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Sample records for alloys stainless steel

  1. Radiation resistant austenitic stainless steel alloys

    DOEpatents

    Maziasz, P.J.; Braski, D.N.; Rowcliffe, A.F.

    1987-02-11

    An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from 0.1 to 0.2% niobium; from 0.1 to 0.6% vanadium; from 0.06 to 0.12% carbon; from 0.01 to 0.03% nitrogen; from 0.03 to 0.08% phosphorus; from 0.005 to 0.01% boron; and the balance iron, and wherein the alloy may be thermomechanically treated to enhance physical and mechanical properties. 4 figs.

  2. Radiation resistant austenitic stainless steel alloys

    DOEpatents

    Maziasz, Philip J.; Braski, David N.; Rowcliffe, Arthur F.

    1989-01-01

    An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from 0.1 to 0.2% niobium; from 0.1 to 0.6% vanadium; from 0.06 to 0.12% carbon; from 0.01% to 0.03% nitrogen; from 0.03 to 0.08% phosphorus; from 0.005 to 0.01% boron; and the balance iron, and wherein the alloy may be thermomechanically treated to enhance physical and mechanical properties.

  3. Practical handbook of stainless steels and nickel alloys

    SciTech Connect

    Lamb, S.

    1999-07-01

    This new handbook is an up-to-date technical guide to the grades, properties, fabrication characteristics, and applications of stainless steels and nickel alloys. The individual chapters were written by industry experts and focus on the key properties and alloy characteristics important in material selection and specification as well as the practical factors that influence the development and application of these materials. The contents include: alloy grades and their welding and fabrication characteristics and their application; monel metal; iron-based and nickel-based alloys; ferritic, austenitic, superaustenitic, and martensitic stainless steels; hastelloys; alloys 20, G, and 825; AOD and new refining technology; duplex stainless steels; 6-Mo alloys; corrosion-resistant castings; specification cross-reference tables; trade names; hardness conversions; list of common abbreviations.

  4. Materials data handbook: Stainless steel alloy A-286

    NASA Technical Reports Server (NTRS)

    Muraca, R. F.; Whittick, J. S.

    1972-01-01

    A summary of the materials property information for stainless steel alloy A-286 is presented. The scope of the information includes physical and mechanical properties at cryogenic, ambient, and elevated temperatures. Information on material procurement, metallurgy of the alloy, corrosion, environmental effects, fabrication, and bonding is developed.

  5. Corrosion behavior of stainless steel-zirconium alloy waste forms.

    SciTech Connect

    Abraham, D. P.

    1999-01-13

    Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposal of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The baseline waste form for spent fuels from the EBR-II reactor is a stainless steel-15 wt.% zirconium (SS-15Zr) alloy. This article briefly reviews the microstructure of various SS-Zr waste form alloys and presents results of immersion corrosion and electrochemical corrosion tests performed on these alloys. The electrochemical tests show that the corrosion behavior of SS-Zr alloys is comparable to those of other alloys being considered for the Yucca Mountain geologic repository. The immersion tests demonstrate that the SS-Zr alloys are resistant to selective leaching of fission product elements and, hence, suitable as candidates for high-level nuclear waste forms.

  6. Laves intermetallics in stainless steel-zirconium alloys

    SciTech Connect

    Abraham, D.P.; McDeavitt, S.M.; Richardson, J.W. Jr.

    1997-05-01

    Laves intermetallics have a significant effect on properties of metal waste forms being developed at Argonne National Laboratory. These waste forms are stainless steel-zirconium alloys that will contain radioactive metal isotopes isolated from spent nuclear fuel by electrometallurgical treatment. The baseline waste form composition for stainless steel-clad fuels is stainless steel-15 wt.% zirconium (SS-15Zr). This article presents results of neutron diffraction measurements, heat-treatment studies and mechanical testing on SS-15Zr alloys. The Laves intermetallics in these alloys, labeled Zr(Fe,Cr,Ni){sub 2+x}, have both C36 and C15 crystal structures. A fraction of these intermetallics transform into (Fe,Cr,Ni){sub 23}Zr{sub 6} during high-temperature annealing; the authors have proposed a mechanism for this transformation. The SS-15Zr alloys show virtually no elongation in uniaxial tension, but exhibit good strength and ductility in compression tests. This article also presents neutron diffraction and microstructural data for a stainless steel-42 wt.% zirconium (SS-42Zr) alloy.

  7. Milling and Drilling Evaluation of Stainless Steel Powder Metallurgy Alloys

    SciTech Connect

    Lazarus, L.J.

    2001-12-10

    Near-net-shape components can be made with powder metallurgy (PM) processes. Only secondary operations such as milling and drilling are required to complete these components. In the past and currently production components are made from powder metallurgy (PM) stainless steel alloys. process engineers are unfamiliar with the difference in machining properties of wrought versus PM alloys and have had to make parts to develop the machining parameters. Design engineers are not generally aware that some PM alloy variations can be furnished with machining additives that greatly increase tool life. Specimens from a MANTEC PM alloy property study were made available. This study was undertaken to determine the machining properties of a number of stainless steel wrought and PM alloys under the same conditions so that comparisons of their machining properties could be made and relative tool life determined.

  8. Method of polishing nickel-base alloys and stainless steels

    DOEpatents

    Steeves, Arthur F.; Buono, Donald P.

    1981-01-01

    A chemical attack polish and polishing procedure for use on metal surfaces such as nickel base alloys and stainless steels. The chemical attack polish comprises Fe(NO.sub.3).sub.3, concentrated CH.sub.3 COOH, concentrated H.sub.2 SO.sub.4 and H.sub.2 O. The polishing procedure includes saturating a polishing cloth with the chemical attack polish and submicron abrasive particles and buffing the metal surface.

  9. Attack polish for nickel-base alloys and stainless steels

    DOEpatents

    Steeves, Arthur F.; Buono, Donald P.

    1983-01-01

    A chemical attack polish and polishing procedure for use on metal surfaces such as nickel base alloys and stainless steels. The chemical attack polish comprises Fe(NO.sub.3).sub.3, concentrated CH.sub.3 COOH, concentrated H.sub.2 SO.sub.4 and H.sub.2 O. The polishing procedure includes saturating a polishing cloth with the chemical attack polish and submicron abrasive particles and buffing the metal surface.

  10. Attack polish for nickel-base alloys and stainless steels

    DOEpatents

    Not Available

    1980-05-28

    A chemical attack polish and polishing procedure for use on metal surfaces such as nickel base alloys and stainless steels is described. The chemical attack polich comprises FeNO/sub 3/, concentrated CH/sub 3/COOH, concentrated H/sub 2/SO/sub 4/ and H/sub 2/O. The polishing procedure includes saturating a polishing cloth with the chemical attack polish and submicron abrasive particles and buffing the metal surface.

  11. Alternative to Nitric Acid for Passivation of Stainless Steel Alloys

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie L.; Kolody, Mark; Curran, Jerry

    2013-01-01

    Corrosion is an extensive problem that affects the Department of Defense (DoD) and National Aeronautics and Space Administration (NASA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. Consequently, it is vital to reduce corrosion costs and risks in a sustainable manner. The DoD and NASA have numerous structures and equipment that are fabricated from stainless steel. The standard practice for protection of stainless steel is a process called passivation. Typical passivation procedures call for the use of nitric acid; however, there are a number of environmental, worker safety, and operational issues associated with its use. Citric acid offers a variety of benefits including increased safety for personnel, reduced environmental impact, and reduced operational cost. DoD and NASA agreed to collaborate to validate citric acid as an acceptable passivating agent for stainless steel. This paper details our investigation of prior work developing the citric acid passivation process, development of the test plan, optimization of the process for specific stainless steel alloys, ongoing and planned testing to elucidate the process' resistance to corrosion in comparison to nitric acid, and preliminary results.

  12. Galvanic corrosion between dental precious alloys and magnetic stainless steels used for dental magnetic attachments.

    PubMed

    Takahashi, Noriko; Takada, Yukyo; Okuno, Osamu

    2008-03-01

    In this study, we examined the corrosion behavior of dental precious alloys and magnetic stainless steels, namely SUS 444, SUS XM27, and SUS 447J1, used for dental magnetic attachments. Their galvanic corrosion behavior was evaluated from the viewpoint of corrosion potentials when they were in contact with each other. Rest potentials of the precious alloys were constantly higher than those of magnetic stainless steels. Since most gold alloys raised the corrosion potential more significantly than silver alloys did, silver alloys seemed to be better suited than gold alloys for combination with magnetic stainless steels. However, all corrosion potential values were sufficiently lower than the breakdown potentials of the stainless steels and existed within their passive regions. Based on the findings of this study, SUS XM27 and SUS 447J1--which exhibited higher breakdown potentials than SUS 444--emerged as the preferred choices for combination with gold alloys.

  13. Precipitation sequence in niobium-alloyed ferritic stainless steel

    NASA Astrophysics Data System (ADS)

    Fujita, Nobuhiro; Bhadeshia, H. K. D. H.; Kikuchi, Masao

    2004-03-01

    Niobium is an important alloying element in the design of heat-resistant ferritic stainless steels for automotive exhaust systems. When in solid solution, it improves both the high temperature strength and the resistance to thermal fatigue. However, it also forms several kinds of precipitates during service. These reactions have been modelled, taking into account the multicomponent nature of the diffusion process and allowing for capillarity effects. It has been possible to estimate not only the volume fractions but also the particle sizes for Fe2Nb (Laves phase) and Fe3Nb3C (M6C) carbide in a 19Cr-0.8Nb steel, with good agreement against experimental data.

  14. Crack initiation mechanisms in IASCC of stainless steel alloys

    SciTech Connect

    Cookson, J.M.; Was, G.S.; Andresen, P.L.

    1995-12-31

    An abnormally high oxygen concentration was recently discovered in a high purity stainless steel alloy widely used in IASCC studies. This led to an investigation into the role of oxygen on the initiation of intergranular cracking in irradiated samples in high temperature water. The concentration of oxygen in the alloys correlated with the number of cracks initiated in the proton irradiated region of samples strained in water containing 0.5 {micro}S/cm H{sub 2}SO{sub 4} at 288 C. This suggests that the presence of oxygen, in the form of spinel oxide particles, can lead to a substantial increase in the likelihood of crack initiation. This effect is only observed in irradiated samples strained in water, not in either unirradiated (non-sensitized) samples strained in water or irradiated samples strained in argon This paper examines the possible role of oxides in promoting crack initiation and the implications for IASCC.

  15. Stablization of Nanotwinned Microstructures in Stainless Steels Through Alloying and Microstructural Design

    DTIC Science & Technology

    2013-08-23

    stable nanotwinned microstructure---high-temperature strength. The long - term goal of this effort is to develop austenitic stainless steels capable of...microstructures. The long - term alloy design strategy focuses on microalloying additions to 1) reduce the stacking fault energy (SFE), enhance twinning formation...15. SUBJECT TERMS materials design, stainless steels , plastic deformation by twinning, computational materials science, experimental characterization

  16. Laser beam surface melting of high alloy austenitic stainless steel

    SciTech Connect

    Woollin, P.

    1996-12-31

    The welding of high alloy austenitic stainless steels is generally accompanied by a substantial reduction in pitting corrosion resistance relative to the parent, due to microsegregation of Mo and Cr. This prevents the exploitation of the full potential of these steels. Processing to achieve remelting and rapid solidification offers a means of reducing microsegregation levels and improving corrosion resistance. Surface melting of parent UNS S31254 steel by laser beam has been demonstrated as a successful means of producing fine, as-solidified structures with pitting resistance similar to that of the parent, provided that an appropriate minimum beam travel speed is exceeded. The use of N{sub 2} laser trail gas increased the pitting resistance of the surface melted layer. Application of the technique to gas tungsten arc (GTA) melt runs has shown the ability to raise the pitting resistance significantly. Indeed, the use of optimized beam conditions, N{sub 2} trail gas and appropriate surface preparation prior to laser treatment increased the pitting resistance of GTA melt runs to a level approaching that of the parent material.

  17. Nanosized controlled surface pretreatment of biometallic alloy 316L stainless steel.

    PubMed

    Abdel-Fattah, Tarek M; Loftis, Derek; Mahapatro, Anil

    2011-12-01

    Stainless steel (AISI 316L) is a medical grade stainless steel alloy used extensively in medical devices and in the biomedical field. 316L stainless steel was successfully electropolished via an ecologically friendly and biocompatible ionic liquid (IL) medium based on Vitamin B4 (NB4) and resulting in nanosized surface roughness and topography. Voltammetry and chronoamperometry tests determined optimum polishing conditions for the stainless steel alloy while atomic force microscopy (AFM) and scanning electron microscopy (SEM) provided surface morphology comparisons to benchmark success of each electropolishing condition. Energy dispersive X-ray analysis (EDX) combined with SEM revealed significantly smoother surfaces for each alloy surface while indicating that the constituent metals comprising each alloy effectively electropolished at uniform rates.

  18. Copper modified austenitic stainless steel alloys with improved high temperature creep resistance

    DOEpatents

    Swindeman, R.W.; Maziasz, P.J.

    1987-04-28

    An improved austenitic stainless steel that incorporates copper into a base Fe-Ni-Cr alloy having minor alloying substituents of Mo, Mn, Si, T, Nb, V, C, N, P, B which exhibits significant improvement in high temperature creep resistance over previous steels. 3 figs.

  19. The success and limitations of high alloy stainless steels in seawater service

    SciTech Connect

    Gallagher, P.; Malpas, R.E. )

    1989-01-01

    The performance of high alloy stainless steels has been determined in chlorinated natural seawater in large scale and prototype seawater handling systems consisting of pumps, pipework and valves at ambient North Sea temperatures. In addition the influence of temperature on the corrosion characteristics of these alloys has been investigated. The results show that austenitic stainless steels with minimum molybdenum and nitrogen contents of 6% and 0.2% respectively and high alloy duplex stainless steels with minimum compositions of 25% Cr, 3% Mo and 0.15% N can be successfully used for the fabrication of seawater systems handling North Sea ambient or heated seawater. These alloys have some limitations, however, in areas of heat transfer, particularly where air spaces are present in a system; where dissimilar metal crevices are present and at positions where fretting can occur.

  20. Experimental and Theoretical Investigations of Hot Isostatically Pressed-Produced Stainless Steel/High Alloy Tool Steel Compound Materials

    NASA Astrophysics Data System (ADS)

    Lindwall, Greta; Flyg, Jesper; Frisk, Karin; Sandberg, Odd

    2011-05-01

    Consolidation of tool steel powders and simultaneous joining to a stainless 316L steel are performed by hot isostatic pressing (HIP). Two tool steel grades are considered: a high vanadium alloyed carbon tool steel, and a high vanadium and chromium alloyed nitrogen tool steel. The boundary layer arising during diffusion bonding is in focus and, in particular, the diffusion of carbon and nitrogen over the joint. Measurements of the elemental concentration profiles and corrosion tests by the double loop-electrochemical potentiokinetic reactivation (DL-EPR) method are performed. Comparative calculations with the DICTRA software are performed and are found to be in agreement with the experimental results. It is found that the carbon tool steel grade has a more critical influence on the corrosion resistance of the stainless 316L steel in comparison to the nitrogen tool steel grade.

  1. Electrochemical Corrosion Testing of Borated Stainless Steel Alloys

    SciTech Connect

    lister, tedd e; Mizia, Ronald E

    2007-05-01

    The Department of Energy Office of Civilian Radioactive Waste Management has specified borated stainless steel manufactured to the requirements of ASTM A 887-89, Grade A, UNS S30464, to be the material used for the fabrication of the fuel basket internals of the preliminary transportation, aging, and disposal canister system preliminary design. The long-term corrosion resistance performance of this class of borated materials must be verified when exposed to expected YMP repository conditions after a waste package breach. Electrochemical corrosion tests were performed on crevice corrosion coupons of Type 304 B4 and Type 304 B5 borated stainless steels exposed to single postulated in-package chemistry at 60°C. The results show low corrosion rates for the test period

  2. Electrochemical Corrosion Testing of Borated Stainless Steel Alloys

    SciTech Connect

    lister, tedd e; Mizia, Ronald E

    2007-09-01

    The Department of Energy Office of Civilian Radioactive Waste Management has specified borated stainless steel manufactured to the requirements of ASTM A 887-89, Grade A, UNS S30464, to be the material used for the fabrication of the fuel basket internals of the preliminary transportation, aging, and disposal canister system preliminary design. The long-term corrosion resistance performance of this class of borated materials must be verified when exposed to expected YMP repository conditions after a waste package breach. Electrochemical corrosion tests were performed on crevice corrosion coupons of Type 304 B4 and Type 304 B5 borated stainless steels exposed to single postulated in-package chemistry at 60°C. The results show low corrosion rates for the test period

  3. Articles comprising ferritic stainless steels

    SciTech Connect

    Rakowski, James M.

    2016-06-28

    An article of manufacture comprises a ferritic stainless steel that includes a near-surface region depleted of silicon relative to a remainder of the ferritic stainless steel. The article has a reduced tendency to form an electrically resistive silica layer including silicon derived from the steel when the article is subjected to high temperature oxidizing conditions. The ferritic stainless steel is selected from the group comprising AISI Type 430 stainless steel, AISI Type 439 stainless steel, AISI Type 441 stainless steel, AISI Type 444 stainless steel, and E-BRITE.RTM. alloy, also known as UNS 44627 stainless steel. In certain embodiments, the article of manufacture is a fuel cell interconnect for a solid oxide fuel cell.

  4. Effect of Stress Relief Annealing on Microstructure & Mechanical Properties of Welded Joints Between Low Alloy Carbon Steel and Stainless Steel

    NASA Astrophysics Data System (ADS)

    Nivas, R.; Das, G.; Das, S. K.; Mahato, B.; Kumar, S.; Sivaprasad, K.; Singh, P. K.; Ghosh, M.

    2017-01-01

    Two types of welded joints were prepared using low alloy carbon steel and austenitic stainless steel as base materials. In one variety, buttering material and weld metal were Inconel 82. In another type, buttering material and weld metal were Inconel 182. In case of Inconel 82, method of welding was GTAW. For Inconel 182, welding was done by SMAW technique. For one set of each joints after buttering, stress relief annealing was done at 923 K (650 °C) for 90 minutes before further joining with weld metal. Microstructural investigation and sub-size in situ tensile testing in scanning electron microscope were carried out for buttered-welded and buttered-stress relieved-welded specimens. Adjacent to fusion boundary, heat-affected zone of low alloy steel consisted of ferrite-pearlite phase combination. Immediately after fusion boundary in low alloy steel side, there was increase in matrix grain size. Same trend was observed in the region of austenitic stainless steel that was close to fusion boundary between weld metal-stainless steel. Close to interface between low alloy steel-buttering material, the region contained martensite, Type-I boundary and Type-II boundary. Peak hardness was obtained close to fusion boundary between low alloy steel and buttering material. In this respect, a minimum hardness was observed within buttering material. The peak hardness was shifted toward buttering material after stress relief annealing. During tensile testing no deformation occurred within low alloy steel and failure was completely through buttering material. Crack initiated near fusion boundary between low alloy steel-buttering material for welded specimens and the same shifted away from fusion boundary for stress relieved annealed specimens. This observation was at par with the characteristics of microhardness profile. In as welded condition, joints fabricated with Inconel 82 exhibited superior bond strength than the weld produced with Inconel 182. Stress relief annealing

  5. Study made of corrosion resistance of stainless steel and nickel alloys in nuclear reactor superheaters

    NASA Technical Reports Server (NTRS)

    Greenberg, S.; Hart, R. K.; Lee, R. H.; Ruther, W. E.; Schlueter, R. R.

    1967-01-01

    Experiments performed under conditions found in nuclear reactor superheaters determine the corrosion rate of stainless steel and nickel alloys used in them. Electropolishing was the primary surface treatment before the corrosion test. Corrosion is determined by weight loss of specimens after defilming.

  6. Laser Surface Alloying of SUS316 Stainless Steel with Al-Si

    NASA Astrophysics Data System (ADS)

    Zherebtsov, Sergey; Maekawa, Katsuhiro; Hayashi, Terutake; Futakawa, Masatoshi

    The effect of varying temperature of the type 316 stainless steel substrate on the structure and properties of laser alloyed layer was investigated. The material for alloying (Al-Si powder mixture) was placed on the surface of stainless steel substrate by pasting. The surface was scanned by a pulsed Nd: YAG laser beam to achieve surface alloying. The temperature of substrate continuously increased during laser treatment to about 830°C. The microstructure, chemical and phase composition and microhardness of the modified layer were studied then. It has been found that four different types of structure were formed in the alloyed zone depending on the temperature of the substrate. These structures differ from each other in phase composition, microhardness and relation to cracking. Based on the results, optimal parameters for the production of a uniform, crack-free layer with a high hardness were developed.

  7. Industrial Experience on the Caustic Cracking of Stainless Steels and Nickel Alloys - A Review

    SciTech Connect

    Rebak, R B

    2005-10-09

    Caustic environments are present in several industries, from nuclear power generation to the fabrication of alkalis and alumina. The most common material of construction is carbon steel but its application is limited to a maximum temperature of approximately 80 C. The use of Nickel (Ni) alloys is recommended at higher temperatures. Commercially pure Ni is the most resistant material for caustic applications both from the general corrosion and the stress corrosion cracking (SCC) perspectives. Nickel rich alloys also offer a good performance. The most important alloying elements are Ni and chromium (Cr). Molybdenum (Mo) is not a beneficial alloying element and it dissolves preferentially from the alloy in presence of caustic environments. Austenitic stainless steels such as type 304 and 316 seem less resistant to caustic conditions than even plain carbon steel. Experimental evidence shows that the most likely mechanism for SCC is anodic dissolution.

  8. Bactericidal activity of copper and niobium-alloyed austenitic stainless steel.

    PubMed

    Baena, M I; Márquez, M C; Matres, V; Botella, J; Ventosa, A

    2006-12-01

    Biofouling and microbiologically influenced corrosion are processes of material deterioration that originate from the attachment of microorganisms as quickly as the material is immersed in a nonsterile environment. Stainless steels, despite their wide use in different industries and as appliances and implant materials, do not possess inherent antimicrobial properties. Changes in hygiene legislation and increased public awareness of product quality makes it necessary to devise control methods that inhibit biofilm formation or to act at an early stage of the biofouling process and provide the release of antimicrobial compounds on a sustainable basis and at effective level. These antibacterial stainless steels may find a wide range of applications in fields, such as kitchen appliances, medical equipment, home electronics, and tools and hardware. The purpose of this study was to obtain antibacterial stainless steel and thus mitigate the microbial colonization and bacterial infection. Copper is known as an antibacterial agent; in contrast, niobium has been demonstrated to improve the antimicrobial effect of copper by stimulating the formation of precipitated copper particles and its distribution in the matrix of the stainless steel. Thus, we obtained slides of 3.8% copper and 0.1% niobium alloyed stainless steel; subjected them to three different heat treatment protocols (550 degrees C, 700 degrees C, and 800 degrees C for 100, 200, 300, and 400 hours); and determined their antimicrobial activities by using different initial bacterial cell densities and suspending solutions to apply the bacteria to the stainless steels. The bacterial strain used in these experiments was Escherichia coli CCM 4517. The best antimicrobial effects were observed in the slides of stainless steel treated at 700 degrees C and 800 degrees C using an initial cell density of approximately 10(5) cells ml(-1) and phosphate-buffered saline as the solution in which the bacteria came into contact with

  9. Development of a Nitrogen-Modified Stainless-Steel Hardfacing Alloy

    NASA Astrophysics Data System (ADS)

    Smith, Ryan Thomas

    A 2nd generation hardfacing alloy, Nitromaxx, has been designed though an integrated approach of chemical modification, characterization, and testing. Nitromaxx is a stainless-steel alloy modified with 0.5wt% nitrogen which has improved elevated temperature properties and wear performance. This is achieved by changing both the microstructure phase balance and inherent deformation characteristics of the metal. The alloy is fabricated by a powder metallurgy-hot isostatic pressing (PM-HIP) method, rather than traditional cladding methods. This allows for alloy property modification by equilibrium heat treatment while eliminating significant fabrication defects, so that component life is extended wear and galling performance is improved. The design approach involved extensive characterization of severely worn and galled surfaces of the 1st generation of hardfacing alloys. Observation of samples after galling testing showed highly inhomogeneous deformation in regions of the gall scar, leading to the design hypothesis that strain-localization is a controlling mechanism in severe wear of stainless-steels. Additionally, the presence and subsequent loss was investigated and correlated microstructurally to the transition to poor galling behavior in the existing stainless steel hardfacing NOREM02. This provided new insight and identification of key microstructural and mechanical properties that improve galling performance: 1) increased strain-hardening rate in the metal matrix at elevated temperature, 2) increased yield strength in the matrix leading to higher hardness, and 3) increased volume fraction of hard, non-deforming phases. All of these alloy design goals can be realized by the addition of nitrogen, which 1) at high concentration is shown to lower the stacking fault energy in the stainless steel matrix, 2) increases interstitial matrix strengthening, and 3) increases the volume fraction of nitride phases. These observations have been confirmed qualitatively and

  10. Nondestructive inspection assessment of eddy current and electrochemical analysis to separate inconel and stainless steel alloys

    SciTech Connect

    Moore, D.G.; Sorensen, N.R.

    1998-02-01

    This report presents a nondestructive inspection assessment of eddy current and electrochemical analysis to separate inconel alloys from stainless steel alloys as well as an evaluation of cleaning techniques to remove a thermal oxide layer on aircraft exhaust components. The results of this assessment are presented in terms of how effective each technique classifies a known exhaust material. Results indicate that either inspection technique can separate inconel and stainless steel alloys. Based on the experiments conducted, the electrochemical spot test is the optimum for use by airframe and powerplant mechanics. A spot test procedure is proposed for incorporation into the Federal Aviation Administration Advisory Circular 65-9A Airframe & Powerplant Mechanic - General Handbook. 3 refs., 70 figs., 7 tabs.

  11. 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.

  12. Application of nitrogen-alloyed martensitic stainless steels in the aviation industry

    SciTech Connect

    Stein, G.; Kirschner, W.; Lueg, J.

    1997-12-31

    Nitrogen in stainless martensitic steels has a beneficial influence on the mechanical as well as on the chemical properties. However the effect of nitrogen is limited due to the rather low solubility of this element. A special alloy development in combination with a pressurized melting technique lead to distinctly higher nitrogen contents. Stainless martensitic steels containing high nitrogen contents are manufactured by VSG today on an industrial scale using the PESR-process (Pressurized Electroslag Remelting). Depending on special applications these steels are available with different chemical analysis under the trademark CRONIDUR. The basic composition of all CRONIDUR-alloys consists of about 15% Chromium, 1% Molybdenum, 0.15 to 0.35% Carbon and 0.20 to 0.40% Nitrogen. The combination of Cr + Mo + N leads to a superior corrosion resistance of these HNS-steels (HNS: High Nitrogen Steels) in comparison to similar carbon based alloys. Focused on applications with a required minimum hardness of 58 HRC, like stainless bearings or screw shafts, the C+N-content is tuned between 0.60 and 0.80% (Brand: CRONIDUR 30). Additions of max. 0.3% Vanadium and 0.1% Niobium qualifies the brand CRONIDUR 20 for enhanced temperature applications like turbine disks or blades.

  13. Copper-Nickel Cladding on Stainless Steel

    DTIC Science & Technology

    2005-07-01

    steel,. Monel (65Ni/35Cu) alloy consumables should be used as they can tolerate more iron dilution from the steel than the 70-30 copper-nickel alloy ...Cooper Alloys , 400 , K-500 Stainless Steel - Tyles 302, 304, 321, 347 N ickel 200 Silver Braze Alloys Nickel-Chromium Alloy 600 Nickel-Aluminum Bronze 70...cladding of austenitic stainless steels may also offer some ballistic, non-magnetic, and electromagnetic signature advantages over current hull alloys and

  14. Surface microstructures and antimicrobial properties of copper plasma alloyed stainless steel

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangyu; Huang, Xiaobo; Jiang, Li; Ma, Yong; Fan, Ailan; Tang, Bin

    2011-12-01

    Bacterial adhesion to stainless steel surfaces is one of the major reason causing the cross-contamination and infection in many practical applications. An approach to solve this problem is to enhance the antibacterial properties on the surface of stainless steel. In this paper, novel antibacterial stainless steel surfaces with different copper content have been prepared by a plasma surface alloying technique at various gas pressures. The microstructure of the alloyed surfaces was investigated using glow discharge optical emission spectroscopy (GDOES) and scanning electron microscopy (SEM). The viability of bacteria attached to the antibacterial surfaces was tested using the spread plate method. The antibacterial mechanism of the alloyed surfaces was studied by X-ray photoelectron spectroscopy (XPS). The results indicate that gas pressure has a great influence on the surface elements concentration and the depth of the alloyed layer. The maximum copper concentration in the alloyed surface obtained at the gas pressure of 60 Pa is about 7.1 wt.%. This alloyed surface exhibited very strong antibacterial ability, and an effective reduction of 98% of Escherichia coli (E. coli) within 1 h was achieved by contact with the alloyed surface. The maximum thickness of the copper alloyed layer obtained at 45 Pa is about 6.5 μm. Although the rate of reduction for E. coli of this alloyed surface was slower than that of the alloyed surface with the copper content about 7.1 wt.% over the first 3 h, few were able to survive more than 12 h and the reduction reached over 99.9%. The XPS analysis results indicated that the copper ions were released when the copper alloyed stainless steel in contact with bacterial solution, which is an important factor for killing bacteria. Based on an overall consideration of bacterial killing rate and durability, the alloyed surface with the copper content of 2.5 wt.% and the thickness of about 6.5 μm obtained at the gas pressure of 45 Pa is expected

  15. M551 metals melting experiment. [space manufacturing of aluminum alloys, tantalum alloys, stainless steels

    NASA Technical Reports Server (NTRS)

    Li, C. H.; Busch, G.; Creter, C.

    1976-01-01

    The Metals Melting Skylab Experiment consisted of selectively melting, in sequence, three rotating discs made of aluminum alloy, stainless steel, and tantalum alloy. For comparison, three other discs of the same three materials were similarly melted or welded on the ground. The power source of the melting was an electron beam unit. Results are presented which support the concept that the major difference between ground base and Skylab samples (i.e., large elongated grains in ground base samples versus nearly equiaxed and equal sized grains in Skylab samples) can be explained on the basis of constitutional supercooling, and not on the basis of surface phenomena. Microstructural observations on the weld samples and present explanations for some of these observations are examined. In particular, ripples and their implications to weld solidification were studied. Evidence of pronounced copper segregation in the Skylab A1 weld samples, and the tantalum samples studied, indicates a weld microhardness (and hence strength) that is uniformly higher than the ground base results, which is in agreement with previous predictions. Photographs are shown of the microstructure of the various alloys.

  16. Austenitic stainless steels and high strength copper alloys for fusion components

    NASA Astrophysics Data System (ADS)

    Rowcliffe, A. F.; Zinkle, S. J.; Stubbins, J. F.; Edwards, D. J.; Alexander, D. J.

    1998-10-01

    An austenitic stainless steel (316LN), an oxide-dispersion-strengthened copper alloy (GlidCop Al25), and a precipitation-hardened copper alloy (Cu-Cr-Zr) are the primary structural materials for the ITER first wall/blanket and divertor systems. While there is a long experience of operating 316LN stainless steel in nuclear environments, there is no prior experience with the copper alloys in neutron environments. The ITER first wall (FW) consists of a stainless steel shield with a copper alloy heat sink bonded by hot isostatic pressing (HIP). The introduction of bi-layer structural material represents a new materials engineering challenge; the behavior of the bi-layer is determined by the properties of the individual components and by the nature of the bond interface. The development of the radiation damage microstructure in both classes of materials is summarized and the effects of radiation on deformation and fracture behavior are considered. The initial data on the mechanical testing of bi-layers indicate that the effectiveness of GlidCop Al25 as a FW heat sink material is compromised by its strongly anisotropic fracture toughness and poor resistance to crack growth in a direction parallel to the bi-layer interface.

  17. Microstructural development of diffusion-brazed austenitic stainless steel to magnesium alloy using a nickel interlayer

    SciTech Connect

    Elthalabawy, Waled M.; Khan, Tahir I.

    2010-07-15

    The differences in physical and metallurgical properties of stainless steels and magnesium alloys make them difficult to join using conventional fusion welding processes. Therefore, the diffusion brazing of 316L steel to magnesium alloy (AZ31) was performed using a double stage bonding process. To join these dissimilar alloys, the solid-state diffusion bonding of 316L steel to a Ni interlayer was carried out at 900 deg. C followed by diffusion brazing to AZ31 at 510 deg. C. Metallographic and compositional analyses show that a metallurgical bond was achieved with a shear strength of 54 MPa. However, during the diffusion brazing stage B{sub 2} intermetallic compounds form within the joint and these intermetallics are pushed ahead of the solid/liquid interface during isothermal solidification of the joint. These intermetallics had a detrimental effect on joint strengths when the joint was held at the diffusion brazing temperature for longer than 20 min.

  18. 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.

  19. Comparative MRI compatibility of 316 L stainless steel alloy and nickel-titanium alloy stents.

    PubMed

    Holton, Andrea; Walsh, Edward; Anayiotos, Andreas; Pohost, Gerald; Venugopalan, Ramakrishna

    2002-01-01

    The initial success of coronary stenting is leading to a proliferation in peripheral stenting. A significant portion of the stents used in a clinical setting are made of 316 low carbon stainless steel (SS). Other alloys that have been used for stent manufacture include tantalum, MP35N, and nickel-titanium (NiTi). The ferromagnetic properties of SS cause the production of artifacts in magnetic resonance imaging (MRI). The NiTi alloys, in addition to being known for their shape memory or superelastic properties, have been shown to exhibit reduced interference in MRI. Thus, the objective of this study was to determine the comparative MRI compatibility of SS and NiTi stents. Both gradient echo and spin-echo images were obtained at 1.5 and 4.1 T field strengths. The imaging of stents of identical geometry but differing compositions permitted the quantification of artifacts produced due to device composition by normalizing the radio frequency shielding effects. These images were analyzed for magnitude and spatial extent of signal loss within the lumen and outside the stent. B1 mapping was used to quantify the attenuation throughout the image. The SS stent caused significant signal loss and did not allow for visibility of the lumen. However, the NiTi stent caused only minor artifacting and even allowed for visualization of the signal from within the lumen. In addition, adjustments to the flip angle of standard imaging protocols were shown to improve the quality of signal from within the lumen.

  20. Study of electroless Ni-W-P alloy coating on martensitic stainless steel

    NASA Astrophysics Data System (ADS)

    Nikitasari, Arini; Mabruri, Efendi

    2016-04-01

    Electroless nickel phospor (Ni-P) is widely used in many industries due to their corrosion and wear resistance, coating uniformity, and ability to coat non-conductive surfaces. The unique properties of tungsten such as high hardness, higher melting point, lower coefficient of linear thermal expansion, and high tensile strength have created a lot of interest in developing ternary Ni-W-P alloys. This article presents the study of electroless Ni-W-P alloys coating using acid or alkaline bath on martensitic stainless steel. Nickel sulfate and sodium tungstate were used as nickel and tungsten sources, respectively, and sodium hypophosphite was used as a reducing agent. Acid or alkaline bath refer to bath pH condition was adjusted by adding sulfuric acid. Martensitic stainless steel was immersed in Ni-W-P bath for 15, 30, and 60 minutes. The substrate of martensitic stainless steel was subjected to pre-treatment (polishing and cleaning) and activation prior to electroless plating. The plating characteristics were investigated for concentration ratio of nickel and hypophosphite (1:3), sodium tungstate concentration 0,1 M, immersion time (15 min, 30 min, 60 min), and bath condition (acid, alkaline). The electroless Ni-W-P plating was heat treated at 400°C for 1 hour. Deposits were characterized using scanning electron microscope (SEM) and corrosion measurement system (CMS).

  1. Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating

    DOEpatents

    Howard, Stanley R.; Korinko, Paul S.

    2008-05-27

    A method of fabricating a heat exchanger includes brush electroplating plated layers for a brazing alloy onto a stainless steel tube in thin layers, over a nickel strike having a 1.3 .mu.m thickness. The resultant Au-18 In composition may be applied as a first layer of indium, 1.47 .mu.m thick, and a second layer of gold, 2.54 .mu.m thick. The order of plating helps control brazing erosion. Excessive amounts of brazing material are avoided by controlling the electroplating process. The reticulated copper foam rings are interference fit to the stainless steel tube, and in contact with the plated layers. The copper foam rings, the plated layers for brazing alloy, and the stainless steel tube are heated and cooled in a vacuum furnace at controlled rates, forming a bond of the copper foam rings to the stainless steel tube that improves heat transfer between the tube and the copper foam.

  2. Influence of nitrogen alloying on hydrogen embrittlement in AISI 304-type stainless steels

    NASA Astrophysics Data System (ADS)

    Hannula, Simo-Pekka; Hänninen, Hannu; Tähtinen, Seppo

    1984-12-01

    Hydrogen embrittlement of AISI 304-type austenitic stainless steels has been studied with special emphasis on the effects of the nitrogen content of the steels. Hydrogen charging was found to degrade the mechanical properties of all the steels studied, as measured by a tensile test. The fracture surfaces of hydrogen charged specimens were brittle cleavage-like whereas the uncharged specimens showed ductile, dimpled fracture. In sensitized materials transgranular cleavage mode of fracture was replaced by an intergranular mode of fracture and the losses of mechanical properties were higher. Nitrogen alloying decreased the hydrogen-induced losses of mechanical properties by increasing the stability of austenite. In sensitized steels the stability of austenite and nitrogen content were found to have only a minor effect on hydrogen embrittlement, except when sensitization had caused α'-martensite transformation at the grain boundaries.

  3. Alloy 31, a new 6 moly stainless steel with improved corrosion resistance in seawater

    SciTech Connect

    Jasner, M.; Heubner, U.

    1995-10-01

    Alloy 31--UNS N08031--31Ni-27Cr-6.5Mo-1.2Cu-0.2N-balance iron--is an advanced 6 Mo stainless steel with increased chromium and nickel, contents for seawater service. In hot seawater the pitting potential of alloy 31 remains high up to 90 C (194 F). Investigations of resistance to crevice corrosion in real piping systems in natural seawater, both North Sea and Baltic Sea, show that the threshold conditions for alloy 31 in chlorinated seawater (North Sea) are at 40 C and 1 ppm chlorine well superior to the 6 Mo stainless grades being currently in use. In addition, alloy 31 shows an excellent resistance to corrosion versus both hot reducing media (e.g. H{sub 2}SO{sub 4}) and hot oxidizing media (e.g. HNO{sub 3}). The combination of high resistance to localized corrosion vs. hot chloride-bearing cooling waters including seawater and aggressive oxidizing and reducing hot corrosive media is a unique feature of alloy 31. Alloy 31 is recommended for the construction of heat exchangers, process coolers and piping systems. The material is supplied in a number of semifinished products such as seamless and welded pipes, fittings, flanges, forged bars, plate, sheet, strip, wire and prefabricated piping systems.

  4. Microstructure-fracture toughness relationship of vanadium alloy/stainless steel brazed joints

    NASA Astrophysics Data System (ADS)

    Gan, Y. X.; Aglan, H. A.; Steward, R. V.; Chin, B. A.; Grossbeck, M. L.

    2001-11-01

    In this work, brazing V-5Ti-5Cr to 304 stainless steel (SS 304) using Au-18Ni alloy as filler material was conducted under high vacuum condition. Sessile drop technique was used to determine the wettability of filler alloy to the stainless steel and the vanadium alloy substrates upon which the relationship between the contact angles with time was obtained. Tensile tests were performed on unnotched and notched specimens to demonstrate the overloading behavior and the fracture toughness of the base materials and the brazed joint. Fracture surface was examined for both the V-5Ti-5Cr and the joint to identify the failure mechanisms under static loadings. It was found that the Au-18Ni filler material exhibited good wettability with the SS 304 and V-5Ti-5Cr. The ultimate tensile strength of the brazed joint reached 245 MPa. The strain to failure was about 1.3%. Young's modulus was about 351 GPa. The fracture toughness ( KIc) of this joint was 19.1 MPa √ m. The fracture surface of the joint showed well brazed area with good wettability and proper amount of residual filler material which came from the solidification of residual liquid filler alloy of Au-Ni. The failure of the joint occurred along the interface of the vanadium/filler under static load.

  5. Study of austenitic stainless steel welded with low alloy steel filler metal. [tensile and impact strength tests

    NASA Technical Reports Server (NTRS)

    Burns, F. A.; Dyke, R. A., Jr.

    1979-01-01

    The tensile and impact strength properties of 316L stainless steel plate welded with low alloy steel filler metal were determined. Tests were conducted at room temperature and -100 F on standard test specimens machined from as-welded panels of various chemical compositions. No significant differences were found as the result of variations in percentage chemical composition on the impact and tensile test results. The weldments containing lower chromium and nickel as the result of dilution of parent metal from the use of the low alloy steel filler metal corroded more severely in a marine environment. The use of a protective finish, i.e., a nitrile-based paint containing aluminum powder, prevented the corrosive attack.

  6. Chemical elements diffusion in the stainless steel components brazed with Cu-Ag alloy

    NASA Astrophysics Data System (ADS)

    Voiculescu, I.; Geanta, V.; Vasile, I. M.; Binchiciu, E. F.; Winestoock, R.

    2016-06-01

    The paper presents the study of diffusion of chemical elements through a brazing joint, between two thin components (0.5mm) made of stainless steel 304. An experimental brazing filler material has been used for brazing stainless steel component and then the diffusion phenomenon has been studied, in terms of chemical element displacement from the brazed separation interface. The filler material is in the form of a metal rod coated with ceramic slurry mixture of minerals, containing precursors and metallic powders, which can contribute to the formation of deposit brazed. In determining the distance of diffusion of chemical elements, on both sides of the fusion line, were performed measurements of the chemical composition using electron microscopy SEM and EDX spectrometry. Metallographic analysis of cross sections was performed with the aim of highlight the microstructural characteristics of brazed joints, for estimate the wetting capacity, adherence of filler metal and highlight any imperfections. Analyzes performed showed the penetration of alloying elements from the solder (Ag, Cu, Zn and Sn) towards the base material (stainless steel), over distances up to 60 microns.

  7. Effect of alloy composition on high-temperature bending fatigue strength of ferritic stainless steels

    NASA Astrophysics Data System (ADS)

    Ahn, Yong-Sik; Song, Jeon-Young

    2011-12-01

    Exhaust manifolds are subjected to an environment in which heating and cooling cycles occur due to the running pattern of automotive engines. This temperature profile results in the repeated bending stress of exhaust pipes. Therefore, among high-temperature characteristics, the bending fatigue strength is an important factor that affects the lifespan of exhaust manifolds. Here, we report on the effect of the alloy composition, namely the weight fraction of the elements Cr, Mo, Nb, and Ti, on the high-temperature bending fatigue strength of the ferritic stainless steel used in exhaust manifolds. Little difference in the tensile strength and bending fatigue strength of the different composition steels was observed below 600 °C, with the exception of the low-Cr steel. However, steels with high Cr, Mo, or Nb fractions showed considerably larger bending fatigue strength at temperatures of 800 °C. After heating, the precipitates from the specimens were extracted electrolytically and analyzed using scanning electron microscopy energy dispersive spectrometry and transmission electron microscopy. Alloying with Cr and Mo was found to increase the bending fatigue strength due to the substitutional solid solution effect, while alloying with Nb enhanced the strength by forming fine intermetallic compounds, including NbC and Fe2Nb.

  8. A comparative study of the in vitro corrosion behavior and cytotoxicity of a superferritic stainless steel, a Ti-13Nb-13Zr alloy, and an austenitic stainless steel in Hank's solution.

    PubMed

    Assis, S L; Rogero, S O; Antunes, R A; Padilha, A F; Costa, I

    2005-04-01

    In this study, the in vitro corrosion resistance of a superferritic stainless steel in naturally aerated Hank's solution at 37 degrees C has been determined to evaluate the steel for use as a biomaterial. The potentiodynamic polarization method and electrochemical impedance spectroscopy (EIS) were used to determine the corrosion resistance. The polarization results showed very low current densities at the corrosion potential and electrochemical behavior typical of passive metals. At potentials above 0.75 V (SCE), and up to that of the oxygen evolution reaction, the superferritic steel exhibited transpassive behavior followed by secondary passivation. The superferritic stainless steel exhibited high pitting resistance in Hank's solution. This steel did not reveal pits even after polarization to 3000 mV (SCE). The EIS results indicated high impedance values at low frequencies, supporting the results obtained from the polarization measurements. The results obtained for the superferritic steel have been compared with those of the Ti-13Nb-13Zr alloy and an austenitic stainless steel, as Ti alloys are well known for their high corrosion resistance and biocompatibility, and the austenitic stainless steel is widely used as an implant material. The cytotoxicity tests indicated that the superferritic steel, the austenitic steel, and the Ti-13Nb-13Zr alloy were not toxic. Based on corrosion resistance and cytotoxicity results, the superferritic stainless steel can be considered as a potential biomaterial.

  9. Initial bacterial deposition on bare and zeolite-coated aluminum alloy and stainless steel.

    PubMed

    Chen, Gexin; Beving, Derek E; Bedi, Rajwant S; Yan, Yushan S; Walker, Sharon L

    2009-02-03

    In this study, the impact of zeolite thin film coatings on bacterial deposition and "biofouling" of surfaces has been investigated in an aqueous environment. The synthesis of two types of zeolite coatings, ZSM-5 coated on aluminum alloy and zeolite A coated on stainless steel, and the characterization of the coated and bare metal surfaces are described. The extent of cell deposition onto the bare and zeolite-coated aluminum alloy and stainless steel surfaces is investigated in a parallel plate flow chamber system under a laminar flow conditions. The initial rates of bacterial transfer to the various surfaces are compared by utilizing a marine bacterium, Halomonas pacifica g, under a range of ionic strength conditions. H. pacifica g deposited onto bare metal surfaces to a greater extent as compared with cells deposited onto the zeolite coatings. The surface properties found to have the most notable effect on attachment are the electrokinetic and hydrophobicity properties of the metal and zeolite-coated surfaces. These results suggest that a combination of two chemical mechanisms-hydrophobic and electrostatic interactions-contribute to the antifouling nature of the zeolite surface. Additional observations on the relative role of the hydrodynamic and physical phenomena are also discussed.

  10. Alloying effect of Ni and Cr on irradiated microstructural evolution of type 304 stainless steels

    NASA Astrophysics Data System (ADS)

    Tan, L.; Busby, J. T.

    2013-11-01

    Life extension of the existing nuclear power plants imposes significant challenges to core structural materials that suffer increased fluences. This paper presents the microstructural evolution of a type 304 stainless steel and its variants alloyed with extra Ni and Cr under neutron irradiation at ˜320 °C for up to 10.2 dpa. Similar to the reported data of type 304 variants, a large amount of Frank loops, ultrafine G-phase/M23C6 particles, and limited amount of cavities were observed in the irradiated samples. The irradiation promoted the growth of pre-existing M23C6 at grain boundaries and resulted in some phase transformation to CrC in the alloy with both extra Ni and Cr. A new type of ultrafine precipitates, possibly (Ti,Cr)N, was observed in all the samples, and its amount was increased by the irradiation. Additionally, α-ferrite was observed in the type 304 steel but not in the Ni or Ni + Cr alloyed variants. The effect of Ni and Cr alloying on the microstructural evolution is discussed.

  11. High Power Laser Welding. [of stainless steel and titanium alloy structures

    NASA Technical Reports Server (NTRS)

    Banas, C. M.

    1972-01-01

    A review of recent developments in high power, carbon dixoide laser welding is presented. Deep penetration welding in stainless steel to 0.5-in. thick, high speed welding in thin gage rimmed steel and gas shielded welding in Ti-6Al-4V alloy are described. The effects of laser power, power density, focusing optics, gas-shielding techniques, material properties and weld speed on weld quality and penetration are discussed. It is shown that laser welding performance in thin materials is comparable to that of electron beams. It is further shown that high quality welds, as evidenced by NDT, mechanical and metal-lographic tests, can be achieved. The potential of the laser for industrial welding applications is indicated.

  12. Investigation of dynamic dry friction between stainless steel and aluminium alloy

    NASA Astrophysics Data System (ADS)

    Keightley, Peter; Winter, Ron; Stirk, Stewart

    2009-06-01

    Previous workers studied dynamic friction by using an impacting copper plate to drive a tapered aluminium alloy plug into a matching hole in a stainless steel outer sheath. The velocity of the back surface of the plug was measured using velocity interferometry. We have performed experiments on a version of this basic configuration that has been enlarged so that the sliding surfaces remain in contact for a longer time than with the original configuration. By comparing our results with computer simulations we conclude that the frictional forces between the inner cone and the steel outer are initially high but decrease significantly as the sliding proceeds. This effect is assumed to result from thermal softening of the material at the sliding interface. The study is supported by metallography of the recovered components.

  13. Supertough Stainless Bearing Steel

    NASA Technical Reports Server (NTRS)

    Olson, Gregory B.

    1995-01-01

    Composition and processing of supertough stainless bearing steel designed with help of computer-aided thermodynamic modeling. Fracture toughness and hardness of steel exceeds those of other bearing steels like 440C stainless bearing steel. Developed for service in fuel and oxidizer turbopumps on Space Shuttle main engine. Because of strength and toughness, also proves useful in other applications like gears and surgical knives.

  14. DC electrodeposition of Mn–Co alloys on stainless steels for SOFC interconnect application

    SciTech Connect

    Wu, Junwei; Jiang, Yinglu; Johnson, Christopher; Liu, Xingbo

    2008-03-01

    High conductivity coatings that resist oxide scale growth and reduce chromium evaporation are needed to make stainless steel interconnect materials viable for long-term stable operation of solid oxide fuel cells (SOFC). Mn1.5Co1.5O4 spinel is one of the most promising coatings for interconnect application because of its high conductivity, good chromium retention capability, as well as good CTE match to ferritic stainless steels. Mn–Co electrodeposition followed by oxidization is potentially a low cost method for fabrication of (Mn,Co)3O4 spinel coatings. This work looks at the co-deposition of Mn–Co alloys for this application. As a guide to optimize the deposition process, characterizations of the cathodic reactions and reaction potentials are done using polarization curves. It was found that as cobalt concentration was varied that the alloy composition became richer in cobalt, indicating that the deposition is regular co-deposition process. It was also found that at 0.05M Co concentration in excess gluconate the Mn–Co alloys composition could be tuned by varying the current density. Coatings with Mn–Co around 1:1 could be obtained at a current density of 250 mA/cm2. However, the higher potential increased hydrogen production making the films more porous. Oxidation of the alloy coatings showed that much of the porosities could be eliminated during oxidation. It was found in a number of samples that fully dense coatings where obtained. The composition of the oxidized coating was found to become enriched in Mn, possibly due to the Mn fast diffusion from the substrate.

  15. Mechanical Property Data 15-5PH (H1025) Stainless Steel Alloy: Hot-Rolled Plate.

    DTIC Science & Technology

    1984-05-01

    fatigue data of unnotched 15 - 5PH stainless steel (H1025, longitudinal). - ~ ~ 5 l5PH Stumhuts Sisa Pmae. Csinuutae M al 110 -- R*01,Kf-3.0 R.T. 100 1.00...40 - 00 Lsishii. of. cruam Figure 2. Axial load fatigue data of notched 15 -SPH stainless steel (H1025, longitudinal). 3 I 20 15 - 5PH Stainless Stee...600 020 ; I I a -ALI AT 4W4C002 100 TO0 6W 30O 0 4 -5 0 07 Ufetime, Nw Cycles Figure 4. Axial load fatigue data of notched 15 - 5PH stainless steel

  16. Study of ultrasonically assisted turning of stainless steel and brass alloys

    NASA Astrophysics Data System (ADS)

    Mahdy, S. M. A.; Gouda, M. A.; Silberschmidt, V. V.

    2013-07-01

    Ultrasonically assisted turning (UAT) is a hybrid machining technique employing high-frequency small-amplitude vibration superimposed on the tool movement during turning. It is superior to conventional turning (CT) with regard to cutting forces, surface quality and machining accuracy. The aim of this study is to investigate the effect of different machining parameters on stainless steel and brass alloys, during both UAT and CT, and evaluate improvements of cutting forces, surface roughness, surface integrity, and machining accuracy. An experimental setup for UAT at Loughborough University was used to accomplish this investigation. This setup used a Picoscope data acquisition add-on with Kistler three-component dynamometer, Seco DNMG cutting inserts were utilized, a surface tester from Taylor Hobson was used to evaluate surface roughness, Alicona Infinite Focus microscope was used to evaluate surface roughness and surface integrity, while Metris CMM with Renishaw probe was employed to evaluate machining accuracy. Cylindrical workpieces of steel and brass alloys were turned under CT and UAT conditions; cutting forces, surface roughness, and machining accuracy produced with both techniques where compared. Significant improvements were noticed in the ultrasonically assisted machining when compared to the CT for both alloys.

  17. 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.

  18. Alloy Shrinkage factors for the investment casting of 17-4PH stainless steel parts

    SciTech Connect

    Sabau, Adrian S; Porter, Wallace D

    2008-01-01

    In this study, the alloy shrinkage factors were obtained for the investment casting of 17-4PH stainless steel parts. For the investment casting process, unfilled wax and fused silica with a zircon prime coat were used for patterns and shell molds, respectively. Dimensions of the die tooling, wax pattern, and casting were measured using a Coordinate Measurement Machine. For all the properties, the experimental data available in the literature did not cover the entire temperature range necessary for process simulation. A comparison between the predicted material property data measured property data is made. It was found that most material properties were accurately predicted over the most of the temperature range of the process. Several assumptions were made in order to obtain a complete set of mechanical property data at high temperatures. Thermal expansion measurements for the 17-4PH alloy were conducted at heating and cooling. As a function of temperature, the thermal expansion for both the alloy and shell mold materials showed different evolution at heating and cooling. Thus, one generic simulation were performed with thermal expansion obtained at heating and another one with thermal expansion obtained at cooling. The alloy dimensions were obtained from numerical simulation results of solidification, heat transfer, and deformation phenomena. As compared with experimental results, the numerical simulation results for the shrinkage factors were slightly over-predicted.

  19. Zr/ZrC modified layer formed on AISI 440B stainless steel by plasma Zr-alloying

    NASA Astrophysics Data System (ADS)

    Shen, H. H.; Liu, L.; Liu, X. Z.; Guo, Q.; Meng, T. X.; Wang, Z. X.; Yang, H. J.; Liu, X. P.

    2016-12-01

    The surface Zr/ZrC gradient alloying layer was prepared by double glow plasma surface alloying technique to increase the surface hardness and wear resistance of AISI 440B stainless steel. The microstructure of the Zr/ZrC alloying layer formed at different alloying temperatures and times as well as its formation mechanism were discussed by using scanning electron microscopy, glow discharge optical emission spectrum, X-ray diffraction and X-ray photoelectron spectroscopy. The adhesive strength, hardness and tribological property of the Zr/ZrC alloying layer were also evaluated in the paper. The alloying surface consists of the Zr-top layer and ZrC-subsurface layer which adheres strongly to the AISI 440B steel substrate. The thickness of the Zr/ZrC alloying layer increases gradually from 16 μm to 23 μm with alloying temperature elevated from 900 °C to 1000 °C. With alloying time from 0.5 h to 4 h, the alloyed depth increases from 3 μm to 30 μm, and the ZrC-rich alloyed thickness vs time is basically parabola at temperature of 1000 °C. Both the hardness and wear resistance of the Zr/ZrC alloying layer obviously increase compared with untreated AISI 440B steel.

  20. Special Features of Fracture of a Solid-State Titanium Alloy - Nickel - Stainless Steel Joint

    NASA Astrophysics Data System (ADS)

    Khazgaliev, R. G.; Mukhametrakhimov, M. Kh.; Imaev, M. F.; Shayakhmetov, R. U.; Mulyukov, R. R.

    2015-10-01

    Microstructure, nanohardness, and special features of fracture of three-phase titanium alloy and stainless steel joint through a nanostructural nickel foil are investigated. Uniformly distributed microcracks are observed in Ti2Ni and TiN3 layers joined at temperatures above T = 700°C, whereas no microcracks are observed in the TiNi layer. This suggests that the reason for microcracking is an anomalously large change in the linear expansion coefficient of the TiNi layer during austenitic-martensitic transformation. Specimens subjected to mechanical tests at T = 20°C are fractured along different layers of the material, namely, in the central part of the specimen they are fractured along the Ti2Тi/TiNi interface, whereas at the edge they are fractured along the TiNi/TiNi3 interface.

  1. Oxidation Characteristics of Fe–18Cr–18Mn-Stainless Steel Alloys

    SciTech Connect

    Rawers, James

    2010-10-01

    Air oxidation studies of Fe-18Cr-18Mn stainless steels were conducted at 525°C, 625°C, and 725°C. Alloys were evaluated with respect to changes in oxidation properties as a result of interstitial additions of nitrogen and carbon and of minor solute additions of silicon, molybdenum, and nickel. Interstitial concentrations possibly had a small, positive effect on oxidation resistance. Minor solute additions significantly improved oxidation resistance but could also reduce interstitial solubility resulting in formation of chromium carbides. Loss of solute chromium resulted in a slight reduction in oxidation protection. Oxidation lasting over 500 hours produced a manganese rich, duplex oxide structure: an outer sesquioxide and an inner spinel oxide.

  2. Comparison of spring characteristics of titanium-molybdenum alloy and stainless steel

    PubMed Central

    Salehi, Anahita; Asatourian, Armen

    2017-01-01

    Background Titanium-molybdenum alloy (TMA) and stainless steel (SS) wires are commonly used in orthodontics as arch-wires for tooth movement. However, plastic deformation phenomenon in these arch-wires seems to be a major concern among orthodontists. This study aimed to compare the mechanical properties of TMA and SS wires with different dimensions. Material and Methods Seventy-two wire samples (36 TMA and 36 SS) of three different sizes (19×25, 17×25 and 16×22) were analyzed in vitro, with 12 samples in each group. Various mechanical properties of the wires, including spring-back, bending moment and stiffness were determined using a universal testing machine. Student’s t-test showed statistically significant differences in the mean values of all the groups. In addition, metallographic comparison of SS and TMA wires was conducted under an optical microscope. Results The degree of stiffness of 16×22-sized SS and TMA springs was found to be 12±2 and 5±0.4, respectively, while the bending moment was estimated to be 1927±352 (gm-mm) and 932±16 (gm-mm), respectively; the spring-back index was determined to be 0.61±0.2 and 0.4±.09, respectively (p<0.001). There were no statistically significant differences in spring-back index in larger dimensions of the wires. Conclusions Systematic analysis indicated that springs made of TMA were superior compared to those made of SS. Although both from economic and functionality viewpoints the use of TMA is suggested, further clinical investigations are recommended. Key words:Bending moment, optical microscope, spring-back, stainless steel, stiffness, titanium‒molybdenum alloy. PMID:28149469

  3. Infrared repair brazing of 403 stainless steel with a nickel-based braze alloy

    NASA Astrophysics Data System (ADS)

    Shiue, R. K.; Wu, S. K.; Hung, C. M.

    2002-06-01

    Martensitic stainless steel (403SS) is extensively used for intermediate and low-pressure steam turbine blades in fossil-fuel power plants. The purpose of this investigation is to study the repair of shallow cracks on the surface of 403SS steam turbine blades by infrared repair brazing using rapid thermal cycles. A nickel-based braze alloy (NICROBRAZ LM) is used as filler metal. The braze alloy after brazing is primarily comprised of borides and an FeNi3 matrix with different amounts of alloying elements, especially B and Si. As the brazing temperature increases, more Fe atoms are dissolved into the molten braze. Some boron atoms diffuse into the 403SS substrate primarily via grain boundary diffusion and form B-Cr-Fe intermetallic precipitates along the grain boundaries. The LM filler metal demonstrates better performance than 403SS in both microhardness and wear tests. It is also noted that specimens brazed in a vacuum have less porosity than those brazed in an Ar atmosphere. The shear strength of the joint is around 300 MPa except for specimens brazed in short time periods, e.g., 5 seconds in Ar flow and 30 seconds in vacuum. The fractographs mainly consist of brittle fractures and no ductile dimple fractures observed in the scanning electron microscope (SEM) examination.

  4. Release of nickel ions from stainless steel alloys used in dental braces and their patch test reactivity in nickel-sensitive individuals.

    PubMed

    Jensen, Christian Stab; Lisby, Steen; Baadsgaard, Ole; Byrialsen, Kirsten; Menné, Torkil

    2003-06-01

    Nickel ions leached in sufficient quantities from nickel-containing alloys may induce nickel sensitization or elicit allergic contact dermatitis. Nickel-containing stainless steel alloys are generally considered safe for nickel-sensitive individuals to use. The study summarized in this paper investigated 3 parameters. First, the release of nickel was estimated in artificial saliva and sweat from 4 different stainless steel alloys frequently used in dental braces. Second, in a pilot study, oral mucosa cells harvested from 3 dental patients before and after the attachment of dental braces were analysed for possible nickel content. Third, patch test reactivity of the 4 stainless steel alloys was tested on 31 nickel-sensitive subjects. All 4 stainless steel alloys released small amounts of nickel ions into artificial saliva (<0.13 micro g/cm2/week) and artificial sweat (<0.05 micro g/cm2/week), but no measurable amounts of nickel were found in any of the oral mucosa samples. None of the 31 nickel-sensitive subjects reacted to patch testing with the 4 stainless steel alloys, indicating that these stainless steel alloys would be safe to use in direct and prolonged contact with the skin.

  5. Chromium-Makes stainless steel stainless

    USGS Publications Warehouse

    Kropschot, S.J.; Doebrich, Jeff

    2010-01-01

    Chromium, a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point, is a silvery white, hard, and bright metal plating on steel and other material. Commonly known as chrome, it is one of the most important and indispensable industrial metals because of its hardness and resistance to corrosion. But it is used for more than the production of stainless steel and nonferrous alloys; it is also used to create pigments and chemicals used to process leather.

  6. Diffusion brazing nickel-plated stainless steel

    NASA Technical Reports Server (NTRS)

    Beuyukian, C. S.; Mitchell, M. J.

    1976-01-01

    To bond parts, sandwich assembly is made up of aluminum core, aluminum face sheet with brazing alloy interface, and nickel plated stainless steel part. Sandwich is placed between bottom and top glide sheet that is placed in stainless steel retort where assembly is bonded at 580 C.

  7. Welding irradiated stainless steel

    SciTech Connect

    Kanne, W.R. Jr.; Chandler, G.T.; Nelson, D.Z.; Franco-Ferreira, E.A.

    1993-12-31

    Conventional welding processes produced severe underbead cracking in irradiated stainless steel containing 1 to 33 appm helium from n,a reactions. A shallow penetration overlay technique was successfully demonstrated for welding irradiated stainless steel. The technique was applied to irradiated 304 stainless steel that contained 10 appm helium. Surface cracking, present in conventional welds made on the same steel at the same and lower helium concentrations, was eliminated. Underbead cracking was minimal compared to conventional welding methods. However, cracking in the irradiated material was greater than in tritium charged and aged material at the same helium concentrations. The overlay technique provides a potential method for repair or modification of irradiated reactor materials.

  8. Nickel: makes stainless steel strong

    USGS Publications Warehouse

    Boland, Maeve A.

    2012-01-01

    Nickel is a silvery-white metal that is used mainly to make stainless steel and other alloys stronger and better able to withstand extreme temperatures and corrosive environments. Nickel was first identified as a unique element in 1751 by Baron Axel Fredrik Cronstedt, a Swedish mineralogist and chemist. He originally called the element kupfernickel because it was found in rock that looked like copper (kupfer) ore and because miners thought that "bad spirits" (nickel) in the rock were making it difficult for them to extract copper from it. Approximately 80 percent of the primary (not recycled) nickel consumed in the United States in 2011 was used in alloys, such as stainless steel and superalloys. Because nickel increases an alloy's resistance to corrosion and its ability to withstand extreme temperatures, equipment and parts made of nickel-bearing alloys are often used in harsh environments, such as those in chemical plants, petroleum refineries, jet engines, power generation facilities, and offshore installations. Medical equipment, cookware, and cutlery are often made of stainless steel because it is easy to clean and sterilize. All U.S. circulating coins except the penny are made of alloys that contain nickel. Nickel alloys are increasingly being used in making rechargeable batteries for portable computers, power tools, and hybrid and electric vehicles. Nickel is also plated onto such items as bathroom fixtures to reduce corrosion and provide an attractive finish.

  9. Residual stresses in a stainless steel - titanium alloy joint made with the explosive technique

    NASA Astrophysics Data System (ADS)

    Taran, Yu V.; Balagurov, A. M.; Sabirov, B. M.; Evans, A.; Davydov, V.; Venter, A. M.

    2012-02-01

    Joining of pipes from stainless steel (SS) and titanium (Ti) alloy still experience serious technical problems. Recently, reliable and hermetic joining of SS and Ti pipes has been achieved with the explosive bonding technique in the Russian Federal Nuclear Center. Such adapters are earmarked for use at the future International Linear Collider. The manufactured SS-Ti adapters have excellent mechanical behavior at room and liquid nitrogen temperatures, during high-pressure tests and thermal cycling. We here report the first neutron diffraction investigation of the residual stresses in a SS-Ti adapter on the POLDI instrument at the SINQ spallation source. The strain scanning across the adapter walls into the SS-SS and SS-Ti pipes sections encompassed measurement of the axial, radial and hoop strain components, which were transformed into residual stresses. The full stress information was successfully determined for the three steel pipes involved in the joint. The residual stresses do not exceed 300 MPa in magnitude. All stress components have tensile values close to the adapter internal surface, whilst they are compressive close to the outer surface. The strong incoherent and weak coherent neutron scattering cross-sections of Ti did not allow for the reliable determination of stresses inside the titanic pipe.

  10. Compatibility of U-Pu-Zr alloy fuel with stainless steel cladding

    SciTech Connect

    Leibowitz, L.; Hins, A. G.; Strain, R. V.; Tsai, H.; Hofman, G. L.

    1989-07-01

    An important issue in the development of the Integral Fast Reactor is the chemical interaction between fuel and cladding. With a U--Pu--Zr ternary alloy fuel clad in stainless steel, the existence of low-melting eutectics in the U--Fe and Pu--Fe systems must be taken into account. There is at least the possibility that cladding integrity could be compromised by formation of liquid phases during irradiation. Data from a variety of sources have been brought to bear on this issue, and our current state of understanding is summarized in this report. The phase behavior of the relevant systems has been studied to provide a framework for understanding fuel/cladding interactions. Several experimental methods have been used. Differential thermal analysis experiments were performed, and the results compared with those of the phase studies. In addition, experiments were performed in which unirradiated fuel was heated in contact with cladding alloys. The results of these tests were strongly dependent on the state of the contacting surfaces. Other tests were performed in which sections of irradiated fuel with cladding were subjected to carefully controlled heating cycles. In general, there were no inconsistencies in these experimental and analytical studies although the data are still fragmentary. Differences that were observed may be reflections of kinetic factors. 9 refs., 12 figs., 6 tabs.

  11. A mechanical property and stress corrosion evaluation of Custom 455 stainless steel alloy

    NASA Technical Reports Server (NTRS)

    Montano, J. W.

    1972-01-01

    The mechanical and stress corrosion properties are presented of vacuum melted Custom 455 stainless steel alloy bar (1.0-inch diameter) and sheet (0.083-inch thick) material aged at 950 F, 1000 F, and 1050 F. Low temperature mechanical properties were determined at temperatures of 80 F, 0 F, -100 F, and -200 F. For all three aging treatments, the ultimate tensile and 0.2 percent offset yield strengths increased with decreasing test temperatures while the elongation held fairly constant down to -100 F and decreased at -200 F. Reduction in Area decreased moderately with decreasing temperature for the longitudinal round (0.250-inch diameter) specimens. Notched tensile strength and charpy V-notched impact strength decreased with decreasing test temperature. For all three aging treatments, no failures were observed in the unstressed specimens or the specimens stressed to 50, 75, and 100 percent of their yield strengths for 180 days of alternate immersion testing in a 3.5 percent NaCl solution. As indicated by the results of tensile tests performed after alternate immersion testing, the mechanical properties of Custom 455 alloy were not affected by stress or exposure under the conditions of the evaluation.

  12. Electrodeposition of Mn-Co Alloys on Stainless Steels for SOFC Interconnect Application

    SciTech Connect

    Wu, J.; Jiang, Y.; Johnson, C.; Gong, M.; Liu, X.

    2007-09-01

    Chromium-containing ferritic stainless steels are the most popular materials for solid oxide fuel cell (SOFC) interconnect applications because of its oxidation resistance and easy fabrication process. However, excessive scale growth and chromium evaporation will degrade the cell performance. Highly conductive coatings that resist oxide scale growth and chromium evaporation may prevent both of these problems. Mn1.5Co1.5O4 spinel is one of the most promising coatings for interconnect application because of its high conducitivy, good chromium retention capability, as well as good CTE match. Electroplating of alloys or thin film multilayers followed by controlled oxidation to the desired spinel phase offers an additional deposition option. In the present study binary Mn/Co alloys was fabricated by electrodeposition, and polarization curves were used to characterize the cathodic reactions on substrate surface. By controlling the current density precisely, coatings with Mn/Co around 1:1 has been successfully deposited in Mn/Co =10 solutions, SEM and EDX was used to characterize the surface morphology and composition.

  13. Macrophage responses to 316L stainless steel and cobalt chromium alloys with different surface topographies.

    PubMed

    Anderson, Jordan A; Lamichhane, Sujan; Mani, Gopinath

    2016-11-01

    The surface topography of a biomaterial plays a vital role in determining macrophage interactions and influencing immune response. In this study, we investigated the effect of smooth and microrough topographies of commonly used metallic biomaterials such as 316 L stainless steel (SS) and cobalt-chromium (CoCr) alloys on macrophage interactions. The macrophage adhesion was greater on CoCr compared to SS, irrespective of their topographies. The macrophage activation and the secretion of most pro-inflammatory cytokines (TNF-α, IL-6, and IP-10) were greater on microrough surfaces than on smooth surfaces by day-1. However, by day-2, the macrophage activation on smooth surfaces was also significantly increased up to the same level as observed on the microrough surfaces, with more amount of cytokines secreted. The secretion of anti-inflammatory cytokine (IL-10) was significantly increased from day-1 to day-2 on all the alloy surfaces with the effect most prominently observed on microrough surfaces. The production of nitric oxide by the macrophages did not show any major substrate-dependent effect. The foreign body giant cells formed by macrophages were least observed on the microrough surfaces of CoCr. Thus, this study demonstrated that the nature of material (SS or CoCr) and their surface topographies (smooth or microrough) strongly influence the macrophage responses. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2658-2672, 2016.

  14. Evaluation of pitting corrosion resistance of high-alloyed stainless steels welds for FGD plants in Korea

    SciTech Connect

    Baek, K.K.; Sung, H.J.; Im, C.S.; Hong, I.P.; Kim, D.K.

    1998-12-31

    For successful application of high-alloyed stainless steels for Flue Gas Desulfurization (FGD) plants, pitting corrosion resistance of arc welds of N-added 6%Mo austenitic stainless steels (UNS N 08367) and super duplex stainless steels (UNS S 32550) made with various filler metals were evaluated using the Green Death solution. For Gas Tungsten Arc (GTA) and Gas Metal Arc (GMA) welds of N 08367, Critical Pitting Temperature (CPT) of base metal was 65--70 C, whereas weld made by ERNiCrMo-3 filler metal yielded CPT of 50 C. Welds made by ERNiCrMo-10 or ERNiCrMo-4 filler metals showed CPT of 60--65 C and 65--70C, respectively. For GTA and GMA welds of S 32550, CPT of welds made by ERNiCrMo-3 was 45--50 C, indicating that the filler metal can provide pitting corrosion resistance matching the S 32550 alloy. Thus, a proper pitting corrosion resistance of weldments of high-alloy stainless steels can be achieved by selecting filler metals having at least +10 higher Pitting Resistance Equivalent Number (PRE{sub N}) value than the base metal regardless of the type of arc welding process. The over-alloyed filler metals would compensate preferential segregation of Cr, MO along the dendrite boundary, which made the dendrite core more susceptible to pitting. Nitrogen addition to the GTA welds of N 08367 made with ERNiCrMo-3 failed to improve pitting corrosion resistance, which was attributed to the precipitation of nitrogen in the weld metal in the form of Nb-nitride.

  15. A comparative evaluation of welding consumables for dissimilar weids between 316LN austenitic stainless steel and Alloy 800

    NASA Astrophysics Data System (ADS)

    Sireesha, M.; Albert, Shaju K.; Shankar, V.; Sundaresan, S.

    2000-03-01

    Transition joints in power plants between ferritic steels and austenitic stainless steels suffer from a mismatch in coefficients of thermal expansion (CTE) and the migration of carbon during service from the ferritic to the austenitic steel. To overcome these, nickel-based consumables are commonly used. The use of a trimetallic combination with an insert piece of intermediate CTE provides for a more effective lowering of thermal stresses. The current work envisages a trimetallic joint involving modified 9Cr-1Mo steel and 316LN austenitic stainless steel as the base materials and Alloy 800 as the intermediate piece. Of the two joints involved, this paper describes the choice of welding consumables for the joint between Alloy 800 and 316LN. Four consumables were examined: 316, 16-8-2, Inconel 82 and Inconel 182. The comparative evaluation was based on hot cracking tests and estimation of mechanical properties and coefficient of thermal expansion. While 16-8-2 exhibited highest resistance to solidification cracking, the Inconel filler materials also showed adequate resistance; additionally, the latter were superior from the mechanical property and coefficient of thermal expansion view-points. It is therefore concluded that for the joint between Alloy 800 and 316LN the Inconel filler materials offer the best compromise.

  16. Effect of welding process on the microstructure and properties of dissimilar weld joints between low alloy steel and duplex stainless steel

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Lu, Min-xu; Zhang, Lei; Chang, Wei; Xu, Li-ning; Hu, Li-hua

    2012-06-01

    To obtain high-quality dissimilar weld joints, the processes of metal inert gas (MIG) welding and tungsten inert gas (TIG) welding for duplex stainless steel (DSS) and low alloy steel were compared in this paper. The microstructure and corrosion morphology of dissimilar weld joints were observed by scanning electron microscopy (SEM); the chemical compositions in different zones were detected by energy-dispersive spectroscopy (EDS); the mechanical properties were measured by microhardness test, tensile test, and impact test; the corrosion behavior was evaluated by polarization curves. Obvious concentration gradients of Ni and Cr exist between the fusion boundary and the type II boundary, where the hardness is much higher. The impact toughness of weld metal by MIG welding is higher than that by TIG welding. The corrosion current density of TIG weld metal is higher than that of MIG weld metal in a 3.5wt% NaCl solution. Galvanic corrosion happens between low alloy steel and weld metal, revealing the weakness of low alloy steel in industrial service. The quality of joints produced by MIG welding is better than that by TIG welding in mechanical performance and corrosion resistance. MIG welding with the filler metal ER2009 is the suitable welding process for dissimilar metals jointing between UNS S31803 duplex stainless steel and low alloy steel in practical application.

  17. Stainless Steel Permeability

    SciTech Connect

    Buchenauer, Dean A.; Karnesky, Richard A.

    2015-09-01

    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 the 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.

  18. Structure and Properties of High-Temperature Multilayer Hybrid Material Based on Vanadium Alloy and Stainless Steel

    NASA Astrophysics Data System (ADS)

    Nechaykina, Tatyana A.; Nikulin, Sergey A.; Rozhnov, Andrey B.; Khatkevich, Vladimir M.; Rogachev, Stanislav O.

    2017-01-01

    The present work is devoted to the development of new structural composite material having the unique complex of properties for operating in ultrahard conditions that combine high temperatures, radiation, and aggressive environments. A new three-layer composite tube material based on vanadium alloy (V-4Ti-4Cr) protected by stainless steel (Fe-0.2C-13Cr) has been obtained by co-extrusion. Mechanism and kinetics of formation as well as structure, composition, and mechanical properties of "transition" area between vanadium alloy and stainless steel have been studied. The transition area (13- to 22-µm thick) of the diffusion interaction between vanadium alloy and steel was formed after co-extrusion. The microstructure in the transition area was rather complicated comprising different grain sizes in components, but having no defects or brittle phases. Tensile strength of the composite was an average 493 ± 22 MPa, and the elongation was 26 ± 3 pct. Annealing at 1073 K (800 °C) increased the thickness of transition area up to 1.2 times, homogenized microstructure, and slightly changed mechanical properties. Annealing at 1273 K (1000 °C) further increased the thickness of transition area and also lead to intensive grain growth in steel and sometimes to separation between composite components during tensile tests. Annealing at 1073 K (800 °C) is proposed as appropriate heat treatment after co-extrusion of composite providing balance between diffusion interaction thickness and microstructure and monolithic-like behavior of composite during tensile tests.

  19. Structure and Properties of High-Temperature Multilayer Hybrid Material Based on Vanadium Alloy and Stainless Steel

    NASA Astrophysics Data System (ADS)

    Nechaykina, Tatyana A.; Nikulin, Sergey A.; Rozhnov, Andrey B.; Khatkevich, Vladimir M.; Rogachev, Stanislav O.

    2017-03-01

    The present work is devoted to the development of new structural composite material having the unique complex of properties for operating in ultrahard conditions that combine high temperatures, radiation, and aggressive environments. A new three-layer composite tube material based on vanadium alloy (V-4Ti-4Cr) protected by stainless steel (Fe-0.2C-13Cr) has been obtained by co-extrusion. Mechanism and kinetics of formation as well as structure, composition, and mechanical properties of "transition" area between vanadium alloy and stainless steel have been studied. The transition area (13- to 22- µm thick) of the diffusion interaction between vanadium alloy and steel was formed after co-extrusion. The microstructure in the transition area was rather complicated comprising different grain sizes in components, but having no defects or brittle phases. Tensile strength of the composite was an average 493 ± 22 MPa, and the elongation was 26 ± 3 pct. Annealing at 1073 K (800 °C) increased the thickness of transition area up to 1.2 times, homogenized microstructure, and slightly changed mechanical properties. Annealing at 1273 K (1000 °C) further increased the thickness of transition area and also lead to intensive grain growth in steel and sometimes to separation between composite components during tensile tests. Annealing at 1073 K (800 °C) is proposed as appropriate heat treatment after co-extrusion of composite providing balance between diffusion interaction thickness and microstructure and monolithic-like behavior of composite during tensile tests.

  20. Erosive Wear Behavior of High-Alloy Cast Iron and Duplex Stainless Steel under Mining Conditions

    NASA Astrophysics Data System (ADS)

    Yoganandh, J.; Natarajan, S.; Kumaresh Babu, S. P.

    2015-09-01

    Centrifugal pumps used in the lignite mines encounter erosive wear problems, leading to a disastrous failure of the pump casings. This paper attempts to evaluate the erosive wear resistance of Ni-Hard 4, high-chromium iron, and Cast CD4MCu duplex stainless steel (DSS), for mining conditions. The prepared test coupons were subjected to an erosion test by varying the impingement velocity and the angle of impingement, under two different pH conditions of 3 and 7, which pertained to the mining conditions. XRD analysis was carried out to confirm the phases present in the alloy. The eroded surface was subjected to SEM analysis to identify the erosion mechanisms. The surface degradation of Ni-Hard 4 and high-chromium iron came from a low-angle abrasion with a grooving and plowing mechanism at a low angle of impingement. At normal impingement, deep indentations resulted in lips and crater formations, leading to degradation of the surface in a brittle manner. A combined extrusion-forging mechanism is observed in the CD4MCu DSS surface at all the impingement angles.

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

    PubMed

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

    2013-01-01

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

  2. Laser-Arc Hybrid Welding of Dissimilar Titanium Alloy and Stainless Steel Using Copper Wire

    NASA Astrophysics Data System (ADS)

    Gao, Ming; Chen, Cong; Wang, Lei; Wang, Zemin; Zeng, Xiaoyan

    2015-05-01

    Laser-arc hybrid welding with Cu3Si filler wire was employed to join dissimilar Ti6Al4V titanium alloy and AISI316 stainless steel (316SS). The effects of welding parameters on bead shape, microstructure, mechanical properties, and fracture behavior were investigated in detail. The results show that cross-weld tensile strength of the joints is up to 212 MPa. In the joint, obvious nonuniformity of the microstructure is found in the fusion zone (FZ) and at the interfaces from the top to the bottom, which could be improved by increasing heat input. For the homogeneous joint, the FZ is characterized by Fe67- x Si x Ti33 dendrites spreading on α-Cu matrix, and the two interfaces of 316SS/FZ and FZ/Ti6Al4V are characterized by a bamboo-like 316SS layer and a CuTi2 layer, respectively. All the tensile samples fractured in the hardest CuTi2 layer at Ti6Al4V side of the joints. The fracture surface is characterized by river pattern revealing brittle cleavage fracture. The bead formation mechanisms were discussed according to the melt flow and the thermodynamic calculation.

  3. Evaluation of Alumina-Forming Austenitic Stainless Steel Alloys in Microturbines

    SciTech Connect

    Brady, M.P.; Matthews, W.J.

    2010-09-15

    Oak Ridge National Laboratory (ORNL) and Capstone Turbine Corporation (CTC) participated in an in-kind cost share cooperative research and development agreement (CRADA) effort under the auspices of the Energy Efficiency and Renewable Energy (EERE) Technology Maturation Program to explore the feasibility for use of developmental ORNL alumina-forming austenitic (AFA) stainless steels as a material of construction for microturbine recuperator components. ORNL delivered test coupons of three different AFA compositions to CTC. The coupons were exposed in steady-state elevated turbine exit temperature (TET) engine testing, with coupons removed for analysis after accumulating ~1,500, 3,000, 4,500, and 6,000 hours of operation. Companion test coupons were also exposed in oxidation testing at ORNL at 700-800°C in air with 10% H2O. Post test assessment of the coupons was performed at ORNL by light microscopy and electron probe microanalysis. The higher Al and Nb containing AFA alloys exhibited excellent resistance to oxidation/corrosion, and thus show good promise for recuperator applications.

  4. 21 CFR 872.3350 - Gold or stainless steel cusp.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gold or stainless steel cusp. 872.3350 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3350 Gold or stainless steel cusp. (a) Identification. A gold or stainless steel cusp is a prefabricated device made of austenitic alloys or...

  5. 21 CFR 872.3350 - Gold or stainless steel cusp.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gold or stainless steel cusp. 872.3350 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3350 Gold or stainless steel cusp. (a) Identification. A gold or stainless steel cusp is a prefabricated device made of austenitic alloys or...

  6. 21 CFR 872.3350 - Gold or stainless steel cusp.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gold or stainless steel cusp. 872.3350 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3350 Gold or stainless steel cusp. (a) Identification. A gold or stainless steel cusp is a prefabricated device made of austenitic alloys or...

  7. 21 CFR 872.3350 - Gold or stainless steel cusp.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gold or stainless steel cusp. 872.3350 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3350 Gold or stainless steel cusp. (a) Identification. A gold or stainless steel cusp is a prefabricated device made of austenitic alloys or...

  8. 21 CFR 872.3350 - Gold or stainless steel cusp.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gold or stainless steel cusp. 872.3350 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3350 Gold or stainless steel cusp. (a) Identification. A gold or stainless steel cusp is a prefabricated device made of austenitic alloys or...

  9. Austenitic stainless steel alloys having improved resistance to fast neutron-induced swelling

    DOEpatents

    Bloom, Everett E.; Stiegler, James O.; Rowcliffe, Arthur F.; Leitnaker, James M.

    1979-01-01

    The present invention is based on the discovery that radiation-induced voids which occur during fast neutron irradiation can be controlled by small but effective additions of titanium and silicon. The void-suppressing effect of these metals in combination is demonstrated and particularly apparent in austenitic stainless steels.

  10. Austenitic stainless steel alloys having improved resistance to fast neutron-induced swelling

    DOEpatents

    Bloom, Everett E.; Stiegler, James O.; Rowcliffe, Arthur F.; Leitnaker, James M.

    1977-03-08

    The present invention is based on the discovery that radiation-induced voids which occur during fast neutron irradiation can be controlled by small but effective additions of titanium and silicon. The void-suppressing effect of these metals in combination is demonstrated and particularly apparent in austenitic stainless steels.

  11. Study of magnetism in Ni-Cr hardface alloy deposit on 316LN stainless steel using magnetic force microscopy

    NASA Astrophysics Data System (ADS)

    Kishore, G. V. K.; Kumar, Anish; Chakraborty, Gopa; Albert, S. K.; Rao, B. Purna Chandra; Bhaduri, A. K.; Jayakumar, T.

    2015-07-01

    Nickel base Ni-Cr alloy variants are extensively used for hardfacing of austenitic stainless steel components in sodium cooled fast reactors (SFRs) to avoid self-welding and galling. Considerable difference in the compositions and melting points of the substrate and the Ni-Cr alloy results in significant dilution of the hardface deposit from the substrate. Even though, both the deposit and the substrate are non-magnetic, the diluted region exhibits ferromagnetic behavior. The present paper reports a systematic study carried out on the variations in microstructures and magnetic behavior of American Welding Society (AWS) Ni Cr-C deposited layers on 316 LN austenitic stainless steels, using atomic force microscopy (AFM) and magnetic force microscopy (MFM). The phase variations of the oscillations of a Co-Cr alloy coated magnetic field sensitive cantilever is used to quantitatively study the magnetic strength of the evolved microstructure in the diluted region as a function of the distance from the deposit/substrate interface, with the spatial resolution of about 100 nm. The acquired AFM/MFM images and the magnetic property profiles have been correlated with the variations in the chemical compositions in the diluted layers obtained by the energy dispersive spectroscopy (EDS). The study indicates that both the volume fraction of the ferromagnetic phase and its ferromagnetic strength decrease with increasing distance from the deposit/substrate interface. A distinct difference is observed in the ferromagnetic strength in the first few layers and the ferromagnetism is observed only near to the precipitates in the fifth layer. The study provides a better insight of the evolution of ferromagnetism in the diluted layers of Ni-Cr alloy deposits on stainless steel.

  12. Development of New Stainless Steel

    SciTech Connect

    Robert F. Buck

    2005-08-30

    A new family of innovative martensitic stainless steels, 521-A, 521-B, and 521-C has been developed by Advanced Steel Technology, LLC (Trafford, PA) as high strength fastener (bolt) materials for use at moderate temperatures in turbine engines, including steam turbines, gas turbines, and aircraft engines. The primary objective of the development program was to create a martensitic stainless steel with high strength at moderate temperatures, and which could replace the expensive nickel-based superalloy IN 718 in some fasteners applications. A secondary objective was to replace conventional 12Cr steels such as AISI 422 used as blades, buckets and shafts that operate at intermediate temperatures in turbine engines with stronger steel. The composition of the new alloys was specifically designed to produce excellent mechanical properties while integrating heat treatment steps into production to reduce energy consumption during manufacturing. As a result, production costs and energy consumption during production of rolled bar products is significantly lower than conventional materials. Successful commercialization of the new alloys would permit the installed cost of certain turbine engines to be reduced without sacrificing high availability or operational flexibility, thereby enhancing the global competitiveness of U.S. turbine engine manufacturers. Moreover, the domestic specialty steel industry would also benefit through increased productivity and reduced operating costs, while increasing their share of the international market for turbine engine fasteners, blades, buckets and shafts.

  13. Gas atomized precursor alloy powder for oxide dispersion strengthened ferritic stainless steel

    SciTech Connect

    Rieken, Joel

    2011-12-13

    Gas atomization reaction synthesis (GARS) was employed as a simplified method for producing precursor powders for oxide dispersion strengthened (ODS) ferritic stainless steels (e.g., Fe-Cr-Y-(Ti,Hf)-O), departing from the conventional mechanical alloying (MA) process. During GARS processing a reactive atomization gas (i.e., Ar-O2) was used to oxidize the powder surfaces during primary break-up and rapid solidification of the molten alloy. This resulted in envelopment of the powders by an ultra-thin (t < 150 nm) metastable Cr-enriched oxide layer that was used as a vehicle for solid-state transport of O into the consolidated microstructure. In an attempt to better understand the kinetics of this GARS reaction, theoretical cooling curves for the atomized droplets were calculated and used to establish an oxidation model for this process. Subsequent elevated temperature heat treatments, which were derived from Rhines pack measurements using an internal oxidation model, were used to promote thermodynamically driven O exchange reactions between trapped films of the initial Cr-enriched surface oxide and internal Y-enriched intermetallic precipitates. This novel microstructural evolution process resulted in the successful formation of nano-metric Y-enriched dispersoids, as confirmed using high energy X-ray diffraction and transmission electron microscopy (TEM), equivalent to conventional ODS alloys from MA powders. The thermal stability of these Y-enriched dispersoids was evaluated using high temperature (1200°C) annealing treatments ranging from 2.5 to 1,000 hrs of exposure. In a further departure from current ODS practice, replacing Ti with additions of Hf appeared to improve the Y-enriched dispersoid thermal stability by means of crystal structure modification. Additionally, the spatial distribution of the dispersoids was found to depend strongly on the original rapidly solidified microstructure. To exploit this, ODS microstructures were engineered from

  14. Gas atomized precursor alloy powder for oxide dispersion strengthened ferritic stainless steel

    NASA Astrophysics Data System (ADS)

    Rieken, Joel Rodney

    Gas atomization reaction synthesis (GARS) was employed as a simplified method for producing precursor powders for oxide dispersion strengthened (ODS) ferritic stainless steels (e.g., Fe-Cr-Y-(Ti,Hf)-O), departing from the conventional mechanical alloying (MA) process. During GARS processing a reactive atomization gas (i.e., Ar-O2) was used to oxidize the powder surfaces during primary break-up and rapid solidification of the molten alloy. This resulted in envelopment of the powders by an ultra-thin (t < 150 nm) metastable Cr-enriched oxide layer that was used as a vehicle for solid-state transport of O into the consolidated microstructure. In an attempt to better understand the kinetics of this GARS reaction, theoretical cooling curves for the atomized droplets were calculated and used to establish an oxidation model for this process. Subsequent elevated temperature heat treatments, which were derived from Rhines pack measurements using an internal oxidation model, were used to promote thermodynamically driven O exchange reactions between trapped films of the initial Cr-enriched surface oxide and internal Y-enriched intermetallic precipitates. This novel microstructural evolution process resulted in the successful formation of nano-metric Y-enriched dispersoids, as confirmed using high energy X-ray diffraction and transmission electron microscopy (TEM), equivalent to conventional ODS alloys from MA powders. The thermal stability of these Y-enriched dispersoids was evaluated using high temperature (1200°C) annealing treatments ranging from 2.5 to 1,000 hrs of exposure. In a further departure from current ODS practice, replacing Ti with additions of Hf appeared to improve the Y-enriched dispersoid thermal stability by means of crystal structure modification. Additionally, the spatial distribution of the dispersoids was found to depend strongly on the original rapidly solidified microstructure. To exploit this, ODS microstructures were engineered from different

  15. Stainless steel tanks

    SciTech Connect

    Hagen, T.

    1995-12-31

    There is currently no recognized code or standard for the design, fabrication and construction of atmospheric and low pressure stainless steel tanks. At the present time these tanks are being designed to individual specifications, manufacturers standards or utilizing other codes and standards that may not be entirely applicable. Recognizing the need, the American Petroleum Institute will be publishing a new appendix to the API STD 650 Standard which will cover stainless steel tanks. The new Appendix was put together by a Task Group of selected individuals from the API Subcommittee of Pressure Vessels and Tanks from the Committee on Refinery Equipment. This paper deals with the development and basis of the new appendix. The new appendix will provide a much needed standard to cover the material, design, fabrication, erection and testing requirements for vertical, cylindrical, austenitic stainless steel aboveground tanks in nonrefrigerated service.

  16. Elucidating the Effect of Alloying Elements on the Behavior of Austenitic Stainless Steels at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Naghizadeh, Meysam; Mirzadeh, Hamed

    2016-12-01

    The effect of carbon and molybdenum on elevated temperature behavior of austenitic stainless steels was studied. It was revealed that carbon does not alter the overall grain coarsening behavior but molybdenum significantly retards the growth of grains toward higher temperatures and slower kinetics and effectively increases the grain growth activation energy due to an interaction energy between Mo and grain boundaries. These observations were based on especial activation energy plots, which facilitate the interpretation of results.

  17. Cavitation Erosion of Electro Spark Deposited Nitinol vs. Stellite Alloy on Stainless Steel Substrate

    DTIC Science & Technology

    2015-07-15

    the substrate (Figure 2-2). Rapid solidification produces nano -structures with unique tribological and metallurgical characteristics. When...inventor of electro spark deposition methodology and apparatus. [18] ASAP now terms their process “ nano -fusion” and states that it is generations...stainless might be the root cause of the poor compatibility. ASAP also nano -fused Nitinol onto mild steel coupons, which produced somewhat better results

  18. Influence of alloy content and a cerium surface treatment on the oxidation behavior of Fe-Cr ferritic stainless steels

    SciTech Connect

    Alman, D.E.; Jablonski, P.D.

    2006-01-01

    The cost of solid oxide fuel cells (SOFC) can be significantly reduced by using interconnects made from ferritic stainless steels. In fact, several alloys have been developed specifically for this application (Crofer 22APU and Hitachi ZMG323). However, these steels lack environmental stability in SOFC environments, and as a result, degrade the performance of the SOFC. A steel interconnect can contribute to performance degradation through: (i) Cr poisoning of electrochemically active sites within the cathode; (ii) formation of non-conductive oxides, such as SiO2 or Al2O3 from residual or minor alloying elements, at the base metal-oxide scale interface; and/or (iii) excessive oxide scale growth, which may also retard electrical conductivity. Consequently, there has been considerable attention on developing coatings to protect steel interconnects in SOFC environments and controlling trace elements during alloy production. Recently, we have reported on the development of a Cerium surface treatment that improves the oxidation behavior of a variety alloys, including Crofer 22APU [1-5]. Initial results indicated that the treatment may improve the performance of Crofer 22APU for SOFC application by: (i) retarding scale growth resulting in a thinner oxide scale; and (ii) suppressing the formation of a deleterious continuous SiO2 layer that can form at the metal-oxide scale interface in materials with high residual Si content [5]. Crofer 22 APU contains Fe-22Cr-0.5Mn-0.1Ti (weight percent). Depending on current market prices and the purity of raw materials utilized for ingot production, Cr can contribute upwards of 90 percent of the raw materials cost. The present research was undertaken to determine the influence of Cr content and minor element additions, especially Ti, on the effectiveness of the Ce surface treatment. Particular emphasis is placed on the behavior of low Cr alloys.

  19. Cracking behavior and microstructure of austenitic stainless steels and alloy 690 irradiated in BOR-60 reactor, phase I.

    SciTech Connect

    Chen, Y.; Chopra, O. K.; Soppet, W. K.; Shack, W. J.; Yang, Y.; Allen, T. R.; Univ. of Wisconsin at Madison

    2010-02-16

    Cracking behavior of stainless steels specimens irradiated in the BOR-60 at about 320 C is studied. The primary objective of this research is to improve the mechanistic understanding of irradiation-assisted stress corrosion cracking (IASCC) of core internal components under conditions relevant to pressurized water reactors. The current report covers several baseline tests in air, a comparison study in high-dissolved-oxygen environment, and TEM characterization of irradiation defect structure. Slow strain rate tensile (SSRT) tests were conducted in air and in high-dissolved-oxygen (DO) water with selected 5- and 10-dpa specimens. The results in high-DO water were compared with those from earlier tests with identical materials irradiated in the Halden reactor to a similar dose. The SSRT tests produced similar results among different materials irradiated in the Halden and BOR-60 reactors. However, the post-irradiation strength for the BOR-60 specimens was consistently lower than that of the corresponding Halden specimens. The elongation of the BOR-60 specimens was also greater than that of their Halden specimens. Intergranular cracking in high-DO water was consistent for most of the tested materials in the Halden and BOR-60 irradiations. Nonetheless, the BOR-60 irradiation was somewhat less effective in stimulating IG fracture among the tested materials. Microstructural characterization was also carried out using transmission electron microscopy on selected BOR-60 specimens irradiated to {approx}25 dpa. No voids were observed in irradiated austenitic stainless steels and cast stainless steels, while a few voids were found in base and grain-boundary-engineered Alloy 690. All the irradiated microstructures were dominated by a high density of Frank loops, which varied in mean size and density for different alloys.

  20. The influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes in seawater

    NASA Astrophysics Data System (ADS)

    Bai, Qiang; Zou, Yan; Kong, Xiangfeng; Gao, Yang; Dong, Sheng; Zhang, Wei

    2017-02-01

    The high strength low-alloy steels are welded by underwater wet welding with stainless steel electrodes. The micro-structural and electrochemical corrosion study of base metal (BM), weld zone (WZ) and heat affected zone (HAZ) are carried out to understand the influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes, methods used including, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The results indicate that the WZ acts as a cathode and there is no corrosion product on it throughout the immersion period in seawater. The HAZ and BM acts as anodes. The corrosion rates of the HAZ and BM change with the immersion time increasing. In the initial immersion period, the HAZ has the highest corrosion rate because it has a coarse tempered martensite structure and the BM exhibites a microstructure with very fine grains of ferrite and pearlite. After a period of immersion, the BM has the highest corrosion rate. The reason is that the corrosion product layer on the HAZ is dense and has a better protective property while that on the BM is loose and can not inhibit the diffusion of oxygen.

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

    PubMed

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

    2015-02-01

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

  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. Corrosion of austenitic and martensitic stainless steels in flowing 17Li83Pb alloy

    NASA Astrophysics Data System (ADS)

    Broc, M.; Flament, T.; Fauvet, P.; Sannier, J.

    1988-07-01

    With regard to the behaviour of 316 L stainless steel at 400°C in flowing anisothermal 17Li83Pb the mass transfer suffered by this steel appears to be quite important without noticeable influence of constant or cyclic stress. Evaluation made from solution-annealed specimens leads to a corrosion rate of approximately 30 μm yr -1 at steady state to which a depth of 25 μm has to be added to take into account the initial period phenomena. On the other hand, with semi-stagnant 17Li83Pb at 400° C, the mass transfer of 316 L steel appears to be lower and more acceptable after a 3000-h exposure; but long-time kinetics data have to be achieved in order to see if that better behaviour is persistent and does not correspond to a longer incubation period. As for the martensitic steels their corrosion rate at 450°C in the thermal convection loop TULIP is constant up to 3000 h and five times lower than that observed for 316 L steel in the same conditions.

  4. Laser Metal Deposition as Repair Technology for Stainless Steel and Titanium Alloys

    NASA Astrophysics Data System (ADS)

    Graf, Benjamin; Gumenyuk, Andrey; Rethmeier, Michael

    In a repair process chain, damaged areas or cracks can be removed by milling and subsequently be reconditioned with new material deposition. The use of laser metal deposition has been investigated for this purpose. The material has been deposited into different groove shapes, using both stainless steel and Ti-6Al-4 V. The influence of welding parameters on the microstructure and the heat affected zone has been studied. The parameters have been modified in order to achieve low heat input and consequently low distortion as well as low metallurgical impact. Finally, an evaluation of the opportunities for an automatized repair process is made.

  5. Enhancement of thermal stability of porous bodies comprised of stainless steel or an alloy

    DOEpatents

    Bischoff, Brian L.; Sutton, Theodore G.; Judkins, Roddie R.; Armstrong, Timothy R.; Adcock, Kenneth D.

    2010-11-09

    A method for treating a porous item constructed of metal powder, such as a powder made of Series 400 stainless steel, involves a step of preheating the porous item to a temperature of between about 700 and 900.degree. C. degrees in an oxidizing atmosphere and then sintering the body in an inert or reducing atmosphere at a temperature which is slightly below the melting temperature of the metal which comprises the porous item. The thermal stability of the resulting item is enhanced by this method so that the item retains its porosity and metallic characteristics, such as ductility, at higher (e.g. near-melting) temperatures.

  6. Superplastic forming of stainless steel automotive components

    SciTech Connect

    Bridges, B.; Elmer, J.; Carol, L.

    1997-02-06

    Exhaust emission standards are governmentally controlled standards, which are increasingly stringent, forcing alternate strategies to meet these standards. One approach to improve the efficiency of the exhaust emission equipment is to decrease the time required to get the catalytic converter to optimum operating temperature. To accomplish this, automotive manufacturers are using double wall stainless steel exhaust manifolds to reduce heat loss of the exhaust gases to the converter. The current method to manufacture double wall stainless steel exhaust components is to use a low-cost alloy with good forming properties and extensively form, cut, assemble, and weld the pieces. Superplastic forming (SPF) technology along with alloy improvements has potential at making this process more cost effective. Lockheed Martin Energy Systems (LMES), Lawrence Livermore National Laboratory (LLNL) and USCAR Low Emission Partnership (LEP) worked under a Cooperative Research And Development Agreement (CRADA) to evaluate material properties, SPF behavior, and welding behavior of duplex stainless steel alloy for automotive component manufacturing. Battelle Pacific Northwest National Laboratory (PNNL) has a separate CRADA with the LEP to use SPF technology to manufacture a double wall stainless steel exhaust component. As a team these CRADAs developed and demonstrated a technical plan to accomplish making double wall stainless steel exhaust manifolds.

  7. Manufacture of Alumina-Forming Austenitic Stainless Steel Alloys by Conventional Casting and Hot-Working Methods

    SciTech Connect

    Brady, M.P.; Yamamoto, Y.; Magee, J.H.

    2009-03-23

    Oak Ridge National Laboratory (ORNL) and Carpenter Technology Corporation (CarTech) participated in an in-kind cost share cooperative research and development agreement (CRADA) effort under the auspices of the Energy Efficiency and Renewable Energy (EERE) Technology Maturation program to explore the feasibility for scale up of developmental ORNL alumina-forming austenitic (AFA) stainless steels by conventional casting and rolling techniques. CarTech successfully vacuum melted 30lb heats of four AFA alloy compositions in the range of Fe-(20-25)Ni-(12-14)Cr-(3-4)Al-(1-2.5)Nb wt.% base. Conventional hot/cold rolling was used to produce 0.5-inch thick plate and 0.1-inch thick sheet product. ORNL subsequently successfully rolled the 0.1-inch sheet to 4 mil thick foil. Long-term oxidation studies of the plate form material were initiated at 650, 700, and 800 C in air with 10 volume percent water vapor. Preliminary results indicated that the alloys exhibit comparable (good) oxidation resistance to ORNL laboratory scale AFA alloy arc casting previously evaluated. The sheet and foil material will be used in ongoing evaluation efforts for oxidation and creep resistance under related CRADAs with two gas turbine engine manufacturers. This work will be directed to evaluation of AFA alloys for use in gas turbine recuperators to permit higher-temperature operating conditions for improved efficiencies and reduced environmental emissions.

  8. Monte Carlo simulation of spinodal decomposition in a ternary alloy within a three-phases field: comparison to phase transformation of ferrite in duplex stainless steels

    NASA Astrophysics Data System (ADS)

    Emo, Jonathan; Pareige, Cristelle; Saillet, Sébastien; Domain, Christophe; Pareige, Philippe

    2014-06-01

    This work proposes to model phase transformations occurring in duplex stainless steels using atomistic kinetic Monte Carlo in a ternary model alloy. Kinetics are simulated in the three-phase field of a ternary system. Influence of the precipitation of the third phase on the kinetic of spinodal decomposition between the two other phases is studied in order to understand the synergy between spinodal decomposition and G-phase precipitation which exists in duplex stainless steels. Simulation results are compared to experimental data obtained with atom probe tomography.

  9. Evaluation of Stress Corrosion Cracking Susceptibility Using Fracture Mechanics Techniques, Part 1. [environmental tests of aluminum alloys, stainless steels, and titanium alloys

    NASA Technical Reports Server (NTRS)

    Sprowls, D. O.; Shumaker, M. B.; Walsh, J. D.; Coursen, J. W.

    1973-01-01

    Stress corrosion cracking (SSC) tests were performed on 13 aluminum alloys, 13 precipitation hardening stainless steels, and two titanium 6Al-4V alloy forgings to compare fracture mechanics techniques with the conventional smooth specimen procedures. Commercially fabricated plate and rolled or forged bars 2 to 2.5-in. thick were tested. Exposures were conducted outdoors in a seacoast atmosphere and in an inland industrial atmosphere to relate the accelerated tests with service type environments. With the fracture mechanics technique tests were made chiefly on bolt loaded fatigue precracked compact tension specimens of the type used for plane-strain fracture toughness tests. Additional tests of the aluminum alloy were performed on ring loaded compact tension specimens and on bolt loaded double cantilever beams. For the smooth specimen procedure 0.125-in. dia. tensile specimens were loaded axially in constant deformation type frames. For both aluminum and steel alloys comparative SCC growth rates obtained from tests of precracked specimens provide an additional useful characterization of the SCC behavior of an alloy.

  10. A mechanical property and stress corrosion evaluation of 431 stainless steel alloy

    NASA Technical Reports Server (NTRS)

    Montano, J. W.

    1973-01-01

    The mechanical properties of type 431 stainless steel in two conditions: annealed bar and hardened and tempered bar are presented. Test specimens, manufactured from approximately 1.0 inch (2.54 cm) diameter bar stock, were tested at temperatures of 80 F (+26.7 C), 0 F (-17.8 C), -100 F (-73 C), and -200 F (-129 C). The test data indicated excellent tensile strength, notched/unnotched tensile ratio, ductility, shear, and impact properties at all testing temperatures. Results of the alternate immersion stress corrosion tests on stressed and unstressed longitudinal tensile specimens 0.1250 inch (0.3175 cm) diameter and transverse C-ring specimens, machined from 1.0 inch (2.54 cm) diameter bar stock, indicated that the material is not susceptible to stress corrosion cracking when tested in a 3.5 percent NaCl solution for 180 days.

  11. Dynamic strain ageing in prior cold worked 15Cr 15Ni titanium modified stainless steel (Alloy D9)

    NASA Astrophysics Data System (ADS)

    Samuel, K. G.; Ray, S. K.; Sasikala, G.

    2006-09-01

    Dynamic strain ageing (DSA) behavior of a 20% prior cold worked titanium modified austenitic stainless steel (Alloy D9) was investigated in the temperature range 300-1023 K at a constant (nominal) strain rate of 1.33 × 10 -3 s -1. Serrated plastic flow was observed in a narrow temperature region of 773-873 K. Anomalies characteristic of DSA were observed in the variations of strength, ductility, and strain hardening parameters with temperature. Specifically, the difference between ultimate tensile stress and yield stress indicated that a single DSA mechanism is operative over the range of observations. Plastic strain energy density for uniform deformation showed a peak in the DSA temperature range, suggesting that in this material, DSA should enhance the ductile fracture resistance.

  12. Friction Stir Welding of Stainless Steel to Al Alloy: Effect of Thermal Condition on Weld Nugget Microstructure

    NASA Astrophysics Data System (ADS)

    Ghosh, M.; Gupta, R. K.; Husain, M. M.

    2014-02-01

    Joining of dissimilar materials is always a global challenge. Sometimes it is unavoidable to execute multifarious activities by a single component. In the present investigation, 6061 aluminum alloy and 304 stainless steel were joined by friction stir welding (FSW) at different tool rotational rates. Welded joints were characterized in optical and scanning electron microscopes. Reaction products in the stirring zone (SZ) were confirmed through X-ray diffraction. Joint strength was evaluated by tensile testing. It was found that the increment in average heat input and temperature at the weld nugget (WN) facilitated iron enrichment near the interface. Enhancement in the concentration of iron shifted the nature of intermetallics from the Fe2Al5 to Fe-rich end of the Fe-Al binary phase diagram. The peak microhardness and ultimate tensile strength were found to be maxima at the intermediate tool rotational rate, where Fe3Al and FeAl2 appeared along with Fe2Al5.

  13. Stainless steel recycle FY94 progress report

    SciTech Connect

    Imrich, K.J.

    1994-10-28

    The Materials Technology Section (MTS) of the Savannah River Technology Center (SRTC) was asked to demonstrate the practicality of recycling previously contaminated stainless steel components such as reactor heat exchanger heads, process water piping and slug buckets into 208 liters (55 gallon) drums and 2.8 cubic meter (100 ft{sup 3}) storage boxes. Radioactively contaminated stainless steel scrap will be sent to several industrial partners where it will be melted, decontaminated/cast into ingots, and rolled into plate and sheet and fabricated into the drums and boxes. As part of this recycle initiative, MTS was requested to demonstrate that radioactively contaminated Type 304L stainless steel could be remelted and cast to meet the applicable ASTM specification for fabrication of drums and boxes. In addition, MTS was requested to develop the technical basis of melt decontamination and establish practicality of using this approach for value added products. The findings presented in this investigation lead to the following conclusions: recycle of 18 wt% Cr-8 wt% Ni alloy can be achieved by melting Type 304 stainless steel in a air vacuum induction furnace; limited melt decontamination of the contaminated stainless steel was achieved, surface contamination was removed by standard decontamination techniques; carbon uptake in the as-cast ingots resulted from the graphite susceptor used in this experiment and is unavoidable with this furnace configuration. A new furnace optimized for melting stainless steel has been installed and is currently being tested for use in this program.

  14. Irradiation effects on 17-7 PH stainless steel, A-201 carbon steel, and titanium-6-percent-aluminum-4-percent-vanadium alloy

    NASA Technical Reports Server (NTRS)

    Hasse, R. A.; Hartley, C. B.

    1972-01-01

    Irradiation effects on three materials from the NASA Plum Brook Reactor Surveillance Program were determined. An increase of 105 K in the nil-ductility temperature for A-201 steel was observed at a fluence of approximately 3.1 x 10 to the 18th power neutrons/sq cm (neutron energy E sub n greater than 1.0 MeV). Only minor changes in the mechanical properties of 17-7 PH stainless steel were observed up to a fluence of 2 x 10 to the 21st power neutrons/sq cm (E sub n greater than 1.0 MeV). The titanium-6-percent-aluminum-4-percent-vanadium alloy maintained its notch toughness up to a fluence of 1 x 10 to the 21st power neutrons/sq cm (E sub n greater than 1.0 MeV).

  15. Nickel-based alloy/austenitic stainless steel dissimilar weld properties prediction on asymmetric distribution of laser energy

    NASA Astrophysics Data System (ADS)

    Zhou, Siyu; Ma, Guangyi; Chai, Dongsheng; Niu, Fangyong; Dong, Jinfei; Wu, Dongjiang; Zou, Helin

    2016-07-01

    A properties prediction method of Nickel-based alloy (C-276)/austenitic stainless steel (304) dissimilar weld was proposed and validated based on the asymmetric distribution of laser energy. Via the dilution level DC-276 (the ratio of the melted C-276 alloy), the relations between the weld properties and the energy offset ratio EC-276 (the ratio of the irradiated energy on the C-276 alloy) were built, and the effects of EC-276 on the microstructure, mechanical properties and corrosion resistance of dissimilar welds were analyzed. The element distribution Cweld and EC-276 accorded with the lever rule due to the strong convention of the molten pool. Based on the lever rule, it could be predicted that the microstructure mostly consists of γ phase in each weld, the δ-ferrite phase formation was inhibited and the intermetallic phase (P, μ) formation was promoted with the increase of EC-276. The ultimate tensile strength σb of the weld joint could be predicted by the monotonically increasing cubic polynomial model stemming from the strengthening of elements Mo and W. The corrosion potential U, corrosion current density I in the active region and EC-276 also met the cubic polynomial equations, and the corrosion resistance of the dissimilar weld was enhanced with the increasing EC-276, mainly because the element Mo could help form a steady passive film which will resist the Cl- ingress.

  16. Metal release from stainless steel powders and massive sheets--comparison and implication for risk assessment of alloys.

    PubMed

    Hedberg, Yolanda; Mazinanian, Neda; Odnevall Wallinder, Inger

    2013-02-01

    Industries that place metal and alloy products on the market are required to demonstrate that they are safe for all intended uses, and that any risks to humans, animals or the environment are adequately controlled. This requires reliable and robust in vitro test procedures. The aim of this study is to compare the release of alloy constituents from stainless steel powders of different grades (focus on AISI 316L) and production routes into synthetic body fluids with the release of the same metals from massive sheets in relation to material and surface characteristics. The comparison is justified by the fact that the difference between massive surfaces and powders from a metal release/dissolution and surface perspective is not clearly elucidated within current legislations. Powders and abraded and aged (24 h) massive sheets were exposed to synthetic solutions of relevance for biological settings and human exposure routes, for periods of up to one week. Concentrations of released iron, chromium, nickel, and manganese in solution were measured, and the effect of solution pH, acidity, complexation capacity, and proteins elucidated in relation to surface oxide composition and its properties. Implications for risk assessments based on in vitro metal release data from alloys are elucidated.

  17. Effect of Alloying Additions on Phase Equilibria and Creep Resistance of Alumina-Forming Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Yamamoto, Y.; Santella, M. L.; Brady, M. P.; Bei, H.; Maziasz, P. J.

    2009-08-01

    The high-temperature creep properties of a series of alumina-forming austenitic (AFA) stainless steels based on Fe-20Ni-(12-14)Cr-(2.5-4)Al-(0.2-3.3)Nb-0.1C (weight percent) were studied. Computational thermodynamics were used to aid in the interpretation of data on microstructural stability, phase equilibria, and creep resistance. Phases of MC (M: mainly Nb), M23C6 (M: mainly Cr), B2 [ β-(Ni,Fe)Al], and Laves [Fe2(Mo,Nb)] were observed after creep-rupture testing at 750 °C and 170 MPa; this was generally consistent with the thermodynamic calculations. The creep resistance increased with increasing Nb additions up to 1 wt pct in the 2.5 and 3 Al wt pct alloy series, due to the stabilization of nanoscale MC particles relative to M23C6. Additions of Nb greater than 1 wt pct decreased creep resistance in the alloy series due to stabilization of the Laves phase and increased amounts of undissolved, coarse MC, which effectively reduced the precipitation of nanoscale MC particles. The additions of Al also increased the creep resistance moderately due to the increase in the volume fraction of B2 phase precipitates. Calculations suggested that optimum creep resistance would be achieved at approximately 1.5 wt pct Nb in the 4 wt pct Al alloy series.

  18. Effect of alloying additions on phase equilibria and creep resistance of alumina-forming austenitic stainless steels

    SciTech Connect

    Yamamoto, Yukinori; Santella, Michael L; Brady, Michael P; Bei, Hongbin; Maziasz, Philip J

    2009-01-01

    The high-temperature creep properties of a series of alumina-forming austenitic (AFA) stainless steels based on Fe-20Ni-(12-14)Cr-(2.5-4)Al-(0.2-3.3)Nb-0.1C (weight percent) were studied. Computational thermodynamics were used to aid in the interpretation of data on microstructural stability, phase equilibria, and creep resistance. Phases of MC (M: mainly Nb), M{sub 23}C{sub 6} (M: mainly Cr), B2 [{beta}-(Ni,Fe)Al], and Laves [Fe{sub 2}(Mo,Nb)] were observed after creep-rupture testing at 750 C and 170 MPa; this was generally consistent with the thermodynamic calculations. The creep resistance increased with increasing Nb additions up to 1 wt pct in the 2.5 and 3 Al wt pct alloy series, due to the stabilization of nanoscale MC particles relative to M{sub 23}C{sub 6}. Additions of Nb greater than 1 wt pct decreased creep resistance in the alloy series due to stabilization of the Laves phase and increased amounts of undissolved, coarse MC, which effectively reduced the precipitation of nanoscale MC particles. The additions of Al also increased the creep resistance moderately due to the increase in the volume fraction of B2 phase precipitates. Calculations suggested that optimum creep resistance would be achieved at approximately 1.5 wt pct Nb in the 4 wt pct Al alloy series.

  19. Materials data handbook: Stainless steel type 301

    NASA Technical Reports Server (NTRS)

    Muraca, R. F.; Whittick, J. S.

    1972-01-01

    A summary of the materials property information for stainless steel type 301 is presented. The scope of the information includes physical and mechanical properties at cryogenic, ambient, and elevated temperatures. Information on material procurement, metallurgy of the alloy, corrosion, environmental effects, fabrication, and bonding is developed.

  20. Low-cycle fatigue of Type 347 stainless steel and Hastelloy alloy X in hydrogen gas and in air at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Jaske, C. E.; Rice, R. C.; Buchheit, R. D.; Roach, D. B.; Porfilio, T. L.

    1976-01-01

    An investigation was conducted to assess the low-cycle fatigue resistance of two alloys, Type 347 stainless steel and Hastelloy Alloy X, that were under consideration for use in nuclear-powered rocket vehicles. Constant-amplitude, strain-controlled fatigue tests were conducted under compressive strain cycling at a constant strain rate of 0.001/sec and at total axial strain ranges of 1.5, 3.0, and 5.0 %, in both laboratory-air and low-pressure hydrogen-gas environments at temperatures from 538 to 871 C. Specimens were obtained from three heats of Type 347 stainless steel bar and two heats of Hastelloy Alloy X. The tensile properties of each heat were determined at 21, 538, 649, and 760 C. The continuous cycling fatigue resistance was determined for each heat at temperatures of 538, 760, and 871 C. The Type 347 stainless steel exhibited equal or superior fatigue resistance to the Hastelloy Alloy X at all conditions of this study.

  1. Furnace brazing type 304 stainless steel to vanadium alloy (V?5Cr?5Ti)

    NASA Astrophysics Data System (ADS)

    Steward, R. V.; Grossbeck, M. L.; Chin, B. A.; Aglan, H. A.; Gan, Y.

    2000-12-01

    In this investigation, pure copper was joined to type 304 stainless steel and V-5Cr-5Ti by brazing in a high vacuum furnace. Microstructural changes in the brazed region and surrounding substrates were examined as a function of holding time at temperatures of 20°C, 40°C and 60°C above the melting point of copper. Reaction layers, which were extremely brittle, formed between the Cu and V-5Cr-5Ti substrates. The formation of intermetallic phases at the filler metal/substrate interfaces was evaluated. Additionally, precipitates (FeCu 2 and FeCu 18) formed in the Cu rich filler region. For temperatures ⩾60°C above the melting point of Cu, extensive transverse cracking was observed. Hardness tests substantiated the hypothesis that the Cu/V-5Cr-5Ti reaction layer was extremely brittle, since micro-cracks propagated from the tips of the diamond-shaped indentations. Results of mechanical properties tests of the brazed material are also presented.

  2. Microstructure and Interfacial Reactions During Vacuum Brazing of Stainless Steel to Titanium Using Ag-28 pct Cu Alloy

    NASA Astrophysics Data System (ADS)

    Laik, A.; Shirzadi, A. A.; Sharma, G.; Tewari, R.; Jayakumar, T.; Dey, G. K.

    2015-02-01

    Microstructural evolution and interfacial reactions during vacuum brazing of grade-2 Ti and 304L-type stainless steel (SS) using eutectic alloy Ag-28 wt pct Cu were investigated. A thin Ni-depleted zone of -Fe(Cr, Ni) solid solution formed on the SS-side of the braze zone (BZ). Cu from the braze alloy, in combination with the dissolved Fe and Ti from the base materials, formed a layer of ternary compound , adjacent to Ti in the BZ. In addition, four binary intermetallic compounds, CuTi, CuTi, CuTi and CuTi formed as parallel contiguous layers in the BZ. The unreacted Ag solidified as islands within the layers of CuTi and CuTi. Formation of an amorphous phase at certain locations in the BZ could be revealed. The -Ti(Cu) layer, formed due to diffusion of Cu into Ti-based material, transformed to an -Ti + CuTi eutectoid with lamellar morphology. Tensile test showed that the brazed joints had strength of 112 MPa and failed at the BZ. The possible sequence of events that led to the final microstructure and the mode of failure of these joints were delineated.

  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

    micron 2219 Aluminum particles as the projectiles. Monel proved superior as Porter was unable to ignite Monel, but was able to icnite AISI 304L CRES with...800 micron 2219 Aluminum particles in the high velocity test appratus (see Figure 3.10). 2. Friction Tribology has been studied as a method of...Monel 400 Copper 102 Aluminum 6061- T6 1015 Carbon Steel Inconel 600 Hastelloy X Inconel718 440C Stainless Steel 17-4 PH Stainless Steel Invar 36 Brass 360

  4. Welding tritium exposed stainless steel

    SciTech Connect

    Kanne, W.R. Jr.

    1994-11-01

    Stainless steels that are exposed to tritium become unweldable by conventional methods due to buildup of decay helium within the metal matrix. With longer service lives expected for tritium containment systems, methods for welding on tritium exposed material will become important for repair or modification of the systems. Solid-state resistance welding and low-penetration overlay welding have been shown to mitigate helium embrittlement cracking in tritium exposed 304 stainless steel. These processes can also be used on stainless steel containing helium from neutron irradiation, such as occurs in nuclear reactors.

  5. Effect of Sintering Atmosphere and Solution Treatment on Density, Microstructure and Tensile Properties of Duplex Stainless Steels Developed from Pre-alloyed Powders

    NASA Astrophysics Data System (ADS)

    Murali, Arun Prasad; Mahendran, Sudhahar; Ramajayam, Mariappan; Ganesan, Dharmalingam; Chinnaraj, Raj Kumar

    2017-01-01

    In this research, Powder Metallurgy (P/M) of Duplex Stainless Steels (DSS) of different compositions were prepared through pre-alloyed powders and elemental powders with and without addition of copper. The powder mix was developed by pot mill for 12 h to obtain the homogeneous mixture of pre-alloyed powder with elemental compositions. Cylindrical green compacts with the dimensions of 30 mm diameter and 12 mm height were compacted through universal testing machine at a pressure level of 560 ± 10 MPa. These green compacts were sintered at 1350 °C for 2 h in hydrogen and argon atmospheres. Some of the sintered stainless steel preforms were solution treated at 1050 °C followed by water quenching. The sintered as well as solution treated samples were analysed by metallography examination, Scanning Electron Microscopy and evaluation of mechanical properties. Ferrite content of sintered and solution treated DSS were measured by Fischer Ferritoscope. It is inferred that the hydrogen sintered DSS depicted better density (94% theoretical density) and tensile strength (695 MPa) than the argon sintered steels. Similarly the microstructure of solution treated DSS revealed existence of more volume of ferrite grains than its sintered condition. Solution treated hydrogen sintered DSS A (50 wt% 316L + 50 wt% 430L) exhibited higher tensile strength of 716 MPa and elongation of 17%, which are 10-13% increment than the sintered stainless steels.

  6. Microstructure Evolution During Stainless Steel-Copper Vacuum Brazing with a Ag/Cu/Pd Filler Alloy: Effect of Nickel Plating

    NASA Astrophysics Data System (ADS)

    Choudhary, R. K.; Laik, A.; Mishra, P.

    2017-02-01

    Vacuum brazing of stainless steel and copper plates was done using a silver-based filler alloy. In one set of experiments, around 30-µm-thick nickel coatings were electrochemically applied on stainless steel plates before carrying out the brazing runs and its effect in making changes in the braze-zone microstructure was studied. For brazing temperature of 830 °C, scanning electron microscopy examination of the braze-zone revealed that relatively sound joints were obtained when brazing was done with nickel-coated stainless steel than with uncoated one. However, when brazing of nickel-coated stainless steel and copper plates was done at 860 °C, a wide crack appeared in the braze-zone adjacent to copper side. Energy-dispersive x-ray analysis and electron microprobe analysis confirmed that at higher temperature, the diffusion of Cu atoms from copper plate towards the braze-zone was faster than that of Ni atoms from nickel coating. Helium leak rate of the order 10-11 Pa m3/s was obtained for the crack-free joint, whereas this value was higher than 10-4 Pa m3/s for the joint having crack. The shear strength of the joint was found to decrease considerably due to the presence of crack.

  7. Microstructure Evolution During Stainless Steel-Copper Vacuum Brazing with a Ag/Cu/Pd Filler Alloy: Effect of Nickel Plating

    NASA Astrophysics Data System (ADS)

    Choudhary, R. K.; Laik, A.; Mishra, P.

    2017-03-01

    Vacuum brazing of stainless steel and copper plates was done using a silver-based filler alloy. In one set of experiments, around 30-µm-thick nickel coatings were electrochemically applied on stainless steel plates before carrying out the brazing runs and its effect in making changes in the braze-zone microstructure was studied. For brazing temperature of 830 °C, scanning electron microscopy examination of the braze-zone revealed that relatively sound joints were obtained when brazing was done with nickel-coated stainless steel than with uncoated one. However, when brazing of nickel-coated stainless steel and copper plates was done at 860 °C, a wide crack appeared in the braze-zone adjacent to copper side. Energy-dispersive x-ray analysis and electron microprobe analysis confirmed that at higher temperature, the diffusion of Cu atoms from copper plate towards the braze-zone was faster than that of Ni atoms from nickel coating. Helium leak rate of the order 10-11 Pa m3/s was obtained for the crack-free joint, whereas this value was higher than 10-4 Pa m3/s for the joint having crack. The shear strength of the joint was found to decrease considerably due to the presence of crack.

  8. Nanostructured nickel-free austenitic stainless steel/hydroxyapatite composites.

    PubMed

    Tulinski, Maciej; Jurczyk, Mieczyslaw

    2012-11-01

    In this work Ni-free austenitic stainless steels with nanostructure and their nanocomposites with hydroxyapatite are presented and characterized by means of X-ray diffraction and optical profiling. The samples were synthesized by mechanical alloying, heat treatment and nitriding of elemental microcrystalline powders with addition of hydroxyapatite (HA). In our work we wanted to introduce into stainless steel hydroxyapatite ceramics that have been intensively studied for bone repair and replacement applications. Such applications were chosen because of their high biocompatibility and ability to bond to bone. Since nickel-free austenitic stainless steels seem to have better mechanical properties, corrosion resistance and biocompatibility compared to 316L stainless steels, it is possible that composite made of this steel and HA could improve properties, as well. Mechanical alloying and nitriding are very effective technologies to improve the corrosion resistance of stainless steel. Similar process in case of nanocomposites of stainless steel with hydroxyapatite helps achieve even better mechanical properties and corrosion resistance. Hence nanocrystalline nickel-free stainless steels and nickel-free stainless steel/hydroxyapatite nanocomposites could be promising bionanomaterials for use as a hard tissue replacement implants, e.g., orthopedic implants. In such application, the surface roughness and more specifically the surface topography influences the proliferation of cells (e.g., osteoblasts).

  9. CRADA NFE-08-01456 Evaluation of Alumina-Forming Austenitic Stainless Steel Alloys in Industrial Gas Turbines

    SciTech Connect

    Brady, Michael P; Pint, Bruce A; Unocic, Kinga A; Yamamoto, Yukinori; Kumar, Deepak; Lipschutz, Mark D.

    2011-09-01

    Oak Ridge National Laboratory (ORNL) and Solar Turbines Incorporated (Solar) participated in an in-kind cost share cooperative research and development agreement (CRADA) effort under the auspices of the Energy Efficiency and Renewable Energy (EERE) Technology Maturation Program to explore the feasibility for use of developmental ORNL alumina-forming austenitic (AFA) stainless steels as a material of construction for industrial gas turbine recuperator components. ORNL manufactured lab scale foil of three different AFA alloy compositions and delivered them to Solar for creep properties evaluation. One AFA composition was selected for a commercial trial foil batch. Both lab scale and the commercial trial scale foils were evaluated for oxidation and creep behavior. The AFA foil exhibited a promising combination of properties and is of interest for future scale up activities for turbine recuperators. Some issues were identified in the processing parameters used for the first trial commercial batch. This understanding will be used to guide process optimization of future AFA foil material production.

  10. High Mn austenitic stainless steel

    DOEpatents

    Yamamoto, Yukinori [Oak Ridge, TN; Santella, Michael L [Knoxville, TN; Brady, Michael P [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN; Liu, Chain-tsuan [Knoxville, TN

    2010-07-13

    An austenitic stainless steel alloy includes, in weight percent: >4 to 15 Mn; 8 to 15 Ni; 14 to 16 Cr; 2.4 to 3 Al; 0.4 to 1 total of at least one of Nb and Ta; 0.05 to 0.2 C; 0.01 to 0.02 B; no more than 0.3 of combined Ti+V; up to 3 Mo; up to 3 Co; up to 1W; up to 3 Cu; up to 1 Si; up to 0.05 P; up to 1 total of at least one of Y, La, Ce, Hf, and Zr; less than 0.05 N; and base Fe, wherein the weight percent Fe is greater than the weight percent Ni, and wherein the alloy forms an external continuous scale including alumina, nanometer scale sized particles distributed throughout the microstructure, the particles including at least one of NbC and TaC, and a stable essentially single phase FCC austenitic matrix microstructure that is essentially delta-ferrite-free and essentially BCC-phase-free.

  11. Properties of cryogenically worked metals. [stainless steels

    NASA Technical Reports Server (NTRS)

    Schwartzberg, F. R.; Kiefer, T. F.

    1975-01-01

    A program was conducted to determine whether the mechanical properties of cryogenically worked 17-7PH stainless steel are suitable for service from ambient to cryogenic temperatures. It was determined that the stress corrosion resistance of the cryo-worked material is quite adequate for structural service. The tensile properties and fracture toughness at room temperature were comparable to titanium alloy 6Al-4V. However, at cryogenic temperatures, the properties were not sufficient to recommend consideration for structural service.

  12. Pitting corrosion resistant austenite stainless steel

    DOEpatents

    van Rooyen, D.; Bandy, R.

    A pitting corrosion resistant austenite stainless steel comprises 17 to 28 wt. % chromium, 15 to 26 wt. % nickel, 5 to 8 wt. % molybdenum, and 0.3 to 0.5 wt. % nitrogen, the balance being iron, unavoidable impurities, minor additions made in the normal course of melting and casting alloys of this type, and may optionally include up to 10 wt. % of manganese, up to 5 wt. % of silicon, and up to 0.08 wt. % of carbon.

  13. Braze alloy spreading on steel

    NASA Technical Reports Server (NTRS)

    Siewert, T. A.; Heine, R. W.; Lagally, M. G.

    1978-01-01

    Scanning electron microscopy (SEM) and Auger electron microscopy (AEM) were employed to observe elemental surface decomposition resulting from the brazing of a copper-treated steel. Two types of steel were used for the study, stainless steel (treated with a eutectic silver-copper alloy), and low-carbon steel (treated with pure copper). Attention is given to oxygen partial pressure during the processes; a low enough pressure (8 x 10 to the -5th torr) was found to totally inhibit the spreading of the filler material at a fixed heating cycle. With both types of steel, copper treatment enhanced even spreading at a decreased temperature.

  14. Coupled Multi-Electrode Investigation of Crevice Corrosion of 316 Stainless Steel and NiCrMo Alloy 625

    SciTech Connect

    F. Bocher; F.J. Presuel-Moreno; J.R. Scully

    2006-06-08

    the position where the potential drops to E{sub Flade}. Figure 1 illustrates the resulting x{sub crit} vs. G scaling laws for 316 Stainless Steel in 1 M HCl at 50 C. The coupled multi-wire array is composed of one hundred identical 316 Stainless Steel wires in a five by twenty formation inserted in a groove of a 316 Stainless Steel rod such that the ends of the wires are flush mounted with the rod. The 100 wires are coupled electrically through in-line zero resistance ammeters. The diameter of the wires (250 {micro}m) was chosen so that x{sub crit} (critical initiation distance from the crevice mouth) and the expected zone of crevice corrosion (predicted from the scaling law) would be larger than the radius of a single wire. The array created a flush mounted planar electrode with the surface/volume ratio obtained in planar crevices. The observation of the current evolution as a function of position inside and outside the crevice as function of time was made possible as illustrated in Figure 2 in 0.6 M NaCl at 50 C.

  15. The electroplated Pd-Co alloy film on 316 L stainless steel and the corrosion resistance in boiling acetic acid and formic acid mixture with stirring

    NASA Astrophysics Data System (ADS)

    Li, Sirui; Zuo, Yu; Tang, Yuming; Zhao, Xuhui

    2014-12-01

    Pd-Co alloy films were deposited on 316 L stainless steel by electroplating. Scanning electronic microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, weight loss test and polarization test were used to determine the properties of the Pd-Co alloy films. The Pd-Co films show fine grain size, low porosity and obviously high micro-hardness. The Co content in the film can be controlled in a large range from 21.9 at.% to 57.42 at.%. Pd is rich on the Pd-Co film surface, which is benefit to increase the corrosion resistance. In boiling 90% acetic acid plus 10% formic acid mixture with 0.005 M Br- under stirring, the Pd-Co plated stainless steel samples exhibit evidently better corrosion resistance in contrast to Pd plated samples. The good corrosion resistance of the Pd-Co alloy film is explained by the better compactness, the lower porosity, and the obviously higher micro-hardness of the alloy films, which increases the resistance to erosion and retards the development of micro-pores in the film.

  16. Long term high temperature oxidation characteristics of La and Cu alloyed ferritic stainless steels for solid oxide fuel cell interconnects

    NASA Astrophysics Data System (ADS)

    Swaminathan, Srinivasan; Lee, Young-Su; Kim, Dong-Ik

    2016-09-01

    To ensure the best performance of solid oxide fuel cell metallic interconnects, the Fe-22 wt.% Cr ferritic stainless steels with various La contents (0.006-0.6 wt.%) and Cu addition (1.57 wt.%), are developed. Long-term isothermal oxidation behavior of these steels is investigated in air at 800 °C, for 2700 h. Chemistry, morphology, and microstructure of the thermally grown oxide scale are examined using XPS, SEM-EDX, and XRD techniques. Broadly, all the steels show a double layer consisting of an inner Cr2O3 and outer (Mn, Cr)3O4. Distinctly, in the La-added steels, binary oxides of Cr, Mn and Ti are found at the oxide scale surface together with (Mn, Cr)3O4. Furthermore, all La-varied steels possess the metallic Fe protrusions along with discontinuous (Mn, Cr)3O4 spinel zones at the oxide scale/metal interface and isolated precipitates of Ti-oxides in the underlying matrix. Increase of La content to 0.6 wt.% is detrimental to the oxidation resistance. For the Cu-added steel, Cu is found to segregate strongly at the oxide scale/metal interface which inhibits the ingress of oxygen thereby suppressing the subscale formation of (Mn, Cr)3O4. Thus, Cu addition to the Fe-22Cr ferritic stainless steels benefits the oxidation resistance.

  17. Pitting corrosion of low-Cr austenitic stainless steels

    SciTech Connect

    Bullard, Sophie J.; Covino, Bernard S. Jr.

    1996-01-01

    The Albany Research Center has investigated the pitting corrosion resistance of experimental low-Cr stainless steels and several commercial stainless steels in chloride-containing aqueous and atmospheric environments. Previous research had shown the experimental alloys to be as corrosion resistant as commercial stainless steels in chloride-free acid environments. The alloys studied were Fe-8Cr-16Ni-5.5Si-1Cu-(0-1)Mo, 304 SS, and 316 SS. These alloys were examined by immersion and electrochemical tests in 3.5 wt. pct. NaCl and 6 wt.pct.FeCl{sub 3}. Results of these tests showed that the addition of one weight percent Mo improved the pitting resistance of the low-Cr alloy and that the Mo-containing experimental alloy was as resistant to pitting as the commercial alloys. Electrochemical tests did, however, show the experimental alloys to be slightly less resistant to pitting than the commercial alloys. Because of these results, the low-Cr alloy with one weight percent Mo and 304 SS were exposed for one year to a marine atmospheric environment on the coast of Oregon. The marine atmospheric corrosion resistance of the low-Cr alloy was found to be comparable to that for type 304 stainless steel.

  18. Nickel release from stainless steels.

    PubMed

    Haudrechy, P; Mantout, B; Frappaz, A; Rousseau, D; Chabeau, G; Faure, M; Claudy, A

    1997-09-01

    In 1994, a study of nickel release and allergic contact dermatitis from nickel-plated metals and stainless steels was published in this journal. It was shown that low-sulfur stainless steel grades like AISI 304, 316L or 430 (S < or = 0.007%) release less than 0.03 microgram/cm2/week of nickel in acid artificial sweat and elicit no reactions in patients already sensitized to nickel. In contrast, nickel-plated samples release around 100 micrograms/cm2/week of Ni and high-sulfur stainless steel (AISI 303-S approximately 0.3%) releases about 1.5 micrograms/cm2/week in this acid artificial sweat. Applied on patients sensitized to nickel, these metals elicit positive reactions in 96% and 14%, respectively, of the patients. The main conclusion was that low-sulfur stainless steels like AISI 304, 316L or 430, even when containing Ni, should not elicit nickel contact dermatitis, while metals having a mean corrosion resistance like a high-sulfur stainless steel (AISI 303) or nickel-plated steel should be avoided. The determining characteristic was in fact the corrosion resistance in chloride media, which, for stainless steels, is connected, among other factors, to the sulfur content. Thus, a question remained concerning the grades with an intermediate sulfur content, around 0.03%, which were not studied. They are the object of the study presented in this paper. 3 tests were performed: leaching experiments, dimethylglyoxime and HNO3 spot tests, and clinical patch tests; however, only stainless steels were tested: a low-sulfur AISI 304 and AISI 303 as references and 3 grades with a sulfur content around 0.03%: AISI 304L, AISI 304L added with Ca, AISI 304L+Cu. Leaching experiments showed that the 4 non-resulfurised grades released less than 0.5 microgram/cm2/week in acid sweat while the reulfurized AISI 303 released around or more than 0.5 microgram/cm2/week. This is explained by the poorer corrosion resistance of the resulfurized grade. Yet all these grades had the same

  19. Cast, heat-resistant austenitic stainless steels having reduced alloying element content

    DOEpatents

    Muralidharan, Govindarajan [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN; Pankiw, Roman I [Greensburg, PA

    2010-07-06

    A cast, austenitic steel composed essentially of, expressed in weight percent of the total composition, about 0.4 to about 0.7 C, about 20 to about 30 Cr, about 20 to about 30 Ni, about 0.5 to about 1 Mn, about 0.6 to about 2 Si, about 0.05 to about 1 Nb, about 0.05 to about 1 W, about 0.05 to about 1.0 Mo, balance Fe, the steel being essentially free of Ti and Co, the steel characterized by at least one microstructural component selected from the group consisting of MC, M.sub.23C.sub.6, and M(C, N).

  20. Cast, heat-resistant austenitic stainless steels having reduced alloying element content

    DOEpatents

    Muralidharan, Govindarajan [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN; Pankiw, Roman I [Greensburg, PA

    2011-08-23

    A cast, austenitic steel composed essentially of, expressed in weight percent of the total composition, about 0.4 to about 0.7 C, about 20 to about 30 Cr, about 20 to about 30 Ni, about 0.5 to about 1 Mn, about 0.6 to about 2 Si, about 0.05 to about 1 Nb, about 0.05 to about 1 W, about 0.05 to about 1.0 Mo, balance Fe, the steel being essentially free of Ti and Co, the steel characterized by at least one microstructural component selected from the group consisting of MC, M.sub.23C.sub.6, and M(C, N).

  1. Subcascade formation ratio in neutron-irradiated stainless steels

    NASA Astrophysics Data System (ADS)

    Yoshiie, T.; Satoh, Y.; Huang, S. S.; Horiki, M.; Sato, K.; Xu, Q.

    2016-01-01

    High-energy-particle irradiation in metals produces cascade damage. If the particle energy is high enough, a cascade is divided into subcascades. In each subcascade, a vacancy rich area is surrounded by an interstitial area. Vacancy clusters are expected to form directly in the vacancy rich area. In this study, the vacancy cluster formation ratio in subcascades was estimated by positron annihilation lifetime spectroscopy and transmission electron microscopy in commercial stainless steels and their model alloys. The vacancy cluster formation ratio was 1.7×10-3 and 9.1×10-5 in austenitic stainless steel and ferritic/martensitic stainless steel, respectively

  2. The Corrosion Behavior of Stainless Steels and Copper Alloys Exposed to Natural Seawater

    DTIC Science & Technology

    1991-01-01

    significant changes of the corrosion potential (Ecw) or surface properties. Rotating cylinder experiments indicated that both E., and corrosion rates for...and inorganic chloride corrosion layer that contained alloying elements; a biof ilm; and crystalline, spherical phosphate-rich deposits. All copper...nichtrostendem Stahl und bacteria and diatoms that did not cause significant changes of the Titan entstehenden dfinnen Biofilme bestanden aus

  3. Impact tests of the tungsten coated stainless steels prepared by using magnetron sputtering with ion beam mixing or electron beam alloying treatment

    NASA Astrophysics Data System (ADS)

    Zou, Yu; Zhan, Chang-Yong; Yang, Bin; Wu, Jian-Chun

    2013-05-01

    Tungsten films were deposited on stainless steel (SS) with ion beam mixing (IBM) or electron beam alloying (EBA) treatment. The ductile-brittle transition behaviors of the specimens were investigated by means of instrumented Charpy impact test at a series of temperature, and SEM was used to observe the morphology of the cross section. Impact tests show that different treatment methods with W films do not have much influence on crack initiation, while EBA treatment with W films can more effectively prevent crack propagation, namely improve the impact toughness of SS than using IBM treatment. The reason that caused this difference was discussed.

  4. Possibility of Multi-material Laser Cladding Fabrication of Nickel Alloy and Stainless Steel

    NASA Astrophysics Data System (ADS)

    Kotoban, D.; Aramov, A.; Tarasova, T.

    There are some applications in the industry for multi-material components, including device engineering and multifunctional surface engineering, having to eliminate a brazing or welding technological step. This study investigates the laser cladding process parameters, related single track geometry and quality of multi-material samples. The optimal process parameters for steel were found of 0.21-0.26 J/mm2 and 0.25 10-2 g/mm under the scanning velocity of 1400-1700 mm/min and powder feeding of 4.2-4.5 g/min. The bimetal thin walls, cylinders and cubes were manufactured within the optimal conditions. The requirements of steel and nickel joining were explored. For the examination, the optical microscopy, SEM, EDX microelement analysis and hardness analysis were involved.

  5. The influence of cooling rate on the microstructure of stainless steel alloys

    SciTech Connect

    Elmer, J.W.

    1988-09-01

    The emergence of high energy density welding, laser surface modification and rapid solidification as commonly used metallurgical processing techniques has greatly increased the range of cooling rates that can be accessed during the solidification of metals and alloys. The microstructures which develop during these rapid cooling conditions may be significantly different from those which develop during low cooling rate conditions as the result of access to new metastable phases with the additional kinetic limitations that accompany rapid solidification. This investigation explores the influence of cooling rate on a series of seven ternary alloys which span the line of two-fold saturation in the Fe-Ni-Cr system. High speed electron beam surface melting was used to resolidify these alloys at scan speeds up to 5 m/s. The resulting cooling rates were estimated from dendrite arm spacing measurements and were confirmed by heat flow modeling to vary from 7 /times/ 10/sup 0/ /degree/C/s to 8 /times/ 10/sup 6/ /degree/C/s. The microstructures that developed from each solidification condition were examined using optical metallography, electron microprobe analysis, scanning electron microscopy and a vibrating sample magnetometer. These results were used to create diagrams to predict the primary mode of solidification, the ferrite content and the complex microstructural morphologies which develop as a function of interface velocity and composition. 158 refs., 90 figs., 45 tabs.

  6. X-ray fluorescence analysis of alloy and stainless steels using a mercuric iodide detector

    NASA Technical Reports Server (NTRS)

    Kelliher, Warren C.; Maddox, W. Gene

    1988-01-01

    A mercuric iodide detector was used for the XRF analysis of a number of NBS standard steels, applying a specially developed correction method for interelemental effects. It is shown that, using this method and a good peak-deconvolution technique, the HgI2 detector is capable of achieving resolutions and count rates needed in the XRF anlysis of multielement samples. The freedom from cryogenic cooling and from power supplies necessary for an electrically cooled device makes this detector a very good candidate for a portable instrument.

  7. Global stainless steel cycle exemplifies China's rise to metal dominance.

    PubMed

    Reck, Barbara K; Chambon, Marine; Hashimoto, Seiji; Graedel, T E

    2010-05-15

    The use of stainless steel, a metal employed in a wide range of technology applications, has been characterized for 51 countries and the world for the years 2000 and 2005. We find that the global stainless steel flow-into-use increased by more than 30% in that 5 year period, as did additions to in-use stocks. This growth was mainly driven by China, which accounted for almost half of the global growth in stainless steel crude production and which tripled its flow into use between 2000 and 2005. The global stainless steel-specific end-of-life recycling rate increased from 66% (2000) to 70% (2005); the landfilling rate was 22% for both years, and 9% (2000) to 12% (2005) was lost into recycled carbon and alloy steels. Within just 5 years, China passed such traditionally strong stainless steel producers and users as Japan, USA, Germany, and South Korea to become the dominant player of the stainless steel industry. However, China did not produce any significant stainless steel end-of-life flows in 2000 or 2005 because its products-in-use are still too new to require replacements. Major Chinese discard flows are expected to begin between 2015 and 2020.

  8. 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.

  9. Thermal Linear Expansion of Nine Selected AISI Stainless Steels

    DTIC Science & Technology

    1978-04-01

    stainless steels. The nine selected stainless steels are AISI 303, 304, 304L, 316, 317, 321, 347, 410 , and 430. The recoended values Include the...point of the stainless steels. The nine selected stainless steels are AISI 303, 304, 304L, 316, 317, 321, 347, 410 , and 430. The recommended values...Stainless Steel..................................26 8. AISI 410 Stainless Steel..................................29 9. AISI 430 Stainless Steel

  10. The Effect of Nb and S Segregation on the Solidification Cracking of Alloy 52M Weld Overlay on CF8 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Chu, H. A.; Young, M. C.; Chu, H. C.; Tsay, L. W.; Chen, C.

    2014-03-01

    The weld overlay of Alloy 52M (a nickel-based filler metal) on a cast 304 (CF8) stainless steel (SS) was made to simulate overlay welding of the safe end of reactor pressure vessels in nuclear power plants. The deteriorated effect of sulfur on solidification cracking of the Alloy 52M overlay was highlighted by using a CF8 substrate with 0.14 wt.% S. Severe solidification cracking was observed when Alloy 52M was directly overlaid on the CF8 substrate. To lower the cracking susceptibility, ER 308L was deposited on the CF8 SS as a buffer layer before the subsequent deposition of Alloy 52M. Under such circumstances, the region near the weld interface between the SS buffer layer and Alloy 52M overlay was susceptible to solidification cracking. The formation of γ-NbC(N), γ-Laves, and γ-(Fe-Ni-S) eutectic-type constituents at the solidification boundaries was responsible for cracking near the weld interface. Nevertheless, depositing two layers of 308L prior to applying Alloy 52M could effectively reduce the cracking susceptibility of the overlay.

  11. Modeling of Crevice Corrosion Stability of a NiCrMo Alloy and Stainless Steel

    SciTech Connect

    F.J. Presuel-Moreno; F. Bocher; J.R. Scully; R.G. Kelly

    2006-05-19

    Damage of structural significance from crevice corrosion of corrosion resistant alloys requires that at least a portion of the creviced area remain active over a sufficiently long period. Stifling results shen the aggressive chemistry required inside the crevice to keep the material depassivated, i.e., actively corroding, cannot be maintained. This loss of critical chemistry occurs when the rate of mass transport out of the crevice exceeds the rate of dissolution and subsequent hydrolysis of metal ions inside the crevice. For the treatment considered here, the mass transport conditions are constant for a given geometry and potential. What then controls the stability of the internal chemistry is the interaction between the electrochemical kinetics at the interface and the crevice chemistry composition. This work focuses on the parameters that control the stability of crevice corrosion by modeling the evolution of the chemical and electrochemical conditions within a crevice open only at one end (e.g. the mouth) in which the entire crevice is initially filled with the Critical Chemistry Solution (CCS) or filled with chemistries slightly less or more aggressive than the CCS. The crevice mouth is in contact with a weak acid solution (pH 3) that provides the boundary conditions at the crevice mouth. The potential at the mouth was held constant at +0.1 V{sub sce} in most instances with selected cases held at 0.0 V{sub sce}. The material selected was Ni-22Cr-6Mo alloy. The electrochemical kinetics at the pH values of interest have been recently characterized via potentiodynamic polarization. Figure 1 shows the polarization curves for Ni-22Cr-6Mo samples tested at room temperature in various HCl solutions. These data were used in all calculations. That is as the pH changed, a new polarization curve was applied to the position in the crevice. E, pH was calculated at each position and from this data, current at each position was determined. The effects of the crevice gap and

  12. Dislocation substructure in fatigued duplex stainless steel

    SciTech Connect

    Polak, J. . Lab. de Mecanique de Lille Inst. of Physical Metallurgy, Brno . Academy of Sciences); Degallaix, S. . Lab. de Mecanique de Lille); Kruml, T. . Academy of Sciences)

    1993-12-15

    Cyclic plastic straining of crystalline materials results in the formation of specific dislocation structures. Considerable progress in mapping and understanding internal dislocation structures has been achieved by studying single crystal behavior: however, most structural materials have a polycrystalline structure and investigations of polycrystals in comparison to single crystal behavior of simple metals prove to be very useful in understanding more complex materials. There are some classes of materials, however, with complicated structure which do not have a direct equivalent in single crystalline form. Moreover, the specific dimensions and shapes of individual crystallites play an important role both in the cyclic stress-strain response of these materials and in the formation of their interior structure in cyclic straining. Austenitic-ferritic duplex stainless steel, which is a kind of a natural composite, is a material of this type. The widespread interest in the application of duplex steels is caused by approximately doubled mechanical properties and equal corrosion properties, when compared with classical austenitic stainless steels. Fatigue resistance of these steels as well as the surface damage evolution in cyclic straining have been studied; however, much less is known about the internal substructure development in cyclic straining. In this study the dislocation arrangement in ferritic and austenitic grains of the austenitic-ferritic duplex steel alloyed with nitrogen and cyclically strained with two strain amplitudes, is reported and compared to the dislocation arrangement found in single and polycrystals of austenitic and ferritic materials of a similar composition and with the surface relief produced in cyclic plastic straining.

  13. Effect of bacterial biofilm on corrosion of galvanically coupled aluminum and stainless steel alloys under conditions simulating wet storage of spent nuclear fuel

    SciTech Connect

    Zhang, H.J.; Dirk, W.J.; Geesey, G.G.

    1999-10-01

    Galvanic corrosion is a concern during wet storage of spent nuclear fuels when aluminum alloys used as cladding for nuclear fuel rods become coupled to stainless steel alloys used as materials for construction of fuel rod hangers and containment equipment. A larger galvanic current density was observed between coupled UNS A96061 and UNS S30400 electrodes submerged in autoclave-sterilized makeup water. The differences were attributed to the development of a discontinuous bacterial biofilm on the couples submerged in as-received makeup water, which was not evident on the control couples that contained several orders of magnitude lower densities of bacteria. While pitting corrosion was observed on the UNS A96061 electrodes containing high or low densities of bacteria, maximum pit depth on the electrodes with high bacterial densities was twice that measured on electrodes with low bacterial densities.

  14. Oxidation of Slurry Aluminide Coatings on Cast Stainless Steel Alloy CF8C-Plus at 800oC in Water Vapor

    SciTech Connect

    Haynes, James A; Armstrong, Beth L; Dryepondt, Sebastien N; Kumar, Deepak; Zhang, Ying

    2013-01-01

    A new, cast austenitic stainless steel, CF8C-Plus, has been developed for a wide range of high temperature applications, including diesel exhaust components, turbine casings and turbocharger housings. CF8C-Plus offers significant improvements in creep rupture life and creep rupture strength over standard CF8C steel. However, at higher temperatures and in more aggressive environments, such as those containing significant water vapor, an oxidation-resistant protective coating will be necessary. The oxidation behavior of alloys CF8C and CF8C-Plus with various aluminide coatings were compared at 800oC in air plus 10 vol% water vapor. Due to their affordability, slurry aluminides were the primary coating system of interest, although chemical vapor deposition (CVD) and pack cementation coatings were also compared. Additionally, a preliminary study of the low cycle fatigue behavior of aluminized CF8C-Plus was conducted at 800oC. Each type of coating provided substantial improvements in oxidation behavior, with simple slurry aluminides showing very good oxidation resistance after 4,000 h testing in water vapor. Preliminary low cycle fatigue results indicated that thicker aluminide coatings degraded high temperature fatigue properties of CF8C-Plus, whereas thinner coatings did not. Results suggest that appropriately designed slurry aluminide coatings are a viable option for economical, long-term oxidation protection of austenitic stainless steels in water vapor.

  15. Cast Stainless Steel Ferrite and Grain Structure

    SciTech Connect

    Ruud, Clayton O.; Ramuhalli, Pradeep; Meyer, Ryan M.; Mathews, Royce; Diaz, Aaron A.; Anderson, Michael T.

    2012-09-01

    In-service inspection requirements dictate that piping welds in the primary pressure boundary of light-water reactors be subject to a volumetric examination based on the rules contained within the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI. The purpose of the inspection is the reliable detection and accurate sizing of service-induced degradation and/or material flaws introduced during fabrication. The volumetric inspection is usually carried out using ultrasonic testing (UT) methods. However, the varied metallurgical macrostructures and microstructures of cast austenitic stainless steel piping and fittings, including statically cast stainless steel and centrifugally cast stainless steel (CCSS), introduce significant variations in the propagation and attenuation of ultrasonic energy. These variations complicate interpretation of the UT responses and may compromise the reliability of UT inspection. A review of the literature indicated that a correlation may exist between the microstructure and the delta ferrite content of the casting alloy. This paper discusses the results of a recent study where the goal was to determine if a correlation existed between measured and/or calculated ferrite content and grain structure in CCSS pipe.

  16. Cast alumina forming austenitic stainless steels

    DOEpatents

    Muralidharan, Govindarajan; Yamamoto, Yukinori; Brady, Michael P

    2013-04-30

    An austenitic stainless steel alloy consisting essentially of, in terms of weight percent ranges 0.15-0.5C; 8-37Ni; 10-25Cr; 2.5-5Al; greater than 0.6, up to 2.5 total of at least one element selected from the group consisting of Nb and Ta; up to 3Mo; up to 3Co; up to 1W; up to 3Cu; up to 15Mn; up to 2Si; up to 0.15B; up to 0.05P; up to 1 total of at least one element selected from the group consisting of Y, La, Ce, Hf, and Zr; <0.3Ti+V; <0.03N; and, balance Fe, where the weight percent Fe is greater than the weight percent Ni, and wherein the alloy forms an external continuous scale comprising alumina, and a stable essentially single phase FCC austenitic matrix microstructure, the austenitic matrix being essentially delta-ferrite free and essentially BCC-phase-free. A method of making austenitic stainless steel alloys is also disclosed.

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

    SciTech Connect

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

    2014-08-15

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

  18. 77 FR 18861 - Stainless Steel Bar From Brazil, India, Japan, and Spain; Scheduling of Expedited Five-Year Reviews

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... COMMISSION Stainless Steel Bar From Brazil, India, Japan, and Spain; Scheduling of Expedited Five-Year... orders on stainless steel bar from Brazil, India, Japan, and Spain would be likely to lead to... Inc. Co., Universal Stainless & Alloy Products, Inc., and Valbruna Slater Stainless, Inc. to...

  19. Nano-composite stainless steel

    DOEpatents

    Dehoff, Ryan R.; Blue, Craig A.; Peter, William H.; Chen, Wei; Aprigliano, Louis F.

    2015-07-14

    A composite stainless steel composition is composed essentially of, in terms of wt. % ranges: 25 to 28 Cr; 11 to 13 Ni; 7 to 8 W; 3.5 to 4 Mo; 3 to 3.5 B; 2 to 2.5 Mn; 1 to 1.5 Si; 0.3 to 1.7 C; up to 2 O; balance Fe. The composition has an austenitic matrix phase and a particulate, crystalline dispersed phase.

  20. Long-term oxidation of candidate cast iron and stainless steel exhaust system alloys from 650 to 800 °C in air with water vapor

    SciTech Connect

    Brady, Michael P.; Muralidharan, Govindarajan; Leonard, Donovan .; Haynes, James A.; Weldon, R. G.; England, R. D.

    2014-08-29

    Here, the oxidation behavior of SiMo cast iron, Ni-resist D5S cast iron, cast chromia-forming austenitic stainless steels of varying Cr/Ni content based on CF8C plus, HK, and HP, and a developmental cast alumina-forming austenitic (AFA) stainless steel of interest for diesel exhaust system components were studied for up to 5000 h at 650-800 °C in air with 10% H2O. At 650 °C, the Ni-resist D5S exhibited moderately better oxidation resistance than did the SiMo cast iron. However, the D5S suffered from oxide scale spallation issues at 700 °C and higher, whereas the oxide scales formed on SiMo cast iron remained adherent from 700-800 °C despite oxide scales hundreds of microns thick. The oxidation of the SiMo cast iron exhibited unusual temperature dependence, with periods of slower oxidation kinetics at 750-800 °C compared to 650-700 °C due to continuous silica-rich scale formation at the higher temperatures. The oxidation of the cast chromia-forming austenitics trended with the level of Cr and Ni additions, with small mass losses consistent with Cr oxy-hydroxide volatilization processes for the higher 25Cr/25-35Ni HK and HP type alloys, and transition to rapid Fe-base oxide formation and scale spallation in the lower 19Cr/12Ni CF8C plus type alloy. In contrast, small positive mass changes consistent with protective alumina scale formation were observed for the cast AFA alloy under all conditions studied. Implications of these findings for diesel exhaust system components are discussed.

  1. Long-term oxidation of candidate cast iron and stainless steel exhaust system alloys from 650 to 800 °C in air with water vapor

    DOE PAGES

    Brady, Michael P.; Muralidharan, Govindarajan; Leonard, Donovan .; ...

    2014-08-29

    Here, the oxidation behavior of SiMo cast iron, Ni-resist D5S cast iron, cast chromia-forming austenitic stainless steels of varying Cr/Ni content based on CF8C plus, HK, and HP, and a developmental cast alumina-forming austenitic (AFA) stainless steel of interest for diesel exhaust system components were studied for up to 5000 h at 650-800 °C in air with 10% H2O. At 650 °C, the Ni-resist D5S exhibited moderately better oxidation resistance than did the SiMo cast iron. However, the D5S suffered from oxide scale spallation issues at 700 °C and higher, whereas the oxide scales formed on SiMo cast iron remainedmore » adherent from 700-800 °C despite oxide scales hundreds of microns thick. The oxidation of the SiMo cast iron exhibited unusual temperature dependence, with periods of slower oxidation kinetics at 750-800 °C compared to 650-700 °C due to continuous silica-rich scale formation at the higher temperatures. The oxidation of the cast chromia-forming austenitics trended with the level of Cr and Ni additions, with small mass losses consistent with Cr oxy-hydroxide volatilization processes for the higher 25Cr/25-35Ni HK and HP type alloys, and transition to rapid Fe-base oxide formation and scale spallation in the lower 19Cr/12Ni CF8C plus type alloy. In contrast, small positive mass changes consistent with protective alumina scale formation were observed for the cast AFA alloy under all conditions studied. Implications of these findings for diesel exhaust system components are discussed.« less

  2. 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.

  3. Corrosion testing of stainless steel-zirconium metal waste form.

    SciTech Connect

    Abraham, D. P.

    1998-12-14

    Stainless steel-zirconium (SS-Zr) alloys are being considered as waste forms for the disposition of metallic waste generated during the electrometallurgical treatment of spent nuclear fuel. The waste forms contain irradiated cladding hulls, components of the alloy fuel, noble metal fission products, and actinide elements. The baseline waste form is a stainless steel-15 wt% zirconium (SS-15Zr) alloy. This article presents microstructure and some of the corrosion studies being conducted on the waste form alloys. Electrochemical corrosion, immersion corrosion, and vapor hydration tests have been performed on various alloy compositions to evaluate corrosion behavior and resistance to selective leaching of simulated fission products. The SS-Zr waste forms are successful at the immobilization and retention of fission products and show potential for acceptance as high-level nuclear waste forms.

  4. Forming Limit Diagram of Titanium and Stainless Steel Alloys to Study the Formability of Hydro-Mechanical Deep Drawing Parts

    NASA Astrophysics Data System (ADS)

    Shirizly, A.

    2005-08-01

    The increase demand for stronger, lighter and economic sheet metal products, make the Hydromecanical deep drawing process lately more and more popular. The Hydromecanical process is used in almost all types of sheet metal parts from home appliances and kitchenware to automotive and aviation industries. Therefore, many common materials were tested and characterized by their ability to sustain large strains via the well known Forming Limit Diagram (FLD). The aim of this work is to examine the forming capability if the Hydromecanical process in production of hemisphere parts made of materials commonly used in the aviation and aerospace industries. Experimental procedures were carried out to assess their ductility through FLD and the Forming Limit Carve (FLC).Two type of material sheets were tested herewith for demonstrating the procedure: commercial pure titanium and stainless steel 316L. A numerical simulation of the Hydromecanical process was examined and compared to self made Hydromecanical deep drawing of hemispherical parts.

  5. Forming Limit Diagram of Titanium and Stainless Steel Alloys to Study the Formability of Hydro-Mechanical Deep Drawing Parts

    SciTech Connect

    Shirizly, A.

    2005-08-05

    The increase demand for stronger, lighter and economic sheet metal products, make the Hydromecanical deep drawing process lately more and more popular. The Hydromecanical process is used in almost all types of sheet metal parts from home appliances and kitchenware to automotive and aviation industries. Therefore, many common materials were tested and characterized by their ability to sustain large strains via the well known Forming Limit Diagram (FLD).The aim of this work is to examine the forming capability if the Hydromecanical process in production of hemisphere parts made of materials commonly used in the aviation and aerospace industries. Experimental procedures were carried out to assess their ductility through FLD and the Forming Limit Carve (FLC).Two type of material sheets were tested herewith for demonstrating the procedure: commercial pure titanium and stainless steel 316L. A numerical simulation of the Hydromecanical process was examined and compared to self made Hydromecanical deep drawing of hemispherical parts.

  6. 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.

  7. Structural Performance of Aluminum and Stainless Steel Pyramidal Truss Core Sandwich Panels

    DTIC Science & Technology

    2009-07-01

    condition. The stainless steel core and facesheet components were vacuum brazed after the facesheets were sprayed with braze alloy Nicrobraz* 51 (Ni-25Cr...including brazing and laser spot welding. Typically, austenitic stainless steel (10–11) and age-hardenable aluminum alloys (12) have been used to...periodic cores have been described (3, 4). Initial efforts utilized investment casting of high-fluidity, nonferrous casting alloys (5–9). However

  8. Evaluation of the wear properties of high interstitial stainless steels

    SciTech Connect

    Tylczak, J.H.; Rawers, J.C.; Alman, D.E.

    2007-04-01

    Adding carbon to high nitrogen steels increases interstitial concentrations over what can be obtained with nitrogen addition alone. This can results in an increase in hardness, strength, and wear resistance. The alloys produced for this study were all based on commercially available high-nitrogen Fe-18Cr-18Mn stainless steel. This study is the first significant wear study of these new high interstitial nitrogen-carbon stainless steel alloys. Wear tests included: scratch, pin-on-disk abrasion, dry sand/rubber wheel abrasion, impeller impact, and jet erosion. Increasing interstitial concentration increased strength and hardness and improved wear resistance under all test conditions. The results are discussed in terms of overall interstitial alloy concentration.

  9. METHOD FOR JOINING ALUMINUM TO STAINLESS STEEL

    DOEpatents

    Lemon, L.C.

    1960-05-24

    Aluminum may be joined to stainless steel without the use of flux by tinning the aluminum with a tin solder containing 1% silver and 1% lead, tinning the stainless steel with a 50% lead 50% tin solder, and then sweating the tinned surfaces together.

  10. Localized corrosion of stainless steels in ammonium chloride solutions

    SciTech Connect

    Forsen, O.; Aromaa, J.; Tavi, M.; Virtanen, J.

    1997-05-01

    Ammonium chloride deposition is a well-known problem in oil refining. When these deposits form in a moist environment, they are corrosive to carbon steel. When unexpected corrosion problems are faced, the material is often changed to alloys like stainless steels (SS). Electrochemical measurements were used to study the corrosion resistance of SS in ammonium chloride environments with different chloride contents and at different temperatures.

  11. Manganese-stabilized austenitic stainless steels for fusion applications

    DOEpatents

    Klueh, Ronald L.; Maziasz, Philip J.

    1990-08-07

    An austenitic stainless steel that is comprised of Fe, Cr, Mn, C but no Ni or Nb and minimum N. To enhance strength and fabricability minor alloying additions of Ti, W, V, B and P are made. The resulting alloy is one that can be used in fusion reactor environments because the half-lives of the elements are sufficiently short to allow for handling and disposal.

  12. Manganese-stabilized austenitic stainless steels for fusion applications

    DOEpatents

    Klueh, Ronald L.; Maziasz, Philip J.

    1990-01-01

    An austenitic stainless steel that is comprised of Fe, Cr, Mn, C but no Ni or Nb and minimum N. To enhance strength and fabricability minor alloying additions of Ti, W, V, B and P are made. The resulting alloy is one that can be used in fusion reactor environments because the half-lives of the elements are sufficiently short to allow for handling and disposal.

  13. Resistance of nitrogen-containing stainless alloys to corrosion in chloride media

    SciTech Connect

    Bandy, R.; van Rooyen, D.

    1982-10-08

    The pitting resistance of a series of experimental stainless steels with varying amounts of nickel, chromium, molybdenum, manganese and nitrogen and a number of commercial stainless steels and nickel based alloys has been studied in highly concentrated chloride media. The results show that nitrogen enhancer the pitting resistance of stainless steel and exceptional corrosion resistance is achieved with high levels of nitrogen in combination with suitable amounts of molybdenum and chromium.

  14. Resistance of nitrogen-containing stainless alloys to corrosion in chloride media

    SciTech Connect

    Bandy, R.; van Rooyen, D.

    1982-01-01

    The pitting resistance of a series of experimental stainless steels with varying amounts of nickel, chromium, molybdenum, manganese and nitrogen and a number of commercial stainless steels and nickel based alloys has been studied in highly concentrated chloride media. The results show that nitrogen enhances the pitting resistance of stainless steel and exceptional corrosion resistance is achieved with high levels of nitrogen in combination with suitable amounts of molybdenum and chromium.

  15. Corrosion of stainless steel, 2. edition

    SciTech Connect

    Sedriks, A.J.

    1996-10-01

    The book describes corrosion characteristics in all the major and minor groups of stainless steels, namely, in austenitic, ferritic, martensitic, duplex, and precipitation hardenable steels. Several chapters are spent on those special forms of corrosion that are investigated in the great detail in stainless steels, namely, pitting corrosion, crevice corrosion, and stress corrosion cracking. The influences of thermal treatment (heat affected zone cases), composition, and microstructure on corrosion are given good coverage. Corrosive environments include high temperature oxidation, sulfidation as well as acids, alkalis, various different petroleum plant environments, and even human body fluids (stainless steels are commonly used prosthetic materials).

  16. The use of titanium and stainless steel in fracture fixation.

    PubMed

    Hayes, J S; Richards, R G

    2010-11-01

    The use of metal in fracture fixation has demonstrated unrivalled success for many years owing to its high stiffness, strength, biological toleration and overall reliable function. The most prominent materials used are electropolished stainless steel and commercially pure titanium, along with the more recent emergence of titanium alloys. Despite the many differences between electropolished stainless steel and titanium, both materials provide a relatively predictable clinical outcome, and offer similar success for fulfilling the main biomechanical and biological requirements of fracture fixation despite distinctive differences in implant properties and biological responses. This article explores these differences by highlighting the limitations and advantages of both materials, and addresses how this translates to clinical success.

  17. Bioaccessibility studies of ferro-chromium alloy particles for a simulated inhalation scenario: a comparative study with the pure metals and stainless steel.

    PubMed

    Midander, Klara; de Frutos, Alfredo; Hedberg, Yolanda; Darrie, Grant; Wallinder, Inger Odnevall

    2010-07-01

    research effort was therefore conducted to generate quantitative bioaccessibility data for particles of ferro-chromium alloys compared with particles of the pure metals and stainless steel exposed at in vitro conditions in synthetic biological media of relevance for particle inhalation and ingestion. All results are presented combining bioaccessibility data with aspects of particle characteristics, surface composition, and barrier properties of surface oxides. Iron and chromium were the main elements released from ferro-chromium alloys upon exposure in synthetic biological media. Both elements revealed time-dependent release processes. One week exposures resulted in very small released particle fractions being less than 0.3% of the particle mass at acidic conditions and less than 0.001% in near pH-neutral media. The extent of Fe released from ferro-chromium alloy particles was significantly lower compared with particles of pure Fe, whereas Cr was released to a very low and similar extent as from particles of pure Cr and stainless steel. Low release rates are a result of a surface oxide with passive properties predominantly composed of chromium(III)-rich oxides and silica and, to a lesser extent, of iron(II,III)oxides. Neither the relative bulk alloy composition nor the surface composition can be used to predict or assess the extent of metals released in different synthetic biological media. Ferro-chromium alloys cannot be assessed from the behavior of their pure metal constituents.

  18. Austenitic stainless steel for high temperature applications

    DOEpatents

    Johnson, Gerald D.; Powell, Roger W.

    1985-01-01

    This invention describes a composition for an austenitic stainless steel which has been found to exhibit improved high temperature stress rupture properties. The composition of this alloy is about (in wt. %): 12.5 to 14.5 Cr; 14.5 to 16.5 Ni; 1.5 to 2.5 Mo; 1.5 to 2.5 Mn; 0.1 to 0.4 Ti; 0.02 to 0.08 C; 0.5 to 1.0 Si; 0.01 maximum, N; 0.02 to 0.08 P; 0.002 to 0.008 B; 0.004-0.010 S; 0.02-0.05 Nb; 0.01-0.05 V; 0.005-0.02 Ta; 0.02-0.05 Al; 0.01-0.04 Cu; 0.02-0.05 Co; 0.03 maximum, As; 0.01 maximum, O; 0.01 maximum, Zr; and with the balance of the alloy being essentially iron. The carbon content of the alloy is adjusted such that wt. % Ti/(wt. % C+wt. % N) is between 4 and 6, and most preferably about 5. In addition the sum of the wt. % P+wt. % B+wt. % S is at least 0.03 wt. %. This alloy is believed to be particularly well suited for use as fast breeder reactor fuel element cladding.

  19. Graphene Nanoplatelets Based Protective and Functionalizing Coating for Stainless Steel.

    PubMed

    Mondal, Jayanta; Kozlova, Jekaterina; Sammelselg, Väino

    2015-09-01

    Stainless steel is the most widely used alloy for many industrial and everyday applications, and protection of this alloy substrate against corrosion is an important industrial issue. Here we report a promising application of graphene oxide and graphene nanoplatelets as effective corrosion inhibitors for AISI type 304 stainless steel alloy. The graphene oxide and graphene coatings on the stainless steel substrates were prepared using spin coating techniques. Homogeneous and complete surface coverage by the graphene oxide and graphene nanoplatelets were observed with a high-resolution scanning electron microscope. The corrosion inhibition ability of these materials was investigated through measurement of open circuit potential and followed by potentiodymamic polarization analysis in aqueous sodium chloride solution before and after a month of immersion. Analyzed result exhibits effective corrosion inhibition for both substrates coated with graphene oxide or graphene nanoplatelets by increasing corrosion potential, pitting potential and decreasing passive current density. The corrosion inhibition ability of the coated substrates has not changed even after the long-term immersion. The result showed both graphene materials can be used as an effective corrosion inhibitor for the stainless steel substrates, which would certainly increase lifetime the substrate. However, long-term protection ability of the graphene coated susbtsrate showed somewhat better inhibition performance than the ones coated with graphene oxide.

  20. Crack stability analysis of low alloy steel primary coolant pipe

    SciTech Connect

    Tanaka, T.; Kameyama, M.; Urabe, Y.

    1997-04-01

    At present, cast duplex stainless steel has been used for the primary coolant piping of PWRs in Japan and joints of dissimilar material have been applied for welding to reactor vessels and steam generators. For the primary coolant piping of the next APWR plants, application of low alloy steel that results in designing main loops with the same material is being studied. It means that there is no need to weld low alloy steel with stainless steel and that makes it possible to reduce the welding length. Attenuation of Ultra Sonic Wave Intensity is lower for low alloy steel than for stainless steel and they have advantageous inspection characteristics. In addition to that, the thermal expansion rate is smaller for low alloy steel than for stainless steel. In consideration of the above features of low alloy steel, the overall reliability of primary coolant piping is expected to be improved. Therefore, for the evaluation of crack stability of low alloy steel piping to be applied for primary loops, elastic-plastic future mechanics analysis was performed by means of a three-dimensioned FEM. The evaluation results for the low alloy steel pipings show that cracks will not grow into unstable fractures under maximum design load conditions, even when such a circumferential crack is assumed to be 6 times the size of the wall thickness.

  1. No genotoxicity of a new nickel-free stainless steel.

    PubMed

    Montanaro, L; Cervellati, M; Campoccia, D; Prati, C; Breschi, L; Arciola, C R

    2005-01-01

    Stainless steel is a metallic alloy largely employed in orthopedics, maxillofacial surgery and orthodontic therapy. However, the presence in its composition of a high quantity of nickel, an agent known to trigger toxic, allergic and cancerogenous responses in humans, is cause of some concern. In this study, we have investigated the in vitro mutagenicity and genotoxicity of a new nickel-free stainless steel, namely P558, in comparison to the conventional stainless steel AISI 316L. The cytogenetic effects were evaluated by studying the frequency of Sister Chromatid Exchanges (SCE) and chromosomal aberrations. Ames test was performed to detect the mutagenic activity. Both P558 and AISI 316L did not cause any significant increase in the average number of SCE and in chromosomal aberrations, either with or without metabolic activation. Furthermore, the Ames test showed that the extracts of both P558 and of AISI 316L are not mutagenic. Overall, these findings prove that P558 is devoid of genotoxicity and mutagenicity. The present results, together with other previous interesting observations that P558 promotes osseointegration, suggest that this new nickel-free stainless steel can represent a better alternative to other conventional steel alloys.

  2. Bactericidal behavior of Cu-containing stainless steel surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangyu; Huang, Xiaobo; Ma, Yong; Lin, Naiming; Fan, Ailan; Tang, Bin

    2012-10-01

    Stainless steels are one of the most common materials used in health care environments. However, the lack of antibacterial advantage has limited their use in practical application. In this paper, antibacterial stainless steel surfaces with different Cu contents have been prepared by plasma surface alloying technology (PSAT). The steel surface with Cu content 90 wt.% (Cu-SS) exhibits strong bactericidal activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) within 3 h. Although the Cu-containing surface with Cu content 2.5 wt.% (CuNi-SS) can also kill all tested bacteria, this process needs 12 h. SEM observation of the bacterial morphology and an agarose gel electrophoresis were performed to study the antibacterial mechanism of Cu-containing stainless steel surfaces against E. coli. The results indicated that Cu ions are released when the Cu-containing surfaces are in contact with bacterial and disrupt the cell membranes, killing the bacteria. The toxicity of Cu-alloyed surfaces does not cause damage to the bacterial DNA. These results provide a scientific explanation for the antimicrobial applications of Cu-containing stainless steel. The surfaces with different antibacterial abilities could be used as hygienic surfaces in healthcare-associated settings according to the diverse requirement of bactericidal activities.

  3. Phase Transformations in Cast Duplex Stainless Steels

    SciTech Connect

    Kim, Yoon-Jun

    2004-01-01

    Duplex stainless steels (DSS) constitute both ferrite and austenite as a matrix. Such a microstructure confers a high corrosion resistance with favorable mechanical properties. However, intermetallic phases such as σ and χ can also form during casting or high-temperature processing and can degrade the properties of the DSS. This research was initiated to develop time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams of two types of cast duplex stainless steels, CD3MN (Fe-22Cr-5Ni-Mo-N) and CD3MWCuN (Fe-25Cr-7Ni-Mo-W-Cu-N), in order to understand the time and temperature ranges for intermetallic phase formation. The alloys were heat treated isothermally or under controlled cooling conditions and then characterized using conventional metallographic methods that included tint etching, and also using electron microscopy (SEM, TEM) and wavelength dispersive spectroscopy (WDS). The kinetics of intermetallic-phase (σ + χ) formation were analyzed using the Johnson-Mehl-Avrami (MA) equation in the case of isothermal transformations and a modified form of this equation in the case of continuous cooling transformations. The rate of intermetallic-phase formation was found to be much faster in CD3MWCuN than CD3MN due mainly to differences in the major alloying contents such as Cr, Ni and Mo. To examine in more detail the effects of these elements of the phase stabilities; a series of eight steel castings was designed with the Cr, Ni and Mo contents systematically varied with respect to the nominal composition of CD3MN. The effects of varying the contents of alloying additions on the formation of intermetallic phases were also studied computationally using the commercial thermodynamic software package, Thermo-Calc. In general, σ was stabilized with increasing Cr addition and χ by increasing Mo addition. However, a delicate balance among Ni and other minor elements such as N and Si also exists. Phase equilibria in DSS can be affected by

  4. Flow Behavior Modeling of a Nitrogen-Alloyed Ultralow Carbon Stainless Steel During Hot Deformation: A Comparative Study of Constitutive Models

    NASA Astrophysics Data System (ADS)

    Shang, Xuekun; He, An; Wang, Yanli; Yang, Xiaoya; Zhang, Hailong; Wang, Xitao

    2015-10-01

    The present study focuses on comparison of accuracy of Johnson-Cook, modified Johnson-Cook, and modified Zerilli-Armstrong constitutive models to predict flow behavior of a nitrogen-alloyed ultralow carbon stainless steel at evaluated temperature. True strain-true stress data obtained from hot compression experiments performed with temperatures of 1223-1423 K and strain rates of 0.001-10 s-1 on a Gleeble-3500 thermal-simulator were employed to develop these three models. Furthermore, the ability of the three models to predict the outcomes was evaluated by comparing the correlation coefficient, absolute average related error, ability to track the experimental flow stress, numbers of material constants, and computational time required to develop models. The results show that the modified Johnson-Cook has a better description of the flow behaviors of the studied steel than the other two models. However, under certain conditions, the modified Zerilli-Armstrong model has accuracy comparable to the modified Johnson-Cook model.

  5. In vitro corrosion study by EIS of an equiatomic NiTi alloy and an implant quality AISI 316 stainless steel.

    PubMed

    Rondelli, G; Torricelli, P; Fini, M; Rimondini, L; Giardino, R

    2006-11-01

    The electrochemical impedance spectroscopy (EIS) technique was used for the study of the electrochemical behavior of an equiatomic NiTi alloy and an implant quality AISI 316 stainless steel type ASTM F138. Experiments were carried out using four different different test solutions: phosphate buffered saline (PBS), Dulbecco minimum essential medium (MEM), MEM + fetal calf serum (FCS), and MEM + fetal calf serum + fibroblast cell (CELL). Specimens were finished to 600-grit SiC paper and were tested in conditions that did not provoke abrupt mechanical damage of the passive film. Bode-phase spectra showed the presence of two maxima and were fitted with an equivalent circuit characterized by two parallel combinations (R, resistance; CPE, constant phase element). The R(1) and CPE(1) branch was assigned to the inner compact passive film and the R(2) and CPE(2) branch to the external porous film. The resistance of the inner film R(1), roughly corresponding to the polarization resistance (R(p)), which is inversely proportional to the material's corrosion rate, increased with the immersion time and was generally greater in PBS than in other media. With the exception of FCS solution, R(1) for NiTi alloy is better or similar to that of ASTM F138.

  6. Tritiated Water Interaction with Stainless Steel

    SciTech Connect

    Glen R. Longhurst

    2007-05-01

    Experiments conducted to study tritium permeation of stainless steel at ambient and elevated temperatures revealed that HT converts relatively quickly to HTO. Further, the HTO partial pressure contributes essentially equally with elemental tritium gas in driving permeation through the stainless steel. Such permeation appears to be due to dissociation of the water molecule on the hot stainless steel surface. There is an equilibrium concentration of HTO vapor above adsorbed gas on the walls of the experimental apparatus evident from freezing transients. The uptake process of tritium from the carrier gas involves both surface adsorption and isotopic exchange with surface bound water.

  7. Pitting and crevice corrosion of stainless steels in ammonium chloride solutions

    SciTech Connect

    Forsen, O.; Aromaa, J.; Virtanen, J.; Tavi, M.

    1995-09-01

    Carbon steel is the most commonly used construction material in oil refining. Ammonium chloride deposition is a well known problem in oil refining. When these deposits form in a moist environment, they are corrosive to carbon steel. When unexpected corrosion problems are faced the material is often changed zn to alloys like stainless steels. The main drawback of stainless steels is that they are prone to different forms of localized corrosion, especially in the presence of halides. In this paper the use of electrochemical measurements to study the corrosion resistance of stainless steels is discussed.

  8. Alumina-Forming Austenitics: A New Class of Heat-Resistant Stainless Steels

    SciTech Connect

    Brady, Michael P; Yamamoto, Yukinori; Lu, Zhao Ping; Maziasz, Philip J; Liu, Chain T; Pint, Bruce A; Santella, Michael L

    2008-01-01

    A family of alumina (Al2O3)-forming austenitic (AFA) stainless steels is under development. These alloys offer the potential for significantly higher operating temperature and environmental durability than conventional chromia (Cr2O3)-forming stainless steels, without sacrificing other critical characteristics such as cost, creep resistance, and weldability. An overview of the alloy development approach and details of the oxidation and creep resistance properties achieved to date are presented.

  9. A review on nickel-free nitrogen containing austenitic stainless steels for biomedical applications.

    PubMed

    Talha, Mohd; Behera, C K; Sinha, O P

    2013-10-01

    The field of biomaterials has become a vital area, as these materials can enhance the quality and longevity of human life. Metallic materials are often used as biomaterials to replace structural components of the human body. Stainless steels, cobalt-chromium alloys, commercially pure titanium and its alloys are typical metallic biomaterials that are being used for implant devices. Stainless steels have been widely used as biomaterials because of their very low cost as compared to other metallic materials, good mechanical and corrosion resistant properties and adequate biocompatibility. However, the adverse effects of nickel ions being released into the human body have promoted the development of "nickel-free nitrogen containing 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 and emphatically the advantages of nitrogen in stainless steel, as well as the development of nickel-free nitrogen containing stainless steels for medical applications. By combining the benefits of stable austenitic structure, high strength, better corrosion and wear resistance and superior biocompatibility in comparison to the currently used austenitic stainless steel (e.g. 316L), the newly developed nickel-free high nitrogen austenitic stainless steel is a reliable substitute for the conventionally used medical stainless steels.

  10. Nanoparticle Treated Stainless Steel Filters for Metal Vapor Sequestration

    NASA Astrophysics Data System (ADS)

    Murph, Simona E. Hunyadi; Larsen, George K.; Korinko, Paul; Coopersmith, Kaitlin J.; Summer, Ansley J.; Lewis, Rebecca

    2016-12-01

    The ability to sequester vapor phase radioactive compounds during industrial processes reduces the exposure of workers and the environment to dangerous radioactive materials. Nanomaterials have a lot of potential in this area because they typically demonstrate size- and shape-dependent properties with higher reactivity than bulk. This is due to the increased surface area-to-volume ratio and quantum size effects. In this report, we developed a gold nanomaterial-treated stainless steel filter, namely wools and coupons, that can be efficiently used for zinc vapor sequestration. Without nanoparticle modification, stainless steel coupons do not react or alloy with Zn. Gold nanomaterials were grown onto various stainless steel filters using solution chemistry that is amenable to scaling up. Materials were characterized by electron microscopy, inductively coupled plasma mass spectroscopy and dynamic light scattering before and after exposure to zinc vapors. X-ray diffraction, high-resolution transmission electron microscopy, energy dispersive x-ray spectroscopy mapping and ultraviolet-visible spectroscopy confirm the formation of gold-zinc alloys after Zn vapor exposure. The effect of surface topography on nanoparticle morphology, size and loading density were also investigated, and stainless steel surface defects were found to have an impact on the Au NP growth and subsequently Zn sequestration.

  11. Nanoparticle Treated Stainless Steel Filters for Metal Vapor Sequestration

    NASA Astrophysics Data System (ADS)

    Murph, Simona E. Hunyadi; Larsen, George K.; Korinko, Paul; Coopersmith, Kaitlin J.; Summer, Ansley J.; Lewis, Rebecca

    2017-02-01

    The ability to sequester vapor phase radioactive compounds during industrial processes reduces the exposure of workers and the environment to dangerous radioactive materials. Nanomaterials have a lot of potential in this area because they typically demonstrate size- and shape-dependent properties with higher reactivity than bulk. This is due to the increased surface area-to-volume ratio and quantum size effects. In this report, we developed a gold nanomaterial-treated stainless steel filter, namely wools and coupons, that can be efficiently used for zinc vapor sequestration. Without nanoparticle modification, stainless steel coupons do not react or alloy with Zn. Gold nanomaterials were grown onto various stainless steel filters using solution chemistry that is amenable to scaling up. Materials were characterized by electron microscopy, inductively coupled plasma mass spectroscopy and dynamic light scattering before and after exposure to zinc vapors. X-ray diffraction, high-resolution transmission electron microscopy, energy dispersive x-ray spectroscopy mapping and ultraviolet-visible spectroscopy confirm the formation of gold-zinc alloys after Zn vapor exposure. The effect of surface topography on nanoparticle morphology, size and loading density were also investigated, and stainless steel surface defects were found to have an impact on the Au NP growth and subsequently Zn sequestration.

  12. Metal release from stainless steel in biological environments: A review.

    PubMed

    Hedberg, Yolanda S; Odnevall Wallinder, Inger

    2015-03-29

    Due to its beneficial corrosion resistance, stainless steel is widely used in, e.g., biomedical applications, as surfaces in food contact, and for products intended to come into skin contact. Low levels of metals can be released from the stainless steel surface into solution, even for these highly corrosion resistant alloys. This needs to be considered in risk assessment and management. This review aims to compile the different metal release mechanisms that are relevant for stainless steel when used in different biological settings. These mechanisms include corrosion-induced metal release, dissolution of the surface oxide, friction-induced metal release, and their combinations. The influence of important physicochemical surface properties, different organic species and proteins in solution, and of biofilm formation on corrosion-induced metal release is discussed. Chemical and electrochemical dissolution mechanisms of the surface oxides of stainless steel are presented with a focus on protonation, complexation/ligand-induced dissolution, and reductive dissolution by applying a perspective on surface adsorption of complexing or reducing ligands and proteins. The influence of alloy composition, microstructure, route of manufacture, and surface finish on the metal release process is furthermore discussed as well as the chemical speciation of released metals. Typical metal release patterns are summarized.

  13. Precise carbon control of fabricated stainless steel

    DOEpatents

    Nilsen, R.J.

    1975-12-01

    A process is described for controlling the carbon content of fabricated stainless steel components including the steps of heat treating the component in hydrogen atmospheres of varying dewpoints and carbon potentials.

  14. Stainless Steel to Titanium Bimetallic Transitions

    SciTech Connect

    Kaluzny, J. A.; Grimm, C.; Passarelli, D.

    2015-01-01

    In order to use stainless steel piping in an LCLS-II (Linac Coherent Light Source Upgrade) cryomodule, stainless steel to titanium bimetallic transitions are needed to connect the stainless steel piping to the titanium cavity helium vessel. Explosion bonded stainless steel to titanium transition pieces and bimetallic transition material samples have been tested. A sample transition tube was subjected to tests and x-ray examinations between tests. Samples of the bonded joint material were impact and tensile tested at room temperature as well as liquid helium temperature. The joint has been used successfully in horizontal tests of LCLS-II cavity helium vessels and is planned to be used in LCLS-II cryomodules. Results of material sample and transition tube tests will be presented.

  15. Hydrogen compatibility handbook for stainless steels

    SciTech Connect

    Caskey, G.R. Jr.

    1983-06-01

    This handbook compiles data on the effects of hydrogen on the mechanical properties of stainless steels and discusses this data within the context of current understanding of hydrogen compatibility of metals. All of the tabulated data derives from continuing studies of hydrogen effects on materials that have been conducted at the Savannah River Laboratory over the past fifteen years. Supplementary data from other sources are included in the discussion. Austenitic, ferritic, martensitic, and precipitation hardenable stainless steels have been studied. Damage caused by helium generated from decay of tritium is a distinctive effect that occurs in addition to the hydrogen isotopes protium and deuterium. The handbook defines the scope of our current knowledge of hydrogen effects in stainless steels and serves as a guide to selection of stainless steels for service in hydrogen.

  16. Use of duplex stainless steel castings in control valves

    SciTech Connect

    Gossett, J.L.

    1996-07-01

    Duplex stainless steels have enjoyed rapidly increasing popularity in recent years. For numerous reasons the availability of these alloys in the cast form has lagged behind the availability of the wrought form. Commercial demand for control valves in these alloys has driven development of needed information to move into production. A systematic approach was used to develop specifications, suppliers and weld procedures. Corrosion, stress corrosion cracking (SCC), sulfide stress cracking (SSC) and hardness results are also presented for several alloys including; CD3MN (UNS J92205), CD4MCu (UNS J93370) and CD7MCuN (cast UNS S32550).

  17. Mechanical Properties of Austenitic Stainless Steel Made by Additive Manufacturing

    PubMed Central

    Luecke, William E; Slotwinski, John A

    2014-01-01

    Using uniaxial tensile and hardness testing, we evaluated the variability and anisotropy of the mechanical properties of an austenitic stainless steel, UNS S17400, manufactured by an additive process, selective laser melting. Like wrought materials, the mechanical properties depend on the orientation introduced by the processing. The recommended stress-relief heat treatment increases the tensile strength, reduces the yield strength, and decreases the extent of the discontinuous yielding. The mechanical properties, assessed by hardness, are very uniform across the build plate, but the stress-relief heat treatment introduced a small non-uniformity that had no correlation to position on the build plate. Analysis of the mechanical property behavior resulted in four conclusions. (1) The within-build and build-to-build tensile properties of the UNS S17400 stainless steel are less repeatable than mature engineering structural alloys, but similar to other structural alloys made by additive manufacturing. (2) The anisotropy of the mechanical properties of the UNS S17400 material of this study is larger than that of mature structural alloys, but is similar to other structural alloys made by additive manufacturing. (3) The tensile mechanical properties of the UNS S17400 material fabricated by selective laser melting are very different from those of wrought, heat-treated 17-4PH stainless steel. (4) The large discontinuous yielding strain in all tests resulted from the formation and propagation of Lüders bands. PMID:26601037

  18. Mechanical Properties of Austenitic Stainless Steel Made by Additive Manufacturing.

    PubMed

    Luecke, William E; Slotwinski, John A

    2014-01-01

    Using uniaxial tensile and hardness testing, we evaluated the variability and anisotropy of the mechanical properties of an austenitic stainless steel, UNS S17400, manufactured by an additive process, selective laser melting. Like wrought materials, the mechanical properties depend on the orientation introduced by the processing. The recommended stress-relief heat treatment increases the tensile strength, reduces the yield strength, and decreases the extent of the discontinuous yielding. The mechanical properties, assessed by hardness, are very uniform across the build plate, but the stress-relief heat treatment introduced a small non-uniformity that had no correlation to position on the build plate. Analysis of the mechanical property behavior resulted in four conclusions. (1) The within-build and build-to-build tensile properties of the UNS S17400 stainless steel are less repeatable than mature engineering structural alloys, but similar to other structural alloys made by additive manufacturing. (2) The anisotropy of the mechanical properties of the UNS S17400 material of this study is larger than that of mature structural alloys, but is similar to other structural alloys made by additive manufacturing. (3) The tensile mechanical properties of the UNS S17400 material fabricated by selective laser melting are very different from those of wrought, heat-treated 17-4PH stainless steel. (4) The large discontinuous yielding strain in all tests resulted from the formation and propagation of Lüders bands.

  19. 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.

  20. Stainless Steels’ Resistance to Hydroerosion,

    DTIC Science & Technology

    1980-07-30

    Omel’chenko, engineer, S. L. Millichenko, A. G. Aleksandrov, Candidates of Technical Sciences Thanks to a high corrosion resistance stainless steels have...has great significance. The resistance to hydroerosion of several of the most common types of stainless steels which have roughly the same corrosion ...the failure is first localized in the ferrite phase and occurs by means of plastic deformation and the development of fatigue micro- cracks both

  1. Corrosion characteristics of ferric and austenitic stainless steels for dental magnetic attachment.

    PubMed

    Endo, K; Suzuki, M; Ohno, H

    2000-03-01

    The corrosion behaviors of four ferric stainless steels and two austenitic stainless steels were examined in a simulated physiological environment (0.9% NaCl solution) to obtain basic data for evaluating the appropriate composition of stainless steels for dental magnetic attachments. The corrosion resistance was evaluated by electrochemical techniques and the analysis of released metal ions by atomic absorption spectrophotometry. The surface of the stainless steels was analyzed by X-ray photoelectron spectroscopy (XPS). The breakdown potential of ferric stainless steels increased and the total amount of released metal ions decreased linearly with increases in the sum of the Cr and Mo contents. The corrosion rate of the ferric stainless steels increased 2 to 6 times when they were galvanically coupled with noble metal alloys but decreased when coupled with commercially pure Ti. For austenitic stainless steels, the breakdown potential of high N-bearing stainless steel was approximately 500 mV higher than that of SUS316L, which is currently used as a component in dental magnetic attachments. The enriched nitrogen at the alloy/passive film interface may be effective in improving the localized corrosion resistance.

  2. Low Cycle Fatigue Behavior of 316LN Stainless Steel Alloyed with Varying Nitrogen Content. Part II: Fatigue Life and Fracture Behavior

    NASA Astrophysics Data System (ADS)

    Prasad Reddy, G. V.; Sandhya, R.; Sankaran, S.; Mathew, M. D.

    2014-10-01

    Influence of nitrogen content on low cycle fatigue life and fracture behavior of 316LN stainless steel (SS) alloyed with 0.07 to 0.22 wt pct nitrogen is presented in this paper over a range of total strain amplitudes ( ±0.25 to 1.0 pct) in the temperature range from 773 K to 873 K (500 °C to 600 °C). The combined effect of nitrogen and strain amplitude on fatigue life is observed to be complex i.e., fatigue life either decreases/increases with increase in nitrogen content or saturates/peaks at 0.14 wt pct N depending on strain amplitude and temperature. Coffin-Manson plots (CMPs) revealed both single-slope and dual-slope strain-life curves depending on the test temperature and nitrogen content. 316LN SS containing 0.07 and 0.22 wt pct N showed nearly single-slope CMP at all test temperatures, while 316LN SS with 0.11 and 0.14 wt pct N exhibited marked dual-slope behavior at 773 K (500 °C) that changes to single-slope behavior at 873 K (600 °C). The changes in slope of CMP are found to be in good correlation with deformation substructural changes.

  3. HIGH TEMPERATURE BRAZING ALLOY FOR JOINT Fe-Cr-Al MATERIALS AND AUSTENITIC AND FERRITIC STAINLESS STEELS

    DOEpatents

    Cost, R.C.

    1958-07-15

    A new high temperature brazing alloy is described that is particularly suitable for brazing iron-chromiumaluminum alloys. It consists of approximately 20% Cr, 6% Al, 10% Si, and from 1.5 to 5% phosphorus, the balance being iron.

  4. Development of Advanced Corrosion-Resistant Fe-Cr-Ni Austenitic Stainless Steel Alloy with Improved High-Temperature Strength and Creep-Resistance

    SciTech Connect

    Maziasz, P.J.; Swindeman, R.W.

    2001-06-15

    In February of 1999, a Cooperative Research and Development Agreement (CRADA) was undertaken between Oak Ridge National Laboratory (ORNL) and Special Metals Corporation - Huntington Alloys (formerly INCO Alloys International, Inc.) to develop a modified wrought austenitic stainless alloy with considerably more strength and corrosion resistance than alloy 800H or 800HT, but with otherwise similar engineering and application characteristics. Alloy 800H and related alloys have extensive use in coal flue gas environments, as well as for tubing or structural components in chemical and petrochemical applications. The main concept of the project was make small, deliberate elemental microalloying additions to this Fe-based alloy to produce, with proper processing, fine stable carbide dispersions for enhanced high temperature creep-strength and rupture resistance, with similar or better oxidation/corrosion resistance. The project began with alloy 803, a Fe-25Cr-35NiTi,Nb alloy recently developed by INCO, as the base alloy for modification. Smaller commercial developmental alloy heats were produced by Special Metal. At the end of the project, three rounds of alloy development had produced a modified 803 alloy with significantly better creep resistance above 815 C (1500 C) than standard alloy 803 in the solution-annealed (SA) condition. The new upgraded 803 alloy also had the potential for a processing boost in that creep resistance for certain kinds of manufactured components that was not found in the standard alloy. The upgraded 803 alloy showed similar or slightly better oxidation and corrosion resistance relative to standard 803. Creep strength and oxidation/corrosion resistance of the upgraded 803 alloy were significantly better than found in alloy 800 H, as originally intended. The CRADA was terminated in February 2003. A contributing factor was Special Metals Corporation being in Chapter 11 Bankruptcy. Additional testing, further commercial scale-up, and any potential

  5. Forming "dynamic" membranes on stainless steel

    NASA Technical Reports Server (NTRS)

    Brandon, C. A.; Gaddis, J. L.

    1979-01-01

    "Dynamic" zirconium polyacrylic membrane is formed directly on stainless steel substrate without excessive corrosion of steel. Membrane is potentially useful in removal of contaminated chemicals from solution through reversed osmosis. Application includes use in filtration and desalination equipment, and in textile industry for separation of dyes from aqueous solvents.

  6. Ion-nitriding of austenitic stainless steels

    SciTech Connect

    Pacheco, O.; Hertz, D.; Lebrun, J.P.; Michel, H.

    1995-12-31

    Although ion-nitriding is an extensively industrialized process enabling steel surfaces to be hardened by nitrogen diffusion, with a resulting increase in wear, seizure and fatigue resistance, its direct application to stainless steels, while enhancing their mechanical properties, also causes a marked degradation in their oxidation resistance. However, by adaption of the nitriding process, it is possible to maintain the improved wear resistant properties while retaining the oxidation resistance of the stainless steel. The controlled diffusion permits the growth of a nitrogen supersaturated austenite layer on parts made of stainless steel (AISI 304L and 316L) without chromium nitride precipitation. The diffusion layer remains stable during post heat treatments up to 650 F for 5,000 hrs and maintains a hardness of 900 HV. A very low and stable friction coefficient is achieved which provides good wear resistance against stainless steels under diverse conditions. Electrochemical and chemical tests in various media confirm the preservation of the stainless steel characteristics. An example of the application of this process is the treatment of Reactor Control Rod Cluster Assemblies (RCCAs) for Pressurized Water Nuclear Reactors.

  7. Hot Corrosion Behavior of Stainless Steel with Al-Si/Al-Si-Cr Coating

    NASA Astrophysics Data System (ADS)

    Fu, Guangyan; Wu, Yongzhao; Liu, Qun; Li, Rongguang; Su, Yong

    2017-03-01

    The 1Cr18Ni9Ti stainless steel with Al-Si/Al-Si-Cr coatings is prepared by slurry process and vacuum diffusion, and the hot corrosion behavior of the stainless steel with/without the coatings is studied under the condition of Na2SO4 film at 950 °C in air. Results show that the corrosion kinetics of stainless steel, the stainless steel with Al-Si coating and the stainless steel with Al-Si-Cr coating follow parabolic laws in several segments. After 24 h corrosion, the sequence of the mass gain for the three alloys is the stainless steel with Al-Si-Cr coating < the stainless steel with Al-Si coating < the stainless steel without any coating. The corrosion products of the three alloys are layered. Thereinto, the corrosion products of stainless steel without coating are divided into two layers, where the outside layer contains a composite of Fe2O3 and FeO, and the inner layer is Cr2O3. The corrosion products of the stainless steel with Al-Si coating are also divided into two layers, of which the outside layer mainly consists of Cr2O3, and the inner layer is mainly SiO2. The corrosion film of the stainless steel with Al-Si-Cr coating is thin and dense, which combines well with substrate. Thereinto, the outside layer is mainly Cr2O3, and the inside layer is Al2O3. In the matrix of all of the three alloys, there exist small amount of sulfides. Continuous and protective films of Cr2O3, SiO2 and Al2O3 form on the surface of the stainless steel with Al-Si and Al-Si-Cr coatings, which prevent further oxidation or sulfide corrosion of matrix metals, and this is the main reason for the much smaller mass gain of the two alloys than that of the stainless steel without any coatings in the 24 h hot corrosion process.

  8. Development of Cast Alumina-Forming Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Muralidharan, G.; Yamamoto, Y.; Brady, M. P.; Walker, L. R.; Meyer, H. M., III; Leonard, D. N.

    2016-11-01

    Cast Fe-Ni-Cr chromia-forming austenitic stainless steels with Ni levels up to 45 wt.% are used at high temperatures in a wide range of industrial applications that demand microstructural stability, corrosion resistance, and creep strength. Although alumina scales offer better corrosion protection at these temperatures, designing cast austenitic alloys that form a stable alumina scale and achieve creep strength comparable to existing cast chromia-forming alloys is challenging. This work outlines the development of cast Fe-Ni-Cr-Al austenitic stainless steels containing about 25 wt.% Ni with good creep strength and the ability to form a protective alumina scale for use at temperatures up to 800-850°C in H2O-, S-, and C-containing environments. Creep properties of the best alloy were comparable to that of HK-type cast chromia-forming alloys along with improved oxidation resistance typical of alumina-forming alloys. Challenges in the design of cast alloys and a potential path to increasing the temperature capability are discussed.

  9. Accelerated corrosion of stainless steel in thiocyanate-containing solutions

    SciTech Connect

    Pistorius, P Chris; Li, Wen

    2012-09-19

    It is known that reduced sulfur compounds (such as thiocyanate and thiosulfate) can accelerate active corrosion of austenitic stainless steel in acid solutions, but before we started this project the mechanism of acceleration was largely unclear. This work combined electrochemical measurements and analysis using scanning electron microscopy (SEM) and X-ray photo-electron spectroscopy (XPS), which provided a comprehensive understanding of the catalytic effect of reduced sulfur species on the active corrosion of stainless steel. Both the behavior of the pure elements and the steel were studied and the work focused on the interaction between the pure elements of the steel, which is the least understood area. Upon completion of this work, several aspects are now much clearer. The main results from this work can be summarized as follows: The presence of low concentrations (around 0.1 mM) of thiocyanate or tetrathionate in dilute sulfuric acid greatly accelerates the anodic dissolution of chromium and nickel, but has an even stronger effect on stainless steels (iron-chromium-nickel alloys). Electrochemical measurements and surface analyses are in agreement with the suggestion that accelerated dissolution really results from suppressed passivation. Even well below the passivation potential, the electrochemical signature of passivation is evident in the electrode impedance; the electrode impedance shows clearly that this pre-passivation is suppressed in the presence of thiocyanate. For the stainless steels, remarkable changes in the morphology of the corroded metal surface and in the surface concentration of chromium support the suggestion that pre-passivation of stainless steels is suppressed because dissolution of chromium is accelerated. Surface analysis confirmed that adsorbed sulfur / sulfide forms on the metal surfaces upon exposure to solutions containing thiocyanate or thiosulfate. For pure nickel, and steels containing nickel (and residual copper), bulk sulfide

  10. Aging degradation of cast stainless steel

    SciTech Connect

    Chopra, O.K.; Chung, H.M.

    1985-10-01

    A program is being conducted to investigate the significance of in-service embrittlement of cast-duplex stainless steels under light-water reactor operating conditions. Data from room-temperature Charpy-impact tests for several heats of cast stainless steel aged up to 10,000 h at 350, 400, and 450/sup 0/C are presented and compared with results from other studies. Microstructures of cast-duplex stainless steels subjected to long-term aging either in the laboratory or in reactor service have been characterized. The results indicate that at least two processes contribute to the low-temperature embrittleent of duplex stainless steels, viz., weakening of the ferrite/austenite phase boundary by carbide precipitation and embrittlement of ferrite matrix by the formation of additional phases such as G-phase, Type X, or the ..cap alpha..' phase. Carbide precipitation has a significant effect on the onset of embrittlement of CF-8 and -8M grades of stainless steels aged at 400 or 450/sup 0/C. The existing correlations do not accurately represent the embrittlement behavior over the temperature range 300 to 450/sup 0/C. 18 refs., 13 figs.

  11. Long-term corrosion evaluation of stainless steels in Space Shuttle iodinated resin and water

    NASA Technical Reports Server (NTRS)

    Krohn, Douglas D.

    1992-01-01

    The effects of stainless steel exposure to iodinated water is a concern in developing the Integrated Water System (IWS) for Space Station Freedom. The IWS has a life requirement of 30 years, but the effects of general and localized corrosion over such a long period have not been determined for the candidate materials. In 1978, Umpqua Research Center immersed stainless steel 316L, 321, and 347 specimens in a solution of deionized water and the Space Shuttle microbial check valve resin. In April 1990, the solution was chemically analyzed to determine the level of corrosion formed, and the surface of each specimen was examined with scanning electron microscopy and metallography to determine the extent of general and pitting corrosion. This examination showed that the attack on the stainless steels was negligible and never penetrated past the first grain boundary layer. Of the three alloys, 316L performed the best; however, all three materials proved to be compatible with an aqueous iodine environment. In addition to the specimens exposed to aqueous iodine, a stainless steel specimen (unspecified alloy) was exposed to moist microbial check valve resin and air for a comparable period. This environment allowed contact of the metal to the resin as well as to the iodine vapor. Since the particular stainless steel alloy was not known, energy dispersive spectroscopy was used to determine that this alloy was stainless steel 301. The intergranular corrosion found on the specimen was limited to the first grain boundary layer.

  12. Shrinkage Prediction for the Investment Casting of Stainless Steels

    SciTech Connect

    Sabau, Adrian S

    2007-01-01

    In this study, the alloy shrinkage factors were obtained for the investment casting of 17-4PH stainless steel parts. For the investment casting process, unfilled wax and fused silica with a zircon prime coat were used for patterns and shell molds, respectively. Dimensions of the die tooling, wax pattern, and casting were measured using a Coordinate Measurement Machine in order to obtain the actual tooling allowances. The alloy dimensions were obtained from numerical simulation results of solidification, heat transfer, and deformation phenomena. The numerical simulation results for the shrinkage factors were compared with experimental results.

  13. Superplastic Forming of Duplex Stainless Steel for Aerospace Part

    NASA Astrophysics Data System (ADS)

    Lee, Ho-Sung; Yoon, Jong-Hoon; Yoo, Joon-Tae; Yi, Young-Moo

    2011-08-01

    In this study, the high temperature forming behavior of duplex stainless steel has been characterized and the outer shell of a combustion chamber was fabricated with pressure difference of hot gas. It consists of two parts which are the outer skin made of stainless steel to sustain the internal pressure and the inner shell made of copper alloy for regenerative cooling channels. Two outer skins partitioned to half with respect to the symmetric axis was prepared by hot gas forming process with a maximum pressure of 7 MPa following to FEM analysis. For inner layer, copper alloy was machined for cooling channels and then placed in the gas pressure welding fixture. It is shown that the optimum condition of gas pressure welding is 7 MPa at 890 °C, for one hour. EDX analysis and scanning electron microscope micrograph confirm the atomic diffusion process is observed at the interface and copper atoms diffuse into steel, while iron and chrome atoms diffuse into copper. The result shows that the manufacturing method with superplastic forming and gas pressure welding of steel and copper alloy has been successful for near net shape manufacturing of scaled combustion chamber of launch vehicle.

  14. Superplastic Forming of Duplex Stainless Steel for Aerospace Part

    SciTech Connect

    Lee, Ho-Sung; Yoon, Jong-Hoon; Yoo, Joon-Tae; Yi, Young-Moo

    2011-08-22

    In this study, the high temperature forming behavior of duplex stainless steel has been characterized and the outer shell of a combustion chamber was fabricated with pressure difference of hot gas. It consists of two parts which are the outer skin made of stainless steel to sustain the internal pressure and the inner shell made of copper alloy for regenerative cooling channels. Two outer skins partitioned to half with respect to the symmetric axis was prepared by hot gas forming process with a maximum pressure of 7 MPa following to FEM analysis. For inner layer, copper alloy was machined for cooling channels and then placed in the gas pressure welding fixture. It is shown that the optimum condition of gas pressure welding is 7 MPa at 890 deg. C, for one hour. EDX analysis and scanning electron microscope micrograph confirm the atomic diffusion process is observed at the interface and copper atoms diffuse into steel, while iron and chrome atoms diffuse into copper. The result shows that the manufacturing method with superplastic forming and gas pressure welding of steel and copper alloy has been successful for near net shape manufacturing of scaled combustion chamber of launch vehicle.

  15. Kohonen mapping of the crack growth under fatigue loading conditions of stainless steels in BWR environments and of nickel alloys in PWR environments

    NASA Astrophysics Data System (ADS)

    Urquidi-Macdonald, Mirna

    2008-09-01

    In this study, crack growth rate data under fatigue loading conditions generated by Argonne National Laboratories and published in 2006 were analyzed [O.K. Chopra, B. Alexandreanu, E.E. Gruber, R.S. Daum, W.J. Shack, Argonne National Laboratory, NUREG CR 6891-series ANL 04/20, Crack Growth Rates of Austenitic Stainless Steel Weld Heat Affected Zone in BWR Environments, January, 2006; B. Alexandreanu, O.K. Chopra, H.M. Chung, E.E. Gruber, W.K. Soppet, R.W. Strain, W.J. Shack, Environmentally Assisted Cracking in Light Water Reactors, vol. 34 in the NUREG/CR-4667 series annual report of Argonne National Laboratory program studies for Calendar (Annual Report 2003). Manuscript Completed: May 2005, Date Published: May 2006], and reported by DoE [B. Alexandreanu, O.K. Chopra, W.J. Shack, S. Crane, H.J. Gonzalez, NRC, Crack Growth Rates and Metallographic Examinations of Alloy 600 and Alloy 82/182 from Field Components and Laboratory Materials Tested in PWR Environments, NUREG/CR-6964, May 2008]. The data collected were measured on austenitic stainless steels in BWR (boiling water reactor) environments and on nickel alloys in PWR (pressurized water reactor) environments. The data collected contained information on material composition, temperature, conductivity of the environment, oxygen concentration, irradiated sample information, weld information, electrochemical potential, load ratio, rise time, hydrogen concentration, hold time, down time, maximum stress intensity factor ( Kmax), stress intensity range (Δ Kmax), crack length, and crack growth rates (CGR). Each position on that Kohonen map is called a cell. A Kohonen map clusters vectors of information by 'similarities.' Vectors of information were formed using the metal composition, followed by the environmental conditions used in each experiments, and finally followed by the crack growth rate (CGR) measured when a sample of pre-cracked metal is set in an environment and the sample is cyclically loaded. Accordingly

  16. Development of Cast Alumina-forming Austenitic Stainless Steel Alloys for use in High Temperature Process Environments

    SciTech Connect

    Muralidharan, Govindarajan; Yamamoto, Yukinori; Brady, Michael P; Pint, Bruce A; Pankiw, Roman; Voke, Don

    2015-01-01

    There is significant interest in the development of alumina-forming, creep resistant alloys for use in various industrial process environments. It is expected that these alloys can be fabricated into components for use in these environments through centrifugal casting and welding. Based on the successful earlier studies on the development of wrought versions of Alumina-Forming Austenitic (AFA) alloys, new alloy compositions have been developed for cast products. These alloys achieve good high-temperature oxidation resistance due to the formation of protective Al2O3 scales while multiple second-phase precipitation strengthening contributes to excellent creep resistance. This work will summarize the results on the development and properties of a centrifugally cast AFA alloy. This paper highlights the strength, oxidation resistance in air and water vapor containing environments, and creep properties in the as-cast condition over the temperature range of 750°C to 900°C in a centrifugally cast heat. Preliminary results for a laboratory cast AFA composition with good oxidation resistance at 1100°C are also presented.

  17. Ultrasonic Spectroscopy of Stainless Steel Sandwich Panels

    NASA Technical Reports Server (NTRS)

    Cosgriff, Laura M.; Lerch, Bradley A.; Hebsur, Mohan G.; Baaklini, George Y.; Ghosn, Louis J.

    2003-01-01

    Enhanced, lightweight material systems, such as 17-4PH stainless steel sandwich panels are being developed for use as fan blades and fan containment material systems for next generation engines. In order to improve the production for these systems, nondestructive evaluation (NDE) techniques, such as ultrasonic spectroscopy, are being utilized to evaluate the brazing quality between the 17-4PH stainless steel face plates and the 17-4PH stainless steel foam core. Based on NDE data, shear tests are performed on sections representing various levels of brazing quality from an initial batch of these sandwich structures. Metallographic characterization of brazing is done to corroborate NDE findings and the observed shear failure mechanisms.

  18. Development of Advanced Corrosion-Resistant Fe-Cr-Ni Austenitic Stainless Steel Alloy with Improved High Temperature Strenth and Creep-Resistance

    SciTech Connect

    Maziasz, PJ

    2004-09-30

    In February of 1999, a Cooperative Research and Development Agreement (CRADA) was undertaken between Oak Ridge National Laboratory (ORNL) and Special Metals Corporation-Huntington Alloys (formerly INCO Alloys International, Inc.) to develop a modified wrought austenitic stainless alloy with considerably more strength and corrosion resistance than alloy 800H or 800HT, but with otherwise similar engineering and application characteristics. Alloy 800H and related alloys have extensive use in coal flue gas environments, as well as for tubing or structural components in chemical and petrochemical applications. The main concept of the project was make small, deliberate elemental microalloying additions to this Fe-based alloy to produce, with proper processing, fine stable carbide dispersions for enhanced high temperature creep-strength and rupture resistance, with similar or better oxidation/corrosion resistance. The project began with alloy 803, a Fe-25Cr-35NiTi,Nb alloy recently developed by INCO, as the base alloy for modification. Smaller commercial developmental alloy heats were produced by Special Metals. At the end of the project, three rounds of alloy development had produced a modified 803 alloy with significantly better creep resistance above 815EC (1500EC) than standard alloy 803 in the solution-annealed (SA) condition. The new upgraded 803 alloy also had the potential for a processing boost in that creep resistance for certain kinds of manufactured components that was not found in the standard alloy. The upgraded 803 alloy showed similar or slightly better oxidation and corrosion resistance relative to standard 803. Creep strength and oxidation/corrosion resistance of the upgraded 803 alloy were significantly better than found in alloy 800H, as originally intended. The CRADA was terminated in February 2003. A contributing factor was Special Metals Corporation being in Chapter 11 Bankruptcy. Additional testing, further commercial scale-up, and any potential

  19. Microstructural Evolution of an Al-Alloyed Duplex Stainless Steel During Tensile Deformation Between 77 K and 473 K (-196 °C and 200 °C)

    NASA Astrophysics Data System (ADS)

    Rahimi, Reza; Ullrich, Christiane; Rafaja, David; Biermann, Horst; Mola, Javad

    2016-06-01

    Tensile deformation behavior of an Al-alloyed Fe-17Cr-6Mn-4Al-3Ni-0.45C (mass pct) duplex stainless steel containing approximately 20 vol pct ferrite was studied in the temperature range from 77 K to 473 K (-196 °C to 200 °C). While the elongation exhibited a maximum near room temperature, the yield strength continuously increased at lower tensile test temperatures. According to the microstructural examinations, the twinning-induced plasticity and the dislocation cell formation were the dominant deformation mechanisms in the austenite and ferrite, respectively. Reduction of the tensile ductility at T < 273 K (0 °C) was attributed to the ready material decohesion at the ferrite/austenite boundaries. Tensile testing at 473 K (200 °C) was associated with the serrated flow which was ascribed to the Portevin-Le Chatelier effect. Due to a rise in the stacking fault energy of austenite, the occurrence of mechanical twinning was impeded at higher tensile test temperatures. Furthermore, the evolution of microstructural constituents at room temperature was studied by interrupted tensile tests. The deformation in the austenite phase started with the formation of Taylor lattices followed by mechanical twinning at higher strains/stresses. In the ferrite phase, on the other hand, the formation of dislocation cells, cell refinement, and microbands formation occurred in sequence during deformation. Microhardness evolution of ferrite and austenite in the interrupted tensile test specimens implied a higher strain-hardening rate for the austenite as it clearly became the harder phase at higher tensile strain levels.

  20. 21 CFR 878.4495 - Stainless steel suture.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Stainless steel suture. 878.4495 Section 878.4495...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture. (a) Identification. A stainless steel suture is a needled or unneedled nonabsorbable surgical suture composed of...

  1. 21 CFR 878.4495 - Stainless steel suture.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Stainless steel suture. 878.4495 Section 878.4495...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture. (a) Identification. A stainless steel suture is a needled or unneedled nonabsorbable surgical suture composed of...

  2. 77 FR 64545 - Drawn Stainless Steel Sinks From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-22

    ... COMMISSION Drawn Stainless Steel Sinks From China Scheduling of the final phase of countervailing duty and... retarded, by reason of subsidized and less-than-fair-value imports from China of drawn stainless steel... merchandise as ``drawn stainless steel sinks with single or multiple drawn bowls, with or without drain...

  3. 77 FR 1504 - Stainless Steel Wire Rod From India

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-10

    ... COMMISSION Stainless Steel Wire Rod From India Determination On the basis of the record \\1\\ developed in the... antidumping duty order on stainless steel wire rod From India would be likely to lead to continuation or... contained in USITC Publication 4300 (January 2012), entitled Stainless Steel Wire Rod From...

  4. 21 CFR 878.4495 - Stainless steel suture.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Stainless steel suture. 878.4495 Section 878.4495...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture. (a) Identification. A stainless steel suture is a needled or unneedled nonabsorbable surgical suture composed of...

  5. 21 CFR 878.4495 - Stainless steel suture.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Stainless steel suture. 878.4495 Section 878.4495...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture. (a) Identification. A stainless steel suture is a needled or unneedled nonabsorbable surgical suture composed of...

  6. 78 FR 21417 - Drawn Stainless Steel Sinks From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... COMMISSION Drawn Stainless Steel Sinks From China Determinations On the basis of the record \\1\\ developed in... drawn stainless steel sinks from China, provided for in subheading 7324.10.00 of the Harmonized Tariff... notification of a preliminary determinations by Commerce that imports of drawn stainless steel sinks from...

  7. 21 CFR 878.4495 - Stainless steel suture.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Stainless steel suture. 878.4495 Section 878.4495...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture. (a) Identification. A stainless steel suture is a needled or unneedled nonabsorbable surgical suture composed of...

  8. Stainless Steel Microstructure and Mechanical Properties Evaluation

    SciTech Connect

    Switzner, Nathan T

    2010-06-01

    A nitrogen strengthened 21-6-9 stainless steel plate was spinformed into hemispherical test shapes. A battery of laboratory tests was used to characterize the hemispheres. The laboratory tests show that near the pole (axis) of a spinformed hemisphere the yield strength is the lowest because this area endures the least “cold-work” strengthening, i.e., the least deformation. The characterization indicated that stress-relief annealing spinformed stainless steel hemispheres does not degrade mechanical properties. Stress-relief annealing reduces residual stresses while maintaining relatively high mechanical properties. Full annealing completely eliminates residual stresses, but reduces yield strength by about 30%.

  9. Friction Drilling of Stainless Steels Pipes

    SciTech Connect

    Fernandez, A.; Lopez de Lacalle, L. N.; Lamikiz, A.

    2011-01-17

    This work describes the experimental study of the friction drilling process in stainless steel by means of an optimization of the machining conditions. For such purpose austenitic stainless steel with different thicknesses were analyzed through controlled tests at different rotation speeds and feed rates. On one hand, the torque and the thrust force were computed and monitorized. On the other hand, the dimensional tolerances of the holes were evaluated, mainly the accuracy of the hole diameter and the burr thickness at different depths. Another topic of interest inherent to this special technique is the temperature level reached during the friction process which is crucial when it comes to development of microstructural transformations.

  10. Creep cavitation in 304 stainless steel

    SciTech Connect

    Chen, I.W.; Argon, A.S.

    1981-01-01

    Creep cavitation in 304 stainless steel at 0.5 T/sub m/ was investigated. Two specially developed techniques were used to study the nucleation and growth of grain-boundary cavities. It was found that cavities nucleated heterogeneously throughout the creep history and those observed were well in their growth stage. Comparison of these observations with the theory for cavity nucleation requires that a high interfacial stress be present. Experiments suggest that such stress concentrations are present in the early stages of boundary sliding, and in additional transients associated with intermittent sliding of boundaries throughout the creep life. It was found that microstructural variations such as those caused by twins which strongly affect initial particle densities on boundaries can alter cavitation behavior drastically. Our results also show that wedge cracks are the result of accelerated linking of growing cavities in the triple point region of stress concentration and are not a separate phenomenon. Furthermore, at higher strain rates growth of cavities can be accelerated by grain boundary sliding. Lastly, evidence is given to support the view that in engineering alloys which contain complex phas constitutents particularly along grain-boundaries, cavitation in long term service is likely to be caused by cavities nucleated in connection with a prior cold forming operation. 15 figures.

  11. Welding Behavior of Free Machining Stainless Steel

    SciTech Connect

    BROOKS,JOHN A.; ROBINO,CHARLES V.; HEADLEY,THOMAS J.; MICHAEL,JOSEPH R.

    2000-07-24

    The weld solidification and cracking behavior of sulfur bearing free machining austenitic stainless steel was investigated for both gas-tungsten arc (GTA) and pulsed laser beam weld processes. The GTA weld solidification was consistent with those predicted with existing solidification diagrams and the cracking response was controlled primarily by solidification mode. The solidification behavior of the pulsed laser welds was complex, and often contained regions of primary ferrite and primary austenite solidification, although in all cases the welds were found to be completely austenite at room temperature. Electron backscattered diffraction (EBSD) pattern analysis indicated that the nature of the base metal at the time of solidification plays a primary role in initial solidification. The solid state transformation of austenite to ferrite at the fusion zone boundary, and ferrite to austenite on cooling may both be massive in nature. A range of alloy compositions that exhibited good resistance to solidification cracking and was compatible with both welding processes was identified. The compositional range is bounded by laser weldability at lower Cr{sub eq}/Ni{sub eq} ratios and by the GTA weldability at higher ratios. It was found with both processes that the limiting ratios were somewhat dependent upon sulfur content.

  12. Dendritic inhomogeneity of stainless maraging steels

    SciTech Connect

    Krasnikova, S.I.; Drobot, A.V.; Shmelev, A.Y.; Vukelich, S.B.

    1986-03-01

    The authors investigated dendritic inhomogeneity in industrial ingots 630 mm (steel I) in diameter and 500 mm (steel II) in diameter. The variation in the degree of dendritic inhomogeneity was investigated over the height of the ingots and across the sections on an MS-46 microprobe. It was established that the elements can be placed in the following order in accordance with the degree of reduction in the liquation factor: titanium, molybdenum, nickel, chromium, and cobalt. Titanium and molybdenum exhibit forward liquation in both steels, and chromium in steel II. The distribution of nickel and chromium in the steel I ingots and cobalt in the steel II ingots is unconventional. Dendritic inhomogeneity, which must be considered in assigning the heat treatment for finished articles, develops during the crystallization of stainless maraging steels.

  13. 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

    ... Steel), Ghent, KY Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as... authority to establish a special-purpose subzone at the stainless steel mill of North American Stainless... subzone status for activity related to the manufacturing and distribution of stainless steel at...

  14. Study of biocompatibility of medical grade high nitrogen nickel-free austenitic stainless steel in vitro.

    PubMed

    Li, Menghua; Yin, Tieying; Wang, Yazhou; Du, Feifei; Zou, Xingzheng; Gregersen, Hans; Wang, Guixue

    2014-10-01

    Adverse effects of nickel ions being released into the living organism have resulted in development of high nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also improves steel properties. The cell cytocompatibility, blood compatibility and cell response of high nitrogen nickel-free austenitic stainless steel were studied in vitro. The mechanical properties and microstructure of this stainless steel were compared to the currently used 316L stainless steel. It was shown that the new steel material had comparable basic mechanical properties to 316L stainless steel and preserved the single austenite organization. The cell toxicity test showed no significant toxic side effects for MC3T3-E1 cells compared to nitinol alloy. Cell adhesion testing showed that the number of MC3T3-E1 cells was more than that on nitinol alloy and the cells grew in good condition. The hemolysis rate was lower than the national standard of 5% without influence on platelets. The total intracellular protein content and ALP activity and quantification of mineralization showed good cell response. We conclude that the high nitrogen nickel-free austenitic stainless steel is a promising new biomedical material for coronary stent development.

  15. The development of alumina-forming austenitic stainless steels for high-temperature structural use

    SciTech Connect

    Brady, Michael P; Yamamoto, Yukinori; Santella, Michael L; Maziasz, Philip J; Pint, Bruce A; Lu, Zhao Ping; Liu, Chain T; Bei, Hongbin

    2008-01-01

    Efforts at Oak Ridge National Laboratory to developAl2O3-forming austenitic (AFA) stainless steels for high-temperature (600-900 aC) structural use under aggressive oxidizing conditions are overviewed. Data obtained to date indicate the potential to achieve superior oxidation resistance to conventional Cr2O3-forming Fe- and Ni-base heat-resistant alloys, with creep strength comparable to state-of-the-art advanced austenitic stainless steels. Preliminary assessment also indicates the developed alloys are amenable to welding. Details of the alloy design approach and composition-microstructure-property relationships are presented.

  16. New hermetic sealing material for vacuum brazing of stainless steels

    NASA Astrophysics Data System (ADS)

    Hildebrandt, S.; Wiehl, G.; Silze, F.

    2016-03-01

    For vacuum brazing applications such as in vacuum interrupter industry Hermetic Sealing Materials (HSM) with low partial pressure are widely used. AgCu28 dominates the hermetic sealing market, as it has a very good wetting behavior on copper and metallized ceramics. Within recent decades wetting on stainless steel has become more and more important. However, today the silver content of HSMs is more in focus than in the past decades, because it has the biggest impact on the material prices. Umicore Technical Materials has developed a new copper based HSM, CuAg40Ga10. The wettability on stainless steel is significantly improved compared to AgCu28 and the total silver content is reduced by almost 44%. In this article the physical properties of the alloy and its brazed joints will be presented compared to AgCu28.

  17. Investigation of Laser Peening Effects on Hydrogen Charged Stainless Steels

    SciTech Connect

    Zaleski, Tania M.

    2008-10-30

    Hydrogen-rich environments such as fuel cell reactors can exhibit damage caused by hydrogen permeation in the form of corrosion cracking by lowering tensile strength and decreasing material ductility. Coatings and liners have been investigated, but there were few shot-peening or laser peening studies referenced in the literature with respect to preventing hydrogen embrittlement. The surface compressive residual stress induced by laser peening had shown success in preventing stress corrosion cracking (SCC) for stainless steels in power plants. The question arose if the residual stresses induced by laser peening could delay the effects of hydrogen in a material. This study investigated the effect of laser peening on hydrogen penetration into metal alloys. Three areas were studied: laser peening, hydrogenation, and hydrogen detection. This study demonstrated that laser peening does not reduce the hydrogen permeation into a stainless steel surface nor does it prevent hydrogen embrittlement. The effect of laser peening to reduce hydrogen-assisted fatigue was unclear.

  18. Failure Assessment of Stainless Steel and Titanium Brazed Joints

    NASA Technical Reports Server (NTRS)

    Flom, Yury A.

    2012-01-01

    Following successful application of Coulomb-Mohr and interaction equations for evaluation of safety margins in Albemet 162 brazed joints, two additional base metal/filler metal systems were investigated. Specimens consisting of stainless steel brazed with silver-base filler metal and titanium brazed with 1100 Al alloy were tested to failure under combined action of tensile, shear, bending and torsion loads. Finite Element Analysis (FEA), hand calculations and digital image comparison (DIC) techniques were used to estimate failure stresses and construct Failure Assessment Diagrams (FAD). This study confirms that interaction equation R(sub sigma) + R(sub tau) = 1, where R(sub sigma) and R(sub t u) are normal and shear stress ratios, can be used as conservative lower bound estimate of the failure criterion in stainless steel and titanium brazed joints.

  19. Kinetic evaluation of intergranular fracture in austenitic stainless steels

    SciTech Connect

    Simonen, E.P.; Bruemmer, S.M.

    1995-12-31

    A second, higher-dose threshold exists for irradiation-assisted stress corrosion cracking (IASCC) of austenitic stainless steels in non-oxidizing environments. The data supporting this concept have stimulated interest in the mechanical aspects of intergranular (IG) fracture. Cracking in a non-oxidizing environment suggests that mechanically-induced IG fracture may play an important role in the IASCC mechanism under these conditions. Radiation alters deformation processes in austenitic alloys and may influence the fracture mode during either in-situ or post-irradiation straining. Radiation effects that must be considered include radiation strengthening, radiation creep and radiation-induced flow localization. The present evaluation relates these radiation-induced phenomena to IG fracture relevant to IASCC. The evaluation indicates that radiation strengthening retards matrix deformation and allows intergranular fracture to occur at higher stresses and lower temperatures than expected for unirradiated stainless steel.

  20. 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

  1. Laser Rewelding of 304L Stainless Steel.

    SciTech Connect

    Maguire, Michael Christopher; Rodelas, Jeffrey

    2016-11-01

    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.

  2. Corrosion study of bare and coated stainless steel

    NASA Technical Reports Server (NTRS)

    Morrison, J. D.

    1972-01-01

    A program was conducted at Kennedy Space Center from February 1968 to February 1971 to evaluate the performance of austenitic stainless steel alloys used in fluid systems lines. For several years, there had been numerous failures of stainless steel hardware caused by pitting and stress corrosion cracking. Several alloys were evaluated for effectiveness of certain sacrificial-type protective coverings in preventing corrosion failures. Samples were tested in specially designed racks placed 91 meters (100 yards) above high-tide line at Cape Kennedy. It is concluded that: (1) unprotected tubing samples showed evidence of pitting initiation after 2 weeks; (2) although some alloys develop larger pits than others, it is probable that the actual pitting rate is independent of alloy type; (3) the deepest pitting occurred in the sheltered part of the samples; and (4) zinc-rich coatings and an aluminum-filled coating have afforded sacrificial protection against pitting for at least 28 months. It is believed that a much longer effective coating life can be expected.

  3. Austenitic stainless steels for cryogenic service

    SciTech Connect

    Dalder, E.N.C.; Juhas, M.C.

    1985-09-19

    Presently available information on austenitic Fe-Cr-Ni stainless steel plate, welds, and castings for service below 77 K are reviewed with the intent (1) of developing systematic relationships between mechanical properties, composition, microstructure, and processing, and (2) of assessing the adequacy of these data bases in the design, fabrication, and operation of engineering systems at 4 K.

  4. Properties of copper?stainless steel HIP joints before and after neutron irradiation

    NASA Astrophysics Data System (ADS)

    Tähtinen, S.; Laukkanen, A.; Singh, B. N.; Toft, P.

    2002-12-01

    The tensile and fracture behaviour of CuCrZr and CuAl25 IG0 alloys joint to 316L(N) stainless steel by hot isostatic pressing (HIP) have been determined in unirradiated and neutron-irradiated conditions. The tensile and fracture behaviour of copper alloy HIP joint specimens are dominated by the properties of the copper alloys, and particularly, by the strength mismatch and mismatch in strain hardening capacities between copper alloys and stainless steel. The test temperature, neutron irradiation and thermal cycles primarily affect the copper alloy HIP joint properties through changing the strength mismatch between the base alloys. Changes in the loading conditions i.e. tensile, bend ( JI) and mixed-mode bend ( JI/ JII) lead to different fracture modes in the copper alloy HIP joint specimens.

  5. Long term corrosion resistance of alumina forming austenitic stainless steels in liquid lead

    NASA Astrophysics Data System (ADS)

    Ejenstam, Jesper; Szakálos, Peter

    2015-06-01

    Alumina forming austenitic steels (AFA) and commercial stainless steels have been exposed in liquid lead with 10-7 wt.% oxygen at 550 °C for up to one year. It is known that chromia forming austenitic stainless steels, such as 316L and 15-15 Ti, have difficulties forming protective oxides in liquid lead at temperatures above 500 °C, which is confirmed in this study. By adding Al to austenitic steels, it is in general terms possible to increase the corrosion resistance. However this study shows that the high Ni containing AFA alloys are attacked by the liquid lead, i.e. dissolution attack occurs. By lowering the Ni content in AFA alloys, it is possible to achieve excellent oxidation properties in liquid lead. Following further optimization of the microstructural properties, low Ni AFA alloys may represent a promising future structural steel for lead cooled reactors.

  6. Aspects of testing and selecting stainless steels for sea water applications

    SciTech Connect

    Steinsmo, U.; Rogne, T.; Drugli, J.M.

    1994-12-31

    In the period from 1980, highly alloyed stainless steels (i.e. Pitting Resistance Equivalent (PRE{sub N}) > 40) have been widely selected for chlorinated sea water systems in the Norwegian offshore industry. Recently failures have been reported -- severe crevice corrosion on flanges in a cooling water system and crevice corrosion at the threaded cast and forged joints in a fire water system. The failures highlights the question of corrosion testing and safe use limits for high alloyed stainless steels in sea water systems. This paper discusses three aspects regarding testing and selection of highly alloyed stainless steels for sea water application -- the relevancy of the electrochemical test methods used, the quality control system and the importance of repassivation.

  7. 75 FR 49467 - Stainless Steel Sheet and Strip in Coils From Taiwan: Preliminary Results and Rescission in Part...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-13

    .... Stainless steel is an alloy steel containing, by weight, 1.2 percent or less of carbon and 10.5 percent or..., aluminum of no less than 5.0 percent, phosphorus of no more than 0.045 percent, sulfur of no more than 0.03... than 0.06 percent, with the balance iron. Permanent magnet iron-chromium-cobalt alloy stainless...

  8. Stress corrosion cracking evaluation of martensitic precipitation hardening stainless steels

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.; Nelson, E. E.

    1980-01-01

    The resistance of the martensitic precipitation hardening stainless steels PH13-8Mo, 15-5PH, and 17-4PH to stress corrosion cracking was investigated. Round tensile and c-ring type specimens taken from several heats of the three alloys were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, to salt spray, and to a seacoast environment. The results indicate that 15-5PH is highly resistant to stress corrosion cracking in conditions H1000 and H1050 and is moderately resistant in condition H900. The stress corrosion cracking resistance of PH13-8Mo and 17-4PH stainless steels in conditions H1000 and H1050 was sensitive to mill heats and ranged from low to high among the several heats included in the tests. Based on a comparison with data from seacoast environmental tests, it is apparent that alternate immersion in 3.5 percent salt water is not a suitable medium for accelerated stress corrosion testing of these pH stainless steels.

  9. Thermal Aging Phenomena in Cast Duplex Stainless Steels

    SciTech Connect

    Byun, T. S.; Yang, Y.; Overman, N. R.; Busby, J. T.

    2015-11-12

    We used cast stainless steels (CASSs)for the large components of light water reactor (LWR) power plants such as primary coolant piping and pump casing. The thermal embrittlement of CASS components is one of the most serious concerns related to the extended-term operation of nuclear power plants. Many past researches have concluded that the formation of Cr-rich alpha-phase by Spinodal decomposition of delta-ferrite phase is the primary mechanism for the thermal embrittlement. Cracking mechanism in the thermally-embrittled duplex stainless steels consists of the formation of cleavage at ferrite and its propagation via separation of ferrite-austenite interphase. This article intends to provide an introductory overview on the thermal aging phenomena in LWR-relevant conditions. Firstly, the thermal aging effect on toughness is discussed in terms of the cause of embrittlement and influential parameters. Moreover, an approximate analysis of thermal reaction using Arrhenius equation was carried out to scope the aging temperatures for the accelerated aging experiments to simulate the 60 and 80 years of services. Further, an equilibrium precipitation calculation was performed for model CASS alloys using the CALPHAD program, and the results are used to describe the precipitation behaviors in duplex stainless steels. Our results are also to be used to guide an on-going research aiming to provide knowledge-based conclusive prediction for the integrity of the CASS components of LWR power plants during the service life extended up to and beyond 60 years.

  10. Thermal Aging Phenomena in Cast Duplex Stainless Steels

    SciTech Connect

    Byun, T. S.; Yang, Y.; Overman, N. R.; Busby, J. T.

    2016-02-28

    Cast stainless steels (CASSs) have been extensively used for the large components of light water reactor (LWR) power plants such as primary coolant piping and pump casing. The thermal embrittlement of CASS components is one of the most serious concerns related to the extended-term operation of nuclear power plants. Many past researches have concluded that the formation of Cr–rich α'-phase by Spinodal decomposition of δ-ferrite phase is the primary mechanism for the thermal embrittlement. Cracking mechanism in the thermally-embrittled duplex stainless steels consists of the formation of cleavage at ferrite and its propagation via separation of ferrite-austenite interphase. This article intends to provide an introductory overview on the thermal aging phenomena in LWR relevant conditions. Firstly, the thermal aging effect on toughness is discussed in terms of the cause of embrittlement and influential parameters. An approximate analysis of thermal reaction using Arrhenius equation was carried out to scope the aging temperatures for the accelerated aging experiments to simulate the 60 and 80 years of services. Further, equilibrium precipitation calculation was performed for model CASS alloys using the CALPHAD program and the results are used to describe the precipitation behaviors in duplex stainless steels. These results are also to be used to guide an on-going research aiming to provide knowledge-based conclusive prediction for the integrity of the CASS components of LWR power plants during the service life extended up to and beyond 60 years.

  11. Thermal Aging Phenomena in Cast Duplex Stainless Steels

    NASA Astrophysics Data System (ADS)

    Byun, T. S.; Yang, Y.; Overman, N. R.; Busby, J. T.

    2016-02-01

    Cast stainless steels (CASSs) have been extensively used for the large components of light water reactor (LWR) power plants such as primary coolant piping and pump casing. The thermal embrittlement of CASS components is one of the most serious concerns related to the extended-term operation of nuclear power plants. Many past researches have concluded that the formation of Cr-rich α'-phase by Spinodal decomposition of δ-ferrite phase is the primary mechanism for the thermal embrittlement. Cracking mechanism in the thermally-embrittled duplex stainless steels consists of the formation of cleavage at ferrite and its propagation via separation of ferrite-austenite interphase. This article intends to provide an introductory overview on the thermal aging phenomena in LWR-relevant conditions. Firstly, the thermal aging effect on toughness is discussed in terms of the cause of embrittlement and influential parameters. An approximate analysis of thermal reaction using Arrhenius equation was carried out to scope the aging temperatures for the accelerated aging experiments to simulate the 60 and 80 years of services. Further, an equilibrium precipitation calculation was performed for model CASS alloys using the CALPHAD program, and the results are used to describe the precipitation behaviors in duplex stainless steels. These results are also to be used to guide an on-going research aiming to provide knowledge-based conclusive prediction for the integrity of the CASS components of LWR power plants during the service life extended up to and beyond 60 years.

  12. Comparison of repassivation kinetics of stainless steels in chloride solution

    NASA Astrophysics Data System (ADS)

    Park, Chan-Jin; Kwon, Hyuk-Sang

    2005-08-01

    Using a rapid scratching electrode technique, the repassivation kinetics of type 304, 316, 444, and 2205 stainless steels (SS) were investigated in a chloride solution. The value of cBV in a log i(t) versus 1/q(t) plot as an effective measure of the repassivation rate was used to compare the reapssivation behaviors among the alloys. During repassivation, lower values of cBV for SS corresponded with faster repassivation rates with the formation of a more protective passive film. In a comparison of repassivation rates based on the alloy's cBV values, the best repassivation behavior was shown by 2205 SS, followed by 444 SS and 316 SS. However, 304 SS exhibited an inflection point in the log i(t) versus 1/q(t) curve, suggesting that dissolution by localized corrosion rather than SCC may occur in the alloy under given conditions.

  13. Crevice and pitting corrosion behavior of stainless steels in seawater

    SciTech Connect

    Zaragoza-Ayala, A.E.; Orozco-Cruz, R.

    1999-11-01

    Pitting and crevice corrosion tests in natural seawater were performed on a series of stainless steels (i.e., S31603, N08904, S32304, S31803, S32520, N08925 and S31266) in order to determine their resistance to these types of localized corrosion. Open circuit potential (OCP) measurements for these alloys show for short exposure times an ennoblement in the OCP. After a certain time, occasional fall and rise in the OCP values was observed, which can be related to nucleation and repassivation of pits and/or crevices on the metal surface. Analysis of the electrochemical behavior and microscopic observations shows that only S31603 and S32304 alloys were susceptible to crevice and pitting corrosion, whereas the remaining alloys exhibited good resistance. Pitting potentials determined by the potentiodynamic technique also show S3 1603 and S32304 are susceptible to pitting corrosion under the experimental conditions used in this work.

  14. Dynamic recrystallization in friction surfaced austenitic stainless steel coatings

    SciTech Connect

    Puli, Ramesh Janaki Ram, G.D.

    2012-12-15

    Friction surfacing involves complex thermo-mechanical phenomena. In this study, the nature of dynamic recrystallization in friction surfaced austenitic stainless steel AISI 316L coatings was investigated using electron backscattered diffraction and transmission electron microscopy. The results show that the alloy 316L undergoes discontinuous dynamic recrystallization under conditions of moderate Zener-Hollomon parameter during friction surfacing. - Highlights: Black-Right-Pointing-Pointer Dynamic recrystallization in alloy 316L friction surfaced coatings is examined. Black-Right-Pointing-Pointer Friction surfacing leads to discontinuous dynamic recrystallization in alloy 316L. Black-Right-Pointing-Pointer Strain rates in friction surfacing exceed 400 s{sup -1}. Black-Right-Pointing-Pointer Estimated grain size matches well with experimental observations in 316L coatings.

  15. Nickel-free stainless steel avoids neointima formation following coronary stent implantation

    NASA Astrophysics Data System (ADS)

    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 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.

  16. Particles, sweat, and tears: a comparative study on bioaccessibility of ferrochromium alloy and stainless steel particles, the pure metals and their metal oxides, in simulated skin and eye contact.

    PubMed

    Hedberg, Yolanda; Midander, Klara; Wallinder, Inger Odnevall

    2010-07-01

    Ferrochromium alloys are manufactured in large quantities and placed on the global market for use as master alloys (secondary raw materials), primarily for stainless steel production. Any potential human exposure to ferrochromium alloy particles is related to occupational activities during production and use, with 2 main exposure routes, dermal contact and inhalation and subsequent digestion. Alloy and reference particles exposed in vitro in synthetic biological fluids relevant for these main exposure routes have been investigated in a large research effort combining bioaccessibility; chemical speciation; and material, surface, and particle characteristics. In this paper, data for the dermal exposure route, including skin and eye contact, will be presented and discussed. Bioaccessibility data have been generated for particles of a ferrochromium alloy, stainless steel grade AISI 316L, pure Fe, pure Cr, iron(II,III)oxide, and chromium(III)oxide, upon immersion in artificial sweat (pH 6.5) and artificial tear (pH 8.0) fluids for various time periods. Measured released amounts of Fe, Cr, and Ni are presented in terms of average Fe and Cr release rates and amounts released per amount of particles loaded. The results are discussed in relation to bulk and surface composition of the particles. Additional information, essential to assess the bioavailability of Cr released, was generated by determining its chemical speciation and by providing information on its complexation and oxidation states in both media investigated. The effect of differences in experimental temperature, 30 degrees C and 37 degrees C, on the extent of metal release in artificial sweat is demonstrated. Iron was the preferentially released element in all test media and for all time periods and iron-containing particles investigated. The extent of metal release was highly pH dependent and was also dependent on the medium composition. Released amounts of Cr and Fe were very low (close to the limit of

  17. Oxidation resistant high creep strength austenitic stainless steel

    DOEpatents

    Brady, Michael P.; Pint, Bruce A.; Liu, Chain-Tsuan; Maziasz, Philip J.; Yamamoto, Yukinori; Lu, Zhao P.

    2010-06-29

    An austenitic stainless steel displaying high temperature oxidation and creep resistance has a composition that includes in weight percent 15 to 21 Ni, 10 to 15 Cr, 2 to 3.5 Al, 0.1 to 1 Nb, and 0.05 to 0.15 C, and that is free of or has very low levels of N, Ti and V. The alloy forms an external continuous alumina protective scale to provide a high oxidation resistance at temperatures of 700 to 800.degree. C. and forms NbC nanocarbides and a stable essentially single phase fcc austenitic matrix microstructure to give high strength and high creep resistance at these temperatures.

  18. An advanced cavitation resistant austenitic stainless steel for pumps

    SciTech Connect

    McCaul, C.

    1996-10-01

    Cavitation damage is a chronic problem leading to impaired pump performance, and eventual failure in a wide range of industrial applications. Pump manufacturers recognize that cavitation damage can be minimized by utilizing advanced hydraulic designs and employing new state-of-the-art materials. The materials solution is particularly attractive because it does not involve detailed engineering studies, new pattern equipment, or long lead times. This paper traces the development, over the past decade, of a new class of cavitation resistant stainless steels. The properties and engineering characteristics of these alloys are described, and several initial field applications are discussed.

  19. 75 FR 26273 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-11

    ... COMMISSION Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From China AGENCY...-fair-value imports from China of certain seamless carbon and alloy steel standard, line, and pressure... than stainless steel) standard, line, and pressure pipes produced to the ASTM A-53, ASTM A-106, ASTM...

  20. Low Temperature Surface Carburization of Stainless Steels

    SciTech Connect

    Collins, Sunniva R; Heuer, Arthur H; Sikka, Vinod K

    2007-12-07

    Low-temperature colossal supersaturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels (SS) without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation. As a result, surface carbon concentrations in excess of 12 at. % are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility. LTCSS is a diffusional surface hardening process that provides a uniform and conformal hardened gradient surface with no risk of delamination or peeling. The treatment retains the austenitic phase and is completely non-magnetic. In addition, because parts are treated at low temperature, they do not distort or change dimensions. During this treatment, carbon diffusion proceeds into the metal at temperatures that constrain substitutional diffusion or mobility between the metal alloy elements. Though immobilized and unable to assemble to form carbides, chromium and similar alloying elements nonetheless draw enormous amounts of carbon into their interstitial spaces. The carbon in the interstitial spaces of the alloy crystals makes the surface harder than ever achieved before by more conventional heat treating or diffusion process. The carbon solid solution manifests a Vickers hardness often exceeding 1000 HV (equivalent to 70 HRC). This project objective was to extend the LTCSS treatment to other austenitic alloys, and to quantify improvements in fatigue, corrosion, and wear resistance. Highlights from the research include the following: • Extension of the applicability of the LTCSS process to a broad range of austenitic and duplex grades of steels • Demonstration of LTCSS ability for a variety of different component shapes and sizes • Detailed microstructural characterization of LTCSS-treated samples of 316L and other alloys

  1. Corrosion of Stainless-Steel Tubing in a Spacecraft Launch Environment

    NASA Technical Reports Server (NTRS)

    Barile, Ronald G.; MacDowell, Louis G.; Curran, Joe; Calle, Luz Maria; Hodge, Timothy

    2001-01-01

    This is a report of exposure of various metal tubing to oceanfront launch environments. The objective is to examine various types of corrosion-resistant tubing for Space Shuttle launch sites. The metals were stainless steels (austenitic, low-carbon, Mo-alloy, superaustenitic, duplex, and superferritic), Ni-Cr-Mo alloy, Ni-Mo-Cr-Fe-W alloy, and austenitic Ni-base superalloy.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  3. Phase Separation in Lean Grade Duplex Stainless Steel 2101

    SciTech Connect

    Garfinkel, D.; Poplawsky, Jonathan D.; Guo, Wei; Young, Jr., George A.; Tucker, Julie

    2015-08-19

    The use of duplex stainless steels (DSS) in nuclear power generation systems is limited by thermal instability that leads to embrittlement in the temperature range of 204°C - 538°C. New lean grade alloys, such as 2101, offer the potential to mitigate these effects. Thermal embrittlement was quantified through impact toughness and hardness testing on samples of alloy 2101 after aging at 427°C for various durations (1-10,000 hours). Additionally, atom probe tomography (APT) was utilized in order to observe the kinetics of α-α’ separation and G-phase formation. Mechanical testing and APT data for two other DSS alloys, 2003 and 2205 were used as a reference to 2101. The results show that alloy 2101 exhibits superior performance compared to the standard grade DSS alloy, 2205, but inferior to the lean grade alloy, 2003, in mechanical testing. APT data demonstrates that the degree of α-α’ separation found in alloy 2101 closely resembles that of 2205, and greatly exceeds 2003. Additionally, contrary to what was observed in 2003, 2101 demonstrated G-phase like precipitates after long aging times, though precipitates were not as abundant as was observed in 2205.

  4. Phase Separation in Lean Grade Duplex Stainless Steel 2101

    DOE PAGES

    Garfinkel, D.; Poplawsky, Jonathan D.; Guo, Wei; ...

    2015-08-19

    The use of duplex stainless steels (DSS) in nuclear power generation systems is limited by thermal instability that leads to embrittlement in the temperature range of 204°C - 538°C. New lean grade alloys, such as 2101, offer the potential to mitigate these effects. Thermal embrittlement was quantified through impact toughness and hardness testing on samples of alloy 2101 after aging at 427°C for various durations (1-10,000 hours). Additionally, atom probe tomography (APT) was utilized in order to observe the kinetics of α-α’ separation and G-phase formation. Mechanical testing and APT data for two other DSS alloys, 2003 and 2205 weremore » used as a reference to 2101. The results show that alloy 2101 exhibits superior performance compared to the standard grade DSS alloy, 2205, but inferior to the lean grade alloy, 2003, in mechanical testing. APT data demonstrates that the degree of α-α’ separation found in alloy 2101 closely resembles that of 2205, and greatly exceeds 2003. Additionally, contrary to what was observed in 2003, 2101 demonstrated G-phase like precipitates after long aging times, though precipitates were not as abundant as was observed in 2205.« less

  5. The stainless steel beneficial reuse integrated demonstration

    SciTech Connect

    Boettinger, W.L.; Lutz, R.N.

    1994-12-31

    Process water heat exchangers at SRS contains over 95% 304 stainless steel which could be recycled back to DOE in a ``controlled release`` manner, that is, the radioactive scrap metal (RSM) could be reprocessed into new reusable products for return to DOE for use within the DOE Complex. In 1994, a demonstration was begun to recycle recycle contaminated stainless steel by melting 60 tons of RSM and refabricating it into containers for long-term temporary storage. The demonstration covers the entire recycle chain; the melting and the fabrication are to be done through subcontracts with private industry. Activity level of RSM to be supplied to industry is less than one curie total; the average specific activity level of the cobalt-60 which will be imbedded in the final products was estimated to be 117 pico curies per gram (4.31 becquerels/gram).

  6. Weldability of Additive Manufactured Stainless Steel

    NASA Astrophysics Data System (ADS)

    Matilainen, Ville-Pekka; Pekkarinen, Joonas; Salminen, Antti

    Part size in additive manufacturing is limited by the size of building area of AM equipment. Occasionally, larger constructions that AM machines are able to produce, are needed, and this creates demand for welding AM parts together. However there is very little information on welding of additive manufactured stainless steels. The aim of this study was to investigate the weldability aspects of AM material. In this study, comparison of the bead on plate welds between AM parts and sheet metal parts is done. Used material was 316L stainless steel, AM and sheet metal, and parts were welded with laser welding. Weld quality was evaluated visually from macroscopic images. Results show that there are certain differences in the welds in AM parts compared to the welds in sheet metal parts. Differences were found in penetration depths and in type of welding defects. Nevertheless, this study presents that laser welding is suitable process for welding AM parts.

  7. Effect of ferrite on cast stainless steels

    SciTech Connect

    Nadezhdin, A.; Cooper, K. ); Timbers, G. . Kraft Pulp Division)

    1994-09-01

    Premature failure of stainless steel castings in bleach washing service is attributed to poor casting quality high porosity and to a high ferrite content, which makes the castings susceptible to corrosion by hot acid chloride solutions. A survey of the chemical compositions and ferrite contents of corrosion-resistant castings in bleach plants at three pulp mills found high [delta]-ferrite levels in the austenitic matrix due to the improper balance between austenite and ferrite stabilizers.

  8. The use of stainless steel crowns.

    PubMed

    Seale, N Sue

    2002-01-01

    The stainless steel crown (SSC) is an extremely durable restoration with several clear-cut indications for use in primary teeth including: following a pulpotomy/pulpectomy; for teeth with developmental defects or large carious lesions involving multiple surfaces where an amalgam is likely to fail; and for fractured teeth. In other situations, its use is less clear cut, and caries risk factors, restoration longevity and cost effectiveness are considerations in decisions to use the SSC. The literature on caries risk factors in young children indicates that children at high risk exhibiting anterior tooth decay and/or molar caries may benefit by treatment with stainless steel crowns to protect the remaining at-risk tooth surfaces. Studies evaluating restoration longevity, including the durability and lifespan of SSCs and Class II amalgams demonstrate the superiority of SSCs for both parameters. Children with extensive decay, large lesions or multiple surface lesions in primary molars should be treated with stainless steel crowns. Because of the protection from future decay provided by their feature of full coverage and their increased durability and longevity, strong consideration should be given to the use of SSCs in children who require general anesthesia. Finally, a strong argument for the use of the SSC restoration is its cost effectiveness based on its durability and longevity.

  9. SRS stainless steel beneficial reuse program

    SciTech Connect

    Boettinger, W.L.

    1997-02-01

    The US Department of Energy`s (DOE) Savannah River Site (SRS) has thousands of tons of stainless steel radioactive scrap metal (RSNI). Much of the metal is volumetrically contaminated. There is no {open_quotes}de minimis{close_quotes} free release level for volumetric material, and therefore no way to recycle the metal into the normal commercial market. If declared waste, the metal would qualify as low level radioactive waste (LLW) and ultimately be dispositioned through shallow land buried at a cost of millions of dollars. The metal however could be recycled in a {open_quotes}controlled release{close_quote} manner, in the form of containers to hold other types of radioactive waste. This form of recycle is generally referred to as {open_quotes}Beneficial Reuse{close_quotes}. Beneficial reuse reduces the amount of disposal space needed and reduces the need for virgin containers which would themselves become contaminated. Stainless steel is particularly suited for long term storage because of its resistance to corrosion. To assess the practicality of stainless steel RSM recycle the SRS Benficial Reuse Program began a demonstration in 1994, funded by the DOE Office of Science and Technology. This paper discusses the experiences gained in this program.

  10. Impact Testing of Stainless Steel Materials

    SciTech Connect

    R. K. Blandford; D. K. Morton; T. E. Rahl; S. D. Snow

    2005-07-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates (10 to 200 per second) during accidental drop events. Mechanical characteristics of these materials under dynamic (impact) loads in the strain rate range of concern are not well documented. The goal of the work presented in this paper was to improve understanding of moderate strain rate phenomena on these materials. Utilizing a drop-weight impact test machine and relatively large test specimens (1/2-inch thick), initial test efforts focused on the tensile behavior of specific stainless steel materials during impact loading. Impact tests of 304L and 316L stainless steel test specimens at two different strain rates, 25 per second (304L and 316L material) and 50 per second (304L material) were performed for comparison to their quasi-static tensile test properties. Elevated strain rate stress-strain curves for the two materials were determined using the impact test machine and a “total impact energy” approach. This approach considered the deformation energy required to strain the specimens at a given strain rate. The material data developed was then utilized in analytical simulations to validate the final elevated stress-strain curves. The procedures used during testing and the results obtained are described in this paper.

  11. 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.

  12. Decontaminating and Melt Recycling Tritium Contaminated Stainless Steel

    SciTech Connect

    Clark, E.A.

    1995-04-03

    The Westinghouse Savannah River Company, Idaho National Engineering Laboratory, and several university and industrial partners are evaluating recycling radioactively contaminated stainless steel. The goal of this program is to recycle contaminated stainless steel scrap from US Department of Energy national defense facilities. There is a large quantity of stainless steel at the DOE Savannah River Site from retired heavy water moderated Nuclear material production reactors (for example heat exchangers and process water piping), that will be used in pilot studies of potential recycle processes. These parts are contaminated by fission products, activated species, and tritium generated by neutron irradiation of the primary reactor coolant, which is heavy (deuterated) water. This report reviews current understanding of tritium contamination of stainless steel and previous studies of decontaminating tritium exposed stainless steel. It also outlines stainless steel refining methods, and proposes recommendations based on this review.

  13. Fracture toughness of irradiated wrought and cast austenitic stainless steels in BWR environment.

    SciTech Connect

    Chopra, O. K.; Gruber, E. E.; Shack, W. J.

    2007-01-01

    In light water reactors, austenitic stainless steels (SSs) are used extensively as structural alloys in reactor core internal components because of their high strength, ductility, and fracture toughness. Exposure to high levels of neutron irradiation for extended periods degrades the fracture properties of these steels by changing the material microstructure (e.g., radiation hardening) and microchemistry (e.g., radiation-induced segregation). We look at the results of a study of simulated light-water reactor coolants, material chemistry, and irradiation damage and their effects on the susceptibility to stress-corrosion cracking of various commercially available and laboratory-melted stainless steels.

  14. Aging degradation of cast stainless steel

    SciTech Connect

    Chopra, O.K.; Chung, H.M.

    1986-10-01

    A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. Microstructures of cast materials subjected to long-term aging either in reactor service or in the laboratory have been characterized by TEM, SANS, and APFIM techniques. Two precipitate phases, i.e., the Cr-rich ..cap alpha..' and Ni- and Si-rich G phase, have been identified in the ferrite matrix of the aged steels. The results indicate that the low-temperature embrittlement is primarily caused by ..cap alpha..' precipitates which form by spinodal decomposition. The relative contribution of G phase to loss of toughness is now known. Microstructural data also indicate that weakening of ferrite/austenite phase boundary by carbide precipitates has a significant effect on the onset and extent of embrittlement of the high-carbon CF-8 and CF-8M grades of stainless steels, particularly after aging at 400 or 450/sup 0/C. Data from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 350, 400, and 450/sup 0/C are presented and correlated with the microstructural results. Thermal aging of the steels results in an increase in tensile strength and a decrease in impact energy, J/sub IC/, and tearing modulus. The fracture toughness results show good agreement with the Charpy-impact data. The effects of compositional and metallurgical variables on loss of toughness are discussed.

  15. A Stem Analysis of Two Rapidly Solidified Stainless Steels.

    DTIC Science & Technology

    1980-03-25

    slightly faster rate than the 303 stainless steel powder and therefore few usable specimens were obtained by electropolishing . The unsuccessful...CONCLUSIONS Rapid solidification processing of a high- sulphur austenitic type 303 stainless steel produces a significant refinement in the...A STEM ANALYSTS OF TWO RAPIDLY SOLIDIFIED STAINLESS STEELS . (U) UN D MAR 80 T F KELLY, J B VANDER SANDE NOBOI-76-C-0171 UNLSSFE7Minrnc UNCLASSIFIED

  16. Characterization of thermal aging of duplex stainless steel by SQUID

    SciTech Connect

    Isobe, Y.; Kamimura, A.; Aoki, K.; Nakayasu, F.

    1995-08-01

    Thermal aging is a growing concern for long-term-aged duplex stainless steel piping in nuclear power plants. Superconducting QUantum Interference Device (SQUID) was used for the detection of thermal aging of SUS329 rolled duplex stainless steel and SCS16 cast duplex stainless steel. It was found that the SQUID output signal pattern in the presence of AC magnetic field applied to the specimen was sensitive to the changes in electromagnetic properties due to thermal aging.

  17. The interaction between nitride uranium and stainless steel

    NASA Astrophysics Data System (ADS)

    Shornikov, D. P.; Nikitin, S. N.; Tarasov, B. A.; Baranov, V. G.; Yurlova, M. S.

    2016-04-01

    Uranium nitride is most popular nuclear fuel for Fast Breeder Reactor New Generation. In-pile experiments at reactor BOR-60 was shown an interaction between nitride fuel and stainless steel in the range of 8-11% burn up (HA). In order to investigate this interaction has been done diffusion tests of 200 h and has been shown that the reaction occurs in the temperature range 1000-1100 ° C. UN interacted with steel in case of high pollution oxygen (1000-2000 ppm). Also has been shown to increase interaction UN with EP-823 steel in the presence of cesium. In this case the interaction layer had a thickness about 2-3 μm. Has been shown minimal interaction with new ODS steel EP-450. The interaction layer had a thickness less then 2 μm. Did not reveal the influence of tellurium and iodine increased interaction. It was show compatibility at 1000 °C between UN and EP-450 ODS steel, chrome steel, alloying aluminium and silicium.

  18. Stainless Steel Leaches Nickel and Chromium into Foods During Cooking

    PubMed Central

    Kamerud, Kristin L.; Hobbie, Kevin A.; Anderson, Kim A.

    2014-01-01

    Toxicological studies show that oral doses of nickel and chromium can cause cutaneous adverse reactions such as dermatitis. Additional dietary sources, such as leaching from stainless steel cookware during food preparation, are not well characterized. This study examined stainless steel grades, cooking time, repetitive cooking cycles, and multiple types of tomato sauces for their effects on nickel and chromium leaching. Trials included three types of stainless steels and a stainless steel saucepan; cooking times of 2 to 20 hours, ten consecutive cooking cycles, and four commercial tomato sauces. After a simulated cooking process, samples were analyzed by ICP-MS for Ni and Cr. After six hours of cooking, Ni and Cr concentrations in tomato sauce increased up to 26- and 7-fold respectively, depending on the grade of stainless steel. Longer cooking durations resulted in additional increases in metal leaching, where Ni concentrations increased 34 fold and Cr increased approximately 35 fold from sauces cooked without stainless steel. Cooking with new stainless steel resulted in the largest increases. Metal leaching decreases with sequential cooking cycles and stabilized after the sixth cooking cycle, though significant metal contributions to foods were still observed. The tenth cooking cycle, resulted in an average of 88 μg of Ni and 86 μg of Cr leached per 126 g serving of tomato sauce. Stainless steel cookware can be an overlooked source of nickel and chromium, where the contribution is dependent on stainless steel grade, cooking time, and cookware usage. PMID:23984718

  19. Stainless steel leaches nickel and chromium into foods during cooking.

    PubMed

    Kamerud, Kristin L; Hobbie, Kevin A; Anderson, Kim A

    2013-10-02

    Toxicological studies show that oral doses of nickel and chromium can cause cutaneous adverse reactions such as dermatitis. Additional dietary sources, such as leaching from stainless steel cookware during food preparation, are not well characterized. This study examined stainless steel grades, cooking time, repetitive cooking cycles, and multiple types of tomato sauces for their effects on nickel and chromium leaching. Trials included three types of stainless steels and a stainless steel saucepan, cooking times of 2-20 h, 10 consecutive cooking cycles, and four commercial tomato sauces. After a simulated cooking process, samples were analyzed by ICP-MS for Ni and Cr. After 6 h of cooking, Ni and Cr concentrations in tomato sauce increased up to 26- and 7-fold, respectively, depending on the grade of stainless steel. Longer cooking durations resulted in additional increases in metal leaching, where Ni concentrations increased 34-fold and Cr increased approximately 35-fold from sauces cooked without stainless steel. Cooking with new stainless steel resulted in the largest increases. Metal leaching decreases with sequential cooking cycles and stabilized after the sixth cooking cycle, although significant metal contributions to foods were still observed. The tenth cooking cycle resulted in an average of 88 μg of Ni and 86 μg of Cr leached per 126 g serving of tomato sauce. Stainless steel cookware can be an overlooked source of nickel and chromium, where the contribution is dependent on stainless steel grade, cooking time, and cookware usage.

  20. Weldment for austenitic stainless steel and method

    DOEpatents

    Bagnall, Christopher; McBride, Marvin A.

    1985-01-01

    For making defect-free welds for joining two austenitic stainless steel mers, using gas tungsten-arc welding, a thin foil-like iron member is placed between the two steel members to be joined, prior to making the weld, with the foil-like iron member having a higher melting point than the stainless steel members. When the weld is formed, there results a weld nugget comprising melted and then solidified portions of the joined members with small portions of the foil-like iron member projecting into the solidified weld nugget. The portions of the weld nugget proximate the small portions of the foil-like iron member which project into the weld nugget are relatively rich in iron. This causes these iron-rich nugget portions to display substantial delta ferrite during solidification of the weld nugget which eliminates weld defects which could otherwise occur. This is especially useful for joining austenitic steel members which, when just below the solidus temperature, include at most only a very minor proportion of delta ferrite.

  1. 77 FR 58355 - Drawn Stainless Steel Sinks From the People's Republic of China: Countervailing Duty Investigation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-20

    ... International Trade Administration Drawn Stainless Steel Sinks From the People's Republic of China... Department'') initiated antidumping and countervailing duty investigations of drawn stainless steel sinks... countervailing duty determination.\\2\\ \\1\\ See Drawn Stainless Steel Sinks From the People's Republic of...

  2. The potential of modified type 310 stainless steel for advanced fossil energy applications

    SciTech Connect

    Swindeman, R.W.

    1992-03-01

    An evaluation was undertaken to determine the potential of modified type 310 stainless steel for fossil energy applications. First, alloy performance criteria for components in several emerging technologies were identified. Then, a brief review of existing alloy technology was undertaken relative to performance criteria. Key issues were the tendency for type 310 stainless steel to embrittle due to the formation of intermetallic phases, the poor resistance of type 310 stainless steel to highly sulfidizing environments, the need to examine the strength and ductility of weldments, and the lack of a long-time data base and criteria for setting allowable stress at temperatures in excess of 800{degrees}C. An activity was outlined that would address several of the key issues.

  3. Substitution for chromium in 304 stainless steel. [effects on oxidation and corrosion resistance

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    An investigation was conducted to determine the effects of substituting less strategic elements for Cr on oxidation and corrosion resistance of AISI 304 stainless steel. 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 33 percent. Two alloys containing 12% Cr plus 2% Al plus 2% Mo and 12% Cr plus 2.65% Si were identified which exhibited oxidation and corrosion resistance comparable to AISI 304 stainless steel.

  4. Microstructure of rapidly solidified Al 2O 3 dispersion strengthened type 316 stainless steel

    NASA Astrophysics Data System (ADS)

    Megusar, J.; Arnberg, L.; Vander Sande, J. B.; Grant, N. J.

    An aluminum oxide dispersion strengthened 316 stainless steel was developed by surface oxidation. Surface oxidation was chosen as a preferred method in order to minimize formation of less stable chromium oxides. Ultra low C+N 316 stainless steel was alloyed with 1 wt% A1, rapidly solidified to produce fine powders and attrited to approximately 0.5 pm thick flakes to provide for surface oxidation. Oxide particles in the extruded material were identified mostly as A1 oxides, In the preirradiated condition, oxide dispersion retarded crystallization and grain growth and had an effect on room temperature tensile properties. These structural modifications are expected to have an effect on the swelling resistance, structure stability and high temperature strength of austenitic stainless steels (Path A alloys).

  5. Superhard Nanocrystalline Homometallic Stainless Steel on Steel for Seamless Coatings

    NASA Technical Reports Server (NTRS)

    Tobin, Eric J.; Hafley, R. (Technical Monitor)

    2002-01-01

    The objective of this work is to deposit nanocrystalline stainless steel onto steel substrates (homometallic) for enhanced wear and corrosion resistance. Homometallic coatings provide superior adhesion, and it has been shown that ultrafine-grained materials exhibit the increased hardness and decreased permeability desired for protective coatings. Nanocrystals will be produced by controlling nucleation and growth and use of an ion beam during deposition by e-beam evaporation or sputtering. Phase I is depositing 31 6L nanocrystalline stainless steel onto 31 6L stainless steel substrates. These coatings exhibit hardnesses comparable to those normally obtained for ceramic coatings such ZrO2, and possess the superior adhesion of seamless, homometallic coatings. Hardening the surface with a similar material also enhances adhesion, by avoiding problems associated with thermal and lattice mismatch. So far we have deposited nanocrystalline homometallic 316L stainless steel coatings by varying the ions and the current density of the ion beams. For all deposition conditions we have produced smooth, uniform, superhard coatings. All coatings exhibit hardness of at least 200% harder than that of bulk materials. Our measurements indicate that there is a direct relationship between nanohardness and the current density of the ion beam. Stress measurements indicate that stress in the films is increasingly proportional to current density of the ion beam. TEM, XPS, and XRD results indicate that the coated layers consist of FCC structure nanocrystallites with a dimension of about 10 to 20 nm. The Ni and Mo concentration of these coating are lower than those of bulk 316L but the concentration of Cr is higher.

  6. Fracture mechanism of borated stainless steel

    SciTech Connect

    He, J.Y.; Soliman, S.E.; Baratta, A.J.; Balliett, T.A.

    2000-05-01

    The mechanical properties and fracture mechanism of irradiated and unirradiated boron containing Type 304 stainless steel are studied. Four different batches with different boron weight percentages are used. One of these batches was manufactured by a conventional wrought technique, while the others were manufactured by a powder metallurgy technique. The irradiated specimens were subjected to a fluence level of 5 x 10{sup 19} or 1 {times} 10{sup 21} n/m{sup 2}. The mechanical and fracture tests were performed at temperatures of 233, 298, and 533 K. No significant effects on the mechanical properties or fracture behavior were observed as a result of neutron irradiation and/or temperature. The ductility and toughness of the borated steel were found to decrease with increasing boron content. The effect of boride on void nucleation and linkage was found to play an important role in the fracture behavior of borated steel.

  7. Weld Properties of a Free Machining Stainless Steel

    SciTech Connect

    J. A. Brooks; S. H. Goods; C. V. Robino

    2000-08-01

    The all weld metal tensile properties from gas tungsten arc and electron beam welds in free machining austenitic stainless steels have been determined. Ten heats with sulfur contents from 0.04 to 0.4 wt.% and a wide range in Creq/Nieq ratios were studied. Tensile properties of welds with both processes were related to alloy composition and solidification microstructure. The yield and ultimate tensile strengths increased with increasing Creq/Nieq ratios and ferrite content, whereas the ductility measured by RA at fracture decreased with sulfur content. Nevertheless, a range in alloy compositions was identified that provided a good combination of both strength and ductility. The solidification cracking response for the same large range of compositions are discussed, and compositions identified that would be expected to provide good performance in welded applications.

  8. Cold Spray Repair of Martensitic Stainless Steel Components

    NASA Astrophysics Data System (ADS)

    Faccoli, M.; Cornacchia, G.; Maestrini, D.; Marconi, G. P.; Roberti, R.

    2014-12-01

    The possibility of using cold spray as repair technique of martensitic stainless steel components was evaluated through laboratory investigations. An austenitic stainless steel feedstock powder was chosen, instead of soft metals powders like nickel, copper, or aluminum, used for repairing components made in light alloy or cast iron. The present study directly compares the microstructure, the residual stresses, and the micro-hardness of repairs obtained by cold spray and by TIG welding, that is commonly used as repair technique in large steel components. XRD and optical metallographic analysis of the repairs showed that cold spray offers some advantages, inducing compressive residual stresses in the repair and avoiding alterations of the interface between repair and base material. For these reasons, a heat treatment after the cold spray repair is not required to restore the base material properties, whereas a post-weld heat treatment is needed after the welding repair. Cold spray repair also exhibits a higher micro-hardness than the welding repair. In addition, the cavitation erosion resistance of a cold spray coating was investigated through ultrasonic cavitation tests, and the samples worn surfaces were observed by scanning electron microscopy.

  9. 3. INTERIOR VIEW OF SMOKEHOUSE UNIT; NOTE STAINLESS STEEL NOZZLES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. INTERIOR VIEW OF SMOKEHOUSE UNIT; NOTE STAINLESS STEEL NOZZLES THAT INTRODUCED SMOKE INTO UNIT; FLOOR IS UNPAINTED STEEL - Rath Packing Company, Smokehouse-Hog Chilling Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  10. Laser surface modification of stainless steels for cavitation erosion resistance

    NASA Astrophysics Data System (ADS)

    Kwok, Chi Tat

    1999-12-01

    Austenitic stainless steel UNS S31603 (Fe -17.6Cr -11.2Ni -2.5Mo -1.4Mn -0.4Si -0.03C) has higher pitting corrosion resistance but lower cavitation erosion resistance than that of UNS S30400. This is because of its lower tendency for strain induced martensitic transformation and higher stacking fault energy as compared with those of UNS S30400. In order to improve its cavitation erosion resistance, surface modification of S31603 was performed by laser surface melting and laser surface alloying using a 2-kW CW Nd-YAG laser and a 3-kW CW CO2 laser. For laser surface melting, austenitic stainless steel UNS S30400, super duplex stainless steel UNS S32760 and martensitic stainless steel UNS S42000 were also investigated for comparison purpose. For laser surface alloying, alloying materials including various elements (Co, Cr, Ni, Mo, Mn, Si & C), alloys (AlSiFe & NiCrSiB), ceramics (Si3N 4, SiC, Cr3C2, TiC, CrB & Cr2O 3) and alloys-ceramics (Co-WC, Ni-WC, Ni-Al2O3, Ni-Cr2C3) were used to modify the surface of S31603. The alloyed surface was achieved first by flame spraying or pre-placing of the alloy powder on the S31603 surface and then followed by laser surface remelting. The cavitation erosion characteristics of laser surface modified specimens in 3.5% NaCl solution at 23°C were studied by means of a 20-kHz ultrasonic vibrator at a peak-to-peak amplitude of 30 mum. In addition, their pitting corrosion behaviour was evaluated by electrochemical techniques. The microstructures, compositions, phase changes and damage mechanisms under cavitation erosion were investigated by optical microscopy, SEM, EDAX and X-ray diffractometry. Mechanical properties such as microhardness profile were also examined. The cavitation erosion resistance Re (reciprocal of the mean depth of penetration rate) of laser surface melted S31603 was found to be improved by 22% and was attributed to the existence of tensile residual stress. Improvement on the Re of S42000 was found to be 8.5 times

  11. Initial tensile test results from J316 stainless steel irradiated in the HFIR spectrally tailored experiment

    SciTech Connect

    Pawel, J.E.; Grossbeck, M.L.; Rowcliffe, A.F.

    1995-04-01

    The objective of this work is to determine the effects of neutron irradiation on the mechanical properties of austenitic stainless steel alloys. In this experiment, the spectrum has been tailored to reduce the thermal neutron flux and achieve a He/dpa level near that expected in a fusion reactor.

  12. Electrochemical Evaluation of Stainless Steels in Acidified Sodium Chloride Solutions

    NASA Technical Reports Server (NTRS)

    Calle, L. M.; MacDowell, L. G.; Vinje, R. D.

    2004-01-01

    This paper presents the results of an investigation in which several 300-series stainless steels (SS): AISI S30403 SS (UNS S30403), AISI 316L SS (UNS S31603), and AISI 317L SS (LINS S31703), as well as highly-alloyed: SS 254-SMO (UNS S32154), AL-6XN (N08367) and AL29-4C (UNS S44735), were evaluated using DC electrochemical techniques in three different electrolyte solutions. The solutions consisted of neutral 3.55% NaCl, 3.55% NaCl in 0.1N HCl, and 3.55% NaCl in 1.0N HCl. These solutions were chosen to simulate environments that are less, similar, and more aggressive, respectively, than the conditions at the Space Shuttle launch pads. The electrochemical test results were compared to atmospheric exposure data and evaluated for their ability to predict the long-term corrosion performance of the subject alloys. The electrochemical measurements for the six alloys indicated that the higher-alloyed SS 254-SMO, AL29-4C, and AL-6XN exhibited significantly higher resistance to localized corrosion than the 300-series SS. There was a correlation between the corrosion performance of the alloys during a two-year atmospheric exposure and the corrosion rates calculated from electrochemical (polarization resistance) measurements.

  13. 75 FR 81309 - Stainless Steel Plate from Belgium, Italy, Korea, South Africa, and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    ... COMMISSION [Investigation Nos. 701-TA-376 and 379 and 731-TA-788, 790-793 (Second Review)] Stainless Steel... stainless steel plate from Belgium and South Africa and the antidumping duty orders on stainless steel plate... steel plate from Belgium and South Africa and/or the antidumping duty orders on stainless steel...

  14. Stress corrosion cracking of duplex stainless steels in caustic solutions

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Ananya

    Duplex stainless steels (DSS) with roughly equal amount of austenite and ferrite phases are being used in industries such as petrochemical, nuclear, pulp and paper mills, de-salination plants, marine environments, and others. However, many DSS grades have been reported to undergo corrosion and stress corrosion cracking in some aggressive environments such as chlorides and sulfide-containing caustic solutions. Although stress corrosion cracking of duplex stainless steels in chloride solution has been investigated and well documented in the literature but the SCC mechanisms for DSS in caustic solutions were not known. Microstructural changes during fabrication processes affect the overall SCC susceptibility of these steels in caustic solutions. Other environmental factors, like pH of the solution, temperature, and resulting electrochemical potential also influence the SCC susceptibility of duplex stainless steels. In this study, the role of material and environmental parameters on corrosion and stress corrosion cracking of duplex stainless steels in caustic solutions were investigated. Changes in the DSS microstructure by different annealing and aging treatments were characterized in terms of changes in the ratio of austenite and ferrite phases, phase morphology and intermetallic precipitation using optical micrography, SEM, EDS, XRD, nano-indentation and microhardness methods. These samples were then tested for general and localized corrosion susceptibility and SCC to understand the underlying mechanisms of crack initiation and propagation in DSS in the above-mentioned environments. Results showed that the austenite phase in the DSS is more susceptible to crack initiation and propagation in caustic solutions, which is different from that in the low pH chloride environment where the ferrite phase is the more susceptible phase. This study also showed that microstructural changes in duplex stainless steels due to different heat treatments could affect their SCC

  15. Coating method enables low-temperature brazing of stainless steel

    NASA Technical Reports Server (NTRS)

    Seaman, F. D.

    1965-01-01

    Gold coated stainless steel tubes containing insulated electrical conductors are brazed at a low temperature to a copper coated stainless steel sealing block with a gold-copper eutectic. This produces an effective seal without using flux or damaging the electrical conductors.

  16. 6. DETAIL VIEW OF SPIN FORM FURNACE FOR STAINLESS STEEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. DETAIL VIEW OF SPIN FORM FURNACE FOR STAINLESS STEEL FABRICATION. STAINLESS STEEL WAS MACHINED IN SIDE A OF THE BUILDING, BEGINNING IN 1957. (4/24/78) - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

  17. 77 FR 23752 - Drawn Stainless Steel Sinks From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-20

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Drawn Stainless Steel Sinks From China Determinations On the basis of the record \\1\\ developed in... (April 2012), entitled Drawn Stainless Steel Sinks from China: Investigation Nos. 701-TA-489 and...

  18. High strength, tough alloy steel

    DOEpatents

    Thomas, Gareth; Rao, Bangaru V. N.

    1979-01-01

    A high strength, tough alloy steel is formed by heating the steel to a temperature in the austenite range (1000.degree.-1100.degree. C.) to form a homogeneous austenite phase and then cooling the steel to form a microstructure of uniformly dispersed dislocated martensite separated by continuous thin boundary films of stabilized retained austenite. The steel includes 0.2-0.35 weight % carbon, at least 1% and preferably 3-4.5% chromium, and at least one other substitutional alloying element, preferably manganese or nickel. The austenite film is stable to subsequent heat treatment as by tempering (below 300.degree. C.) and reforms to a stable film after austenite grain refinement.

  19. Thermal Aging Phenomena in Cast Duplex Stainless Steels

    DOE PAGES

    Byun, T. S.; Yang, Y.; Overman, N. R.; ...

    2015-11-12

    We used cast stainless steels (CASSs)for the large components of light water reactor (LWR) power plants such as primary coolant piping and pump casing. The thermal embrittlement of CASS components is one of the most serious concerns related to the extended-term operation of nuclear power plants. Many past researches have concluded that the formation of Cr-rich alpha-phase by Spinodal decomposition of delta-ferrite phase is the primary mechanism for the thermal embrittlement. Cracking mechanism in the thermally-embrittled duplex stainless steels consists of the formation of cleavage at ferrite and its propagation via separation of ferrite-austenite interphase. This article intends to providemore » an introductory overview on the thermal aging phenomena in LWR-relevant conditions. Firstly, the thermal aging effect on toughness is discussed in terms of the cause of embrittlement and influential parameters. Moreover, an approximate analysis of thermal reaction using Arrhenius equation was carried out to scope the aging temperatures for the accelerated aging experiments to simulate the 60 and 80 years of services. Further, an equilibrium precipitation calculation was performed for model CASS alloys using the CALPHAD program, and the results are used to describe the precipitation behaviors in duplex stainless steels. Our results are also to be used to guide an on-going research aiming to provide knowledge-based conclusive prediction for the integrity of the CASS components of LWR power plants during the service life extended up to and beyond 60 years.« less

  20. THE CLEANING OF 303 STAINLESS STEEL

    SciTech Connect

    Shen, T H

    2004-04-20

    The sulfur found on the surfaces of stainless steel 303 (SS303) after nitric acid passivation originated from the MnS inclusions in the steel. The nitric acid attacked and dissolved these MnS inclusions, and redeposited micron-sized elemental sulfur particles back to the surface. To develop an alternative passivation procedure for SS303, citric and phosphoric acids have been evaluated. The experimental results show neither acid causes a significant amount of sulfur deposit. Thus, these two acids can be used as alternatives to nitric acid passivation for NIF applications. For SS303 previously passivated by nitric acid, NaOH soak can be used as a remedial cleaning process to effectively remove the sulfur deposits.

  1. Delta ferrite-containing austenitic stainless steel resistant to the formation of undesirable phases upon aging

    DOEpatents

    Leitnaker, J.M.

    Austenitic stainless steel alloys containing delta ferrite, such as are used as weld deposits, are protected against the transformation of delta ferrite to sigma phase during aging by the presence of carbon plus nitrogen in a weight percent 0.015 to 0.030 times the volume percent ferrite present in the alloy. The formation of chi phase upon aging is controlled by controlling the Mo content.

  2. Heat treatment giving a stable high temperature micro-structure in cast austenitic stainless steel

    DOEpatents

    Anton, Donald L.; Lemkey, Franklin D.

    1988-01-01

    A novel micro-structure developed in a cast austenitic stainless steel alloy and a heat treatment thereof are disclosed. The alloy is based on a multicomponent Fe-Cr-Mn-Mo-Si-Nb-C system consisting of an austenitic iron solid solution (.gamma.) matrix reinforced by finely dispersed carbide phases and a heat treatment to produce the micro-structure. The heat treatment includes a prebraze heat treatment followed by a three stage braze cycle heat treatment.

  3. Delta ferrite-containing austenitic stainless steel resistant to the formation of undesirable phases upon aging

    DOEpatents

    Leitnaker, James M.

    1981-01-01

    Austenitic stainless steel alloys containing delta ferrite, such as are used as weld deposits, are protected against the transformation of delta ferrite to sigma phase during aging by the presence of carbon plus nitrogen in a weight percent 0.015-0.030 times the volume percent ferrite present in the alloy. The formation of chi phase upon aging is controlled by controlling the Mo content.

  4. Role of nanocrystalline cerium oxide coatings on austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Zhang, Haiying

    Protective nanocrystalline cerium oxide coating has been applied to ASTM grade 304L and 304 austenitic stainless steels to improve its oxidation resistance at elevated temperatures. Experimentally, the selected alloy was exposed to 800°C/1000°C under dry air conditions. Weight changes (DeltaW/A) were monitored as a function of time and the results were compared with uncoated alloys tested under similar conditions. It was found that the oxidation resistances of 304L and 304 stainless steels were significantly improved. A comparison of the oxidation rates indicated that the nanocrystalline cerium oxide coating reduced the rate of oxidation by more than two orders of magnitude. Nevertheless, a comprehensive understanding of the mechanisms responsible for the reduction in the oxidation rate is not clear. Consequently, this work is aimed at investigating the mechanisms involved during scale growth in the presence or absence of nanocrystalline coatings. For this purpose, density functional theory was carried out in order to predict oxygen and iron diffusion microscopic activation energies and reveal the intrinsic characteristics of nanocrystalline coatings. A numerical simulation of corrosion process has also been conducted to predict the corrosion rates of alloys with and without coatings. Hence, the results from simulations are compared with the experimental outcome, and possible explanations are given to account for the reduction in the exhibited oxidation rates. The simulation results will provide a highly valuable tool for the realization of functional nanostructures and architectures "by design", particularly in the development of novel coatings, and a new approach of life assessment.

  5. Attachment of Shiga toxigenic Escherichia coli to stainless steel.

    PubMed

    Rivas, Lucia; Fegan, Narelle; Dykes, Gary A

    2007-04-01

    Shiga toxigenic Escherichia coli (STEC) are important foodborne pathogens causing gastrointestinal disease worldwide. Bacterial attachment to food surfaces, such as stainless steel may lead to cross contamination of foods and subsequent foodborne disease. A variety of STEC isolates, including E. coli O157:H7/H- strains, were grown in planktonic (broth) and sessile (agar) culture, following which initial attachment to stainless steel was determined using epifluorescence microscopy. Experiments were performed to determine whether the number of bacteria attached to stainless steel differed between STEC strains and between the two modes of growth. No relationship was found between STEC strains and the number of bacteria attached to stainless steel. Five STEC strains, including one non-toxigenic O157 isolate, attached in significantly greater (p<0.05) numbers to stainless steel following growth in planktonic culture compared to sessile culture. In contrast, two clinical strains of O157:H7 attached in significantly greater (p<0.05) numbers following growth in sessile culture compared to planktonic culture. Thirteen out of twenty E. coli strains showed no significant difference (p>0.05) in attachment when grown in planktonic or sessile culture. The change of interfacial free energy between the bacterial strains and stainless steel was calculated and the influence of free energy in attachment was determined. Although a significant variation (p<0.05) in free energy values was found between STEC strains, no correlation was found between free energy values and bacterial counts on stainless steel. In addition, no correlation was also found between bacterial hydrophobicity and surface charge values or production of surface structures (type I fimbriae or flagella) (previously determined) with the number of bacteria attached to stainless steel. The results of this study suggest that different growth conditions (planktonic and sessile) can influence the attachment of STEC to

  6. Antibacterial polyelectrolyte micelles for coating stainless steel.

    PubMed

    Falentin-Daudré, Céline; Faure, Emilie; Svaldo-Lanero, Tiziana; Farina, Fabrice; Jérôme, Christine; Van De Weerdt, Cécile; Martial, Joseph; Duwez, Anne-Sophie; Detrembleur, Christophe

    2012-05-08

    In this study, we report on the original synthesis and characterization of novel antimicrobial coatings for stainless steel by alternating the deposition of aqueous solutions of positively charged polyelectrolyte micelles doped with silver-based nanoparticles with a polyanion. The micelles are formed by electrostatic interaction between two oppositely charged polymers: a polycation bearing 3,4-dihydroxyphenylalanine units (DOPA, a major component of natural adhesives) and a polyanion (poly(styrene sulfonate), PSS) without using any block copolymer. DOPA units are exploited for their well-known ability to anchor to stainless steel and to form and stabilize biocidal silver nanoparticles (Ag(0)). The chlorine counteranion of the polycation forms and stabilizes biocidal silver chloride nanoparticles (AgCl). We demonstrate that two layers of micelles (alternated by PSS) doped with silver particles are enough to impart to the surface strong antibacterial activity against gram-negative E. coli. Moreover, micelles that are reservoirs of biocidal Ag(+) can be easily reactivated after depletion. This novel water-based approach is convenient, simple, and attractive for industrial applications.

  7. Citric Acid Passivation of Stainless Steel

    NASA Technical Reports Server (NTRS)

    Yasensky, David; Reali, John; Larson, Chris; Carl, Chad

    2009-01-01

    Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nitric acid per year, and receives many parts from vendors who must also dispose of used nitric acid. Unfortunately, nitric acid presents health and environmental hazards. As a result, several recent industry studies have examined citric acid as an alternative. Implementing a citric acid-based passivation procedure would improve the health and environmental safety aspects of passivation process. However although there is a lack of published studies that conclusively prove citric acid is a technically sound passivation agent. In 2007, NASA's KSC Materials Advisory Working Group requested the evaluation of citric acid in place of nitric acid for passivation of parts at KSC. United Space Alliance Materials & Processes engineers have developed a three-phase test plan to evaluate citric acid as an alternative to nitric acid on three stainless steels commonly used at KSC: UNS S30400, S41000, and S17400. Phases 1 and 2 will produce an optimized citric acid treatment based on results from atmospheric exposure at NASA's Beach Corrosion Facility. Phase 3 will compare the optimized solution(s) with nitric acid treatments. If the results indicate that citric acid passivates as well or better than nitric acid, NASA intends to approve this method for parts used at the Kennedy Space Center.

  8. A metallographic evaluation of the stainless steel-silver solder joint.

    PubMed

    Rogers, O W

    1979-02-01

    A technique has been developed and described for the examination of the interface between dissimilar metals, utilizing electrolytic etching and gold electro-deposition procedures. This procedure permitted etching of both the constituents of the silver solder-stainless steel interface without differential leveling. The grain boundaries at the surface of the stainless steel interface were accentuated by the chemical action of the flux during the joining procedure and the notched grain boundaries influenced the nucleation of the silver solder. No evidence of alloying was found within the resolution of the instruments used.

  9. Thermal conductivity and thermal expansion of stainless steels D9 and HT9

    SciTech Connect

    Leibowitz, L.; Blomquist, R.A.

    1988-01-01

    Renewed interest in the use of metallic fuels in liquid-metal fast breeder reactors has prompted study of the thermodynamic and transport properties of its materials. Two stainless steels are of particular interest because of their good performance under irradiation. These are D9, an austenitic steel, and HT9, a ferritic steel. Thermal conductivity and thermal expansion data for these alloys are of particular interest in assessing in-reactor behavior. Because literature data were inadequate, measurements of these two properties for the two steels were performed and are reported to 1200 K. Of particular interest is the influence on these properties of a phase transition in HT9.

  10. Electrochemical Corrosion Behavior of Spray-Formed Boron-Modified Supermartensitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Zepon, Guilherme; Nogueira, Ricardo P.; Kiminami, Claudio S.; Botta, Walter J.; Bolfarini, Claudemiro

    2017-01-01

    Spray-formed boron-modified supermartensitic stainless steel (SMSS) grades are alloys developed to withstand severe wear conditions. The addition of boron to the conventional chemical composition of SMSS, combined with the solidification features promoted by the spray forming process, leads to a microstructure composed of low carbon martensitic matrix reinforced by an eutectic network of M2B-type borides, which considerably increases the wear resistance of the stainless steel. Although the presence of borides in the microstructure has a very beneficial effect on the wear properties of the alloy, their effect on the corrosion resistance of the stainless steel was not comprehensively evaluated. The present work presents a study of the effect of boron addition on the corrosion resistance of the spray-formed boron-modified SMSS grades by means of electrochemical techniques. The borides fraction seems to have some influence on the repassivation kinetics of the spray-formed boron-modified SMSS. It was shown that the Cr content of the martensitic matrix is the microstructural feature deciding the corrosion resistance of this sort of alloys. Therefore, if the Cr content in the alloy is increased to around 14 wt pct to compensate for the boron consumed by the borides formation, the corrosion resistance of the alloy is kept at the same level of the alloy without boron addition.

  11. Electrochemical Corrosion Behavior of Spray-Formed Boron-Modified Supermartensitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Zepon, Guilherme; Nogueira, Ricardo P.; Kiminami, Claudio S.; Botta, Walter J.; Bolfarini, Claudemiro

    2017-04-01

    Spray-formed boron-modified supermartensitic stainless steel (SMSS) grades are alloys developed to withstand severe wear conditions. The addition of boron to the conventional chemical composition of SMSS, combined with the solidification features promoted by the spray forming process, leads to a microstructure composed of low carbon martensitic matrix reinforced by an eutectic network of M2B-type borides, which considerably increases the wear resistance of the stainless steel. Although the presence of borides in the microstructure has a very beneficial effect on the wear properties of the alloy, their effect on the corrosion resistance of the stainless steel was not comprehensively evaluated. The present work presents a study of the effect of boron addition on the corrosion resistance of the spray-formed boron-modified SMSS grades by means of electrochemical techniques. The borides fraction seems to have some influence on the repassivation kinetics of the spray-formed boron-modified SMSS. It was shown that the Cr content of the martensitic matrix is the microstructural feature deciding the corrosion resistance of this sort of alloys. Therefore, if the Cr content in the alloy is increased to around 14 wt pct to compensate for the boron consumed by the borides formation, the corrosion resistance of the alloy is kept at the same level of the alloy without boron addition.

  12. Fusion welding of a modern borated stainless steel

    SciTech Connect

    Robino, C.V.; Cieslak, M.J.

    1997-01-01

    Experiments designed to assess the fabrication and service weldability of 304B4A borated stainless steel were conducted. Welding procedures and parameters for manual gas tungsten arc (GTA) welding, autogenous electron beam (EB) welding and filler-added EB welding were developed and found to be similar to those for austenitic stainless steels. Following the procedure development, four test welds were produced and evaluated by microstructural analysis and Charpy impact testing. Further samples were used for determination of the postweld heat treatment (PWHT) response of the welds. The fusion zone structure of welds in this alloy consists of primary austenite dendrites with an interdendritic eutectic-like austenite/boride constituent. Welds also show an appreciable partially molten zone that consists of the austenite/boride eutectic surrounding unmelted austenite islands. The microstructure of the EB welds was substantially finer than that of the GTA welds, and boride coarsening was not observed in the solid state heat-affected zone (HAZ) of either weld type. The impact toughness of as-welded samples was found to be relatively poor, averaging less than 10 J for both GTA and EB welds. For fusion zone notched GTA and EB samples and centerline notched EB samples, fracture generally occurred along the boundary between the partially molten and solid-state regions of the HAZ. The results of the PWHT study were very encouraging, with typical values of the impact energy for HAZ notched samples approaching 40 J, or twice the minimum code-acceptable value.

  13. Assessment of thermal embrittlement of cast stainless steels

    SciTech Connect

    Chopra, O.K.; Shack, W.J.

    1994-05-01

    A procedure and correlations are presented for assessing thermal embrittlement and predicting Charpy-impact energy and fracture toughness J-R curve of cast stainless steel components under Light Water Reactor operating conditions from known material information. The ``saturation`` impact strength and fracture toughness of a specific cast stainless steel, i.e., the minimum value that would be achieved for the material after long-term service, is estimated from the chemical composition of the steel. Fracture properties as a function of time and temperature of reactor service are estimated from the kinetics of embrittlement, which are also determined from chemical composition. A common ``predicted lower-bound`` J-R curve for cast stainless steels of unknown chemical composition is also defined for a given grade of steel, ferrite content, and temperature. Examples of estimating fracture toughness of cast stainless steel components during reactor service are presented.

  14. Development of Alumina-Forming Austenitic Stainless Steels

    SciTech Connect

    Yamamoto, Yukinori; Brady, Michael P; Santella, Michael L; Bei, Hongbin; Maziasz, Philip J; Pint, Bruce A

    2008-01-01

    Work in fiscal year 2008 focused on the development of creep-resistant, alumina-forming austenitic (AFA) stainless steel alloys, which exhibit a unique combination of an excellent oxidation resistance via protective alumina (Al2O3) scale formation and high-temperature creep strength through the formation of stable nano-scale MC carbides [1-8]. High levels of Nb additions (> 1 wt.% Nb) and/or Ni additions (25-30 wt.%), at Al levels of 2.5-4 wt.%, were found to correlate with increased upper-temperature limit for Al2O3 scale formation in air ( 900 aC) and air with 10% water vapor ( 800 aC). Creep resistance also showed a strong dependence on the level of Nb additions, and was correlated with volume fraction of MC-type carbides using thermodynamic computational tools. A trial heat of a 50 lb AFA alloy ingot was made using conventional single-melt vacuum techniques, and the alloy was successfully hot-rolled without any cracking [2]. This heat showed good weldability, using filler material of the same alloy.

  15. Effect of Internal Hydrogen on Delayed Cracking of Metastable Low-Nickel Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Papula, Suvi; Talonen, Juho; Todoshchenko, Olga; Hänninen, Hannu

    2014-10-01

    Metastable austenitic stainless steels, especially manganese-alloyed low-nickel grades, may be susceptible to delayed cracking after forming processes. Even a few wppm of hydrogen present in austenitic stainless steels as an inevitable impurity is sufficient to cause cracking if high enough fraction of strain-induced α'-martensite and high residual tensile stresses are present. The role of internal hydrogen content in delayed cracking of several metastable austenitic stainless steels having different alloying chemistries was investigated by means of Swift cup tests, both in as-supplied state and after annealing at 673 K (400 °C). Hydrogen content of the test materials in each state was analyzed with three different methods: inert gas fusion, thermal analysis, and thermal desorption spectroscopy. Internal hydrogen content in as-supplied state was higher in the studied manganese-alloyed low-nickel grades, which contributed to susceptibility of unstable grades to delayed cracking. Annealing of the stainless steels reduced their hydrogen content by 1 to 3 wppm and markedly lowered the risk of delayed cracking. Limiting drawing ratio was improved from 1.4 to 1.7 in grade 204Cu, from 1.7 to 2.0 in grade 201 and from 1.8 to 2.12 in grade 301. The threshold levels of α'-martensite and residual stress for delayed cracking at different hydrogen contents were defined for the test materials.

  16. 75 FR 81308 - Stainless Steel Sheet And Strip From Germany, Italy, Japan, Korea, Mexico, And Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    ... COMMISSION Stainless Steel Sheet And Strip From Germany, Italy, Japan, Korea, Mexico, And Taiwan AGENCY... countervailing duty order on stainless steel sheet and strip from Korea and antidumping duty orders on stainless... on stainless steel sheet and strip from Korea and/or the antidumping duty orders on stainless...

  17. Method for reducing formation of electrically resistive layer on ferritic stainless steels

    SciTech Connect

    Rakowski, James M.

    2013-09-10

    A method of reducing the formation of electrically resistive scale on a an article comprising a silicon-containing ferritic stainless subjected to oxidizing conditions in service includes, prior to placing the article in service, subjecting the article to conditions under which silica, which includes silicon derived from the steel, forms on a surface of the steel. Optionally, at least a portion of the silica is removed from the surface to placing the article in service. A ferritic stainless steel alloy having a reduced tendency to form silica on at least a surface thereof also is provided. The steel includes a near-surface region that has been depleted of silicon relative to a remainder of the steel.

  18. Method for reducing formation of electrically resistive layer on ferritic stainless steels

    DOEpatents

    Rakowski, James M.

    2017-02-28

    A method of reducing the formation of electrically resistive scale on a an article comprising a silicon-containing ferritic stainless subjected to oxidizing conditions in service includes, prior to placing the article in service, subjecting the article to conditions under which silica, which includes silicon derived from the steel, forms on a surface of the steel. Optionally, at least a portion of the silica is removed from the surface to placing the article in service. A ferritic stainless steel alloy having a reduced tendency to form silica on at least a surface thereof also is provided. The steel includes a near-surface region that has been depleted of silicon relative to a remainder of the steel.

  19. Influence of high temperature on corrosion behavior of 304 stainless steel in chloride solutions

    NASA Astrophysics Data System (ADS)

    Ahmed, Saad R.

    2016-11-01

    Despite the excellent performance of stainless steel in diverse application, there are media of exposure may accelerate failure of several stainless steel alloys. The possibility of this failure has to be examined by measuring the effective parameters that may result in corrosion at different rates. The present study has been conducted to examine the effect of exposing specimens of 304 stainless steel to 0.5, 1.0, 1.5 and 2.0 M chloride concentration and 70, 80, and 90 °C. Electrochemical technique of measuring the potentials and currency of the examined system has been used to collect the corrosion data. Microstructure of the specimens is examined using Scanning Electron Microscopy and X- Ray Diffraction. Both of these tests revealed no serious phase change due to exposure even at severe conditions. The potentials gained show significant effect of the operation conditions.

  20. Use of 254 SMO (UNS S31254) austenitic stainless steel in tall oil applications

    SciTech Connect

    Davison, R.M.; Redmond, J.D.

    1988-01-01

    In tall oil distillation, as in virtually all systems in pul and paper mills, there is a long term trend to increasingly aggressive corrosion conditions. Factors contributing to this trend include increasing plant size, steps taken to comply with effluent regulation, and the ongoing effort to increase production efficiency. It has long been known that a 6Mo stainless steel or nickel-base alloy resists the very aggressive conditions in the tall oil distillation column, but no such grade has been available for economical construction. The availability and favorable experience with a 6Mo austenitic stainless steel, S31254, in pulp bleaching service suggest potential savings in maintenance costs and in increased production efficiency. This paper characterizes S31254 and discusses field experience in selection of advanced stainless steels for tall oil distillation service.

  1. Prospects of increasing the strength of aluminum by reinforcing it with stainless steel wire (a review)

    NASA Technical Reports Server (NTRS)

    Botvina, L. R.; Ivanova, V. S.; Kopev, I. M.

    1982-01-01

    The theoretical and experimental strength of aluminum reinforced with stainless steel wire is analyzed. Various methods of producing the composite material and it's static and cyclical strengths are considered. The reinforcement of aluminum with stainless steel wire was accomplished from the perspective of increasing the specific strength of aluminum and it's alloys, increasing the strength of the material with respect to high and low temperatures, as well as increasing the cyclical strength. The production of the composite aluminum-stainless steel wire material with approximated or calculated strengthening is possible by any of the considered methods. The selection of the proper production technology depends on precise details and conditions of application of the material.

  2. Development of (Mn,Co)3O4 Protection Layers for Ferritic Stainless Steel Interconnects

    SciTech Connect

    Yang, Zhenguo; Simner, Steven P.; Singh, Prabhakar; Xia, Guanguang; Stevenson, Jeffry W.

    2005-07-05

    A spinel-based surface protection layer has been developed for alloy SOFC current collectors and bi-polar gas separators. The (Mn,Co)3O4 spinel with a nominal composition of Mn1.5Co1.5O4 demonstrates an excellent electrical conductivity and thermal expansion match to ferritic stainless steel interconnects. A slurry-coating technique provides a viable approach for fabricating protective layers of the spinel onto the steel interconnects. Thermally grown protection layers of Mn1.5Co1.5O4 have been found not only to significantly decrease the contact resistance between a LSF cathode and stainless steel interconnect, but also inhibits the sub-scale growth on the stainless steel. The combination of the inhibited sub-scale growth, good thermal expansion matching between the spinel and the stainless steel, and the closed-pore structure contribute to the excellent structural and thermomechanical stability of these spinel protection layers, which was verified by a long-term thermal-cycling test. The spinel protection layers can also act effectively to prevent outward diffusion of chromium from the interconnect alloy, preventing subsequent chromium migration into the cathode and contact materials. PNNL is currently engaged in studies intended to optimize the composition, microstructure, and fabrication procedure for the spinel protection layers.

  3. 76 FR 1599 - Stainless Steel Bar From Brazil: Final Results of Antidumping Duty Administrative Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-11

    ... International Trade Administration Stainless Steel Bar From Brazil: Final Results of Antidumping Duty... results of its administrative review of the antidumping duty order on stainless steel bar from Brazil. The... stainless steel bar (SSB) from Brazil. See Stainless Steel Bar From Brazil: Preliminary Results...

  4. Chemical composition of passive films on AISI 304 stainless steel

    SciTech Connect

    Lorang, G.; Da Cunha Belo, M. ); Simoes, A.M.P.; Ferreira, M.G.S. . Dept. de Engenharia Quimica)

    1994-12-01

    Chemical characterization of passive films formed on AISI 304 austenitic stainless steel, in a borate/boric acid solution at pH 9.2, under various conditions of potential, temperature, and polarizations time, was made by Auger electron spectroscopy combined with ion sputtering, and x-ray photoelectron spectroscopy (XPS). The depth chemical composition, thickness, and duplex character of the passive layers were determined after processing AES sputter profiles by their quantitative approach based on the sequential layer sputtering model. Moreover, separated contributions of elements in their oxidized and unoxidized state could be disclosed from part to part of the oxide-alloy interface. The XPS study specified the chemical bondings which take placed inside the film, between Fe and oxygen (and water).

  5. Impact of a nickel-reduced stainless steel implant on striated muscle microcirculation: a comparative in vivo study.

    PubMed

    Kraft, C N; Burian, B; Perlick, L; Wimmer, M A; Wallny, T; Schmitt, O; Diedrich, O

    2001-12-05

    The impairment of skeletal muscle microcirculation by a biomaterial may have profound consequences. With moderately good physical and corrosion characteristics, implant-quality stainless steel is particularly popular in orthopedic surgery. However, due to the presence of a considerable amount of nickel in the alloy, concern has been voiced in respect to local tissue responses. More recently a stainless steel alloy with a significant reduction of nickel has become commercially available. We, therefore, studied in vivo nutritive perfusion and leukocytic response of striated muscle to this nickel-reduced alloy, and compared these results with those of the materials conventional stainless steel and titanium. Using the hamster dorsal skinfold chamber preparation and intravital microscopy, we could demonstrate that reduction of the nickel quantity in a stainless steel implant has a positive effect on local microvascular parameters. Although the implantation of a conventional stainless steel sample led to a distinct and persistent activation of leukocytes combined with disruption of the microvascular endothelial integrity, marked leukocyte extravasation, and considerable venular dilation, animals with a nickel-reduced stainless steel implant showed only a moderate increase of these parameters, with a clear tendency of recuperation. Titanium implants merely caused a transient increase of leukocyte-endothelial cell interaction within the first 120 min, and no significant change in macromolecular leakage, leukocyte extravasation, or venular diameter. Pending biomechanical and corrosion testing, nickel-reduced stainless steel may be a viable alternative to conventional implant-quality stainless steel for biomedical applications. Concerning tolerance by the local vascular system, titanium currently remains unsurpassed.

  6. Study of residual stress distribution in the machined stainless steel components

    NASA Astrophysics Data System (ADS)

    Jang, Dong Y.; Liou, J.; Cho, U.

    1994-07-01

    The demand for high quality and fully automated production, coupled with advances in alloy development, focuses attention on the surface condition of products, especially the residual stresses on the machined surface because of its effect on component performance, longevity, and reliability. Although stainless steel is an important material with wide application, it is not easy to obtain a favorable surface condition due to its sensitivity to thermal and mechanical operations. In order to obtain favorable surface conditions in a stainless steel component, it is necessary to have practical data which include information concerning tool wear, surface roughness and surface residual stress. In the research toward developing a machinability chart which can provide suitable cutting parameters for the high production rate and good quality surface, and can be used in computer controlled machining tools, surface residual stress distributions in the turning process for stainless steel were studied. Austenitic 304 stainless steel bars were selected as the workpieces and uncoated carbide tools were used in the tests. The obtained results will show residual stress conditions on the machined stainless steel components varying according to cutting conditions.

  7. Nickel release from nickel-plated metals and stainless steels.

    PubMed

    Haudrechy, P; Foussereau, J; Mantout, B; Baroux, B

    1994-10-01

    Nickel release from nickel-plated metals often induces allergic contact dermatitis, but, for nickel-containing stainless steels, the effect is not well-known. In this paper, AISI 304, 316L, 303 and 430 type stainless steels, nickel and nickel-plated materials were investigated. 4 tests were performed: patch tests, leaching experiments, dimethylglyoxime (DMG) spot tests and electrochemical tests. Patch tests showed that 96% of the patients were intolerant to Ni-plated samples, and 14% to a high-sulfur stainless steel (303), while nickel-containing stainless steels with a low sulfur content elicited no reactions. Leaching experiments confirmed the patch tests: in acidic artificial sweat, Ni-plated samples released about 100 micrograms/cm2/week of nickel, while low-sulfur stainless steels released less than 0.03 microgram/cm2/week of nickel, and AISI 303 about 1.5 micrograms/cm2/week. Attention is drawn to the irrelevance of the DMG spot test, which reveals Ni present in the metal bulk but not its dissolution rate. Electrochemical experiments showed that 304 and 316 grades remain passive in the environments tested, while Ni-plated steels and AISI 303 can suffer significant cation dissolution. Thus, Ni-containing 304 and 316 steels should not induce contact dermatitis, while 303 should be avoided. A reliable nitric acid spot test is proposed to distinguish this grade from other stainless steels.

  8. 76 FR 87 - Grant of Authority for Subzone Status; ThyssenKrupp Steel and Stainless USA, LLC; (Stainless and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-03

    ... Foreign-Trade Zones Board Grant of Authority for Subzone Status; ThyssenKrupp Steel and Stainless USA, LLC; (Stainless and Carbon Steel Products) Calvert, AL Pursuant to its authority under the Foreign-Trade Zones Act... establish a special- purpose subzone at the stainless and carbon steel products manufacturing facility...

  9. Materials compatibility of hydride storage materials with austenitic stainless steels

    SciTech Connect

    Clark, E.A.

    1992-09-21

    This task evaluated the materials compatibility of LaNi[sub 5-x]Al[sub x] (x= 0.3, 0.75) hydrides and palladium coated kieselguhr with austenitic stainless steel in hydrogen and tritium process environments. Based on observations of retired prototype hydride storage beds and materials exposure testing samples designed for this study, no materials compatibility problem was indicated. Scanning electron microscopy observations of features on stainless steel surfaces after exposure to hydrides are also commonly found on as-received materials before hydriding. These features are caused by either normal heat treating and acid cleaning of stainless steel or reflect the final machining operation.

  10. Materials compatibility of hydride storage materials with austenitic stainless steels

    SciTech Connect

    Clark, E.A.

    1992-09-21

    This task evaluated the materials compatibility of LaNi{sub 5-x}Al{sub x} (x= 0.3, 0.75) hydrides and palladium coated kieselguhr with austenitic stainless steel in hydrogen and tritium process environments. Based on observations of retired prototype hydride storage beds and materials exposure testing samples designed for this study, no materials compatibility problem was indicated. Scanning electron microscopy observations of features on stainless steel surfaces after exposure to hydrides are also commonly found on as-received materials before hydriding. These features are caused by either normal heat treating and acid cleaning of stainless steel or reflect the final machining operation.

  11. [Study on biocompatibility of MIM 316L stainless steel].

    PubMed

    Wang, Guohui; Zhu, Shaihong; Li, Yiming; Zhao, Yanzhong; Zhou, Kechao; Huang, Boyun

    2007-04-01

    This study was aimed to evaluate the biocompatibility of metal powder injection molding (MIM) 316L stainless steel. The percentage of S-period cells was detected by flow cytometry after L929 cells being incubated with extraction of MIM 316L stainless steel, and titanium implant materials for clinical application were used as control. In addition, both materials were implanted in animals and the histopathological evaluations were carried out. The statistical analyses show that there are no significant differences between the two groups (P > 0.05), which demonstrate that MIM 316L stainless steel has good biocompatibility.

  12. Microbial-Influenced Corrosion of Corten Steel Compared with Carbon Steel and Stainless Steel in Oily Wastewater by Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    Mansouri, Hamidreza; Alavi, Seyed Abolhasan; Fotovat, Meysam

    2015-07-01

    The microbial corrosion behavior of three important steels (carbon steel, stainless steel, and Corten steel) was investigated in semi petroleum medium. This work was done in modified nutrient broth (2 g nutrient broth in 1 L oily wastewater) in the presence of Pseudomonas aeruginosa and mixed culture (as a biotic media) and an abiotic medium for 2 weeks. The behavior of corrosion was analyzed by spectrophotometric and electrochemical methods and at the end was confirmed by scanning electron microscopy. The results show that the degree of corrosion of Corten steel in mixed culture, unlike carbon steel and stainless steel, is less than P. aeruginosa inoculated medium because some bacteria affect Corten steel less than other steels. According to the experiments, carbon steel had less resistance than Corten steel and stainless steel. Furthermore, biofilm inhibits separated particles of those steels to spread to the medium; in other words, particles get trapped between biofilm and steel.

  13. Photoelectrochemical protection of stainless alloys from the stress-corrosion cracking in BWR primary coolant environment

    SciTech Connect

    Akashi, Masatsune; Iso-o, Hiroyuki; Kubota, Nobuhiko; Fukuda, Takanori; Ayabe, Muneo; Hirano, Kenji

    1995-12-31

    The feasibility of counteracting or preventing the stress-corrosion cracking in the BWR core internals by the photoelectrochemical method has been examined. For the purpose TiO{sub 2} semiconductor is noted for its capability of photo electrochemically inducing the water-oxidizing anodic reaction in low enough potential domain if supplied with a light of a wavelength shorter than 410 nm. This paper offers an empirical proof by showing that Type 304 stainless steel and Alloy 600 stainless alloy that have been plasma-spray coated with TiO{sub 2} film will do quite well in environments of BWR primary coolant.

  14. Automatic Welding of Stainless Steel Tubing

    NASA Technical Reports Server (NTRS)

    Clautice, W. E.

    1978-01-01

    To determine if the use of automatic welding would allow reduction of the radiographic inspection requirement, and thereby reduce fabrication costs, a series of welding tests were performed. In these tests an automatic welder was used on stainless steel tubing of 1/2, 3/4, and 1/2 inch diameter size. The optimum parameters were investigated to determine how much variation from optimum in machine settings could be tolerate and still result in a good quality weld. The process variables studied were the welding amperes, the revolutions per minute as a function of the circumferential weld travel speed, and the shielding gas flow. The investigation showed that the close control of process variables in conjunction with a thorough visual inspection of welds can be relied upon as an acceptable quality assurance procedure, thus permitting the radiographic inspection to be reduced by a large percentage when using the automatic process.

  15. Systematic Microstructural and Corrosion Performance Evaluation of CK-3MCuN and CN-3MN High Molybdenum Stainless Steel Castings

    SciTech Connect

    C.D. Lundin; S. Wen; W. Liu; G. Zhou

    2001-10-01

    High molybdenum austenitic stainless steel castings are widely accepted for their high strength, excellent weldability, and good corrosion resistance over a wide range of temperatures in highly oxidizing aqueous and gaseous media in chemical processing and other environments. With their desirable performance, high molybdenum austenitic stainless steel castings are increasingly applied in industry in a similar manner as wrought materials. In general, cast and wrought stainless and high alloy steels are anticipated to possess equivalent resistance to corrosive media, and they are frequently used in conjunction with each other. However, alloying element segregation usually is more evident in castings than in wrought counterparts. Segregation of alloying elements can lead to the formation of secondary phases, such as sigma. Mechanical properties and especially the corrosion resistance of castings may be affected by the secondary phases. In addition, improper heat treatment procedures c an also lead to the formation of carbides and secondary phases in high alloy and austenitic stainless steels.

  16. Stainless steel anodes for alkaline water electrolysis and methods of making

    SciTech Connect

    Soloveichik, Grigorii Lev

    2014-01-21

    The corrosion resistance of stainless steel anodes for use in alkaline water electrolysis was increased by immersion of the stainless steel anode into a caustic solution prior to electrolysis. Also disclosed herein are electrolyzers employing the so-treated stainless steel anodes. The pre-treatment process provides a stainless steel anode that has a higher corrosion resistance than an untreated stainless steel anode of the same composition.

  17. Modeling Hardenable Stainless Steels Using Calculated Martensite Start Temperatures in Thermodynamic Equilibrium Calculations

    NASA Astrophysics Data System (ADS)

    Seifert, Merlin; Theisen, Werner

    2016-12-01

    In this work, martensite start temperatures of several martensitic stainless steels containing different amounts and types of carbides were calculated by means of thermodynamic equilibrium calculations. Two different equations were introduced into the Thermo-Calc® software. The calculations were performed for the respective compositions at austenitization temperature and compared to martensite start temperatures measured using a quenching dilatometer. The purpose was to estimate hardenability and hardness of newly developed steels. Even though the equations used were determined empirically for specific alloying systems, general trends for the investigated steels were found to be reproduced very well. Thus, the comparison of martensite start temperatures of different steels in comparable alloying systems is highly effective for modeling new steels and for predicting their hardenability.

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

    SciTech Connect

    Prajitno, Djoko Hadi

    2015-09-30

    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 relatively 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.

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

    NASA Astrophysics Data System (ADS)

    Prajitno, Djoko Hadi

    2015-09-01

    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 ZrO2. The corrosion stainless steel in nanofluid contains adm+0.01 gpl ZrO2 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 ZrO2 nanoparticle was actively corroded. The value of cathodic Tafel slope stainless steel in nanofluid at different scan rate relatively 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.

  20. A new constitutive model for nitrogen austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Fréchard, S.; Lichtenberger, A.; Rondot, F.; Faderl, N.; Redjaïmia, A.; Adoum, M.

    2003-09-01

    Quasi-static, quasi-dynamic and dynamic compression tests have been performed on a nitrogen alloyed austenitic stainless steel. For all strain rates, a high strain hardening rate and a good ductility have been achieved. In addition, this steel owns a great strain rate sensitivity. The temperature sensitivity bas been determined between 20°C and 400°C. Microstructural analysis has been performed after different loading conditions in relation to the behaviour of the material. Johnson-Cook and Zerilli-Armstrong models have been selected to fit the experimental data into constitutive equations. These models do not reproduce properly the behaviour of this type of steel over the complete range. A new constitutive model that fits very well all the experimental data at different strain, strain rate and temperature has been determined. The model is based on empirical considerations on the separated influence of the main parameters. Single Taylor tests have been realized to validate the models. Live observations of the specimen during impact have been achieved using a special CCD camera set-up. The overall profile at different times are compared to numerical predictions using LS-DYNA code.

  1. Development of Alumina-Forming Austenitic Stainless Steels

    SciTech Connect

    Brady, Michael P; Yamamoto, Yukinori; Bei, Hongbin; Santella, Michael L; Maziasz, Philip J

    2009-01-01

    This paper presents the results of the continued development of creep-resistant, alumina-forming austenitic (AFA) stainless steel alloys, which exhibit a unique combination of excellent oxidation resistance via protective alumina (Al2O3) scale formation and high-temperature creep strength through the formation of stable nano-scale MC carbides and intermetallic precipitates. Efforts in fiscal year 2009 focused on the characterization and understanding of long-term oxidation resistance and tensile properties as a function of alloy composition and microstructure. Computational thermodynamic calculations of the austenitic matrix phase composition and the volume fraction of MC, B2-NiAl, and Fe2(Mo,Nb) base Laves phase precipitates were used to interpret oxidation behavior. Of particular interest was the enrichment of Cr in the austenitic matrix phase by additions of Nb, which aided the establishment and maintenance of alumina. Higher levels of Nb additions also increased the volume fraction of B2-NiAl precipitates, which served as an Al reservoir during long-term oxidation. Ageing studies of AFA alloys were conducted at 750 C for times up to 2000 h. Ageing resulted in near doubling of yield strength at room temperature after only 50 h at 750 C, with little further increase in yield strength out to 2000 h of ageing. Elongation was reduced on ageing; however, levels of 15-25% were retained at room temperature after 2000 h of total ageing.

  2. Evaluation of Oxidation and Hydrogen Permeation of Al Containing Duplex Stainless Steels

    SciTech Connect

    Adams, Thad M.; Korinko, Paul; Duncan, Andrew

    2005-06-17

    As the National Hydrogen Economy continues to develop and evolve the need for structural materials that can resist hydrogen assisted degradation will become critical. To date austenitic stainless steel materials have been shown to be mildly susceptible to hydrogen attack which results in lower mechanical and fracture strengths. As a result, hydrogen permeation barrier coatings are typically applied to these steel to retard hydrogen ingress. The focal point of the reported work was to evaluate the potential for intentional alloying of commercial 300-series stainless steels to promote hydrogen permeation resistant oxide scales. Previous research on the Cr- and Fe-oxide scales inherent to 300-series stainless steels has proven to be inconsistent in effecting permeation resistance. The approach undertaken in this research was to add aluminum to the 300-series stainless steels in an attempt to promote a pure Al-oxide or and Al-rich oxide scale. Aloxide had been previously demonstrated to be an effective hydrogen permeation barrier. Results for 304L and 347H alloys doped with Al in concentration from 0.5-3.0 wt% with respect to oxidation kinetic studies, cyclic oxidation and characterization of the oxide scale chemistry are reported herein. Gaseous hydrogen permeation testing of the Al-doped alloys in both the unoxidized and oxidized (600 C, 30 mins) conditions are reported. A critical finding from this work is that at concentration as low as 0.5 wt% Al, the Al stabilizes the ferrite phase in these steels thus producing duplex austenitic-ferritic microstructures. As the Al-content increases the amount of measured ferrite increases thus resulting in hydrogen permeabilities more closely resembling ferritic steels.

  3. Evaluation of stainless steels for their resistance to intergranular corrosion

    NASA Astrophysics Data System (ADS)

    Korostelev, A. B.; Abramov, V. Ya.; Belous, V. N.

    1996-10-01

    Austenitic stainless steels are being considered as structural materials for first wall/blanket systems in the International Thermonuclear Reactor (ITER). The uniform corrosion of stainless steels in water is well known and is not a critical issue limiting its application for the ITER design. The sensitivity of austenitic steels to intergranular corrosion (IGC) can be estimated rather accurately by means of calculation methods, considering structure and chemical composition of steel. There is a maximum permissible carbon content level, at which sensitization of stainless steel is eliminated: K = Cr eff - αC eff, where α-thermodynamic coefficient, Cr eff-effective chromium content (regarding molybdenum influence) and C eff-effective carbon content (taking into account nickel and stabilizing elements). Corrosion tests for 16Cr11Ni3MoTi, 316L and 316LN steel specimens, irradiated up to 2 × 10 22 n/cm 2 fluence have proved the effectiveness of this calculation technique for determination of austenitic steels tendency to IGC. This method is directly applicable in austenitic stainless steel production and enables one to exclude complicated experiments on determination of stainless steel susceptibility to IGC.

  4. Structure and mechanical properties of improved cast stainless steels for nuclear applications

    NASA Astrophysics Data System (ADS)

    Kenik, E. A.; Busby, J. T.; Gussev, M. N.; Maziasz, P. J.; Hoelzer, D. T.; Rowcliffe, A. F.; Vitek, J. M.

    2017-01-01

    Casting of stainless steels is a promising and cost saving way of directly producing large and complex structures, such a shield modules or divertors for the ITER. In the present work, a series of modified high-nitrogen cast stainless steels has been developed and characterized. The steels, based on the cast equivalent of the composition of 316 stainless steel, have increased N (0.14-0.36%) and Mn (2-5.1%) content; copper was added to one of the heats. Mechanical tests were conducted with non-irradiated and 0.7 dpa neutron irradiated specimens. It was established that alloying by nitrogen significantly improves the yield stress of non-irradiated steels and the deformation hardening rate. Manganese tended to decrease yield stress but increased radiation hardening. The role of copper on mechanical properties was negligibly small. Analysis of structure was conducted using SEM-EDS and the nature and compositions of the second phases and inclusions were analyzed in detail. No ferrite formation or significant precipitation were observed in the modified steels. It was shown that the modified steels, compared to reference material (commercial cast 316L steel), had better strength level, exhibit significantly reduced elemental inhomogeneity and only minor second phase formation.

  5. The effect of stainless steel overlay cladding on corrosion fatigue crack propagation in pressure vessel steel in PWR primary coolant

    SciTech Connect

    Bramwell, I.L.; Tice, D.R.; Worswick, D.; Heys, G.B.

    1995-12-31

    The growth of sub-critical cracks in pressure boundary materials in light water reactors is assessed using codified procedures, but the presence of the overlay-welded stainless steel cladding on the pressure vessel is not normally taken into consideration because of the difficulty in demonstrating clad integrity for the lifetime of the plant. In order to investigate any possible effect of the cladding layer on crack propagation, tests have been performed using two types of specimen. The first was sputter ion plated with a thin layer of austenitic stainless steel to simulate the electrochemical and oxide effects due to the cladding, whilst the second used an overlay clad specimen to investigate the behavior of a crack propagating from the austenitic into the ferritic material. Testing was carried out under cyclic loading conditions in well controlled simulated PWR primary water. At 288 C, the presence of stainless steel in contact with the low alloy steel did not enhance crack propagation in PWR primary coolant compared to unclad or unplated specimens. There was limited evidence that at 288 C under certain loading conditions, in both air and PWR water, there may be an effect of the cladding which reduces crack growth rates, at least for a short distance of crack propagation into the low alloy steel. Crack growth rates in the ferritic steel at 130 C were higher for both the plated and clad specimens than found in previous tests under similar conditions on the unclad material. However, the crack growth rates were bounded by current ASME 11 Appendix A recommendations for defects exposed to water and at low R ratio. There was no evidence of environmental enhancement of crack propagation in the stainless steel in clad specimens. The results indicate that the current approach of ignoring the cladding for assessment purposes is conservative at plant operating temperature.

  6. Synergistic Computational and Microstructural Design of Next- Generation High-Temperature Austenitic Stainless Steels

    SciTech Connect

    Karaman, Ibrahim; Arroyave, Raymundo

    2015-07-31

    The purpose of this project was to: 1) study deformation twinning, its evolution, thermal stability, and the contribution on mechanical response of the new advanced stainless steels, especially at elevated temperatures; 2) study alumina-scale formation on the surface, as an alternative for conventional chromium oxide, that shows better oxidation resistance, through alloy design; and 3) design new generation of high temperature stainless steels that form alumina scale and have thermally stable nano-twins. The work involved few baseline alloys for investigating the twin formation under tensile loading, thermal stability of these twins, and the role of deformation twins on the mechanical response of the alloys. These baseline alloys included Hadfield Steel (Fe-13Mn-1C), 316, 316L and 316N stainless steels. Another baseline alloy was studied for alumina-scale formation investigations. Hadfield steel showed twinning but undesired second phases formed at higher temperatures. 316N stainless steel did not show signs of deformation twinning. Conventional 316 stainless steel demonstrated extensive deformation twinning at room temperature. Investigations on this alloy, both in single crystalline and polycrystalline forms, showed that deformation twins evolve in a hierarchical manner, consisting of micron–sized bundles of nano-twins. The width of nano-twins stays almost constant as the extent of strain increases, but the width and number of the bundles increase with increasing strain. A systematic thermomechanical cycling study showed that the twins were stable at temperatures as high as 900°C, after the dislocations are annealed out. Using such cycles, volume fraction of the thermally stable deformation twins were increased up to 40% in 316 stainless steel. Using computational thermodynamics and kinetics calculations, we designed two generations of advanced austenitic stainless steels. In the first generation, Alloy 1, which had been proposed as an alumina

  7. Safety and environmental comparisons of stainless steel with alternative structural materials for fusion reactors

    SciTech Connect

    Kinzig, A.P.; Holdren, J.P.; Hibbard, P.J.

    1994-08-01

    Using the FuseDose II computer code, we calculated and compared several indices of safety and environmental (S&E) hazards for conceptual magnetic-fusion reactor designs based on a variety of structural materials-stainless steel, ferritic steel, vanadium-chromium-titanium alloy, and silicon-carbide-and, for comparison, the fuel of a liquid-metal fast breeder fission reactor. FuseDose II is a second-generation code derived from the Fuse-Dose code used in the U.S. Department of Energy`s Committee on Environmental, Safety, and Economic Aspects of Magnetic Fusion Energy (ESECOM) study in the late 1980s. The comparisons update and extend those of the ESECOM study by adding the stainless-steel case, some new indices, graphical representation of the results, and other refinements. The results of our analysis support earlier conclusions concerning the S&E liabilities of stainless steel: The use of stainless steel would significantly reduce the S&E advantages of fusion over fission that are implied by the indices we consider, compared with the advantages portrayed in the ESECOM results for lower-activation fusion materials. The dose potentials represented by the radioactive materials that conceivably could be mobilized in severe accidents are substantially higher for the stainless steel case than for the lower activation fusion designs analyzed by ESECOM, and the waste disposal burden imposed by a stainless steel fusion reactor, though significantly smaller than that associated with a fission reactor of the same output, is high enough to rule out the chance of qualification for shallow burial under current regulations (in contrast to some of the lower activation fusion cases). This work underscores the conclusion that research to demonstrate the viability of the low-activation materials is essential if fusion is to achieve its potential for large and easily demonstrated S&E advantages over fission. 37 refs., 17 figs., 8 tabs.

  8. Electrolytic etching process provides effective bonding surface on stainless steel

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Electrolytic etching process prepares surfaces of a stainless steel shell for reliable, high strength adhesive bonding to dielectric materials. The process uses a 25 percent aqueous solution of phosphoric acid.

  9. Stainless-steel elbows formed by spin forging

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Large seamless austenitic stainless steel elbows are fabricated by spin forging /rotary shear forming/. A specially designed spin forging tool for mounting on a hydrospin machine has been built for this purpose.

  10. 27. STAINLESS STEEL FERMENTING CASKS MADE BY ZERO MANG OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. STAINLESS STEEL FERMENTING CASKS MADE BY ZERO MANG OF WASHINGTON, MISSOURI. VIEW LOOKING NORTH TOWARD VAULT OF THE TWELVE APOSTLES - Stone Hill Winery, 401 West Twelfth Street, Hermann, Gasconade County, MO

  11. Stress corrosion cracking evaluation of precipitation-hardening stainless steel

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.; Nelson, E. E.

    1970-01-01

    Accelerated test program results show which precipitation hardening stainless steels are resistant to stress corrosion cracking. In certain cases stress corrosion susceptibility was found to be associated with the process procedure.

  12. Nafion coated stainless steel for anti-biofilm application.

    PubMed

    Zhong, Li Juan; Pang, Li Qing; Che, Li Ming; Wu, Xue E; Chen, Xiao Dong

    2013-11-01

    Biofilms can adhere to most surfaces and have caused a wide range of problems in various industrial processes as well as daily life activities. In this work, the anti-biofilm ability of Nafion-coated stainless steel surface was investigated and our results showed that stainless steel discs coated with 1% Nafion can significantly reduce E. coli adhesion. Nafion has a large amount of negatively charged sulphonate groups, and the findings of this study suggest that the negative surface charge can greatly reduce bacterial adhesion through increasing the electrostatic repulsion between negatively charged bacterial cells and Nafion coated stainless steel surface. The roughness of coated and uncoated stainless steel discs made no significant differences while the hydrophobic of the discs increased after coated with Nafion.

  13. Surface modified stainless steels for PEM fuel cell bipolar plates

    DOEpatents

    Brady, Michael P [Oak Ridge, TN; Wang, Heli [Littleton, CO; Turner, John A [Littleton, CO

    2007-07-24

    A nitridation treated stainless steel article (such as a bipolar plate for a proton exchange membrane fuel cell) having lower interfacial contact electrical resistance and better corrosion resistance than an untreated stainless steel article is disclosed. The treated stainless steel article has a surface layer including nitrogen-modified chromium-base oxide and precipitates of chromium nitride formed during nitridation wherein oxygen is present in the surface layer at a greater concentration than nitrogen. The surface layer may further include precipitates of titanium nitride and/or aluminum oxide. The surface layer in the treated article is chemically heterogeneous surface rather than a uniform or semi-uniform surface layer exclusively rich in chromium, titanium or aluminum. The precipitates of titanium nitride and/or aluminum oxide are formed by the nitriding treatment wherein titanium and/or aluminum in the stainless steel are segregated to the surface layer in forms that exhibit a low contact resistance and good corrosion resistance.

  14. Compressive Strength of Stainless-Steel Sandwiches at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Mathauser, Eldon E.; Pride, Richard A.

    1959-01-01

    Experimental results are presented from crippling tests of stainless-steel sandwich specimens in the temperature range from 80 F to 1,200 F. The specimens included resistance-welded 17-7 PH stainless-steel sandwiches with single-corrugated cores, type 301 stainless-steel sandwiches with double-corrugated cores, and brazed 17-7 PH stainless-steel sandwiches with honeycomb cores. The experimental strengths are compared with predicted buckling and crippling strengths. The crippling strengths were predicted from the calculated maximum strength of the individual plate elements of the sandwiches and from a correlation procedure which gives the elevated-temperature crippling strength when the experimental room-temperature crippling strengths are known. Photographs of some of the tested specimens are included to show the modes of failure.

  15. Cavitation erosion of duplex and super duplex stainless steels

    SciTech Connect

    Kwok, C.T.; Man, H.C.; Cheng, F.T.

    1998-10-05

    Owing to their excellent corrosion resistance, stainless steels are widely used both in the marine, urban water, chemical and food industries. In addition to the corrosive environment, high fluid flow speeds are always encountered for components used in these industries. The cavitation characteristics of S30400 and S31600 austenitic stainless steels and duplex stainless steels were studied in detail by a number of authors. It was generally agreed that S30400 has higher cavitation erosion resistance than that of S31600 due to higher tendency of strain induced martensitic transformation under high impulse of stress. A considerable number of results on stress corrosion cracking characteristics of SDSS and duplex stainless steels have been published but data concerning their cavitation erosion property are extremely rare.

  16. Ultrasonics permits brazing complex stainless steel assembly without flux

    NASA Technical Reports Server (NTRS)

    Baker, W. H.

    1967-01-01

    Ultrasonic vibration of an assembly of stainless steel instrumentation tubes ensures brazing without flux. Vibration with an ultrasonic transducer permits the brazing material to flow down each tube in contact with a seal plug installed in a pressure vessel wall.

  17. Eddy sensors for small diameter stainless steel tubes.

    SciTech Connect

    Skinner, Jack L.; Morales, Alfredo Martin; Grant, J. Brian; Korellis, Henry James; LaFord, Marianne Elizabeth; Van Blarigan, Benjamin; Andersen, Lisa E.

    2011-08-01

    The goal of this project was to develop non-destructive, minimally disruptive eddy sensors to inspect small diameter stainless steel metal tubes. Modifications to Sandia's Emphasis/EIGER code allowed for the modeling of eddy current bobbin sensors near or around 1/8-inch outer diameter stainless steel tubing. Modeling results indicated that an eddy sensor based on a single axial coil could effectively detect changes in the inner diameter of a stainless steel tubing. Based on the modeling results, sensor coils capable of detecting small changes in the inner diameter of a stainless steel tube were designed, built and tested. The observed sensor response agreed with the results of the modeling and with eddy sensor theory. A separate limited distribution SAND report is being issued demonstrating the application of this sensor.

  18. A mechanistic study of the effects of nitrogen on the corrosion properties of stainless steels

    SciTech Connect

    Levey, P.R.; Bennekom, A. van

    1995-12-01

    The effects of nitrogen alloying on the corrosion properties of stainless steels (SS) is a matter of debate. A number of apparently contradictory results have been presented by various researchers. The actual mechanism by which nitrogen alloying influences the corrosion properties of SS has been the topic of even more controversy. The effects of nitrogen on the corrosion and mechanical properties of SS were reviewed. Various proposals relating to the mechanistic effect of nitrogen alloying on the corrosion properties of SS were evaluated critically by comparing the various theories.

  19. The role of dislocation channeling in IASCC initiation of neutron irradiated austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Stephenson, Kale Jennings

    The objective of this study was to understand the role of dislocation channeling in the initiation of irradiation-assisted stress corrosion cracking (IASCC) of neutron irradiated austenitic stainless steel using a novel four-point bend test. Stainless steels used in this study were irradiated in the BOR-60 fast reactor at 320 °C, and included a commercial purity 304L stainless steel irradiated to 5.5, 10.2, and 47.5 dpa, and two high purity stainless steels, Fe-18Cr-12Ni and Fe-18Cr-25Ni, irradiated to ~10 dpa. The four-point bend test produced the same relative IASCC susceptibility as constant extension rate tensile (CERT) experiments performed on the same irradiated alloys in boiling water reactor normal water chemistry. The cracking susceptibility of the CP 304L alloy was high at all irradiation dose levels, enhanced by the presence of MnS inclusions in the alloy microstructure, which dissolve in the NWC environment. Dissolution of the MnS inclusion results in formation of an oxide cap that occludes the inclusion site, creating a crevice condition with a high propensity for crack initiation. Crack initiation at these locations was induced by stress concentration at the intersecting grain boundary, resulting from the intersection of a discontinuous dislocation channels (DC). Stress to initiate an IASCC crack decreased with dose due earlier DC initiation. The HP Fe-18Cr-12Ni alloy had low susceptibility to IASCC, while the high Ni alloy exhibited no cracking susceptibility. The difference in susceptibility among these conditions was attributed to the propensity for DCs to transmit across grain boundaries, which controls stress accumulation at DC -- grain boundary intersections.

  20. Is cell viability always directly related to corrosion resistance of stainless steels?

    PubMed

    Salahinejad, E; Ghaffari, M; Vashaee, D; Tayebi, L

    2016-05-01

    It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn-Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn-Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals.

  1. Fusion welding of advanced borated stainless steels. Final report: CRADA No. CR1042

    SciTech Connect

    Robino, C.V.; Cieslak, M.J.

    1994-02-01

    This work addressed two major areas concerning joining of advanced borated stainless steels. These areas included the development of a understanding of the physical metallurgy of borated stainless steels and the development of welding processes and post-weld heat treatments for these alloys. Differential thermal analysis experiments were conducted on ten heats of borated stainless steel to determine the transformation temperatures and melting behavior of the alloys. On-heating solidus temperatures were measured for all of the alloys and were used to define the temperatures associated with the fusion line during welding. Isothermal heat treatments designed to evaluate the effects of elevated temperature exposures on the toughness of the borated grades were conducted. These tests were used to determine if significant changes in the microstructure or mechanical properties of weld heat-affected zones (HAZ) occur. Specifically, the tests addressed the solid-state region of the HAZ. The test matrix included a variety of alloy compositions and thermal exposures at temperatures near the on-heating solidus (as determined by the DTA experiments). Welding experiments designed to assess the mechanical properties and microstructure of gas-tungsten arc and electron beam welds were conducted.

  2. Corrosion fatigue of surgical stainless steel in synthetic physiological solution.

    PubMed

    Cahoon, J R; Holte, R N

    1981-03-01

    Fatigue tests conducted both in air and synthetic physiological solution show that the fatigue strength of surgical stainless steel in synthetic physiological solution is about 10% lower than the strength in air for a given endurance level. It is proposed that surgical stainless steel which is normally passive in physiological solution suffers corrosion fatigue because of susceptibility to crevice corrosion which occurs at extrusions and intrusions (crevices) on the surface thereby shortening the crack initiation time and the fatigue life.

  3. Measurement of intergranular attack in stainless steel using ultrasonic energy

    DOEpatents

    Mott, Gerry; Attaar, Mustan; Rishel, Rick D.

    1989-08-08

    Ultrasonic test methods are used to measure the depth of intergranular attack (IGA) in a stainless steel specimen. The ultrasonic test methods include a pitch-catch surface wave technique and a through-wall pulse-echo technique. When used in combination, these techniques can establish the extent of IGA on both the front and back surfaces of a stainless steel specimen from measurements made on only one surface.

  4. Procedure for flaw detection in cast stainless steel

    DOEpatents

    Kupperman, David S.

    1988-01-01

    A method of ultrasonic flaw detection in cast stainless steel components incorporating the steps of determining the nature of the microstructure of the cast stainless steel at the site of the flaw detection measurements by ultrasonic elements independent of the component thickness at the site; choosing from a plurality of flaw detection techniques, one such technique appropriate to the nature of the microstructure as determined and detecting flaws by use of the chosen technique.

  5. Decomposition of energetic chemicals contaminated with iron or stainless steel.

    PubMed

    Chervin, Sima; Bodman, Glenn T; Barnhart, Richard W

    2006-03-17

    Contamination of chemicals or reaction mixtures with iron or stainless steel is likely to take place during chemical processing. If energetic and thermally unstable chemicals are involved in a manufacturing process, contamination with iron or stainless steel can impact the decomposition characteristics of these chemicals and, subsequently, the safety of the processes, and should be investigated. The goal of this project was to undertake a systematic approach to study the impact of iron or stainless steel contamination on the decomposition characteristics of different chemical classes. Differential scanning calorimetry (DSC) was used to study the decomposition reaction by testing each chemical pure, and in mixtures with iron and stainless steel. The following classes of energetic chemicals were investigated: nitrobenzenes, tetrazoles, hydrazines, hydroxylamines and oximes, sulfonic acid derivatives and monomers. The following non-energetic groups were investigated for contributing effects: halogens, hydroxyls, amines, amides, nitriles, sulfonic acid esters, carbonyl halides and salts of hydrochloric acid. Based on the results obtained, conclusions were drawn regarding the sensitivity of the decomposition reaction to contamination with iron and stainless steel for the chemical classes listed above. It was demonstrated that the most sensitive classes are hydrazines and hydroxylamines/oximes. Contamination of these chemicals with iron or stainless steel not only destabilizes them, leading to decomposition at significantly lower temperatures, but also sometimes causes increased severity of the decomposition. The sensitivity of nitrobenzenes to contamination with iron or stainless steel depended upon the presence of other contributing groups: the presence of such groups as acid chlorides or chlorine/fluorine significantly increased the effect of contamination on decomposition characteristics of nitrobenzenes. The decomposition of sulfonic acid derivatives and tetrazoles

  6. New alloys to conserve critical elements. [replacing chromium in steels

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.

    1978-01-01

    Previous studies and surveys on availability of domestic reserves have shown that chromium is a most critical element within the U.S. metal industry. More precisely, the bulk of chromium is consumed in the production of stainless steels, specifically Type 304 stainless steel (304SS) which contains 18% Cr. The present paper deals with means of reducing chromium in commercial stainless steels by substituting more abundant or less expensive elements with the intent of maintaining the properties of 304SS. The discussion focuses on some of the oxidation and corrosion properties of new substitute stainless steels with only 12% Cr, which represents a potential saving of 33% of the chromium consumed in the production of 304SS. The alloying elements substituted for Cr in 304SS are selected according to their potential for protective oxide formation during high-temperature oxidation; these are Al, Si, Ti, Y, and misch metal which is 99.7% rare-earth metals containing 50 to 55% cerium. Other alloying elements to impart corrosion resistance are Mn, Mo, and V.

  7. X-ray attenuation properties of stainless steel (u)

    SciTech Connect

    Wang, Lily L; Berry, Phillip C

    2009-01-01

    Stainless steel vessels are used to enclose solid materials for studying x-ray radiolysis that involves gas release from the materials. Commercially available stainless steel components are easily adapted to form a static or a dynamic condition to monitor the gas evolved from the solid materials during and after the x-ray irradiation. Experimental data published on the x-ray attenuation properties of stainless steel, however, are very scarce, especially over a wide range of x-ray energies. The objective of this work was to obtain experimental data that will be used to determine how a poly-energetic x-ray beam is attenuated by the stainless steel container wall. The data will also be used in conjunction with MCNP (Monte Carlos Nuclear Particle) modeling to develop an accurate method for determining energy absorbed in known solid samples contained in stainless steel vessels. In this study, experiments to measure the attenuation properties of stainless steel were performed for a range of bremsstrahlung x-ray beams with a maximum energy ranging from 150 keV to 10 MeV. Bremsstrahlung x-ray beams of these energies are commonly used in radiography of engineering and weapon components. The weapon surveillance community has a great interest in understanding how the x-rays in radiography affect short-term and long-term properties of weapon materials.

  8. Performance of ferritic stainless steels for automobile muffler corrosion

    SciTech Connect

    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 artificial 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.

  9. Corrosion properties of S-phase layers formed on medical grade austenitic stainless steel.

    PubMed

    Buhagiar, Joseph; Dong, Hanshan

    2012-02-01

    The corrosion properties of S-phase surface layers formed in AISI 316LVM (ASTM F138) and High-N (ASTM F1586) medical grade austenitic stainless steels by plasma surface alloying with nitrogen (at 430°C), carbon (at 500°C) and both carbon and nitrogen (at 430°C) has been investigated. The corrosion behaviour of the S-phase layers in Ringer's solutions was evaluated using potentiodynamic and immersion corrosion tests. The corrosion damage was evaluated using microscopy, hardness testing, inductive coupled plasma mass spectroscopy and X-ray diffraction. The experimental results have demonstrated that low-temperature nitriding, carburising and carbonitriding can improve the localised corrosion resistance of both industrial and medical grade austenitic stainless steels as long as the threshold sensitisation temperature is not reached. Carburising at 500°C has proved to be the best hardening treatment with the least effect on the corrosion resistance of the parent alloy.

  10. 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.

  11. Stress corrosion cracking of neutron irradiated type 304 stainless steels

    SciTech Connect

    Tsukada, Takashi; Miwa, Yukio; Nakajima, Hajime

    1995-12-31

    To study the effect of minor elements on the irradiation assisted stress corrosion cracking (IASCC), a high purity type 304L stainless steel and its heats doped minor elements, Si, P, S, C and Ti were irradiated at 513 K to 6.7 {times} 10{sup 24} n/m{sup 2} (E>1 MeV). After irradiation, susceptibility to the stress corrosion cracking (SCC) was evaluated by the slow strain rate tensile (SSRT) test in an oxygenated high purity water at 573 K, and the fracture surface of the specimens was examined by the scanning electron microscopy (SEM). The specimens showed high susceptibilities to SCC. Specimens without addition of C showed the intergranular type SCC (IGSCC), while C doped specimens generally failed by the transgranular type SCC (TGSCC). Addition of C into the hi purity alloy caused an enhancement of radiation hardening and a remarkable increase in maximum stress during SSRT test. Enrichment of Si changed specifically tensile properties after irradiation and decreased maximum stress and improved total elongation. Addition of S greatly enhanced the IASCC susceptibility and addition of P seemed to be beneficial for suppressing it. An effect of Ti was not prominent in the alloy with a high C concentration.

  12. Fabrication of stainless steel clad tubing. [gas pressure bonding

    NASA Technical Reports Server (NTRS)

    Kovach, C. W.

    1978-01-01

    The feasibility of producing stainless steel clad carbon steel tubing by a gas pressure bonding process was evaluated. Such a tube product could provide substantial chromium savings over monolithic stainless tubing in the event of a serious chromium shortage. The process consists of the initial assembly of three component tubesets from conventionally produced tubing, the formation of a strong metallurgical bond between the three components by gas pressure bonding, and conventional cold draw and anneal processing to final size. The quality of the tubes produced was excellent from the standpoint of bond strength, mechanical, and forming properties. The only significant quality problem encountered was carburization of the stainless clad by the carbon steel core which can be overcome by further refinement through at least three different approaches. The estimated cost of clad tubing produced by this process is greater than that for monolithic stainless tubing, but not so high as to make the process impractical as a chromium conservation method.

  13. Phonon dispersion in austenitic stainless steel Fe18Cr12Ni2Mo

    NASA Astrophysics Data System (ADS)

    Hoelzel, M.; Danilkin, S. A.; Hoser, A.; Ehrenberg, H.; Wieder, T.; Fuess, H.

    The phonon dispersion of Fe18Cr12Ni2Mo austenitic stainless steel was measured along the symmetry directions [001], [110] and [111]. Data were analysed in the frame of the Born-von Karman model of lattice dynamics. The obtained force constants were used to evaluate the elastic constants and the engineering elastic moduli. Our results for the elastic constants confirm empirical relationships between the elastic constants found for FCC FeCrNi alloys.

  14. Micro-electrospray with stainless steel emitters.

    PubMed

    Shui, Wenqing; Yu, Yanling; Xu, Xuejiao; Huang, Zhenyu; Xu, Guobing; Yang, Pengyuan

    2003-01-01

    The physical processes underlying micro-electrospray (micro-ES) performance were investigated using a stainless steel (SS) emitter with a blunt tip. Sheathless micro-ES could be generated at a blunt SS tip without any tapering or sanding if ESI conditions were optimized. The Taylor cone was found to shrink around the inner diameter of the SS tubing, which permitted a low flow rate of 150 nL/min for sheathless microspray on the blunt tip (100 microm i.d. x 400 microm o.d.). It is believed that the wettability and/or hydrophobicity of SS tips are responsible for their micro-ES performance. The outlet orifice was further nipped to reduce the size of the spray cone and limit the flow rate to 50-150 nL/min, resulting in peptide detection down to attomole quantities consumed per spectrum. The SS emitter was also integrated into a polymethylmethacrylate microchip and demonstrated satisfactory performance in the analysis and identification of a myoglobin digest.

  15. Weldable, age hardenable, austenitic stainless steel

    DOEpatents

    Brooks, J.A.; Krenzer, R.W.

    1975-07-22

    An age hardenable, austenitic stainless steel having superior weldability properties as well as resistance to degradation of properties in a hydrogen atmosphere is described. It has a composition of from about 24.0 to about 34.0 weight percent (w/o) nickel, from about 13.5 to about 16.0 w/o chromium, from about 1.9 to about 2.3 w/o titanium, from about 1.0 to about 1.5 w/ o molybdenum, from about 0.01 to about 0.05 w/o carbon, from about 0 to about 0.25 w/o manganese, from about 0 to about 0.01 w/o phosphorous and preferably about 0.005 w/o maximum, from about 0 to about 0.010 w/o sulfur and preferably about 0.005 w/o maximum, from about 0 to about 0.25 w/o silicon, from about 0.1 to about 0.35 w/o aluminum, from about 0.10 to about 0.50 w/o vanadium, from about 0 to about 0.0015 w/o boron, and the balance essentially iron. (auth)

  16. Corrosion of stainless steel during acetate production

    SciTech Connect

    Qi, J.S.; Lester, G.C.

    1996-07-01

    Corrosion of types 304, 304L, 316, and 316L stainless steel (SS) during the esterification of acetic acid and alcohol or glycol ether was investigated. The catalyst for this reaction, sulfuric acid or para-toluene sulfonic acid (PTSA), was shown to cause more corrosion on reactor equipment than CH{sub 3}COOH under the process conditions commonly practiced in industry. The corrosive action of the catalyst occurred only in the presence of water. Thus, for the batch processes, corrosion occurred mostly during the initial stage of esterification, where water produced by the reaction created an aqueous environment. After water was distilled off, the corrosion rate declined to a negligible value. The corrosion inhibitor copper sulfate, often used in industrial acetate processes, was found to work well for a low-temperature process (< 95 C) such as in production of butyl acetate, but it accelerated corrosion in the glycol ether acetate processes where temperatures were > 108 C. Process conditions that imparted low corrosion rates were determined.

  17. NanoComposite Stainless Steel Powder Technologies

    SciTech Connect

    DeHoff, R.; Glasgow, C.

    2012-07-25

    Oak Ridge National Laboratory has been investigating a new class of Fe-based amorphous material stemming from a DARPA, Defense Advanced Research Projects Agency initiative in structural amorphous metals. Further engineering of the original SAM materials such as chemistry modifications and manufacturing processes, has led to the development of a class of Fe based amorphous materials that upon processing, devitrify into a nearly homogeneous distribution of nano sized complex metal carbides and borides. The powder material is produced through the gas atomization process and subsequently utilized by several methods; laser fusing as a coating to existing components or bulk consolidated into new components through various powder metallurgy techniques (vacuum hot pressing, Dynaforge, and hot isostatic pressing). The unique fine scale distribution of microstructural features yields a material with high hardness and wear resistance compared to material produced through conventional processing techniques such as casting while maintaining adequate fracture toughness. Several compositions have been examined including those specifically designed for high hardness and wear resistance and a composition specifically tailored to devitrify into an austenitic matrix (similar to a stainless steel) which poses improved corrosion behavior.

  18. 75 FR 30434 - Stainless Steel Plate From Belgium, Italy, Korea, South Africa, and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-01

    ... COMMISSION [Investigation Nos. 701-TA-376 and 379 and 731-TA-788, 790-793 (Second Review)] Stainless Steel... steel plate from Belgium and South Africa and the antidumping duty orders on stainless steel plate from... determine whether revocation of the countervailing duty orders on stainless steel plate from Belgium...

  19. 78 FR 34644 - Stainless Steel Plate in Coils From Belgium: Preliminary Results of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ... International Trade Administration Stainless Steel Plate in Coils From Belgium: Preliminary Results of... administrative review of the antidumping duty order on stainless steel plate in coils (steel plate) from Belgium...: Scope of the Order The product covered by this order is certain stainless steel plate in...

  20. Preliminary Microstructural Characterization of Gadolinium-Enriched Stainless Steels for Spent Nuclear Fuel Baskets (title change from A)

    SciTech Connect

    DUPONT,J.N.; ROBINO,CHARLES V.; STEPHENS JR.,JOHN J.; MCCONNELL,PAUL E.; MIZIA,R.; BRANAGAN,D.

    2000-07-24

    Gadolinium (Gd) is a very potent neutron absorber that can potentially provide the nuclear criticality safety required for interim storage, transport, and final disposal of spent nuclear fuel. Gd could be incorporated into an alloy that can be fabricated into baskets to provide structural support, corrosion resistance, and nuclear criticality control. In particular, Gd alloyed with stainless steel has been identified as a material that may fulfill these functional requirements. However, no information is available in the open literature that describes the influence of Gd on the microstructure and resultant mechanical properties of stainless steels alloyed with Gd. Such information is vital for determination of the suitability of these types of alloys for the intended application. Characterization of Gd-stainless steel (Gd-SS) alloys is also necessary for an American Society for Testing and Materials (ASTM) material specification, subsequent code approval by the American Society of Mechanical Engineers (ASME), and regulatory approval by the Nuclear Regulatory Commission for subsequent use by the nuclear industry. The Department of Energy National Spent Nuclear Fuel Program at Idaho National Engineering and Environmental Laboratory has commissioned Lehigh University and Sandia National Laboratories to characterize the properties of a series of Gd-SS alloys to assess their suitability for the spent fuel basket application. Preliminary microstructural characterization results are presented on Gd stainless steels. Small gas tungsten arc buttons were prepared by melting 316L stainless steel with 0.1 to 10 wt.% Gd. These samples were characterized by light optical and electron optical microscopy to determine the distribution of alloying elements and volume fraction of Gd-rich phase. The results acquired to date indicate that no Gd is dissolved in the austenite matrix. Instead, the Gd was present as an interdendritic constituent, and the amount of the Gd-rich constituent

  1. Irradiation performance of 9--12 Cr ferritic/martensitic stainless steels and their potential for in-core application in LWRs

    SciTech Connect

    Jones, R.H.; Gelles, D.S.

    1993-08-01

    Ferritic-martensitic stainless steels exhibit radiation stability and stress corrosion resistance that make them attractive replacement materials for austenitic stainless steels for in-core applications. Recent radiation studies have demonstrated that 9% Cr ferritic/martensitic stainless steel had less than a 30C shift in ductile-to-brittle transition temperature (DBTT) following irradiation at 365C to a dose of 14 dpa. These steels also exhibit very low swelling rates, a result of the microstructural stability of these alloys during radiation. The 9 to 12% Cr alloys to also exhibit excellent corrosion and stress corrosion resistance in out-of-core applications. Demonstration of the applicability of ferritic/martensitic stainless steels for in-core LWR application will require verification of the irradiation assisted stress corrosion cracking behavior, measurement of DBTT following irradiation at 288C, and corrosion rates measurements for in-core water chemistry.

  2. From flint to stainless steel: observations on surgical instrument composition.

    PubMed Central

    Kirkup, J.

    1993-01-01

    Man's failure to extract deeply embedded thorns and arrowheads, with bare hands and teeth, stimulated 'instrument substitutes' mimicking these appendages. Evidence from primitive communities suggest animal, plant and mineral items were employed, both before and after metal became the standard material of today's armamentarium. Changing surgical instrument composition has mirrored concurrent technology and manufacturing methods both of which are reviewed. Particular significance is accorded flint, bronze, crucible steel, thermal sterilisation, nickel-plate, stainless steel and disposable plastics. The paper is based on an exhibition From Flint to Stainless Steel on display at the College. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:8215156

  3. Stainless steel tube-based cell cryopreservation containers.

    PubMed

    Shih, Wei-Hung; Yu, Zong-Yan; Wu, Wei-Te

    2013-12-01

    This study focused on increasing the freezing rate in cell vitrification cryopreservation by using a cryopreservation container possessing rigid mechanical properties and high heat-transfer efficiency. Applying a fast freezing rate in vitrification cryopreservation causes a rapid temperature change in the cryopreservation container and has a substantial impact on mechanical properties; therefore, a highly rigid cryopreservation container that possesses a fast freezing rate must be developed. To produce a highly rigid cryopreservation container possessing superior heat transfer efficiency, this study applies an electrochemical machining (ECM) method to an ANSI 316L stainless steel tube to treat the surface material by polishing and roughening, thereby increasing the freezing rate and reducing the probability of ice crystal formation. The results indicated that the ECM method provided high-quality surface treatment of the stainless steel tube. This method can reduce internal surface roughness in the stainless steel tube, thereby reducing the probability of ice crystal formation, and increase external surface roughness, consequently raising convection heat-transfer efficiency. In addition, by thinning the stainless steel tube, this method reduces heat capacity and thermal resistance, thereby increasing the freezing rate. The freezing rate (3399 ± 197 °C/min) of a stainless steel tube after interior and exterior polishing and exterior etching by applying ECM compared with the freezing rate (1818 ± 54 °C/min) of an original stainless steel tube was increased by 87%, which also exceeds the freezing rate (2015 ± 49 °C/min) of an original quartz tube that has a 20% lower heat capacity. However, the results indicated that increasing heat-transferring surface areas and reducing heat capacities cannot effectively increase the freezing rate of a stainless steel tube if only one method is applied; instead, both techniques must be implemented concurrently to improve the

  4. Promising in vitro performances of a new nickel-free stainless steel.

    PubMed

    Montanaro, Lucio; Cervellati, Marina; Campoccia, Davide; Arciola, Carla Renata

    2006-03-01

    Stainless steel is a metallic alloy largely employed in orthopaedics. However, the presence in its composition of a high quantity of nickel, an agent known to trigger toxic and allergic responses, is cause for concern. In this study, we have investigated the in vitro biocompatibility of a new nickel-reduced stainless steel, namely Böhler P558, in comparison to the conventional stainless steel AISI 316L. The neutral red (NR) uptake and the amido black (AB) tests were performed on L929 fibroblasts and MG63 osteoblasts to assess the cytotoxicity, while cytogenetic effects were evaluated on CHOK1 cells by studying the frequency of Sister Chromatid Exchanges (SCE) and chromosomal aberrations. Ames test was used to detect the mutagenic activity. The expression of selected markers typical of differentiated osteoblasts, such as alkaline phosphatase activity (ALP), type I collagen (CICP) and osteocalcin (OC) production, were also monitored in MG63 cells cultured on the tested materials. Our results indicate the absence of significant cytotoxicity and genotoxicity for both test alloys. ALP, CICP and OC analyses confirmed that both materials support the expression of these phenotypic markers. Overall, these data show that this Ni-free alloy possesses good in vitro biocompatibility and could have a potential for orthopaedic applications.

  5. Corrosion behavior of austenitic stainless steels in chloride containing ozone solutions

    SciTech Connect

    Pohjanne, P.

    1997-08-01

    Environmental concern about chlorinated organic compounds generated from traditional bleach plants has led to a development of new environmentally friendly bleaching processes. Recently, the development of ozone bleaching has progressed from pilot operations to production scale installations. Ozone is currently used as a bleaching agent of pulp as a replacement for chlorine based bleaching chemicals. Yet, there are few articles which are dealing with ozone and its effect to corrosion resistance of stainless steels or any other construction materials used in bleaching equipment. In this paper corrosion behavior of austenitic stainless steels, grades AISI 316, AISI 317LNM, UNS S31254 and UNS 32654 PM, were studied in simulated ozone bleaching environments. The laboratory tests showed that in ozone environments without chlorides the corrosion resistance of AISI 316 was superior to that of the high-alloyed stainless steels, due to the relatively low amount of alloying elements. The sequence was reversed in ozone environments containing chlorides. In the presence of chlorides AISI 316 was susceptible to localized corrosion whereas the high-alloyed UNS S31254 and UNS S 32654 PM were resistant to localized corrosion in all chloride concentrations examined.

  6. Stress Relaxation in Tensile Deformation of 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    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.

  7. Enhancement of Stainless Steel's Mechanical Properties via Carburizing Process

    NASA Astrophysics Data System (ADS)

    Ahmad, S.; Alias, S. K.; Abdullah, B.; Hafiz Mohd Bakri, Mohd.; Hafizuddin Jumadin, Muhammad; Mat Shah, Muhammad Amir

    2016-11-01

    Carburizing process is a method to disperse carbon into the steel surface in order to enhance its mechanical properties such as hardness and wear resistance. This paper study investigates the effect of carburizing temperature to the carbon dispersion layer in stainless steel. The standard AISI 304 stainless steel was carburized in two different temperatures which were 900°C and 950°C. The effect of carbon dispersion layers were observed and the results indicated that the increasing value of the average dispersion layer from 1.30 mm to 2.74 mm thickness was found to be related to increment of carburizing holding temperature . The increment of carbon thickness layer also resulted in improvement of hardness and tensile strength of carburized stainless steel.

  8. Machinability of a Stainless Steel by Electrochemical Discharge Microdrilling

    SciTech Connect

    Coteata, Margareta; Pop, Nicolae; Slatineanu, Laurentiu; Schulze, Hans-Peter; Besliu, Irina

    2011-05-04

    Due to the chemical elements included in their structure for ensuring an increased resistance to the environment action, the stainless steels are characterized by a low machinability when classical machining methods are applied. For this reason, sometimes non-traditional machining methods are applied, one of these being the electrochemical discharge machining. To obtain microholes and to evaluate the machinability by electrochemical discharge microdrilling, test pieces of stainless steel were used for experimental research. The electrolyte was an aqueous solution of sodium silicate with different densities. A complete factorial plan was designed to highlight the influence of some input variables on the sizes of the considered machinability indexes (electrode tool wear, material removal rate, depth of the machined hole). By mathematically processing of experimental data, empirical functions were established both for stainless steel and carbon steel. Graphical representations were used to obtain more suggestive vision concerning the influence exerted by the considered input variables on the size of the machinability indexes.

  9. Heat treatment temperature influence on ASTM A890 GR 6A super duplex stainless steel microstructure

    SciTech Connect

    Martins, Marcelo; E-mail: marcelo.martins@sulzer.com; Casteletti, Luiz Carlos

    2005-09-15

    Duplex and super duplex stainless steels are ferrous alloys with up to 26% chromium, 8% nickel, 5% molybdenum and 0.3% nitrogen, which are largely used in applications in media containing ions from the halogen family, mainly the chloride ion (Cl{sup -}). The emergence of this material aimed at substituting Copper-Nickel alloys (Cupro-Nickel) that despite presenting good corrosion resistance, has mechanical properties quite inferior to steel properties. The metallurgy of duplex and super duplex stainless steel is complex due to high sensitiveness to sigma phase precipitation that becomes apparent, due to the temperatures they are exposed on cooling from solidification as well as from heat treatment processes. The objective of this study was to verify the influence of heat treating temperatures on the microstructure and hardness of ASTM A890/A890M Gr 6A super duplex stainless steel type. Microstructure control is of extreme importance for castings, as the chemical composition and cooling during solidification inevitably provide conditions for precipitation of sigma phase. Higher hardness in these materials is directly associated to high sigma phase concentration in the microstructure, precipitated in the ferrite/austenite interface. While heat treatment temperature during solution treatment increases, the sigma phase content in the microstructure decreases and consequently, the material hardness diminishes. When the sigma phase was completely dissolved by the heat treatment, the material hardness was influenced only due to ferrite and austenite contents in the microstructure.

  10. Laser weldability of 21Cr-6Ni-9Mn stainless steel: Part II - Weldability diagrams

    SciTech Connect

    Tate, Stephen B.; Javernick, Daniel Anthony; Lienert, Thomas J.; Liu, Stephen

    2016-11-02

    In this second part of the study, weldability diagrams developed to relate solidification crack susceptibility and chemical composition for laser welded type 21Cr-6Ni-9Mn (21-6-9) stainless steel are presented. Sigmajig testing on 14 commercial 21-6-9 alloys, 20 experimental 21-6-9 alloys, and 7 other high-N, high-Mn austenitic stainless steels was used to develop weldability diagrams for solidification crack susceptibility for laser welding of type 21-6-9. Three travel speeds were used to show the changes in minimum Creq/Nieq for primary ferrite solidification as solidification rate increase d with travel speed . Primary austenite solidification was observed below 1.55 Creq/Nieq (Espy equivalents) at 21 mm/s travel speed. At 42 mm/s travel speed , a mix of solidification modes were displayed for alloys from 1.55-1.75 Creq/Nieq. Primary ferrite solidification was observed above 1.75 Creq/Nieq at both 42 and 85 mm/s travel speeds. No solidification cracking was observed for alloys with primary ferrite solidification. Lastly, variable cracking behavior was found in alloys with primary austenite solidification, but in general cracking was observed in alloys with greater than 0.02 wt-% combined impurity content according to (P+0.2S).

  11. Laser weldability of 21Cr-6Ni-9Mn stainless steel: Part II - Weldability diagrams

    DOE PAGES

    Tate, Stephen B.; Javernick, Daniel Anthony; Lienert, Thomas J.; ...

    2016-11-02

    In this second part of the study, weldability diagrams developed to relate solidification crack susceptibility and chemical composition for laser welded type 21Cr-6Ni-9Mn (21-6-9) stainless steel are presented. Sigmajig testing on 14 commercial 21-6-9 alloys, 20 experimental 21-6-9 alloys, and 7 other high-N, high-Mn austenitic stainless steels was used to develop weldability diagrams for solidification crack susceptibility for laser welding of type 21-6-9. Three travel speeds were used to show the changes in minimum Creq/Nieq for primary ferrite solidification as solidification rate increase d with travel speed . Primary austenite solidification was observed below 1.55 Creq/Nieq (Espy equivalents) at 21more » mm/s travel speed. At 42 mm/s travel speed , a mix of solidification modes were displayed for alloys from 1.55-1.75 Creq/Nieq. Primary ferrite solidification was observed above 1.75 Creq/Nieq at both 42 and 85 mm/s travel speeds. No solidification cracking was observed for alloys with primary ferrite solidification. Lastly, variable cracking behavior was found in alloys with primary austenite solidification, but in general cracking was observed in alloys with greater than 0.02 wt-% combined impurity content according to (P+0.2S).« less

  12. Crack initiation behavior of neutron irradiated model and commercial stainless steels in high temperature water

    NASA Astrophysics Data System (ADS)

    Stephenson, Kale J.; Was, Gary S.

    2014-01-01

    The objective of this study was to isolate key factors affecting the irradiation-assisted stress corrosion cracking (IASCC) susceptibility of eleven neutron-irradiated austenitic stainless steel alloys. Four commercial purity and seven high purity stainless steels were fabricated with specific changes in composition and microstructure, and irradiated in a fast reactor spectrum at 320 °C to doses between 4.4 and 47.5 dpa. Constant extension rate tensile (CERT) tests were performed in normal water chemistry (NWC), hydrogen water chemistry (HWC), or primary water (PW) environments to isolate the effects of environment, elemental solute addition, alloy purity, alloy heat, alloy type, cold work, and irradiation dose. The irradiated alloys showed a wide variation in IASCC susceptibility, as measured by the relative changes in mechanical properties and crack morphology. Cracking susceptibility measured by %IG was enhanced in oxidizing environments, although testing in the lowest potential environment caused an increase in surface crack density. Alloys containing solute addition of Ni or Ni + Cr exhibited no IASCC. Susceptibility was reduced in materials cold worked prior to irradiation, and increased with increasing irradiation dose. Irradiation-induced hardening was accounted for by the dislocation loop microstructure, however no relation between crack initiation and radiation hardening was found.

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

    SciTech Connect

    Prajitno, Djoko Hadi Syarif, Dani Gustaman

    2014-03-24

    The objective of this study is to evaluate high temperature oxidation behavior of austenitic stainless steel SS 304 in steam of nanofluids contain nanoparticle ZrO{sub 2}. The oxidation was performed at high temperatures ranging from 600 to 800°C. The oxidation time was 60 minutes. After oxidation the surface of the samples was analyzed by different methods including, optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). X-ray diffraction examination show that the oxide scale formed during oxidation of stainless steel AISI 304 alloys is dominated by iron oxide, Fe{sub 2}O{sub 3}. Minor element such as Cr{sub 2}O{sub 3} is also appeared in the diffraction pattern. Characterization by optical microscope showed that cross section microstructure of stainless steel changed after oxidized with the oxide scale on the surface stainless steels. SEM and x-ray diffraction examination show that the oxide of ZrO{sub 2} appeared on the surface of stainless steel. Kinetic rate of oxidation of austenite stainless steel AISI 304 showed that increasing oxidation temperature and time will increase oxidation rate.

  14. Mechanisms of Sticking Phenomenon Occurring during Hot Rolling of Two Ferritic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Son, Chang-Young; Kim, Chang Kyu; Ha, Dae Jin; Lee, Sunghak; Lee, Jong Seog; Kim, Kwang Tae; Lee, Yong Deuk

    2007-11-01

    Mechanisms of sticking phenomenon occurring during hot rolling of two ferritic stainless steels, STS 430J1L and STS 436L, were investigated in the present study. A hot-rolling simulation test was carried out using a high-temperature wear tester capable of controlling rolling speed, load, and temperature. The test results at 900 °C and 1000 °C revealed that the sticking process proceeded with three stages, i.e., nucleation, growth, and saturation, for the both stainless steels, and that STS 430J1L had a smaller number of sticking nucleation sites and slower growth rate than the STS 436L because of higher high-temperature hardness, thereby leading to less serious sticking. When the test was conducted at 1070 °C, the sticking hardly occurred in both stainless steels as Fe-Cr oxide layers were formed on the surface of the rolled materials. Thus, in order to prevent or minimize the sticking, it was suggested to improve high-temperature properties of stainless steels in the case of hot rolling at 900 °C to 1000 °C, and to establish appropriate rolling conditions and alloy compositions for ready formation of oxide layers in the case of hot rolling at higher temperatures than 1000 °C.

  15. 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 (H2O2) 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 H2O2 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.

  16. Effect of hydrogen on internal friction and Young`s modulus of Fe-Cr-Mn austenitic stainless steel

    SciTech Connect

    Usui, Makoto; Asano, Shigeru

    1996-06-01

    The internal friction technique has so far been applied to studies on hydrogen behavior in iron and steel. The hydrogen cold-work peak is well known for pure iron and has also been observed in BCC iron alloys such as ferritic stainless steel and maraging steel. It provides important information about the hydrogen- dislocation interaction in the BCC iron lattice. Meanwhile, for FCC iron alloys such as austenitic stainless steel, another characteristic hydrogen internal friction peak has been found by authors` group and confirmed by several other investigators. In the present study, type 205 austenitic stainless steel (Fe-17Cr-15Mn) was chosen as a nickel-free FCC iron alloy, in which manganese is totally substituted for nickel in type 304 steel. This steel has an unstable FCC lattice as is the case of type 304 steel, in which hydrogen-induced phase transformation depends on the austenite stability. However, the present steel was confirmed to form the {var_epsilon}{sub H} phase after cathodic hydrogen charging in a similar manner to the stable FCC lattice of type 310 steel. In addition, the Fe-Cr-Mn alloy shows a marked anomaly in the temperature dependence of Young`s modulus: an abrupt drop near the Neel temperature T{sub N} and successive lowering below T{sub N}, as has been reported in the literature for some antiferromagnetic materials. The effect of hydrogen on Young`s modulus was studied by several investigators, but there was great inconsistency among their experimental results. The purpose of this paper is to confirm the hydrogen peak of internal friction in type 205 steel and to examine the effect of hydrogen on Young`s modulus of this steel.

  17. Magnetic properties of stainless steels at room and cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Oxley, Paul; Goodell, Jennifer; Molt, Robert

    2009-07-01

    The magnetic properties of ten types of ferritic and martensitic stainless steels have been measured at room temperature and at 77 K. The steel samples studied were in the annealed state as received from the manufacturer. Our room temperature measurements indicate significantly harder magnetic properties than those quoted in the ASM International Handbook, which studied fully annealed stainless steel samples. Despite having harder magnetic properties than fully annealed steels some of the as-received steels still display soft magnetic properties adequate for magnetic applications. The carbon content of the steels was found to affect the permeability and coercive force, with lower-carbon steels displaying significantly higher permeability and lower coercive force. The decrease in coercive force with reduced carbon content is attributed to fewer carbide inclusions which inhibit domain wall motion. Cooling to 77 K resulted in harder magnetic properties. Averaged over the ten steels tested the maximum permeability decreased by 8%, the coercive force increased by 14%, and the residual and saturation flux densities increased by 4% and 3%, respectively. The change in coercive force when cooled is comparable to the theoretical prediction for iron, based on a model of domain wall motion inhibited by inclusions. The modest changes of the magnetic properties indicate that the stainless steels can still be used in magnetic applications at very low temperatures.

  18. Microstructural evolution in fast-neutron-irradiated austenitic stainless steels

    SciTech Connect

    Stoller, R.E.

    1987-12-01

    The present work has focused on the specific problem of fast-neutron-induced radiation damage to austenitic stainless steels. These steels are used as structural materials in current fast fission reactors and are proposed for use in future fusion reactors. Two primary components of the radiation damage are atomic displacements (in units of displacements per atom, or dpa) and the generation of helium by nuclear transmutation reactions. The radiation environment can be characterized by the ratio of helium to displacement production, the so-called He/dpa ratio. Radiation damage is evidenced microscopically by a complex microstructural evolution and macroscopically by density changes and altered mechanical properties. The purpose of this work was to provide additional understanding about mechanisms that determine microstructural evolution in current fast reactor environments and to identify the sensitivity of this evolution to changes in the He/dpa ratio. This latter sensitivity is of interest because the He/dpa ratio in a fusion reactor first wall will be about 30 times that in fast reactor fuel cladding. The approach followed in the present work was to use a combination of theoretical and experimental analysis. The experimental component of the work primarily involved the examination by transmission electron microscopy of specimens of a model austenitic alloy that had been irradiated in the Oak Ridge Research Reactor. A major aspect of the theoretical work was the development of a comprehensive model of microstructural evolution. This included explicit models for the evolution of the major extended defects observed in neutron irradiated steels: cavities, Frank faulted loops and the dislocation network. 340 refs., 95 figs., 18 tabs.

  19. Alloy dissolution in argon stirred steel

    NASA Astrophysics Data System (ADS)

    Webber, Darryl Scott

    Alloying is required for the production of all steel products from small castings to large beams. Addition of large quantities of bulk alloys can result in alloy segregation and inconsistent alloy recovery. The objective of this research was to better understand alloy dissolution in liquid steel especially as it relates to Missouri S&Ts' patented continuous steelmaking process. A 45-kilogram capacity ladle with a single porous plug was used to evaluate the effect of four experimental factors on alloy dissolution: alloy species, alloy size or form, argon flow rate, and furnace tap temperature. Four alloys were tested experimentally including Class I low carbon ferromanganese, nickel and tin (as a surrogate for low melting alloys) and Class II ferroniobium. The alloys ranged in size and form from granular to 30 mm diameter lumps. Experimental results were evaluated using a theoretically based numerical model for the steel shell period, alloy mixing (Class I) and alloy dissolution (Class II). A CFD model of the experimental ladle was used to understand steel motion in the ladle and to provide steel velocity magnitudes for the numerical steel shell model. Experiments and modeling confirmed that smaller sized alloys have shorter steel shell periods and homogenize faster than larger particles. Increasing the argon flow rate shortened mixing times and reduced the delay between alloy addition and the first appearance of alloy in the melt. In addition, for every five degree increase in steel bath temperature the steel shell period was shortened by approximately four percent. Class II ferroniobium alloy dissolution was an order of magnitude slower than Class I alloy mixing.

  20. Evaluation of Mn substitution for Ni in alumina-forming austenitic stainless steels

    SciTech Connect

    Yamamoto, Yukinori; Santella, Michael L; Liu, Chain T; Evans, Neal D; Maziasz, Philip J; Brady, Michael P

    2009-01-01

    There has been increasing interest in the substitution of low-cost Mn for Ni in austenitic stainless steels due to the rising price of Ni. This paper investigates the possibility of such a substitution approach for the recently developed alumina (Al{sub 2}O{sub 3})-forming austenitic (AFA) class of heat-resistant stainless steels. Computational thermodynamic tools were utilized to predict the alloy composition range to maintain an austenitic matrix microstructure when Mn is substituted for Ni in the presence of Al, which is a strong body-centered-cubic (BCC) phase stabilizer. Phase equilibria, oxidation behavior, and creep properties of Fe-(10-14)Cr-(5--15)Mn-(4-12)Ni-(2.5-3)Al-Cu-Nb-C-B (in weight percent) based alloys were studied. The alloys based on Fe-14Cr-2.5Al-(5-9)Mn-(10-12)Ni exhibited the best balance of oxidation and creep resistance, which represents approximately 50% reduction in Ni content compared to previously developed AFA alloys. These low-Ni, high-Mn AFA alloys formed protective Al{sub 2}O{sub 3} scales up to 973-1073 K in air and at 923 K in air with 10% water vapor. Creep-rupture lives of the alloys under a severe screening condition of 1023 K and 100 MPa were in the 7.2 x 10{sup 5}-1.8 x 10{sup 6} s (200-500 h) range, which is comparable to or somewhat improved over that of type 347 stainless steel (Fe-18Cr-11Ni base).

  1. [Restoration of composite on etched stainless steel crowns. (1)].

    PubMed

    Goto, G; Zang, Y; Hosoya, Y

    1990-01-01

    Object of investigation The retention of composite resin to etched stainless steel crowns was tested as a possible method for restoring primary anterior teeth. Method employed 1) SEM observation Stainless steel crowns (Sankin Manufacture Co.) were etched with an aqua resia to create surface roughness and undercut to retain the composite resin to the crowns. Etching times were 1, 2, 3, 5, 8, 10 and 20 minutes, then washed in a 70% alcohol solution using an ultrasonic washer and dried. A total of 96 etched samples and non etched control samples were observed through the scanning electron microscope (Hitachi 520). 2) Shear bond strength test Stainless steel crowns were etched in an aqua resia from 1 to 20 minutes, then washed and dried. Composite resin (Photo Clearfil A, Kuraray Co.) with the bonding agent was placed on the crowns and the shear bond strength was tested in 56 samples using an Autograph (DCS-500, Shimazu). Results 1) SEM observation showed that the etching surface of stainless steel crowns created surface roughness and undercut. The most desirable surface was obtained in the 3 to 5 minute etching time specimens. 2) The highest bond strength was obtained in a 3 minute etching specimen. It was 42.12 MPa, although 29.26 MPa in mean value. Conclusion Etching with an aqua resia increased the adherence of composite resin to the surface of stainless steel crowns.

  2. Work of adhesion of dairy products on stainless steel surface

    PubMed Central

    Bernardes, Patrícia Campos; Araújo, Emiliane Andrade; dos Santos Pires, Ana Clarissa; Queiroz Fialho Júnior, José Felício; Lelis, Carini Aparecida; de Andrade, Nélio José

    2012-01-01

    The adhesion of the solids presents in food can difficult the process of surface cleaning and promotes the bacterial adhesion process and can trigger health problems. In our study, we used UHT whole milk, chocolate based milk and infant formula to evaluate the adhesion of Enterobacter sakazakii on stainless steel coupons, and we determine the work of adhesion by measuring the contact angle as well as measured the interfacial tension of the samples. In addition we evaluated the hydrophobicity of stainless steel after pre-conditioning with milk samples mentioned. E. sakazakii was able to adhere to stainless steel in large numbers in the presence of dairy products. The chocolate based milk obtained the lower contact angle with stainless steel surface, higher interfacial tension and consequently higher adhesion work. It was verified a tendency of decreasing the interfacial tension as a function of the increasing of protein content. The preconditioning of the stainless steel coupons with milk samples changed the hydrophobic characteristics of the surfaces and became them hydrophilic. Therefore, variations in the composition of the milk products affect parameters important that can influence the procedure of hygiene in surface used in food industry. PMID:24031951

  3. Aging of cast duplex stainless steels in LWR systems

    SciTech Connect

    Chopra, O.K.; Chung, H.M.

    1984-10-01

    A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. The existing data are evaluated to determine the expected embrittlement of cast components during the operating lifetime of reactors and to define the objectives and scope of the investigation. This presentation describes the status of the program. Data for the metallurgical characterization of the various cast stainless steels used in the investigation are presented. Charpy impact tests on short-term aged material indicate that CF-3 stainless steels are less susceptible to embrittlement than CF-8 or CF-8M stainless steels. Microstructural characterization of cast stainless steels that were obtained from Georg Fischer Co. and aged for up to 70,000 h at 300, 350, and 400/sup 0/C reveals the formation of four different types of precipitates that are not ..cap alpha..'. Embrittlement of the ferrite phase is primarily due to pinning of the dislocations by two of these precipitates, designated as Type M and Type X. The ferrite phase is embrittled after approx. 8 y at 300/sup 0/C and shows cleavage fracture. Examination of the fracture surfaces of the impact-test specimens indicates that the toughness of the long-term aged material is determined by the austenite phase. 8 figures, 3 tables.

  4. Antibacterial effect of silver nanofilm modified stainless steel surface

    NASA Astrophysics Data System (ADS)

    Fang, F.; Kennedy, J.; Dhillon, M.; Flint, S.

    2015-03-01

    Bacteria can attach to stainless steel surfaces, resulting in the colonization of the surface known as biofilms. The release of bacteria from biofilms can cause contamination of food such as dairy products in manufacturing plants. This study aimed to modify stainless steel surfaces with silver nanofilms and to examine the antibacterial effectiveness of the modified surface. Ion implantation was applied to produce silver nanofilms on stainless steel surfaces. 35 keV Ag ions were implanted with various fluences of 1 × 1015 to 1 × 1017 ions•cm-2 at room temperature. Representative atomic force microscopy characterizations of the modified stainless steel are presented. Rutherford backscattering spectrometry spectra revealed the implanted atoms were located in the near-surface region. Both unmodified and modified stainless steel coupons were then exposed to two types of bacteria, Pseudomonas fluorescens and Streptococcus thermophilus, to determine the effect of the surface modification on bacterial attachment and biofilm development. The silver modified coupon surface fluoresced red over most of the surface area implying that most bacteria on coupon surface were dead. This study indicates that the silver nanofilm fabricated by the ion implantation method is a promising way of reducing the attachment of bacteria and delay biofilm formation.

  5. Clean cast steel technology. Determination of transformation diagrams for duplex stainless steel

    SciTech Connect

    Chumbley, S. L.

    2005-09-01

    Duplex stainless steels (DSS) constitute both ferrite and austenite as a matrix. Such a microstructure confers a high corrosion resistance with favorable mechanical properties. However, intermetallic phases such as sigma ( can also form during casting or high-temperature processing and can degrade the properties of the DSS. This research was initiated to develop time-temperature-transformation (TTT) and continuous-cooling- transformation (CCT) diagrams of two types of cast duplex stainless steels, CD3MN (Fe 22Cr-5Ni-Mo-N) and CD3MWCuN (Fe-25Cr-7Ni-Mo-W-Cu-N), in order to understand the time and temperature ranges for intermetallic phase formation. The alloys were heat treated isothermally or under controlled cooling conditions and then characterized using conventional metallographic methods that included tint etching, and also using electron microscopy (SEM, TEM) and wavelength dispersive spectroscopy (WDS). The kinetics of intermetallic-phase ( formation were analyzed using the Johnson-Mehl-Avrami (JMA) equation in the case of isothermal transformations and a modified form of this equation in the case of continuous cooling transformations, The rate of intermetallic-phase formation was found to be much faster in CD3MWCuN than CD3MN due mainly to differences in the major alloying contents such as Cr, Ni and Mo. To examine in more detail the effects of these elements of the phase stabilities, a series of eight steel castings was designed with the Cr, Ni and Mo contents systematically varied with respect to the nominal composition of CD3MN. The effects of varying the contents of alloying additions on the formation of intermetallic phases were also studied computationally using the commercial thermodynamic software package, Thermo-Calc. In general, was stabilized with increasing Cr addition and by increasing Mo addition. However, a delicate balance among Ni and other minor elements such as N and Si also exists. Phase equilibria in DSS can be affected by local

  6. High strength bonding of titanium to stainless steel using an Ag interlayer

    NASA Astrophysics Data System (ADS)

    Lee, Jung G.; Hong, S. J.; Lee, M. K.; Rhee, C. K.

    2009-12-01

    Strong bonding between titanium (Ti) and stainless steel (STS) was achieved by employing a commercially available Ag-28Cu (wt.%) filler, and more importantly with a help of an Ag interlayer. A mass transport of the Ti elements from the substrate into the molten filler was completely prevented through the use of the Ag interlayer, so the resultant brazed joint was free from any brittle Ti-based intermetallic compounds. Notably, this Ti-STS dissimilar joint displayed a remarkable improvement in its bonding strength, demonstrating the potential application of an Ag interlayer for joining Ti and its alloys to various structural steels.

  7. 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.

  8. Stainless-Steel-Foam Structures Evaluated for Fan and Rotor Blades

    NASA Technical Reports Server (NTRS)

    Lerch, Bradley A.; Raj, Sai V.; Ghosn, Louis J.; Hebsur, Mohan G.; Cosgriff, Laura M.; Min, James B.; Holland, Frederic A., Jr.

    2005-01-01

    The goal of this project is to use a sandwich structure design, consisting of two stainlesssteel face sheets and a stainless-steel-foam core, to fabricate engine fan and propeller blades. Current fan blades are constructed either of polymer matrix composites (PMCs) or hollow titanium alloys. The PMC blades are expensive and have poor impact resistance on their leading edges, thereby requiring a metallic leading edge to satisfy the Federal Aviation Administration s impact requirements relating to bird strikes. Hollow titanium blades cost more to fabricate because of the intrinsically difficult fabrication issues associated with titanium alloys. However, both these current concepts produce acceptable lightweight fan blades.

  9. Improved Accident Tolerance of Austenitic Stainless Steel Cladding through Colossal Supersaturation with Interstitial Solutes

    SciTech Connect

    Ernst, Frank

    2016-10-13

    We proposed a program-supporting research project in the area of fuel-cycle R&D, specifically on the topic of advanced fuels. Our goal was to investigate whether SECIS (surface engineering by concentrated interstitial solute – carbon, nitrogen) can improve the properties of austenitic stainless steels and related structural alloys such that they can be used for nuclear fuel cladding in LWRs (light-water reactors) and significantly excel currently used alloys with regard to performance, safety, service life, and accident tolerance.

  10. DETECTION OF BACTERIAL BIOFILM ON STAINLESS STEEL BY HYPERSPECTRAL FLUORESCENCE IMAGING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, hyperspectral fluorescence imaging techniques were investigated for detection of microbial biofilm on stainless steel plates typically used to manufacture food processing equipment. Stainless steel coupons were immersed in bacterium cultures consisting of nonpathogenic E. coli, Pseudo...

  11. Evaluation of Direct Diode Laser Deposited Stainless Steel 316L on 4340 Steel Substrate for Aircraft Landing Gear Application

    DTIC Science & Technology

    2010-03-01

    AFRL-RX-WP-TP-2010-4149 EVALUATION OF DIRECT DIODE LASER DEPOSITED STAINLESS STEEL 316L ON 4340 STEEL SUBSTRATE FOR AIRCRAFT LANDING GEAR...March 2010 – 01 March 2010 4. TITLE AND SUBTITLE EVALUATION OF DIRECT DIODE LASER DEPOSITED STAINLESS STEEL 316L ON 4340 STEEL SUBSTRATE FOR...Code) N/A Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39-18 Evaluation of Direct Diode Laser Deposited Stainless Steel 316L on

  12. Wastewater minimization at a stainless steel manufacturing facility

    SciTech Connect

    Hayward-Browne, A.; Ackroyd, D.S.; Dave, B.B.

    1996-08-01

    As the environmental regulations associated with discharging water from industrial installations become increasingly more stringent and water in some areas becomes more scarce, water costs, both for purchase and disposal, become increasingly more expensive. So the importance of reusing and recycling water is heightened. This paper investigates the desire of a stainless steel manufacturing plant to improve the final product surface quality. Simple upgrading of the once-through rinsing process would have presented operational problems for the on-site effluent treatment plant and exceeded site discharge limits. A more innovative approach was sought. Explained are the stages taken to audit the plant, the initial work in proposing water recycle options and a computer modeling methodology for predicting water chemistry and economics. In conclusion, the stainless steel manufacturer discusses the implementation of the recycle project. Not only are the operational demands met, but the recycle option actually provides a return on investment to the stainless steel manufacturer rather than an additional cost.

  13. Guided growth by a stainless-steel tubular plate.

    PubMed

    Lin, Tung-Yi; Kao, Hsuan-Kai; Li, Wei-Chun; Yang, Wen-E; Chang, Chia-Hsieh

    2013-07-01

    Guided growth using titanium tension band plates is an advancement in the correction of angular deformity. We applied two-hole stainless-steel one-third tubular plates for the same purpose. There were 14 deformities around the knees in eight children, mean age 10.8 years at operation. The success rate was 92.9% (13/14). The average correction rate per month was 0.59° in the femur and 0.65° in the tibia. No premature physeal arrest, overcorrection, or rebound phenomenon was observed. A stainless-steel plate is a safe and effective option for guided growth surgery in countries where only stainless-steel plates are available.

  14. Evaluation of Additive Manufacturing for Stainless Steel Components

    SciTech Connect

    Peter, William H.; Lou, Xiaoyuan; List, III, Frederick Alyious; Webber, David

    2016-09-01

    This collaboration between Oak Ridge National Laboratory and General Electric Company aimed to evaluate the mechanical properties, microstructure, and porosity of the additively manufactured 316L stainless steel by ORNL’s Renishaw AM250 machine for nuclear application. The program also evaluated the stress corrosion cracking and corrosion fatigue crack growth rate of the same material in high temperature water environments. Results show the properties of this material to be similar to the properties of 316L stainless steel fabricated additively with equipment from other manufacturers with slightly higher porosity. The stress corrosion crack growth rate is similar to that for wrought 316L stainless steel for an oxygenated high temperature water environment and slightly higher for a hydrogenated high temperature water environment. Optimized heat treatment of this material is expected to improve performance in high temperature water environments.

  15. 76 FR 50495 - Stainless Steel Plate From Belgium, Italy, Korea, South Africa, and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-15

    ... COMMISSION Stainless Steel Plate From Belgium, Italy, Korea, South Africa, and Taiwan Determinations On the.... 1675(c)), that revocation of the countervailing duty order on stainless steel plate from South Africa and revocation of the antidumping duty orders on stainless steel plate from Belgium, Korea,...

  16. 75 FR 32503 - Stainless Steel Wire Rod From Italy, Japan, Korea, Spain, and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-08

    ... COMMISSION Stainless Steel Wire Rod From Italy, Japan, Korea, Spain, and Taiwan Determinations On the basis...)), that revocation of the antidumping duty orders on stainless steel wire rod from Italy, Japan, Korea... contained in USITC Publication 4154 (May 2010), entitled Stainless Steel Wire Rod from Italy, Japan,...

  17. 77 FR 27815 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-11

    ... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water AGENCY..., ``Aging Management of Stainless Steel Structures and Components in Treated Borated Water.'' This LR-ISG... stainless steel structures and components exposed to treated borated water. The NRC published Revision 2...

  18. 77 FR 39735 - Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-05

    ...)] Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines Determination On the basis...)), that revocation of the antidumping duty orders on stainless steel butt-weld pipe fittings From Italy... the Commission are contained in USITC Publication 4337 (June 2012), entitled Stainless Steel...

  19. 75 FR 53714 - Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-01

    ... 564 (Third Review)] Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan AGENCY... antidumping duty orders on stainless steel butt-weld pipe fittings from Japan, Korea, and Taiwan. SUMMARY: The... stainless steel butt-weld pipe fittings from Japan, Korea, and Taiwan would be likely to lead...

  20. 76 FR 69292 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-08

    ... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water AGENCY... Staff Guidance (LR-ISG), LR- ISG-2011-01, ``Aging Management of Stainless Steel Structures and... Learned (GALL) Report for the aging management of stainless steel structures and components exposed...

  1. 77 FR 3231 - Certain Stainless Steel Wire Rods From India: Continuation of Antidumping Duty Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-23

    ... Stainless Steel Wire Rods From India: Continuation of Antidumping Duty Order AGENCY: Import Administration... antidumping duty order on certain stainless steel wire rods from India would likely lead to continuation or... reviews of the antidumping duty order on certain stainless steel wire rods (``wire rods'') from...

  2. 75 FR 30437 - Stainless Steel Sheet and Strip From Germany, Italy, Japan, Korea, Mexico, and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-01

    ... COMMISSION Stainless Steel Sheet and Strip From Germany, Italy, Japan, Korea, Mexico, and Taiwan AGENCY... countervailing duty order on stainless steel sheet and strip from Korea and the antidumping duty orders on stainless steel sheet and strip from Germany, Italy, Japan, Korea, Mexico, and Taiwan. SUMMARY:...

  3. 75 FR 59744 - Stainless Steel Plate From Belgium, Italy, Korea, South Africa, and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-28

    ... COMMISSION [Investigation Nos. 701-TA-376 and 379 and 731-TA-788, 790-793 (Second Review)] Stainless Steel... countervailing duty orders on stainless steel plate from Belgium and South Africa and the antidumping duty orders on stainless steel plate from Belgium, Italy, Korea, South Africa, and Taiwan. SUMMARY:...

  4. 75 FR 59744 - Stainless Steel Sheet and Strip From Germany, Italy, Japan, Korea, Mexico, and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-28

    ... COMMISSION Stainless Steel Sheet and Strip From Germany, Italy, Japan, Korea, Mexico, and Taiwan AGENCY... five-year reviews concerning the countervailing duty order on stainless steel sheet and strip from Korea and the antidumping duty orders on stainless steel sheet and strip from Germany, Italy,...

  5. 77 FR 60673 - Drawn Stainless Steel Sinks From the People's Republic of China: Antidumping Duty Investigation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-04

    ... International Trade Administration Drawn Stainless Steel Sinks From the People's Republic of China: Antidumping...'') preliminarily determines that drawn stainless steel sinks (``drawn sinks'') from the People's Republic of China... unfinished, regardless of type of finish, gauge, or grade of stainless steel. Mounting clips,...

  6. 76 FR 49726 - Continuation of Antidumping and Countervailing Duty Orders: Stainless Steel Sheet and Strip in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-11

    ... International Trade Administration Continuation of Antidumping and Countervailing Duty Orders: Stainless Steel... stainless steel sheet and strip in coils from Japan, Korea, and Taiwan would likely lead to continuation or recurrence of dumping, that revocation of the countervailing duty (``CVD'') order on stainless steel...

  7. 75 FR 64709 - Stainless Steel Plate in Coils From Belgium: Notice of Rescission of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-20

    ... International Trade Administration Stainless Steel Plate in Coils From Belgium: Notice of Rescission of... ``Opportunity to Request Administrative Review'' of the antidumping duty order on stainless steel plate in coils... of an administrative review of the antidumping duty order on stainless steel plate in coils...

  8. 76 FR 31588 - Stainless Steel Plate in Coils From Belgium: Rescission of Countervailing Duty Administrative Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-01

    ... International Trade Administration Stainless Steel Plate in Coils From Belgium: Rescission of Countervailing... countervailing duty (``CVD'') order on stainless steel plate in coils from Belgium. See Antidumping or... initiating an administrative review of the CVD order on stainless steel plate in coils from Belgium...

  9. 77 FR 39467 - Stainless Steel Bar From India: Final Results of the Antidumping Duty Administrative Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-03

    ... International Trade Administration Stainless Steel Bar From India: Final Results of the Antidumping Duty... the administrative review of the antidumping duty order on stainless steel bar from India. The review..., 2012, the Department published Stainless Steel Bar From India: Preliminary Results and...

  10. 78 FR 7395 - Stainless Steel Bar From India: Preliminary Results of Antidumping Duty Administrative Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-01

    ... International Trade Administration Stainless Steel Bar From India: Preliminary Results of Antidumping Duty... the antidumping duty order on stainless steel bar (SSB) from India. The period of review (POR) is... Review: Stainless Steel Bar from India'' dated concurrently with this notice (``Preliminary...

  11. 77 FR 18211 - Drawn Stainless Steel Sinks From the People's Republic of China: Initiation of Countervailing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-27

    ... International Trade Administration Drawn Stainless Steel Sinks From the People's Republic of China: Initiation...'') petition concerning imports of drawn stainless steel sinks from the People's Republic of China (``PRC... Antidumping and Countervailing Duties Against Drawn Stainless Steel Sinks from the People's Republic of...

  12. 78 FR 13019 - Drawn Stainless Steel Sinks From the People's Republic of China: Investigation, Final Determination

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-26

    ... International Trade Administration Drawn Stainless Steel Sinks From the People's Republic of China... Drawn Stainless Steel Sinks From the People's Republic of China: Antidumping Duty Investigation, 77 FR... Co., Ltd. in the Investigation of Drawn Stainless Steel Sinks from the People's Republic of...

  13. 76 FR 18518 - Stainless Steel Sheet and Strip in Coils From Mexico: Rescission of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-04

    ... International Trade Administration Stainless Steel Sheet and Strip in Coils From Mexico: Rescission of... stainless steel sheet and strip in coils from Mexico. The period of review is July 1, 2009, through June 30... American Stainless, and AK Steel Corporation (collectively ``petitioners''), we are now rescinding...

  14. 76 FR 54207 - Stainless Steel Plate in Coils From Italy: Revocation of Antidumping Duty Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-31

    ... International Trade Administration Stainless Steel Plate in Coils From Italy: Revocation of Antidumping Duty... antidumping duty order on stainless steel plate in coils (SSPC) from Italy. See Initiation of Five-Year... in the United States within a reasonably foreseeable time. See Stainless Steel Plate From...

  15. 76 FR 31585 - Forged Stainless Steel Flanges From India: Notice of Rescission of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-01

    ... International Trade Administration Forged Stainless Steel Flanges From India: Notice of Rescission of... stainless steel flanges from India. The period of review is February 1, 2010, through January 22, 2011... stainless steel flanges from India. See Antidumping or Countervailing Duty Order, Finding, or...

  16. 75 FR 39663 - Stainless Steel Bar From Brazil: Final Results of Antidumping Duty Administrative Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-12

    ... International Trade Administration Stainless Steel Bar From Brazil: Final Results of Antidumping Duty... of its administrative review of the antidumping duty order on certain stainless steel bar from Brazil... results of its administrative review of the antidumping duty order on certain stainless steel bar...

  17. 75 FR 67689 - Stainless Steel Bar From Brazil: Preliminary Results of Antidumping Duty Administrative Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-03

    ... International Trade Administration Stainless Steel Bar From Brazil: Preliminary Results of Antidumping Duty... antidumping duty order on certain stainless steel bar from Brazil. The review covers one producer/ exporter of... Department published in the Federal Register an antidumping duty order on certain stainless steel bar...

  18. 78 FR 4383 - Stainless Steel Bar From Brazil: Preliminary Results of Antidumping Duty Administrative Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-22

    ... International Trade Administration Stainless Steel Bar From Brazil: Preliminary Results of Antidumping Duty... the antidumping duty order on stainless steel bar (SSB) from Brazil. The period of review (POR) is... Antidumping Duty Administrative Review: Stainless Steel Bar from Brazil'' dated concurrently with this...

  19. 76 FR 76437 - Certain Welded Stainless Steel Pipe From Korea and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-07

    ... COMMISSION Certain Welded Stainless Steel Pipe From Korea and Taiwan Determination On the basis of the record... revocation of the antidumping duty orders on certain welded stainless steel pipe from Korea and Taiwan would... Publication 4280 (December 2011), entitled Certain Welded Stainless Steel Pipe from Korea and...

  20. 76 FR 28809 - Stainless Steel Plate From Belgium; Termination of Five-Year Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-18

    ... COMMISSION Stainless Steel Plate From Belgium; Termination of Five-Year Review AGENCY: United States... review concerning the countervailing duty order on stainless steel plate from Belgium (75 FR 30777 and 75... its full five-year review of the countervailing duty order concerning stainless steel plate...

  1. 49 CFR 178.47 - Specification 4DS welded stainless steel cylinders for aircraft use.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Specification 4DS welded stainless steel cylinders...) SPECIFICATIONS FOR PACKAGINGS Specifications for Cylinders § 178.47 Specification 4DS welded stainless steel... stainless steel sphere (two seamless hemispheres) or circumferentially welded cylinder both with a...

  2. 78 FR 45271 - Welded Stainless Steel Pressure Pipe From Malaysia, Thailand, and Vietnam

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-26

    ... COMMISSION Welded Stainless Steel Pressure Pipe From Malaysia, Thailand, and Vietnam Determination On the... injured by reason of imports from Malaysia, Thailand, and Vietnam of welded stainless steel pressure pipe... injured or threatened with material injury by reason of LTFV imports of welded stainless steel...

  3. 49 CFR 178.47 - Specification 4DS welded stainless steel cylinders for aircraft use.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Specification 4DS welded stainless steel cylinders...) SPECIFICATIONS FOR PACKAGINGS Specifications for Cylinders § 178.47 Specification 4DS welded stainless steel... stainless steel sphere (two seamless hemispheres) or circumferentially welded cylinder both with a...

  4. 76 FR 46323 - Stainless Steel Sheet and Strip From Germany, Italy, Japan, Korea, Mexico, and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-02

    ... COMMISSION Stainless Steel Sheet and Strip From Germany, Italy, Japan, Korea, Mexico, and Taiwan... U.S.C.1675(c)), that revocation of the antidumping duty orders on stainless steel sheet and strip... revocation of the countervailing duty order on stainless steel sheet and strip from Korea and revocation...

  5. 49 CFR 178.47 - Specification 4DS welded stainless steel cylinders for aircraft use.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Specification 4DS welded stainless steel cylinders...) SPECIFICATIONS FOR PACKAGINGS Specifications for Cylinders § 178.47 Specification 4DS welded stainless steel... stainless steel sphere (two seamless hemispheres) or circumferentially welded cylinder both with a...

  6. 75 FR 67110 - Forged Stainless Steel Flanges From India and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-01

    ... COMMISSION Forged Stainless Steel Flanges From India and Taiwan AGENCY: United States International Trade... stainless steel flanges from India and Taiwan. SUMMARY: The Commission hereby gives notice that it has... determine whether revocation of the antidumping duty orders on forged stainless steel flanges from India...

  7. 49 CFR 178.47 - Specification 4DS welded stainless steel cylinders for aircraft use.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Specification 4DS welded stainless steel cylinders...) SPECIFICATIONS FOR PACKAGINGS Specifications for Cylinders § 178.47 Specification 4DS welded stainless steel... stainless steel sphere (two seamless hemispheres) or circumferentially welded cylinder both with a...

  8. 77 FR 45653 - Stainless Steel Bar From Brazil, India, Japan, and Spain; Determination

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-01

    ... (Third Review)] Stainless Steel Bar From Brazil, India, Japan, and Spain; Determination Determination On... U.S.C. 1675(c)), that revocation of the antidumping duty orders on stainless steel bar from Brazil... (July 2012), entitled Stainless Steel Bar from Brazil, India, Japan, and Spain: Investigation Nos....

  9. 77 FR 60478 - Control of Ferrite Content in Stainless Steel Weld Metal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-03

    ... COMMISSION Control of Ferrite Content in Stainless Steel Weld Metal AGENCY: Nuclear Regulatory Commission... Ferrite Content in Stainless Steel Weld Metal.'' This guide describes a method that the NRC staff considers acceptable for controlling ferrite content in stainless steel weld metal. Revision 4 updates...

  10. Radiation embrittlement of manganese-stabilized martensitic stainless steel

    SciTech Connect

    Gelles, D.S.; Hu, W.L.

    1986-12-01

    Fractographic examination has been performed on selected Charpy specimens of manganese stabilized martensitic stainless steels in order to identify the cause of irradiation embrittlement. Embrittlement was found to be partly due to enhanced failure at grain boundaries arising from precipitation. Microstructural examination of a specimen irradiated at higher temperature has demonstrated the presence of Fe-Cr-Mn chi phase, a body centered cubic intermetallic phase known to cause embrittlement. This work indicated that manganese stabilized martensitic stainless steels are prone to intermetallic phase formation which is detrimental to mechanical properties.

  11. Comparison of carbon fiber and stainless steel root canal posts.

    PubMed

    Purton, D G; Payne, J A

    1996-02-01

    This in vitro study compared physical properties of root canal posts made of carbon fiber-reinforced epoxy resin with those of stainless steel posts. Three-point bending tests were used to derive the transverse modulus of elasticity of the posts. Resin composite cores on the posts were subjected to tensile forces to test the bonds between the cores and posts. Carbon fiber posts appeared to have adequate rigidity for their designed purpose. The bond strength of the resin composite cores to the carbon fiber posts was significantly less than that to the stainless steel posts.

  12. Ozone decay on stainless steel and sugarcane bagasse surfaces

    NASA Astrophysics Data System (ADS)

    Souza-Corrêa, Jorge A.; Oliveira, Carlos; Amorim, Jayr

    2013-07-01

    Ozone was generated using dielectric barrier discharges at atmospheric pressure to treat sugarcane bagasse for bioethanol production. It was shown that interaction of ozone molecules with the pretreatment reactor wall (stainless steel) needs to be considered during bagasse oxidation in order to evaluate the pretreatment efficiency. The decomposition coefficients for ozone on both materials were determined to be (3.3 ± 0.2) × 10-8 for stainless steel and (2.0 ± 0.3) × 10-7 for bagasse. The results have indicated that ozone decomposition has occurred more efficiently on the biomass material.

  13. 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.

  14. Solidification and solid state transformations of austenitic stainless steel welds

    SciTech Connect

    Brooks, J A; Williams, J C; Thompson, A W

    1982-05-01

    The microstructure of austenitic stainless steel welds can contain a large variety of ferrite morphologies. It was originally thought that many of these morphologies were direct products of solidification. Subsequently, detailed work on castings suggested the structures can solidify either as ferrite or austenite. However, when solidification occurs by ferrite, a large fraction of the ferrite transforms to austenite during cooling via a diffusion controlled transformation. It was also shown by Arata et al that welds in a 304L alloy solidified 70-80% as primary ferrite, a large fraction of which also transformed to austenite upon cooling. More recently it was suggested that the cooling rates in welds were sufficiently high that diffusionless transformations were responsible for several commonly observed ferrite morphologies. However, other workers have suggested that even in welds, delta ..-->.. ..gamma.. transformations are diffusion controlled. A variety of ferrite morphologies have more recently been characterized by Moisio and coworkers and by David. The purpose of this paper is to provide further understanding of the evaluation of the various weld microstructures which are related to both the solidification behavior and the subsequent solid state transformations. To accomplish this, both TEM and STEM (Scanning Transmission Electron Microscopy) techniques were employed.

  15. Solidification microstructures in single-crystal stainless steel melt pools

    SciTech Connect

    Sipf, J.B.; Boatner, L.A.; David, S.A.

    1994-03-01

    Development of microstructure of stationary melt pools of oriented stainless steel single crystals (70%Fe-15%Ni-15%Cr was analyzed. Stationary melt pools were formed by electron-beam and gas-tungsten-arc heating on (001), (011), and (111) oriented planes of the austenitic, fcc-alloy crystals. Characterization and analysis of resulting microstructure was carried out for each crystallographic plane and welding method. Results showed that crystallography which favors ``easy growth`` along the <100> family of directions is a controlling factor in the microstructural formation along with the melt-pool shape. The microstructure was found to depend on the melting method, since each method forms a unique melt-pool shape. These results are used in making a three-dimensional reconstruction of the microstructure for each plane and melting method employed. This investigation also suggests avenues for future research into the microstructural properties of electron-beam welds as well as providing an experimental basis for mathematical models for the prediction of solidification microstructures.

  16. Quantification of fibrinogen adsorption onto 316L stainless steel.

    PubMed

    Gettens, Robert T T; Gilbert, Jeremy L

    2007-05-01

    Adsorption of the plasma protein fibrinogen (Fb) onto 316L stainless steel (316L SS) was observed and quantified using both in situ and ex situ atomic force microscopy techniques. Industry standard mechanical and electrochemical polishing techniques were used to prepare bulk alloy 316L SS samples, rendering the surfaces flat enough to directly observe and measure Fb adsorption. The data were analyzed kinetically using a Langmuir model. Largely irreversible adsorption was found on the 316L SS surface with an adsorption rate constant (k(o)) of 1.9 x 10(-4) mL microg(-1) s(-1) using the ex situ method and 1.7 x 10(-4) mL microg(-1) s(-1) using the in situ method. Additionally, protein conformation and assembly orientation on these surfaces were documented, where the adsorption pattern appeared random. Complete area coverage was never obtained. That is, after adsorption for over 5 time constants (5tau), voids in the structure were always observed.

  17. Final Report, Volume 1, Metallurgical Evaluation of Cast Duplex Stainless Steels and their Weldments

    SciTech Connect

    Wen, Songqing; Lundin, Carl, W.; Batten, Greg, W.

    2005-09-30

    Duplex stainless steels (DSS) are being specified for chloride containing environments due to their enhanced pitting and stress corrosion cracking resistance. They exhibit improved corrosion performance over the austenitic stainless steels. Duplex stainless steels also offer improved strength properties and are available in various wrought and cast forms. Selected grades of duplex stainless steel castings and their welds, in comparison with their wrought counterparts, were evaluated, regarding corrosion performance and mechanical properties and weldability. Multiple heats of cast duplex stainless steel were evaluated in the as-cast, solution annealed (SA) static cast and SA centrifugal cast conditions, while their wrought counterparts were characterized in the SA condition and in the form of as-rolled plate. Welding, including extensive assessment of autogenous welds and a preliminary study of composite welds (shielded metal arc weld (SMAW)), was performed. The evaluations included critical pitting temperature (CPT) testing, intergranular corrosion (IGC) testing, ASTM A923 (Methods A, B and C), Charpy impact testing, weldability testing (ASTM A494), ferrite measurement and microstructural evaluations. In the study, the corrosion performances of DSS castings were characterized and assessed, including the wrought counterparts for comparison. The evaluation filled the pore of lack of data for cast duplex stainless steels compared to wrought materials. A database of the pitting corrosion and IGC behavior of cast and wrought materials was generated for a greater depth of understanding for the behavior of cast duplex stainless steel. In addition, improved evaluation methods for DSS castings were developed according to ASTM A923, A262, G48 and A494. The study revealed that when properly heat treated according to the specification, (1) DSS castings have equal or better pitting and intergranular corrosion resistance than their wrought counterparts; (2) Welding reduces the

  18. Final Report, Volume 1, Metallurgical Evaluation of Cast Duplex Stainless Steels and their Weldments

    SciTech Connect

    Wen, Songqing; Lundin, Carl, W.; Batten, Greg, W.

    2005-09-30

    Duplex stainless steels (DSS) are being specified for chloride containing environments due to their enhanced pitting and stress corrosion cracking resistance. They exhibit improved corrosion performance over the austenitic stainless steels. Duplex stainless steels also offer improved strength properties and are available in various wrought and cast forms. Selected grades of duplex stainless steel castings and their welds, in comparison with their wrought counterparts, were evaluated, regarding corrosion performance and mechanical properties and weldability. Multiple heats of cast duplex stainless steel were evaluated in the as-cast, solution annealed (SA) static cast and SA centrifugal cast conditions, while their wrought counterparts were characterized in the SA condition and in the form of as-rolled plate. Welding, including extensive assessment of autogenous welds and a preliminary study of composite welds (shielded metal arc weld (SMAW)), was performed. The evaluations included critical pitting temperature (CPT) testing, intergranular corrosion (IGC) testing, ASTM A923 (Methods A, B and C), Charpy impact testing, weldability testing (ASTM A494), ferrite measurement and microstructural evaluations. In the study, the corrosion performances of DSS castings were characterized and assessed, including the wrought counterparts for comparison. The evaluation filled the pore of lack of data for cast duplex stainless steels compared to wrought materials. A database of the pitting corrosion and IGC behavior of cast and wrought materials was generated for a greater depth of understanding for the behavior of cast duplex stainless steel. In addition, improved evaluation methods for DSS castings were developed according to ASTM A923, A262, G48 and A494. The study revealed that when properly heat treated according to the specification, (1) DSS castings have equal or better pitting and intergranular corrosion resistance than their wrought counterparts; (2) Welding reduces the

  19. Analysis of the influence of electrolyte on surface finish in electropolished stainless steel

    NASA Astrophysics Data System (ADS)

    Hernando, M.; Núñez, P. J.; García, E.; Trujillo, R.

    2012-04-01

    Electropolishing is a surface finishing process of metals and alloys that enhances brilliant surface finishes with low surface roughness values. The most widely used electrolytes for the electropolishing of stainless steel are varying concentrations of phosphoric and sulphuric acid, and occasionally additives such as chromic acid. The objective of this study was to assess the performance of three commonly used industrial electrolytes in terms of the surface finish of electropolished stainless steel AISI 316L. Each electrolyte had varying sulphuric-phosphoric acid combinations with or without chromic acid. The following electropolishing conditions were assessed: current density, bath temperature, electropolishing time, and initial surface texture. The results revealed that adding chromic acid to the electrolyte did not significantly enhance surface finish, and electropolishing ranges were quite similar for all three electrolytes.

  20. Ultrasonic inspection of austenitic stainless steel welds with artificially produced stress corrosion cracks

    SciTech Connect

    Dugan, Sandra; Wagner, Sabine

    2014-02-18

    Austenitic stainless steel welds and nickel alloy welds, which are widely used in nuclear power plants, present major challenges for ultrasonic inspection due to the grain structure in the weld. Large grains in combination with the elastic anisotropy of the material lead to increased scattering and affect sound wave propagation in the weld. This results in a reduced signal-to-noise ratio, and complicates the interpretation of signals and the localization of defects. Mechanized ultrasonic inspection was applied to study austenitic stainless steel test blocks with different types of flaws, including inter-granular stress corrosion cracks (IGSCC). The results show that cracks located in the heat affected zone of the weld are easily detected when inspection from both sides of the weld is possible. In cases of limited accessibility, when ultrasonic inspection can be carried out only from one side of a weld, it may be difficult to distinguish between signals from scattering in the weld and signals from cracks.

  1. High-temperature brazing of stainless steel

    NASA Technical Reports Server (NTRS)

    Beuyukian, C. S.; Heisman, R. M.; Mitchell, M. J.

    1978-01-01

    Prevention of iron contamination of platens is eliminated by placing alumina/silica ceramic-fiber blankets between platens and carbon-steel plate. Carbon-steel plates provide rigidity and improve heat transfer.

  2. 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.

  3. Sealing of Al-containing stainless steel to lithia-alumina-silica glass-ceramic

    SciTech Connect

    Cassidy, R.T.; Moddeman, W.E.

    1989-12-31

    Recent work on a new glass-ceramic/alloy for pyrotechnic components is discussed. A newly developed family of austenitic stainless steels has been hermetically sealed to a widely used lithia-alumina-silica (LAS) glass-ceramic. These alloys, originally developed for high oxidation resistance, contain 4-5 wt% Al. The presence of Al offers several advantages from a glass or glass/ceramic sealing point of view: presence of a tenacious, stable oxide (Al{sub 2}O{sub 3}) on the alloys` surface as well as the fact that they can be strengthened during sealing via precipitation of a secondary phase, NiAl. In addition these new alloys offer lower material and machining costs and improved weldability compared to the widely used Ni-base superalloys.

  4. 37. REDUCTION PLANT DRYER Stainless steel screen cylinder, encased ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    37. REDUCTION PLANT - DRYER Stainless steel screen cylinder, encased within an outer steel shell (top half missing). As fish were tumbled by the rotating screen, they were cooked and dried by live steam piped into the dryer through overhead pipes. The dryer is mounted on a slight angle, aiding the process by moving the drying fish towards the exhaust end of the dryer. - Hovden Cannery, 886 Cannery Row, Monterey, Monterey County, CA

  5. Effect of ultrafine grain on tensile behaviour and corrosion resistance of the duplex stainless steel.

    PubMed

    Jinlong, Lv; Tongxiang, Liang; Chen, Wang; Limin, Dong

    2016-05-01

    The ultrafine grained 2205 duplex stainless steel was obtained by cold rolling and annealing. The tensile properties were investigated at room temperature. Comparing with coarse grained stainless steel, ultrafine grained sample showed higher strength and plasticity. In addition, grain size changed deformation orientation. The strain induced α'-martensite was observed in coarse grained 2205 duplex stainless steel with large strain. However, the grain refinement inhibited the transformation of α'-martensite;nevertheless, more deformation twins improved the strength and plasticity of ultrafine grained 2205 duplex stainless steel. In addition, the grain refinement improved corrosion resistance of the 2205 duplex stainless steel in sodium chloride solution.

  6. Bending Behavior of Porous Sintered Stainless Steel Fiber Honeycombs

    NASA Astrophysics Data System (ADS)

    Zou, Shuiping; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2017-02-01

    A novel porous honeycomb-type substrate has been developed using solid-state sintering stainless steel fibers. The porous sintered stainless steel fiber honeycombs (PSSSFH) are composed of a skeleton of sintered stainless steel fibers, three-dimensionally interconnected porous structures and multiple parallel microchannels. The bending behavior of the PSSSFH is investigated using three-point bending tests. Four stages, including an elastic stage, a yielding stage with a plateau, a hardening stage and a failure stage, are observed during the bending process of the PSSSFH. In the initial yielding stage, the bending forces increase slowly with displacement increasing, and then a yielding plateau follows, which is unique compared with other porous materials. Moreover, the structure parameters of the PSSSFH are varied to investigate the influence on the bending strength. It is determined that the multiple parallel microchannels can enhance the bending strength of porous stainless steel fiber sintered substrates (PSSFSS) and do not influence the variation trend of bending strength of PSSFSS with porosity increasing. The open ratio is conducive to increasing the bending strength, and the microchannel diameters ranging from 0.5 mm to 1.5 mm have little influence on the bending strength. In addition, both the increasing of sintering temperature and sintering time can strengthen the PSSSFH.

  7. Quantitative measurement and modeling of sensitization development in stainless steel

    SciTech Connect

    Bruemmer, S.M.; Atteridge, D.G.

    1992-09-01

    The state-of-the-art to quantitatively measure and model sensitization development in austenitic stainless steels is assessed and critically analyzed. A modeling capability is evolved and validated using a diverse experimental data base. Quantitative predictions are demonstrated for simple and complex thermal and thermomechanical treatments. Commercial stainless steel heats ranging from high-carbon Type 304 and 316 to low-carbon Type 304L and 316L have been examined including many heats which correspond to extra-low-carbon, nuclear-grade compositions. Within certain limits the electrochemical potentiokinetic reactivation (EPR) test was found to give accurate and reproducible measurements of the degree of sensitization (DOS) in Type 304 and 316 stainless steels. EPR test results are used to develop the quantitative data base and evolve/validate the quantitative modeling capability. This thesis represents a first step to evolve methods for the quantitative assessment of structural reliability in stainless steel components and weldments. Assessments will be based on component-specific information concerning material characteristics, fabrication history and service exposure. Methods will enable fabrication (e.g., welding and repair welding) procedures and material aging effects to be evaluated and ensure adequate cracking resistance during the service lifetime of reactor components. This work is being conducted by the Oregon Graduate Institute with interactive input from personnel at Pacific Northwest Laboratory.

  8. 6. DETAIL OF STAINLESS STEEL VISCERA CHUTE IN SOUTHEAST CORNER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. DETAIL OF STAINLESS STEEL VISCERA CHUTE IN SOUTHEAST CORNER OF LEVEL4; ENTRAILS WERE DROPPED INTO CHUTE, THEN PASSED THROUGH THE FLOOR TO THE GUT SHANTY ON LEVEL 3 TO BE SORTED AND CLEANED - Rath Packing Company, Hog Dressing Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  9. Bending Behavior of Porous Sintered Stainless Steel Fiber Honeycombs

    NASA Astrophysics Data System (ADS)

    Zou, Shuiping; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2016-12-01

    A novel porous honeycomb-type substrate has been developed using solid-state sintering stainless steel fibers. The porous sintered stainless steel fiber honeycombs (PSSSFH) are composed of a skeleton of sintered stainless steel fibers, three-dimensionally interconnected porous structures and multiple parallel microchannels. The bending behavior of the PSSSFH is investigated using three-point bending tests. Four stages, including an elastic stage, a yielding stage with a plateau, a hardening stage and a failure stage, are observed during the bending process of the PSSSFH. In the initial yielding stage, the bending forces increase slowly with displacement increasing, and then a yielding plateau follows, which is unique compared with other porous materials. Moreover, the structure parameters of the PSSSFH are varied to investigate the influence on the bending strength. It is determined that the multiple parallel microchannels can enhance the bending strength of porous stainless steel fiber sintered substrates (PSSFSS) and do not influence the variation trend of bending strength of PSSFSS with porosity increasing. The open ratio is conducive to increasing the bending strength, and the microchannel diameters ranging from 0.5 mm to 1.5 mm have little influence on the bending strength. In addition, both the increasing of sintering temperature and sintering time can strengthen the PSSSFH.

  10. 73. View of line of stainless steel coolant storage tanks ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    73. View of line of stainless steel coolant storage tanks for bi-sodium sulfate/water coolant solution at first floor of transmitter building no. 102. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  11. Cataract Section Across Temporary Stainless-Steel Sutures

    PubMed Central

    MacDonald, R. Keith

    1965-01-01

    The purpose of the technique described was to combine the advantages of a cleanedged Graefe-knife incision with those of safety and near-perfect apposition offered by preplaced sutures: a preliminary to cataract extraction. Uncuttable preplaced 2-mm. stainless steel sutures were finally replaced after completion of the incision by attached braided silk for closure purposes. PMID:14291461

  12. New equation of state for stainless steel 347

    SciTech Connect

    Boettger, J.C.

    1993-12-01

    A new SESAME equation of state (EOS) for stainless steel 347 has been generated using the computer program GRIZZLY, and has been added to the SESAME EOS library as material number 4271. This new EOS is superior to its predecesser (material number 4270) in several respects.

  13. Method of forming dynamic membrane on stainless steel support

    NASA Technical Reports Server (NTRS)

    Gaddis, Joseph L. (Inventor); Brandon, Craig A. (Inventor)

    1988-01-01

    A suitable member formed from sintered, powdered, stainless steel is contacted with a nitrate solution of a soluble alkali metal nitrate and a metal such as zirconium in a pH range and for a time sufficient to effect the formation of a membrane of zirconium oxide preferably including an organic polymeric material such as polyacrylic acid.

  14. 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).

  15. Battery and fuel cell electrodes containing stainless steel charging additive

    DOEpatents

    Zuckerbrod, David; Gibney, Ann

    1984-01-01

    An electrode for use in electrochemical energy cells is made, comprising a hydrophilic layer and a hydrophobic layer, where the hydrophilic layer comprises a hydrophilic composite which includes: (i) carbon particles; (ii) stainless steel particles; (iii) a nonwetting agent; and (iv) a catalyst, where at least one current collector contacts said composite.

  16. Behavior of stainless steels in pressurized water reactor primary circuits

    NASA Astrophysics Data System (ADS)

    Féron, D.; Herms, E.; Tanguy, B.

    2012-08-01

    Stainless steels are widely used in primary circuits of pressurized water reactors (PWRs). Operating experience with the various grades of stainless steels over several decades of years has generally been excellent. Nevertheless, stress corrosion failures have been reported in few cases. Two main factors contributing to SCC susceptibility enhancement are investigated in this study: cold work and irradiation. Irradiation is involved in the stress corrosion cracking and corrosion of in-core reactor components in PWR environment. Irradiated assisted stress corrosion cracking (IASCC) is a complex and multi-physics phenomenon for which a predictive modeling able to describe initiation and/or propagation is not yet achieved. Experimentally, development of initiation smart tests and of in situ instrumentation, also in nuclear reactors, is an important axis in order to gain a better understanding of IASCC kinetics. A strong susceptibility for SCC of heavily cold worked austenitic stainless steels is evidenced in hydrogenated primary water typical of PWRs. It is shown that for a given cold-working procedure, SCC susceptibility of austenitic stainless steels materials increases with increasing cold-work. Results have shown also strong influences of the cold work on the oxide layer composition and of the maximum stress on the time to fracture.

  17. [The question of nickel release from stainless steel cooking pots].

    PubMed

    Vrochte, H; Schätzke, M; Dringenberg, E; Wölwer-Rieck, U; Büning-Pfaue, H

    1991-09-01

    For three items of foods (rhubarb, spinach, sauerkraut) the possible release of nickel (by means of AAS) was analysed, a release which may be caused by a possible corrosive effect of the concerned (oxalic-, milk-, vinegar-) acids (as well as common salt) within a normal domestic food-preparation. For this analysis stainless steel cooking pots of different manufacturers, various types and in a representative selection and quantity were taken into consideration; the detailed analyses were extended so far that clear statistical evaluations were possible. This method complies regulations for accuracy to determine traces of heavy metal. For all three analysed food-stuffs an identical result was reached that no nickel release from the stainless steel cooking pots into the food was found. Differences of the various stainless steel cooking pots with regard to their surfaces' quality or their origin (manufacturers) were not yielded, either. All detected concentrations of nickel are within the reach of the natural nickel content of the analysed food-stuffs and their amount is even much lower than other food's content of nickel. This leads up to the conclusion that the former view of a possible nickel release of stainless steel cooking pots has to be revised because these assumptions were not confirmed in the presented results of this analysis and therefore have to be regarded as not correct.

  18. Immobilization of mesoporous silica particles on stainless steel plates

    NASA Astrophysics Data System (ADS)

    Pasqua, Luigi; Morra, Marco

    2017-03-01

    A preliminary study aimed to the nano-engineering of stainless steel surface is presented. Aminopropyl-functionalized mesoporous silica is covalently and electrostatically anchored on the surface of stainless steel plates. The anchoring is carried out through the use of a nanometric spacer, and two different spacers are proposed (both below 2 nm in size). The first sample is obtained by anchoring to the stainless steel amino functionalized, a glutaryl dichloride spacer. This specie forms an amide linkage with the amino group while the unreacted acyl groups undergo hydrolysis giving a free carboxylic group. The so-obtained functionalized stainless steel plate is used as substrate for anchoring derivatized mesoporous silica particles. The second sample is prepared using 2-bromo-methyl propionic acid as spacer (BMPA). Successively, the carboxylic group of propionic acid is condensed to the aminopropyl derivatization on the external surface of the mesoporous silica particle through covalent bond. In both cases, a continuous deposition (coating thickness is around 10 μm) is obtained, in fact, XPS data do not reveal the metal elements constituting the plate. The nano-engineering of metal surfaces can represent an intriguing opportunity for producing long-term drug release or biomimetic surface.

  19. Stainless steel 301 and Inconel 718 hydrogen embrittlement

    NASA Technical Reports Server (NTRS)

    Allgeier, R. K.; Forman, R.

    1970-01-01

    Conditions and results of tensile tests of 26 Inconel 718 and four cryoformed stainless steel specimens are presented. Conclusions determine maximum safe hydrogen operating pressure for cryogenic pressure vessels and provide definitive information concerning flaw growth characteristics under the most severe temperature and pressure conditions

  20. Friction and wear of selected metals and alloys in sliding contact with AISI 440 C stainless steel in liquid methane and in liquid natural gas

    NASA Technical Reports Server (NTRS)

    Wisander, D. W.

    1978-01-01

    Aluminum, titanium, beryllium, nickel, iron, copper, and several copper alloys were run in sliding contact with AISI 440C in liquid methane and natural gas. All of the metals run except copper and the copper alloys of tin and tin-lead showed severely galled wear scars. Friction coefficients varied from 0.2 to 1.0, the lowest being for copper, copper-17 wt. % tin, and copper-8 wt. % tin-22 wt. % lead. The wear rate for copper was two orders of magnitude lower than that of the other metals run. An additional order of magnitude of wear reduction was achieved by the addition of tin and/or lead to copper.

  1. 76 FR 13357 - Stainless Steel Sheet and Strip in Coils From Mexico; Correction Notice to Amended Final Results...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-11

    ... International Trade Administration Stainless Steel Sheet and Strip in Coils From Mexico; Correction Notice to... administrative review for stainless steel sheet and strip in coils from Mexico. See Stainless Steel Sheet and.... See Stainless Steel Sheet and Strip in Coils from Mexico; Final Results of Antidumping...

  2. Phase formation at bonded vanadium and stainless steel interfaces

    SciTech Connect

    Summers, T.S.E.

    1992-01-01

    The interface between vanadium bonded to stainless steel was studies to determine whether a brittle phase formed during three joining operations. Inertia friction welds between V and 21-6-9 stainless steel were examined using TEM. In the as-welded condition, a continuous, polygranular intermetallic layer about 0.25 {mu}m thick was present at the interface. This layer grew to about 50 {mu}m thick during heat treatment at 1000{degrees}C for two hours. Analysis of electron diffraction patterns confirmed that this intermetallic was the {omega} phase. The interface between vanadium and type 304, SANDVIK SAF 2205, and 21-6-9 stainless steel bonded by a co-extrusion process had intermetallic particles at the interface in the as-extruded condition. Heat treatment at 1000{degrees}C for two hours caused these particles to grow into continuous layers in all three cases. Based on the appearance, composition and hardness of this interfacial intermetallic, it was also concluded to be {omega} phase. Bonding V to type 430 stainless steel by co-extrusion caused V-rich carbides to form at the interface due to the higher concentration of C in the type 430 than in the other stainless steels investigated. The carbide particles initially present grew into a continuous layer during a two-hour heat treatment at 1000{degrees}C. Co-hipping 21-6-9 stainless steel tubing with V rod resulted in slightly more concentric specimens than the co-extruded ones, but a continuous layer of the {omega} phase formed during the hipping operation. This brittle layer could initiate failure during subsequent forming operations. The vanadium near the stainless steel interface in the co-extruded and co-hipped tubing in some cases was harder than before heat treatment. It was concluded that this hardening was due to thermal straining during cooling following heat treatment and that thermal strains might present a greater problem than seen here when longer tubes are used in actual applications.

  3. Constitutive flow behaviour of austenitic stainless steels under hot deformation: artificial neural network modelling to understand, evaluate and predict

    NASA Astrophysics Data System (ADS)

    Mandal, Sumantra; Sivaprasad, P. V.; Venugopal, S.; Murthy, K. P. N.

    2006-09-01

    An artificial neural network (ANN) model is developed to predict the constitutive flow behaviour of austenitic stainless steels during hot deformation. The input parameters are alloy composition and process variables whereas flow stress is the output. The model is based on a three-layer feed-forward ANN with a back-propagation learning algorithm. The neural network is trained with an in-house database obtained from hot compression tests on various grades of austenitic stainless steels. The performance of the model is evaluated using a wide variety of statistical indices. Good agreement between experimental and predicted data is obtained. The correlation between individual alloying elements and high temperature flow behaviour is investigated by employing the ANN model. The results are found to be consistent with the physical phenomena. The model can be used as a guideline for new alloy development.

  4. Mechanical resistance of carbon and stainless steel hand instruments used in a reciprocating handpiece

    PubMed Central

    Piasecki, Lucila; Al-Sudani, Dina; Rubini, Alessio Giansiracusa; Sonnino, Giampaolo; Bossù, Maurizio; Testarelli, Luca; Di Giorgio, Roberto; da Silva-Neto, Ulisses Xavier; Brandão, Christian Giampietro; Gambarini, Gianluca

    2013-01-01

    Summary Aim The manual files are still widely used for initial canal negotiation prior the use of nickel-titanium shaping instruments, to determine working length and to verify patency. A mechanical glide path can be performed using manual files with handpieces, such as M4 Handpiece (SybronEndo, USA) that allows a 30°/30° reciprocating motion. The Pathfinders (SybronEndo, USA) are hand files designed to negotiate complex canals, made from stainless steel (SS) or carbon steel (CS) alloys. The aim of this in vitro study was to compare cyclic fatigue resistance of these two different types of manual Pathfinder instruments used in a M4 reciprocating handpiece in double curved artificial canals. Materials and methods Manual instruments designed for glide path (size #9 ISO .02 taper) made from different alloys were selected: Group SS -stainless steel Pathfinders (Sybron Endo) and Group CS - carbon steel Pathfinders size K2 (Sybron Endo). Ten instruments of each group were tested for resistance to cyclic fatigue with a reciprocating M4 handpiece inside an artificial S-shaped canal; the time to fracture was recorded for each file and data were statistically analyzed (ANOVA). Results Mean values (and SD) were 527 (± 89) seconds for the CS instruments and 548 (± 104) seconds for the SS files. No significant differences were observed between groups (p=0,062). Conclusions According to the results, both carbon and stainless steel instruments presented similar fatigue resistance when used with M4 reciprocating handpiece in double curved canals. PMID:24611091

  5. Cavitation Erosion of Sensitized UNS S31803 Duplex Stainless Steels

    NASA Astrophysics Data System (ADS)

    Mitelea, Ion; Micu, Lavinia Mădălina; Bordeaşu, Ilare; Crăciunescu, Corneliu Marius

    2016-05-01

    During processing or use, duplex steels can be subjected to heating at high temperatures that can affect their behavior. This work aims to correlate the influence of the sensitization treatment on the ultrasonic cavitation erosion behavior of a UNS S31803 (X2CrNiMoN22-5-3) duplex stainless steel. Duplex stainless steels, formed as a result of rapid cooling after solution annealing, are sensitized at temperatures of 475 and 850 °C, respectively, leading to hardening and embrittlement due to the spinodal decomposition of the ferrite and the precipitation of secondary phases. The ultrasonic cavitation erosion experiments showed that the sensitization at 850 °C reduced the mean depth of erosion by about 11% and the mean depth of erosion rate by 28%. By contrast, the sensitization at 475 °C deteriorates the cavitation erosion resistance, increasing the erosion parameters by up to 22%, compared to the solution annealed state.

  6. Achievement of a superpolish on bare stainless steel

    SciTech Connect

    Howells, M.R.; Casstevens, J.

    1997-08-01

    We report the achievement of a superpolished surface, suitable for x-ray reflection, on bare stainless steel. The rms roughness obtained on various samples varied from 2.2 to 4.2 {angstrom}, as measured by an optical profiler with a bandwidth 0.29-100 mm{sup -1}. The type 17-4 PH precipitation-hardening stainless steel used to make the mirrors is also capable of ultrastability and has good manufactureability. This combination of properties makes it an excellent candidate material for mirror substrates. We describe the successful utilization of this type of steel in making elliptical-cylinder mirrors for a soft-x-ray microprobe system at the Advanced Light Source, and discuss possible for its unusual stability and polishability.

  7. Enabling Inexpensive Metallic Alloys as SOFC Interconnects: An Investigation into Hybrid Coating Technologies to Deposit Nanocomposite Functional Coatings on Ferritic Stainless Steel

    SciTech Connect

    Gannon, Paul; Gorokhovsky, Vladimir I.; Deibert, Max; Smith, Richard J.; Kayani, Asghar N.; White, P T.; Sofie, Stephen W.; Yang, Z Gary; Mccready, David E.; Visco, S.; Jacobson, C.; Kurokawa, H.

    2007-11-01

    Reduced operating temperatures (600-800°C) of Solid Oxide Fuel Cells (SOFCs) may enable the use of inexpensive ferritic steels as interconnects. Due to the demanding SOFC interconnect operating environment, protective coatings are required to increase long-term stability. In this study, large area filtered arc deposition (LAFAD) and hybrid filtered arc-assisted electron beam physical vapor deposition (FA-EBPVD) technologies were used to deposit two-segment coatings with Cr-Al-Y-O nanocomposite bottom segments and Mn-Co-O spinel-based top segments. Coatings were deposited on ferritic steels and subsequently annealed in air for various times. Surface oxidation was investigated using SEM/EDS, XRD and RBS analyses. Cr-volatilization was evaluated by transpiration and ICP-MS analysis of the resultant condensate. Time dependent Area Specific Resistance (ASR) was studied using the four-point technique. The oxidation behavior, Cr volatilization rate, and ASR of coated and uncoated samples are reported. Significant long-term (>1,000 hours) surface stability, low ASR, and dramatically reduced Cr-volatility were observed with the coated specimens. Improvement mechanisms, including the coating diffusion barrier properties and electrical conductivity are discussed.

  8. Aging degradation of cast stainless steels: Effects on mechanical properties

    SciTech Connect

    Chopra, O.K.; Chung, H.M.

    1987-06-01

    A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water operating conditions. Mechanical property data are presented from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 450, 400, 350, 320, and 290/sup 0/C. The results indicate that thermal aging increases the tensile strength and decreases the impact energy, J/sub IC/, and tearing modulus of the steels. Also, the ductile-to-brittle transition curve shifts to higher temperatures. The fracture toughness results are consistent with the Charpy-impact data, i.e., the relative reduction in J/sub IC/ is similar to the relative decrease in impact energy. The ferrite content and concentration of C in the steel have a strong effect on the overall process of low-temperature embrittlement. The low-carbon CF-3 steels are the most resistant and Mo-containing CF-8M steels are most susceptible to embrittlement. Weakening of the ferrite/austenite phase boundaries by carbide precipitates has a significant effect on the kinetics and extent of embrittlement of the high-carbon CF-8 and CF-8M steels, particularly after aging at temperatures greater than or equal to400/sup 0/C. The influence of N content and distribution of ferrite on loss of toughness are discussed. The data also indicate that existing correlations do not accurately represent the embrittlement behavior over the temperature range 280 to 450/sup 0/C, i.e., extrapolation of high-temperature data to reactor temperatures may not be valid for some compositions of cast stainless steel.

  9. The influence of Si content on the oxidation behavior of Type 430 stainless steels

    SciTech Connect

    Alman, D.E.; Jablonski, P.D.

    2007-09-01

    Trace “alloying” elements can significantly affect alloy performance. One example is the effect of residual Si content on the oxidation behavior of stainless steels. Small amounts of Si can form a continuous SiO2 layer at the metal-oxide scale interface. This is beneficial for enhancing oxidation resistance; however it is detrimental for fuel cell interconnect application, as SiO2 is an electrical insulator. In order to assess the effect of SiO2 on the performance of Type 430 ferritic steel, a potential interconnect alloy, a series of custom 430 alloys were melted and reduced to sheet with controlled Si contents (ranging from <0.01 to 0.1 wt% Si). Oxidation tests were conducted at 800oC in moist air. The behavior was compared to a commercial Type 430 alloy (with 0.4 wt%Si) and Crofer 22APU. It was found that for the 430 alloys, the oxidation rate increased with decreasing Si content. However, after 4000 hour of exposure, the mass gain for the low Si 430 alloys was comparable to Crofer 22APU.

  10. Antibacterial activity against Porphyromonas gingivalis and biological characteristics of antibacterial stainless steel.

    PubMed

    Zhang, Dan; Ren, Ling; Zhang, Yang; Xue, Nan; Yang, Ke; Zhong, Ming

    2013-05-01

    To evaluate the possibility of an alternative to the traditional orthodontic stainless steel implants, the antibacterial activity against Porphyromonas gingivalis (P. gingivalis) and the related cytotoxicity of a type 304 Cu bearing antibacterial stainless steel were studied. The results indicated that the antibacterial stainless steel showed excellent antibacterial property against P. gingivalis, compared with the control steel (a purchased medical grade 304 stainless steel). Compared to the control steel, there were fewer bacteria on the surface of the antibacterial stainless steel, with significant difference in morphology. The cytotoxicities of the antibacterial stainless steel to both MG-63 and KB cells were all grade 1, the same as those of the control steel. There were no significant differences in the apoptosis rates on MG-63 and KB cells between the antibacterial stainless steel and the control steel. This study demonstrates that the antibacterial stainless steel is possible to reduce the incidence of implant-related infections and can be a more suitable material for the micro-implant than the conventional stainless steel in orthodontic treatment.

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

    SciTech Connect

    Zhang, Yan; Yu, Jianqiang; Sun, Kai; Zhu, Yukun; Bu, Yuyu; Chen, Zhuoyuan

    2014-05-01

    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 by 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.

  12. 2012 ACCOMPLISHMENTS - TRITIUM AGING STUDIES ON STAINLESS STEELS

    SciTech Connect

    Morgan, M.

    2013-01-31

    This report summarizes the research and development accomplishments during FY12 for the tritium effects on materials program. The tritium effects on materials program is designed to measure the long-term effects of tritium and its radioactive decay product, helium-3, on the structural properties of forged stainless steels which are used as the materials of construction for tritium reservoirs. The FY12 R&D accomplishments include: (1) Fabricated and Thermally-Charged 150 Forged Stainless Steel Samples with Tritium for Future Aging Studies; (2) Developed an Experimental Plan for Measuring Cracking Thresholds of Tritium-Charged-and-Aged Steels in High Pressure Hydrogen Gas; (3) Calculated Sample Tritium Contents For Laboratory Inventory Requirements and Environmental Release Estimates; (4) Published report on “Cracking Thresholds and Fracture Toughness Properties of Tritium-Charged-and-Aged Stainless Steels”; and, (5) Published report on “The Effects of Hydrogen, Tritium, and Heat Treatment on the Deformation and Fracture Toughness Properties of Stainless Steels”. These accomplishments are highlighted here and references given to additional reports for more detailed information.

  13. Wetting Properties of Liquid Lithium on Stainless Steel and Enhanced Stainless Steel Surfaces

    NASA Astrophysics Data System (ADS)

    Fiflis, P.; Xu, W.; Raman, P.; Andruczyk, D.; Ruzic, D. N.; Curreli, D.

    2012-10-01

    Research into lithium as a first wall material has proven its ability to effectively getter impurities and reduce recycling of hydrogen ions at the wall. Current schemes for introducing lithium into a fusion device consist of lithium evaporators, however, as these devices evolve from pulsed to steady state, new methods will need to be employed such as the LIMIT concept of UIUC, or thin flowing film lithium walls. Critical to their implementation is understanding the interactions of liquid lithium with various surfaces. One such interaction is the wetting of materials by lithium, which may be characterized by the contact angle between the lithium and the surface. Experiments have been performed at UIUC into the contact angle of liquid lithium with a given surface, as well as methods to increase it. To reduce the oxidation rate of the droplets, the experiments were performed in vacuum, using a lithium injector to deposit drops on each surface. Among the materials investigated are stainless steel, both untreated and coated with a diamond like carbon (DLC) layer, molybdenum, and boronized molybdenum. The contact angle and its dependence on temperature is measured.

  14. Phase-dependent corrosion of titanium-to-stainless steel joints brazed by Ag-Cu eutectic alloy filler and Ag interlayer

    NASA Astrophysics Data System (ADS)

    Lee, M. K.; Park, J. J.; Lee, J. G.; Rhee, C. K.

    2013-08-01

    The electrochemical corrosion properties of Ti-STS dissimilar joints brazed by a 72Ag-28Cu alloy filler and an Ag interlayer were studied in a 3.5% NaCl solution using potentiodynamic polarization and ac impedance spectroscopy. For a joint with a layered structure of Ti(base)/TiAg/Ag solid solution/Ag-Cu eutectic/STS(base), galvanic corrosion mostly occurred in the TiAg phase with a severe material loss, indicating that the TiAg layer acted as an anode in the galvanic couple in the layered joint. The Ag-rich solid solution layer was also corroded to a certain extent, but the corrosion in this layer was dominated by the selective pitting corrosion of the eutectic Cu-rich phase. With an increase in the brazing temperature, the Cu-rich phases disappeared owing to the enhanced isothermal solidification effect, leading to an improvement of the corrosion resistance.

  15. 46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Carbon-steel or alloy-steel castings. 59.20-1 Section 59... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The...

  16. 46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Carbon-steel or alloy-steel castings. 59.20-1 Section 59... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The...

  17. 46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Carbon-steel or alloy-steel castings. 59.20-1 Section 59... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The...

  18. 46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Carbon-steel or alloy-steel castings. 59.20-1 Section 59... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The...

  19. 46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Carbon-steel or alloy-steel castings. 59.20-1 Section 59... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The...

  20. Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel

    SciTech Connect

    Li, Zhangbo; Lo, Wei-Yang; Chen, Yiren; Pakarinen, Janne; Wu, Yaqiao; Allen, Todd; Yang, Yong

    2015-08-08

    To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ~315 °C to 0.08 dpa (5.6 × 1019 n/cm2 E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10-9 dpa/s was found to induce spinod,al decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. Lastly, The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition.