub 3}-ss thin-film under visible-light illumination. The higher photoelectrochemical efficiency is possibly due to the uniform thin films produced with the smaller particle size of In{sub 2}O{sub 3}-sg, which facilitates the transfer of the photo-induced electrons from bulk to the surface and suppresses the charge recombination of the electrons and holes.« less

  3. Modulation of dry tribological property of stainless steel by femtosecond laser surface texturing

    NASA Astrophysics Data System (ADS)

    Wang, Zhuo; Zhao, Quanzhong; Wang, Chengwei; Zhang, Yang

    2015-06-01

    We reported on the modification of tribological properties of stainless steel by femtosecond laser surface microstructuring. Regular arranged micro-grooved textures with different spacing were produced on the AISI 304L steel surfaces by an 800-nm femtosecond laser. The tribological properties of smooth surface and textured surface were investigated by carrying out reciprocating ball-on-flat tests against Al2O3 ceramic balls under dry friction. Results show that the spacing of micro-grooves had a significant impact on friction coefficient of textured surfaces. Furthermore, the wear behaviors of smooth and textured surface were also investigated. Femtosecond laser surface texturing had a marked potential for modulating friction and wear properties if the micro-grooves were distributed in an appropriate manner.

  4. Materials selection for kraft batch digesters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wensley, A.; Moskal, M.; Wilton, W.

    1997-08-01

    Several candidate materials were evaluated by corrosion testing in autoclaves containing white and black liquors for batch digesters. The relationship between corrosion rate and corrosion potential was determined for ASTM SA516-Grade 70 carbon steel, UNS S30403 (Type 304L) austenitic stainless steel, UNS S31803 (2205) and UNS S32550 (2605) duplex stainless steels, and two stainless steel weld overlays, applied by the GMAW (gas metal arc welding) and SAW (submerged arc welding) processes. The tests revealed that SA516-Grade 70 carbon steel and type 304L stainless steel can experience high rates of corrosion. For the duplex stainless steels and weld overlays, corrosion resistancemore » improved with chromium content. A chromium content of at least 25% was found to be necessary for good corrosion resistance.« less

  5. Étude par diffraction des rayons X de la nitruration plasma d'un acier 304L Influence sur l'oxydation à 1000 ^{circ}C

    NASA Astrophysics Data System (ADS)

    Marot, L.; Buscail, H.; Straboni, A.; Riffard, F.; Caudron, E.; Cueff, R.

    2002-07-01

    This work presents the influence of various nitridation parameters on the 304L steel oxidation at 1000 ^{circ}C, in air under atmospheric pressure. Nitridation temperatures were ranging between 300 ^{circ}C and 430 ^{circ}C with exposure times lasting from 2 to 8 hours. At 300 and 430 ^{circ}C, the nitridation treatment leads to the solid solution surface formation γ-N without any nitride formation. After oxidation at 1000 ^{circ}C of blank specimens, X ray diffraction reveals the FeCr2O4 spinel formation. This oxide does not act as a good diffusion barrier. With nitrogen treated specimens, the higher the nitridation temperature is and the longer the exposure time is, better is the oxidation behaviour at 1000 ^{circ}C. We then observe that the Cr{1,3}Fe{0,7}O3 oxide is more present in the oxide sale from the very beginning of the oxidation test which is correlated to a final lower mass gain. Cette étude porte sur l'influence des paramètres de nitruration plasma sur l'oxydation de l'acier 304L à 1000 ^{circ}C, sous air, à la pression atmosphérique. Les températures employées lors de la nitruration ont été de 300 ^{circ}C et 430 ^{circ}C pour des durées de nitruration variant entre 2 et 8 heures. A 300 et 430 ^{circ}C, la nitruration conduit à la formation d'une solution solide γ-N en surface sans provoquer la formation de nitrures. Après oxydation à 1000 ^{circ}C du 304L non nitruré, la diffraction des rayons X révèle la formation d'une couche de type spinelle FeCr2O4 qui ne semble pas jouer le rôle de barrière de diffusion. Pour les échantillons préalablement nitrurés, plus la température de nitruration est élevée et plus la durée du traitement est longue, meilleur est le comportement en oxydation. Nous observons alors l'oxyde Cr{1,3}Fe{0,7}O3 en proportion importante dès le début de l'oxydation et une prise de masse finale plus faible.

  6. 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.

  7. 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. Copyright 2003 Wiley Periodicals, Inc.

  8. Deformation localization and dislocation channel dynamics in neutron-irradiated austenitic stainless steels

    DOE PAGES

    Gussev, Maxim N.; Field, Kevin G.; Busby, Jeremy T.

    2015-02-24

    We investigated dynamics of deformation localization and dislocation channel formation in situ in a neutron irradiated AISI 304 austenitic stainless steel and a model 304-based austenitic alloy by combining several analytical techniques including optic microscopy and laser confocal microscopy, scanning electron microscopy, electron backscatter diffraction and transmission electron microscopy. Channel formation was observed at 70% of the formal tensile yield stress for both alloys. It was shown that triple junction points do not always serve as a source of dislocation channels; at stress levels below the yield stress, channels often formed near the middle of the grain boundary. For amore » single grain, the role of elastic stiffness value (Young modulus) in the channel formation was analyzed; it was shown that in the irradiated 304 steels the initial channels appeared in soft grains with a high Schmid factor located near stiff grains with high elastic stiffness. Moreover, the spatial organization of channels in a single grain was analyzed; it was shown that secondary channels operating in the same slip plane as primary channels often appeared at the middle or at one third of the way between primary channels. The twinning nature of dislocation channels was analyzed for grains of different orientation using TEM. Finally, it was shown that in the AISI 304 steel, channels were twin-free in grains oriented close to [001] and [101] of standard unit triangle; [111]-grains and grains oriented close to Schmid factor maximum contained deformation twins.« less

  9. Parylene coatings on stainless steel 316L surface for medical applications--mechanical and protective properties.

    PubMed

    Cieślik, Monika; Kot, Marcin; Reczyński, Witold; Engvall, Klas; Rakowski, Wiesław; Kotarba, Andrzej

    2012-01-01

    The mechanical and protective properties of parylene N and C coatings (2-20 μm) on stainless steel 316L implant materials were investigated. The coatings were characterized by scanning electron and confocal microscopes, microindentation and scratch tests, whereas their protective properties were evaluated in terms of quenching metal ion release from stainless steel to simulated body fluid (Hanks solution). The obtained results revealed that for parylene C coatings, the critical load for initial cracks is 3-5 times higher and the total metal ions release is reduced 3 times more efficiently compared to parylene N. It was thus concluded that parylene C exhibits superior mechanical and protective properties for application as a micrometer coating material for stainless steel implants. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Effect of boron addition on injection molded 316L stainless steel: mechanical, corrosion properties and in vitro bioactivity.

    PubMed

    Bayraktaroglu, Esra; Gulsoy, H Ozkan; Gulsoy, Nagihan; Er, Ozay; Kilic, Hasan

    2012-01-01

    The research was investigated the effect of boron additions on sintering characteristics, mechanical, corrosion properties and biocompatibility of injection molded austenitic grade 316L stainless steel. Addition of boron is promoted to get high density of sintered 316L stainless steels. The amount of boron plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders have been used with the elemental NiB 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 temperature. The debinded samples were sintered at different temperature for 60 min. Mechanical property, microstructural characterization and electrochemical property of the sintered samples were performed using tensile testing, hardness, optical, scanning electron microscopy and electrochemical corrosion experiments. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. Results of study showed that sintered 316L and 316L with NiB addition samples exhibited high mechanical and corrosion properties in a physiological environment. Especially, 316L with NiB addition can be used in some bioapplications.

  11. 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.

  12. Simultaneously enhanced strength and ductility for 3D-printed stainless steel 316L by selective laser melting

    NASA Astrophysics Data System (ADS)

    Sun, Zhongji; Tan, Xipeng; Tor, Shu Beng; Chua, Chee Kai

    2018-04-01

    Laser-based powder-bed fusion additive manufacturing or three-dimensional printing technology has gained tremendous attention due to its controllable, digital, and automated manufacturing process, which can afford a refined microstructure and superior strength. However, it is a major challenge to additively manufacture metal parts with satisfactory ductility and toughness. Here we report a novel selective laser melting process to simultaneously enhance the strength and ductility of stainless steel 316L by in-process engineering its microstructure into a <011> crystallographic texture. We find that the tensile strength and ductility of SLM-built stainless steel 316L samples could be enhanced by 16% and 40% respectively, with the engineered <011> textured microstructure compared to the common <001> textured microstructure. This is because the favorable nano-twinning mechanism was significantly more activated in the <011> textured stainless steel 316L samples during plastic deformation. In addition, kinetic simulations were performed to unveil the relationship between the melt pool geometry and crystallographic texture. The new additive manufacturing strategy of engineering the crystallographic texture can be applied to other metals and alloys with twinning-induced plasticity. This work paves the way to additively manufacture metal parts with high strength and high ductility.

  13. Effect of welding structure and δ-ferrite on fatigue properties for TIG welded austenitic stainless steels at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Yuri, Tetsumi; Ogata, Toshio; Saito, Masahiro; Hirayama, Yoshiaki

    2000-04-01

    High-cycle and low-cycle fatigue properties of base and weld metals for SUS304L and SUS316L and the effects of welding structure and δ-ferrite on fatigue properties were investigated at cryogenic temperatures in order to evaluate the long-life reliability of the structural materials to be used in liquid hydrogen supertankers and storage tanks and to develop a welding process for these applications. The S-N curves of the base and weld metals shifted towards higher levels, i.e., the longer life side, with decreasing test temperatures. High-cycle fatigue tests demonstrated the ratios of fatigue strength at 10 6 cycles to tensile strength of the weld metals to be 0.35-0.7, falling below those of base metals with decreasing test temperatures. Fatigue crack initiation sites in SUS304L weld metals were mostly at blowholes with diameters of 200-700 μm, and those of SUS316L weld metals were at weld pass interface boundaries. Low-cycle fatigue tests revealed the fatigue lives of the weld metals to be somewhat lower than those of the base metals. Although δ-ferrite reduces the toughness of austenitic stainless steels at cryogenic temperatures, the effects of δ-ferrite on high-cycle and low-cycle fatigue properties are not clear or significant.

  14. Photocathodic Protection of 304 Stainless Steel by Bi2S3/TiO2 Nanotube Films Under Visible Light

    NASA Astrophysics Data System (ADS)

    Li, Hong; Wang, Xiutong; Wei, Qinyi; Hou, Baorong

    2017-01-01

    We report the preparation of TiO2 nanotubes coupled with a narrow bandgap semiconductor, i.e., Bi2S3, to improve the photocathodic protection property of TiO2 for metals under visible light. Bi2S3/TiO2 nanotube films were successfully synthesized using the successive ionic layer adsorption and reaction (SILAR) method. The morphology and structure of the composite films were studied by scanning electron microscopy and X-ray diffraction, respectively. UV-visible diffuse reflectance spectra were recorded to analyze the optical absorption property of the composite films. In addition, the influence of Bi2S3 deposition cycles on the photoelectrochemical and photocathodic protection properties of the composite films was also studied. Results revealed that the heterostructure comprised crystalline anatase TiO2 and orthorhombic Bi2S3 and exhibited a high visible light response. The photocurrent density of Bi2S3/TiO2 was significantly higher than that of pure TiO2 under visible light. The sensitization of Bi2S3 enhanced the separation efficiency of the photogenerated charges and photocathodic protection properties of TiO2. The Bi2S3/TiO2 nanotubes prepared by SILAR deposition with 20 cycles exhibited the optimal photogenerated cathodic protection performance on the 304 stainless steel under visible light.

  15. Photocathodic Protection of 304 Stainless Steel by Bi2S3/TiO2 Nanotube Films Under Visible Light.

    PubMed

    Li, Hong; Wang, Xiutong; Wei, Qinyi; Hou, Baorong

    2017-12-01

    We report the preparation of TiO 2 nanotubes coupled with a narrow bandgap semiconductor, i.e., Bi 2 S 3 , to improve the photocathodic protection property of TiO 2 for metals under visible light. Bi 2 S 3 /TiO 2 nanotube films were successfully synthesized using the successive ionic layer adsorption and reaction (SILAR) method. The morphology and structure of the composite films were studied by scanning electron microscopy and X-ray diffraction, respectively. UV-visible diffuse reflectance spectra were recorded to analyze the optical absorption property of the composite films. In addition, the influence of Bi 2 S 3 deposition cycles on the photoelectrochemical and photocathodic protection properties of the composite films was also studied. Results revealed that the heterostructure comprised crystalline anatase TiO 2 and orthorhombic Bi 2 S 3 and exhibited a high visible light response. The photocurrent density of Bi 2 S 3 /TiO 2 was significantly higher than that of pure TiO 2 under visible light. The sensitization of Bi 2 S 3 enhanced the separation efficiency of the photogenerated charges and photocathodic protection properties of TiO 2 . The Bi 2 S 3 /TiO 2 nanotubes prepared by SILAR deposition with 20 cycles exhibited the optimal photogenerated cathodic protection performance on the 304 stainless steel under visible light.

  16. Analysis of surface integrity in machining of AISI 304 stainless steel under various cooling and cutting conditions

    NASA Astrophysics Data System (ADS)

    Klocke, F.; Döbbeler, B.; Lung, S.; Seelbach, T.; Jawahir, I. S.

    2018-05-01

    Recent studies have shown that machining under specific cooling and cutting conditions can be used to induce a nanocrystalline surface layer in the workspiece. This layer has beneficial properties, such as improved fatigue strength, wear resistance and tribological behavior. In machining, a promising approach for achieving grain refinement in the surface layer is the application of cryogenic cooling. The aim is to use the last step of the machining operation to induce the desired surface quality to save time-consuming and expensive post machining surface treatments. The material used in this study was AISI 304 stainless steel. This austenitic steel suffers from low yield strength that limits its technological applications. In this paper, liquid nitrogen (LN2) as cryogenic coolant, as well as minimum quantity lubrication (MQL), was applied and investigated. As a reference, conventional flood cooling was examined. Besides the cooling conditions, the feed rate was varied in four steps. A large rounded cutting edge radius and finishing cutting parameters were chosen to increase the mechanical load on the machined surface. The surface integrity was evaluated at both, the microstructural and the topographical levels. After turning experiments, a detailed analysis of the microstructure was carried out including the imaging of the surface layer and hardness measurements at varying depths within the machined layer. Along with microstructural investigations, different topological aspects, e.g., the surface roughness, were analyzed. It was shown that the resulting microstructure strongly depends on the cooling condition. This study also shows that it was possible to increase the micro hardness in the top surface layer significantly.

  17. Development of nano/sub-micron grain structures in metastable austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Rajasekhara, Shreyas

    2007-12-01

    This dissertation is a part of a collaborative work between the University of Texas, Austin-Texas, the University of Oulu, Oulu-Finland, and Outokumpu Stainless Oy, Tornio-Finland, to develop commercial austenitic stainless steels with high strength and ductility. The idea behind this work involves cold-rolling a commercial metastable austenitic stainless steel - AISI 301LN stainless steel to produce strain-induced martensite, followed by an annealing treatment to generate nano/sub-micron grained austenite. AISI 301LN stainless steel sheets are cold-rolled to 63% reduction and subsequently annealed at 600°C, 700°C, 800°C, 900°C and 1000°C for 1, 10 and 100 seconds. The samples are analyzed by X-Ray diffraction, SQUID, transmission electron microscopy, and tensile testing to fundamentally understand the microstructural evolution, the mechanism for the martensite → austenite reversion, the formation of nano/sub-micron austenite grains, and the relationship between the microstructure and the strength obtained in this stainless steel. The results show that cold-rolled AISI 301LN stainless steel consist of dislocation-cell martensite, heavily deformed lath-martensite and austenite shear bands. Subsequent annealing at 600°C for short durations of 1 and 10 seconds leads to negligible martensite to austenite reversion. These 600°C samples exhibit a similar microstructure to the cold-rolled sample. However, for samples annealed at 600°C for 100 seconds and those annealed at higher temperatures (700°C, 800°C, 900°C and 1000°C) exhibit equiaxed austenitic grains of sizes 0.2mum-10mum and secondary phase precipitates. The microstructural analysis also reveals that the martensite → austenite reversion occurs via a diffusion-type reversion mechanism. In this regard, a generalized form of Avrami's equation is used to model the kinetics of martensite → austenite phase reversion. The results from the model agree reasonably well with the experiments. Furthermore

  18. 2017 Status report-Tritium aging studies on stainless steel: Effect of hydrogen, tritium and decay helium on the fracture-toughness properties of stem, cup and block forgings

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Morgan, Michael J.

    The materials of construction of tritium reservoirs are forged stainless steels. During service, the structural properties of the stainless steel change over time because of the diffusion of tritium into the reservoir wall and its radioactive decay to helium-3. This aging effect can cause cracks to initiate and grow which could result in a tritium leak or delayed failure of a tritium reservoir. Numerous factors affect the tendency for crack formation and propagation and are being investigated in this program. The goal of the research is to provide relevant fracture mechanics data that can be used by the design agenciesmore » in their assessments of tritium reservoir structural integrity. In this status report, new experimental results are presented on the effects of tritium and decay helium on the cracking properties of specimens taken from actual tritium reservoir forgings instead of the experimental forgings of past programs. The properties measured are more representative of actual reservoir properties because the microstructure of the specimens tested are more like that of the actual tritium reservoirs. The program was designed to measure the effects of material variables on tritium compatibility and includes two stainless steels (Type 304L and 316L stainless steel), multiple yield strengths (360-500 MPa), and multiple forging shapes (Stem, Cup, and Block).« less

  19. Evaluation of ion release, cytotoxicity, and platelet adhesion of electrochemical anodized 316 L stainless steel cardiovascular stents.

    PubMed

    Díaz, M; Sevilla, P; Galán, A M; Escolar, G; Engel, E; Gil, F J

    2008-11-01

    316L Stainless steel is one of the most used metallic material in orthopedical prosthesis, osteosinthesis plates, and cardiovascular stents. One of the main problems this material presents is the nickel and chromium release, specially the Ni ion release that provokes allergy in a high number of patients. Recently, experimental applications in vitro and in vivo seem to indicate that the thickness of the nature oxide of the stainless steel results in very strong reinforcement of the biological response and reduce the ion release due to the thicker surface oxide. It is possible to grow the natural chromium oxide layer by electrolytic method such anodization. In this study, two main anodization methods to grow chromium oxide on the 316L stainless steel have been evaluated. Nickel and Chromium ions release in human blood at 37 degrees C were detected at times of 1, 6, 11, and 15 days by means of atomic absorption in a graphite furnace (GAAF). Moreover, cytocompatibility tests were carried out. Perfusion experiments were performed to evaluate morphometrically platelet interaction with the material and to explore the potential thrombogenicity. The results showed a good cytocompatibility between the material and the osteoblast-like cells. However, these anodization methods released between 2 and 10 times more nickel and chromium than the original stainless steel, depending on the method used. Besides, anodized samples shown an increase of the percentage of surface covered by platelets. Consequently, the anodization methods studied do not improve the long-term behavior of the stainless steel for its application as cardiovascular stents.

  20. High temperature chlorosilane corrosion of iron and AISI 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Aller, Joshua Loren

    Chlorosilane gas streams are used at high temperatures (>500°C) throughout the semiconductor, polycrystalline silicon, and fumed silica industries, primarily as a way to refine, deposit, and produce silicon and silicon containing materials. The presence of both chlorine and silicon in chlorosilane species creates unique corrosion environments due to the ability of many metals to form both metal-chlorides and metal-silicides, and it is further complicated by the fact that many metal-chlorides are volatile at high-temperatures while metal-silicides are generally stable. To withstand the uniquely corrosive environments, expensive alloys are often utilized, which increases the cost of final products. This work focuses on the corrosion behavior of iron, the primary component of low-cost alloys, and AISI 316L, a common low-cost stainless steel, in environments representative of industrial processes. The experiments were conducted using a customized high temperature chlorosilane corrosion system that exposed samples to an atmospheric pressure, high temperature, chlorosilane environment with variable input amounts of hydrogen, silicon tetrachloride, and hydrogen chloride plus the option of embedding samples in silicon during the exposure. Pre and post exposure sample analysis including scanning electron microscopy, x-ray diffraction, energy dispersive x-ray spectroscopy, and gravimetric analysis showed the surface corrosion products varied depending on the time, temperature, and environment that the samples were exposed to. Most commonly, a volatile chloride product formed first, followed by a stratified metal silicide layer. The chlorine and silicon activities in the corrosion environment were changed independently and were found to significantly alter the corrosion behavior; a phenomenon supported by computational thermodynamic equilibrium simulations. It was found that in comparable environments, the stainless steel corroded significantly less than the pure iron. This

  1. Study on micro fabricated stainless steel surface to anti-biofouling using electrochemical fabrication

    NASA Astrophysics Data System (ADS)

    Hwang, Byeong Jun; Lee, Sung Ho

    2017-12-01

    Biofilm formed on the surface of the object by the microorganism resulting in fouling organisms. This has led to many problems in daily life, medicine, health and industrial community. In this study, we tried to prevent biofilm formation on the stainless steel (SS304) sheet surface with micro fabricated structure. After then forming the microscale colloid patterns on the surface of stainless steel by using an electrochemical etching forming a pattern by using a FeCl3 etching was further increase the surface roughness. Culturing the Pseudomonas aeruginosa on the stainless steel fabricated with a micro structure on the surface was observed a relationship between the surface roughness and the biological fouling of the micro structure. As a result, the stainless steel surface with a micro structure was confirmed to be the biological fouling occurs less. We expect to be able to solve the problems caused by biological fouling in various fields such as medicine, engineering, using this research.

  2. Linear Friction Welding of Dissimilar Materials 316L Stainless Steel to Zircaloy-4

    NASA Astrophysics Data System (ADS)

    Wanjara, P.; Naik, B. S.; Yang, Q.; Cao, X.; Gholipour, J.; Chen, D. L.

    2018-02-01

    In the nuclear industry, there are a number of applications where the transition of stainless steel to Zircaloy is of technological importance. However, due to the differences in their properties there are considerable challenges associated with developing a joining process that will sufficiently limit the heat input and welding time—so as to minimize the extent of interaction at the joint interface and the resulting formation of intermetallic compounds—but still render a functional metallurgical bond between these two alloys. As such, linear friction welding, a solid-state joining technology, was selected in the present study to assess the feasibility of welding 316L stainless steel to Zircaloy-4. The dissimilar alloy welds were examined to evaluate their microstructural characteristics, microhardness evolution across the joint interface, static tensile properties, and fatigue behavior. Microstructural observations revealed a central intermixed region and, on the Zircaloy-4 side, dynamically recrystallized and thermomechanically affected zones were present. By contrast, deformation on the 316L stainless steel side was limited. In the intermixed region a drastic change in the composition was observed along with a local increase in hardness, which was attributed to the presence of intermetallic compounds, such as FeZr3 and Cr2Zr. The average yield (316 MPa) and ultimate tensile (421 MPa) strengths met the minimum strength properties of Zircaloy-4, but the elongation was relatively low ( 2 pct). The tensile and fatigue fracture of the welds always occurred at the interface in the mode of partial cohesive failure.

  3. Enhanced cell adhesion on severe peened-plasma nitrided 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Jayalakshmi, M.; Bhat, Badekai Ramachandra; Bhat, K. Udaya

    2018-04-01

    Plasma nitriding is an effective technique to enhance the wear resistance of austenitic stainless steels. Recently, severe surface deformation techniques are extensively used prior to nitriding to enhance diffusion kinetics. In the present study, AISI 316L austenitic stainless steel is subjected to peening-nitriding duplex treatment and biocompatibility of treated surfaces is assessed through adhesion of the fibroblast cells. Three-fold increase in the surface microhardness is observed from the un-peened sample to the peened-nitrided sample; with severe peened sample showing intermediate hardness. Similar trend is observed in the number of the fibroblast cells attached to the sample surface. Spreading of some of the fibroblast cells is observed on the sample subjected to duplex treatment; while the other two samples showed only the spindle shaped fibroblasts. Combined influence of surface nanocrystallization and presence of nitride layer is responsible for the improved biocompatibility.

  4. Passivation and electrochemical behavior of 316L stainless steel in chlorinated simulated concrete pore solution

    NASA Astrophysics Data System (ADS)

    Luo, Hong; Su, Huaizhi; Dong, Chaofang; Li, Xiaogang

    2017-04-01

    In this paper, the passivation and electrochemical behavior of 316L stainless steel in chlorinated simulated concrete pore solutions at different pH was evaluated by potentiodynamic measurements, electrochemical impedance spectroscopy. The composition of the passive film and surface morphology were investigated by X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and scanning electron microscopy, respectively. The results reveal that metastable pitting susceptibility, stable pitting corrosion, and composition of the passive film are influenced by pH value. After long time immersion, a bilayer structure passive film can be formed in this environment. The appearance of molybdates on the outermost surface layer, further enhancing the stability of the passive film. Moreover, the good pitting corrosion resistance of 316L stainless steel in simulated concrete pore solution without carbonated is mainly due to the presence of high Cr/Fe ratio and molybdates ions within the passive film.

  5. The influence of implanted yttrium on the cyclic oxidation behaviour of 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Riffard, F.; Buscail, H.; Caudron, E.; Cueff, R.; Issartel, C.; Perrier, S.

    2006-03-01

    High-temperature alloys are frequently used in power plants, gasification systems, petrochemical industry, combustion processes and in aerospace applications. Depending on the application, materials are subjected to corrosive atmospheres and thermal cycling. In the present work, thermal cycling was carried out in order to study the influence of implanted yttrium on the oxide scale adherence on 304 steel specimens oxidised in air at 1273 K. In situ X-ray diffraction indicates that the oxides formed at 1273 K are different on blank specimens compared to implanted specimens. Glancing angle XRD allows to analyse the oxide scale composition after cooling to room temperature. Experimental results show that yttrium implantation at a nominal dose of 10 17 ions cm -2 does not improve significantly the cyclic oxidation behaviour of the austenitic AISI 304 steel. However, it appears that yttrium implantation remarkably enhance the oxidation resistance during isothermal oxidation. It reduces the transient oxidation stage and the parabolic oxidation rate constant by one order of magnitude.

  6. Influence of hydrogen on the corrosion behavior of stainless steels in lithium

    NASA Astrophysics Data System (ADS)

    Shulga, A. V.

    2008-02-01

    Corrosion behavior of several stainless steels in lithium and lithium with 0.05%H has been examined. Corrosion tests were performed under static conditions at 600 and 700 °C in the austenitic stainless steel of the type AISI 304 containers. Intensive formation of σ-phase of the composition Fe 50Cr 43Mo 3Ni 4 on the surface of austenitic stainless steels of the type AISI 316 at 700 °C for 1000 h was established as a result of isothermal mass transfer. Addition of 0.05%H in the form of LiH to lithium resulted in an increase in the quantity of the σ-phase. After corrosion tests of ferritic/martensitic steel in lithium at 700 °C for 1000 h the formation of the γ-phase was observed. In Li + 0.05%H besides the γ-phase was also formed the σ-phase. The features of decarburization of investigated stainless steels were examined using the direct method of activation autoradiography on carbon. Addition of 0.05%H in lithium significantly decreased the carbon content in the decarburization zone of austenitic stainless steel Fe-18Cr-15Ni-0.15C-0.23B without a noticeable change in the thickness of the decarburization zone. Decarburization of ferritic/martensitic stainless steel was less than of austenitic stainless steel using the same corrosion tests.

  7. Welding of Vanadium, Tantalum, 304L and 21-6-9 Stainless Steels, and Titanium Alloys at Lawrence Livermore National Laboratory using a Fiber Delivered 2.2 kW Diode Pumped CW Nd:YAG Laser

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Palmer, T; Elmer, J; Pong, R

    This report summarizes the results of a series of laser welds made between 2003 and 2005 at Lawrence Livermore National Laboratory (LLNL). The results are a compilation of several, previously unpublished, internal LLNL reports covering the laser welding of vanadium, tantalum, 304L stainless steel, 21-6-9 (Nitronic 40) steel, and Ti-6Al-4V. All the welds were made using a Rofin Sinar DY-022 diode pumped continuous wave Nd:YAG laser. Welds are made at sharp focus on each material at various power levels and travel speeds in order to provide a baseline characterization of the performance of the laser welder. These power levels aremore » based on measurements of the output power of the laser system, as measured by a power meter placed at the end of the optics train. Based on these measurements, it appears that the system displays a loss of approximately 10% as the beam passes through the fiber optic cable and laser optics. Since the beam is delivered to the fixed laser optics through a fiber optic cable, the effects of fiber diameter are also briefly investigated. Because the system utilizes 1:1 focusing optics, the laser spot size at sharp focus generally corresponds to the diameter of the fiber with which the laser is delivered. Differences in the resulting weld penetration in the different materials system are prevalent, with the welds produced on the Nitronic 40 material displaying the highest depths (> 5 mm) and minimal porosity. A Primes focusing diagnostic has also been installed on this laser system and used to characterize the size and power density distribution of the beams as a function of both power and focus position. Further work is planned in which this focusing diagnostic will be used to better understand the effects of changes in beam properties on the resulting weld dimensions in these and other materials systems.« less

  8. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Optimization of cutting parameters in CNC turning of stainless steel 304 with TiAlN nano coated carbide cutting tool

    NASA Astrophysics Data System (ADS)

    Durga Prasada Rao, V.; Harsha, N.; Raghu Ram, N. S.; Navya Geethika, V.

    2018-02-01

    In this work, turning was performed to optimize the surface finish or roughness (Ra) of stainless steel 304 with uncoated and coated carbide tools under dry conditions. The carbide tools were coated with Titanium Aluminium Nitride (TiAlN) nano coating using Physical Vapour Deposition (PVD) method. The machining parameters, viz., cutting speed, depth of cut and feed rate which show major impact on Ra are considered during turning. The experiments are designed as per Taguchi orthogonal array and machining process is done accordingly. Then second-order regression equations have been developed on the basis of experimental results for Ra in terms of machining parameters used. Regarding the effect of machining parameters, an upward trend is observed in Ra with respect to feed rate, and as cutting speed increases the Ra value increased slightly due to chatter and vibrations. The adequacy of response variable (Ra) is tested by conducting additional experiments. The predicted Ra values are found to be a close match of their corresponding experimental values of uncoated and coated tools. The corresponding average % errors are found to be within the acceptable limits. Then the surface roughness equations of uncoated and coated tools are set as the objectives of optimization problem and are solved by using Differential Evolution (DE) algorithm. Also the tool lives of uncoated and coated tools are predicted by using Taylor’s tool life equation.

  10. Low-Temperature Aging Characteristics of Type 316L Stainless Steel Welds: Dependence on Solidification Mode

    NASA Astrophysics Data System (ADS)

    Abe, Hiroshi; Watanabe, Yutaka

    2008-06-01

    Thermal aging embrittlement of light water reactor (LWR) components made of stainless steel cast has been recognized as a potential degradation issue, and careful attention has been paid to it. Although welds of austenitic stainless steels have γ-δ duplex microstructure, which is similar to that of the stainless steel cast, examination of the thermal aging characteristics of the stainless steel welds is very limited. In this investigation, two types of type 316L stainless steel weld metal with different solidification modes were prepared using two kinds of filler metals having tailored Ni equivalent and Cr equivalent. Differences between the two weld metals in the morphology of microstructure, in the composition of δ-ferrite, and in hardening behaviors with isothermal aging at 335 °C have been investigated. The hardness of the ferrite phase has increased with aging time, while the hardness of austenite phase has stayed the same. The mottled aspect has been observed in δ-ferrite of aged samples by transmission electron microscopy (TEM) observation. These characteristics suggest that spinodal decomposition has occurred in δ-ferrite by aging at 335 °C. The age-hardening rate of δ-ferrite was faster for the primary austenite solidification mode (AF mode) sample than the primary ferrite solidification mode (FA mode) sample in the initial stage of the aging up to 2000 hours. It has been suggested that the solidification mode can affect the kinetics of spinodal decomposition.

  11. 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. © 2013.

  12. Temperature Effects on Stainless Steel 316L Corrosion in the Environment of Sulphuric Acid (H2SO4)

    NASA Astrophysics Data System (ADS)

    Ayu Arwati, I. G.; Herianto Majlan, Edy; Daud, Wan Ramli Wan; Shyuan, Loh Kee; Arifin, Khuzaimah Binti; Husaini, Teuku; Alfa, Sagir; Ashidiq, Fakhruddien

    2018-03-01

    In its application, metal is always in contact with its environment whether air, vapor, water, and other chemicals. During contact, chemical interactions emerge between metals and their respective environments such that the metal surface corrodes. This study aims to determine the corrosion rate of 316L stainless steel sulphuric acid environment (H2SO4) with weight loss and electrochemical methods. The corrosion rate (CR) is value of 316L stainless steel by weight loss method with sulfuric acid (H2SO4) with concentration of 0.5 M. The result obtained in conjunction with the increase of temperature the rate of erosion obtained appears to be larger, with a consecutive 3 hour the temperature of 50°C is 0.27 mg/cm2h, temperature 70°C 0.38 mg/cm2h, and temperature 90 °C 0.52 mg/cm2h. With the electrochemical method, the current value increases by using a C350 potentiostal tool. The higher the current, the longer the time the corrosion rate increases, where the current is at 90 °C with a 10-minute treatment time of 0.0014736 A. The 316L stainless steel in surface metal morphology is shown by using a Scanning Electron Microscope (SEM).

  13. Surface Conditioning of Cardiovascular 316L Stainless Steel Stents: a Review

    NASA Astrophysics Data System (ADS)

    Navarro, Lucila; Luna, Julio; Rintoul, Ignacio

    2017-07-01

    Cardiovascular disease is the leading cause of death worldwide and 90% of coronary interventions consists in stenting procedures. Most of the implanted stents are made of AISI 316L stainless steel (SS). Excellent mechanical properties, biocompatibility, corrosion resistance, workability and statistically demonstrated medical efficiency are the reasons for the preference of 316L SS over any other material for stent manufacture. However, patients receiving 316L SS bare stents are reported with 15-20% of restenosis probability. The decrease of the restenosis probability is the driving force for a number of strategies for surface conditioning of 316L SS stents. This review reports the latest advances in coating, passivation and the generation of controlled topographies as strategies for increasing the corrosion resistance and reducing the ion release and restenosis probability on 316L SS stents. Undoubtedly, the future of technique is related to the elimination of interfaces with abrupt change of properties, the elimination of molecules and any other phase somehow linked to the metal substrate. And leaving the physical, chemical and topographical smart modification of the outer part of the 316L SS stent for enhancing the biocompatiblization with endothelial tissues.

  14. In situ evaluation of supersolidus liquid phase sintering phenomena of stainless steel 316L: Densification and distortion

    NASA Astrophysics Data System (ADS)

    Bollina, Ravi

    Supersolidus liquid phase sintering (SLPS) is a variant of liquid phase sintering. In SLPS, prealloyed powders are heated between the solidus and liquidus temperature of the alloy. This thesis focuses on processing of stainless steel 316L via SLPS by adding boron. Various amounts of boron were added to study the effect of boron on densification and distortion. The sintering window for water atomized 316L with 0.2% boron ranges from 1430 to 1435°C and 1225 to 1245°C for water atomized 316L with 0.8% boron. The rate of change of liquid content with temperature dVL/dt decreases from 1.5%/°C to 0.1%/°C for in increase in boron content from 0 to 0.8%, giving a wider range and better control during sintering. Further; effect of boron on mechanical properties and corrosion properties was researched. It was possible to achieve tensile strength of 476+/-21 MPa and an yield strength of 250+/-5 MPa with an elongation of 15+/-2 % in water atomized 316L with 0.8% boron. Fracture analysis indicates the presence of a brittle boride phase along the grain boundary causing intergranular fracture resulting in poor ductility. The crux of this thesis discusses the evolution of apparent viscosity and its relation to the microstructure. Beam bending viscometry was successfully used to evaluate the in situ apparent viscosity evolution of water atomized 316L with 0.2 and 0.8% boron additions. The apparent viscosity drops from 174 GPa.s at 1200°C to 4 GPa.s at 1275°C with increasing fractional liquid coverage in the water atomized 316L with 0.8% boron. The apparent viscosity calculated from bending beam and was used as an input into a finite element model (FEM) derived from constitutive equations and gives an excellent, fit between simulation and experiment. The densification behavior of boron doped stainless steel was modelled using Master Sintering Curve (MSC) (based on work of sintering) for the first time. It is proven that MSC can be used to identify change in densification rate

  15. 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.

  16. 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.

  17. 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. © 2014 Wiley Periodicals, Inc.

  18. Effect of current and travel speed variation of TIG welding on microstructure and hardness of stainless steel SS 316L

    NASA Astrophysics Data System (ADS)

    Jatimurti, Wikan; Abdillah, Fakhri Aulia; Kurniawan, Budi Agung; Rochiem, Rochman

    2018-04-01

    One of the stainless steel types that widely used in industry is SS 316L, which is austenitic stainless steel. One of the welding methods to join stainless steel is Tungsten Inert Gas (TIG), which can affect its morphology, microstructure, strength, hardness, and even lead to cracks in the weld area due to the given heat input. This research has a purpose of analyzing the relationship between microstructure and hardness value of SS 316L stainless steel after TIG welding with the variation of current and travel speed. The macro observation shows a distinct difference in the weld metal and base metal area, and the weld form is not symmetrical. The metallographic test shows the phases that formed in the specimen are austenite and ferrite, which scattered in three welding areas. The hardness test showed that the highest hardness value found in the variation of travel speed 12 cm/min with current 100 A. Welding process and variation were given do not cause any defects in the microstructure, such as carbide precipitation and sigma phase, means that it does not affect the hardness and corrosion resistance of all welded specimen.

  19. Role of beta 1-4 linked polymers in the biofilm structure of marine Pseudomonas sp. CE-2 on 304 stainless steel coupons.

    PubMed

    Jain, Anand; Bhosle, Narayan B

    2008-01-01

    Pseudomonas sp CE-2 cells attach and form biofilms on 304-stainless steel (SS) coupons. A series of experiments were carried out in order to understand the role of exopolysaccharides (EPS) in the formation and maintenance of CE-2 biofilms on SS coupons. The biofilm density and EPS concentration increased over the period of incubation and the highest values for both were recorded after 72 h. Calcofluor and the lectin concanavalin A (Con A) showed a positive interaction with 72-h old biofilms, indicating the presence of beta 1-4 linked polymers, and alpha-d-glucose and alpha-d-mannose in the biofilm matrix of CE-2. When the CE-2 cells were grown in the presence of calcofluor (200 microg ml(-1)), biofilm formation was significantly reduced (approximately 85%). Conversely, the lectins Con A or WGA did not influence the CE-2 biofilms on the SS coupons. Furthermore, treatment with cellulase, an enzyme specific for the degradation of beta 1-4 linked polymers, removed substantial amounts of CE-2 biofilm from SS coupons. These results strongly suggest the involvement of beta 1-4 linked polymers in the formation and maintenance of Pseudomonas sp. CE-2 biofilms on SS coupons.

  20. Calorimetric Investigation of Thermal Stability of 304H Cu (Fe-17.7Cr-9.3Ni-2.95Cu-0.91Mn-0.58Nb-0.24Si-0.1C-0.12N-Wt Pct) Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Tripathy, Haraprasanna; Subramanian, Raju; Hajra, Raj Narayan; Rai, Arun Kumar; Rengachari, Mythili; Saibaba, Saroja; Jayakumar, Tammana

    2016-12-01

    The sequence of phase instabilities that take place in a Fe-17.7Cr-9.3Ni-0.58Nb-2.95Cu-0.12N (wt pct) austenitic stainless steel (304H Cu grade) as a function of temperature has been investigated using dynamic calorimetry. The results obtained from this investigation are supplemented by Thermocalc-based equilibrium and Scheil-Gulliver nonequilibrium solidification simulation. The following phase transformation sequence is found upon slow cooling from liquid: LL + γ → L + γ + MX → γ + MX + δ → γ +MX + M23C6 → γ + MX + M23C6 + Cu. Under slow cooling, the solidification follows austenite + ferrite (AF) mode, which is in accordance with Thermocalc prediction and Scheil-Gulliver simulation. However, higher cooling rates result in skeletal δ-ferrite formation, due to increased segregation tendency of Nb and Cr to segregate to interdendritic liquid. The solidification mode is found to depend on combined Nb + Cu content. Experimental estimates of enthalpy change associated with melting and secondary phase precipitation are also obtained. In addition a semi-quantitative study on the dissolution kinetics of M23C6 type carbides has also been investigated. The standard solution treatment at 1413 K (1140 °C) is found to be adequate to dissolve both Cu and M23C6 into γ-austenite; but the complete dissolution of MX type carbonitrides occurs near the melting region.

  1. The Effect of Heat Treatments and Coatings on the Outgassing Rate of Stainless Steel Chambers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mamum, Md Abdullah A.; Elmustafa, Abdelmageed A,; Stutzman, Marcy L.

    The outgassing rates of four nominally identical 304L stainless steel vacuum chambers were measured to determine the effect of chamber coatings and heat treatments. One chamber was coated with titanium nitride (TiN) and one with amorphous silicon (a-Si) immediately following fabrication. One chamber remained uncoated throughout, and the last chamber was first tested without any coating, and then coated with a-Si following a series of heat treatments. The outgassing rate of each chamber was measured at room temperatures between 15 and 30 deg C following bakes at temperatures between 90 and 400 deg C. Measurements for bare steel showed amore » significant reduction in the outgassing rate by more than a factor of 20 after a 400 deg C heat treatment (3.5 x 10{sup 12} TorrL s{sup -1}cm{sup -2} prior to heat treatment, reduced to 1.7 x 10{ sup -13} TorrL s{sup -1}cm{sup -2} following heat treatment). The chambers that were coated with a-Si showed minimal change in outgassing rates with heat treatment, though an outgassing rate reduced by heat treatments prior to a-Si coating was successfully preserved throughout a series of bakes. The TiN coated chamber exhibited remarkably low outgassing rates, up to four orders of magnitude lower than the uncoated stainless steel. An evaluation of coating composition suggests the presence of elemental titanium which could provide pumping and lead to an artificially low outgassing rate. The outgassing results are discussed in terms of diffusion-limited versus recombination-limited processes.« less

  2. Dislocation evolution in 316 L stainless steel during multiaxial ratchetting deformation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dong Yawei; Kang Guozheng, E-mail: guozhengkang@yahoo.com.cn; Liu Yujie

    2012-03-15

    Dislocation patterns and their evolutions in 316 L stainless steel during the multiaxial ratchetting deformation were observed by transmission electron microscopy (TEM). The microscopic observations indicate that the dislocation evolution presented during the multiaxial ratchetting with four kinds of multiaxial loading paths is similar to that in the uniaxial case [G. Z. Kang et al., Mater Sci Eng A 527 (2010) 5952]. That is, dislocation networks and dislocation tangles are formed quickly by the multiple-slip and cross-slip of dislocation activated by applied multiaxial stress; and then polarized patterns such as dislocation walls and elongated incipient dislocation cells are formed atmore » the last stage of multiaxial ratchetting. The dislocation patterns evolve more quickly from the modes at low dislocation density to the ones at high density during the multiaxial ratchetting than that in the uniaxial case, and some traces of multiple-slip are observed in the multiaxial ones. The dislocation evolution during the multiaxial ratchetting deformation is summarized by comparing the observed dislocation patterns with those presented in the multiaxial strain-controlled and symmetrical stress-controlled cyclic tests. The multiaxial ratchetting of 316 L stainless steel can be microscopically and qualitatively explained by the observed evolution of dislocation patterns. - Highlights: Black-Right-Pointing-Pointer Dislocation patterns change from lines and nets to tangles, walls and cells. Black-Right-Pointing-Pointer Dislocation patterns evolve quicker in the multiaxial case. Black-Right-Pointing-Pointer Aligned dislocation arrays and some traces of multiple slips are observed. Black-Right-Pointing-Pointer Heterogeneous dislocation patterns result in the multiaxial ratchetting.« less

  3. Structural, mechanical, and magnetic properties of ferrite-austenite mixture in evaporated 304 stainless steel thin films

    NASA Astrophysics Data System (ADS)

    Merakeb, Noureddine; Messai, Amel; Djelloul, Abdelkader; Ayesh, Ahmad I.

    2015-11-01

    In this paper, we investigate the structure, composition, magnetic, and mechanical properties of stainless steel thin films formed by thermal evaporation technique. These thin films reveal novel structural and physical properties where they were found to consist of nanocrystals that are ~90 % body-centred cubic crystal structure which holds ferromagnetic properties (α-phase), and ~10 % face-centred cubic crystal structure which is paramagnetic at room temperature (γ-phase). The presence of the above phases was quantified by X-ray diffraction, transmission electron microscopy, and conversion electron Mössbauer spectroscopy. The magnetic properties were evaluated by a superconducting quantum interference device magnetometer, and they confirmed the dual-phase crystal structure of the stainless thin films, where the presence of γ-phase reduced the magnetization of the produced thin films. In addition, the fabricated stainless steel thin films did not contain micro-cracks, and they exhibit a tensile stress of about 1.7 GPa, hardness of 7.5 GPa, and elastic modulus of 104 GPa.

  4. Peptide-based biocoatings for corrosion protection of stainless steel biomaterial in a chloride solution.

    PubMed

    Muruve, Noah G G; Cheng, Y Frank; Feng, Yuanchao; Liu, Tao; Muruve, Daniel A; Hassett, Daniel J; Irvin, Randall T

    2016-11-01

    In this work, PEGylated D-amino acid K122-4 peptide (D-K122-4-PEG), derived from the type IV pilin of Pseudomonas aeruginosa, coated on 304 stainless steel was investigated for its corrosion resistant properties in a sodium chloride solution by various electrochemical measurements, surface characterization and molecular dynamics simulation. As a comparison, stainless steel electrodes coated with non-PEGylated D-amino acid retroinverso peptide (RI-K122-4) and D-amino acid K122-4 peptide (D-K122-4) were used as control variables during electrochemical tests. It was found that the D-K122-4-PEG coating is able to protect the stainless steel from corrosion in the solution. The RI-K122-4 coating shows corrosion resistant property and should be investigated further, while the D-K122-4 peptide coating, in contrast, shows little to no effect on corrosion. The morphological characterizations support the corrosion resistance of D-K122-4-PEG on stainless steel. The adsorption of D-K122-4 molecules occurs preferentially on Fe2O3, rather than Cr2O3, present on the stainless steel surface. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Cavitation erosion resistance of diamond-like carbon coating on stainless steel

    NASA Astrophysics Data System (ADS)

    Cheng, Feng; Jiang, Shuyun

    2014-02-01

    Two diamond-like carbon (DLC) coatings are prepared on stainless steel 304 by cathodic arc plasma deposition technology at different substrate bias voltages and arc currents (-200 V/80 A, labeled DLC-1, and -100 V/60 A, labeled DLC-2). Cavitation tests are performed by using a rotating-disk test rig to explore the cavitation erosion resistance of the DLC coating. The mass losses, surface morphologies, chemical compositions and the phase constituents of the specimens after cavitation tests are examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the DLC-2 coatings can elongate the incubation period of stainless steel, leading to an excellent cavitation erosion resistance as compared to the untreated stainless steel specimens. After duration of 100 h cavitation test, serious damaged surfaces and plenty of scratches can be observed on the surfaces of the stainless steel specimens, while only a few grooves and tiny pits are observed on the DLC-2 coatings. It is concluded that, decreasing micro defects and increasing adhesion can reduce the delamination of DLC coating, and the erosion continues in the stainless steel substrate after DLC coating failure, and the eroded surface of the substrate is subjected to the combined action from cavitation erosion and slurry erosion.

  6. Tritium Effects on Fracture Toughness of Stainless Steel Weldments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    MORGAN, MICHAEL; CHAPMAN, G. K.; TOSTEN, M. H.

    2005-05-12

    The effects of tritium on the fracture toughness properties of Type 304L and Type 21-6-9 stainless steel weldments were measured. Weldments were tritium-charged-and-aged and then tested in order to measure the effect of the increasing decay helium content on toughness. The results were compared to uncharged and hydrogen-charged samples. For unexposed weldments having 8-12 volume percent retained delta ferrite, fracture toughness was higher than base metal toughness. At higher levels of weld ferrite, the fracture toughness decreased to values below that of the base metal. Hydrogen-charged and tritium-charged weldments had lower toughness values than similarly charged base metals and toughnessmore » decreased further with increasing weld ferrite content. The effect of decay helium content was inconclusive because of tritium off-gassing losses during handling, storage and testing. Fracture modes were dominated by the dimpled rupture process in unexposed weldments. In hydrogen and tritium-exposed weldments, the fracture modes depended on the weld ferrite content. At high ferrite contents, hydrogen-induced transgranular fracture of the weld ferrite phase was observed.« less

  7. Corrosion and wear behaviors of boronized AISI 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Kayali, Yusuf; Büyüksaǧiş, Aysel; Yalçin, Yılmaz

    2013-09-01

    In this study, the effects of a boronizing treatment on the corrosion and wear behaviors of AISI 316L austenitic stainless steel (AISI 316L) were examined. The corrosion behavior of the boronized samples was studied via electrochemical methods in a simulation body fluid (SBF) and the wear behavior was examined using the ball-on-disk wear method. It was observed that the boride layer that formed on the AISI 316L surface had a flat and smooth morphology. Furthermore, X-ray diffraction analyses show that the boride layer contained FeB, Fe2B, CrB, Cr2B, NiB, and Ni2B phases. Boride layer thickness increased with an increasing boronizing temperature and time. The boronizing treatment also increased the surface hardness of the AISI 316L. Although there was no positive effect of the coating on the corrosion resistance in the SBF medium. Furthermore, a decrease in the friction coefficient was recorded for the boronized AISI 316L. As the boronizing temperature increased, the wear rate decreased in both dry and wet mediums. As a result, the boronizing treatment contributed positively to the wear resistance by increasing the surface hardness and by decreasing the friction coefficient of the AISI 316L.

  8. A SURVEY OF THE CORROSION OF MARTENSITIC AND FERRITIC STAINLESS STEELS IN PRESSURIZED WATER

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Beaver, R.J.; Leitten, C.F. Jr.

    1963-07-16

    >The corrosion resistance of mantensitic and ferritic austenitic stainless steels and carbon steels in pressurized water at 500 to 600 deg F is compared. Included are specific out-of-pile data for austenitic stainless steels, AISI types types 410, 420, 431, and 440C; the ferritic AISI types 430, 442, and 446; the precipitation-hardening type 17-4PH; and carbon steels, ASTM 212 A and B. Available corrosion results obtained under irradiation at exposures in the range of 7 x 10/sup 16/ to 3 x 10/sup 19/ nvt are also included for types 304, types of martensitic and ferritic stainless steels which were evaluated domore » not contain nickel. For application where it is desirable to minimize Co/sup 58/ activity produced from nickel, selection of a martensitic or ferritic stainless steel may be more appropriate than choosing the more popular nickel-bearing austenitic stainless steel or a fuel-element cladding material. Interpretation of the data indicates that, on the average, martensitic and ferritic stainless steels corrode more rapidly than austenitic alloys but more slowly than carbon and low-alloy steels. Under selected controlled water conditions or under irradiation, the corrosion of the nickel-free stainless steels appears to differ little from the austenitics. The corrosion of martensitic and ferritic stainless steels in pressurized-water systems therefore does not appear of such magnitude as to rule out development of these materials as the cladding fuel elements for specific applications. (auth)« less

  9. 76 FR 2708 - Porcelain-on-Steel Cooking Ware From Taiwan; Top-of-the-Stove Stainless Steel Cooking Ware From...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-14

    .... 701- TA-267 and 731-TA-304 (Third Review)] Porcelain-on-Steel Cooking Ware From Taiwan; Top-of-the-Stove Stainless Steel Cooking Ware From Korea AGENCY: United States International Trade Commission...-steel cooking ware from Taiwan and the antidumping and countervailing duty orders on imports of top-of...

  10. The effect of cyclic loading on the irradiation hardening of type 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Scholz, R.

    1997-01-01

    Strain controlled fatigue tests have been performed in torsion on annealed type 316L stainless steel irradiated with 19 MeV deuterons at 400°C for shear strain ranges between 0.95% and 1.4%. The irradiation hardening of the material was suppressed to a great extent for continuous cycling conditions in comparison to hold time tests.

  11. Improvement of the cavitation erosion resistance for Cr3Si film on stainless steel by double cathode glow discharge

    NASA Astrophysics Data System (ADS)

    Ding, Hongqin; Qiu, Yujiang

    2017-04-01

    In this study, sputter-deposited Cr3Si film was prepared by double cathode glow discharge (DCGD) technique onto 304 stainless steel. The phase constituents, surface microstructure and chemical compositions of the film were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After the DCGD process, the hardness of Cr3Si film was 26 GPa, about 10 times of the stainless steel, 2.5 GPa. The cavitation erosion resistance of Cr3Si film and stainless steel were investigated by using an ultrasonic vibration cavitation erosion system. After 30 hours of cavitation tests, the cumulative mass loss of Cr3Si film was only 60% of the stainless steel. Compared with the untreated stainless steel, the cavitation erosion resistance of Cr3Si film was improved. The cavitation mechanism of Cr3Si film is due to the delamination and spalling of local surface layer derived from its inherent brittleness.

  12. Pathfinder Atomic Power Plant Nozzle Galling Test, Final Report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None, None

    1961-12-29

    Galling tests of 304, 17-4PH, and chrome-plated 304 stainless-steel nozzles with 304 stainless-steel sleeves were conducted at Pathflnder reactor conditions of 480 deg F, 600 psig. A horizontal force was imposed on the sleeve with the nozzle inserted; and the nozzle was moved axially to determine galling tendencies. Galling was produced on both the 304 and 17-4PH stainless-steel nozzles. The chrome-plated 304-stainless-steel nozzles were cycled numerous times without galling. On the basis of these tests, chrome-plated 304-stainless- steel is the material selected for the Pathfinder boiler fuel-element nozzle.

  13. In-Pile Tests for IASCC Growth Behavior of Irradiated 316L Stainless Steel under Simulated BWR Condition in JMTR

    NASA Astrophysics Data System (ADS)

    Chimi, Yasuhiro; Kasahara, Shigeki; Ise, Hideo; Kawaguchi, Yoshihiko; Nakano, Junichi; Nishiyama, Yutaka

    The Japan Atomic Energy Agency (JAEA) has an in-pile irradiation test plan to evaluate in-situ effects of neutron/γ-ray irradiation on stress corrosion crack (SCC) growth of irradiated stainless steels using the Japan Materials Testing Reactor (JMTR). SCC growth rate and its dependence on electrochemical corrosion potential (ECP) are different between in-pile test and post irradiation examination (PIE). These differences are not fully understood because of a lack of in-pile data. This paper presents a systematic review on SCC growth data of irradiated stainless steels, an in-pile test plan for crack growth of irradiated SUS316L stainless steel under simulated BWR conditions in the JMTR, and the development of the in-pile test techniques.

  14. Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Farmer, J.C.; Van Konynenburg, R.A.; McCright, R.D.

    1988-04-01

    Three iron- to nickel-based austenitic alloys (Types 304L and 316L stainless steels and Alloy 825) are being considered as candidate materials for the fabrication of high-level radioactive-waste containers. Waste will include fuel assemblies from reactors as well as high-level waste in borosilicate glass forms, and will be sent to the prospective repository at Yucca Mountain, Nevada. The decay of radionuclides in the repository will result in the generation of substantial heat and in fluences of gamma radiation. Container materials may undergo any of several modes of degradation in this environment, including atmospheric oxidation; uniform aqueous phase corrosion; pitting; crevice corrosion;more » sensitization and intergranular stress corrosion cracking (IGSCC); and transgranular stress corrosion cracking (TGSCC). This report is an analysis of data relevant to the pitting, crevice corrosion, and stress corrosion cracking (SCC) of the three austenitic candidate alloys. The candidates are compared in terms of their susceptibilities to these forms of corrosion. Although all three candidates have demonstrated pitting and crevice corrosion in chloride-containing environments, Alloy 825 has the greatest resistance to these types of localized corrosion (LC); such resistance is important because pits can penetrate the metal and serve as crack initiation sites. Both Types 304L and 316L stainless steels are susceptible to SCC in acidic chloride media. In contrast, SCC has not been documented in Alloy 825 under comparable conditions. Gamma radiation has been found to enhance SCC in Types 304 and 304L stainless steels, but it has no detectable effect on the resistance of Alloy 825 to SCC. Furthermore, while the effects of microbiologically induced corrosion have been observed for 300-series stainless steels, nickel-based alloys such as Alloy 825 seem to be immune to such problems. 211 refs., 49 figs., 10 tabs.« less

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 extendingmore » 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.« less

  16. Characterization of corrosion scale formed on stainless steel delivery pipe for reclaimed water treatment.

    PubMed

    Cui, Yong; Liu, Shuming; Smith, Kate; Yu, Kanghua; Hu, Hongying; Jiang, Wei; Li, Yuhong

    2016-01-01

    To reveal corrosion behavior of stainless steel delivery pipe used in reclaimed water treatment, this research focused on the morphological, mineralogical and chemical characteristics of stainless steel corrosion scale and corroded passive film. Corrosion scale and coupon samples were taken from a type 304 pipe delivering reclaimed water to a clear well in service for more than 12 years. Stainless steel corrosion scales and four representative pipe coupons were investigated using mineralogy and material science research methods. The results showed corrosion scale was predominantly composed of goethite, lepidocrocite, hematite, magnetite, ferrous oxide, siderite, chrome green and chromite, the same as that of corroded pipe coupons. Hence, corrosion scale can be identified as podiform chromite deposit. The loss of chromium in passive film is a critical phenomenon when stainless steel passive film is damaged by localized corrosion. This may provide key insights toward improving a better comprehension of the formation of stainless steel corrosion scale and the process of localized corrosion. The localized corrosion behavior of stainless steel is directly connected with reclaimed water quality parameters such as residual chlorine, DO, Cl(-) and SO4(2-). In particular, when a certain amount of residual chlorine in reclaimed water is present as an oxidant, ferric iron is the main chemical state of iron minerals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Long-term stability of self-assembled monolayers on 316L stainless steel.

    PubMed

    Kaufmann, C R; Mani, G; Marton, D; Johnson, D M; Agrawal, C M

    2010-04-01

    316L stainless steel (316L SS) has been extensively used for making orthopedic, dental and cardiovascular implants. The use of phosphonic acid self-assembled monolayers (SAMs) on 316L SS has been previously explored for potential biomedical applications. In this study, we have investigated the long-term stability of methyl (-CH(3)) and carboxylic acid (-COOH)-terminated phosphonic acid SAMs on 316L under physiological conditions. The stability of SAMs on mechanically polished and electropolished 316L SS was also investigated as a part of this study. Well-ordered and uniform -CH(3)- and -COOH-terminated SAMs were coated on mechanically polished and electropolished 316L SS surfaces. The long-term stability of SAMs on 316L SS was investigated for up to 28 days in Tris-buffered saline (TBS) at 37 degrees C using x-ray photoelectron spectroscopy, atomic force microscopy and contact angle goniometry. A significant amount of phosphonic acid molecules was desorbed from the 316L SS surfaces within 1 to 7 days of TBS immersion followed by a slow desorption of molecules over the remaining days. The -COOH-terminated SAM was found to be more stable than the -CH(3)-terminated SAM on both mechanically and electropolished surfaces. No significant differences in the desorption behavior of SAMs were observed between mechanically and electropolished 316L SS surfaces.

  18. Reporting the Fatigue Life of 316L Stainless Steel Locking Compression Plate Implants: The Role of the Femoral and Tibial Biomechanics During the Gait.

    PubMed

    Rice, Devyn; Shaat, Mohamed

    2017-10-01

    In this study, the fatigue characteristics of femoral and tibial locking compression plate (LCP) implants are determined accounting for the knee biomechanics during the gait. A biomechanical model for the kinematics and kinetics of the knee joint during the complete gait cycle is proposed. The rotations of the femur, tibia, and patella about the knee joint during the gait are determined. Moreover, the patellar-tendon force (PT), quadriceps-tendon force (QT), the tibiofemoral joint force (TFJ), and the patellofemoral joint force (PFJ) through the standard gait cycle are obtained as functions of the body weight (BW). On the basis of the derived biomechanics of the knee joint, the fatigue factors of safety along with the fatigue life of 316L stainless steel femoral and tibial LCP implants are reported as functions of the BW and bone fracture location, for the first time. The reported results reveal that 316L stainless steel LCP implants for femoral surgeries are preferred for conditions in which the bone fracture is close to the knee joint and the BW is less than 80 kg. For tibial surgeries, 316L stainless steel LCP implants can be used for conditions in which the bone fracture is close to the knee joint and the BW is less than 100 kg. This study presents a critical guide for the determination of the fatigue characteristics of LCP implants. The obtained results reveal that the fatigue analyses should be performed on the basis of the body biomechanics to guarantee accurate designs of LCP implants for femoral and tibial orthopedic surgeries.

  19. Plasma Nitriding of AISI 304 Stainless Steel in Cathodic and Floating Electric Potential: Influence on Morphology, Chemical Characteristics and Tribological Behavior

    NASA Astrophysics Data System (ADS)

    Li, Yang; He, Yongyong; Wang, Wei; Mao, Junyuan; Zhang, Lei; Zhu, Yijie; Ye, Qianwen

    2018-03-01

    In direct current plasma nitriding (DCPN), the treated components are subjected to a high cathodic potential, which brings several inherent shortcomings, e.g., damage by arcing and the edging effect. In active screen plasma nitriding (ASPN) processes, the cathodic potential is applied to a metal screen that surrounds the workload, and the component to be treated is placed in a floating potential. Such an electrical configuration allows plasma to be formed on the metal screen surface rather than on the component surface; thus, the shortcomings of the DCPN are eliminated. In this work, the nitrided experiments were performed using a plasma nitriding unit. Two groups of samples were placed on the table in the cathodic and the floating potential, corresponding to the DCPN and ASPN, respectively. The floating samples and table were surrounded by a steel screen. The DCPN and ASPN of the AISI 304 stainless steels are investigated as a function of the electric potential. The samples were characterized using scanning electron microscopy with energy-dispersive x-ray spectroscopy, x-ray diffraction, atomic force microscopy and transmission electron microscope. Dry sliding ball-on-disk wear tests were conducted on the untreated substrate, DCPN and ASPN samples. The results reveal that all nitrided samples successfully produced similar nitrogen-supersaturated S phase layers on their surfaces. This finding also shows the strong impact of the electric potential of the nitriding process on the morphology, chemical characteristics, hardness and tribological behavior of the DCPN and ASPN samples.

  20. Effect of Bonding Time on Interfacial Reaction and Mechanical Properties of Diffusion-Bonded Joint Between Ti-6Al-4V and 304 Stainless Steel Using Nickel as an Intermediate Material

    NASA Astrophysics Data System (ADS)

    Thirunavukarasu, Gopinath; Kundu, Sukumar; Mishra, Brajendra; Chatterjee, Subrata

    2014-04-01

    In the current study, solid-state diffusion bonding between Ti-6Al-4V (TiA) and 304 stainless steel (SS) using pure nickel (Ni) of 200- μm thickness as an intermediate material was carried out in vacuum. Uniaxial compressive pressure and temperature were kept at 4 MPa and 1023 K (750 °C), respectively, and the bonding time was varied from 30 to 120 minutes in steps of 15 minutes. Scanning electron microscopy images, in backscattered electron mode, revealed the layerwise Ti-Ni-based intermetallics like either Ni3Ti or both Ni3Ti and NiTi at titanium alloy-nickel (TiA/Ni) interface, whereas nickel-stainless steel (Ni/SS) interface was free from intermetallic phases for all the joints. Chemical composition of the reaction layers was determined by energy dispersive spectroscopy (SEM-EDS) and confirmed by X-ray diffraction study. Maximum tensile strength of ~382 MPa along with ~3.7 pct ductility was observed for the joints processed for 60 minutes. It was found that the extent of diffusion zone at Ni/SS interface was greater than that of TiA/Ni interface. From the microhardness profile, fractured surfaces, and fracture path, it was demonstrated that the failure of the joints was initiated and propagated apparently at TiA/Ni interface near Ni3Ti intermetallic for bonding time less than 90 minutes, and through Ni for bonding time 90 minutes and greater.

  1. Antimicrobial Cu-bearing stainless steel scaffolds.

    PubMed

    Wang, Qiang; Ren, Ling; Li, Xiaopeng; Zhang, Shuyuan; Sercombe, Timothy B; Yang, Ke

    2016-11-01

    Copper-bearing stainless steel scaffolds with two different structures (Body Centered Cubic and Gyroid labyrinth) at two solid fractions (25% and 40%) were fabricated from both 316L powder and a mixture of 316L and elemental Cu powder using selective laser melting, and relative 316L scaffolds were served as control group. After processing, the antimicrobial testing demonstrated that the 316L-Cu scaffolds presented excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus, and the cell viability assay indicated that there was no cytotoxic effect of 316L-Cu scaffolds on rat marrow mesenchymal stem cells. As such, these have the potential to reduce implant-associated infections. The Cu was also found to homogeneously distribute within the microstructure by scanning electronic microcopy. The addition of Cu would not significantly affect its strength and stiffness compared to 316L scaffold, and the stiffness of all the scaffolds (3-20GPa) is similar to that of bone and much less than that of bulk stainless steel. Consequently, fabrication of such low stiffness porous structures, especially coupled with the addition of antimicrobial Cu, may provide a new direction for medical stainless steels. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Spherical nanoindentation of proton irradiated 304 stainless steel: A comparison of small scale mechanical test techniques for measuring irradiation hardening

    NASA Astrophysics Data System (ADS)

    Weaver, Jordan S.; Pathak, Siddhartha; Reichardt, Ashley; Vo, Hi T.; Maloy, Stuart A.; Hosemann, Peter; Mara, Nathan A.

    2017-09-01

    Experimentally quantifying the mechanical effects of radiation damage in reactor materials is necessary for the development and qualification of new materials for improved performance and safety. This can be achieved in a high-throughput fashion through a combination of ion beam irradiation and small scale mechanical testing in contrast to the high cost and laborious nature of bulk testing of reactor irradiated samples. The current work focuses on using spherical nanoindentation stress-strain curves on unirradiated and proton irradiated (10 dpa at 360 °C) 304 stainless steel to quantify the mechanical effects of radiation damage. Spherical nanoindentation stress-strain measurements show a radiation-induced increase in indentation yield strength from 1.36 GPa to 2.72 GPa and a radiation-induced increase in indentation work hardening rate of 10 GPa-30 GPa. These measurements are critically compared against Berkovich nanohardness, micropillar compression, and micro-tension measurements on the same material and similar grain orientations. The ratio of irradiated to unirradiated yield strength increases by a similar factor of 2 when measured via spherical nanoindentation or Berkovich nanohardness testing. A comparison of spherical indentation stress-strain curves to uniaxial (micropillar and micro-tension) stress-strain curves was achieved using a simple scaling relationship which shows good agreement for the unirradiated condition and poor agreement in post-yield behavior for the irradiated condition. The disagreement between spherical nanoindentation and uniaxial stress-strain curves is likely due to the plastic instability that occurs during uniaxial tests but is absent during spherical nanoindentation tests.

  3. Spherical nanoindentation of proton irradiated 304 stainless steel: A comparison of small scale mechanical test techniques for measuring irradiation hardening

    DOE PAGES

    Weaver, Jordan S.; Pathak, Siddhartha; Reichardt, Ashley; ...

    2017-06-27

    Experimentally quantifying the mechanical effects of radiation damage in reactor materials is necessary for the development and qualification of new materials for improved performance and safety. This can be achieved in a high-throughput fashion through a combination of ion beam irradiation and small scale mechanical testing in contrast to the high cost and laborious nature of bulk testing of reactor irradiated samples. The current paper focuses on using spherical nanoindentation stress-strain curves on unirradiated and proton irradiated (10 dpa at 360 °C) 304 stainless steel to quantify the mechanical effects of radiation damage. Spherical nanoindentation stress-strain measurements show a radiation-inducedmore » increase in indentation yield strength from 1.36 GPa to 2.72 GPa and a radiation-induced increase in indentation work hardening rate of 10 GPa–30 GPa. These measurements are critically compared against Berkovich nanohardness, micropillar compression, and micro-tension measurements on the same material and similar grain orientations. The ratio of irradiated to unirradiated yield strength increases by a similar factor of 2 when measured via spherical nanoindentation or Berkovich nanohardness testing. A comparison of spherical indentation stress-strain curves to uniaxial (micropillar and micro-tension) stress-strain curves was achieved using a simple scaling relationship which shows good agreement for the unirradiated condition and poor agreement in post-yield behavior for the irradiated condition. Finally, the disagreement between spherical nanoindentation and uniaxial stress-strain curves is likely due to the plastic instability that occurs during uniaxial tests but is absent during spherical nanoindentation tests.« less

  4. Spherical nanoindentation of proton irradiated 304 stainless steel: A comparison of small scale mechanical test techniques for measuring irradiation hardening

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Weaver, Jordan S.; Pathak, Siddhartha; Reichardt, Ashley

    Experimentally quantifying the mechanical effects of radiation damage in reactor materials is necessary for the development and qualification of new materials for improved performance and safety. This can be achieved in a high-throughput fashion through a combination of ion beam irradiation and small scale mechanical testing in contrast to the high cost and laborious nature of bulk testing of reactor irradiated samples. The current paper focuses on using spherical nanoindentation stress-strain curves on unirradiated and proton irradiated (10 dpa at 360 °C) 304 stainless steel to quantify the mechanical effects of radiation damage. Spherical nanoindentation stress-strain measurements show a radiation-inducedmore » increase in indentation yield strength from 1.36 GPa to 2.72 GPa and a radiation-induced increase in indentation work hardening rate of 10 GPa–30 GPa. These measurements are critically compared against Berkovich nanohardness, micropillar compression, and micro-tension measurements on the same material and similar grain orientations. The ratio of irradiated to unirradiated yield strength increases by a similar factor of 2 when measured via spherical nanoindentation or Berkovich nanohardness testing. A comparison of spherical indentation stress-strain curves to uniaxial (micropillar and micro-tension) stress-strain curves was achieved using a simple scaling relationship which shows good agreement for the unirradiated condition and poor agreement in post-yield behavior for the irradiated condition. Finally, the disagreement between spherical nanoindentation and uniaxial stress-strain curves is likely due to the plastic instability that occurs during uniaxial tests but is absent during spherical nanoindentation tests.« less

  5. Stainless steel wear debris of a scoliotic growth guidance system has little local and systemic effect in an animal model.

    PubMed

    Singh, Vaneet; Rawlinson, Jeremy; Hallab, Nadim

    2018-01-11

    Options to treat early-onset scoliosis include guided-growth systems with sliding action between rods and pedicle screws. The wear was previously measured in an in vitro test, and in this in vivo rabbit model, we evaluated the local and systemic biological response to the stainless steel debris. Compared to the previous study, a relatively higher volume of representative wear particles with a median particle size of 0.84 μm were generated. Bolus dosages were injected into the epidural space at L4-L5 for a minimum of 36 rabbits across three treatment groups (negative control, 1.5 mg, and 4.0 mg) and two timepoints (12 and 24 weeks). Gross pathology evaluated distant organs and the injection site with a dorsal laminectomy to examine the epidural space and dosing site. Peri-implanted particle tissues were stained for immunohistochemical and quantitatively analyzed for IL-6 and TNF-α cytokines. Based on ISO 10993-6:2007 scoring, particles in the high-dose group were primarily non-irritant (12 weeks) with one slightly irritant. At 24 weeks, inflammatory cell infiltration was non-existent to minimal with all groups considered non-irritant at the injection site. Material characterization confirmed that particles detected in distant organs were stainless steel or contaminants. At 12 weeks, stainless steel groups demonstrated statistically increased amounts of cytokine levels compared to control but there was a statistical decrease for both at 24 weeks. These findings indicate that stainless steel wear debris, comparable to the expected usage from a simulated growth guidance system, had no discernible untoward biological effects locally and systemically in an animal model. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  6. Nickel-free austenitic stainless steels for medical applications.

    PubMed

    Yang, Ke; Ren, Yibin

    2010-02-01

    The adverse effects of nickel ions being released into the human body have prompted the development of high-nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel in medical stainless steels, the advantages of nitrogen in stainless steels, and emphatically, the development of high-nitrogen nickel-free stainless steels for medical applications. By combining the benefits of stable austenitic structure, high strength and good plasticity, better corrosion and wear resistances, and superior biocompatibility compared to the currently used 316L stainless steel, the newly developed high-nitrogen nickel-free stainless steel is a reliable substitute for the conventional medical stainless steels.

  7. Nickel-free austenitic stainless steels for medical applications

    PubMed Central

    Yang, Ke; Ren, Yibin

    2010-01-01

    The adverse effects of nickel ions being released into the human body have prompted the development of high-nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel in medical stainless steels, the advantages of nitrogen in stainless steels, and emphatically, the development of high-nitrogen nickel-free stainless steels for medical applications. By combining the benefits of stable austenitic structure, high strength and good plasticity, better corrosion and wear resistances, and superior biocompatibility compared to the currently used 316L stainless steel, the newly developed high-nitrogen nickel-free stainless steel is a reliable substitute for the conventional medical stainless steels. PMID:27877320

  8. Nanosecond laser coloration on stainless steel surface.

    PubMed

    Lu, Yan; Shi, Xinying; Huang, Zhongjia; Li, Taohai; Zhang, Meng; Czajkowski, Jakub; Fabritius, Tapio; Huttula, Marko; Cao, Wei

    2017-08-02

    In this work, we present laser coloration on 304 stainless steel using nanosecond laser. Surface modifications are tuned by adjusting laser parameters of scanning speed, repetition rate, and pulse width. A comprehensive study of the physical mechanism leading to the appearance is presented. Microscopic patterns are measured and employed as input to simulate light-matter interferences, while chemical states and crystal structures of composites to figure out intrinsic colors. Quantitative analysis clarifies the final colors and RGB values are the combinations of structural colors and intrinsic colors from the oxidized pigments, with the latter dominating. Therefore, the engineering and scientific insights of nanosecond laser coloration highlight large-scale utilization of the present route for colorful and resistant steels.

  9. Design, Fabrication and Test of a Formation of Two Satellites Connected by a Tether

    DTIC Science & Technology

    2007-08-03

    Device (PMD), consisting of filters and screens , will be integrated into this tank. The shell is manufactured with Stainless Steel 316L with the...internal filters manufactured with Stainless Steel 304L/316L. The internal screens are of expanded aluminum 901A. Table 4 highlights the specifications of...Final Report Submitted to the Air Force Office of Scientific Research University Nanosat Program August 3, 2007 Dr. Kent Miller AFOSR/NE 4015 Wilson

  10. Quantitative Evaluation of Aged AISI 316L Stainless Steel Sensitization to Intergranular Corrosion: Comparison Between Microstructural Electrochemical and Analytical Methods

    NASA Astrophysics Data System (ADS)

    Sidhom, H.; Amadou, T.; Sahlaoui, H.; Braham, C.

    2007-06-01

    The evaluation of the degree of sensitization (DOS) to intergranular corrosion (IGC) of a commercial AISI 316L austenitic stainless steel aged at temperatures ranging from 550 °C to 800 °C during 100 to 80,000 hours was carried out using three different assessment methods. (1) The microstructural method coupled with the Strauss standard test (ASTM A262). This method establishes the kinetics of the precipitation phenomenon under different aging conditions, by transmission electronic microscope (TEM) examination of thin foils and electron diffraction. The subsequent chromium-depleted zones are characterized by X-ray microanalysis using scanning transmission electronic microscope (STEM). The superimposition of microstructural time-temperature-precipitation (TTP) and ASTM A262 time-temperature-sensitization (TTS) diagrams provides the relationship between aged microstructure and IGC. Moreover, by considering the chromium-depleted zone characteristics, sensitization and desensitization criteria could be established. (2) The electrochemical method involving the double loop-electrochemical potentiokinetic reactivation (DL-EPR) test. The operating conditions of this test were initially optimized using the experimental design method on the bases of the reliability, the selectivity, and the reproducibility of test responses for both annealed and sensitized steels. The TTS diagram of the AISI 316L stainless steel was established using this method. This diagram offers a quantitative assessment of the DOS and a possibility to appreciate the time-temperature equivalence of the IGC sensitization and desensitization. (3) The analytical method based on the chromium diffusion models. Using the IGC sensitization and desensitization criteria established by the microstructural method, numerical solving of the chromium diffusion equations leads to a calculated AISI 316L TTS diagram. Comparison of these three methods gives a clear advantage to the nondestructive DL-EPR test when it is

  11. Effects of Grain Size on Ultrasonic Attenuation in Type 316L Stainless Steel

    PubMed Central

    Wan, Tao; Wakui, Takashi; Futakawa, Masatoshi; Obayashi, Hironari

    2017-01-01

    A lead bismuth eutectic (LBE) spallation target will be installed in the Target Test Facility (TEF-T) in the Japan Proton Accelerator Research Complex (J-PARC). The spallation target vessel filled with LBE is made of type 316L stainless steel. However, various damages, such as erosion/corrosion damage and liquid metal embrittlement caused by contact with flowing LBE at high temperature, and irradiation hardening caused by protons and neutrons, may be inflicted on the target vessel, which will deteriorate the steel and might break the vessel. To monitor the target vessel for prevention of an accident, an ultrasonic technique has been proposed to establish off-line evaluation for estimating vessel material status during the target maintenance period. Basic R&D must be carried out to clarify the dependency of ultrasonic wave propagation behavior on material microstructures and obtain fundamental knowledge. As a first step, ultrasonic waves scattered by the grains of type 316L stainless steel are investigated using new experimental and numerical approaches in the present study. The results show that the grain size can be evaluated exactly and quantitatively by calculating the attenuation coefficient of the ultrasonic waves scattered by the grains. The results also show that the scattering regimes of ultrasonic waves depend heavily on the ratio of wavelength to average grain size, and are dominated by grains of extraordinarily large size along the wave propagation path. PMID:28773115

  12. 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.

  13. Metal release rate from AISI 316L stainless steel and pure Fe, Cr and Ni into a synthetic biological medium--a comparison.

    PubMed

    Herting, G; Wallinder, I Odnevall; Leygraf, C

    2008-09-01

    Metal release rates from stainless steel grade 316L were investigated in artificial lysosomal fluid (ALF), simulating a human inflammatory cell response. The main focus was placed on release rates of main alloying elements using graphite furnace atomic absorption spectroscopy, and changes in surface oxide composition by means of X-ray photoelectron spectroscopy. To emphasise that alloys and pure metals possess totally different intrinsic properties, comparative studies were performed on the pure alloying constituents: iron, nickel and chromium. Significant differences in release rates were observed due to the presence of a passive surface film on stainless steel. Iron and nickel were released at rates more than 300 times lower from the 316L alloy compared with the pure metals whereas the release rate of chromium was similar. Iron was preferentially released compared with nickel and chromium. Immersion in ALF resulted in the gradual enrichment of chromium in the surface film, a small increase of nickel, and the reduction of oxidized iron with decreasing release rates of alloy constituents as a result. As expected, released metals from stainless steel grade 316L were neither in proportion to the bulk alloy composition nor to the surface film composition.

  14. 48 CFR 6103.304 - Reply to the audit division and agency responses [Rule 304].

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Reply to the audit division and agency responses [Rule 304]. 6103.304 Section 6103.304 Federal Acquisition Regulations System CIVILIAN BOARD OF CONTRACT APPEALS, GENERAL SERVICES ADMINISTRATION TRANSPORTATION RATE CASES 6103.304 Reply to the audit division and agency...

  15. Investigation of anticorrosion properties of nanocomposites of spray coated zinc oxide and titanium dioxide thin films on stainless steel (304L SS) in saline environment

    NASA Astrophysics Data System (ADS)

    P, Muhamed Shajudheen V.; S, Saravana Kumar; V, Senthil Kumar; Maheswari A, Uma; M, Sivakumar; Rani K, Anitha

    2018-01-01

    The present study reports the anticorrosive nature of nanocomposite thin films of zinc oxide and titanium dioxide on steel substrate (304L SS) using spray coating method. The morphology and chemical constituents of the nanocomposite thin film were characterized by field effect scanning electron microscopy and energy dispersive analysis of x-ray (EDAX) studies. From the EDAX studies, it was observed that nanocomposite coatings of desired stoichiometry can be synthesized using present coating technique. The cyclic voltametric techniques such as Tafel analysis and electrochemical impedance spectroscopy (EIS) analysis were conducted to study the anticorrosion properties of the coatings. The E corr values obtained from Tafel polarization curves of the sample coated with nanocomposites of ZnO and TiO2 in different ratios (5:1, 1:1 and 1:5) indicated that the corrosion resistance was improved compared to bare steel. The coating resistance values obtained from the Nyquist plot after fitting with equivalent circuit confirmed the improved anticorrosion performance of the coated samples. The sample coated with ZnO: TiO2 in the ratio 1:5 showed better corrosion resistance compared to other ratios. The Tafel and EIS studies were repeated after exposure to 5% NaCl for 390 h and the results indicated the anticorrosive nature of the coating in the aggressive environment. The root mean square deviation of surface roughness values calculated from the AFM images before and after salt spray indicated the stability of coating in the saline environment.

  16. Polarization and fluence effects in femtosecond laser induced micro/nano structures on stainless steel with antireflection property

    NASA Astrophysics Data System (ADS)

    Yao, Caizhen; Ye, Yayun; Jia, Baoshen; Li, Yuan; Ding, Renjie; Jiang, Yong; Wang, Yuxin; Yuan, Xiaodong

    2017-12-01

    In this paper, micro/nano structures on stainless steel were prepared in single spot irradiation mode and scan mode by using femtosecond laser technique. The influence of polarization and fluence on the formation of micro/nano structures were explored. Surface morphology, microstructure, roughness and composition of prepared samples were characterized. The antireflection property and wettability of laser treated samples were also tested and compared with that of original stainless steel.Results showed that the laser-induced spot consists of two distinct regions due to the Gaussian beam profile: a core region of moth-eye-like structure and a peripheral region of nanoparticles-covered laser-induced periodic surface structure (NC-LIPSS). The proportion of the core region and dimension of micro/nano structure increase with increasing laser fluence. Polarization can be used to tune the direction of NC-LIPSS. Atomic ratios of Cr and Mn increase and atomic ratio of Ni decreases after laser irradiation. Oxygen is not detected on laser irradiated samples, indicating that oxidation reactions are not significant during the interaction process between femtosecond laser and 304 stainless steel. These are good for the application of stainless steel as its physical properties would not change or even enhanced. The overlaps between two laser scan lines significantly influence the surface roughness and should be controlled carefully during the preparation process. The laser irradiated surface has a better antireflection property in comparison with that of original stainless steel, which may due to the scattering and absorption of micro/nano structures. Contact angle of micro/nano structured stainless steel decreases with the increase of laser fluence. The hydrophilic property can be explained by Wenzel's model. The interference between the surface plasmon wave and the incident light wave leads to the formation of NC-LIPSS.

  17. Microstructural Evolutions During Reversion Annealing of Cold-Rolled AISI 316 Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Naghizadeh, Meysam; Mirzadeh, Hamed

    2018-03-01

    Microstructural evolutions during reversion annealing of a plastically deformed AISI 316 stainless steel were investigated and three distinct stages were identified: the reversion of strain-induced martensite to austenite, the primary recrystallization of the retained austenite, and the grain growth process. It was found that the slow kinetics of recrystallization at lower annealing temperatures inhibit the formation of an equiaxed microstructure and might effectively impair the usefulness of this thermomechanical treatment for the objective of grain refinement. By comparing the behavior of AISI 316 and 304 alloys, it was found that the mentioned slow kinetics is related to the retardation effect of solute Mo in the former alloy. At high reversion annealing temperature, however, an equiaxed austenitic microstructure was achieved quickly in AISI 316 stainless steel due to the temperature dependency of retardation effect of molybdenum, which allowed the process of recrystallization to happen easily. Conclusively, this work can shed some light on the issues of this efficient grain refining approach for microstructural control of austenitic stainless steels.

  18. Microstructural Evolutions During Reversion Annealing of Cold-Rolled AISI 316 Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Naghizadeh, Meysam; Mirzadeh, Hamed

    2018-06-01

    Microstructural evolutions during reversion annealing of a plastically deformed AISI 316 stainless steel were investigated and three distinct stages were identified: the reversion of strain-induced martensite to austenite, the primary recrystallization of the retained austenite, and the grain growth process. It was found that the slow kinetics of recrystallization at lower annealing temperatures inhibit the formation of an equiaxed microstructure and might effectively impair the usefulness of this thermomechanical treatment for the objective of grain refinement. By comparing the behavior of AISI 316 and 304 alloys, it was found that the mentioned slow kinetics is related to the retardation effect of solute Mo in the former alloy. At high reversion annealing temperature, however, an equiaxed austenitic microstructure was achieved quickly in AISI 316 stainless steel due to the temperature dependency of retardation effect of molybdenum, which allowed the process of recrystallization to happen easily. Conclusively, this work can shed some light on the issues of this efficient grain refining approach for microstructural control of austenitic stainless steels.

  19. TRITIUM AND DECAY HELIUM EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL WELDMENTS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Morgan, M; Scott West, S; Michael Tosten, M

    2007-08-31

    J-Integral fracture toughness tests were conducted on tritium-exposed-and-aged Types 304L and 21-6-9 stainless steel weldments in order to measure the combined effects of tritium and its decay product, helium-3 on the fracture toughness properties. Initially, weldments have fracture toughness values about three times higher than base-metal values. Delta-ferrite phase in the weld microstructure improved toughness provided no tritium was present in the microstructure. After a tritium-exposure-and-aging treatment that resulted in {approx}1400 atomic parts per million (appm) dissolved tritium, both weldments and base metals had their fracture toughness values reduced to about the same level. The tritium effect was greater inmore » weldments (67 % reduction vs. 37% reduction) largely because the ductile discontinuous delta-ferrite interfaces were embrittled by tritium and decay helium. Fracture toughness values decreased for both base metals and weldments with increasing decay helium content in the range tested (50-200 appm).« less

  20. In vitro evaluation of corrosion and cytotoxicity of orthodontic brackets.

    PubMed

    Costa, M T; Lenza, M A; Gosch, C S; Costa, I; Ribeiro-Dias, F

    2007-05-01

    The corrosion resistance of AISI 304 stainless steel (AISI 304 SS) and manganese stainless steel (low-nickel SS) brackets in artificial saliva was investigated. The cytotoxic effects of their corrosion products on L929 cell culture were compared by two assays, crystal violet, to evaluate cell viability, and MTT (3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide), for cell metabolism and proliferation. The atomic absorption spectroscopic analysis of the corrosion products demonstrated that nickel and manganese ion concentrations were higher for the AISI 304 SS-bracket immersion solution as compared with the low-nickel SS brackets. Scanning electron microscopy and energy-dispersive spectroscopy demonstrated less corrosion resistance for the AISI 304 SS brackets. Although none of the bracket extracts altered L929 cell viability or morphology, the AISI 304 SS-bracket extracts decreased cellular metabolism slightly. The results indicated that the low-nickel SS presents better in vitro biocompatibility than AISI 304 SS brackets. Abbreviations used: AISI, American Iron and Steel Institute; EDS, energy-dispersive spectroscopy; OD, optical density; ISO, International Organization for Standardization; MTT, (3-{4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; NiSO(4), nickel sulfate; SEM, standard error of the mean; WHO, World Health Organization; and TNF, tumor necrosis factor.

  1. Storability Investigations of Water Long-Term Storage Evaluation

    DTIC Science & Technology

    1974-12-01

    of 17 - 4PH H-1025 Stainless Steel Containers after 19 Storage in Oxygen Free Water, Magnification 3/5X 11 Interior of 17 - 4PH 1-1025 Stainless Steel...Stainless Steel Containers 21 Adherent Metallic Granular Material Found in 17 - 4PH Staluiess 35 Steel Containers. Lower Photo Is Bright Area Shown in Figure...material. Hence, the selected materials are: 304L stainless steel, A-286, 17 - 4PH stainless steel, Inconel 718 and 6A1-4V titanium. During fabrication, some

  2. 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.

  3. Enhanced photocathodic protection performance of Ag/graphene/TiO2 composite for 304SS under visible light.

    PubMed

    Li, Hong; Wang, Xiutong; Wei, Qinyi; Liu, Xueqing; Qian, Zhouhai; Hou, Baorong

    2017-06-02

    Ag and graphene co-sensitized TiO 2 composites were successfully fabricated and used as photoanodes for photogenerated cathodic protection of 304 stainless steel (304SS) under visible light. Graphene films was firstly deposited onto the TiO 2 nanotube (NT) films via cyclic voltammetric electrodeposition. Ag/graphene/TiO 2 films were then fabricated via dipping and photoreduction method. The morphology, composition and optical response of the Ag/graphene/TiO 2 NT composites were characterized by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, UV-vis diffusion reflectance spectroscopy, respectively. The photocathodic protection performance of the Ag/graphene/TiO 2 composites were systematically studied through open-circuit potential and potentiodynamic polarization measurements in 3.5 wt% NaCl solution under visible light (λ > 400 nm). The composites exhibited enhanced photogenerated cathodic protection performance for 304SS under visible light irradiation compared to pure TiO 2 . Graphene and Ag have a synergistic effect on the enhancement of photocathodic protection performance of TiO 2 . The composites prepared with 30-cycle graphene film and 15 mM AgNO 3 solution showed the optimal corrosion protection performance.

  4. Enhanced photocathodic protection performance of Ag/graphene/TiO2 composite for 304SS under visible light

    NASA Astrophysics Data System (ADS)

    Li, Hong; Wang, Xiutong; Wei, Qinyi; Liu, Xueqing; Qian, Zhouhai; Hou, Baorong

    2017-06-01

    Ag and graphene co-sensitized TiO2 composites were successfully fabricated and used as photoanodes for photogenerated cathodic protection of 304 stainless steel (304SS) under visible light. Graphene films was firstly deposited onto the TiO2 nanotube (NT) films via cyclic voltammetric electrodeposition. Ag/graphene/TiO2 films were then fabricated via dipping and photoreduction method. The morphology, composition and optical response of the Ag/graphene/TiO2 NT composites were characterized by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, UV-vis diffusion reflectance spectroscopy, respectively. The photocathodic protection performance of the Ag/graphene/TiO2 composites were systematically studied through open-circuit potential and potentiodynamic polarization measurements in 3.5 wt% NaCl solution under visible light (λ > 400 nm). The composites exhibited enhanced photogenerated cathodic protection performance for 304SS under visible light irradiation compared to pure TiO2. Graphene and Ag have a synergistic effect on the enhancement of photocathodic protection performance of TiO2. The composites prepared with 30-cycle graphene film and 15 mM AgNO3 solution showed the optimal corrosion protection performance.

  5. Reactor Materials Program - Baseline Material Property Handbook - Mechanical Properties of 1950's Vintage Stainless Steel Weldment Components, Task Number 89-23-A-1

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stoner, K.J.

    1999-11-05

    The Process Water System (primary coolant) piping of the nuclear production reactors constructed in the 1950''s at Savannah River Site is comprised primarily of Type 304 stainless steel with Type 308 stainless steel weld filler. A program to measure the mechanical properties of archival PWS piping and weld materials (having approximately six years of service at temperatures between 25 and 100 degrees C) has been completed. The results from the mechanical testing has been synthesized to provide a mechanical properties database for structural analyses of the SRS piping.

  6. Fibrinogen adsorption onto 316L stainless steel under polarized conditions.

    PubMed

    Gettens, Robert T T; Gilbert, Jeremy L

    2008-04-01

    Adsorption of the plasma protein fibrinogen onto electrically polarized 316L stainless steel was observed and quantified using both in situ and ex situ atomic force microscopy (AFM) techniques. Significant differences in fibrinogen adsorption were observed across voltages. Ex situ studies showed significantly lower area coverage (theta) and height of adsorbed Fb on cathodically polarized surfaces when compared to anodically polarized surfaces. Conformational differences in the protein may explain the distinctions in Fb surface area coverage (theta) and height between the anodic and cathodic cases. In situ studies showed significantly slower kinetics of Fb adsorption onto surfaces below -100 mV (vs. Ag/AgCl) compared to surfaces polarized above -100 mV. Electrochemical current density data showed large charge transfer processes (approximately 1 x 10(-5) to 1 x 10(-4) A/cm(2)) taking place on the 316L SS surfaces at voltages below -100 mV (vs. Ag/AgCl). These relatively large current densities point to flux of ionic species away from the surface as a major source of the reduction in adsorption kinetics rather than just hydrophilic or electrostatic effects. Copyright 2007 Wiley Periodicals, Inc.

  7. Microstructural Characteristics of Plasma Nitrided Layer on Hot-Rolled 304 Stainless Steel with a Small Amount of α-Ferrite

    NASA Astrophysics Data System (ADS)

    Xu, Xiaolei; Yu, Zhiwei; Cui, Liying; Niu, Xinjun; Cai, Tao

    2016-02-01

    The hot-rolled 304 stainless steel with γ-austenite and approximately 5 pct α-ferrite elongated along the rolling direction was plasma-nitrided at a low temperature of 693 K (420 °C). X-ray diffraction results revealed that the nitrided layer was mainly composed of the supersaturated solid solution of nitrogen in austenite ( γ N). Transmission electron microscopy (TEM) observations showed that the microstructure of the γ N phase exhibited "fracture factor contrast" reflective of the occurrence of fine pre-precipitations in γ N by the continuous precipitation. The occurrence of a diffuse scattering effect on the electron diffraction spots of γ N indicated that the pre-precipitation took place in γ N in the form of strongly bonded Cr-N clusters or pairs due to a strong attractive interaction of nitrogen with chromium. Scanning electron microscopy and TEM observations indicated that the discontinuous precipitation initiated from the γ/ α interfaces and grew from the austenite boundaries into austenite grains to form a lamellar structure consisting of CrN and ferrite. The orientation relationship between CrN and ferrite corresponded to a Baker-Nutting relationship: (100)CrN//(100) α ; [011]CrN//[001] α . A zigzag boundary line following the banded structure of alternating γ-austenite and elongated α-ferrite was presented between the nitrided layer and the substrate to form a continuous varying layer thickness, which resulted from the difference in diffusivities of nitrogen in α-ferrite and γ-austenite, along the γ/ α interfaces and through the lattice. Microstructural features similar to the γ N were also revealed in the ferrite of the nitrided layer by TEM. It was not excluded that a supersaturated solid solution of nitrogen in ferrite ( α N) formed in the nitrided layer.

  8. Properties of super stainless steels for orthodontic applications.

    PubMed

    Oh, Keun-Taek; Kim, Young-Sik; Park, Yong-Soo; Kim, Kyoung-Nam

    2004-05-15

    Orthodontic stainless-steel appliances are considered to be corrosion resistant, but localized corrosion can occur in the oral cavity. This study was undertaken to evaluate the properties of super stainless steels in orthodontic applications. Accordingly, the metallurgical properties, mechanical properties, corrosion resistance, amount of the released nickel, cytotoxicity, and characteristics of the passive film were investigated. Corrosion resistances of the specimens were high and in the following order: super austenitic stainless steel (SR-50A) > super ferritic stainless steel (SFSS) = super duplex stainless steel (SR-6DX) > 316L SS > super martensitic stainless steel (SR-3Mo) in artificial saliva, 37 degrees C. At 500 mV (SCE), current densities of SR-50A, SFSS, SR-6DX, 316L SS, and SR-3Mo were 5.96 microA/cm(2), 20.3 microA/cm(2), 31.9 microA/cm(2), 805 microA/cm(2), and 5.36 mA/cm(2), respectively. Open circuit potentials of SR-50A, 316L SS, SR-6DX, SR-3Mo, and SFSS were - 0.2, - 0.22, - 0.24, - 0.43, and - 0.46 V (SCE), respectively. SR-50A, SFSS, and SR-6DX released below 3 ng/ml nickel for 8 weeks, and increased a little with immersion time, and 316L SS released about 3.5 ng/ml nickel, but SR-3Mo released a large amount of nickel, which increased with immersion time. The study demonstrated that SR-50A, SR-6DX, and SFSS have high corrosion resistance and mild or no cytotoxicity, due to the passive film enhanced by synergistic effect of Mo + N or by high addition effect of Cr + W. All super stainless steels showed very low cytotoxicity regardless of their nickel contents, although SR-3Mo was found to be relatively cytotoxic. From these studies, these steels are considered suitable for orthodontic applications. Copyright 2004 Wiley Periodicals, Inc.

  9. 50 CFR 300.304 - Prohibitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Prohibitions. 300.304 Section 300.304... Vessels on IUU Vessel Lists § 300.304 Prohibitions. (a) It is unlawful for a foreign, listed IUU vessel... arrangement with a listed IUU vessel. (d) The prohibitions listed in § 300.304(c) shall not apply when the...

  10. 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.

  11. 77 FR 48149 - Columbia Gas Transmission, L.L.C.; Notice of Request Under Blanket Authorization

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-13

    ... Transmission, L.L.C.; Notice of Request Under Blanket Authorization Take notice that on July 24, 2012 Columbia Gas Transmission, L.L.C. (Columbia), P.O. Box 1273, Charleston, West Virginia 25325, filed in Docket... Transmission, L.L.C., P.O. Box 1273, Charleston, West Virginia 25325, or call (304) 357-2359, or fax (304) 357...

  12. Nickel-free stainless steel avoids neointima formation following coronary stent implantation

    PubMed Central

    Fujiu, Katsuhito; Manabe, Ichiro; Sasaki, Makoto; Inoue, Motoki; Iwata, Hiroshi; Hasumi, Eriko; Komuro, Issei; Katada, Yasuyuki; Taguchi, Tetsushi; Nagai, Ryozo

    2012-01-01

    SUS316L stainless steel and cobalt–chromium and platinum–chromium alloys are widely used platforms for coronary stents. These alloys also contain nickel (Ni), which reportedly induces allergic reactions in some subjects and is known to have various cellular effects. The effects of Ni on neointima formation after stent implantation remain unknown, however. We developed coronary stents made of Ni-free high-nitrogen austenitic stainless steel prepared using a N2-gas pressurized electroslag remelting (P-ESR) process. Neointima formation and inflammatory responses following stent implantation in porcine coronary arteries were then compared between the Ni-free and SUS316L stainless steel stents. We found significantly less neointima formation and inflammation in arteries implanted with Ni-free stents, as compared to SUS316L stents. Notably, Ni2+ was eluted into the medium from SUS316L but not from Ni-free stainless steel. Mechanistically, Ni2+ increased levels of hypoxia inducible factor protein-1α (HIF-1α) and its target genes in cultured smooth muscle cells. HIF-1α and their target gene levels were also increased in the vascular wall at SUS316L stent sites but not at Ni-free stent sites. The Ni-free stainless steel coronary stent reduces neointima formation, in part by avoiding activation of inflammatory processes via the Ni-HIF pathway. The Ni-free-stainless steel stent is a promising new coronary stent platform. PMID:27877545

  13. Nickel-free stainless steel avoids neointima formation following coronary stent implantation.

    PubMed

    Fujiu, Katsuhito; Manabe, Ichiro; Sasaki, Makoto; Inoue, Motoki; Iwata, Hiroshi; Hasumi, Eriko; Komuro, Issei; Katada, Yasuyuki; Taguchi, Tetsushi; Nagai, Ryozo

    2012-12-01

    SUS316L stainless steel and cobalt-chromium and platinum-chromium alloys are widely used platforms for coronary stents. These alloys also contain nickel (Ni), which reportedly induces allergic reactions in some subjects and is known to have various cellular effects. The effects of Ni on neointima formation after stent implantation remain unknown, however. We developed coronary stents made of Ni-free high-nitrogen austenitic stainless steel prepared using a N 2 -gas pressurized electroslag remelting (P-ESR) process. Neointima formation and inflammatory responses following stent implantation in porcine coronary arteries were then compared between the Ni-free and SUS316L stainless steel stents. We found significantly less neointima formation and inflammation in arteries implanted with Ni-free stents, as compared to SUS316L stents. Notably, Ni 2+ was eluted into the medium from SUS316L but not from Ni-free stainless steel. Mechanistically, Ni 2+ increased levels of hypoxia inducible factor protein-1 α (HIF-1 α ) and its target genes in cultured smooth muscle cells. HIF-1 α and their target gene levels were also increased in the vascular wall at SUS316L stent sites but not at Ni-free stent sites. The Ni-free stainless steel coronary stent reduces neointima formation, in part by avoiding activation of inflammatory processes via the Ni-HIF pathway. The Ni-free-stainless steel stent is a promising new coronary stent platform.

  14. Improving Corrosion Resistance of 316L Austenitic Stainless Steel Using ZrO2 Sol-Gel Coating in Nitric Acid Solution

    NASA Astrophysics Data System (ADS)

    Kazazi, Mahdi; Haghighi, Milad; Yarali, Davood; Zaynolabedini, Masoomeh H.

    2018-03-01

    In this study, thin-film coating of zirconium oxide (ZrO2) was prepared by sol-gel method and subsequent heat treatment process. The sol was prepared by controlled hydrolysis of zirconium tetrapropoxide using acetic acid and ethanol/acetylacetone mixture as catalyst and chelating agent, respectively, and finally deposited onto the 316L austenitic stainless steel (316L SS) using dip coating method in order to improve its corrosion resistance in nitric acid medium. The composition, structure, and morphology of the coated surface were investigated by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The obtained results from XRD and FTIR state the formation of tetragonal and monoclinic ZrO2 phase. Also, the obtained results from surface morphology investigation by SEM and AFM indicate the formation of smooth, homogeneous and uniform coatings on the steel substrate. Then, the corrosion behavior of stainless steel was investigated in a 1 and 10 M nitric acid solutions using electrochemical impedance spectroscopy and linear polarization test. The obtained results from these tests for ZrO2-coated specimens indicated a considerable improvement in the corrosion resistance of 316L stainless steel by an increase in corrosion potential and transpassive potential, and a decrease in passive current density and corrosion current density. The decrease in passive current density in both the concentration of solutions was two orders of magnitude from bare to coated specimens.

  15. High performance computation of residual stress and distortion in laser welded 301L stainless sheets

    DOE PAGES

    Huang, Hui; Tsutsumi, Seiichiro; Wang, Jiandong; ...

    2017-07-11

    Transient thermo-mechanical simulation of stainless plate laser welding process was performed by a highly efficient and accurate approach-hybrid iterative substructure and adaptive mesh method. Especially, residual stress prediction was enhanced by considering various heat effects in the numerical model. The influence of laser welding heat input on residual stress and welding distortion of stainless thin sheets were investigated by experiment and simulation. X-ray diffraction (XRD) and contour method were used to measure the surficial and internal residual stress respectively. Effect of strain hardening, annealing and melting on residual stress prediction was clarified through a parametric study. It was shown thatmore » these heat effects must be taken into account for accurate prediction of residual stresses in laser welded stainless sheets. Reasonable agreement among residual stresses by numerical method, XRD and contour method was obtained. Buckling type welding distortion was also well reproduced by the developed thermo-mechanical FEM.« less

  16. High performance computation of residual stress and distortion in laser welded 301L stainless sheets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, Hui; Tsutsumi, Seiichiro; Wang, Jiandong

    Transient thermo-mechanical simulation of stainless plate laser welding process was performed by a highly efficient and accurate approach-hybrid iterative substructure and adaptive mesh method. Especially, residual stress prediction was enhanced by considering various heat effects in the numerical model. The influence of laser welding heat input on residual stress and welding distortion of stainless thin sheets were investigated by experiment and simulation. X-ray diffraction (XRD) and contour method were used to measure the surficial and internal residual stress respectively. Effect of strain hardening, annealing and melting on residual stress prediction was clarified through a parametric study. It was shown thatmore » these heat effects must be taken into account for accurate prediction of residual stresses in laser welded stainless sheets. Reasonable agreement among residual stresses by numerical method, XRD and contour method was obtained. Buckling type welding distortion was also well reproduced by the developed thermo-mechanical FEM.« less

  17. 48 CFR 1827.304 - Procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Procedures. 1827.304 Section 1827.304 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION... 1827.304 Procedures. ...

  18. Effect of tritium and decay helium on the fracture toughness properties of stainless steel weldments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    2008-07-15

    J-Integral fracture toughness tests were conducted on tritium-exposed-and- aged Types 304L and 21-6-9 stainless steel weldments in order to measure the combined effects of tritium and its decay product, helium-3 on the fracture toughness properties. Initially, weldments have fracture toughness values about three times higher than base-metal values. Delta-ferrite phase in the weld microstructure improved toughness provided no tritium was present in the microstructure. After a tritium-exposure-and-aging treatment that resulted in {approx}1400 atomic parts per million (appm) dissolved tritium, both weldments and base metals had their fracture toughness values reduced to about the same level. The tritium effect was greatermore » in weldments (67 % reduction vs. 37% reduction) largely because the ductile discontinuous delta-ferrite phase was embrittled by tritium and decay helium. For both base metals and weldments, fracture toughness values decreased with increasing decay helium content in the range tested (50-800 appm). (authors)« less

  19. Investigation of Boron addition and compaction pressure on the compactibility, densification and microhardness of 316L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Ali, S.; Rani, A. M. A.; Altaf, K.; Baig, Z.

    2018-04-01

    Powder Metallurgy (P/M) is one of the continually evolving technologies used for producing metal materials of various sizes and shapes. However, some P/M materials have limited use in engineering for their performance deficiency including fully dense components. AISI 316L Stainless Steel (SS) is one of the promising materials used in P/M that combines outstanding corrosion resistance, strength and ductility for numerous applications. It is important to analyze the material composition along with the processing conditions that lead to a superior behaviour of the parts manufactured with P/M technique. This research investigates the effect of Boron addition on the compactibility, densification, sintering characteristics and microhardness of 316L SS parts produced with P/M. In this study, 0.25% Boron was added to the 316L Stainless Steel matrix to study the increase in densification of the 316L SS samples. The samples were made at different compaction pressures ranging from 100 MPa to 600 MPa and sintered in Nitrogen atmosphere at a temperature of 1200°C. The effect of compaction pressure and sintering temperature and atmosphere on the density and microhardness was evaluated. The microstructure of the samples was examined by optical microscope and microhardness was found using Vickers hardness machine. Results of the study showed that sintered samples with Boron addition exhibited high densification with increase in microhardness as compared to pure 316L SS sintered samples.

  20. The Role of Deformation and Microchemistry in the Corrosion Processes of Type 304 Stainless Steel in Simulated Pressurized Water Reactor Environments

    NASA Astrophysics Data System (ADS)

    Fisher, Kevin B.

    Degradation of structural components in nuclear environments is a limiting factor in the lifetime of nuclear power plants. Despite decades of research on the topic, there are still aspects of the degradation phenomena that are not well understood, leading to premature failure of components that can be both expensive to repair and potentially dangerous. The current work addresses the role of material deformation on the corrosion phenomena of 304 SS in a simulated nuclear reactor environment by studying the relationship of the material microstructure and microchemistry with the resulting corrosion products using a multiscale analysis approach. The general corrosion phenomenon was studied in relation to the surface deformation of the material, and it was determined that surface deformation not only increases the rate of oxidation, but also has a pronounced impact on the microchemical structure of the oxide film when compared to undeformed material. These findings were applied to understanding the role of deformation in the more complex corrosion phenomena of stress corrosion cracking (SCC) and corrosion fatigue cracking (CFC). In SCC experiments, material deformation in the form of cold work played a synergistic role with unique microchemical features of the materials studied to promote the cracking process under certain environmental and material heat treatment conditions. Despite the fact that the materials studied were low carbon heats of 304L SS thought to be immune to the sensitization and therefore resistant to SCC, elevated boron and delta ferrites in the material were implicated in the SCC susceptibility after heat treatment. On the other hand, low levels of residual deformation played only a minor role in the corrosion processes occurring during CFC experiments over a wide range of rise times. Instead, deformation was suspected to play a larger role in the mechanical cracking response of the material. By studying multiple corrosion processes of 304 SS a

  1. Performance of ferritic stainless steels for automobile muffler corrosion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tarutani, Y.; Hashizume, T.

    1995-11-01

    Corrosion behavior of ferritic stainless steels was studied in artificial exhaust gas condensates containing corrosive ions such as Cl{sup {minus}} and SO{sub 3}{sup 2{minus}}. Continuous immersion tests in flasks and Dip and Dry tests by using the alternate corrosion tester with a heating system clarified the effects of chromium and molybdenum additions on the corrosion resistance of a ferritic stainless steel in the artificial exhaust gas condensates. Effects of surface oxidation on the corrosion behavior were investigated in a temperature range of 573K to 673K. Oxidation of 673K reduced the corrosion resistance of the ferritic stainless steels in the artificialmore » environment of the automobile muffler. Particulate matter deposited on the muffler inner shell from the automobile exhaust gas was also examined. Deposited particulate matter increased the corrosion rate of the ferritic stainless steel. Finally, the authors also investigated the corrosion of the automobile mufflers made of Type 436L ferritic stainless steel with 18% chromium-1.2% molybdenum after 24 months, in Japan. The sets of results clarified that Type 436L ferritic stainless steel as the material for the automobile muffler exhibited acceptable corrosion resistance.« less

  2. Remote reactor repair: GTA (gas tungsten Arc) weld cracking caused by entrapped helium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kanne, Jr, W R

    1988-01-01

    A repair patch was welded to the wall of a nuclear reactor tank using remotely controlled thirty-foot long robot arms. Further repair was halted when gas tungsten arc (GTA) welds joining type 304L stainless steel patches to the 304 stainless steel wall developed toe cracks in the heat-affected zone (HAZ). The role of helium in cracking was investigated using material with entrapped helium from tritium decay. As a result of this investigation, and of an extensive array of diagnostic tests performed on reactor tank wall material, helium embrittlement was shown to be the cause of the toe cracks.

  3. Electrochemical characterization of AISI 316L stainless steel in contact with simulated body fluid under infection conditions.

    PubMed

    López, Danián Alejandro; Durán, Alicia; Ceré, Silvia Marcela

    2008-05-01

    Titanium and cobalt alloys, as well as some stainless steels, are among the most frequently used materials in orthopaedic surgery. In industrialized countries, stainless steel devices are used only for temporary implants due to their lower corrosion resistance in physiologic media when compared to other alloys. However, due to economical reasons, the use of stainless steel alloys for permanent implants is very common in developing countries. The implantation of foreign bodies is sometimes necessary in the modern medical practice. However, the complex interactions between the host and the can implant weaken the local immune system, increasing the risk of infections. Therefore, it is necessary to further study these materials as well as the characteristics of the superficial film formed in physiologic media in infection conditions in order to control their potential toxicity due to the release of metallic ions in the human body. This work presents a study of the superficial composition and the corrosion resistance of AISI 316L stainless steel and the influence of its main alloying elements when they are exposed to an acidic solution that simulates the change of pH that occurs when an infection develops. Aerated simulated body fluid (SBF) was employed as working solution at 37 degrees C. The pH was adjusted to 7.25 and 4 in order to reproduce normal body and disease state respectively. Corrosion resistance was measured by means of electrochemical impedance spectroscopy (EIS) and anodic polarization curves.

  4. Stainless steel corrosion scale formed in reclaimed water: Characteristics, model for scale growth and metal element release.

    PubMed

    Cui, Yong; Liu, Shuming; Smith, Kate; Hu, Hongying; Tang, Fusheng; Li, Yuhong; Yu, Kanghua

    2016-10-01

    Stainless steels generally have extremely good corrosion resistance, but are still susceptible to pitting corrosion. As a result, corrosion scales can form on the surface of stainless steel after extended exposure to aggressive aqueous environments. Corrosion scales play an important role in affecting water quality. These research results showed that interior regions of stainless steel corrosion scales have a high percentage of chromium phases. We reveal the morphology, micro-structure and physicochemical characteristics of stainless steel corrosion scales. Stainless steel corrosion scale is identified as a podiform chromite deposit according to these characteristics, which is unlike deposit formed during iron corrosion. A conceptual model to explain the formation and growth of stainless steel corrosion scale is proposed based on its composition and structure. The scale growth process involves pitting corrosion on the stainless steel surface and the consecutive generation and homogeneous deposition of corrosion products, which is governed by a series of chemical and electrochemical reactions. This model shows the role of corrosion scales in the mechanism of iron and chromium release from pitting corroded stainless steel materials. The formation of corrosion scale is strongly related to water quality parameters. The presence of HClO results in higher ferric content inside the scales. Cl - and SO 4 2- ions in reclaimed water play an important role in corrosion pitting of stainless steel and promote the formation of scales. Copyright © 2016. Published by Elsevier B.V.

  5. 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.

  6. 45 CFR 304.95 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 2 2011-10-01 2011-10-01 false [Reserved] 304.95 Section 304.95 Public Welfare Regulations Relating to Public Welfare OFFICE OF CHILD SUPPORT ENFORCEMENT (CHILD SUPPORT ENFORCEMENT PROGRAM... § 304.95 [Reserved] ...

  7. 45 CFR 304.27 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 2 2011-10-01 2011-10-01 false [Reserved] 304.27 Section 304.27 Public Welfare Regulations Relating to Public Welfare OFFICE OF CHILD SUPPORT ENFORCEMENT (CHILD SUPPORT ENFORCEMENT PROGRAM... § 304.27 [Reserved] ...

  8. [Study of a new medical stainless steel].

    PubMed

    Ren, Yibin; Yang, Ke; Zhang, Bingchun; Yang, Huibin

    2006-10-01

    Medical implantable stainless steels are widely used in medical field due to their excellent properties, besides its allergic response to human body, the nickel ion released from the steels due to corrosion has the harm of malformation and carcingenesis. The mechanical property, corrosion resistance and blood compatibility of a new nickel-free stainless steel (BIOSSN4) is researched in this paper. Compared with the traditional 316L medical stainless steel, BIOSSN4 shows wide future applications because of its better combination of strength and toughness, good corrosion resistance and biocompatibility.

  9. An assessment of cold work effects on strain-controlled low-cycle fatigue behavior of type 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Rao, K. Bhanu Sankara; Valsan, M.; Sandhya, R.; Mannan, S. L.; Rodriguez, P.

    1993-04-01

    The influence of prior cold work (PCW) on low-cycle fatigue (LCF) behavior of type 304 stainless steel has been studied at 300, 823, 923, and 1023 K by conducting total axial strain-controlled tests in solution annealed (SA, 0 pct PCW) condition and on specimens having three levels of PCW, namely, 10, 20, and 30 pct. A triangular waveform with a constant frequency of 0.1 Hz was employed for all of the tests performed over strain amplitudes in the range of ±0.25 to ± 1.25 pct. These studies have revealed that fatigue life is strongly dependent on PCW, temperature, and strain amplitude employed in testing. The SA material generally displayed better endurance in terms of total and plastic strain amplitudes than the material in 10, 20, and 30 pct PCW conditions at all of the temperatures. However, at 300 K at very low strain amplitudes, PCW material exhibited better total strain fatigue resistance. At 823 K, LCF life decreased with increasing PCW, whereas at 923 K, 10 pct PCW displayed the lowest life. An improvement in life occurred for prior deformations exceeding 10 pct at all strain amplitudes at 923 K. Fatigue life showed a noticeable decrease with increasing temperature up to 1023 K in PCW state. On the other hand, SA material displayed a minimum in fatigue life at 923 K. The fatigue life results of SA as well as all of the PCW conditions obeyed the Basquin and Coffin-Manson relationships at 300, 823, and 923 K. The constants and exponents in these equations were found to depend on the test temperature and prior metallurgical state of the material. A study is made of cyclic stress-strain behavior in SA and PCW states and the relationship between the cyclic strain-hardening exponent and fatigue behavior at different temperatures has been explored. The influence of environment on fatigue crack initiation and propagation behavior has been examined.

  10. A New Vacuum Brazing Route for Niobium-316L Stainless Steel Transition Joints for Superconducting RF Cavities

    NASA Astrophysics Data System (ADS)

    Kumar, Abhay; Ganesh, P.; Kaul, R.; Bhatnagar, V. K.; Yedle, K.; Ram Sankar, P.; Sindal, B. K.; Kumar, K. V. A. N. P. S.; Singh, M. K.; Rai, S. K.; Bose, A.; Veerbhadraiah, T.; Ramteke, S.; Sridhar, R.; Mundra, G.; Joshi, S. C.; Kukreja, L. M.

    2015-02-01

    The paper describes a new approach for vacuum brazing of niobium-316L stainless steel transition joints for application in superconducting radiofrequency cavities. The study exploited good wettability of titanium-activated silver-base brazing alloy (CuSil-ABA®), along with nickel as a diffusion barrier, to suppress brittle Fe-Nb intermetallic formation, which is well reported during the established vacuum brazing practice using pure copper filler. The brazed specimens displayed no brittle intermetallic layers on any of its interfaces, but instead carried well-distributed intermetallic particles in the ductile matrix. The transition joints displayed room temperature tensile and shear strengths of 122-143 MPa and 80-113 MPa, respectively. The joints not only exhibited required hermeticity (helium leak rate <1.1 × 10-10 mbar l/s) for service in ultra-high vacuum but also withstood twelve hour degassing heat treatment at 873 K (suppresses Q-disease in niobium cavities), without any noticeable degradation in the microstructure and the hermeticity. The joints retained their leak tightness even after undergoing ten thermal cycles between the room temperature and the liquid nitrogen temperature, thereby establishing their ability to withstand service-induced low cycle fatigue conditions. The study proposes a new lower temperature brazing route to form niobium-316L stainless steel transition joints, with improved microstructural characteristics and acceptable hermeticity and mechanical properties.

  11. Size-separated particle fractions of stainless steel welding fume particles - A multi-analytical characterization focusing on surface oxide speciation and release of hexavalent chromium.

    PubMed

    Mei, N; Belleville, L; Cha, Y; Olofsson, U; Odnevall Wallinder, I; Persson, K-A; Hedberg, Y S

    2018-01-15

    Welding fume of stainless steels is potentially health hazardous. The aim of this study was to investigate the manganese (Mn) and chromium (Cr) speciation of welding fume particles and their extent of metal release relevant for an inhalation scenario, as a function of particle size, welding method (manual metal arc welding, metal arc welding using an active shielding gas), different electrodes (solid wires and flux-cored wires) and shielding gases, and base alloy (austenitic AISI 304L and duplex stainless steel LDX2101). Metal release investigations were performed in phosphate buffered saline (PBS), pH 7.3, 37°, 24h. The particles were characterized by means of microscopic, spectroscopic, and electroanalytical methods. Cr was predominantly released from particles of the welding fume when exposed in PBS [3-96% of the total amount of Cr, of which up to 70% as Cr(VI)], followed by Mn, nickel, and iron. Duplex stainless steel welded with a flux-cored wire generated a welding fume that released most Cr(VI). Nano-sized particles released a significantly higher amount of nickel compared with micron-sized particle fractions. The welding fume did not contain any solitary known chromate compounds, but multi-elemental highly oxidized oxide(s) (iron, Cr, and Mn, possibly bismuth and silicon). Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  12. 48 CFR 932.304 - Procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Procedures. 932.304 Section 932.304 Federal Acquisition Regulations System DEPARTMENT OF ENERGY GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Loan Guarantees for Defense Production 932.304 Procedures. ...

  13. 48 CFR 32.304 - Procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Procedures. 32.304 Section 32.304 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Loan Guarantees for Defense Production 32.304 Procedures. ...

  14. 48 CFR 1432.304 - Procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Procedures. 1432.304 Section 1432.304 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Loan Guarantees for Defense Production 1432.304 Procedures. ...

  15. 48 CFR 13.304 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false [Reserved] 13.304 Section 13.304 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES SIMPLIFIED ACQUISITION PROCEDURES Simplified Acquisition Methods 13.304 [Reserved] ...

  16. 48 CFR 1227.304 - Procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Procedures. 1227.304 Section 1227.304 Federal Acquisition Regulations System DEPARTMENT OF TRANSPORTATION GENERAL CONTRACTING REQUIREMENTS PATENTS, DATA, AND COPYRIGHTS Patent Rights Under Government Contracts 1227.304 Procedures. ...

  17. 48 CFR 1327.304 - Procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Procedures. 1327.304 Section 1327.304 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE GENERAL CONTRACTING REQUIREMENTS PATENTS, DATA, AND COPYRIGHTS Patent Rights Under Government Contracts 1327.304 Procedures. ...

  18. 48 CFR 27.304 - Procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Procedures. 27.304 Section 27.304 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS PATENTS, DATA, AND COPYRIGHTS Patent Rights under Government Contracts 27.304 Procedures. ...

  19. 48 CFR 627.304 - Procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Procedures. 627.304 Section 627.304 Federal Acquisition Regulations System DEPARTMENT OF STATE GENERAL CONTRACTING REQUIREMENTS PATENTS, DATA, AND COPYRIGHTS Patent Rights Under Government Contracts 627.304 Procedures. ...

  20. 49 CFR 179.400-5 - Materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-5 Materials. (a) Stainless steel of ASTM A 240/A 240M (IBR, see § 171.7 of this subchapter), Type 304 or 304L must be used... the lading. (b) Any steel casting, steel forging, steel structural shape or carbon steel plate used to...

  1. 49 CFR 179.400-5 - Materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-5 Materials. (a) Stainless steel of ASTM A 240/A 240M (IBR, see § 171.7 of this subchapter), Type 304 or 304L must be used... the lading. (b) Any steel casting, steel forging, steel structural shape or carbon steel plate used to...

  2. 49 CFR 179.400-5 - Materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-5 Materials. (a) Stainless steel of ASTM A 240/A 240M (IBR, see § 171.7 of this subchapter), Type 304 or 304L must be used... the lading. (b) Any steel casting, steel forging, steel structural shape or carbon steel plate used to...

  3. 49 CFR 179.400-5 - Materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-5 Materials. (a) Stainless steel of ASTM A 240/A 240M (IBR, see § 171.7 of this subchapter), Type 304 or 304L must be used... the lading. (b) Any steel casting, steel forging, steel structural shape or carbon steel plate used to...

  4. High temperature corrosion of austenitic stainless steel coils in a direct reduction plant in Mexico

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Juarez-Islas, J.A.; Campillo, B.; Chaudhary, N.

    1996-08-01

    The subject of this study is related to the performance of austenitic steels coils and tubes, in a range of temperatures between 425 to 870 C for the transport of reducing gases, in an installation involving the direct reduction of iron-ore by reforming natural gas. Evidence is presented that metal dusting is not the only unique high temperature corrosion mechanism that caused catastrophic failures of austenitic 304 (UNS S30400) coils and HK-40 (UNS J94204) tubes. Sensitization as well as stress corrosion cracking occurred in 304 stainless steel coils, and metal dusting occurred in tubes of HK-40, a high resistance alloy.more » The role of a continuous injection of H{sub 2}S to the process is suggested to avoid the high temperature metal dusting corrosion mechanism found in these kind of installations.« less

  5. 23 CFR 450.304 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Definitions. 450.304 Section 450.304 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.304 Definitions. Except as otherwise...

  6. 23 CFR 450.304 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Definitions. 450.304 Section 450.304 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.304 Definitions. Except as otherwise...

  7. 23 CFR 450.304 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Definitions. 450.304 Section 450.304 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.304 Definitions. Except as otherwise...

  8. 49 CFR 1016.304 - Reply.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 8 2011-10-01 2011-10-01 false Reply. 1016.304 Section 1016.304 Transportation... BOARD ADJUDICATORY PROCEEDINGS Procedures for Considering Applications § 1016.304 Reply. Within 15 days... supporting affidavits or a request for further proceedings under § 1016.307. ...

  9. 49 CFR 1016.304 - Reply.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Reply. 1016.304 Section 1016.304 Transportation... BOARD ADJUDICATORY PROCEEDINGS Procedures for Considering Applications § 1016.304 Reply. Within 15 days... supporting affidavits or a request for further proceedings under § 1016.307. ...

  10. 48 CFR 927.304 - Procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Procedures. 927.304 Section 927.304 Federal Acquisition Regulations System DEPARTMENT OF ENERGY GENERAL CONTRACTING REQUIREMENTS PATENTS, DATA, AND COPYRIGHTS Patent Rights Under Government Contracts 927.304 Procedures. Where...

  11. 48 CFR 1427.304 - Procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Procedures. 1427.304 Section 1427.304 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR GENERAL CONTRACTING REQUIREMENTS PATENTS, DATA, AND COPYRIGHTS Patent Rights Under Government Contracts. 1427.304 Procedures. ...

  12. 48 CFR 304.602 - General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false General. 304.602 Section 304.602 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATIVE MATTERS Contract Reporting 304.602 General. HHS' Departmental Contracts Information System (DCIS) captures...

  13. 48 CFR 9.304 - Exceptions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Exceptions. 9.304 Section 9.304 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS First Article Testing and Approval 9.304 Exceptions. Normally, testing and approval...

  14. 23 CFR 450.304 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Definitions. 450.304 Section 450.304 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.304 Definitions. Except as otherwise...

  15. 23 CFR 450.304 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Definitions. 450.304 Section 450.304 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.304 Definitions. Except as otherwise...

  16. 7 CFR 1205.304 - Cotton.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Cotton. 1205.304 Section 1205.304 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Cotton Research and Promotion Order Definitions § 1205.304 Cotton. Cotton means: (a) All Upland cotton harvested...

  17. 7 CFR 1205.304 - Cotton.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Cotton. 1205.304 Section 1205.304 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Cotton Research and Promotion Order Definitions § 1205.304 Cotton. Cotton means: (a) All Upland cotton harvested...

  18. 7 CFR 1205.304 - Cotton.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Cotton. 1205.304 Section 1205.304 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Cotton Research and Promotion Order Definitions § 1205.304 Cotton. Cotton means: (a) All Upland cotton harvested...

  19. 7 CFR 1205.304 - Cotton.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Cotton. 1205.304 Section 1205.304 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Cotton Research and Promotion Order Definitions § 1205.304 Cotton. Cotton means: (a) All Upland cotton harvested...

  20. 7 CFR 1205.304 - Cotton.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Cotton. 1205.304 Section 1205.304 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Cotton Research and Promotion Order Definitions § 1205.304 Cotton. Cotton means: (a) All Upland cotton harvested...

  1. 40 CFR 82.304 - Prohibitions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Prohibitions. 82.304 Section 82.304 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) PROTECTION OF STRATOSPHERIC OZONE Ban on Refrigeration and Air-Conditioning Appliances Containing HCFCs § 82.304 Prohibitions...

  2. 40 CFR 82.304 - Prohibitions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Prohibitions. 82.304 Section 82.304 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) PROTECTION OF STRATOSPHERIC OZONE Ban on Refrigeration and Air-Conditioning Appliances Containing HCFCs § 82.304 Prohibitions...

  3. 40 CFR 82.304 - Prohibitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Prohibitions. 82.304 Section 82.304 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) PROTECTION OF STRATOSPHERIC OZONE Ban on Refrigeration and Air-Conditioning Appliances Containing HCFCs § 82.304 Prohibitions...

  4. 40 CFR 82.304 - Prohibitions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Prohibitions. 82.304 Section 82.304 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) PROTECTION OF STRATOSPHERIC OZONE Ban on Refrigeration and Air-Conditioning Appliances Containing HCFCs § 82.304 Prohibitions...

  5. 40 CFR 82.304 - Prohibitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Prohibitions. 82.304 Section 82.304 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) PROTECTION OF STRATOSPHERIC OZONE Ban on Refrigeration and Air-Conditioning Appliances Containing HCFCs § 82.304 Prohibitions...

  6. 44 CFR 304.4 - Allocations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Allocations. 304.4 Section 304.4 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS CONSOLIDATED GRANTS TO INSULAR AREAS § 304.4 Allocations. For each Federal fiscal...

  7. 40 CFR 304.10 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 27 2010-07-01 2010-07-01 false Purpose. 304.10 Section 304.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND... § 304.10 Purpose. This regulation establishes and governs procedures for the arbitration of EPA cost...

  8. 7 CFR 1210.304 - Board.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Board. 1210.304 Section 1210.304 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... PLAN Watermelon Research and Promotion Plan Definitions § 1210.304 Board. Board means the National...

  9. 48 CFR 304.7100 - Policy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Policy. 304.7100 Section 304.7100 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATIVE MATTERS Review and Approval of Proposed Contract Actions 304.7100 Policy. (a) The HCA (non-delegable...

  10. 44 CFR 304.2 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Definitions. 304.2 Section 304.2 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS CONSOLIDATED GRANTS TO INSULAR AREAS § 304.2 Definitions. Except as otherwise stated...

  11. 48 CFR 244.304 - Surveillance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Surveillance. 244.304 Section 244.304 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... Reviews 244.304 Surveillance. (b) The ACO, or the purchasing system analyst (PSA) with the concurrence of...

  12. 5 CFR 304.101 - Coverage.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Coverage. 304.101 Section 304.101 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EXPERT AND CONSULTANT APPOINTMENTS § 304.101 Coverage. These regulations apply to the appointment of experts and consultants as...

  13. 5 CFR 304.101 - Coverage.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Coverage. 304.101 Section 304.101 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EXPERT AND CONSULTANT APPOINTMENTS § 304.101 Coverage. These regulations apply to the appointment of experts and consultants as...

  14. 5 CFR 304.101 - Coverage.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Coverage. 304.101 Section 304.101 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EXPERT AND CONSULTANT APPOINTMENTS § 304.101 Coverage. These regulations apply to the appointment of experts and consultants as...

  15. 5 CFR 304.101 - Coverage.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Coverage. 304.101 Section 304.101 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EXPERT AND CONSULTANT APPOINTMENTS § 304.101 Coverage. These regulations apply to the appointment of experts and consultants as...

  16. 5 CFR 304.101 - Coverage.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Coverage. 304.101 Section 304.101 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EXPERT AND CONSULTANT APPOINTMENTS § 304.101 Coverage. These regulations apply to the appointment of experts and consultants as...

  17. Anti-biofouling superhydrophobic surface fabricated by picosecond laser texturing of stainless steel

    NASA Astrophysics Data System (ADS)

    Sun, Ke; Yang, Huan; Xue, Wei; He, An; Zhu, Dehua; Liu, Wenwen; Adeyemi, Kenneth; Cao, Yu

    2018-04-01

    Anti-biofouling technology is based on specifically designed materials and coatings. This is an enduring goal in the maritime industries, such as shipping, offshore oil exploration, and aquaculture. Recently, research of the relationship between wettability and antifouling effectiveness has attracted considerable attention, due to the anti-biofouling properties of the lotus leaf and shark skin. In this study, super-hydrophobic surfaces (SHSs) with controllable periodic structures were fabricated on AISI304 stainless steel by a picosecond laser, and their anti-biofouling performance were investigated by seawater immersion for five weeks in summertime. The results showed that the specimens with SHS demonstrate significant anti-biofouling effect as compared with the bare stainless steel plate. We observed that nearly 50% decrease of the average microbe attachment area ratio (Avg. MAAR) could be obtained. The micro-groove SHS with more abundant hierarchical micro-nano structures showed better anti-biofouling performance than the micro-pit SHS.

  18. Microstructure and Mechanical Properties of Friction Stir Welded Aluminum Alloy/Stainless Steel Lap Joints

    NASA Astrophysics Data System (ADS)

    Ogura, Tomo; Nishida, Taichi; Nishida, Hidehito; Yoshikawa, Syuhei; Yoshida, Takumi; Omichi, Noriko; Fujimoto, Mitsuo; Hirose, Akio

    The mechanical properties and interfacial microstructure of an aluminum alloy/stainless steel dissimilar lap joint using friction stir welding (FSW) were characterized. In an FSWed A3003 aluminum alloy-SUS304 steel lap joint, the strength on the advancing side was larger than that at the retreating side. TEM observation indicated that a sound joint can be obtained from the stage of the formation of the amorphous layer owing to the mechanical alloying effects before the formation of intermetallic compounds. This lap joining technique was also successfully applied to A6061-T6 aluminum alloy-grooved SUS304 plates. The maximum tensile strength of the lap joint was approximately the same as that of the base alloy, however, the proof stress of the joint decreased with the dissolution of the β″ phase in the A6061 aluminium alloy, which is caused by the generation of heat during friction stir welding.

  19. 17 CFR 229.304 - (Item 304) Changes in and disagreements with accountants on accounting and financial disclosure.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... disagreements with accountants on accounting and financial disclosure. 229.304 Section 229.304 Commodity and...-REGULATION S-K Financial Information § 229.304 (Item 304) Changes in and disagreements with accountants on... subsequent interim period, an independent accountant who was previously engaged as the principal accountant...

  20. 17 CFR 229.304 - (Item 304) Changes in and disagreements with accountants on accounting and financial disclosure.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... disagreements with accountants on accounting and financial disclosure. 229.304 Section 229.304 Commodity and...-REGULATION S-K Financial Information § 229.304 (Item 304) Changes in and disagreements with accountants on... subsequent interim period, an independent accountant who was previously engaged as the principal accountant...

  1. 17 CFR 229.304 - (Item 304) Changes in and disagreements with accountants on accounting and financial disclosure.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... disagreements with accountants on accounting and financial disclosure. 229.304 Section 229.304 Commodity and...-REGULATION S-K Financial Information § 229.304 (Item 304) Changes in and disagreements with accountants on... subsequent interim period, an independent accountant who was previously engaged as the principal accountant...

  2. 17 CFR 229.304 - (Item 304) Changes in and disagreements with accountants on accounting and financial disclosure.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... disagreements with accountants on accounting and financial disclosure. 229.304 Section 229.304 Commodity and...-REGULATION S-K Financial Information § 229.304 (Item 304) Changes in and disagreements with accountants on... subsequent interim period, an independent accountant who was previously engaged as the principal accountant...

  3. 28 CFR 24.304 - Settlement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Settlement. 24.304 Section 24.304... DEPARTMENT OF JUSTICE ADMINISTRATIVE PROCEEDINGS Procedures for Considering Applications § 24.304 Settlement. A prevailing party and Department counsel may agree on a proposed settlement of an award before...

  4. 31 CFR 537.304 - Entity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Entity. 537.304 Section 537.304 Money... CONTROL, DEPARTMENT OF THE TREASURY BURMESE SANCTIONS REGULATIONS General Definitions § 537.304 Entity. The term entity means a partnership, association, trust, joint venture, corporation, group, subgroup...

  5. 31 CFR 537.304 - Entity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Entity. 537.304 Section 537.304 Money... CONTROL, DEPARTMENT OF THE TREASURY BURMESE SANCTIONS REGULATIONS General Definitions § 537.304 Entity. The term entity means a partnership, association, trust, joint venture, corporation, group, subgroup...

  6. 5 CFR 2610.304 - Reply.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Reply. 2610.304 Section 2610.304 Administrative Personnel OFFICE OF GOVERNMENT ETHICS ORGANIZATION AND PROCEDURES IMPLEMENTATION OF THE EQUAL ACCESS TO JUSTICE ACT Procedures for Considering Applications § 2610.304 Reply. Within 15 days after...

  7. 7 CFR 1942.304 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 13 2011-01-01 2009-01-01 true Definitions. 1942.304 Section 1942.304 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... § 1942.304 Definitions. Project. For rural business enterprise grants, the result of the use of program...

  8. 16 CFR 304.3 - Applicability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Applicability. 304.3 Section 304.3 Commercial Practices FEDERAL TRADE COMMISSION REGULATIONS UNDER SPECIFIC ACTS OF CONGRESS RULES AND REGULATIONS UNDER THE HOBBY PROTECTION ACT § 304.3 Applicability. Any person engaged in the manufacturing, or...

  9. 5 CFR 610.304 - Coverage.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Coverage. 610.304 Section 610.304 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Administrative Dismissals of Daily, Hourly, and Piecework Employees § 610.304 Coverage. This subpart applies to regular...

  10. 5 CFR 610.304 - Coverage.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Coverage. 610.304 Section 610.304 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Administrative Dismissals of Daily, Hourly, and Piecework Employees § 610.304 Coverage. This subpart applies to regular...

  11. 5 CFR 610.304 - Coverage.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Coverage. 610.304 Section 610.304 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Administrative Dismissals of Daily, Hourly, and Piecework Employees § 610.304 Coverage. This subpart applies to regular...

  12. 5 CFR 610.304 - Coverage.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Coverage. 610.304 Section 610.304 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Administrative Dismissals of Daily, Hourly, and Piecework Employees § 610.304 Coverage. This subpart applies to regular...

  13. 5 CFR 610.304 - Coverage.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Coverage. 610.304 Section 610.304 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS HOURS OF DUTY Administrative Dismissals of Daily, Hourly, and Piecework Employees § 610.304 Coverage. This subpart applies to regular...

  14. 31 CFR 551.304 - Interest.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Interest. 551.304 Section 551.304 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SOMALIA SANCTIONS REGULATIONS General Definitions § 551.304...

  15. Corrosion resistance of lithium/iodine batteries fabricated in an extremely dry environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brown, W.R.; Holmes, C.F.; Stinebring, R.C.

    1981-10-01

    Early lithium/iodine pacemaker batteries employed considerable amounts of inert plastic materials to encase the active ingredients inside the stainless steel case. Several years ago the Wilson Greatbatch Ltd. (WGL) Model 755 cell was introduced and represented a significant change in lithium/iodine battery construction. In this design (1) the iodinepolyvinylpyridine (PVP) depolarizer material was placed in direct contact with the 304L stainless steel case and much of the inert material was eliminated. This change resulted in obtaining substantially more depolarizer in the battery thereby greatly increasing the electrical capacity for the same cell volume. A study was instituted to evaluate possiblemore » corrosion effects between the iodine in the depolarizer and the stainless steel case.« less

  16. Deformation history and load sequence effects on cumulative fatigue damage and life predictions

    NASA Astrophysics Data System (ADS)

    Colin, Julie

    Fatigue loading seldom involves constant amplitude loading. This is especially true in the cooling systems of nuclear power plants, typically made of stainless steel, where thermal fluctuations and water turbulent flow create variable amplitude loads, with presence of mean stresses and overloads. These complex loading sequences lead to the formation of networks of microcracks (crazing) that can propagate. As stainless steel is a material with strong deformation history effects and phase transformation resulting from plastic straining, such load sequence and variable amplitude loading effects are significant to its fatigue behavior and life predictions. The goal of this study was to investigate the effects of cyclic deformation on fatigue behavior of stainless steel 304L as a deformation history sensitive material and determine how to quantify and accumulate fatigue damage to enable life predictions under variable amplitude loading conditions for such materials. A comprehensive experimental program including testing under fully-reversed, as well as mean stress and/or mean strain conditions, with initial or periodic overloads, along with step testing and random loading histories was conducted on two grades of stainless steel 304L, under both strain-controlled and load-controlled conditions. To facilitate comparisons with a material without deformation history effects, similar tests were also carried out on aluminum 7075-T6. Experimental results are discussed, including peculiarities observed with stainless steel behavior, such as a phenomenon, referred to as secondary hardening characterized by a continuous increase in the stress response in a strain-controlled test and often leading to runout fatigue life. Possible mechanisms for secondary hardening observed in some tests are also discussed. The behavior of aluminum is shown not to be affected by preloading, whereas the behavior of stainless steel is greatly influenced by prior loading. Mean stress relaxation in

  17. Irradiation creep-fatigue interaction of type 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Scholz, R.; Mueller, R.

    1996-10-01

    Type 316L stainless steel samples in both, 20% cold-worked (cw) and recrystallised (rc) conditions were exposed to strain controlled fatigue cycling in torsion at 400°C during an irradiation with 19 MeV deuterons. The effect of irradiation creep induced stress relaxation on the fatigue life was studied by imposing a hold time at the minimum strain value in the loading cycle. For the cw material at strain ranges of 1.13% and 1.3%, the absolute stress values, τ H, maintained during the hold time decreased with the number of cycles due to the irradiation creep induced stress relaxation. A mean stress was built up. The number of cycles to failure was considerably reduced in comparison to continuous cycling tests under thermal conditions. For the rc material at strain ranges of 1.03% and 1.4%, the values of τ H increased with the number of cycles, despite the hold time imposed, due to irradiation and/or cyclic hardening.

  18. Analysis of in vivo corrosion of 316L stainless steel posterior thoracolumbar plate systems: a retrieval study.

    PubMed

    Majid, Kamran; Crowder, Terence; Baker, Erin; Baker, Kevin; Koueiter, Denise; Shields, Edward; Herkowitz, Harry N

    2011-12-01

    One hundred eighteen patients retrieved 316L stainless steel thoracolumbar plates, of 3 different designs, used for fusion in 60 patients were examined for evidence of corrosion. A medical record review and statistical analysis were also carried out. This study aims to identify types of corrosion and examine preferential metal ion release and the possibility of statistical correlation to clinical effects. Earlier studies have found that stainless steel spine devices showed evidence of mild-to-severe corrosion; fretting and crevice corrosion were the most commonly reported types. Studies have also shown the toxicity of metal ions released from stainless steel corrosion and how the ions may adversely affect bone formation and/or induce granulomatous foreign body responses. The retrieved plates were visually inspected and graded based on the degree of corrosion. The plates were then analyzed with optical microscopy, scanning electron microscopy, and energy dispersive x-ray spectroscopy. A retrospective medical record review was performed and statistical analysis was carried out to determine any correlations between experimental findings and patient data. More than 70% of the plates exhibited some degree of corrosion. Both fretting and crevice corrosion mechanisms were observed, primarily at the screw plate interface. Energy dispersive x-ray spectroscopy analysis indicated reductions in nickel content in corroded areas, suggestive of nickel ion release to the surrounding biological environment. The incidence and severity of corrosion was significantly correlated with the design of the implant. Stainless steel thoracolumbar plates show a high incidence of corrosion, with statistical dependence on device design.

  19. 14 CFR 1245.304 - Procedures.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Procedures. 1245.304 Section 1245.304 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PATENTS AND OTHER INTELLECTUAL PROPERTY RIGHTS NASA Foreign Patent Program § 1245.304 Procedures. (a) The patent counsel at each NASA field...

  20. 14 CFR 1245.304 - Procedures.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Procedures. 1245.304 Section 1245.304 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PATENTS AND OTHER INTELLECTUAL PROPERTY RIGHTS NASA Foreign Patent Program § 1245.304 Procedures. (a) The patent counsel at each NASA field...

  1. 30 CFR 585.304 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false [Reserved] 585.304 Section 585.304 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY AND... and Easement Grants for Renewable Energy Activities Row Grants and Rue Grants § 585.304 [Reserved...

  2. 30 CFR 585.304 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false [Reserved] 585.304 Section 585.304 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY AND... and Easement Grants for Renewable Energy Activities Row Grants and Rue Grants § 585.304 [Reserved...

  3. 31 CFR 546.304 - Entity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Entity. 546.304 Section 546.304 Money... CONTROL, DEPARTMENT OF THE TREASURY DARFUR SANCTIONS REGULATIONS General Definitions § 546.304 Entity. The term entity means a partnership, association, trust, joint venture, corporation, group, subgroup, or...

  4. 31 CFR 576.304 - Entity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Entity. 576.304 Section 576.304 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS... Definitions § 576.304 Entity. The term entity means a partnership, association, trust, joint venture...

  5. 31 CFR 546.304 - Entity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Entity. 546.304 Section 546.304 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY DARFUR SANCTIONS REGULATIONS General Definitions § 546.304 Entity. The...

  6. 44 CFR 304.1 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Purpose. 304.1 Section 304.1 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS CONSOLIDATED GRANTS TO INSULAR AREAS § 304.1 Purpose. The purpose of the regulations in this part...

  7. Magnetic resonance imaging of microstructure transition in stainless steel.

    PubMed

    Peeters, Johannes M; van Faassen, Ernst E H; Bakker, Chris J G

    2006-06-01

    Magnetic resonance images are prone to artifacts caused by metallic objects. Such artifacts may not only hamper image interpretation, but also have been shown to provide information about the magnetic properties of the substances involved. In this work, we aim to explore the potential of MRI to detect, localize and characterize changes in magnetic properties that may occur when certain alloys have been exposed to a thermomechanical stress. For this purpose, stainless steel 304 L wires were drawn to induce a change from paramagnetic austenitic into ferromagnetic martensitic microstructure. The changes in magnetic behavior were quantified by analyzing the geometric distortion in spin echo and the geometric distortion and intravoxel dephasing in gradient echo images at 0.5, 1.5 and 3 T. The results of both imaging strategies were in agreement and in accordance with independent measurements with a vibrating sample magnetometer. Drawing wire to 2% of its cross-sectional area was found to increase the volume fraction of the ferromagnetic martensite from 0.3% to 80% and to enhance the magnetization up to two or three orders of magnitude. The results demonstrate the potential of MRI to locate and quantify stress-induced changes in the magnetic properties of alloys in a completely noninvasive and nondestructive way.

  8. Modeling of the Weld Shape Development During the Autogenous Welding Process by Coupling Welding Arc with Weld Pool

    NASA Astrophysics Data System (ADS)

    Dong, Wenchao; Lu, Shanping; Li, Dianzhong; Li, Yiyi

    2010-10-01

    A numerical model of the welding arc is coupled to a model for the heat transfer and fluid flow in the weld pool of a SUS304 stainless steel during a moving GTA welding process. The described model avoids the use of the assumption of the empirical Gaussian boundary conditions, and at the same time, provides reliable boundary conditions to analyze the weld pool. Based on the two-dimensional axisymmetric numerical modeling of the argon arc, the heat flux to workpiece, the input current density, and the plasma drag stress are obtained. The arc temperature contours, the distributions of heat flux, and current density at the anode are in fair agreement with the reported experimental results. Numerical simulation and experimental studies to the weld pool development are carried out for a moving GTA welding on SUS304 stainless steel with different oxygen content from 30 to 220 ppm. The calculated result show that the oxygen can change the Marangoni convection from outward to inward direction on the liquid pool surface and make the wide shallow weld shape become narrow deep one. The calculated result for the weld shape and weld D/W ratio agrees well with the experimental one.

  9. 14 CFR 1209.304 - Membership.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Membership. 1209.304 Section 1209.304 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION BOARDS AND COMMITTEES Contract Adjustment Board § 1209.304 Membership. The Board will consist of a chairperson and four other members, all of whom...

  10. 22 CFR 304.5 - Investigations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 2 2011-04-01 2009-04-01 true Investigations. 304.5 Section 304.5 Foreign Relations PEACE CORPS CLAIMS AGAINST GOVERNMENT UNDER FEDERAL TORT CLAIMS ACT Procedures § 304.5 Investigations. The Peace Corps may investigate, or the General Counsel may request any other Federal agency to...

  11. 22 CFR 304.5 - Investigations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 2 2014-04-01 2014-04-01 false Investigations. 304.5 Section 304.5 Foreign Relations PEACE CORPS CLAIMS AGAINST GOVERNMENT UNDER FEDERAL TORT CLAIMS ACT Procedures § 304.5 Investigations. The Peace Corps may investigate, or the General Counsel may request any other Federal agency to...

  12. 5 CFR 304.103 - Authority.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Authority. 304.103 Section 304.103... APPOINTMENTS § 304.103 Authority. (a) Basic authority. (1) When authorized by an appropriation or other statute... expert or consultant who works on a strictly intermittent basis may be appointed under this authority...

  13. 5 CFR 304.107 - Reports.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Reports. 304.107 Section 304.107 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EXPERT AND CONSULTANT APPOINTMENTS § 304.107 Reports. As required by 5 U.S.C. 3109(e), each agency shall report to the Office of...

  14. 5 CFR 304.107 - Reports.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Reports. 304.107 Section 304.107 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EXPERT AND CONSULTANT APPOINTMENTS § 304.107 Reports. As required by 5 U.S.C. 3109(e), each agency shall report to the Office of...

  15. 5 CFR 304.107 - Reports.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Reports. 304.107 Section 304.107 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EXPERT AND CONSULTANT APPOINTMENTS § 304.107 Reports. As required by 5 U.S.C. 3109(e), each agency shall report to the Office of...

  16. 5 CFR 304.107 - Reports.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Reports. 304.107 Section 304.107 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS EXPERT AND CONSULTANT APPOINTMENTS § 304.107 Reports. As required by 5 U.S.C. 3109(e), each agency shall report to the Office of...

  17. Ultrasonic Non Linearity Characterization of the Stainless Steel Wire Reinforced Aluminium Composite

    NASA Astrophysics Data System (ADS)

    Kim, C. S.; Park, T. S.; Park, I. K.; Hyun, C. Y.

    2009-03-01

    The effectiveness of the ultrasonic nonlinearity measurement for nearly closed cracks was demonstrated for hot pressing and extrusion of stainless steel 304 short wire reinforced aluminum composite. Aluminum based composites show considerable potential in the aerospace industry and the automotive industry due to their high specific strength and low thermal expansion coefficient. The ultrasonic nonlinearity (β/β0) increased with the volume fraction of SSF and aging heat treatment because of the generation of microvoids resulted from localized SSF and matrix precipitation. This study demonstrates the potential for characterization of reinforced composite materials fabricated by the powder metallurgy technique.

  18. Dual-species biofilm of Listeria monocytogenes and Escherichia coli on stainless steel surface.

    PubMed

    de Grandi, Aline Zago; Pinto, Uelinton Manoel; Destro, Maria Teresa

    2018-04-12

    Listeria monocytogenes is a Gram-positive bacterium commonly associated with foodborne diseases. Due its ability to survive under adverse environmental conditions and to form biofilm, this bacterium is a major concern for the food industry, since it can compromise sanitation procedures and increase the risk of post-processing contamination. Little is known about the interaction between L. monocytogenes and Gram-negative bacteria on biofilm formation. Thus, in order to evaluate this interaction, Escherichia coli and L. monocytogenes were tested for their ability to form biofilms together or in monoculture. We also aimed to evaluate the ability of L. monocytogenes 1/2a and its isogenic mutant strain (ΔprfA ΔsigB) to form biofilm in the presence of E. coli. We assessed the importance of the virulence regulators, PrfA and σ B , in this process since they are involved in many aspects of L. monocytogenes pathogenicity. Biofilm formation was assessed using stainless steel AISI 304 #4 slides immersed into brain heart infusion broth, reconstituted powder milk and E. coli preconditioned medium at 25 °C. Our results indicated that a higher amount of biofilm was formed by the wild type strain of L. monocytogenes than by its isogenic mutant, indicating that prfA and sigB are important for biofilm development, especially maturation under our experimental conditions. The presence of E. coli or its metabolites in preconditioned medium did not influence biofilm formation by L. monocytogenes. Our results confirm the possibility of concomitant biofilm formation by L. monocytogenes and E. coli, two bacteria of major significance in the food industry.

  19. 21 CFR 522.304 - Carprofen.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Carprofen. 522.304 Section 522.304 Food and Drugs..., AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.304 Carprofen. (a) Specifications. Each milliliter of solution contains 50 milligrams (mg) carprofen. (b) Sponsor. See No. 000069 in...

  20. 21 CFR 522.304 - Carprofen.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Carprofen. 522.304 Section 522.304 Food and Drugs..., AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.304 Carprofen. (a) Specifications. Each milliliter of solution contains 50 milligrams (mg) carprofen. (b) Sponsor. See No. 000069 in...

  1. 21 CFR 522.304 - Carprofen.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Carprofen. 522.304 Section 522.304 Food and Drugs..., AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.304 Carprofen. (a) Specifications. Each milliliter of solution contains 50 milligrams (mg) carprofen. (b) Sponsor. See No. 054771 in...

  2. 21 CFR 522.304 - Carprofen.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Carprofen. 522.304 Section 522.304 Food and Drugs..., AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.304 Carprofen. (a) Specifications. Each milliliter of solution contains 50 milligrams (mg) carprofen. (b) Sponsor. See No. 000069 in...

  3. 21 CFR 522.304 - Carprofen.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Carprofen. 522.304 Section 522.304 Food and Drugs..., AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.304 Carprofen. (a) Specifications. Each milliliter of solution contains 50 milligrams (mg) carprofen. (b) Sponsor. See No. 000069 in...

  4. 10 CFR 800.304 - Default.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Default. 800.304 Section 800.304 Energy DEPARTMENT OF ENERGY LOANS FOR BID OR PROPOSAL PREPARATION BY MINORITY BUSINESS ENTERPRISES SEEKING DOE CONTRACTS AND ASSISTANCE Loan Administration § 800.304 Default. (a) In the event that the borrower fails to perform the...

  5. 12 CFR 304.3 - Reports.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 5 2012-01-01 2012-01-01 false Reports. 304.3 Section 304.3 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION PROCEDURE AND RULES OF PRACTICE FORMS, INSTRUCTIONS, AND REPORTS § 304.3 Reports. (a) Consolidated Reports of Condition and Income, Forms FFIEC 031 and 041. Pursuant to...

  6. 12 CFR 304.3 - Reports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 4 2011-01-01 2011-01-01 false Reports. 304.3 Section 304.3 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION PROCEDURE AND RULES OF PRACTICE FORMS, INSTRUCTIONS, AND REPORTS § 304.3 Reports. (a) Consolidated Reports of Condition and Income, Forms FFIEC 031 and 041. Pursuant to...

  7. 12 CFR 304.3 - Reports.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Reports. 304.3 Section 304.3 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION PROCEDURE AND RULES OF PRACTICE FORMS, INSTRUCTIONS, AND REPORTS § 304.3 Reports. (a) Consolidated Reports of Condition and Income, Forms FFIEC 031 and 041. Pursuant to...

  8. 12 CFR 304.3 - Reports.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Reports. 304.3 Section 304.3 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION PROCEDURE AND RULES OF PRACTICE FORMS, INSTRUCTIONS, AND REPORTS § 304.3 Reports. (a) Consolidated Reports of Condition and Income, Forms FFIEC 031 and 041. Pursuant to...

  9. Electrochemical Impedance Spectroscopy Of Metal Alloys

    NASA Technical Reports Server (NTRS)

    Macdowell, L. G.; Calle, L. M.

    1993-01-01

    Report describes use of electrochemical impedance spectroscopy (EIS) to investigate resistances of 19 alloys to corrosion under conditions similar to those of corrosive, chloride-laden seaside environment of Space Transportation System launch site. Alloys investigated: Hastelloy C-4, C-22, C-276, and B-2; Inconel(R) 600, 625, and 825; Inco(R) G-3; Monel 400; Zirconium 702; Stainless Steel 304L, 304LN, 316L, 317L, and 904L; 20Cb-3; 7Mo+N; ES2205; and Ferralium 255. Results suggest electrochemical impedance spectroscopy used to predict corrosion performances of metal alloys.

  10. Development of high-temperature Kolsky compression bar techniques for recrystallization investigation

    NASA Astrophysics Data System (ADS)

    Song, B.; Antoun, B. R.; Boston, M.

    2012-05-01

    We modified the design originally developed by Kuokkala's group to develop an automated high-temperature Kolsky compression bar for characterizing high-rate properties of 304L stainless steel at elevated temperatures. Additional features have been implemented to this high-temperature Kolsky compression bar for recrystallization investigation. The new features ensure a single loading on the specimen and precise time and temperature control for quenching to the specimen after dynamic loading. Dynamic compressive stress-strain curves of 304L stainless steel were obtained at 21, 204, 427, 649, and 871 °C (or 70, 400, 800, 1200, and 1600 °F) at the same constant strain rate of 332 s-1. The specimen subjected to specific time and temperature control for quenching after a single dynamic loading was preserved for investigating microstructure recrystallization.

  11. 31 CFR 562.304 - Interest.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Interest. 562.304 Section 562.304... Definitions § 562.304 Interest. Except as otherwise provided in this part, the term interest, when used with respect to property (e.g., “an interest in property”), means an interest of any nature whatsoever, direct...

  12. 31 CFR 589.304 - Interest.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Interest. 589.304 Section 589.304... § 589.304 Interest. Except as otherwise provided in this part, the term interest, when used with respect to property (e.g., “an interest in property”), means an interest of any nature whatsoever, direct or...

  13. 31 CFR 588.304 - Interest.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Interest. 588.304 Section 588.304... § 588.304 Interest. Except as otherwise provided in this part, the term interest, when used with respect to property (e.g., “an interest in property”), means an interest of any nature whatsoever, direct or...

  14. 31 CFR 562.304 - Interest.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Interest. 562.304 Section 562.304... Definitions § 562.304 Interest. Except as otherwise provided in this part, the term interest, when used with respect to property (e.g., “an interest in property”), means an interest of any nature whatsoever, direct...

  15. 31 CFR 588.304 - Interest.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Interest. 588.304 Section 588.304... § 588.304 Interest. Except as otherwise provided in this part, the term interest, when used with respect to property (e.g., “an interest in property”), means an interest of any nature whatsoever, direct or...

  16. 31 CFR 588.304 - Interest.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Interest. 588.304 Section 588.304... § 588.304 Interest. Except as otherwise provided in this part, the term interest, when used with respect to property (e.g., “an interest in property”), means an interest of any nature whatsoever, direct or...

  17. 31 CFR 562.304 - Interest.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Interest. 562.304 Section 562.304... Definitions § 562.304 Interest. Except as otherwise provided in this part, the term interest, when used with respect to property (e.g., “an interest in property”), means an interest of any nature whatsoever, direct...

  18. 31 CFR 562.304 - Interest.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Interest. 562.304 Section 562.304... Definitions § 562.304 Interest. Except as otherwise provided in this part, the term interest, when used with respect to property (e.g., “an interest in property”), means an interest of any nature whatsoever, direct...

  19. 31 CFR 558.304 - Interest.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Interest. 558.304 Section 558.304....304 Interest. Except as otherwise provided in this part, the term interest, when used with respect to property (e.g., “an interest in property”), means an interest of any nature whatsoever, direct or indirect. ...

  20. 31 CFR 588.304 - Interest.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Interest. 588.304 Section 588.304... § 588.304 Interest. Except as otherwise provided in this part, the term interest, when used with respect to property (e.g., “an interest in property”), means an interest of any nature whatsoever, direct or...