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Sample records for pre-strained 304l stainless

  1. Texture and yield stress of pre-strained 304L stainless steel

    SciTech Connect

    Bennett, K.; Dreele, R.B. von; Gray, G.T. III; Chen, S.R.

    1998-08-01

    The evolution of texture and yield stress in 304L stainless steel is investigated as a function of deformation to large plastic strains. Steel bars quasi-statically upset forged at a strain rate of 0.001 s{sup {minus}1} to true strains of 0, 0.5, 1.0 and 1.8 were found to acquire their texture ({approximately}3.0 m.r.d.) in the first 0.5 strain with (110) poles highly aligned parallel to the compression direction independent of whether the pre-forged starting material was in a cold worked or annealed (1,050 C for 1 hour) condition. The same bars, when strained at room temperature show an incremental yield with pre-strain regardless of strain rate (10{sup {minus}1} or 10{sup {minus}3}s{sup {minus}1}) or thermal history, though annealed bars yield at slightly lower stresses. At 77 K and strain rate 10{sup {minus}3}s{sup {minus}1}, the annealed 304L exhibits more pronounced strain-hardening behavior than the 304L forged in a cold-worked condition.

  2. Texture and Yield Stress of Pre-Strained 304L Stainless Steel

    SciTech Connect

    Bennett, K.; Von Dreele, B.; Gray, G.T. III; Chen, S.R.

    1997-06-23

    The evolution of texture and yield stress in 304L stainless steel is investigated as a function of deformation to large plastic strains. Steel bars quasi-statically upset forged at a strain rate of 0.001s{sup -1} to true strains of 0, 0.5, 1.0 and 1.8 were found to acquire their texture ({approximately}3.0 m.r.d.) in the first 0.5 strain with (110) poles highly aligned parallel to the compression direction independent of whether the pre-forged starting material was in a cold worked or annealed (1050 C for 1 hour) condition. The same bars, when strained at room temperature show an incremental yield with pre-strain regardless of strain rate (10{sup -1} or 10{sup -3}s{sup -1}) or thermal history, though annealed bars yield at slightly lower stresses. At 77 K and strain rate 10{sup -3}s{sup -1}, the annealed 304L exhibits more pronounced strain-hardening behavior than the 304L forged in a cold-worked condition.

  3. 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.

  4. 304L stainless steel resistance to cesium chloride

    SciTech Connect

    Graves, C.E.

    1998-08-27

    B and W Hanford Company have two Oak Ridge National Laboratory (ORNL) Type 4 canisters filled with cesium chloride (CsCl) originally produced at WESF (Waste Encapsulation and Storage Facility). These canisters are constructed of 304L stainless steel per drawing ORNL 970-294. Instead of removing the CsCl from the Type 4 canisters and repacking into an Inner Capsule, it is intended (for ALARA, schedule and cost purposes) that the Type 4 canisters be decontaminated (scrubbed) and placed [whole] inside a Type ``W`` overpack. The overpack is constructed from 316L stainless steel. Several tests have been run by Pacific Northwest National Laboratory (PNNL) over the. years documenting the corrosion compatibility of 316L SS with CsCl (Bryan 1989 and Fullam 1972). However, no information for 304L SS compatibility is readily available. This document estimates the corrosion resistance of 304L stainless steel in a WESF CsCl environment as it compares with that of 316L stainless steel.

  5. Microstructures of laser deposited 304L austenitic stainless steel

    SciTech Connect

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

    2000-05-22

    Laser deposits fabricated from two different compositions of 304L stainless steel powder were characterized to determine the nature of the solidification and solid state transformations. One of the goals of this work was to determine to what extent novel microstructure consisting of single-phase austenite could be achieved with the thermal conditions of the LENS [Laser Engineered Net Shape] process. Although ferrite-free deposits were not obtained, structures with very low ferrite content were achieved. It appeared that, with slight changes in alloy composition, this goal could be met via two different solidification and transformation mechanisms.

  6. Abnormal grain growth in AISI 304L stainless steel

    SciTech Connect

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

    2014-11-15

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

  7. Weld solidification cracking in 304 to 304L stainless steel

    SciTech Connect

    Hochanadel, Patrick W; Lienert, Thomas J; Martinez, Jesse N; Martinez, Raymond J; Johnson, Matthew Q

    2010-01-01

    A series of annulus welds were made between 304 and 304L stainless steel coaxial tubes using both pulsed laser beam welding (LBW) and pulsed gas tungsten arc welding (GTAW). In this application, a change in process from pulsed LBW to pulsed gas tungsten arc welding was proposed to limit the possibility of weld solidification cracking since weldability diagrams developed for GTAW display a greater range of compositions that are not crack susceptible relative to those developed for pulsed LBW. Contrary to the predictions of the GTAW weldability diagram, cracking was found. This result was rationalized in terms of the more rapid solidification rate of the pulsed gas tungsten arc welds. In addition, for the pulsed LBW conditions, the material compositions were predicted to be, by themselves, 'weldable' according to the pulsed LBW weldability diagram. However, the composition range along the tie line connecting the two compositions passed through the crack susceptible range. Microstructurally, the primary solidification mode (PSM) of the material processed with higher power LBW was determined to be austenite (A), while solidification mode of the materials processed with lower power LBW apparently exhibited a dual PSM of both austenite (A) and ferrite-austenite (FA) within the same weld. The materials processed by pulsed GT A W showed mostly primary austenite solidification, with some regions of either primary austenite-second phase ferrite (AF) solidification or primary ferrite-second phase austenite (FA) solidification. This work demonstrates that variations in crack susceptibility may be realized when welding different heats of 'weldable' materials together, and that slight variations in processing can also contribute to crack susceptibility.

  8. Microbiological influenced corrosion resistance characteristics of a 304L-Cu stainless steel against Escherichia coli.

    PubMed

    Nan, Li; Xu, Dake; Gu, Tingyue; Song, Xiu; Yang, Ke

    2015-03-01

    Cu-bearing antibacterial stainless steels have been gaining popularity in recent years due to their strong antibacterial performances. However, only a few studies were reported for their actual performances against microbiologically influenced corrosion (MIC). In this study, electrochemical methods and surface analytical techniques were applied to study the MIC resistance characteristics of a 304L-Cu stainless steel (SS) against Escherichia coli in comparison with 304L SS as control. Corrosion tests for specimens after a 21-day exposure to a Luria-Bertani (LB) culture medium with E. coli demonstrated that the 304L-Cu SS considerably reduced the maximum MIC pit depth and the specific weight loss compared with 304L SS (8.3μm and 0.2mg/cm(2) vs. 13.4μm and 0.6mg/cm(2)). Potentiodynamic polarization tests showed that the corrosion current density of the 304L-Cu SS was as much as 4 times lower than that of the 304L SS, indicating that the 304L-Cu SS is a better choice for applications in MIC-prone environments.

  9. HYDROGEN-ASSISTED FRACTURE IN FORGED TYPE 304L AUSTENITIC STAINLESS STEEL

    SciTech Connect

    Switzner, Nathan; Neidt, Ted; Hollenbeck, John; Knutson, J.; Everhart, Wes; Hanlin, R.; Bergen, R.; Balch, D. K.

    2012-09-06

    Austenitic stainless steels generally have good resistance to hydrogen-assisted fracture; however, structural designs for high-pressure gaseous hydrogen are constrained by the low strength of this class of material. Forging is used to increase the low strength of austenitic stainless steels, thus improving the efficiency of structural designs. Hydrogen-assisted racture, however, depends on microstructural details associated with manufacturing. In this study, hydrogen-assisted fracture of forged type 304L austenitic stainless steel is investigated. Microstructural variation in multi-step forged 304L was achieved by forging at different rates and temperatures, and by process annealing. High internal hydrogen content in forged type 304L austenitic stainless steel is achieved by thermal precharging in gaseous hydrogen and results in as much as 50% reduction of tensile ductility.

  10. Dynamic Strength of 304L stainless steel under impact

    NASA Astrophysics Data System (ADS)

    Werdiger, Meir; Bakshi, Lior; Glam, Benny; Pistinner, Shlomi

    2011-06-01

    We use the Asay self consistent technique to analyze the effects of pressure hardening and strain hardening on SS304L. Previously unloading experiment has been used to infer the strength of this material at high pressure, and recently the Johnson-Cook (JC) model has been calibrated at low strain rate. Release and reshock experiments with impact velocity range of 300-1700 m/s were preformed. We used VISAR to extract the particle velocity of the SS304L- LiF window interface. The velocity profile compared to hydrodynamic simulation using JC model. Our unloading experiments have clearly demonstrate that the material yield but does not fail. Thus infer substantial effect of pressure hardening.

  11. Texture evolution of warm-rolled and annealed 304L and 316L austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Lindell, D.

    2015-04-01

    The brass-to-copper rolling texture transition is observed during warm rolling austenitic stainless steels. In the current paper austenitic stainless steels 304L and 316L have been subjected to warm rolling at 700°C to 90% reduction. The evolution of microstructure and texture during subsequent annealing has been studied using dilatometry and electron backscatter diffraction. Recrystallisation texture for 304L was primarily cube with some retained rolling texture while 316L only had retained rolling texture. The different behaviour between the two steels is believed to originate from differences in molybdenum content.

  12. Weldability of tritium-charged 304L stainless steel

    SciTech Connect

    Kanne, W R; Angerman, C L; Eberhard, B J

    1987-02-01

    Attempts to repair the wall of C-Reactor Tank at the Savannah River Plant were halted when Gas Tungsten Arc (GTA) welds joining patches to the wall developed toe cracks in the heat affected zone (HAZ). The cause of the toe cracks was investigated by welding on 304L samples that were tritium charged and aged to produce helium. Helium embrittlement was shown to be the likely cause of weld toe cracking in C-Reactor Tank. GTA welds made on helium impregnated 304L produced toe cracks identical to those that caused leaking patches during C-Reactor Tank repair. Heating of a sample to remove deuterium and tritium without removing helium did not reduce cracking susceptibility. Low heat input and spot GTA welds also produced cracks, indicating possible problems using these techniques for reactor repair. However, cracks were not produced by solid state resistance welds, or by a very low heat GTA pass that did not produce melting. This indicates that non-melting or low tensile stress techniques could be used for repair.

  13. Surface working of 304L stainless steel: Impact on microstructure, electrochemical behavior and SCC resistance

    SciTech Connect

    Acharyya, S.G.; Khandelwal, A.; Kain, V.; Kumar, A.; Samajdar, I.

    2012-10-15

    The effect of surface working operations on the microstructure, electrochemical behavior and stress corrosion cracking resistance of 304L stainless steel (SS) was investigated in this study. The material was subjected to (a) solution annealing (b) machining and (c) grinding operations. Microstructural characterization was done using stereo microscopy and electron back scattered diffraction (EBSD) technique. The electrochemical nature of the surfaces in machined, ground and solution annealed condition were studied using potentiodynamic polarization and scanning electrochemical microscopy (SECM) in borate buffer solution. The stress corrosion cracking resistance of 304L SS in different conditions was studied by exposing the samples to boiling MgCl{sub 2} environment. Results revealed that the heavy plastic deformation and residual stresses present near the surface due to machining and grinding operations make 304L SS electrochemically more active and susceptible to stress corrosion cracking. Ground sample showed highest magnitude of current density in the passive potential range followed by machined and solution annealed 304L SS. Micro-electrochemical studies established that surface working promotes localized corrosion along the surface asperities which could lead to crack initiation. - Highlights: Black-Right-Pointing-Pointer Machining/grinding produce extensive grain fragmentation near the surface of 304L SS. Black-Right-Pointing-Pointer Machining/grinding result in martensitic transformation near the surface of 304L SS. Black-Right-Pointing-Pointer Machining/grinding drastically reduce the SCC resistance of 304L SS in chloride. Black-Right-Pointing-Pointer Machining/grinding make the surface of 304L SS electrochemically much more active. Black-Right-Pointing-Pointer SECM study reveal that preferential dissolution takes place along surface asperities.

  14. Characterization of the deformation and annealing of 304L stainless steel. Final report

    SciTech Connect

    Smith, W.H.

    1994-08-01

    Stainless steel, type 304L, was deformed at room temperature using the two processes of semi-piercing and cold-rolling and then annealed at various temperatures and times. The three metallurgical areas of work hardening, age hardening, and anneal softening were observed and characterized using metallography techniques of macrohardness, optical and transmission electron microscopy, and X-ray diffraction.

  15. Mitigation of Stress Corrosion Cracking Susceptibility of Machined 304L Stainless Steel Through Laser Peening

    NASA Astrophysics Data System (ADS)

    Sundar, R.; Ganesh, P.; Kumar, B. Sunil; Gupta, R. K.; Nagpure, D. C.; Kaul, R.; Ranganathan, K.; Bindra, K. S.; Kain, V.; Oak, S. M.; Singh, Bijendra

    2016-09-01

    The paper describes an experimental study aimed at suppressing stress corrosion cracking susceptibility of machined 304L stainless steel specimens through laser shock peening. The study also evaluates a new approach of oblique laser shock peening to suppress stress corrosion cracking susceptibility of internal surface of type 304L stainless steel tube. The results of the study, performed with an indigenously developed 2.5 J/7 ns Nd:YAG laser, demonstrated that laser shock peening effectively suppresses chloride stress corrosion cracking susceptibility of machined surface of type 304L stainless steel. In the investigated range of incident laser power density (3.2-6.4 GW/cm2), machined specimens peened with power density of 4.5 and 6.4 GW/cm2 displayed lower stress corrosion cracking susceptibility considerably than those treated with 3.2 and 3.6 GW/cm2 in boiling magnesium chloride test. Oblique laser shock peening, performed on machined internal surface of a type 304L stainless steel tube (OD = 111 mm; ID = 101 mm), was successful in introducing residual compressive surface stresses which brought about significant suppression of its stress corrosion cracking susceptibility. The technique of oblique laser shock peening, in spite of its inherent limitations on the length of peened region being limited by tube internal diameter and the need for access from both the sides, presents a simplified approach for peening internal surface of small tubular components.

  16. Experiments for calibration and validation of plasticity and failure material modeling: 304L stainless steel.

    SciTech Connect

    Lee, Kenneth L.; Korellis, John S.; McFadden, Sam X.

    2006-01-01

    Experimental data for material plasticity and failure model calibration and validation were obtained from 304L stainless steel. Model calibration data were taken from smooth tension, notched tension, and compression tests. Model validation data were provided from experiments using thin-walled tube specimens subjected to path dependent combinations of internal pressure, extension, and torsion.

  17. Effect of Harmonic Microstructure on the Corrosion Behavior of SUS304L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Rai, Prabhat K.; Shekhar, S.; Nakatani, M.; Ota, M.; Vajpai, S. K.; Ameyama, K.; Mondal, K.

    2016-12-01

    Corrosion behavior of a harmonic structured SUS304L austenitic stainless steel was examined and compared with nonharmonic structured SUS304L stainless steel and conventional 304 stainless steel in 3.5 pct NaCl solution. The study was performed using linear polarization, potentiodynamic polarization, cyclic polarization, and a salt fog exposure test for 30 days. Characterization was accomplished using a scanning electron microscope, an electron probe microanalyzer, and Raman spectroscopy. Improved pitting corrosion resistance was found in the case of the harmonic structured steel as compared to that of the nonharmonic and the conventional 304 stainless steel. Harmonically distributed fine-grained structure, less porosity, and higher fraction of passive α-FeOOH are attributed to the improvement in corrosion resistance of the harmonic structured steel.

  18. Evaluation of weldment sensitization on Type 304 and 304L stainless steel spent-fuel canisters

    SciTech Connect

    Filippio, A.M.

    1980-01-01

    Sensitization was evaluated on welded Type 304 and 304L stainless steel canisters produced for the Commercial Waste Spent Fuel Packaging Program (CWSFPP) and the Nevada Nuclear Waste Storage Program (NNWSP). The canister weldments which were made under conditions having the greatest potential for causing sensitization were examined using metallographic and corrosion test practices described in Specification ASTM A-262, and also by exposure to hypothetical conditions simulating continuous boiling water immersion at the storage sites. When tested to ASTM A-262, the Type 304 weldments displayed classical evidence of sensitization; i.e., loss of corrosion resistance at heat affected zones, but no evidence of sensitizations was uncovered on the Type 304L weldments. Both the Type 304 and 304L weldments were totally unaffected by exposure for 1500 hours under conditions of continuous boiling water immersion, indicating that the CWSFPP and NNWSP canisters have adequate corrosion resistance for the intended applications.

  19. TESTING OF 304L STAINLESS STEEL IN NITRIC ACID ENVIRONMENTS WITH FLUORIDES AND CHLORIDES

    SciTech Connect

    Mickalonis, J.

    2010-10-04

    Impure radioactive material processed in nitric acid solutions resulted in the presence of chlorides in a dissolver fabricated from 304L stainless steel. An experimental program was conducted to study the effects of chloride in nitric acid/fluoride solutions on the corrosion of 304L stainless steel. The test variables included temperature (80, 95, and 110 C) and the concentrations of nitric acid (6, 12, and 14 M), fluoride (0.01, 0.1, and 0.2 M) and chloride (100, 350, 1000, and 2000 ppm). The impact of welding was also investigated. Results showed that the chloride concentration alone was not a dominant variable affecting the corrosion, but rather the interaction of chloride with fluoride significantly affected corrosion.

  20. Stress corrosion cracking of type 304L stainless steel core shroud welds.

    SciTech Connect

    Chung, H. M.; Park, J.-H.; Sanecki, J. E.; Zaluzec, N. J.; Yu, M. S.; Yang, T. T.

    1999-10-26

    Microstructural analyses by advanced metallographic techniques were conducted on mockup welds and a cracked BWR core shroud weld fabricated from Type 304L stainless steel. heat-affected zones of the shroud weld and mockup shielded-metal-arc welds were free of grain-boundary carbide, martensite, delta ferrite, or Cr depletion near grain boundaries. However, as a result of exposure to welding fumes, the heat-affected zones of the welds were significantly contaminated by fluorine and oxygen which migrate to grain boundaries. Significant oxygen contamination promotes fluorine contamination and suppresses classical thermal sensitization, even in Type 304 steels. Results of slow-strain-rate tensile tests indicate that fluorine exacerbates the susceptibility of irradiated steels to intergranular stress corrosion cracking. These observations, combined with previous reports on the strong influence of weld flux, indicate that oxygen and fluorine contamination and fluorine-catalyzed stress corrosion play a major role in cracking of Type 304L stainless steel core shroud welds.

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

    SciTech Connect

    Antoun, Bonnie R.

    2004-11-01

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

  2. Type 304L stainless steel surface microstructure: Performance in hydride storage and acid cleaning

    SciTech Connect

    Clark, E.A.

    1994-07-01

    The performance of stainless steel as the container in hydride storage bed systems has been evaluated, primarily using scanning electron microscopy. No adverse reaction between Type 304L stainless steel and either LaNi{sub 5{minus}x},Al{sub x}, or palladium supported on Kieselguhr granules (silica) during exposure in hydrogen was found in examination of retired prototype storage bed containers and special compatibility test samples. Intergranular surface ditching, observed on many of the stainless steel surfaces examined, was shown to result from air annealing and acid cleaning of stainless steel during normal fabrication. The ditched air annealed and acid cleaned stainless steel samples were more resistant to subsequent acid attack than vacuum annealed or polished samples without ditches.

  3. Comparison of Stress Corrosion Cracking Susceptibility of Laser Machined and Milled 304 L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Gupta, R. K.; Kumar, Aniruddha; Nagpure, D. C.; Rai, S. K.; Singh, M. K.; Khooha, Ajay; Singh, A. K.; Singh, Amrendra; Tiwari, M. K.; Ganesh, P.; Kaul, R.; Singh, B.

    2016-12-01

    Machining of austenitic stainless steel components is known to introduce significant enhancement in their susceptibility to stress corrosion cracking. The paper compares stress corrosion cracking susceptibility of laser machined 304 L stainless steel specimens with conventionally milled counterpart in chloride environment. With respect to conventionally milled specimens, laser machined specimens displayed more than 12 times longer crack initiation time in accelerated stress corrosion cracking test in boiling magnesium chloride as per ASTM G36. Reduced stress corrosion cracking susceptibility of laser machined surface is attributed to its predominantly ferritic duplex microstructure in which anodic ferrite phase was under compressive stress with respect to cathodic austenite.

  4. Effects of Friction Stir Processing on the Microstructure and Mechanical Properties of Fusion Welded 304L Stainless Steel

    DTIC Science & Technology

    2004-01-01

    Effects of Friction Stir Processing on the Microstructure and Mechanical Properties of Fusion Welded 304L Stainless Steel C.J. Sterling1, T.W...Microstructure and Mechanical Properties of Fusion Welded 304L Stainless Steel 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...Nelson1, C.D. Sorensen1 and M. Posada2 1Department of Mechanical Engineering Brigham Young University 435 CTB Provo, UT, 84602, USA 2Naval Surface

  5. Tritium permeation through characterized films on Type 304L stainless steel

    SciTech Connect

    Kallas, A.J.; Rising, T.L.; Childs, E.L.; Thomas, R.L.

    1987-07-24

    Rocky Flats is looking for an optimum method for surface treating 304L stainless steel to increase its resistance to tritium permeation. Selected surface treatments were applied to 304L samples. One set of samples was shipped to the Rockwell Corporate Science Center for alternate characterization analysis. Another set was sent to Los Alamos National Laboratory for tritium exposure and ion beam spectrographic analysis. The Science Center performed the following analyses: ellipsometry, contact potential, photoelectron emission, surface energy, surface activation, cathodic polarization, electrochemical impedance, and open-circuit potential. Excellent correlation was found between type of treatment and surface activation and electrochemical impedance. Results of the Science Center tests correlated well with actual tritium permeation measurements made at Los Alamos. 8 refs., 8 figs., 1 tab.

  6. Corrosion testing of type 304L stainless steel in tuff groundwater environments

    SciTech Connect

    Westerman, R.E.; Pitman, S.G.; Haberman, J.H.

    1987-11-01

    The stress-corrosion cracking (SCC) resistance of Type 304L stainless steel (SS) to elevated temperatures in tuff rock and tuff groundwater environments was determined under irradiated and nonirradiated conditions using U-bend specimens and slow-strain-rate tests. The steel was tested both in the solution-annealed condition and after sensitization heat treatments. The material was found to be susceptible to SCC in both the solution-annealed and solution-annealed-and-sensitized conditions when exposed to an irradiated crushed tuff rock environment containing air and water vapor at 90{sup 0}C. A similar exposure at 50{sup 0}C did not result in failure after a 25-month test duration. Specimens of sensitized 304 SS conditioned with a variety of sensitization heat treatments resisted failure during a test of 1-year duration in which a nonirradiated environment of tuff rock and groundwater held at 200{sup 0}C was allowed to boil to dryness on a cyclical basis. All specimens of sensitized 304 SS exposed to this environment failed. Slow-strain-rate studies were performed on 304L, 304, and 316L SS specimens. The 304L SS was tested in J-13 well water at 150{sup 0}C, and the 316L SS at 95{sup 0}C. Neither material showed evidence of SCC in these tests. Sensitized 304 SS did exhibit SCC in J-13 well water in tests conducted at 150{sup 0}C. 12 refs., 27 figs., 13 tabs.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  8. Comparison of SCC Behavior of 304L Stainless Steels With and Without Boron Addition in Acidic Chloride Environment

    NASA Astrophysics Data System (ADS)

    Sivai Bharasi, N.; Pujar, M. G.; Nirmal, S.; Mallika, C.; Kamachi Mudali, U.; Angelo, P. C.

    2016-07-01

    The stress corrosion cracking (SCC) behavior of 304L B4 grade borated stainless steel (SS) as well as 304L SS was investigated by constant load and slow strain rate testing (SSRT) techniques. The microstructure, pitting, and SCC behavior of borated SS in the as-received, sensitized, and solution-annealed conditions were analyzed. Potentiodynamic anodic polarization and double loop electrochemical potentiokinetic reactivation (DLEPR) experiments were carried out to find out pitting corrosion resistance and degree of sensitization (DOS). The number of boride particles (composed of Cr, Fe, and B) were highest for the specimen solution annealed at 1423 K/2 h. Solution-annealing treatment at 1423 K/4 h was found to be beneficial in improving the corrosion resistance of borated 304L SS. Although the borated 304L SS exhibited a higher DOS, it showed improved pitting corrosion resistance compared to 304L SS. Constant load experiments revealed the time to failure to be the highest for the specimen solution annealed at 1423 K/4 h. SCC susceptibility index (Iscc) values obtained from SSRT tests were lower for solution-annealed borated 304L SS compared to the as-received and sensitized conditions. The improved SCC resistance of borated 304L SS was attributed not only to the solution-annealing treatment but also the higher stacking fault energy (SFE) value compared to 304L SS.

  9. Quantification of stress history in type 304L stainless steel using positron annihilation spectroscopy

    SciTech Connect

    Walters, Thomas W.; Walters, Leon C.; Schoen, Marco P.; Naidu, D. Subbaram; Dickerson, Charles; Perrenoud, Ben C.

    2011-04-15

    Five Type 304L stainless steel specimens were subjected to incrementally increasing values of plastic strain. At each value of strain, the associated static stress was recorded and the specimen was subjected to positron annihilation spectroscopy (PAS) using the Doppler Broadening method. A calibration curve for the 'S' parameter as a function of stress was developed based on the five specimens. Seven different specimens (blind specimens labeled B1-B7) of 304L stainless steel were subjected to values of stress inducing plastic deformation. The values of stress ranged from 310 to 517 MPa. The seven specimens were subjected to PAS post-loading using the Doppler Broadening method, and the results were compared against the developed curve from the previous five specimens. It was found that a strong correlation exists between the 'S' parameter, stress, and strain up to a strain value of 15%, corresponding to a stress value of 500 MPa, beyond which saturation of the 'S' parameter occurs. Research Highlights: {yields} Specimens were initially in an annealed/recrystallized condition. {yields} Calibration results indicate positron annihilation measurements yield correlation. {yields} Deformation produced by cold work was likely larger than the maximum strain.

  10. Quantification of Stress History in Type 304L Stainless Steel Using Positron Annihilation Spectroscopy

    SciTech Connect

    Thomas W. Walters

    2011-04-01

    Five type 304L stainless steel specimens were subjected to incrementally increasing values of plastic strain. At each value of strain, the associated static stress was recorded and the specimen was subjected to Positron Annihilation Spectroscopy (PAS) using the Doppler Broadening method. A calibration curve for the ‘S’ parameter as a function of stress was developed based on the five specimens. Seven different specimens (blind specimens labeled B1-B7) of 304L stainless steel were subjected to values of stress inducing plastic deformation. The values of stress ranged from 310-517 MPa. The seven specimens were subjected to Positron Annihilation Spectroscopy post loading using the Doppler Broadening method, and the results were compared against the developed curve from the previous five specimens to determine feasibility of applying the curve to materials in order to non-destructively quantify stress history in materials based only on the ‘S’ parameter extracted from the Positron Annihilation Spectroscopy. Results for the calibration set of specimens indicated that calibration development is possible.

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

    SciTech Connect

    Zapp, P.E.

    2001-02-06

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

  12. HYDROGEN EFFECTS ON STRAIN-INDUCED MARTENSITE FORMATION IN TYPE 304L STAINLESS STEEL

    SciTech Connect

    Morgan, M; Ps Lam, P

    2008-12-11

    Unstable austenitic stainless steels undergo a strain-induced martensite transformation. The effect of hydrogen on this transformation is not well understood. Some researchers believe that hydrogen makes the transformation to martensite more difficult because hydrogen is an austenite stabilizer. Others believe that hydrogen has little or no effect at all on the transformation and claim that the transformation is simply a function of strain and temperature. Still other researchers believe that hydrogen should increase the ability of the metal to transform due to hydrogen-enhanced dislocation mobility and slip planarity. While the role of hydrogen on the martensite transformation is still debated, it has been experimentally verified that this transformation does occur in hydrogen-charged materials. What is the effect of strain-induced martensite on hydrogen embrittlement? Martensite near crack-tips or other highly strained regions could provide much higher hydrogen diffusivity and allow for quicker hydrogen concentration. Martensite may be more intrinsically brittle than austenite and has been shown to be severely embrittled by hydrogen. However, it does not appear to be a necessary condition for embrittlement since Type 21-6-9 stainless steel is more stable than Type 304L stainless steel but susceptible to hydrogen embrittlement. In this study, the effect of hydrogen on strain-induced martensite formation in Type 304L stainless steel was investigated by monitoring the formation of martensite during tensile tests of as-received and hydrogen-charged samples and metallographically examining specimens from interrupted tensile tests after increasing levels of strain. The effect of hydrogen on the fracture mechanisms was also studied by examining the fracture features of as-received and hydrogen-charged specimens and relating them to the stress-strain behavior.

  13. Microstructural Characterization of 6061 Aluminum to 304L Stainless Steel Inertia Welds

    SciTech Connect

    Dunn, K.A.

    1999-09-29

    'Microstructural characterization of 6061-T6 aluminum-to-Type 304L stainless steel inertia welds provided a technical basis to conclude that transition joints fabricated from such welds should satisfactorily contain helium/hydrogen gas mixtures. This conclusion is based on the lack of semi-continuous alignments of particles and/or inclusions at, or near, the aluminum-to-stainless steel interface. These dissimilar metal transition joints play a key role in the operation of an accelerator driven, spallation neutron source designed for the production of tritium. The Accelerator Production of Tritium system will produce tritium through neutron interactions with 3He gas contained in water-cooled, 6061-T6 aluminum pressure tubes. Current design concepts include thousands of thin-walled pressure tubes distributed throughout a number of aluminum-clad, lead-filled, blanket modules. The aluminum pressure tubes are connected to a tritium extraction and purification system through a stainless steel manifold. The transition from aluminum to stainless steel is made via transition joints machined from the aluminum-to-stainless steel inertia welds. The paper describes the baseline microstructural characterization of the welds, including optical, scanning and transmission electron microscopy and uses that characterization to evaluate potential gas leakage across the weld.'

  14. Effect of tin addition on the microstructure development and corrosion resistance of sintered 304L stainless steels

    SciTech Connect

    Wang, W.F.

    1999-12-01

    The effect of tin powder addition on the microstructure development during sintering and corrosion resistance of the 304L-Sn metallurgical system was investigated. Specimens containing 1 to 4 wt% Sn were sintered in hydrogen at temperatures ranging from 800 to 1,300 C. During sintering at temperatures below 1,000 C, most of the liquid phase was retained at the site originally occupied by the tin powder. At temperatures above 1,050 C, the tin-base liquid phase spread and uniformly distributed among the 304L solid particles. Adding tin powder and the resultant liquid phase led 304L powder compacts to expand during sintering. An immersion test in 1 M H{sub 2}SO{sub 4} and metallographic observation showed that pitting always initiated at the spots with lower tin content, and the tin atom enrichment had the beneficial effect of improving the corrosion resistance of sintered 304L stainless steels.

  15. Thermal Stability Study of Ultrafine Grained 304L Stainless Steel Produced by Martensitic Process

    NASA Astrophysics Data System (ADS)

    Sabooni, S.; Karimzadeh, F.; Enayati, M. H.

    2014-05-01

    An ultrafine grain 304L stainless steel with average grain size of about 650 nm was produced by martensitic process. 10 mm as-received sheets were 80% cold rolled in the temperature of -15 °C and then annealed at 700 °C for 300 min to obtain ultrafine grained microstructure. The results showed that the ultrafine grained 304L steel has yield strength of 720 MPa, tensile strength of about 920 MPa, and total elongation of 47% which is about twice that of coarse grain structure. The effect of annealing temperature (750-900 °C) on the grain growth kinetics was modeled by isothermal kinetics equation which resulted in the grain growth exponent ( n) and activation energy for grain growth of 4.8 and 455 KJ/mol, respectively. This activation energy was also compared with those for other austenitic steels to better understanding of the nature of grain growth and atoms mobility during annealing. It was found that activation energy for grain growth is about twice higher than self-diffusion activation energy of austenite that is related to the Zener pinning effects of the second phase particles.

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

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

    DOE PAGES

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

    2015-11-14

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

  18. Grain boundary character modification employing thermo-mechanical processing in type 304L stainless steel

    NASA Astrophysics Data System (ADS)

    Pradhan, S. K.; Mandal, S.

    2016-02-01

    Grain boundary engineering (GBE) approach has been employed to modify the boundaries character of a type 304L stainless steel through thermo-mechanical processing (TMP) route, which combined a low level of cold deformation (5, 10 and 15%) followed by annealing at 1173K and 1273K for 1hour. Employing Electron Back Scatter Diffraction based Orientation Imaging Microscopy, the fraction and distribution of low ∑ CSL boundaries (∑≤ 29) and its effect on random high-angle grain boundaries connectivity and triple junction distribution of as-received (AR) and GBE specimens were evaluated. It was possible to increase the fraction of low ∑ CSL boundaries up to 75% following GBE treatment (as compared to 50% in AR specimen). The GBE specimens also contained maximum number of percolation resistant triple junctions which could render better resistance against percolation related phenomena.

  19. Atmospheric pitting corrosion of 304L stainless steel: the role of highly concentrated chloride solutions.

    PubMed

    Street, Steven R; Mi, Na; Cook, Angus J M C; Mohammed-Ali, Haval B; Guo, Liya; Rayment, Trevor; Davenport, Alison J

    2015-01-01

    The morphology of atmospheric pitting corrosion in 304L stainless steel plate was analysed using MgCl(2) droplets in relation to changes in relative humidity (RH) and chloride deposition density (CDD). It was found that highly reproducible morphologies occur that are distinct at different RH. Pitting at higher concentrations, i.e. lower RH, resulted in satellite pits forming around the perimeter of wide shallow dish regions. At higher RH, these satellite pits did not form and instead spiral attack into the shallow region was observed. Increasing CDD at saturation resulted in a very broad-mouthed pitting attack within the shallow dish region. Large data sets were used to find trends in pit size and morphology in what is essentially a heterogeneous alloy. Electrochemical experiments on 304 stainless steel wires in highly saturated solutions showed that the passive current density increased significantly above 3 M MgCl(2) and the breakdown pitting potential dropped as the concentration increased. It is proposed that the shallow dish regions grow via enhanced dissolution of the passive film, whereas satellite pits and a spiral attack take place with active dissolution of bare metal surfaces.

  20. HYDROGEN EFFECTS ON THE BURST PROPERTIES OF TYPE 304L STAINLESS STEEL FLAWED VESSELS

    SciTech Connect

    Morgan, M; Monica Hall, M; Ps Lam, P; Dean Thompson, D

    2008-03-27

    The effect of hydrogen on the burst properties Type 304L stainless steel vessels was investigated. The purpose of the study was to compare the burst properties of hydrogen-exposed stainless steel vessels burst with different media: water, helium gas, or deuterium gas. A second purpose of the tests was to provide data for the development of a predictive finite-element model. The burst tests were conducted on hydrogen-exposed and unexposed axially-flawed cylindrical vessels. The results indicate that samples burst pneumatically had lower volume ductility than those tested hydraulically. Deuterium gas tests had slightly lower ductility than helium gas tests. Burst pressures were not affected by burst media. Hydrogen-charged samples had lower volume ductility and slightly higher burst pressures than uncharged samples. Samples burst with deuterium gas fractured by quasi-cleavage near the inside wall. The results of the tests were used to improve a previously developed predictive finite-element model. The results show that predicting burst behavior requires as a material input the effect of hydrogen on the plastic strain to fracture from tensile tests. The burst test model shows that a reduction in the plastic strain to fracture of the material will result in lower volume ductility without a reduction in burst pressure which is in agreement with the burst results.

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-05-01

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

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

    DOE PAGES

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

    2015-01-15

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

  4. Irradiation assisted stress corrosion cracking of controlled purity 304L stainless steels

    NASA Astrophysics Data System (ADS)

    Cookson, J. M.; Carter, R. D.; Damcott, D. L.; Atzmon, M.; Was, G. S.

    1993-06-01

    The effect of chromium, phosphorus, silicon and sulfur on the stress corrosion cracking of 304L stainless steel in CERT tests in high purity water or argon at 288°C following irradiation with 3.4 MeV protons at 400°C to 1 dpa, has been investigated using ultrahigh purity alloys (UHP) with controlled impurity additions. Grain boundary segregation of phosphorus or silicon due to proton irradiation was quantified using both Auger electron spectroscopy and scanning transmission electron microscopy, and the alloys with impurity element additions were observed to have greater grain boundary chromium depletion and nickel enrichment than the UHP alloy. The UHP alloy suffered severe cracking in CERT tests in water. Less cracking was found after CERT test of irradiated UHP+Por UHP+Si alloys, despite greater chromium depletion. This suggests a mitigating effect of phosphorus and silicon at grain boundaries. No cracking was found in argon tests, eliminating a purely mechanical embrittlement mechanism, but not eliminating a contribution from radiation hardening. Implanted hydrogen was not a factor in the intergranular cracking found.

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

    NASA Astrophysics Data System (ADS)

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

    2017-09-01

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

  6. High temperature oxidation behavior of AISI 304L stainless steel-Effect of surface working operations

    NASA Astrophysics Data System (ADS)

    Ghosh, Swati; Kumar, M. Kiran; Kain, Vivekanand

    2013-01-01

    The oxidation behavior of grade 304L stainless steel (SS) subjected to different surface finishing (machining and grinding) operations was followed in situ by contact electric resistance (CER) and electrochemical impedance spectroscopy (EIS) measurements using controlled distance electrochemistry (CDE) technique in high purity water (conductivity < 0.1 μS cm-1) at 300 °C and 10 MPa in an autoclave connected to a recirculation loop system. The results highlight the distinct differences in the oxidation behavior of surface worked material as compared to solution annealed material in terms of specific resistivity and low frequency Warburg impedance. The resultant oxide layer was characterized for (a) elemental analyses by glow discharge optical emission spectroscopy (GDOES) and (b) morphology by scanning electron microscopy (SEM). Oxide layers with higher specific resistivity and chromium content were formed in case of machined and ground conditions. Presence of an additional ionic transport process has also been identified for the ground condition at the metal/oxide interface. These differences in electrochemical properties and distinct morphological features of the oxide layer as a result of surface working were attributed to the prevalence of heavily fragmented grain structure and presence of martensite.

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

    SciTech Connect

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

    2015-01-15

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

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

    NASA Astrophysics Data System (ADS)

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

    1994-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    PubMed

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

    2015-01-15

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

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

    PubMed Central

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

    2015-01-01

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

  12. Thermomechanical history measurements on Type 304L stainless steel pipe girth welds

    SciTech Connect

    Li, Ming; Atteridge, D.G.; Anderson, W.E.; Turpin, R.; West, S.L.

    1993-12-31

    Thermal and strain histories were recorded for three 40-cm-diameter (16 inch), Type 304L stainless steel (SS), schedule 40 (1.27 cm thickness) pipe girth welds. Two weld groove preparations were standard V grooves while the third was a narrow groove configuration. The welding parameters for the three pipe welds simulated expected field practice as closely as possible. The narrow gap weld was completed in four continuous passes while the other two welds required six and nine (discontinuous) passes, due to the use of different weld wire diameters. Thermomechanical history measurements were taken on the inner counterbore surface, encompassing the weld centerline and heat-affected zone (HAZ), as well as 10 cm of inner counterbore surface on either side of the weld centerline; a total of 47 data acquisition instruments were used for each weld. These instruments monitored: (1) weld shrinkages parallel to the pipe axis; (2) surface temperatures; (3) surface strains parallel to weld centerline; and (4) radial deformations. Results show that the weld and HAZ experienced cyclic deformation in the radial direction during welding, indicating that the final residual stress distribution in multi-pass pipe weldments is not axisymmetric. Measured radial and axial deformations were smaller for the narrow gap groove than for the standard V grooves, suggesting that the narrow gap groove weldment may have lower residual stress levels than the standard V groove weldments. This study provides the experimental database and a guideline for further computational modeling work.

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

    SciTech Connect

    Sahri, M. I.; Othman, N. K.; Samsu, Z.; Daud, A. R.

    2014-09-03

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

  14. An experimental analysis of temperature and stress fields in girth welded 304L stainless steel pipes

    SciTech Connect

    Li, M.; Atteridge, D.G.; Anderson, W.E.; Hubbard, C.R.; Spooner, S.

    1996-12-31

    The thermal and deformation/strain histories were measured by a computer data acquisition system for three 406-mm-diameter, Type 304L stainless steel (SS), schedule 40 (12.7 mm thickness) pipe girth welds. Two welds were standard V groove preparations and completed in six and nine (discontinuous) passes with multiple start-stop positions, while the third one was a narrow groove configuration and finished with four continuous passes with one start-stop position. The thermomechanical history measurements were taken on the pipe inner surface, encompassing the weld centerline (WCL) and heat-affected zone; a total of 47 data acquisition instruments were used for each weld to monitor weld shrinkages, surface temperatures, surface strains, and radial deformations. The experimental data give the following general conclusions: (1) the temperature profiles in the two V groove weldments are, in general, axisymmetric, while the temperature profile in the narrow gap groove weldment is axisymmetric in locations far from WCL, but is not axisymmetric in locations near start-stop position; (2) the strain/deformation histories are controlled by the thermal histories with the final strain/deformation value largely determined by the last one or two passes of welding; (3) the strain/deformation profile in the weldment is not axisymmetric suggesting that the residual stress is not axisymmetrically distributed; (4) the four-pass narrow gap weldment experienced the fewest time and temperature cycles during welding, and has the lowest level of radial deformation among the three pipe weldments indicating that the narrow gap weldment would have the lowest overall residual stress level among the three pipe weldments. Residual stress measurements on the inner surface of four-pass pipe weldment were performed using the neutron diffraction (ND) technique. The ND results show that a tensile zone exists on the pipe inner surface and in the weld and its heat-affected zone (HAZ) area.

  15. NIOBIUM-CLAD 304L STAINLESS STEEL PEMFC BIPOLAR PLATE MATERIAL: TENSILE AND BEND PROPERTIES

    SciTech Connect

    Hong, Sung-tae; Weil, K. Scott

    2007-06-01

    Niobium (Nb)-clad 304L stainless steel (SS) is currently under consideration for use as a bipolar plate material in polymer electrolyte membrane fuel cell (PEMFC) stacks. Because metal bipolar plates will likely be formed by stamping, the sheet metal properties of this material were characterized in both the as-rolled and an optimized annealed condition via a series of bend and quasi-static tensile tests. Results from tensile testing demonstrate that annealing significantly softens and thereby improves the ductility of the material. Bend test results indicate that springback is nearly independent of the bend direction relative to rolling direction for both the as-rolled and annealed conditions. In the as-rolled condition, springback is also nearly independent of specimen orientation (i.e. whether the cladding layer is on the inside or outside of the bend). However in the annealed condition, springback does depend on the cladding orientation relative to bending and was found in all cases to be substantially lower than that observed in the as-rolled condition. Microstructural analysis of the specimens indicates that two failure conditions can potentially arise, dependent on the thermomechanical condition of the material. In the as-rolled condition, failure initiates via fracture through the Nb cladding. In the annealed specimens, failure can occur by brittle fracture of an interfacial intermetallic layer that forms during the annealing treatment. This generates a series of crack-induced pores along the interface between the Nb cladding and the SS core, which eventually leads to ductile failure of the Nb cladding via localized necking. However the conditions required for this phenomenon to take place are fairly extreme and can be readily avoided in practice. In general, the results suggest that to achieve acceptable stamping tolerances, the material should be annealed prior to forming and the bipolar plate flow channel pattern should be designed such that extreme

  16. Effect of pre-strain on mechanical properties and deformation induced transformation of 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Zulfi, Fahri R.; Korda, Akhmad A.

    2016-08-01

    Effect of pre-strain on mechanical properties and deformation induced phase transformation of 304 stainless steel under tensile deformation has been studied. Pre-strain with the variation percentage of deformation was applied to the tensile test specimens. Tensile and hardness testing were carried out after pre-strain to study the mechanical properties change. Deformation induced phase transformation was investigated by using X-ray diffraction and optical microscope. XRD study indicates that metastable austenite transforms to martensite due to deformation. The martensite volume fraction increases with the increase in percentage of deformation. The increase in strength and hardness were associated with an increase in the volume fraction of martensite.

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

    NASA Astrophysics Data System (ADS)

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

    2017-05-01

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

  18. Tensile Stress-Strain Results for 304L and 316L Stainless-Steel Plate at Temperature

    SciTech Connect

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

    2007-07-01

    The Idaho National Laboratory (INL) is conducting moderate strain rate (10 to 200 per second) research on stainless steel materials in support of the Department of Energy’s (DOE) National Spent Nuclear Fuel Program (NSNFP). For this research, strain rate effects are characterized by comparison to quasi-static tensile test results. Considerable tensile testing has been conducted resulting in the generation of a large amount of basic material data expressed as engineering and true stress-strain curves. The purpose of this paper is to present the results of quasi-static tensile testing of 304/304L and 316/316L stainless steels in order to add to the existing data pool for these materials and make the data more readily available to other researchers, engineers, and interested parties. Standard tensile testing of round specimens in accordance with ASTM procedure A 370-03a were conducted on 304L and 316L stainless-steel plate materials at temperatures ranging from -20 °F to 600 °F. Two plate thicknesses, eight material heats, and both base and weld metal were tested. Material yield strength, Young’s modulus, ultimate strength, ultimate strain, failure strength and failure strain were determined, engineering and true stress-strain curves to failure were developed, and comparisons to ASME Code minimums were made. The procedures used during testing and the typical results obtained are described in this paper.

  19. Microstructural Study Of Fusion Welds in 304L and 21Cr-6Ni-9Mn Stainless Steels (U)

    SciTech Connect

    MICHAEL, TOSTEN

    2005-03-01

    Light-optical and transmission electron microscopy (TEM) have been employed to characterize the microstructures of a series of fusion welds made on 304L and 21-6-9 stainless steels. The materials investigated in this study included high-energy-rate-forged 304L, conventionally forged 21-6-9, and 304L weld critical plate (higher ferrite potential). The weld critical plate contained an electron beam weld (no filler wire) while other specimens were welded with various combinations of 308L, 309L modified (MOD) and 312 MOD stainless steel filler wires to produce samples with a range of delta ferrite contents (4 to 33 percent) in the resulting welds. TEM specimens were prepared from broken arc-shaped, mechanical property test specimens that had been used to measure fracture toughness of the fusion welds. Specimens were prepared from regions of the weld heat-affected zones as well as from areas within the weld metal, including areas close to the fracture surface (plastically deformed regions). The observed microstructures varied according to the amount of ferrite in each weld. At the lowest ferrite levels the microstructure consisted of austenite and skeletal ferrite with austenite being the majority (matrix) phase. At intermediate levels of ferrite, lathy austenite/ferrite was observed and the ferrite became continuous throughout the specimens examined. In the weld with the most ferrite, many austenite morphologies were observed and ferrite was the matrix phase. Closest to the fracture surface an increase in dislocation density in both the ferrite and austenite were observed in all welds. Deformation twinning was also observed in the austenite. Many of the welds contained a large number of non-metallic inclusions (oxide particles) which most likely originated from impurities in the weld wires.

  20. Experimental Investigations on Anisotropic Evolution of 304 Stainless Sheets under Tensile Pre-Strains

    NASA Astrophysics Data System (ADS)

    Teng, Lai; Guo, Cheng

    2011-08-01

    The anisotropic evolution of cold rolled 304 stainless steel sheets under pre-strains is investigated experimentally. Uni-axial tensile yield stress and r-value are measured in experiments to represent the anisotropy. The tensile pre-strains under plane stress are achieved by cutting large specimens into small one at different angles to rolling direction. Then the uni-axial tensile tests are performed on the small specimens to investigate the anisotropic evolution. It is found that the yield stress increases with the increase of the pre-strains and decreases with the increase of the angles. However, the changes of r-value are hardly affected by the pre-strains, the small changes of r-value show that the material may remember the rolling direction even after the pre-strains. The sigmoidal shape can be observed in the tensile curves, and its shape depends on the pre-strains and angles. The change of hardening rate can be divided into three stages, and is the most significant at 90° to the rolling direction in the three stages, at the same time the pre-strains cause noncoincidence of the hardening rate curves at the same angle. Moreover, the hardening rate depends on the directions of tensile loading. Second derivative of the hardening rate also can be divided into three stages, and the differences of three stages may mainly be controlled by the different volume fraction of martensite.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  2. Examination of irradiated 304L stainless steel to 6061-T6 aluminum inertia welded transition joints after irradiation in a spallation neutron

    SciTech Connect

    Dunn, K.A.

    2000-04-28

    The Savannah River Technology Center (SRTC) designed and fabricated tritium target/blanket assemblies which were irradiated for six months at the Los Alamos Neutron Science Center (LANSCE). Cooling water was supplied to the assemblies through 1 inch diameter 304L Stainless Steel (SS) tubing. To attach the 304L SS tubing to the modules a 304L SS to 6061-T6 Aluminum (Al) inertia welded transition joint was used. These SS/Al inertia weld transition joints simulate expected transition joints in the Accelerator Production of Tritium (APT) Target/Blanket where as many as a thousand SS/Al weld transition joints will be used. Materials compatibility between the 304L SS and the 6061-T6 Al in the spallation neutron environment is a major concern as well as the corrosion associated with the cooling water flowing through the piping. The irradiated inertia weld examination will be discussed.

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

    SciTech Connect

    Lawrence, Samantha Kay; Adams, David P.; Bahr, David F.; Moody, Neville R.

    2015-11-14

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

  4. Effects of Low Temperature on Hydrogen-Assisted Crack Growth in Forged 304L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Jackson, Heather; San Marchi, Chris; Balch, Dorian; Somerday, Brian; Michael, Joseph

    2016-08-01

    The objective of this study was to evaluate effects of low temperature on hydrogen-assisted crack propagation in forged 304L austenitic stainless steel. Fracture initiation toughness and crack-growth resistance curves were measured using fracture mechanics specimens that were thermally precharged with 140 wppm hydrogen and tested at 293 K or 223 K (20 °C or -50 °C). Fracture initiation toughness for hydrogen-precharged forgings decreased by at least 50 to 80 pct relative to non-charged forgings. With hydrogen, low-temperature fracture initiation toughness decreased by 35 to 50 pct relative to room-temperature toughness. Crack growth without hydrogen at both temperatures was microstructure-independent and indistinguishable from blunting, while with hydrogen microcracks formed by growth and coalescence of microvoids. Initiation of microvoids in the presence of hydrogen occurred where localized deformation bands intersected grain boundaries and other deformation bands. Low temperature additionally promoted fracture initiation at annealing twin boundaries in the presence of hydrogen, which competed with deformation band intersections and grain boundaries as sites of microvoid formation and fracture initiation. A common ingredient for fracture initiation was stress concentration that arose from the intersection of deformation bands with these microstructural obstacles. The localized deformation responsible for producing stress concentrations at obstacles was intensified by low temperature and hydrogen. Crack orientation and forging strength were found to have a minor effect on fracture initiation toughness of hydrogen-supersaturated 304L forgings.

  5. Microstructure and Mechanical Properties of Plasma Arc Brazed AISI 304L Stainless Steel and Galvanized Steel Plates

    NASA Astrophysics Data System (ADS)

    Jin, Yajuan; Li, Ruifeng; Yu, Zhishui; Wang, Yu

    2016-04-01

    Plasma arc brazing is used to join the AISI 304L stainless steel and galvanized steel plate butt joints with the CuSi3Mn1 filler wire. The effect of parameters on weld surface appearance, interfacial microstructure, and composition distribution in the joint was studied. The microhardness and mechanical tests were conducted to determine the mechanical properties of the welded specimens. The results indicated that good appearance, bead shape, and sufficient metallurgical bonding could be obtained when the brazing process was performed with a wire feeding speed of 0.8 m/min, plasma gas flow rate of 3.0 l/min, welding current of 100 A, and welding speed of 27 cm/min. During plasma arc brazing process, the top corner of the stainless steel and galvanized steel plate were heated and melted, and the melted quantity of stainless steel was much more than that of the galvanized steel due to the thermal conductivity coefficient difference between the dissimilar materials. The microhardness test results shows that the microhardness value gradually increased from the side of the galvanized steel to the stainless steel in the joint, and it is good for improving the mechanical properties of joint. The tensile strength was a little higher than that of the brazing filler, and the fracture position of weld joint was at the base metal of galvanized steel plate.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  8. Impact properties of 304L stainless steel GTAW joints evaluated by high strain rate of compression tests

    NASA Astrophysics Data System (ADS)

    Lee, Woei-Shyan; Lin, Chi-Feng; Liu, Chen-Yang; Tzeng, Fan-Tzung

    2004-12-01

    This paper presents an investigation into the high velocity impact of 304L stainless steel gas tungsten arc welded (GTAW) joints at strain rates between 10-3 and 7.5 × 103 s-1 using a compressive split-Hopkinson bar. The results show that the impact properties and fracture characteristics of the tested weldments depend strongly on applied strain rate. This rate-dependent behavior is in good agreement with model predictions using the hybrid Zerilli-Armstrong constitutive law. It is determined that the tested weldments fail as a result of adiabatic shearing. The fracture surfaces of the fusion zone and base metal regions are characterized by the presence of elongated dimples. The variation in the observed dimple features with strain rate is consistent with the results of the impact stress-strain curves.

  9. Effect of Composition on the Formation of Delta Ferrite in 304L Austenitic Stainless Steels During Hot Deformation

    NASA Astrophysics Data System (ADS)

    Soleymani, S.; Ojo, O. A.; Richards, N.

    2015-01-01

    Four different AISI 304L austenitic stainless steels with chromium equivalent-to-nickel equivalent (Creq/Nieq) ratios of 1.57, 1.59, 1.62, and 1.81 were chosen for this study. The influence of chemical composition on solid-state formation of delta ferrite phase during hot deformation was investigated. Compression tests were performed at temperature, strain, and strain rate ranges of 1200 to 1300 °C, 10 to 70%, and 0.1 to 10 s-1, respectively. Increasing the temperature, strain, and strain rate led to increased formation of delta ferrite. The results show that the formation of delta ferrite during hot deformation is also strongly dependent on chemical composition. The higher the Creq/Nieq ratio, the higher the tendency for the formation of delta ferrite. The observed behavior may be attributed to plastic deformation-induced formation of crystallographic defects such as dislocations affecting the diffusion rate.

  10. Some aspects of thermomechanical fatigue of AISI 304L stainless steel; Part 1: Creep-fatigue damage

    SciTech Connect

    Zauter, R. ); Christ, H.J. . Inst. of Materials Technology); Mughrabi, H. . Inst. for Materials Science)

    1994-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Sejč, Pavol; Kubíček, Rastislav

    2011-12-01

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

  13. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    SciTech Connect

    Sindelar, R.L.; Caskey, G.R. Jr.

    1991-12-01

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950`s are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

  14. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    SciTech Connect

    Sindelar, R.L.; Caskey, G.R. Jr.

    1991-12-01

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950's are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

  15. A Study on Deformation Behavior of 304L Stainless Steel During and After Plate Rolling at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Pourabdollah, P.; Serajzadeh, S.

    2016-12-01

    In this work, microstructural evolutions and mechanical properties of AISI 304L stainless steel were studied after rolling operations at elevated temperatures. Rolling experiments were conducted under warm and hot rolling conditions in the range of 600-1000 °C employing different reductions. Then, the developed microstructures and the mechanical properties of the steel were evaluated by means of uniaxial tensile testing, metallographic observations, and x-ray diffraction method. Besides, two-dimensional finite element analysis coupled with artificial neural network modeling was developed to assess thermo-mechanical behavior of the steel during and after rolling. The results show that inhomogeneities in strain and temperature distributions are reduced under warm rolling conditions. Static recrystallization can be operative under hot rolling conditions and relatively low reduction, i.e., reduction of 25%. However, for the case of higher reductions, the rate of recrystallization decreases considerably owing to severe temperature drop in the plate being rolled. Furthermore, the rolled plates show negative strain rate sensitivity while this phenomenon is affected by the rolling temperature.

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

    NASA Astrophysics Data System (ADS)

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

    2017-07-01

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

  17. Effect of forging strain rate and deformation temperature on the mechanical properties of warm-worked 304L stainless steel

    SciTech Connect

    Switzner, N. T.; Van Tyne, C. J.; Mataya, M. C.

    2010-01-25

    Stainless steel 304L forgings were produced with four different types of production forging equipment – hydraulic press, mechanical press, screw press, and high-energy rate forging (HERF). Each machine imparted a different nominal strain rate during the deformation. The final forgings were done at the warm working (low hot working) temperatures of 816 °C, 843°C, and 871°C. The objectives of the study were to characterize and understand the effect of industrial strain rates (i.e. processing equipment), and deformation temperature on the mechanical properties for the final component. Some of the components were produced with an anneal prior to the final forging while others were deformed without the anneal. The results indicate that lower strain rates produced lower strength and higher ductility components, but the lower strain rate processes were more sensitive to deformation temperature variation and resulted in more within-part property variation. The highest strain rate process, HERF, resulted in slightly lower yield strength due to internal heating. Lower processing temperatures increased strength, decreased ductility but decreased within-part property variation. The anneal prior to the final forging produced a decrease in strength, a small increase in ductility, and a small decrease of within-part property variation.

  18. A Study on Deformation Behavior of 304L Stainless Steel During and After Plate Rolling at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Pourabdollah, P.; Serajzadeh, S.

    2017-02-01

    In this work, microstructural evolutions and mechanical properties of AISI 304L stainless steel were studied after rolling operations at elevated temperatures. Rolling experiments were conducted under warm and hot rolling conditions in the range of 600-1000 °C employing different reductions. Then, the developed microstructures and the mechanical properties of the steel were evaluated by means of uniaxial tensile testing, metallographic observations, and x-ray diffraction method. Besides, two-dimensional finite element analysis coupled with artificial neural network modeling was developed to assess thermo-mechanical behavior of the steel during and after rolling. The results show that inhomogeneities in strain and temperature distributions are reduced under warm rolling conditions. Static recrystallization can be operative under hot rolling conditions and relatively low reduction, i.e., reduction of 25%. However, for the case of higher reductions, the rate of recrystallization decreases considerably owing to severe temperature drop in the plate being rolled. Furthermore, the rolled plates show negative strain rate sensitivity while this phenomenon is affected by the rolling temperature.

  19. Evaluation of stress corrosion cracking of irradiated 304L stainless steel in PWR environment using heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Gupta, J.; Hure, J.; Tanguy, B.; Laffont, L.; Lafont, M.-C.; Andrieu, E.

    2016-08-01

    IASCC has been a major concern regarding the structural and functional integrity of core internals of PWR's, especially baffle-to-former bolts. Despite numerous studies over the past few decades, additional evaluation of the parameters influencing IASCC is still needed for an accurate understanding and modeling of this phenomenon. In this study, Fe irradiation at 450 °C was used to study the cracking susceptibility of 304 L austenitic stainless steel. After 10 MeV Fe irradiation to 5 dpa, irradiation-induced damage in the microstructure was characterized and quantified along with nano-hardness measurements. After 4% plastic strain in a PWR environment, quantitative information on the degree of strain localization, as determined by slip-line spacing, was obtained using SEM. Fe-irradiated material strained to 4% in a PWR environment exhibited crack initiation sites that were similar to those that occur in neutron- and proton-irradiated materials, which suggests that Fe irradiation may be a representative means for studying IASCC susceptibility. Fe-irradiated material subjected to 4% plastic strain in an inert argon environment did not exhibit any cracking, which suggests that localized deformation is not in itself sufficient for initiating cracking for the irradiation conditions used in this study.

  20. Effect of texture on corrosion behavior of AISI 304L stainless steel

    SciTech Connect

    Ravi Kumar, B. . E-mail: ravik@nmlindia.org; Singh, Raghuvir; Mahato, Bhupeshwar; De, P.K.; Bandyopadhyay, N.R.; Bhattacharya, D.K.

    2005-02-15

    Electrochemical behavior of austenitic AISI 304 stainless steel in two different solutions is presented here. Effect of cold rolling conditions on corrosion behavior of the steel is studied with respect to strain-induced {alpha}'-martensite phase, residual stress, and texture of both the austenite and {alpha}'-martensite phases. The annealed steel plate has been unidirectionally cold, rolled-up to 90% reductions. X-ray diffraction (XRD) technique has been employed to quantify the volume fractions of austenite and martensite phases and to study the textural development in the steel in rolled conditions. The presence of close pack crystallographic planes parallel to the specimen surface found to improve the corrosion properties.

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  2. Flux effect on the ion-beam nitriding of austenitic stainless-steel AISI 304L

    SciTech Connect

    Abrasonis, G.; Riviere, J.P.; Templier, C.; Pranevicius, L.; Barradas, N.P.

    2005-06-15

    The effect of flux and Ar pretreatment during ion-beam nitriding of austenitic stainless steel is investigated. The ion energy and temperature were 1.2 keV and 400 deg. C, respectively, the ion current densities were 0.5, 0.67, and 0.83 mA cm{sup -2}. The nitrogen distribution profiles were measured using nuclear reaction analysis. The obtained nitrogen distribution profiles were analyzed by the means of the nitrided layer thickness evolution due to sputtering and diffusion and the model of trapping-detrapping. Both approaches could fit well the experimental results, however, different diffusion coefficients have to be assumed for each current density. In addition, the diffusion coefficients are higher for higher current densities. On the other hand, it is shown that the pretreatment with Ar-ion beam at nitriding temperatures produces only a thermal effect without any other influence on the following nitrogen diffusion. The results are discussed in relation with surface and temperature effects and atomic transport mechanisms.

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

    SciTech Connect

    Unnikrishnan, Rahul; Idury, K.S.N. Satish; Ismail, T.P.; Bhadauria, Alok; Shekhawat, S.K.; Khatirkar, Rajesh K.; Sapate, Sanjay G.

    2014-07-01

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

  4. A transmission electron microscopy evaluation of solid-state upset welds in Type 304L stainless steel

    SciTech Connect

    Tosten, M.H.

    1995-09-08

    Transmission electron microscopy (TEM) was used to characterize the microstructures at and near the weld interface in upset welded Type 304L stainless steel test samples. Two sample configurations were examined in this study; upset welded cylinders prepared using a commercial resistance welder and cylindrical shaped samples welded in a Gleeble 1500 thermomechanical simulation device. The Gleeble samples evaluated were welded at 800 C, 900 C and 1,200 C with a 0.5 cm weld upset. The base microstructure of the samples varied with weld temperature. The lower temperature specimens contained a large free-dislocation density and distinct dislocation cells. The higher temperature specimens contained well-developed subgrains and a much lower free-dislocation density. The microstructure of the upset welded samples most closely resembled the 1,200 C Gleeble sample. No distinct bond line was observed by TEM in any of the specimens, i.e., diffusion and grain growth occurred across all weld interfaces. However, weld interfaces in both specimen configurations were characterized by the presence of 50--300 nm diameter particles spaced between 300 and 1,300 nm apart. Through the use of electron diffraction analysis and X-ray microanalysis two precipitate types were identified in both specimen configurations. A crystalline phase very similar to Mn{sub 1.5}Cr{sub 1.5}O{sub 4} and an amorphous phase enriched mainly in Si and Al were observed. Surface oxides and/or internal impurities may be sources for these precipitates. Future work will include a controlled study designed to determine the origin of the interface precipitates.

  5. Investigation of micro-structure and micro-hardness properties of 304L stainless steel treated in a hot cathode arc discharge plasma

    SciTech Connect

    Malik, Hitendra K.; Singh, Omveer; Dahiya, Raj P.

    2015-08-28

    We have established a hot cathode arc discharge plasma system, where different stainless steel samples can be treated by monitoring the plasma parameters and nitriding parameters independently. In the present work, a mixture of 70% N{sub 2} and 30% H{sub 2} gases was fed into the plasma chamber and the treatment time and substrate temperature were optimized for treating 304L Stainless Steel samples. Various physical techniques such as x-ray diffraction, energy dispersive x-ray spectroscopy and micro-vickers hardness tester were employed to determine the structural, surface composition and surface hardness of the treated samples.

  6. Investigation of micro-structure and micro-hardness properties of 304L stainless steel treated in a hot cathode arc discharge plasma

    NASA Astrophysics Data System (ADS)

    Malik, Hitendra K.; Singh, Omveer; Dahiya, Raj P.

    2015-08-01

    We have established a hot cathode arc discharge plasma system, where different stainless steel samples can be treated by monitoring the plasma parameters and nitriding parameters independently. In the present work, a mixture of 70% N2 and 30% H2 gases was fed into the plasma chamber and the treatment time and substrate temperature were optimized for treating 304L Stainless Steel samples. Various physical techniques such as x-ray diffraction, energy dispersive x-ray spectroscopy and micro-vickers hardness tester were employed to determine the structural, surface composition and surface hardness of the treated samples.

  7. Solidification Behavior and Weldability of Dissimilar Welds Between a Cr-Free, Ni-Cu Welding Consumable and Type 304L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Sowards, Jeffrey W.; Liang, Dong; Alexandrov, Boian T.; Frankel, Gerald S.; Lippold, John C.

    2012-04-01

    The solidification behavior of a Cr-free welding consumable based on the Ni-Cu system was evaluated in conjunction with Type 304L stainless steel. The weld metal microstructure evolution was evaluated with optical and secondary electron microscopy, energy dispersive spectroscopy, X-ray diffraction, button melting, and thermodynamic (CALPHAD-based) modeling. Solidification partitioning patterns showed that higher dilutions of the filler metal by Type 304L increased segregation of Ti, Cu, and Si to interdendritic regions. Button melting experiments showed a widening of the solidification temperature range with increasing dilution because of the expansion of the austenite solidification range and formation of Ti(C,N) via a eutectic reaction. The model predictions showed good correlation with button melting experiments and were used to evaluate the nature of the Ti(C,N) precipitation reaction. Solidification cracking susceptibility of the weld metal was shown to increase with dilution of 304L stainless steel based on testing conducted with the cast pin tear test. The increase in cracking susceptibility is associated with expansion of the solidification temperature range and the presence of eutectic liquid at the end of solidification that wets solidification grain boundaries.

  8. Imitating seasonal temperature fluctuations for the H2S corrosion of 304L and 316L austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Davoodi, A.; Babaiee, M.; Pakshir, M.

    2013-07-01

    Temperature fluctuations are inevitable in sour oil and gas production. In this study, the H2S corrosion of 304L and 316L alloys was investigated at pH 3 and temperatures of 20-60 °C using DC and AC electrochemical techniques. Two-fold increases in the corrosion rates of both alloys were reported with increases in temperature to 60 °C. In the 304L alloy, the surface layer was observed to be 3% rougher and 34% thicker than that of the 316L alloy. The two alloys exhibited different corrosion behaviors in the temperature ranges of 20-40 °C and 40-60 °C. Although the 316L alloy revealed a greater corrosion resistance at the free potential condition, the passivation on the 304L alloy was significantly greater than that of the 316L alloy at 40 °C and 15 ppm H2S. The FeS2 and combined FeS2-MoS2 compounds contributed to the surface layer constituents in the 304L and 316L alloys, respectively. The increase in temperature kinetically provided more favorable conditions for FeS2 than MoS2 formation, i.e. it had a relatively constructive effect on the 304L alloy passivation.

  9. Investigation of Effect of Pre-Strain on Very High-Cycle Fatigue Strength of Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Ogawa, Takeshi; Nakane, Motoki; Masaki, Kiyotaka; Hashimoto, Shota; Ochi, Yasuo; Asano, Kyoichi

    This paper describes the effect of large pre-strain on very high cycle fatigue strength of austenitic stainless steels that are widely used in nuclear power plants. Fatigue tests were carried out on strain-hardened specimens. The material served in this study was type SUS316NG. Up to ±20% pre-strain was introduced to the materials, and the materials were mechanically machined into hourglass shaped smooth specimens. Some specimens were pre-strained after machining. Experiments were conducted in ultrasonic and rotating-bending fatigue testing machines. The S-N curves obtained in this study show that an increase in the magnitude of the pre-strain increases the fatigue strength of the material and this relationship is independent of the type of the pre-strain of tension or compression. Although all specimens fractured by the surface initiated fatigue cracks, one specimen fractured by an internal origin. However, this internal fracture did not cause a sudden drop in fatigue strength of type SUS316NG. Vickers hardness tests were carried out to ascertain the relationship between fatigue strength and hardness of the pre-strained materials. It was found that the increase in the fatigue limit of the pre-strained materials strongly depended on the hardness derived from an indentation size equal to the scale of stage I fatigue cracks.

  10. Effect of tensile pre-strain at different orientation on martensitic transformation and mechanical properties of 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Wibowo, F.; Zulfi, F. R.; Korda, A. A.

    2017-01-01

    Deformation induced martensite was studied in 316L stainless steel through tensile pre-strain deformation in the rolling direction (RD) and perpendicular to the rolling direction (LT) at various %pre-strain. The experiment was carried out at various given %pre-strain, which were 0%, 4.6%, 12%, 17.4%, and 25.2% for the RD, whereas for LT were 0%, 4.6%, 12%, 18%, and 26% for LT. Changes in the microstructure and mechanical properties were observed using optical microscope, tensile testing, hardness testing, and X-ray diffraction (XRD) analysis. The experimental results showed that the volume fraction of martensite was increased as the %pre-strain increased. In the same level of deformation by tensile pre-strain, the volume of martensite for RD was higher than that with LT direction. The ultimate tensile strength (UTS), yield strength (YS), and hardness of the steel were increased proportionally with the increases in %pre-strain, while the value of elongation and toughness were decreased with the increases in %pre-strain.

  11. Hydrogen Susceptibility of Pre-strained Type 316L Austenitic Stainless Steels in Aqueous Solutions

    NASA Astrophysics Data System (ADS)

    Mati, D.; Takasaki, A.; Uematsu, S.

    2017-09-01

    This paper presents the observations made as a result of hydrogen effects in austenitic stainless steels which led to reduction of its original mechanical properties. This paper therefore seeks to understand the mechanisms and effects induced by hydrogen leading to embrittlement. The samples of Type 316L austenitic stainless steel with 20% pre-strain were charged with hydrogen through galvanostastic cathodic loading for 12, 24, 36, and 48 hours respectively, with sample as Cathode and the platinum wire as Anode. Afterwards, they were fractured under tensile test at a slow strain rates. The loss of ductility was evident as observed by the brittle nature of fracture. Small pieces were cut-off near the fracture region and examined through XRD and SEM analysis. The peak widening and slight shifting of the peak positions was observed. The surface cracking was also observed, an indication of surface-induced stresses. The severity of the effects increased with the hydrogen loading time, which is predictive of a real service conditions for austenite steels in aqueous environments.

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

    PubMed Central

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

    2015-01-01

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

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

    SciTech Connect

    Gray, George Thompson; Livescu, Veronica; Rigg, P. A.; Trujillo, Carl Patrick; Cady, Carl McElhinney; Chen, Shuh-Rong; Carpenter, John S.; Lienert, Thomas J.; Fensin, Saryu Jindal; Knapp, Cameron M.; Beal, Roberta Ann; Morrow, Benjamin; Dippo, Olivia F.; Jones, David Robert; Martinez, Daniel Tito; Valdez, James Anthony

    2016-09-26

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

  14. Materials Reliability Program: Environmental Fatigue Testing of Type 304L Stainless Steel U-Bends in Simulated PWR Primary Water (MRP-137)

    SciTech Connect

    R.Kilian

    2004-12-01

    Laboratory data generated in the past decade indicate a significant reduction in component fatigue life when reactor water environmental effects are experimentally simulated. However, these laboratory data have not been supported by nuclear power plant component operating experience. In recent comprehensive review of laboratory, component and structural test data performed through the EPRI Materials Reliability Program, flow rate was identified as a critical variable that was generally not considered in laboratory studies but applicable in plant operating environments. Available data for carbon/low-alloy steel piping components suggest that high flow is beneficial regarding the effects of a reactor water environment. Similar information is lacking for stainless steel piping materials. This report documents progress made to date in an extensive testing program underway to evaluate the effects of flow rate on the corrosion fatigue of 304L stainless steel under simulated PWR primary water environmental conditions.

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

    SciTech Connect

    Sabooni, S.; Karimzadeh, F.; Enayati, M.H.; Ngan, A.H.W.; Jabbari, H.

    2015-11-15

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

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

    PubMed

    Leskovšek, Vojteh; Godec, Matjaž; Kogej, Peter

    2016-08-05

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

  17. Fracture and the formation of sigma phase, M[sub 23]C[sub 6], and austenite from delta-ferrite in an AISI 304L stainless steel

    SciTech Connect

    Tseng, C.C.; Shen, Y.; Thompson, S.W.; Krauss, G. . Dept. of Metallurgical and Materials Engineering); Mataya, M.C. )

    1994-06-01

    The decomposition of delta-ferrite and its effects on tensile properties and fracture of a hot-rolled AISI 304L stainless steel plate were studied. Magnetic response measurements of annealed specimens showed that the transformation rate of delta-ferrite was highest at 720 C. Transformation behavior was characterized by light microscopy, transmission electron microscopy, scanning electron microscopy, and energy-dispersive spectroscopy on thin foils. The initial transformation of delta-ferrite ([delta]) to austenite ([gamma]) and a chromium-rich carbide (M[sub 23]C[sub 6]) occurred by a lamellar eutectoid reaction, [sigma] [r reversible] M[sub 23]C[sub 6] + [gamma]. The extent of the reaction was limited by the low carbon content of the 304L plate, and the numerous, fine M[sub 23]C[sub 6] particles of the eutectoid structure provide microvoid nucleation sites in tensile specimens annealed at 720 C for short times. Sigma phase ([sigma]) formed as a result of a second eutectoid reaction, [delta] [r reversible] [sigma] + [gamma]. Brittle fracture associated with the plate-shaped sigma phase of the second eutectoid structure resulted in a significant decrease in reduction of area (RA) in the transverse tensile specimens. The RA for longitudinal specimens was not affected by the formation of sigma phase. Tensile strengths were little affected by delta-ferrite decomposition products in either longitudinal or transverse orientations.

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

    NASA Astrophysics Data System (ADS)

    Leskovšek, Vojteh; Godec, Matjaž; Kogej, Peter

    2016-08-01

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

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

    PubMed Central

    Leskovšek, Vojteh; Godec, Matjaž; Kogej, Peter

    2016-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  1. Beam-broadening effects in STEM/EDS measurement of radiation-induced segregation in high-purity 304L stainless steel

    SciTech Connect

    Busby, J.T.; Was, G.S.; Allen, T.R. |; Kenik, E.A.; Zaluzec, N.J.

    1997-10-01

    Radiation-induced segregation (RIS) is the spatial redistribution of elements at defect sinks such as grain boundaries and free surfaces during irradiation. This phenomenon has been studied in a wide variety of alloys and has been linked to irradiation-assisted stress corrosion cracking (IASCC) of nuclear reactor core components. Therefore, accurate determination of the grain boundary composition is important in understanding its effects on environmental cracking. Radiation-induced segregation profiles are routinely measured by scanning-transmission electron microscopy using energy-dispersive X-ray spectroscopy (STEM-EDS) and Auger electron spectroscopy (AES). Because of the narrow width of the segregation profile (typically less than 10-nm full width at half-maximum), the accuracy of grain boundary concentration measurements using STEM/EDS depends on the characteristics of the analyzing instrument, specifically, the excited volume in which x-rays are generated. This excited volume is determined by both electron beam diameter and the primary electron beam energy. Increasing the primary beam energy in STEM/EDS produces greater measured grain boundary segregation, as the reduced electron beam broadening a smaller excited volume. In this work, the effect of beam broadening is assessed on segregation measurements in a 304L stainless steel sample irradiated with 3.2 MeV protons at 400 C to doses of 3.0 and 0.1 dpa. The STEM/EDS measurements are also compared to measurements made using AES.

  2. Effect of microstructure and chemical composition on localized corrosion resistance of a AISI 304L stainless steel after nanopulsed-laser surface melting

    NASA Astrophysics Data System (ADS)

    Pacquentin, W.; Caron, N.; Oltra, R.

    2015-11-01

    Changes induced in the surface properties of AISI 304L stainless steel when it is treated with a nanopulsed ytterbium-doped fiber laser were investigated to determine the microscale distribution of its physico-chemical properties. A Gaussian energy distribution was created with a radius of 71 μm (1/e2) at the focal point. Local investigations were carried out using transmission electron microscopy to consider the effect of overlapping individual laser impacts. The results obtained reveal that laser surface melting leads to changes in the crystallographic structure of the steel through the formation of a δ-ferritic phase. It also results in the creation of an oxide layer that increases the corrosion resistance of the steel, with the chemical composition, structure and thickness of this layer being dependent on the overlap percentage and the position along the beam radius. Measurement of the localized corrosion resistance in a 30 g L-1 NaCl solution using polarization curves found that optimal laser treatment conditions can led to an increase in the breakdown potential of more than 500 mV, which corresponds to a significant improvement in corrosion resistance.

  3. Properties of High-Frequency Sub-Wavelength Ripples on Stainless Steel 304L under Ultra Short Pulse Laser Irradiation

    NASA Astrophysics Data System (ADS)

    Mitko, V. S.; Römer, G. R. B. E.; Veld, A. J. Huis in `t.; Skolski, J. Z. P.; Obona, J. V.; Ocelík, V.; De Hosson, J. T. M.

    The paper concentrates on surface texturing on sub-micro meter scale with ultra short laser pulses that has several applications, e.g. changing the hydrophilic/hydrophobic performance, optical or tribological properties of materials. In general, the formations of wavy structures, or ripples on a surface irradiated by short pulse lasers has been observed experimentally since 1965, and are usually referred to as Laser Induced Periodic Surface Structures (LIPSS). Generally Low Spatial Frequency LIPSS (LSFL) and High Spatial Frequency LIPSS (HSFL) are observed. The existing theoretical models do not describe the origin, nor growth of the ripples satisfactorily. That is why the experimental approach still plays a leading role in the investigation of ripple formation. In this paper we study the development of HSFL and LSFL as a result of picosecond laser pulses on a surface of stainless steel. Influences of number of pulses and pulse overlap on ripples growth were examined.

  4. Effect of pre-strain on creep of three AISI 316 austenitic stainless steels in relation to reheat cracking of weld-affected zones

    NASA Astrophysics Data System (ADS)

    Auzoux, Q.; Allais, L.; Caës, C.; Monnet, I.; Gourgues, A. F.; Pineau, A.

    2010-05-01

    Microstructural modifications induced by welding of 316 stainless steels and their effect on creep properties and relaxation crack propagation were examined. Cumulative strain due to multi-pass welding hardens the materials by increasing the dislocation density. Creep tests were conducted on three plates from different grades of 316 steel at 600 °C, with various carbon and nitrogen contents. These plates were tested both in the annealed condition and after warm rolling, which introduced pre-strain. It was found that the creep strain rate and ductility after warm rolling was reduced compared with the annealed condition. Moreover, all steels exhibited intergranular crack propagation during relaxation tests on Compact Tension specimens in the pre-strained state, but not in the annealed state. These results confirmed that the reheat cracking risk increases with both residual stress triaxiality and pre-strain. On the contrary, high solute content and strain-induced carbide precipitation, which are thought to increase reheat cracking risk of stabilised austenitic stainless steels did not appear as key parameters in reheat cracking of 316 stainless steels.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    DOE PAGES

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

    2015-02-11

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

  7. Finite-element modelling of low-temperature autofrettage of thick-walled tubes of the austenitic stainless steel AISI 304 L: Part II. Thick-walled tube with cross-bore

    NASA Astrophysics Data System (ADS)

    Feng, H.; Donth, B.; Mughrabi, H.

    1998-01-01

    In part I, the autofrettage of a smooth thick-walled tube of the austenitic stainless steel AISI 304 L was studied by finite-element (FE) modelling. It was shown that low- temperature autofrettage is more efficient than autofrettage at room temperature, since it produces a larger beneficial compressive residual tangential (hoop) stress at the inner bore of the tube and hence permits a more significant enhancement of the fatigue resistance against pulsating internal pressure. The objective of the present study (part II) was to investigate the technically more relevant case of a thick-walled tube with a cross-bore made of the same steel. For this purpose, three-dimensional FE calculations were performed in order to characterize the influences of the autofrettage pressure and temperature on the stress and strain changes, in particular at the site of the cross-bore, also taking into account the effects of work hardening and reverse yielding. The results indicate that low-temperature autofrettage can also be applied advantageously in the case of thick-walled tubes with a cross-bore by virtue of the significantly larger residual compressive stresses, compared to room temperature autofrettage. From the quantitative FE calculations, the optimal combination of autofrettage temperature and pressure were concluded to lie in the range of 0965-0393/6/1/007/img1 to 0965-0393/6/1/007/img2, respectively. The calculated results were found to be in fair agreement with the measured values.

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

    SciTech Connect

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

    2015-02-11

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

  9. Relationships between the Phase Transformation Kinetics, Texture Evolution, and Microstructure Development in a 304L Stainless Steel under Biaxial Loading Conditions: Synchrotron X-Ray and Electron Back-Scatter Diffraction Studies

    SciTech Connect

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

    2015-05-01

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

  10. Welding of Vanadium, Tantalum, 304L and 21-6-9 Stainless Steels, and Titanium Alloys at Lawrence Livermore National Laboratory using a Fiber Delivered 2.2 kW Diode Pumped CW Nd:YAG Laser

    SciTech Connect

    Palmer, T; Elmer, J; Pong, R; Gauthier, M

    2006-06-16

    This report summarizes the results of a series of laser welds made between 2003 and 2005 at Lawrence Livermore National Laboratory (LLNL). The results are a compilation of several, previously unpublished, internal LLNL reports covering the laser welding of vanadium, tantalum, 304L stainless steel, 21-6-9 (Nitronic 40) steel, and Ti-6Al-4V. All the welds were made using a Rofin Sinar DY-022 diode pumped continuous wave Nd:YAG laser. Welds are made at sharp focus on each material at various power levels and travel speeds in order to provide a baseline characterization of the performance of the laser welder. These power levels are based on measurements of the output power of the laser system, as measured by a power meter placed at the end of the optics train. Based on these measurements, it appears that the system displays a loss of approximately 10% as the beam passes through the fiber optic cable and laser optics. Since the beam is delivered to the fixed laser optics through a fiber optic cable, the effects of fiber diameter are also briefly investigated. Because the system utilizes 1:1 focusing optics, the laser spot size at sharp focus generally corresponds to the diameter of the fiber with which the laser is delivered. Differences in the resulting weld penetration in the different materials system are prevalent, with the welds produced on the Nitronic 40 material displaying the highest depths (> 5 mm) and minimal porosity. A Primes focusing diagnostic has also been installed on this laser system and used to characterize the size and power density distribution of the beams as a function of both power and focus position. Further work is planned in which this focusing diagnostic will be used to better understand the effects of changes in beam properties on the resulting weld dimensions in these and other materials systems.

  11. Effect of Plastic Pre-straining on Residual Stress and Composition Profiles in Low-Temperature Surface-Hardened Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Bottoli, Federico; Christiansen, Thomas L.; Winther, Grethe; Somers, Marcel A. J.

    2016-08-01

    The present work deals with the evaluation of the residual stress profiles in expanded austenite by applying grazing incidence X-ray diffraction (GI-XRD) combined with successive sublayer removal. Annealed and deformed ( ɛ eq=0.5) samples of stable stainless steel EN 1.4369 were nitrided or nitrocarburized. The residual stress profiles resulting from the thermochemical low-temperature surface treatment were measured. The results indicate high-residual compressive stresses of several GPa's in the nitrided region, while lower-compressive stresses are produced in the carburized case. Plastic deformation in the steel prior to thermochemical treatment has a hardly measurable influence on the nitrogen-rich zone, while it has a measurable effect on the stresses and depth of the carbon-rich zone.

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

    SciTech Connect

    Kanne, W.R. Jr.

    1996-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  14. 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

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

    PubMed Central

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

    2017-01-01

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

  16. Reverse Transformation of Deformation-Induced Phases and Associated Changes in the Microstructure of Explosively Clad Ti-5Ta-2Nb and 304L SS

    NASA Astrophysics Data System (ADS)

    Prasanthi, T. N.; Sudha, C.; Murugesan, S.; Thomas Paul, V.; Saroja, S.

    2015-10-01

    Ti-5Ta-2Nb alloy was joined to 304L austenitic stainless steel by explosive cladding technique. Explosive cladding resulted in the formation of deformation-induced martensite in 304L SS and fcc phase of Ti in the Ti-5Ta-2Nb side of the joint. The stability of these metastable phases was systematically studied using high-temperature X-ray diffraction technique and transmission electron microscopy, which enabled the optimization of the temperature window for post-cladding heat treatments.

  17. Are Sulfate Reducing Bacteria Important to the Corrosion of Stainless Steels?

    DTIC Science & Technology

    2009-01-01

    behavior of types 304 and 316 stainless steels for direct corrosion rate determination of experimental alloys 304L and 316L . However, the software...5 i 304L 316L I I I us + 904L Figure 2. Calculated corrosion rates for alloys 430, 304L , 316L , and 904L after modeled exposure to...elements. Derivatization decreased in the following order 430> 304L > 316L >904L. Laboratory results compared favorably with electrochemical model

  18. SCC Propagation Rate of Type 304, 304L Steels Under Oceanic Air Environment

    SciTech Connect

    Akio Kosaki

    2006-07-01

    Corrosion integrity of canister in the concrete cask for spent fuel storage is very important because the canister serves to maintain the sealability over the storage period of 40 to 60 years. Natural exposure and accelerated corrosion tests of conventional stainless steels for canister, that are Type 304, 304L, and 316(LN), for concrete cask's canister have been conducted by using many three Point Bending (3PB) test specimens and compared. The SCC propagation rates in Type 304 and 304L at the natural condition were about 1.2 E-12 to 1.8 E-11 m/s at the K (Stress Intensity Factor) range of 0.6 to 9.0 MPa/m, and that of the accelerate test (60 degrees C, 95%RHS., filled with NaCl mist.) were about 1.0 E-10 to 3.5 E-9 m/s at the K range of 0.3 to 32 MPa/m. The SCC propagation rates under both natural and accelerated conditions were independent with K. Both da/dt values of the direct exposure test and of the under glass exposure test were in the same scattering band. (author)

  19. Finite Element Modeling and Validation of Residual Stresses in 304 L Girth Welds

    SciTech Connect

    Dike, J.J.; Ortega, A.R.; Cadden, C.H.; Rangaswamy, P. Brown, D.

    1998-06-01

    Three dimensional finite element simulations of thermal and mechanical response of a 304 L stainless steel pipe subjected to a circumferential autogenous gas tungsten arc weld were used to predict residual stresses in the pipe. Energy is input into the thermal model using a volumetric heat source. Temperature histories from the thermal analysis are used as loads in the mechanical analyses. In the mechanical analyses, a state variable constitutive model was used to describe the material behavior. The model accounts for strain rate, temperature, and load path histories. The predicted stresses are compared with x-ray diffraction determinations of residual stress in the hoop and circumferential directions on the outside surface of the pipe. Calculated stress profiles fell within the measured data. Reasons for observed scatter in measured stresses are discussed.

  20. Deformation temperature, strain rate, and irradiation microstructure effects on localized plasticity in 304L SS

    SciTech Connect

    Cole, J.I.; Brimhall, J.L.; Vetrano, J.S.; Bruemmer, S.M.

    1995-12-31

    The present study examines the deformation behavior of ion-irradiated, low-carbon 304L stainless steel to investigate the influence of irradiation microstructure, deformation temperature and strain rate on localized plasticity. Dislocation loop character, size and density are linked to changes in deformation character. Lower doses produce small faulted loops and stacking fault tetrahedra that impede dislocation mobility. Dislocations are pinned at defects and require higher stress to break free from the defects. Larger defects take the form of faulted Frank loops that can interact with glide dislocations to form microtwins at lower temperatures and faster strain rates. Deformation at higher temperatures and slower strain rates promotes interactions between glide dislocations and loops leading to loop annihilation. Dislocation free zones or ``channels`` form where further plastic deformation is highly localized. Results are compared to limited observations for neutron-irradiated materials. These irradiation-induced changes can be an important concern for light-water reactor (LWR) stainless steel (SS) structural components due to a reduced damage tolerance, and potential susceptibility to environmental cracking such as irradiation-assisted stress corrosion cracking (IASCC).

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

    DOE PAGES

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

    2017-01-12

    Drawn 304L stainless steel tubing was subjected to 42 different annealing heat treatments with the goal of initializing a microstructural model to select a heat treatment to soften the tubing from a hardness of 305 Knoop to 225–275 Knoop. The amount of recrystallization and grain size caused by 18 heat treatments were analyzed via optical microscopy and image analysis, revealing the full range of recrystallization from 0 to 100%. The formation of carbides during the longer duration and higher-temperature heat treatments was monitored via transmission electron microscope evaluation. The experimental results informed a model which includes recovery, recrystallization, and grainmore » growth to predict microstructure and hardness. After initialization of the model, it was able to predict hardness with a R2 value of 0.95 and recrystallization with an R2 value of 0.99. As a result, the model was then utilized in the design and testing of a heat treatment to soften the tubing.« less

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

    NASA Astrophysics Data System (ADS)

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

    2006-03-01

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

  3. Corrosion Resistance of 304L SS Spray Coated with Zirconia Nanoparticles

    NASA Astrophysics Data System (ADS)

    Maheswari, A. Uma; Sivakumar, M.; Indhumathi, N.; Mohan, Sreedevi R.

    2016-09-01

    Influence of substrate temperature on corrosion (in 3.5% NaCl) and wear resistance of nanostructured zirconia thin film coated 304L SS substrates are studied by electrochemical and nano-indentation methods. This analysis shows 304L SS substrate spray coated with nanostructured zirconia at substrate temperature closer to the boiling point of the spray solvent ethanol exhibited good corrosion and wear resistance behaviour. This is because of the compressive stress developed during film fabrication at lower substrate temperature (∼50 °C) and hence constrains the indentation plasticity, which leads to higher indentation load than the bare 304L SS.

  4. Novel pre-strain method for dielectric electroactive polymers

    NASA Astrophysics Data System (ADS)

    Newell, Brittany; Krutz, Gary; Stewart, Frank; Pascal, Kevin

    2016-04-01

    Dielectric electroactive polymers have demonstrated their significant potential in a variety of applications due to their material strength and elastomeric material properties. Mechanical pre-strain has been shown to enhance material actuation potential significantly. However, with this enhancement comes sacrifices. Mechanical pre-strain imposes a stiff mechanical boundary on the dielectric material in order to maintain the strain. In this research, investigations were made into the mechanisms of mechanical pre-strain and into alternate pre-strain methods. These studies discovered alternate methods capable of producing enhanced pre-strains and final actuation without the addition of the solid strain boundary.

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  7. Effect of Laser Surface Melting on the Microstructure and Pitting Corrosion Resistance of 304L SS Weldment

    NASA Astrophysics Data System (ADS)

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

    2017-10-01

    The manuscript presents the effect of laser surface melting (LSM) on the microstructural variations and pitting corrosion resistance of 304L SS weldment fabricated by gas tungsten arc welding of 304L SS plates using 308L SS filler wire. The weld region was examined by X-ray radiography for defect detection. LSM of 304L SS weldment was performed using Nd:YAG pulsed laser. Microstructural evaluation was carried out using optical and electron back scatter diffraction techniques. The microstructure of 304L SS base was found to be austenitic, while the weld region of 304L SS weldment contained delta ferrite distributed in austenite matrix. The microstructure of LSM 304L SS weldment was found to be homogeneous austenite matrix with sparsely distributed ferrite. Ferrite measurements showed a decrease in the percentage ferrite in the fusion zone of 304L SS weldment after LSM. A profound enhancement in the pitting corrosion resistance was observed after LSM, which could be attributed to the homogeneous microstructure and decrease in the ferrite content. Pit density was found to be higher in the heat-affected zone of the weldment. Very few pits were observed in the LSM 304L SS weldment compared to the as-weldment.

  8. Effect of Ga on the Wettability of CuGa10 on 304L Steel

    NASA Astrophysics Data System (ADS)

    Silze, Frank; Wiehl, Gunther; Kaban, Ivan; Kühn, Uta; Eckert, Jürgen; Pauly, Simon

    2015-08-01

    In the present work, the effect of Ga on the wetting behavior of the Cu-rich braze filler CuGa10 (wt pct, Cu90.8Ga9.2 at. pct) on the steel 304L was investigated. For this, the macroscopic and microscopic effects governing the wetting of pure Ga, pure Cu, and CuGa10 alloy (wt pct) on the austenitic steel were analyzed and compared. Contact angle and surface tension measurements were carried out by means of the sessile drop technique, and, in addition, the phase formation at the interface was determined. Pure liquid Ga spreads on 304L, which supposedly is related to the formation of intermetallic Fe-Ga phases growing into the liquid Ga. Depending on the annealing time, FeGa3 and Fe14.5Ga12 were identified. In contrast, CuGa10 as well as pure Cu shows secondary wetting on the steel surface. Especially, liquid Cu prefers spreading laterally and vertically along the grain boundaries of the steel substrate. In spite of rather similar mechanisms, CuGa10 wets 304L steel at lower rate than pure Cu above the liquidus temperature.

  9. 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

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

    DTIC Science & Technology

    2004-12-31

    compared to type 304L stainless steel. Keywords: Welding , Corrosion , Stainless steel, Nickel, Copper, Palladium , Molybdenum, Dilution... Corrosion Center, Dept. of Materials Science and Engineering **Dept. of Industrial, Welding and Systems Engineering The Ohio State University...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) *Fontana Corrosion Center, Dept. of Materials Science and Engineering **Dept. of Industrial, Welding and

  11. Chemically pre-strained dielectric elastomers finite element analysis

    NASA Astrophysics Data System (ADS)

    Newell, Brittany; Krutz, Gary; Stewart, Frank; Pascal, Kevin

    2017-04-01

    The applications and feasibility of utilizing dielectric elastomer electroactive polymers in the industrial and medical sectors has drastically increased in recent years due to significant improvements in actuation potential, manufacturing, the introduction of new materials and modeling capabilities. One such development is the introduction of chemical pre-strain as a method of providing enhanced actuation. The purpose of this study was to utilize finite element analysis to analyze the mechanical actuation of an industrial fluoropolymer with chemical induced pre-strain and validate the model with experiential results. Results generated from the finite element analysis showed similar trends to results produced experimentally.

  12. 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.

  13. Comparison of Strength and Serration at Cryogenic Temperatures among 304L, 316L and 310S Steels

    NASA Astrophysics Data System (ADS)

    Shibata, K.; Ogata, T.; Nyilas, A.; Yuri, T.; Fujii, H.; Ohmiya, S.; Onishi, T.; Weiss, K. P.

    2008-03-01

    Tensile tests of 310S steel were performed at temperatures below 300 K and the yield strength and deformation behavior were compared with those of 304L and 316L steels. Computer simulations were also carried out to graph stress-elongation curves in order to discuss the effects of martensitic transformations induced during deformation on their strengths and deformation behavior at low temperatures. Tensile tests showed that yield strength of 310S steel is highest and that of 304L is lowest. The differences in yield strengths between 316L and 310S steels and between 304L and 316L steels are larger than those expected from the differences in solid solution strengthening. This can be explained by the effect of the strain through γ to ɛ martensitic transformation induced by elastic stress in 304L and 316L steels. The strength level and the shape of stress-elongation curves at cryogenic temperatures excluding serration can be qualitatively revealed by simulation when higher strength of ɛ phase comparing to α' phase and the window effect of α' were considered simultaneously. In liquid hydrogen, the three steels exhibit large serrations on the stress-elongation curves after the deformation near to the ultimate stress, while the curves are smooth before the onset of the serration. Such serrations in liquid hydrogen could not be revealed by simulation.

  14. 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.

  15. On the interface between LENS deposited stainless steel 304L repair geometry and cast or machined components.

    SciTech Connect

    Smugeresky, John E.; Harris, Marc F.; Griffith, Michelle Lynn; Gill, David Dennis; Robino, Charles Victor

    2004-12-01

    Laser Engineered Net Shaping (LENS) is being evaluated for use as a metal component repair/modification process for the NWC. An aspect of the evaluation is to better understand the characteristics of the interface between LENS deposited material and the substrate on which it is deposited. A processing and metallurgical evaluation was made on LENS processed material fabricated for component qualification tests. A process parameter evaluation was used to determine optimum build parameters and these parameters were used in the fabrication of tensile test specimens to study the characteristics of the interface between LENS deposited material and several types of substrates. Analyses of the interface included mechanical properties, microstructure, and metallurgical integrity. Test samples were determined for a variety of geometric configurations associated with interfaces between LENS deposited material and both wrought base material and previously deposited LENS material. Thirteen different interface configurations were fabricated for evaluation representing a spectrum of deposition conditions from complete part build, to hybrid substrate-LENS builds, to repair builds for damaged or re-designed housings. Good mechanical properties and full density were observed for all configurations. When tested to failure, fracture occurred by ductile microvoid coalescence. The repair and hybrid interfaces showed the same metallurgical integrity as, and had properties similar to, monolithic LENS deposits.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

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

    PubMed Central

    Zubelewicz, Aleksander; Oliferuk, Wiera

    2016-01-01

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

  18. Dissimilar welding of nickel-based Alloy 690 to SUS 304L with Ti addition

    NASA Astrophysics Data System (ADS)

    Lee, H. T.; Jeng, S. L.; Yen, C. H.; Kuo, T. Y.

    2004-10-01

    This study investigates the effects of Ti addition on the weldability, microstructure and mechanical properties of a dissimilar weldment of Alloy 690 and SUS 304L. Shielding metal arc welding (SMAW) is employed to butt-weld two plates with three welding layers, where each layer is deposited in a single pass. To investigate the effects of Ti addition, the flux coatings of the electrodes used in the welding process are modified by varying additions of either a Ti-Fe compound or a Ti powder. The results indicate that the microstructure of the fusion zone (FZ) is primarily dendritic. With increasing Ti content, it is noted that the microstructure changes from a columnar dendritic to an equiaxed dendritic, in which the primary dendrite arm spacing (PDAS) becomes shorter. Furthermore, it is observed that the amount of Al-Ti oxide phase increases in the inter-dendritic region, while the amount of Nb-rich phase decreases. Moreover, the average hardness of the FZ increases slightly. The results indicate that Ti addition prompts a significant increase in the elongation of the weldment (i.e. 36.5%, Ti: 0.41 wt%), although the tensile strength remains relatively unchanged. However, at an increased Ti content of 0.91 wt%, an obvious reduction in the tensile strength is noted, which can be attributed to a general reduction in the weldability of the joint.

  19. Impact Testing of Stainless Steel Material at Cold Temperatures

    SciTech Connect

    Spencer D. Snow; D. Keith Morton; Robert K. Blandford

    2008-07-01

    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 during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern are not well documented. However, a previous paper [1] reported on impact testing and analysis results performed at the Idaho National Laboratory using 304/304L and 316/316L stainless steel base material specimens at room and elevated temperatures. The goal of the work presented herein is to add recently completed impact tensile testing results at -20 degrees F conditions for dual-marked 304/304L and 316/316L stainless steel material specimens (hereafter referred to as 304L and 316L, respectively). Recently completed welded material impact testing at -20 degrees F, room, 300 degrees F, and 600 degrees F is also reported. Utilizing a drop-weight impact test machine and 1/4-inch to 1/2-inch thick dog-bone shaped test specimens, the impact tests achieved strain rates in the 4 to 40 per second range, depending upon the material temperature. Elevated true stress-strain curves for these materials reflecting varying strain rates and temperatures are presented herein.

  20. High compressive pre-strains reduce the bending fatigue life of nitinol wire.

    PubMed

    Gupta, Shikha; Pelton, Alan R; Weaver, Jason D; Gong, Xiao-Yan; Nagaraja, Srinidhi

    2015-04-01

    Prior to implantation, Nitinol-based transcatheter endovascular devices are subject to a complex thermo-mechanical pre-strain associated with constraint onto a delivery catheter, device sterilization, and final deployment. Though such large thermo-mechanical excursions are known to impact the microstructural and mechanical properties of Nitinol, their effect on fatigue properties is still not well understood. The present study investigated the effects of large thermo-mechanical pre-strains on the fatigue of pseudoelastic Nitinol wire using fully reversed rotary bend fatigue (RBF) experiments. Electropolished Nitinol wires were subjected to a 0%, 8% or 10% bending pre-strain and RBF testing at 0.3-1.5% strain amplitudes for up to 10(8) cycles. The imposition of 8% or 10% bending pre-strain resulted in residual set in the wire. Large pre-strains also significantly reduced the fatigue life of Nitinol wires below 0.8% strain amplitude. While 0% and 8% pre-strain wires exhibited distinct low-cycle and high-cycle fatigue regions, reaching run out at 10(8) cycles at 0.6% and 0.4% strain amplitude, respectively, 10% pre-strain wires continued to fracture at less than 10(5) cycles, even at 0.3% strain amplitude. Furthermore, over 70% fatigue cracks were found to initiate on the compressive pre-strain surface in pre-strained wires. In light of the texture-dependent tension-compression asymmetry in Nitinol, this reduction in fatigue life and preferential crack initiation in pre-strained wires is thought to be attributed to compressive pre-strain-induced plasticity and tensile residual stresses as well as the formation of martensite variants. Despite differences in fatigue life, SEM revealed that the size, shape and morphology of the fatigue fracture surfaces were comparable across the pre-strain levels. Further, the mechanisms underlying fatigue were found to be similar; despite large differences in cycles to failure across strain amplitudes and pre-strain levels, cracks

  1. Corrosion Resistance of Stainless Steels in Biodiesel

    NASA Astrophysics Data System (ADS)

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

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

  2. Optimization of Heat Treatments for Reversion of Strain-Induced Martensite in 304L SS Explosive Clad

    NASA Astrophysics Data System (ADS)

    Prasanthi, T. N.; Sudha, C.; Parida, P. K.; Dasgupta, Arup; Saroja, S.

    2016-02-01

    Explosive clad joints of 304L SS and Ti-5Ta-2Nb alloy, fabricated for an important application in the spent nuclear fuel reprocessing industry showed formation of deformation induced metastable α' martensite and fcc Ti phase in SS and TiTaNb alloy respectively. A biphasic structure consisting of metastable phases is not preferred for industrial applications due to degradation of corrosion and mechanical properties of the structural materials during service. Hence, it is essential to carry out post cladding heat treatments. The results reported in this paper provide evidence for the presence of α' phase in 304L SS in `as clad' joints and its reversion process during thermal exposure. The temperature window in the range of 400-700 °C and time was optimized based on complete transformation of the metastable phases to parent phases, and avoiding the formation of brittle Fe-Ti intermetallics at the interface. A systematic increase in the fraction of austenite phase associated with the reversion phenomena has been studied using electron back scattered diffraction and transmission electron microscopy. Orientation relationship between product fcc and parent bcc phases was found to obey the K-S relationship. The reverted γ phase was found to nucleate within the martensite laths. A temperature of 550 °C for duration of about 10 h was found to be optimum for the post cladding treatments of the explosive clad joints.

  3. Processing and structure of high-energy-rate-forged 21-6-9 and 304L forgings

    SciTech Connect

    Mataya, M.C.; Carr, M.J.; Krenzer, R.W.; Krauss, G.

    1981-08-10

    Two 304L and three Nitronic 40 (21-6-9) high energy rate processed forgings were studied to determine interrelationships that exist between forging history, mechanical properties, microstructure, macrostructure, and substructure. A striking observation is the wide variation in properties and structure between different forgings and also between different locations within an individual forging. Variations were related to either finishing temperature of the last forming stage or to the forming sequence. For example, lower finishing temperatures resulted in higher dislocation densities and therefore higher strengths. Higher finishing temperatures promoted dynamic recrystallization, lower dislocation densities, and lower strengths. With respect to forming sequence, locations in the forging which are formed first undergo a number of additional thermal cycles while the rest of the part is being formed. These areas are usually recrystallized and have lower dislocation densities, and therefore lower strengths relative to locations formed later in the sequence.

  4. Radial Distribution of Martensitic Phase Transformation in a Metastable Stainless Steel under Torsional Deformation: A Synchrotron X-ray Diffraction Study

    SciTech Connect

    Cakmak, Ercan; Choo, Hahn; An, Ke; Ren, Yang

    2011-01-01

    The strain-induced martensitic phase transformation in a metastable 304 L stainless steel under torsional deformation was investigated using synchrotron X-ray diffraction. The measured radial distribution of the martensite phase fraction in a solid cylindrical specimen agrees well with the prediction based on a combination of transformation kinetics and a radial plastic strain distribution equation.

  5. 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.

  6. 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.

  7. Atom probe, AFM, and STM studies on vacuum-fired stainless steels.

    PubMed

    Stupnik, A; Frank, P; Leisch, M

    2009-04-01

    The surface morphology of grades 304L and 316LN stainless steels, after low-temperature bake-out process and vacuum annealing, has been studied by atomic force microscopy (AFM) and scanning tunnelling microscopy (STM). The local elemental composition on the surface before and after thermal treatment has been investigated by atom probe (AP) depth profiling measurements. After vacuum annealing, AFM and STM show significant changes in the surface structure and topology. Recrystallization and surface reconstruction is less pronounced on the 316LN stainless steel. AP depth profiling analyses result in noticeable nickel enrichment on the surface of grade 304L samples. Since hydrogen recombination is almost controlled by surface structure and composition, a strong influence on the outgassing behaviour by the particular surface microstructure can be deduced.

  8. Corrosion of stainless steel piping in a high manganese fresh water

    SciTech Connect

    Avery, R.E.; Lutey, R.W.; Musick, J.; Pinnow, K.E.; Tuthill, A.H.

    1996-07-01

    In March of 1993, about two years after startup in early 1991, pinhole leaks were found in the 16 in. (406 mm) type 304L stainless steel (UNS S30403) raw water piping at the Brunswick-Topsham Water District (BTWD) Potable Water Treatment Plant (PWTP) in Brunswick, Maine. The low chloride manganese-containing well water is chlorinated in the pump house. After reaching the plant, the raw water is handled in type 304L stainless steel (UNS S30403) piping. It was initially felt that the corrosion might be the microbiologically influenced corrosion (MIC) type corrosion described by Tverberg, Pinnow, and Redmerski. Investigation showed that the role of manganese and chlorine differed, in important respects, from that described by Tverberg et. al., and that heat tint scale may have played a significant role in the corrosion that occurred at the BTWD plant.

  9. 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.

  10. Effect of pre-strain on ratcheting behavior of A668 Class D steel

    NASA Astrophysics Data System (ADS)

    Tripathy, S.; Mondal, A. K.; Dutta, K.

    2016-02-01

    The aim of this investigation is to study the effect pre-strain (0%, 2%, 4% and 8%) on ratcheting behavior of ASTM A668 Class D steel in different heat treatment conditions (normalized and hardened-tempered). Ratcheting tests were carried out at room temperature on cylindrical specimens having 12.5 mm gauge length and 6 mm gauge diameter. The results include reduced strain accumulation with increasing prestrain level due to work hardening of the pre-strained samples. Further, cyclic hardening takes place during ratcheting deformation.

  11. Wrinkling of a stiff thin film bonded to a pre-strained, compliant substrate with finite thickness.

    PubMed

    Ma, Yinji; Xue, Yeguang; Jang, Kyung-In; Feng, Xue; Rogers, John A; Huang, Yonggang

    2016-08-01

    A stiff thin film bonded to a pre-strained, compliant substrate wrinkles into a sinusoidal form upon release of the pre-strain. Many analytical models developed for the critical pre-strain for wrinkling assume that the substrate is semi-infinite. This critical pre-strain is actually much smaller than that for a substrate with finite thickness (Ma Y et al. 2016 Adv. Funct. Mater. (doi:10.1002/adfm.201600713)). An analytical solution of the critical pre-strain for a system of a stiff film bonded to a pre-strained, finite-thickness, compliant substrate is obtained, and it agrees well with the finite-element analysis. The finite-thickness effect is significant when the substrate tensile stiffness cannot overwhelm the film tensile stiffness.

  12. Wrinkling of a stiff thin film bonded to a pre-strained, compliant substrate with finite thickness

    NASA Astrophysics Data System (ADS)

    Ma, Yinji; Xue, Yeguang; Jang, Kyung-In; Feng, Xue; Rogers, John A.; Huang, Yonggang

    2016-08-01

    A stiff thin film bonded to a pre-strained, compliant substrate wrinkles into a sinusoidal form upon release of the pre-strain. Many analytical models developed for the critical pre-strain for wrinkling assume that the substrate is semi-infinite. This critical pre-strain is actually much smaller than that for a substrate with finite thickness (Ma Y et al. 2016 Adv. Funct. Mater. (doi:10.1002/adfm.201600713)). An analytical solution of the critical pre-strain for a system of a stiff film bonded to a pre-strained, finite-thickness, compliant substrate is obtained, and it agrees well with the finite-element analysis. The finite-thickness effect is significant when the substrate tensile stiffness cannot overwhelm the film tensile stiffness.

  13. 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.

  14. High Strength Stainless Steel Properties that Affect Resistance Welding

    SciTech Connect

    Kanne, W.R.

    2001-08-01

    This report discusses results of a study on selected high strength stainless steel alloy properties that affect resistance welding. The austenitic alloys A-286, JBK-75 (Modified A-286), 21-6-9, 22-13-5, 316 and 304L were investigated and compared. The former two are age hardenable, and the latter four obtain their strength through work hardening. Properties investigated include corrosion and its relationship to chemical cleaning, the effects of heat treatment on strength and surface condition, and the effect of mechanical properties on strength and weldability.

  15. The microstructure and fracture behavior of the dissimilar alloy 690-SUS 304L joint with various Nb addition

    NASA Astrophysics Data System (ADS)

    Lee, H. T.; Jeng, S. L.; Kuo, T. Y.

    2003-05-01

    This study investigates the microstructure and fracture behavior of dissimilar weldments of alloy 690 and SUS 304L for various additions of niobium (0.1, 1.03, 2.49, and 3.35 wt pct) in the flux. With identical parameters and procedures, weldments were butt welded by the shielding metal arc welding (SMAW) process using three layers, with each layer being deposited in a single pass. The results indicate that the microstructure of the fusion zone was primarily dendritic and that the contents of Ni, Cr, and Fe within this zone remain relatively constant and resemble alloy 690. With Nb addition, it is noted that the microstructure changes from a cellular to columnar dendrite and equiaxed dendrite. Meanwhile, the dendrite arm spacing reduces and the secondary arms grow longer. Moreover, the composition of the interdendritic phase, whose precipitate volume percentage increases from 5 to 25 pct, changes from Al-Ti-O to Nb rich. The spread of the interdendritic phase is less in the root bead than in the cap bead due to the greater influence of base metal dilution in this region. Mechanical tests indicate that Nb addition increases the average hardness of the weldment and reduces its elongation prior to rupture. However, the tensile strength is essentially unchanged by Nb addition. It is found that the average hardness of the root bead is generally lower than the cap bead, and that the tensile specimens all rupture in the fusion zone, with the fracture surfaces exhibiting ductile features. It is noted that the cap bead tends to rupture interdendritically with increasing Nb addition. Finally, fractography shows that the dimples in the root become larger and shallower with Nb addition and are rich with an interdendritic phase.

  16. Evaluation of Giga-cycle Fatigue Properties of Austenitic Stainless Steels Using Ultrasonic Fatigue Test

    NASA Astrophysics Data System (ADS)

    Takahashi, Kyouhei; Ogawa, Takeshi

    Ultrasonic fatigue tests have been performed in austenitic stainless steel, SUS316NG, in order to investigate giga-cycle fatigue strength of pre-strained materials, i.e. 5, 10 and 20% tensile pre-strains and -20% compressive pre-strain. The pre-strains were applied before specimen machining. The austenitic stainless steels are known to exhibit remarkable self-heating during the fatigue experiment. Therefore, heat radiation method was established by setting fatigue specimens in a low temperature chamber at about -100°C. The self-heating was controlled by intermittent loading condition, which enabled us to maintain the test section of the specimens at about room temperature. The results revealed that the fatigue strength increased with increasing pre-strain levels. Fish-eye fracture was observed for -20% pre-strained specimen fractured at 4.11×107 cycles, while the other specimens exhibited ordinary fatigue fracture surface originated from stage I facet on the specimen surface. The increase in fatigue limit was predicted by Vickers hardness, HV, which depended on the size of indented region. The prediction was successful using HV values obtained by the size of the indented region similar to those of the stage I facets.

  17. Welding Stainless Steels and Refractory Metals Using Diode-Pumped Continuous Wave Nd:YAG Lasers

    SciTech Connect

    Palmer, T A; Elmer, J W; Pong, R; Gauthier, M D

    2004-09-27

    This report provides an overview of a series of developmental welding studies performed on a 2.2 kW Rofin Sinar DY-022 Diode Pumped Continuous Wave (CW) Nd:YAG welder at Lawrence Livermore National Laboratory (LLNL). Several materials systems, ranging from refractory metals, such as commercially pure tantalum and vanadium, to austenitic stainless steels, including both 304L and 21-6-9 grades, are examined. Power input and travel speed are systematically varied during the welding of each materials system, and the width, depth, and cross sectional area of the resulting weld fusion zones are measured. These individual studies are undertaken in order to characterize the response of the welder to changes in these welding parameters for a range of materials and to determine the maximum depth of penetration of which this welder is capable in each materials system. The maximum weld depths, which are on the order of 5.4 mm, are observed in the 21-6-9 austenitic stainless steel at the maximum laser power setting (2200 W) and a slow travel speed (6.4 mm/sec). The next highest weld depth is observed in the 304L stainless steel, followed by that observed in the vanadium and, finally, in the tantalum. Porosity, which is attributed to the collapse of the keyhole during welding, is also observed in the welds produced in tantalum, vanadium, and 304L stainless steel. Only the 21-6-9 austenitic stainless steel welds displayed little or no porosity over the range of welding parameters. Comparisons with similar laser welding systems are also made for several of these same materials systems. When compared with the welds produced by these other systems, the LLNL system typically produces welds of an equivalent or slightly higher depth.

  18. RESULTS OF EXPERIMENT TO DETERMINE CORROSION RATES FOR 304L IN HB-LINE DISSOLVER VESSEL VENTILATION SYSTEM

    SciTech Connect

    Mickalonis, J; Kathryn Counts, K

    2008-02-22

    Radioactive material being processed as part of the DE3013 program for HB-Line will result in the presence of chlorides, and in some cases fluorides, in the dissolver. Material Science and Technology developed an experimental plan to evaluate the impact of chloride on corrosion of the dissolver vessel ventilation system. The plan set test variables from the proposed operating parameters, previous test results, and a desired maximum chloride concentration for processing. The test variables included concentrations of nitric acid, fluorides and chlorides, and the presence of a welded and stressed metal coupon. Table 1 contains expected general corrosion rates in the HB-Line vessel vent system from dissolution of 3013 contents of varying nitric acid and chloride content. These general corrosion rates were measured upstream of the condenser in the experiment's offgas system near the entrance to the dissolver. However, they could apply elsewhere in the offgas system, depending on factors not simulated in the testing, including offgas system temperatures and airflow. Localized corrosion was significant in Tests One, Two, and Three. This corrosion is significant because it will probably be the first mode of penetration of the 304L steel in several places in the system. See Table 2. For Tests One and Three, the penetration rate of localized corrosion was much higher than that for general corrosion. It was approximately four times higher in Test One and at least 45 times higher in Test Three, penetrating an entire coupon thickness of 54 mils in 186 hours or less. There was no significant difference in corrosion between welded areas and un-welded areas on coupons. There was also no significant attack on stressed portions of coupons. It is probable that the lack of corrosion was because the stressed areas were facing downwards and offered no place for condensation or deposits to form. Had deposits formed, pitting may have occurred and led to stress corrosion cracking. The

  19. Attenuation of shock waves in copper and stainless steel

    SciTech Connect

    Harvey, W.B.

    1986-06-01

    By using shock pins, data were gathered on the trajectories of shock waves in stainless steel (SS-304L) and oxygen-free-high-conductivity copper (OFHC-Cu). Shock pressures were generated in these materials by impacting the appropriate target with thin (approx.1.5 mm) flying plates. The flying plates in these experiments were accelerated to high velocities (approx.4 km/s) by high explosives. Six experiments were conducted, three using SS-304L as the target material and three experiments using OFHC-Cu as the target material. Peak shock pressures generated in the steel experiments were approximately 109, 130, and 147 GPa and in the copper experiments, the peak shock pressures were approximately 111, 132, and 143 GPa. In each experiment, an attenuation of the shock wave by a following release wave was clearly observed. An extensive effort using two characteristic codes (described in this work) to theoretically calculate the attenuation of the shock waves was made. The efficacy of several different constitutive equations to successfully model the experiments was studied by comparing the calculated shock trajectories to the experimental data. Based on such comparisons, the conclusion can be drawn that OFHC-Cu enters a melt phase at about 130 GPa on the principal Hugoniot. There was no sign of phase changes in the stainless-steel experiments. In order to match the observed attenuation of the shock waves in the SS-304L experiments, it was necessary to include strength effects in the calculations. It was found that the values for the parameters in the strength equations were dependent on the equation of state used in the modeling of the experiments. 66 refs., 194 figs., 77 tabs.

  20. Circular pre-strained dielectric elastomer actuator: modeling, simulation and experimental verification

    NASA Astrophysics Data System (ADS)

    Wissler, Michael; Mazza, Edoardo; Kovacs, Gabor

    2005-05-01

    Reliable models are required for the design and optimization of dielectric elastomer actuators. Thereby knowledge of the constitutive behavior of the elastomer is of crucial importance. In this work a pre-strained circular actuator made of a dielectric elastomer is investigated: constitutive models based on uniaxial data are verified by comparing calculation results with experimental observations. An analytical model is derived for the instantaneous response to an activation voltage in the pre-strained circular actuator and a finite element (FE) model is used to simulate the time dependent behavior. Hyperelastic models are used and three strain energy formulations (Yeoh, Ogden and Mooney-Rivlin) are compared in their predictive capabilities. The results of the calculations with the three strain energy forms differ significantly, although all forms were successfully fitted to the same uniaxial data set. Predictions of the actuator behavior based on the Yeoh form agree to a great extent with measurements of the response at different pre-strain levels and activation voltages.

  1. A novel method of fabricating laminated silicone stack actuators with pre-strained dielectric layers

    NASA Astrophysics Data System (ADS)

    Hinitt, Andrew D.; Conn, Andrew T.

    2014-03-01

    In recent studies, stack based Dielectric Elastomer Actuators (DEAs) have been successfully used in haptic feedback and sensing applications. However, limitations in the fabrication method, and materials used to con- struct stack actuators constrain their force and displacement output per unit volume. This paper focuses on a fabrication process enabling a stacked elastomer actuator to withstand the high tensile forces needed for high power applications, such as mimetics for mammalian muscle contraction (i.e prostheses), whilst requiring low voltage for thickness-mode contractile actuation. Spun elastomer layers are bonded together in a pre-strained state using a conductive adhesive filler, forming a Laminated Inter-Penetrating Network (L-IPN) with repeatable and uniform electrode thickness. The resulting structure utilises the stored strain energy of the dielectric elas- tomer to compress the cured electrode composite material. The method is used to fabricate an L-IPN example, which demonstrated that the bonded L-IPN has high tensile strength normal to the lamination. Additionally, the uniformity and retained dielectric layer pre-strain of the L-IPN are confirmed. The described method is envisaged to be used in a semi-automated assembly of large-scale multi-layer stacks of pre-strained dielectric layers possessing a tensile strength in the range generated by mammalian muscle.

  2. Localized weld metal corrosion in stainless steel water tanks

    SciTech Connect

    Strum, M.J.

    1995-05-25

    The rapidly developed leaks within the TFC and TFD tanks (LLNL groundwater treatment facilities) were caused by localized corrosion within the resolidified weld metal. The corrosion was initiated by the severe oxidation of the backsides of the welds which left the exposed surfaces in a condition highly susceptible to aqueous corrosion. The propagation of surface corrosion through the thickness of the welds occurred by localized corrosive attack. This localized attack was promoted by the presence of shielded aqueous environments provided by crevices at the root of the partial penetration welds. In addition to rapid corrosion of oxidized surfaces, calcium carbonate precipitation provided an additional source of physical shielding from the bulk tank environment. Qualification testing of alternate weld procedures showed that corrosion damage can be prevented in 304L stainless steel GTA welds by welding from both sides while preventing oxidation of the tank interior through the use of an inert backing gas such as argon. Corrosion resistance was also satisfactory in GMA welds in which oxidized surfaces were postweld cleaned by wire brushing and chemically passivated in nitric acid. Further improvements in corrosion resistance are expected from a Mo-containing grade of stainless steel such as type 316L, although test results were similar for type 304L sheet welded with type 308L filler metal and type 316L sheet welded with type 316L filler metal.

  3. Stainless steel

    SciTech Connect

    Lula, R.A.

    1985-01-01

    This book discusses the stainless steels for high-strength, heat-resistant or corrosion-resistant applications. It is a treatment of the properties and selection of stainless steels. Up-to-date information covers physical, mechanical and chemical properties of all stainless grades, including the new ferritic and duplex grades. The book covers physical metallurgy as well as processing and service characteristics, including service in corrosive environments. It deals with wrought and cast stainless steels and reviews fabrication from cold-forming to powder metallurgy.

  4. 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

  5. Three-dimensional development of tensile pre-strained annulus fibrosus cells for tissue regeneration: An in-vitro study

    SciTech Connect

    Chuah, Yon Jin; Lee, Wu Chean; Wong, Hee Kit; Kang, Yuejun; Hee, Hwan Tak

    2015-02-01

    Prior research has investigated the immediate response after application of tensile strain on annulus fibrosus (AF) cells for the past decade. Although mechanical strain can produce either catabolic or anabolic consequences to the cell monolayer, little is known on how to translate these findings into further tissue engineering applications. Till to date, the application and effect of tensile pre-strained cells to construct a three-dimensional (3D) AF tissue remains unknown. This study aims to investigate the effect of tensile pre-strained exposure of 1 to 24 h on the development of AF pellet culture for 3 weeks. Equibiaxial cyclic tensile strain was applied on AF monolayer cells over a period of 24 h, which was subsequently developed into a cell pellet. Investigation on cellular proliferation, phenotypic gene expression, and histological changes revealed that tensile pre-strain for 24 h had significant and lasting effect on the AF tissue development, with enhanced cell proliferation, and up-regulation of collagen type I, II, and aggrecan expression. Our results demonstrated the regenerative ability of AF cell pellets subjected to 24 h tensile pre-straining. Knowledge on the effects of tensile pre-strain exposure is necessary to optimize AF development for tissue reconstruction. Moreover, the tensile pre-strained cells may further be utilized in either cell therapy to treat mild disc degeneration disease, or the development of a disc construct for total disc replacement. - Highlights: • Establishment of tensile pre-strained cell line population for annulus development. • Tensile strain limits collagen gene expression declination in monolayer culture. • Tensile pre-strained cells up-regulate their matrix protein in 3D pellet culture.

  6. Effects of pre-strain on the intrinsic pressure sensitivity of polymer optical fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Pedersen, Jens Kristian Mølgaard; Woyessa, Getinet; Nielsen, Kristian; Bang, Ole

    2017-04-01

    We experimentally demonstrate a scheme for improving the intrinsic pressure sensitivity of fiber Bragg-gratings (FBGs) inscribed in polymer optical fibers by applying pre-strain in order to suppress the pressure induced mechanical contraction of the fiber. This contraction would otherwise contribute to a blueshift of the Brag-wavelength, counteracting the dominant redshift caused by the stress-optic effect, which effectively reduces the pressure sensitivity of the FBG. By applying this technique we are able to improve the sensitivity of the FBG from 2.8 pm/bar to 7.3 pm/bar.

  7. Boundary condition and pre-strain effects on the free standing indentation response of graphene monolayer.

    PubMed

    Zhou, Lixin; Wang, Yugang; Cao, Guoxin

    2013-11-27

    Using molecular mechanics simulations, we investigated the true pre-stress/pre-strain state of graphene in free standing indentation and the effect of the pre-strain (ε0) on the free standing indentation response of graphene is also considered. We found that there is essentially no effective pre-tension in graphene during free standing indentation and the reported pre-tensile stress determined from the indentation tests does not show the true pre-stress state of graphene, which is a 'fake stress' caused by the assumption (the indenter tip displacement is equal to the displacement of graphene) typically used in the classic indentation analysis. A negative ε0 will increase the van der Waals (VDW) interaction between the indenter tip and graphene to cause a larger overestimation of both values of the elastic modulus (E) and the nonlinear elastic constant (c) of graphene from the classic indentation analysis. However, applying a positive ε0 in graphene, the VDW effect will be significantly decreased, and a more accurate value of E can be obtained, but the value of c will decrease to zero, which may become an effective way to more accurately obtain the elastic stiffness of graphene from indentation tests.

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

    NASA Astrophysics Data System (ADS)

    Kumar, R.; Balasubramanian, M.

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

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

    NASA Astrophysics Data System (ADS)

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

    2002-07-01

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

  10. Microtopographic Analysis of Part-Through Crack Growth in Alloy 304L Plate-type Tension Specimens

    SciTech Connect

    W. R. Lloyd; E. D. Steffler; J. H. Jackson

    2003-04-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) used their microtopography analysis method to examine the fracture process in two Type 304 stainless steel, part-through crack, plate-type specimens. The two specimens had different initial defect geometries – one being nearly semicircular and moderately deep, the other being longer and shallower. The microtopographic analysis allowed determination of parameters such as: the crack tip opening displacement at initiation; the crack tip opening angle during ductile tearing; the crack mouth opening at through-thickness penetration; and, the incremental crack front profiles throughout the crack growth process. In essence, these data provide a nearly complete description of the entire ductile fracture process for the two cases examined. We describe the microtopographic analysis procedure as it was applied to these two specimens. Crack growth profiles predicted by the microtopography analysis are compared with those shown by heat tinting of the actual fracture subsurface, showing excellent agreement. Several areas of ductile crack growth theory relevant to the microtopographic method of analysis are discussed, including possible effects on the accuracy of the analyses. The accuracy of the resultant data is reviewed, and found acceptable or better. Areas for additional development of the microtopography method to improve accuracy in three-dimensional ductile fracture analysis are identified.

  11. Impact Testing of Stainless Steel Material at Room and Elevated Temperatures

    SciTech Connect

    Dana K. Morton; Spencer D. Snow; Tom E. Rahl; Robert K. Blandford

    2007-07-01

    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 during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern are not well documented. However, three previous papers [1, 2, 3] reported on impact testing and analysis results performed at the Idaho National Laboratory using 304/304L and 316/316L stainless steel base material specimens that began the investigation of these characteristics. The goal of the work presented herein is to add the results of additional tensile impact testing for 304/304L and 316/316L stainless steel material specimens. Utilizing a drop-weight impact test machine and 1/4-inch to 1/2-inch thick dog-bone shaped test specimens, additional tests achieved target strain rates of 5, 10, and 22 per second at room temperature, 300, and 600 degrees Fahrenheit. Elevated true stress-strain curves for these materials at each designated strain rate and temperature are presented herein.

  12. Product consistency testing of three reference glasses in stainless steel and perfluoroalkoxy resin vessels

    SciTech Connect

    Olson, K.M.; Smith, G.L.; Marschman, S.C.

    1995-03-01

    Because of their chemical durability, silicate glasses have been proposed and researched since the mid-1950s as a medium for incorporating high-level radioactive waste (HLW) generated from processing of nuclear materials. A number of different waste forms were evaluated and ranked in the early 1980s; durability (leach resistance) was the highest weighted factor. Borosilicate glass was rated the best waste form available for incorporation of HLW. Four different types of vessels and three different glasses were used to study the possible effect of vessel composition on durability test results from the Production Consistency Test (PCT). The vessels were 45-m 304 stainless steel vessels, 150-m 304 L stainless steel vessels, and 60-m perfluoroalkoxy (PFA) fluoropolymer resin vessels. The three glasses were the Environmental Assessment glass manufactured by Corning Incorporated and supplied by Westinghouse Savannah River company, and West Valley Nuclear Services reference glasses 5 and 6, manufactured and supplied by Catholic University of America. Within experimental error, no differences were found in durability test results using the 3 different glasses in the 304L stainless steel or PFA fluoropolymer resin vessels over the seven-day test period.

  13. Intergranular stress-corrosion cracking of austenitic stainless steels in PWR boric-acid storage systems

    SciTech Connect

    Macdonald, D.D.; Cragnolino, G.A.; Olemacher, J.; Chen, T.Y.; Dhawale, S.

    1982-08-01

    A review is presented of the available literature on the intergranular stress corrosion cracking (IGSCC) of austenitic stainless steels at temperatures below 100/sup 0/C, as well as the results of an experimental investigation of the IGSCC of Types 304, 304L, and 316L stainless steels conducted in boric acid environments of the type employed in pressurized nuclear reactors (PWRs) for nuclear shim control. The susceptibility of furnace sensitized Type 304SS to IGSCC was studied using slow strain rate tests as a function of pH, temperature, potential, and concentration of suspected contaminants: chloride, thiosulfate, and tetrathionate. Possible alternate alloys, such as Types 304L and 316L stainless steels, were also tested under those specific conditions that render Type 304SS susceptible to cracking. Corrosion potentials that can be attained in air-saturated boric acid solutions in the presence of the above mentioned species were measured in order to evaluate the propensity towards intergranular cracking under conditions simulating those that prevail in service.

  14. Porosity in millimeter-scale welds of stainless steel : three-dimensional characterization.

    SciTech Connect

    Aagesen, Larry K.; Madison, Jonathan D.

    2012-05-01

    A variety of edge joints utilizing a continuous wave Nd:YAG laser have been produced and examined in a 304-L stainless steel to advance fundamental understanding of the linkage between processing and resultant microstructure in high-rate solidification events. Acquisition of three-dimensional reconstructions via micro-computed tomography combined with traditional metallography has allowed for qualitative and quantitative characterization of weld joints in a material system of wide use and broad applicability. The presence, variability and distribution of porosity, has been examined for average values, spatial distributions and morphology and then related back to fundamental processing parameters such as weld speed, weld power and laser focal length.

  15. Nondestructive Evaluation of Strain Distribution and Fatigue Distribution from Austenitic Stainless Steel by Using Magnetic Sensors

    SciTech Connect

    Tsuchida, Y.; Enokizono, M.; Oka, M.; Yakushiji, T.

    2007-03-21

    Austenitic stainless steel transforms from austenitic crystal structure to martensitic crystal structure after applying strain or stress. Because martensitic crystal structures have magnetization, strain evaluation and fatigue evaluation can be performed by measuring magnetic properties. This paper describes the measurement of leakage magnetic flux density of remanent magnetization for the strain evaluation and the fatigue evaluation by a typical Hall element sensor for SUS 304 and SUS 304L and by a high-sensitivity thin-film flux-gate magnetic sensor for SUS 316 and SUS 316L.

  16. Improving the corrosion resistance of power metallurgy austenitic stainless steels through infiltration

    SciTech Connect

    Velasco, F.; Ibars, J.R.; Ruiz-Roman, J.M.; Torralba, J.M.; Ruiz-Prieto, J.M.

    1996-01-01

    Types 316L (UNS S31603) and 304L (UNS S30403) sintered stainless steels (SS) were produced in a laboratory furnace at 1,330 C and infiltrated with copper and bronze in different percentages to determine their effect on the corrosion resistance of the presintered SS. Corrosion resistance was studied by immersion in sulfuric, hydrochloric and nitric acids and by electrochemical potentiokinetic reactivation (EPR) tests. Both copper and bronze improved corrosion resistance highly in HCl and boiling H{sub 2}SO{sub 4}. Results of EPR and boiling H{sub 2}SO{sub 4} immersion tests showed good concordance.

  17. Pre-strain effect on frequency-based impact energy dissipation through a silicone foam pad for shock mitigation [Pre-strain effect on the frequency response of shock mitigation through a silicone foam pad

    DOE PAGES

    Sanborn, Brett; Song, Bo; Smith, Scott

    2015-12-29

    Silicone foams have been used in a variety of applications from gaskets to cushioning pads over a wide range of environments. Particularly, silicone foams are used as a shock mitigation material for shock and vibration applications. Understanding the shock mitigation response, particularly in the frequency domain, is critical for optimal designs to protect internal devices and components more effectively and efficiently. The silicone foams may be subjected to pre-strains during the assembly process which may consequently influence the frequency response with respect to shock mitigation performance. A Kolsky compression bar was modified with pre-compression capabilities to characterize the shock mitigationmore » response of silicone foam in the frequency domain to determine the effect of pre-strain. Lastly, a silicone sample was also intentionally subjected to repeated pre-strain and dynamic loadings to explore the effect of repeated loading on the frequency response of shock mitigation.« less

  18. Pre-strain effect on frequency-based impact energy dissipation through a silicone foam pad for shock mitigation [Pre-strain effect on the frequency response of shock mitigation through a silicone foam pad

    SciTech Connect

    Sanborn, Brett; Song, Bo; Smith, Scott

    2015-12-29

    Silicone foams have been used in a variety of applications from gaskets to cushioning pads over a wide range of environments. Particularly, silicone foams are used as a shock mitigation material for shock and vibration applications. Understanding the shock mitigation response, particularly in the frequency domain, is critical for optimal designs to protect internal devices and components more effectively and efficiently. The silicone foams may be subjected to pre-strains during the assembly process which may consequently influence the frequency response with respect to shock mitigation performance. A Kolsky compression bar was modified with pre-compression capabilities to characterize the shock mitigation response of silicone foam in the frequency domain to determine the effect of pre-strain. Lastly, a silicone sample was also intentionally subjected to repeated pre-strain and dynamic loadings to explore the effect of repeated loading on the frequency response of shock mitigation.

  19. 2014 Accomplishments-Tritium aging studies on stainless steel: Fracture toughness properties of forged stainless steels-Effect of hydrogen, forging strain rate, and forging temperature

    SciTech Connect

    Morgan, Michael J.

    2015-02-01

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

  20. The influence of shock pre-strain and peak pressure on spall behavior of 4340 steel

    SciTech Connect

    Zurek, A.K.; Frantz, C.E.; Gray, G.T. III.

    1990-01-01

    A fundamental study of the influence of peak stress amplitude and pre-strain on the spall fracture of pearlitic 4340 steel is presented. Spall tests were performed at projectile velocities to achieve approximately 5, 10 and 15 GPa peak stress amplitudes. Some spall tests were preceded by a pre-shock and recovery test at 10 and 15 GPa. Spall strength measurements suggest that there is a decrease in the spall strength of 4340 with an increase in the shock wave amplitude as the transition pressure of 13.1 GPa is approached. At this transition pressure, a substantial increase in the spall strength, as well as a change in a mode of fracture from brittle to ductile are observed, both attributed to the allotropic phase transformation at this amplitude. 18 refs., 4 figs.

  1. Light-induced sequential self-folding of pre-strained polymer sheets

    NASA Astrophysics Data System (ADS)

    Genzer, Jan; Liu, Ying; Shaw, Brandi; Dickey, Michael

    2014-03-01

    Self-folding is a self-assembly process that causes a predefined 2D template to fold into a desired 3D structure with high fidelity.We have developed a simple method of self-folding that uses predefined ink ``hinges'' printed onto pre-strained polymer sheets via a desk top printer. The ink absorbs external light, causing the area underneath the hinge to heat up and relax the strain in the hinge regions gradually across the sheet thickness. This process results in folding the sheet at the hinge region. We will demonstrate that sequential folding of multiple hinges on the same sample can be programmed by changing the light source and ink color of the hinge. We have successfully employed this strategy to produce complex origami shapes.

  2. Prediction of the bending behavior after pre-strain of an aluminum alloy

    NASA Astrophysics Data System (ADS)

    Pradeau, A.; Thuillier, S.; Yoon, J. W.

    2016-10-01

    The present work is focused on the modeling of sheet metal mechanical behavior up to rupture, including anisotropy and hardening. The mechanical behavior of an AA6016 alloy was characterized at room temperature in tension, simple shear and hydraulic bulging. The initial anisotropy was described with the Yld2004-18p yield criterion coupled to a mixed hardening law. Concerning rupture, an uncoupled phenomenological criterion of Mohr-Coulomb type will be used. For the material parameter identification, an inverse methodology was used with the objective of reducing the gap between experimental and numerical data. Finally, validation of the results was performed on bending tests with different amplitudes of tension pre-strain in order to reach or not rupture in the bent area.

  3. 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.

  4. Effects of fiber pre-strain on the healing efficiency of thermoset polymers

    NASA Astrophysics Data System (ADS)

    Ajisafe, Oludayo

    -tensile load. The Ultrasonic C-scan and SEM were used to examine the healed cracks. It was found that the beams with 100% pre-strained fiber were able to recover repeatedly about 50% of its peak tensile strength; the beams with 50% pre-strained fiber, 43%; and the beams with un-stretched fibers were able to recover about 21% of its original peak tensile strength. Also it was found that the higher the pre-tension the higher the recovery stress seen during the healing cycle.

  5. 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.

  6. Three-dimensional folding of pre-strained polymer sheets via absorption of laser light

    SciTech Connect

    Liu, Ying; Genzer, Jan E-mail: mddickey@ncsu.edu Dickey, Michael D. E-mail: mddickey@ncsu.edu; Miskiewicz, Matthew; Escuti, Michael J. E-mail: mddickey@ncsu.edu

    2014-05-28

    Patterned light from a laser can induce rapid self-folding of pre-strained polymer sheets. Black ink coated on the sheet absorbs the light, which converts the photon energy into thermal energy that heats the sheet locally; the temperature of the sheet is highest at the surface where the light impinges on the sheet and decreases through the sheet thickness. The gradient of temperature induces a gradient of strain relaxation through the depth of the sheet, which causes folding within seconds of irradiation. The pattern of laser light that irradiates the compositionally homogeneous two-dimensional (2D) substrate dictates the resulting three-dimensional (3D) shape. Unlike most approaches to self-folding, the methodology described here requires no patterning of pre-defined hinges. It opens up the possibility of using a patterning technique that is inherently 2D to form 3D shapes. The use of lasers also enables systematic control of key process parameters such as power, intensity, and the pattern of light (i.e., beam width and shape). The rate of folding and folding angle measured with respect to these parameters provide an indirect quantification of heat loss in the sample and thereby identify the threshold power and power intensity that must be delivered to the hinge for folding to occur.

  7. Uniaxial Pre-strain and Free Recovery (UPFR) as a Flexible Technique for Nitinol Characterization

    NASA Astrophysics Data System (ADS)

    Cadelli, A.; Manjeri, R. M.; Sczerzenie, F.; Coda, A.

    2016-03-01

    The measurement of phase transformation temperatures of superelastic (SE) and shape memory (SM) NiTi alloy products and components was studied in this work. The transformation temperatures of a set of twenty different 300 μm NiTi superelastic wires were measured by two well-established and standardized techniques, namely differential scanning calorimetry (DSC) and bend and free recovery (BFR) and then compared with the results from the Uniaxial Pre-Strain and Free Recovery (UPFR) test. UPFR is a tension-based test, whose aim is to overcome the limitations associated with BFR testing. Within this work, a test procedure has been set up and validated. UPFR is found to be the only method showing a very strong correlation with the mechanical properties measured using the standard uniaxial tensile test method for superelastic NiTi alloy. Further, UPFR has been validated as a robust technique for measuring the R-phase and austenitic transformation temperatures in specimens of various sizes, composition, and of different geometries. This technique overcomes the limitations of BFR and DSC which cannot be used for testing products such as 25 μm SM wire, a 50 μm SE strip, and different springs and microsprings for actuation.

  8. Effect of internal heating during hot compression testing on the stress-strain behavior and hot working characteristics of Alloy 304L

    SciTech Connect

    Mataya, M.C.; Sackschewsky, V.E.

    1993-05-01

    Temperature change from conversion of deformation to internal heat, and its effect on stress-strain behavior of alloy 304L was investigated by initially isothermal (temperature of specimen, compression dies, environment equilibrated at initiation of test) uniaxial compression. Strain rate was varied 0.01 s{sup {minus}1} to 1 s{sup {minus}1} (thermal state of specimen varied from nearly isothermal to nearly adiabatic). Specimens were deformed at 750 to 1150 to a strain of 1. Change in temperature with strain was calculated via finite element analysis from measured stress-strain data and predictions were confirmed with thermocouples to verify the model. Temperature increased nearly linearly at the highest strain rate, consistent with temperature rise being a linear function of strain (adiabatic). As strain rate was lowered, heat transfer from superheated specimen to cooler dies caused sample temperature to increase and then decrease with strain as the sample thinned and specimen-die contact area increased. As-measured stress was corrected. Resulting isothermal flow curves were compared to predictions of a simplified method suggested by Thomas and Shrinivasan and differences are discussed. Strain rate sensitivity, activation energy for deformation, and flow curve peak associated with onset of dynamic recrystallization were determined from both as-measured and isothermal stress-strain data and found to vary widely. The impact of utilizing as-measured stress-strain data, not corrected for internal heating, on results of a number of published investigations is discussed.

  9. The effect of anisotropy on the intermediate and final form in deep drawing of SS304L, with high draw ratios: Experimentation and numerical simulation

    NASA Astrophysics Data System (ADS)

    Qayyum, F.; Shah, M.; Muqeet, A.; Afzal, J.

    2016-08-01

    High deep draw ratio of metal sheets is often required in industry to produce complex structural components and is considered to be problematic beyond a draw ratio of 1.7. In addition, anisotropy of material plays a great role in the final form of deep drawn products. In this research AISI SS304 L high draw ratio deep drawing (HDR) cups have been developed by using multiple intermediate annealing steps. The form of flange produced at each draw step is recorded, Numerical simulation of the process is carried out using ABAQUS StandardTM. Accurate modelling of the process requires anisotropic parameters. Tensile tests at 0o, 15o, 30o, 45o, 60o, 75o, 90o to the rolling direction are carried out to determine the Lankford coefficients and hardening coefficients in each direction. The detailed material data obtained is then applied to simulate the HDR process. The forms recorded experimentally are compared with simulation results and conclusion is drawn as to the accuracy of the simulation.

  10. HYDROGEN EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEELS

    SciTech Connect

    Morgan, M

    2008-03-28

    The effect of hydrogen on the fracture toughness properties of Types 304L, 316L and 21-6-9 forged stainless steels was investigated. Fracture toughness samples were fabricated from forward-extruded forgings. Samples were uniformly saturated with hydrogen after exposure to hydrogen gas at 34 MPa or 69 and 623 K prior to testing. The fracture toughness properties were characterized by measuring the J-R behavior at ambient temperature in air. The results show that the hydrogen-charged steels have fracture toughness values that were about 50-60% of the values measured for the unexposed steels. The reduction in fracture toughness was accompanied by a change in fracture appearance. Both uncharged and hydrogen-charged samples failed by microvoid nucleation and coalescence, but the fracture surfaces of the hydrogen-charged steels had smaller microvoids. Type 316L stainless steel had the highest fracture toughness properties and the greatest resistance to hydrogen degradation.

  11. 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.

  12. 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.

  13. Effect of Pre-straining on the Shape Recovery of Fe-Mn-Si-Cr-Ni Shape Memory Alloys

    NASA Astrophysics Data System (ADS)

    Maji, Bikas C.; Krishnan, Madangopal; Verma, Amit; Basu, R.; Samajdar, I.; Ray, Ranjit K.

    2015-02-01

    The effect of pre-straining on the shape recovery behavior of Fe-14Mn-6Si-9Cr-5Ni (wt pct) shape memory alloy (SMA) has been studied. The shape recovery associated with the reverse ɛ martensitic transformation, i.e., ɛ → γ, was characterized by dilatometry using specimens which were pre-strained to different extent (0 to 14 pct). Dilatometric studies revealed that in Fe-Mn-Si-Cr-Ni SMA, the shape recovery takes place in two stages: (i) in the first stage, the unpinned fraction of stress-induced ɛ martensite reverts back to parent phase γ in the temperature regime of 353 K to 653 K (80 °C to 380 °C) and (ii) in the second stage the remaining "pinned" ɛ martensite is unpinned by the decomposition of deformation-induced α' martensite in the temperature range of 743 K to 893 K (470 °C to 620 °C). The amount of recovery in the first stage decreases with pre-strain, whereas it increases in the second stage. The ɛ → γ transformation finish temperature, A f, increases with increase in pre-strain amount, though the reverse transformation start temperature, A S, remains unaffected. Microstructural characterization revealed that the amount of deformation-induced α' martensite depends on the mode of straining and the crystallographic texture of the starting material. The reversion of α' martensite is seen to occur by the precipitation of Fe5Ni3Si2-type intermetallic π-phase within these plates.

  14. On the effect of pre-straining on the fatigue behavior of a particulate-reinforced metal-matrix composite

    SciTech Connect

    Beyer, G.; Biermann, H.; Mughrabi, H.

    1997-04-15

    Since the development of the Duralcan melt-stirring process, particulate-reinforced metal-matrix composites (MMCs) can be produced in sufficient amounts and at low enough cost to meet industrial demands. Aluminium-alloy based MMCs with Al{sub 2}O{sub 3} particulate reinforcement fabricated by casting processes have already been applied as engine components and other automotive parts, mainly because of their high strength and stiffness and their superior wear resistance. Another property of great interest and practical importance is the fatigue behavior of MMCs which has been studied repeatedly in the past. A particular aspect which has not been investigated so far is the influence of pre-straining on the fatigue properties. In view of the possibility of pre-straining during the finishing process, its effect on the fatigue behavior is of interest. Here the authors report results on the fatigue behavior of a ceramic-particle reinforced MMC obtained in the framework of a more extended study. In an earlier publication, quantitative data on the stress-dependence of the Young`s modulus in tension and compression were reported. The present paper deals with the influence of pre-straining on the fatigue properties and on the fatigue life of the aluminium-matrix composite AA6061-Al{sub 2}O{sub 3}-15p-T6. The mechanical tests were supplemented by microstructural investigations, using in particular optical, scanning (SEM) and transmission electron microscopy (TEM).

  15. LOCALIZED CORROSION OF AUSTENITIC STAINLESS STEELEXPOSED TO MIXTURES OF PLUTONIUM OXIDE AND CHLORIDE SALTS

    SciTech Connect

    Zapp, P; Kerry Dunn, K; Jonathan Duffey, J; Ron Livingston, R; Zane Nelson, Z

    2008-11-21

    Laboratory corrosion tests were conducted to investigate the corrosivity of moist plutonium oxide/chloride (PuO{sub 2}/Cl-) salt mixtures on 304L and 316L stainless steel coupons. The tests exposed flat coupons for pitting evaluation and 'teardrop' stressed coupons for stress corrosion cracking (SCC) evaluation at room temperature to various mixtures of PuO{sub 2} and chloride-bearing salts for periods up to 500 days. The two flat coupons were placed so that the solid oxide/salt mixture contacted about one half of the coupon surface. One teardrop coupon was placed in contact with solid mixture; the second teardrop was in contact with the headspace gas only. The mixtures were loaded with nominally 0.5 wt % water under a helium atmosphere. Observations of corrosion ranged from superficial staining to pitting and SCC. The extent of corrosion depended on the total salt concentration and on the composition of the salt. The most significant corrosion was found in coupons that were exposed to 98 wt % PuO{sub 2}, 2 wt % chloride salt mixtures that contained calcium chloride. SCC was observed in two 304L stainless steel teardrop coupons exposed in solid contact to a mixture of 98 wt % PuO{sub 2}, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl{sub 2}. The cracking was associated with the heat-affected zone of an autogenous weld that ran across the center of the coupon. Cracking was not observed in coupons exposed to the headspace gas, nor in coupons exposed to other mixtures with either 0.92 wt% CaCl{sub 2} or no CaCl{sub 2}. The corrosion results point to the significance of the interaction between water loading and the concentration of the hydrating salt CaCl{sub 2} in the susceptibility of austenitic stainless steels to corrosion.

  16. Digital image correlation and infrared measurements to determine the influence of a uniaxial pre-strain on fatigue properties of a dual phase steel.

    NASA Astrophysics Data System (ADS)

    Munier, R.; Doudard, C.; Calloch, S.; Weber, B.

    2010-06-01

    The high cycle fatigue (HCF) is a major element for a great design of automotive parts. A wide part of the steel sheets for the automotive industry are stamped, sometimes deeply. During this operation, the steel is plastically strained in different directions, so that a good prediction of the fatigue behavior requires the determination of the fatigue properties of the pre-strained material. Nowadays, the evolution of HCF properties is often neglected, because of prohibitive time dedicated to traditional fatigue campaigns. To reduce the characterization time, self-heating measurements are used. This approach permits to identify the influence of homogeneous pre-strain on fatigue properties. The aim of this paper is to develop an original experimental test to identify this influence for a wide range of pre-strain with only one specimen. The study of a particular case of specimen with a constant gradient of pre-strain is presented. Digital image correlation is a way to determine the heterogeneity of the plastic pre-strain on the specimen and infrared measurements with a ”1D” approach allows the determination of the influence of a plastic pre-strain on the fatigue properties of the studied steel.

  17. Characterization of Stainless Steel and Refractory Metal Welds Made using a Diode-Pumped, Continuous Wave Nd: Yag Laser

    SciTech Connect

    Palmer, T A; Wood, B; Elmer, J W; Westrich, C; Milewski, J O; Piltch, M; Barbe, M; Carpenter, R

    2001-10-19

    A series of laser welds have been made on several materials using a Rofin-Sinar DY-033, 3.3 kW, Diode-Pumped Continuous Wave (CW) Nd:YAG laser system, located at Los Alamos National Laboratory. Materials welded in these experiments include 21-6-9 stainless steel, 304L stainless steel, vanadium, and tantalum. The effects of changes in the power input at a constant travel speed on the depth, width, aspect ratio, and total melted area of the welds have been analyzed. Increases in the measured weld pool dimensions as a function of power input are compared for each of the base metals investigated. These results provide a basis for further examining the characteristics of diode pumped CW Nd:YAG laser systems in welding applications.

  18. Crack growth rates of irradiated austenitic stainless steel weld heat affected zone in BWR environments.

    SciTech Connect

    Chopra, O. K.; Alexandreanu, B.; Gruber, E. E.; Daum, R. S.; Shack, W. J.; Energy Technology

    2006-01-31

    Austenitic stainless steels (SSs) are used extensively as structural alloys in the internal components of reactor pressure vessels because of their superior fracture toughness. However, exposure to high levels of neutron irradiation for extended periods can exacerbate the corrosion fatigue and stress corrosion cracking (SCC) behavior of these steels by affecting the material microchemistry, material microstructure, and water chemistry. Experimental data are presented on crack growth rates of the heat affected zone (HAZ) in Types 304L and 304 SS weld specimens before and after they were irradiated to a fluence of 5.0 x 10{sup 20} n/cm{sup 2} (E > 1 MeV) ({approx} 0.75 dpa) at {approx}288 C. Crack growth tests were conducted under cycling loading and long hold time trapezoidal loading in simulated boiling water reactor environments on Type 304L SS HAZ of the H5 weld from the Grand Gulf reactor core shroud and on Type 304 SS HAZ of a laboratory-prepared weld. The effects of material composition, irradiation, and water chemistry on growth rates are discussed.

  19. Fabrication of a simple materials system for study of Hg in a stainless steel.

    SciTech Connect

    Allen, C. W.

    1999-01-04

    The Spallation Neutron Source (SNS), currently under construction at Oak Ridge National Laboratory, is expected to employ a Hg target encased in a stainless steel. Little is known about the metallurgical behavior of this materials engineering system, which will occur in a service environment involving elevated temperatures and intense radiation. Under normal equilibrium conditions, however, Hg is known to be insoluble in and non-reactive with solid Fe and Cr but to form one or more intermetallics with Ni. Hg has been implanted into alloy 304L. For implantations at 400 and 500 C to a fluence of 3 x 10{sup 16} cm{sup {minus}2} sub-micron sized precipitates of Hg are formed, as judged, for example, from their solidification behavior on cooling during TEM observation. The formation of such a system of microtargets and possible studies employing them as in situ TEM specimens are discussed, which can provide useful empirical information in conjunction with SNS target development.

  20. Influence of Pre-straining and Heat Treatment on the Yield Surface of Precipitation Hardenable Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Lechner, Michael; Johannes, Maren; Kuppert, Andreas; Merklein, Marion

    Precipitation hardenable aluminum alloys are some of the most important lightweight materials. However, their range of applications in comparison to conventional deep drawing steels is limited by the low formability. Therefore, a new and innovative approach to enhance the formability of aluminum alloys in multistage forming operations was invented at the Institute of Manufacturing Technology, called intermediate heat treatment (IHT). Based on a short-term, laser-assisted heat treatment between two forming steps, it is possible to locally adapt the mechanical properties and realize an optimized strength distribution. For the successful application of the technology, the influence of the heat treatment on the mechanical properties has to be analyzed. Concerning the simulation of a multistage forming process, in particular, the yield surface of the material is very important. Within this paper, the influence of a combined pre-straining and a subsequent short-term, laser-assisted heat treatment on the yield surface will be presented.

  1. Low-Temperature Nitriding of Deformed Austenitic Stainless Steels with Various Nitrogen Contents Obtained by Prior High-Temperature Solution Nitriding

    NASA Astrophysics Data System (ADS)

    Bottoli, Federico; Winther, Grethe; Christiansen, Thomas L.; Dahl, Kristian Vinter; Somers, Marcel A. J.

    2016-08-01

    In the past decades, high nitrogen steels (HNS) have been regarded as substitutes for conventional austenitic stainless steels because of their superior mechanical and corrosion properties. However, the main limitation to their wider application is their expensive production process. As an alternative, high-temperature solution nitriding has been applied to produce HNS from three commercially available stainless steel grades (AISI 304L, AISI 316, and EN 1.4369). The nitrogen content in each steel alloy is varied and its influence on the mechanical properties and the stability of the austenite investigated. Both hardness and yield stress increase and the alloys remain ductile. In addition, strain-induced transformation of austenite to martensite is suppressed, which is beneficial for subsequent low-temperature nitriding of the surface of deformed alloys. The combination of high- and low-temperature nitriding results in improved properties of both bulk and surface.

  2. Gamma-ray irradiation effect on corrosion rates of stainless steel, Ti and Ti-5Ta in boiling 9N nitric acid

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takao; Tsukui, Shigeki; Okamoto, Shinichi; Nagai, Takayuki; Takeuchi, Masayuki; Takeda, Seiichiro; Tanaka, Yasumasa

    1996-03-01

    Irradiation effect of γ-rays on corrosion rates of stainless steel (type 304L), titanium and a titanium-tantalum alloy (Ti-5Ta) in 9N boiling nitric acid was investigated by measuring weight losses of specimens leached under a 60Co γ-ray environment of 1 kCkg -1/h (4 MR/h). Tests without irradiation were as well performed to obtain reference data. Plots of the weight loss normalized to specimen's surface area against total leaching time exhibited linear relations when the first leaching batch is neglected. The corrosion rates calculated from the gradients indicated slight, though significant, irradiation effects, an enhancement in stainless steel while suppressions in Ti and Ti-5Ta. Corrosion modes were found to be insensitive to the irradiation.

  3. 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.

  4. Deformation and cracking of irradiated austenitic stainless steels

    SciTech Connect

    Carter, R.D.; Atzmon, M.; Was, G.S.

    1995-12-31

    Samples of proton-irradiated 304L stainless steel were deformed by constant extension rate tensile tests at strain rates of 3 {times} 10{sup {minus}7} s{sup {minus}1} and 3 {times} 10{sup {minus}8} s{sup {minus}1} to strains of up to 10% at 288--350 C in argon. Minor cracking was observed in and around spinel inclusions in the material, however no intergranular cracking of the type observed in water environments was found. Thus intergranular cracking cannot occur by a radiation hardening mechanism alone. The microstructures that resulted from irradiation and deformation were characterized using electron microscopy. Surface slip band formation is observed on one or two {l_brace}111{r_brace} slip systems in each grain. The slip bands correspond to dislocation channels in the material as identified by transmission electron microscopy. The channels form by activation of grain-boundary dislocation sources, with the emitted dislocations sweeping through the grain interior to the opposing rain boundaries. During this process, the dislocations remove the radiation-produced defects. Slip band and dislocation channel densities increase with increasing strain in the samples. These results are used to interpret stress corrosion cracking behavior in this material.

  5. Tritium Effects on Fracture Toughness of Stainless Steel Weldments

    SciTech Connect

    MORGAN, MICHAEL; CHAPMAN, G. K.; TOSTEN, M. H.; WEST, S. L.

    2005-05-12

    The effects of tritium on the fracture toughness properties of Type 304L and Type 21-6-9 stainless steel weldments were measured. Weldments were tritium-charged-and-aged and then tested in order to measure the effect of the increasing decay helium content on toughness. The results were compared to uncharged and hydrogen-charged samples. For unexposed weldments having 8-12 volume percent retained delta ferrite, fracture toughness was higher than base metal toughness. At higher levels of weld ferrite, the fracture toughness decreased to values below that of the base metal. Hydrogen-charged and tritium-charged weldments had lower toughness values than similarly charged base metals and toughness decreased further with increasing weld ferrite content. The effect of decay helium content was inconclusive because of tritium off-gassing losses during handling, storage and testing. Fracture modes were dominated by the dimpled rupture process in unexposed weldments. In hydrogen and tritium-exposed weldments, the fracture modes depended on the weld ferrite content. At high ferrite contents, hydrogen-induced transgranular fracture of the weld ferrite phase was observed.

  6. 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.

  7. Twinning and martensite in a 304 austenitic stainless steel

    SciTech Connect

    Shen, Yongfeng; Li, Xi; Sun, Xin; Wang, Y. D.; Zuo, Liang

    2012-08-30

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

  8. Multilayer Mg-Stainless Steel Sheets, Twinning and Texture Evolution

    NASA Astrophysics Data System (ADS)

    Inoue, Junya; Sadeghi, Alireza; Ohmori, Toshinori; Koseki, Toshihiko

    2017-07-01

    In the present study, different combinations of multilayer sheets were prepared from 1 and 2 mm Mg AZ31 along with 0.25, 0.5, and 1 mm 304 L stainless steel. The texture and microstructure of the elongated samples (20 and 30 pct strain) were studied. It was found that the transversal stress plays an important role in both texture evolution and twinning in these composites. The obtained pole figures revealed an axial texture tilt with increasing steel layer volume fraction ( V f). It was found that this is a direct effect of transverse stress, which becomes more significant upon reducing Mg V f. This extra stress component tilts the basal planes away from the original normal direction in monolithic samples. Moreover, our results indicate that with decreasing Mg V f, twinning activity was increased in the 20 pct deformed samples but reduced in the samples with 30 pct elongation. It is known that at high strains where sufficient transverse stress is generated, the activity of prismatic slip is significantly enhanced, which promotes the motion of dislocations and reduces the necessity of twinning. With decreasing Mg V f, stronger transversal stress is generated and Mg reaches the critical threshold of prismatic activity at lower strains.

  9. 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.

  10. Stress corrosion cracking of austenitic stainless steel core internal welds.

    SciTech Connect

    Chung, H. M.; Park, J.-H.; Ruther, W. E.; Sanecki, J. E.; Strain, R. V.; Zaluzec, N. J.

    1999-04-14

    Microstructural analyses by several advanced metallographic techniques were conducted on austenitic stainless steel mockup and core shroud welds that had cracked in boiling water reactors. Contrary to previous beliefs, heat-affected zones of the cracked Type 304L, as well as 304 SS core shroud welds and mockup shielded-metal-arc welds, were free of grain-boundary carbides, which shows that core shroud failure cannot be explained by classical intergranular stress corrosion cracking. Neither martensite nor delta-ferrite films were present on the grain boundaries. However, as a result of exposure to welding fumes, the heat-affected zones of the core shroud welds were significantly contaminated by oxygen and fluorine, which migrate to grain boundaries. Significant oxygen contamination seems to promote fluorine contamination and suppress thermal sensitization. Results of slow-strain-rate tensile tests also indicate that fluorine exacerbates the susceptibility of irradiated steels to intergranular stress corrosion cracking. These observations, combined with previous reports on the strong influence of weld flux, indicate that oxygen and fluorine contamination and fluorine-catalyzed stress corrosion play a major role in cracking of core shroud welds.

  11. Effect of Pre-strain on the Solute Clustering, Mechanical Properties, and Work-Hardening of a Naturally Aged Al-Cu-Mg Alloy

    NASA Astrophysics Data System (ADS)

    Shao, D.; Zhang, P.; Zhang, J. Y.; Liu, G.; Wang, R. H.; Liu, W. Q.; Sha, G.; Sun, J.

    2017-09-01

    The effect of pre-strain on the solute clustering, mechanical properties, and work-hardening of a naturally aged Al-Cu-Mg alloy was comprehensively investigated using a three-dimensional atom probe, electrical resistivity, and hardness measurements. The pre-strain promoted the rapid formation of solute clusters but suppressed the growth of solute clusters during prolonged aging. An increase in pre-strain caused a decrease in the saturated number density of solute clusters, leading to a reduction in cluster strengthening. By taking into account the coupling effect of solute clusters and pre-existing dislocations, models were proposed to address the yield strength and work-hardening behaviors of the Al-Cu-Mg alloy, respectively. It reveals that the solute-cluster strengthening is comparable to dislocation strengthening in the naturally aged alloy. However, the work hardening is not significantly affected by the presence of the solute clusters. The findings reported in this paper will be helpful for the development of a naturally aged Al-Cu-Mg alloy with improved performance by controlling the pre-strain.

  12. Effect of Pre-strain on the Solute Clustering, Mechanical Properties, and Work-Hardening of a Naturally Aged Al-Cu-Mg Alloy

    NASA Astrophysics Data System (ADS)

    Shao, D.; Zhang, P.; Zhang, J. Y.; Liu, G.; Wang, R. H.; Liu, W. Q.; Sha, G.; Sun, J.

    2017-07-01

    The effect of pre-strain on the solute clustering, mechanical properties, and work-hardening of a naturally aged Al-Cu-Mg alloy was comprehensively investigated using a three-dimensional atom probe, electrical resistivity, and hardness measurements. The pre-strain promoted the rapid formation of solute clusters but suppressed the growth of solute clusters during prolonged aging. An increase in pre-strain caused a decrease in the saturated number density of solute clusters, leading to a reduction in cluster strengthening. By taking into account the coupling effect of solute clusters and pre-existing dislocations, models were proposed to address the yield strength and work-hardening behaviors of the Al-Cu-Mg alloy, respectively. It reveals that the solute-cluster strengthening is comparable to dislocation strengthening in the naturally aged alloy. However, the work hardening is not significantly affected by the presence of the solute clusters. The findings reported in this paper will be helpful for the development of a naturally aged Al-Cu-Mg alloy with improved performance by controlling the pre-strain.

  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. The Secret Life of Collagen: Temporal Changes in Nanoscale Fibrillar Pre-Strain and Molecular Organization during Physiological Loading of Cartilage.

    PubMed

    Inamdar, Sheetal R; Knight, David P; Terrill, Nicholas J; Karunaratne, Angelo; Cacho-Nerin, Fernando; Knight, Martin M; Gupta, Himadri S

    2017-08-17

    Articular cartilage is a natural biomaterial whose structure at the micro- and nanoscale is critical for healthy joint function and where degeneration is associated with widespread disorders such as osteoarthritis. At the nanoscale, cartilage mechanical functionality is dependent on the collagen fibrils and hydrated proteoglycans that form the extracellular matrix. The dynamic response of these ultrastructural building blocks at the nanoscale, however, remains unclear. Here we measure time-resolved changes in collagen fibril strain, using small-angle X-ray diffraction during compression of bovine and human cartilage explants. We demonstrate the existence of a collagen fibril tensile pre-strain, estimated from the D-period at approximately 1-2%, due to osmotic swelling pressure from the proteoglycan. We reveal a rapid reduction and recovery of this pre-strain which occurs during stress relaxation, approximately 60 s after the onset of peak load. Furthermore, we show that this reduction in pre-strain is linked to disordering in the intrafibrillar molecular packing, alongside changes in the axial overlapping of tropocollagen molecules within the fibril. Tissue degradation in the form of selective proteoglycan removal disrupts both the collagen fibril pre-strain and the transient response during stress relaxation. This study bridges a fundamental gap in the knowledge describing time-dependent changes in collagen pre-strain and molecular organization that occur during physiological loading of articular cartilage. The ultrastructural details of this transient response are likely to transform our understanding of the role of collagen fibril nanomechanics in the biomechanics of cartilage and other hydrated soft tissues.

  15. 2016 Accomplishments. Tritium aging studies on stainless steel. Forging process effects on the fracture toughness properties of tritium-precharged stainless steel

    SciTech Connect

    Morgan, Michael J.

    2017-01-01

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

  16. Impact Tensile Testing of Stainless Steels at Various Temperatures

    SciTech Connect

    D. K. Morton

    2008-03-01

    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 during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern (1 to 300 per second) are not well documented. However, research is being performed at the Idaho National Laboratory to quantify these characteristics. The work presented herein discusses tensile impact testing of dual-marked 304/304L and 316/316L stainless steel material specimens. Both base material and welded material specimens were tested at -20 oF, room temperature, 300 oF, and 600 oF conditions. Utilizing a drop weight impact test machine and 1/4-inch and 1/2-inch thick dog bone-shaped test specimens, a strain rate range of approximately 4 to 40 per second (depending on initial temperature conditions) was achieved. Factors were determined that reflect the amount of increased strain energy the material can absorb due to strain rate effects. Using the factors, elevated true stress-strain curves for these materials at various strain rates and temperatures were generated. By incorporating the strain rate elevated true stress-strain material curves into an inelastic finite element computer program as the defined material input, significant improvement in the accuracy of the computer analyses was attained. However, additional impact testing is necessary to achieve higher strain rates (up to 300 per second) before complete definition of strain rate effects can be made for accidental drop events and other similar energy-limited impulsive loads. This research approach, using impact testing and a total energy analysis methodology to quantify strain rate effects, can be applied to many other materials used in government and industry.

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

    NASA Astrophysics Data System (ADS)

    Switzner, Nathan

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

  18. The effects of 800 MeV proton irradiation on the corrosion of tungsten, tantalum, stainless steel, and gold

    SciTech Connect

    Lillard, R.S.; Butt, D.P.; Kanner, G.; Daemen, L.

    1997-12-01

    Real time electrochemical data were acquired for tungsten, tantalum, stainless steel 304L, and gold targets during proton irradiation at the LANSCE Weapons Neutron Research Facility. The goal of this research was to establish a better understanding of the corrosion properties of materials as a function of proton irradiation and gain insight into the mechanism of the observed phenomena. The following electrochemical observations were made during proton irradiation of W, Ta, SS304, and Au: (1) the open circuit potential of all materials increased with increasing proton fluence; (2) the corrosion rate (at the OCP) of W and SS304 increased with increasing proton fluence; (3) the passive dissolution rate for SS304 and Ta decreased with increasing proton fluence; (4) the anodic dissolution rate for W increased with increasing proton fluence; (5) the pitting potential for SS304 increased with proton fluence, which is an indication that the material is less susceptible to pitting attack during irradiation.

  19. 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.

  20. 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.

  1. Corrosion experiments on stainless steels used in dry storage canisters of spent nuclear fuel

    SciTech Connect

    Ryskamp, J.M.; Adams, J.P.; Faw, E.M.; Anderson, P.A.

    1996-09-01

    Nonradioactive (cold) experiments have been set up in the Idaho Chemical Processing Plant (ICPP)-1634, and radioactive (hot) experiments have been set up in the Irradiated Fuel Storage Facility (IFSF) at ICPP. The objective of these experiments is to provide information on the interactions (corrosion) between the spent nuclear fuel currently stored at the ICPP and the dry storage canisters and containment materials in which this spent fuel will be stored for the next several decades. This information will be used to help select canister materials that will retain structural integrity over this period within economic, criticality, and other constraints. The two purposes for Dual Purpose Canisters (DPCs) are for interim storage of spent nuclear fuel and for shipment to a final geological repository. Information on how corrosion products, sediments, and degraded spent nuclear fuel may corrode DPCs will be required before the DPCs will be allowed to be shipped out of the State of Idaho. The information will also be required by the Nuclear Regulatory Commission (NRC) to support the licensing of DPCs. Stainless steels 304L and 316L are the most likely materials for dry interim storage canisters. Welded stainless steel coupons are used to represent the canisters in both hot and cold experiments.

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

    NASA Technical Reports Server (NTRS)

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

    2017-01-01

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

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

    PubMed

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

    2017-03-22

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

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

    PubMed Central

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

    2017-01-01

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

  5. Antibacterial silver nanocluster/silica composite coatings on stainless steel

    NASA Astrophysics Data System (ADS)

    Ferraris, M.; Perero, S.; Ferraris, S.; Miola, M.; Vernè, E.; Skoglund, S.; Blomberg, E.; Odnevall Wallinder, I.

    2017-02-01

    A coating made of silver nanocluster/silica composites has been deposited, via a radio frequency (RF) co-sputtering technique, for the first time onto stainless steel (AISI 304L) with the aim to improve its antibacterial properties. Different thermal treatments after coating deposition have been applied in order to optimize the coating adhesion, cohesion and its antibacterial properties. Its applicability has been investigated at realistic conditions in a cheese production plant. The physico-chemical characteristics of the coatings have been analyzed by means of different bulk and surface analytical techniques. Field emission scanning electron microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM) were employed to assess coating morphology, composition, surface roughness, wetting properties, size and local distribution of the nanoparticles within the coating. Tape tests were used to determine the adhesion/cohesion properties of the coating. The amount and time-dependence of released silver in solutions of acetic acid, artificial water, artificial tap water and artificial milk were determined by means of Atomic Absorption Spectroscopy (AAS). The antibacterial effect of the coating was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus in compliance with National Committee for Clinical Laboratory Standards (NCCLS) and AATCC 147 standards. The Ahearn test was performed to measure the adhesion of bacteria to the coated stainless steel surface compared with a control surface. The antibacterial coating retained its antibacterial activity after thermal treatment up to 450 °C and after soaking in common cleaning products for stainless steel surfaces used for e.g. food applications. The antibacterial capacity of the coating remained at high levels for 1-5 days, and showed a good capacity to reduce the adhesion of bacteria up to 30 days. Only a few

  6. 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.

  7. Isolation of the role of radiation-induced segregation in irradiation-assisted stress corrosion cracking of proton-irradiated austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Busby, Jeremy Todd

    2001-11-01

    The role of radiation-induced segregation (RIS) in irradiation-assisted stress corrosion cracking (IASCC) was studied in order to better understand the underlying mechanisms of IASCC. High-purity 304L (HP-304L), commercial purity 304 (CP-304) and commercial purity 316 (CP-316) stainless steel alloys were irradiated with 3.2 MeV protons at 400°C (HP-304L) and 360°C (CP-304 and CP-316) to doses ranging from 0.1 and 5.0 dpa. Grain boundary chemistry was measured using scanning transmission electron microscopy with energy-dispersive spectroscopy (STEM/EDS) in both unirradiated and irradiated samples. Unirradiated and irradiated samples of the two commercial purity alloys were also strained to failure in an aqueous environment representative of boiling water reactor cores. The cracking susceptibility and RIS in the proton-irradiated CP-304 is very similar to that from the neutron-irradiated samples. The CP-316 alloy did not crack. Radiation-induced segregation, cracking susceptibility, and dislocation loop microstructure developed at the same rate as a function of dose in the CP-304 alloy. To isolate the effects of RIS in IASCC, post-irradiation annealing was utilized. Simulations of post-irradiation annealing of RIS and dislocation loop microstructure show that dislocation loops are removed preferentially over RIS due to the density of vacancies required and kinetic considerations. Experimental anneals were conducted on HP-304L samples irradiated to 1.0 dpa and CP-304 samples irradiated to 1.0 and 2.5 dpa. Post-irradiation anneals were performed at temperatures ranging from 400°C to 650°C for times between 45 minutes and 5 hours. At all temperatures, the hardness and dislocation densities decreased with increasing annealing time much faster than RIS did. Annealing at 600°C for 90 minutes removed virtually all dislocation microstructure while leaving RIS intact. Cracking susceptibility in the CP-304 alloy was mitigated rapidly during post-irradiation annealing

  8. 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.

  9. 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.

  10. Weld solidification cracking in 304 to 204L stainless steel

    SciTech Connect

    Hochanadel, Patrick W; Lienert, Thomas J; Martinez, Jesse N; Johnson, Matthew Q

    2010-09-15

    A series of annulus welds were made between 304 and 304L stainless steel coaxial tubes using both pulsed laser beam welding (LBW) and pulsed gas tungsten arc welding (GTAW). In this application, a change in process from pulsed LBW to pulsed gas tungsten arc welding was proposed to limit the possibility of weld solidification cracking since weldability diagrams developed for GTAW display a greater range of compositions that are not crack susceptible relative to those developed for pulsed LBW. Contrary to the predictions of the GTAW weldability diagram, cracking was found.This result was rationalized in terms of the more rapid solidification rate of the pulsed gas tungsten arc welds. In addition, for the pulsed LBW conditions, the material compositions were predicted to be, by themselves, 'weldable' according to the pulsed LBW weldability diagram. However, the composition range along the tie line connecting the two compositions passed through the crack susceptible range. Microstructurally, the primary solidification mode (PSM) of the material processed with higher power LBW was determined to be austenite (A), while solidification mode of the materials processed with lower power LBW apparently exhibited a dual PSM of both austenite (A) and ferrite-austenite (FA) within the same weld. The materials processed by pulsed GTAW showed mostly primary austenite solidification, with some regions of either primary austenite-second phase ferrite (AF) solidification or primary ferrite-second phase austenite (FA) solidification. This work demonstrates that variations in crack susceptibility may be realized when welding different heats of 'weldable' materials together, and that slight variations in processing can also contribute to crack susceptibility.

  11. Sensitization of stainless steel

    NASA Technical Reports Server (NTRS)

    Nagy, James P.

    1990-01-01

    The objective of this experiment is to determine the corrosion rates of 18-8 stainless steels that have been sensitized at various temperatures and to show the application of phase diagrams. The laboratory instructor will assign each student a temperature, ranging from 550 C to 1050 C, to which the sample will be heated. Further details of the experimental procedure are detailed.

  12. High Nitrogen Stainless Steel

    DTIC Science & Technology

    2011-07-19

    Hydrogen Embrittlement in Steel by the Increment Loading Technique. Fractography: After the stress-life fatigue tests, the fracture surface morphology...study was conducted to clarify the mechanical properties and stress corrosion cracking (SCC) resistance of high nitrogen stainless steel (HNSS) plates...Corrosion Cracking 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON

  13. Welding of Stainless Materials

    NASA Technical Reports Server (NTRS)

    Bull, H; Johnson, Lawrence

    1929-01-01

    It would appear that welds in some stainless steels, heat-treated in some practicable way, will probably be found to have all the resistance to corrosion that is required for aircraft. Certainly these structures are not subjected to the severe conditions that are found in chemical plants.

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

    DOE PAGES

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

    2017-01-31

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

  15. Size-dependent plasticity in KCl and LiF single crystals: influence of orientation, temperature, pre-straining and doping

    NASA Astrophysics Data System (ADS)

    Zou, Yu; Spolenak, Ralph

    2015-06-01

    Size effects in plasticity are mostly studied in metallic systems, but they are rarely investigated in ionic crystals. In this study, single-crystalline KCl and LiF pillars were fabricated by focused ion beam technique and compressed using a flat punch tip in a nanoindenter. The materials were investigated with regards to crystal orientation, test temperature, pre-straining and doping. The results show: (1) [1 1 1] LiF pillars do exhibit size effect with an exponent of -0.38, in contrary to no size effect in [1 1 1] LiF reported in literature; (2) [0 0 1] LiF, and [0 0 1] and [1 1 1] KCl have similar size-effect exponents of -0.68, -0.71 and -0.65, respectively; (3) the size effect of [1 1 1] LiF pillars is more sensitive to the temperature change than that of [0 0 1] LiF pillars; (4) pre-straining of [1 1 1] LiF pillars results in a reduced size effect; (5) the 0.05 mol% CaCl2 doping in [0 0 1] KCl slightly increases strength levels and does not change the size effect much. The magnitude of the size effects in ionic crystals can be attributed to the bulk stress level, but not the slip systems. In addition, a correlation between critical temperatures and size-effect slopes is illustrated, and the additivity of strengthening mechanisms is critically discussed.

  16. Relative Humidity and the Susceptibility of Austenitic Stainless Steel to Stress Corrosion Cracking in an impure Plutonium Oxide Environment

    SciTech Connect

    Zapp, P.; Duffey, J.; Lam, P.; Dunn, K.

    2010-05-05

    Laboratory tests to investigate the corrosivity of moist plutonium oxide/chloride salt mixtures on 304L and 316L stainless steel coupons showed that corrosion occurred in selected samples. The tests exposed flat coupons for pitting evaluation and 'teardrop' stressed coupons for stress corrosion cracking (SCC) evaluation at room temperature to various mixtures of PuO{sub 2} and chloride-bearing salts for periods up to 500 days. The exposures were conducted in sealed containers in which the oxide-salt mixtures were loaded with about 0.6 wt % water from a humidified helium atmosphere. Observations of corrosion ranged from superficial staining to pitting and SCC. The extent of corrosion depended on the total salt concentration, the composition of the salt and the moisture present in the test environment. The most significant corrosion was found in coupons that were exposed to 98 wt % PuO{sub 2}, 2 wt % chloride salt mixtures that contained calcium chloride and 0.6 wt% water. SCC was observed in two 304L stainless steel teardrop coupons exposed in solid contact to a mixture of 98 wt % PuO{sub 2}, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl{sub 2}. The cracking was associated with the heat-affected zone of an autogenous weld that ran across the center of the coupon. Cracking was not observed in coupons exposed to the headspace gas above the solid mixture, or in coupons exposed to other mixtures with either no CaCl{sub 2} or 0.92 wt% CaCl{sub 2}. SCC was present where the 0.6 wt % water content exceeded the value needed to fully hydrate the available CaCl{sub 2}, but was absent where the water content was insufficient. These results reveal the significance of the relative humidity in the austenitic stainless steels environment to their susceptibility to corrosion. The relative humidity in the test environment was controlled by the water loading and the concentration of the hydrating salts such as CaCl{sub 2}. For each salt or salt mixture there is a threshold relative

  17. The Spatiotemporal Control of Osteoblast Cell Growth, Behavior, and Function Dictated by Nanostructured Stainless Steel Artificial Microenvironments.

    PubMed

    Dhawan, Udesh; Pan, Hsu-An; Shie, Meng-Je; Chu, Ying Hao; Huang, Guewha S; Chen, Po-Chun; Chen, Wen Liang

    2017-12-01

    The successful application of a nanostructured biomaterial as an implant is strongly determined by the nanotopography size triggering the ideal cell response. Here, nanoporous topography on 304L stainless steel substrates was engineered to identify the nanotopography size causing a transition in the cellular characteristics, and accordingly, the design of nanostructured stainless steel surface as orthopedic implants is proposed. A variety of nanopore diameters ranging from 100 to 220 nm were fabricated by one-step electrolysis process and collectively referred to as artificial microenvironments. Control over the nanopore diameter was achieved by varying bias voltage. MG63 osteoblasts were cultured on the nanoporous surfaces for different days. Immunofluorescence (IF) and scanning electron microscopy (SEM) were performed to compare the modulation in cell morphologies and characteristics. Osteoblasts displayed differential growth parameters and distinct transition in cell behavior after nanopore reached a certain diameter. Nanopores with 100-nm diameter promoted cell growth, focal adhesions, cell area, viability, vinculin-stained area, calcium mineralization, and alkaline phosphatase activity. The ability of these nanoporous substrates to differentially modulate the cell behavior and assist in identifying the transition step will be beneficial to biomedical engineers to develop superior implant geometries, triggering an ideal cell response at the cell-nanotopography interface.

  18. Examination of stainless steel-clad Connecticut Yankee fuel assembly S004 after storage in borated water

    SciTech Connect

    Langstaff, D.C.; Bailey, W.J.; Johnson, A.B. Jr.; Landow, M.P.; Pasupathi, V.; Klingensmith, R.W.

    1982-09-01

    A Connecticut Yankee fuel assembly (S004) was tested nondestructively and destructively. It was concluded that no obvious degradation of the 304L stainless steel-clad spent fuel from assembly S004 occurred during 5 y of storage in borated water. Furthermore, no obvious degradation due to the pool environment occurred on 304 stainless steel-clad rods in assemblies H07 and G11, which were stored for shorter periods but contained operationally induced cladding defects. The seam welds in the cladding on fuel rods from assembly S004, H07, and G11 were similar in that they showed a wrought microstructure with grains noticeably smaller than those in the cladding base metal. The end cap welds showed a dendritically cored structure, typical of rapidly quenched austenitic weld metal. Some intergranular melting may have occurred in the heat-affected zone (HAZ) in the cladding adjacent to the end cap welds in rods from assemblies S004 and H07. However, the weld areas did not show evidence of corrosion-induced degradation.

  19. Size-separated particle fractions of stainless steel welding fume particles - A multi-analytical characterization focusing on surface oxide speciation and release of hexavalent chromium.

    PubMed

    Mei, N; Belleville, L; Cha, Y; Olofsson, U; Odnevall Wallinder, I; Persson, K-A; Hedberg, Y S

    2017-08-31

    Welding fume of stainless steels is potentially health hazardous. The aim of this study was to investigate the manganese (Mn) and chromium (Cr) speciation of welding fume particles and their extent of metal release relevant for an inhalation scenario, as a function of particle size, welding method (manual metal arc welding, metal arc welding using an active shielding gas), different electrodes (solid wires and flux-cored wires) and shielding gases, and base alloy (austenitic AISI 304L and duplex stainless steel LDX2101). Metal release investigations were performed in phosphate buffered saline (PBS), pH 7.3, 37°, 24h. The particles were characterized by means of microscopic, spectroscopic, and electroanalytical methods. Cr was predominantly released from particles of the welding fume when exposed in PBS [3-96% of the total amount of Cr, of which up to 70% as Cr(VI)], followed by Mn, nickel, and iron. Duplex stainless steel welded with a flux-cored wire generated a welding fume that released most Cr(VI). Nano-sized particles released a significantly higher amount of nickel compared with micron-sized particle fractions. The welding fume did not contain any solitary known chromate compounds, but multi-elemental highly oxidized oxide(s) (iron, Cr, and Mn, possibly bismuth and silicon). Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  20. Angle-dependent lubricated tribological properties of stainless steel by femtosecond laser surface texturing

    NASA Astrophysics Data System (ADS)

    Wang, Zhuo; Li, Yang-Bo; Bai, Feng; Wang, Cheng-Wei; Zhao, Quan-Zhong

    2016-07-01

    Lubricated tribological properties of stainless steel were investigated by femtosecond laser surface texturing. Regular-arranged micro-grooved textures with different spacing and micro-groove inclination angles (between micro-groove path and sliding direction) were produced on AISI 304L steel surfaces by an 800 nm femtosecond laser. The spacing of micro-groove was varied from 25 to 300 μm, and the inclination angles of micro-groove were measured as 90° and 45°. The tribological properties of the smooth and textured surfaces with micro-grooves were investigated by reciprocating ball-on-flat tests against Al2O3 ceramic balls under starved oil lubricated conditions. Results showed that the spacing of micro-grooves significantly affected the tribological property. With the increase of micro-groove spacing, the average friction coefficients and wear rates of textured surfaces initially decreased then increased. The tribological performance also depended on the inclination angles of micro-grooves. Among the investigated patterns, the micro-grooves perpendicular to the sliding direction exhibited the lowest average friction coefficient and wear rate to a certain extent. Femtosecond laser-induced surface texturing may remarkably improve friction and wear properties if the micro-grooves were properly distributed.

  1. High stored-energy breakdown tests on electrodes made of stainless steel, copper, titanium and molybdenum

    NASA Astrophysics Data System (ADS)

    de Esch, H. P. L.; Simonin, A.; Grand, C.

    2015-04-01

    IRFM have conducted resilience tests on electrodes made of Cu, stainless steel 304L, Ti and Mo against breakdowns up to 170 kV and 300 J. The tests of the 10×10 cm2 electrodes have been performed at an electrode distance d=11 mm under vacuum (P˜5×10-6 mbar). No great difference in voltage holding between the materials could be identified; all materials could reach a voltage holding between 140 and 170 kV over the 11 mm gap, i.e. results scatter within a ±10% band. After exposure to ˜10000 seconds of high-voltage (HV) on-time, having accumulated ˜1000 breakdowns, the electrodes were inspected. The anodes were covered with large and small craters. The rugosity of the anodes had increased substantially, that of the cathodes to a lesser extent. The molybdenum electrodes are least affected, but this does not show in their voltage holding capability. It is hypothesized that penetrating high-energy electrons from the breakdown project heat below the surface of the anode and cause a micro-explosion of material when melting point is exceeded. Polished electrodes have also been tested. The polishing results in a substantially reduced breakdown rate in the beginning, but after having suffered a relatively small number (˜100) of breakdowns, the polished electrodes behaved the same as the unpolished ones.

  2. Upset Resistance Welding of Carbon Steel to Austenitic Stainless Steel Narrow Rods

    NASA Astrophysics Data System (ADS)

    Ozlati, Ashkaan; Movahedi, Mojtaba; Mohammadkamal, Helia

    2016-11-01

    Effects of welding current (at the range of 2-4 kA) on the microstructure and mechanical properties of upset resistance welds of AISI-1035 carbon steel to AISI-304L austenitic stainless steel rods were investigated. The results showed that the joint strength first increased by raising the welding current up to 3 kA and then decreased beyond it. Increasing trend was related to more plastic deformation, accelerated diffusion, reduction of defects and formation of mechanical locks at the joint interface. For currents more than 3 kA, decrease in the joint strength was mainly caused by formation of hot spots. Using the optimum welding current of 3 kA, tensile strength of the joint reached to 76% of the carbon steel base metal strength. Microstructural observations and microhardness results confirmed that there was no hard phase, i.e., martensite or bainite, at the weld zone. Moreover, a fully austenitic transition layer related to carbon diffusion from carbon steel was observed at the weld interface.

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

    NASA Astrophysics Data System (ADS)

    Stephenson, Kale J.; Was, Gary S.

    2016-12-01

    This study intended to understand how dislocation channeling affects IASCC initiation using a novel four-point bend test. Stainless steels used in this study (irradiated in the BOR-60 reactor) included a commercial purity 304L alloy irradiated to 5.5, 10.2, and 47.5 dpa, and two high purity alloys, Fesbnd 18Crsbnd 12Ni and Fesbnd 18Crsbnd 25Ni, irradiated to ∼10 dpa. IASCC was enhanced by MnS inclusions, which dissolve in the NWC environment and form oxide caps, creating a crevice condition with a high propensity for crack initiation. Stress concentration at the grain boundary intersecting these sites induced crack initiation, resulting from discontinuous dislocation channels (DC). Stress to initiate IASCC decreased with dose due to earlier DC initiation. The HP Fesbnd 18Crsbnd 12Ni alloy had low IASCC susceptibility and the high Ni alloy did not crack. The difference was attributed to the propensity for DCs to transmit across grain boundaries, which controls stress accumulation at DC - grain boundary intersections.

  4. Microstructure and Interfacial Reactions During Active Metal Brazing of Stainless Steel to Titanium

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    Microstructural evolution and interfacial reactions during active metal vacuum brazing of Ti (grade-2) and stainless steel (SS 304L) using a Ag-based alloy containing Cu, Ti, and Al was investigated. A Ni-depleted solid solution layer and a discontinuous layer of (Ni,Fe)2TiAl intermetallic compound formed on the SS surface and adjacent to the SS-braze alloy interface, respectively. Three parallel contiguous layers of intermetallic compounds, CuTi, AgTi, and (Ag,Cu)Ti2, formed at the Ti-braze alloy interface. The diffusion path for the reaction at this interface was established. Transmission electron microscopy revealed formation of nanocrystals of Ag-Cu alloy of size ranging between 20 and 30 nm in the unreacted braze alloy layer. The interdiffusion zone of β-Ti(Ag,Cu) solid solution, formed on the Ti side of the joint, showed eutectoid decomposition to lamellar colonies of α-Ti and internally twinned (Cu,Ag)Ti2 intermetallic phase, with an orientation relationship between the two. Bend tests indicated that the failure in the joints occurred by formation and propagation of the crack mostly along the Ti-braze alloy interface, through the (Ag,Cu)Ti2 phase layer.

  5. High stored-energy breakdown tests on electrodes made of stainless steel, copper, titanium and molybdenum

    SciTech Connect

    Esch, H. P. L. de Simonin, A.; Grand, C.

    2015-04-08

    IRFM have conducted resilience tests on electrodes made of Cu, stainless steel 304L, Ti and Mo against breakdowns up to 170 kV and 300 J. The tests of the 10×10 cm{sup 2} electrodes have been performed at an electrode distance d=11 mm under vacuum (P∼5×10{sup −6} mbar). No great difference in voltage holding between the materials could be identified; all materials could reach a voltage holding between 140 and 170 kV over the 11 mm gap, i.e. results scatter within a ±10% band. After exposure to ∼10000 seconds of high-voltage (HV) on-time, having accumulated ∼1000 breakdowns, the electrodes were inspected. The anodes were covered with large and small craters. The rugosity of the anodes had increased substantially, that of the cathodes to a lesser extent. The molybdenum electrodes are least affected, but this does not show in their voltage holding capability. It is hypothesized that penetrating high-energy electrons from the breakdown project heat below the surface of the anode and cause a micro-explosion of material when melting point is exceeded. Polished electrodes have also been tested. The polishing results in a substantially reduced breakdown rate in the beginning, but after having suffered a relatively small number (∼100) of breakdowns, the polished electrodes behaved the same as the unpolished ones.

  6. The Effect of Microstructure and Pre-strain on the Change in Apparent Young's Modulus of a Dual-Phase Steel

    NASA Astrophysics Data System (ADS)

    Kupke, A.; Hodgson, P. D.; Weiss, M.

    2017-07-01

    The elastic recovery in dual-phase (DP) steels is not a linear process and changes with plastic deformation. The level of change in the apparent Young's modulus has been reported to depend on material composition and microstructure, but most previous experimental studies were limited to industrial DP steels and led to contradicting results. This work represents a first fundamental study that investigates the separate and combined effect of phase volume fraction and hardness on the change in apparent Young's modulus in DP steel. A common automotive DP steel (DP780) is heat treated to obtain seven different combinations of martensite and ferrite volume fraction and hardness while keeping the chemical composition as well as the shape of the martensite and ferrite phases unchanged. Loading-unloading tests were performed to analyze the chord modulus at various levels of pre-strain. The results suggest that the point of saturation of the chord modulus with pre-strain depends on the morphology of the microstructure, occurring earlier for microstructures consisting of ferrite grains surrounded by martensite laths. It is further revealed that the reduction of the apparent Young's modulus, which is the difference between the material's initial Young's modulus and the chord modulus, increases with martensite hardness if the martensite volume fraction is kept constant. A higher martensite volume fraction initially elevates the reduction of the apparent Young's modulus. After a critical volume fraction of martensite phase of 35%, a decrease in apparent Young's modulus reduction was observed. A comparison of the plastic unloading strain suggests that the mechanisms leading to a reduction in apparent Young's modulus are strongest for the microstructure consisting of 35% martensite volume fraction.

  7. The effect of pre-straining and pre-ageing on a novel thermomechanical treatment for improving the mechanical properties of AA2139 aerospace aluminium alloys

    NASA Astrophysics Data System (ADS)

    Bakare, F.; Alsubhi, Y.; Ragkousis, A.; Ebomwonyi, O.; Damisa, J.; Okunzuwa, S.

    2017-07-01

    The novel thermomechanical treatment employed by Wang Z et al (2014 Mater. Sci. Eng. A 607 313-7) in enhancing the mechanical and microstructure properties of 6000 series aluminium alloys has been replicated for AA2139 aerospace aluminium alloys. The novel route which involves under-ageing, cold-rolling reductions and re-ageing at a fixed temperature has been carried out focusing on the effect of pre-straining and pre-ageing on the alloy properties. The influence of varying cold-rolling reductions and pre-ageing has been examined by tensile testing, hardness testing, differential scanning calorimetry, thermoelectric power measurements and scanning electron microscope (SEM). Further analyses were conducted with DSC and TEP measurements to check for precipitation sequence and solute retention respectively. On comparing the hardness and strength of the non pre-aged to the pre-aged samples, there is a remarkable increase in the hardness and strength of the aerospace alloy showing the huge influence of both pre-ageing and pre-straining stage of the novel thermomechanical treatment as observed in the 6000 series alloy, albeit at a higher rate. The treatments that exhibited the most promising mechanical properties (hardness, yield and ultimate tensile strength, elongation to failure) were found to be at a pre-ageing temperature of 175 °C for 1.5 h, 40% cold-rolling and re-ageing at 150 °C. The material was found to have yield strength of 590 MPa and 8.1% uniform elongation, which is well above the 5% acceptable value for structural applications and with strength levels adaptable for aerospace industries. The presence of higher volume fraction of well dispersed precipitates observed in the SEM further shows that intermediate cold-rolling reductions combines well with pre-ageing to give the best mechanical properties in this alloy.

  8. The Effect of Heat Treatments and Coatings on the Outgassing Rate of Stainless Steel Chambers

    SciTech Connect

    Mamum, Md Abdullah A.; Elmustafa, Abdelmageed A,; Stutzman, Marcy L.; Adderley, Philip A.; Poelker, Matthew

    2014-03-01

    The outgassing rates of four nominally identical 304L stainless steel vacuum chambers were measured to determine the effect of chamber coatings and heat treatments. One chamber was coated with titanium nitride (TiN) and one with amorphous silicon (a-Si) immediately following fabrication. One chamber remained uncoated throughout, and the last chamber was first tested without any coating, and then coated with a-Si following a series of heat treatments. The outgassing rate of each chamber was measured at room temperatures between 15 and 30 deg C following bakes at temperatures between 90 and 400 deg C. Measurements for bare steel showed a significant reduction in the outgassing rate by more than a factor of 20 after a 400 deg C heat treatment (3.5 x 10{sup 12} TorrL s{sup -1}cm{sup -2} prior to heat treatment, reduced to 1.7 x 10{ sup -13} TorrL s{sup -1}cm{sup -2} following heat treatment). The chambers that were coated with a-Si showed minimal change in outgassing rates with heat treatment, though an outgassing rate reduced by heat treatments prior to a-Si coating was successfully preserved throughout a series of bakes. The TiN coated chamber exhibited remarkably low outgassing rates, up to four orders of magnitude lower than the uncoated stainless steel. An evaluation of coating composition suggests the presence of elemental titanium which could provide pumping and lead to an artificially low outgassing rate. The outgassing results are discussed in terms of diffusion-limited versus recombination-limited processes.

  9. Stainless steel decontamination manipulators

    SciTech Connect

    Sullivan, R.J.

    1986-01-01

    Three, large-volume coverage manipulator systems were designed and built for the Defense Water Processing Facility at the Savannah River Laboratory. These stainless steel systems will be used for high-pressure spray decontamination of waste containers and large process equipment modules. Each system has a manipulator arm, folding boom, and vertical drive and guide structure. Handling capacity is 45 kg, horizontal reach is 4.6 m with a 180-deg swing motion, and the vertical travel is 6 m. The system is remotely removable and replaceable in modules using an overhead crane and an impact wrench. The manipulator arm has seven motions: Shoulder rotation and pivot, elbow pivot, wrist pivot and rotation, and grip open-close. All motions are variable speed and are slip-clutch protected to prevent overloading from external forces (collisions).

  10. 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.

  11. Brazing titanium to stainless steel

    NASA Technical Reports Server (NTRS)

    Batista, R. I.

    1980-01-01

    Titanium and stainless-steel members are usually joined mechanically for lack of any other effective method. New approach using different brazing alloy and plating steel member with nickel resolves problem. Process must be carried out in inert atmosphere.

  12. Determination of creep compliance and creep-swelling coupling coefficients for neutron-irradiated titanium-modified stainless steel at @400 degree C

    SciTech Connect

    Toloczko, M.B. ); Garner, F.A. ); Eiholzer, C.R. )

    1991-11-01

    Irradiation creep data from FFTF-MOTA at {approximately}400{degrees}C were analyzed for nine 20% cold-worked titanium-modified type 316 stainless steels, each of which exhibits a different duration for the transient regime of swelling. One of these steels was the fusion prime candidate alloy designated PCA. The others were various developmental breeder reactor heats. The analysis was based on the assumption that the B{sub 0} + DS creep model applies to these steels at this temperature. This assumption was found to be valid. A creep-swelling coupling coefficient of D {approx} 0.6 {times} 10{sup {minus}2} MPa{sup {minus}1} was found for all steels that had developed a significant level of swelling. This result is in excellent agreement with the results of earlier studies conducted in EBR-II using annealed AISI 304L and also 10% and 20% cold-worked AISI 316 stainless steels. There appears to be some enhancement of swelling by stress, contradicting an important assumption in the analysis and leading to an apparent but misleading nonlinearity of creep with respect to stress.

  13. Determination of creep compliance and creep-swelling coupling coefficients for neutron-irradiated titanium-modified stainless steel at {approximately}400{degree}C

    SciTech Connect

    Toloczko, M.B.; Garner, F.A.; Eiholzer, C.R.

    1991-11-01

    Irradiation creep data from FFTF-MOTA at {approximately}400{degrees}C were analyzed for nine 20% cold-worked titanium-modified type 316 stainless steels, each of which exhibits a different duration for the transient regime of swelling. One of these steels was the fusion prime candidate alloy designated PCA. The others were various developmental breeder reactor heats. The analysis was based on the assumption that the B{sub 0} + DS creep model applies to these steels at this temperature. This assumption was found to be valid. A creep-swelling coupling coefficient of D {approx} 0.6 {times} 10{sup {minus}2} MPa{sup {minus}1} was found for all steels that had developed a significant level of swelling. This result is in excellent agreement with the results of earlier studies conducted in EBR-II using annealed AISI 304L and also 10% and 20% cold-worked AISI 316 stainless steels. There appears to be some enhancement of swelling by stress, contradicting an important assumption in the analysis and leading to an apparent but misleading nonlinearity of creep with respect to stress.

  14. Laser-induced fluorescence applied to laser welding of austenitic stainless steel for dilute alloying element detection

    NASA Astrophysics Data System (ADS)

    Simonds, Brian J.; Sowards, Jeffrey W.; Williams, Paul A.

    2017-08-01

    Optical spectral analysis of the laser weld plume is a common technique for non-contact, in situ weld plume analysis. However, the low sensitivity of optical emission spectroscopy limits the available information during 1070 nm wavelength laser welding, which is becoming the standard in many industrial operations. Here we demonstrate an improved sensitivity of optical spectroscopy by applying laser-induced fluorescence (LIF) for probing the hot gas plume induced during fiber laser welding of 304L austenitic stainless steel. As a proof-of-principle, we show that LIF is capable of resolving a spectral signal from silicon being emitted during welding. Optical detection of such a low concentration alloying element has not previously been reported and shows the capability of LIF for increased sensitivity. Silicon atoms in the weld plume were excited in the ultraviolet at 221.09 nm and detected at 221.64 nm. We demonstrate the detection of silicon LIF down to laser welding powers of 600 W (210 kW cm-2) making this technique applicable even in low-power laser welding or additive manufacturing scenarios.

  15. 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.

  16. Plating on stainless steel alloys

    SciTech Connect

    Dini, J.W.; Johnson, H.R.

    1981-09-11

    Quantitative adhesion data are presented for a variety of electroplated stainless steel type alloys. Results show that excellent adhesion can be obtained by using a Wood's nickel strike or a sulfamate nickel strike prior to final plating. Specimens plated after Wood's nickel striking failed in the deposit rather than at the interface between the substrate and the coating. Flyer plate quantitative tests showed that use of anodic treatment in sulfuric acid prior to Wood's nickel striking even further improved adhesion. In contrast activation of stainless steels by immersion or cathodic treatment in hydrochloric acid resulted in very reduced bond strengths with failure always occurring at the interface between the coating and substrate.

  17. Sensitization and Intergranular Corrosion Behavior of High Nitrogen Type 304LN Stainless Steels for Reprocessing and Waste Management Applications

    NASA Astrophysics Data System (ADS)

    Parvathavarthini, N.; Kamachi Mudali, U.; Nenova, Lilyana; Andreev, Chavdar; Raj, Baldev

    2012-06-01

    High nitrogen 304LN stainless steels (SS) intended for chloride and nitric acid environments in spent nuclear fuel reprocessing and waste management applications were evaluated for their sensitization and intergranular corrosion (IGC) resistance. For this purpose, high nitrogen (0.132 pct, 0.193 pct and 0.406 pct) containing, impurity-controlled, vanadium-added 304LN SS alloys were developed. For comparison, 304L SS, which is currently used in reprocessing plants, was also studied. These stainless steels were subjected to heat treatment at 948 K (675 °C) for various durations ranging from 1 to 1000 hours and tested for susceptibility to IGC as per ASTM A262 Practice A and E tests. The degree of sensitization was estimated with the double loop electrochemical potentiokinetic reactivation technique. The increase in nitrogen content resulted in higher hardness and finer grain size. Based on the detailed microstructural and corrosion studies, it was determined that an addition of 0.132 pct and 0.193 pct nitrogen showed better IGC resistance and an additional increase in nitrogen resulted in deterioration resulting from chromium nitride precipitation, which was confirmed by electrochemical phase separation and X-ray diffraction studies. The onset of desensitization was faster for the alloy with 0.132 pct nitrogen as well as 0.406 pct nitrogen because of the lower nitrogen content in the former case and the finer grain size in the latter case. The higher hardness and superior IGC resistance of 0.132 pct and 0.193 pct nitrogen containing Type 304LN SS suggests the suitability of this alloy for nitric acid- and chloride-containing environments of reprocessing and waste management plants.

  18. Strain induced grain boundary migration effects on grain growth of an austenitic stainless steel during static and metadynamic recrystallization

    SciTech Connect

    Paggi, A.; Angella, G.; Donnini, R.

    2015-09-15

    Static and metadynamic recrystallization of an AISI 304L austenitic stainless steel was investigated at 1100 °C and 10{sup −} {sup 2} s{sup −} {sup 1} strain rate. The kinetics of recrystallization was determined through double hit compression tests. Two strain levels were selected for the first compression hit: ε{sub f} = 0.15 for static recrystallization (SRX) and 0.25 for metadynamic recrystallization (MDRX). Both the as-deformed and the recrystallized microstructures were investigated through optical microscopy and electron back-scattered diffraction (EBSD) technique. During deformation, strain induced grain boundary migration appeared to be significant, producing a square-like grain boundary structure aligned along the directions of the maximum shear stresses in compression. EBSD analysis revealed to be as a fundamental technique that the dislocation density was distributed heterogeneously in the deformed grains. Grain growth driven by surface energy reduction was also investigated, finding that it was too slow to explain the experimental data. Based on microstructural results, it was concluded that saturation of the nucleation sites occurred in the first stages of recrystallization, while grain growth driven by strain induced grain boundary migration (SIGBM) dominated the subsequent stages. - Highlights: • Recrystallization behavior of a stainless steel was investigated at 1100 °C. • EBSD revealed that the dislocation density distribution was heterogeneous during deformation. • Saturation of nucleation sites occurred in the first stages of recrystallization. • Strain induced grain boundary migration (SIGBM) effects were significant. • Grain growth driven by SIGBM dominated the subsequent stages.

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

    SciTech Connect

    Chung, H. M.; Ruther, W. E.; Strain, R. V.; Shack, W. J.; Karlsen, T. M.

    1999-10-26

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

  20. Long-term aging of type 308 stainless steel welds: Effects on properties and microstructure

    SciTech Connect

    Alexander, D.J.; Vitek, J.M.; David, S.A.

    1994-09-01

    Multipass gas tungsten arc welds with type 308 stainless steel filler metal in type 304L base plate have been aged at 400, 475, or 550{degrees}C for times up to 5,000 h. The changes in mechanical properties as a result of these agings have been followed with tensile, impact, and fracture toughness testing, using subsize tensile, half-size Charpy, and 0.45T compact specimens, respectively. The changes in the microstructure were evaluated with optical and transmission electron microscopy. Relatively little change was observed in the tensile properties for any of the aging treatments, but significant embrittlement was observed in the impact and fracture toughness testing. The transition temperatures increased rapidly for aging at 475 or 550{degrees}C, and more slowly for aging at 400{degrees}C. The upper-shelf energies and the fracture toughness showed similar responses, with only a small decrease for 400{degrees}C aging, but much greater and rapid decreases with aging at 475 or 550{degrees}C. Aging at 400 or 475{degrees}C resulted in the spinodal decomposition of the ferrite phase in the weld metal into iron-rich alpha and chromium-enriched alpha prime. In addition, at 475{degrees}C G-phase precipitates formed homogeneously in the ferrite and also at dislocations. At 550{degrees}C carbides formed and grew at the ferrite-austenite interfaces, and some ferrite transformed to sigma phase. These changes must all be considered in determining the effect of aging on the fracture properties.

  1. Nano/ultrafine grained austenitic stainless steel through the formation and reversion of deformation-induced martensite: Mechanisms, microstructures, mechanical properties, and TRIP effect

    SciTech Connect

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

    2015-05-15

    A comprehensive study was carried out on the strain-induced martensitic transformation, its reversion to austenite, the resultant grain refinement, and the enhancement of strength and strain-hardening ability through the transformation-induced plasticity (TRIP) effect in a commercial austenitic 304L stainless steel with emphasis on the mechanisms and the microstructural evolution. A straightforward magnetic measurement device, which is based on the measurement of the saturation magnetization, for evaluating the amount of strain-induced martensite after cold rolling and reversion annealing in metastable austenitic stainless steels was used, which its results were in good consistency with those of the X-ray diffraction (XRD) method. A new parameter called the effective reduction in thickness was introduced, which corresponds to the reasonable upper bound on the obtainable martensite fraction based on the saturation in the martensitic transformation. By means of thermodynamics calculations, the reversion mechanisms were estimated and subsequently validated by experimental results. The signs of thermal martensitic transformation at cooling stage after reversion at 850 °C were found, which was attributed to the rise in the martensite start temperature due to the carbide precipitation. After the reversion treatment, the average grain sizes were around 500 nm and the nanometric grains of the size of ~ 65 nm were also detected. The intense grain refinement led to the enhanced mechanical properties and observation of the change in the work-hardening capacity and TRIP effect behavior. A practical map as a guidance for grain refining and characterizing the stability against grain growth was proposed, which shows the limitation of the reversion mechanism for refinement of grain size. - Graphical abstract: Display Omitted - Highlights: • Nano/ultrafine grained austenitic stainless steel through martensite treatment • A parameter descriptive of a reasonable upper bound on

  2. TRITIUM AGING EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL BASE METAL AND WELDS

    SciTech Connect

    Morgan, M.

    2009-07-30

    -energy-rate forged are needed for designing and establishing longer tritium-reservoir lifetimes, ranking materials, and, potentially, for qualifying new forging vendors or processes. Measurements on the effects of tritium and decay helium on the fracture toughness properties of CF stainless steels having similar composition, grain size, and mechanical properties to previously studied HERF steels are needed and have not been conducted until now. The compatibility of stainless steel welds with tritium represents another concern for long-term reservoir performance. Weldments have not been well-characterized with respect to tritium embrittlement, although a recent study was completed on the effect of tritium and decay helium on the fracture toughness properties of Type 304L weldments. This study expands the characterization of weldments through measurements of tritium and decay helium effects on the fracture toughness properties of Type 21-6-9 stainless steel. The purpose of this study was to measure and compare the fracture toughness properties of Type 21-6-9 stainless steel for conventional forgings and weldments in the non-charged, hydrogen-charged and tritium-charged-and-aged conditions.

  3. 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.

  4. 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.

  5. 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...

  6. Fracture Mechanical Measurements with Commercial Stainless Steels at 4 K and with Cp-Titanium at 173 K

    NASA Astrophysics Data System (ADS)

    Nyilas, A.; Mitterbacher, H.

    2010-04-01

    Using the JETT (J-Evaluation on Tensile Test) technique, measurements have been performed with commercial stainless steels in forged and cast condition for the reason of an assessment for low temperature service down to 4 K. These steels frequently used for industrial applications are designated by German Werkstoff (WNr) 1.4308 and 1.4408 cast stainless steels and a forged material with the number 1.4307. The fracture toughness tests at 4 K with forged material 1.4307 comprised apart from the base metal also the weld zone and additionally the 5% and 8% pre-strained conditions of the base metal. Fracture toughness reduced slightly for cold worked condition gradually as well as for the weld joint. The Reliability of the JETT measurements has been also checked using the ASTM E 1820—99a standard. In addition, to these measurements, commercial pure ASTM grade 2 titanium (WNr 3.7035) has been also examined using the same JETT method for the reason of industrial application and the requirement of minimum fracture toughness of 100 MPa√m was fulfilled at 173 K. Furthermore, test results performed at 7 K of pure titanium plate material (ASTM grade 1) with respect to fracture mechanical JETT method are presented.

  7. Annealing induced interfacial layers in niobium-clad stainless steel developed as a bipolar plate material for polymer electrolyte membrane fuel cell stacks

    SciTech Connect

    Hong, Sung Tae; Weil, K. Scott; Choi, Jung-Pyung; Bae, In-Tae; Pan, Jwo

    2010-05-01

    Niobium (Nb)-clad 304L stainless steel (SS) manufactured by cold rolling is currently under consideration for use as a bipolar plate material in polymer electrolyte membrane fuel cell (PEMFC) stacks. To make the fabrication of bipolar plates using the Nb-clad SS feasible, annealing may be necessary for the Nb-clad SS to reduce the springback induced by cold rolling. However, the annealing can develop an interfacial layer between the Nb cladding and the SS core and the interfacial layer plays a key role in the failure of the Nb-clad SS as reported earlier [JPS our work]. In this investigation, the Nb-clad SS specimens in as-rolled condition were annealed at different combinations of temperature and time. Based on the results of scanning electron microscope (SEM) analysis, an annealing process map for the Nb-clad SS was obtained. The results of SEM analysis and Transmission Electron Microscope (TEM) analysis also suggest that different interfacial layers occurred based on the given annealing conditions.

  8. Improving the performance of stainless-steel DC high voltage photoelectron gun cathode electrodes via gas conditioning with helium or krypton

    SciTech Connect

    BastaniNejad, M.; Elmustafa, A. A.; Forman, E.; Clark, J.; Covert, S.; Grames, J.; Hansknecht, J.; Hernandez-Garcia, C.; Poelker, M.; Suleiman, R.

    2014-10-01

    Gas conditioning was shown to eliminate field emission from cathode electrodes used inside DC high voltage photoelectron guns, thus providing a reliable means to operate photoguns at higher voltages and field strengths. Measurements and simulation results indicate that gas conditioning eliminates field emission from cathode electrodes via two mechanisms: sputtering and implantation, with the benefits of implantation reversed by heating the electrode. We have studied five stainless steel electrodes (304L and 316LN) that were polished to approximately 20 nm surface roughness using diamond grit, and evaluated inside a high voltage apparatus to determine the onset of field emission as a function of voltage and field strength. The field emission characteristics of each electrode varied significantly upon the initial application of voltage but improved to nearly the same level after gas conditioning using either helium or krypton, exhibiting less than 10 pA field emission at -225 kV bias voltage with a 50 mm cathode/anode gap, corresponding to a field strength of ~13 MV/m. Finally, field emission could be reduced with either gas, but there were conditions related to gas choice, voltage and field strength that were more favorable than others.

  9. Solderability study of 63Sn-37Pb on zinc-plated and cadmium-plated stainless steel for the MC4636 lightning arrestor connector.

    SciTech Connect

    Lopez, Edwin Paul; Vianco, Paul Thomas; Rejent, Jerome Andrew; Martin, Joseph J.

    2004-06-01

    Cadmium plating on metal surfaces is commonly used for corrosion protection and to achieve good solderability on the 304L stainless steel shell of the MC4636 lightning arrestor connector (LAC) for the W76-1 system. This study examined the use of zinc as a potential substitute for the cadmium protective surface finish. Tests were performed with an R and RMA flux and test temperatures of 230 C, 245 C, and 260 C. Contact angle, {theta}{sub c}, served as the generalized solderability metric. The wetting rate and wetting time parameters were also collected. The solderability ({theta}{sub c}) of the Erie Plating Cd/Ni coatings was better than that of similar Amphenol coatings. Although the {theta}{sub c} data indicated that both Cd/Ni platings would provide adequate solderability, the wetting rate and wetting time data showed the Amphenol coatings to have better performance. The Zn/Ni coatings exhibited non-wetting under all flux and temperature conditions. Based on the results of these tests, it has been demonstrated that zinc plating is not a viable alternate to cadmium plating for the LAC connectors.

  10. Improving the performance of stainless-steel DC high voltage photoelectron gun cathode electrodes via gas conditioning with helium or krypton

    NASA Astrophysics Data System (ADS)

    BastaniNejad, M.; Elmustafa, A. A.; Forman, E.; Clark, J.; Covert, S.; Grames, J.; Hansknecht, J.; Hernandez-Garcia, C.; Poelker, M.; Suleiman, R.

    2014-10-01

    Gas conditioning was shown to eliminate field emission from cathode electrodes used inside DC high voltage photoelectron guns, thus providing a reliable means to operate photoguns at higher voltages and field strengths. Measurements and simulation results indicate that gas conditioning eliminates field emission from cathode electrodes via two mechanisms: sputtering and implantation, with the benefits of implantation reversed by heating the electrode. We have studied five stainless steel electrodes (304L and 316LN) that were polished to approximately 20 nm surface roughness using diamond grit, and evaluated inside a high voltage apparatus to determine the onset of field emission as a function of voltage and field strength. The field emission characteristics of each electrode varied significantly upon the initial application of voltage but improved to nearly the same level after gas conditioning using either helium or krypton, exhibiting less than 10 pA field emission at -225 kV bias voltage with a 50 mm cathode/anode gap, corresponding to a field strength of ~13 MV/m. Field emission could be reduced with either gas, but there were conditions related to gas choice, voltage and field strength that were more favorable than others.

  11. 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.

  12. 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.

  13. 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.

  14. The comparison of frictional resistance in titanium, self-ligating stainless steel, and stainless steel brackets using stainless steel and TMA archwires: An in vitro study

    PubMed Central

    Khalid, Syed Altaf; Kumar, Vadivel; Jayaram, Prithviraj

    2012-01-01

    Aim: The aim of the study was to compare the frictional resistance of titanium, self-ligating stainless steel, and conventional stainless steel brackets, using stainless steel and titanium molybdenum alloy (TMA) archwires. Materials and Methods: We compared the frictional resistance in 0.018 slot and 0.022 slot of the three brackets – titanium, self-ligating stainless steel, and conventional stainless steel – using stainless steel archwires and TMA archwires. An in vitro study of simulated canine retraction was undertaken to evaluate the difference in frictional resistance between titanium, self-ligating stainless steel, and stainless steel brackets, using stainless steel and TMA archwires. Results and Conclusion: We compared the frictional resistance of titanium, self-ligating stainless steel, and conventional stainless steel brackets, using stainless steel and TMA archwires, with the help of Instron Universal Testing Machine. One-way analysis of variance (ANOVA), Student's “t” test, and post hoc multiple range test at level of <0.05 showed statistically significant difference in the mean values of all groups. Results demonstrated that the titanium, self-ligating stainless steel, and stainless steel brackets of 0.018-inch and 0.022-inch slot had no significant variations in frictional résistance. The self-ligating bracket with TMA archwires showed relatively less frictional resistance compared with the other groups. The titanium bracket with TMA archwires showed relatively less frictional resistance compared with the stainless steel brackets. PMID:23066253

  15. The comparison of frictional resistance in titanium, self-ligating stainless steel, and stainless steel brackets using stainless steel and TMA archwires: An in vitro study.

    PubMed

    Khalid, Syed Altaf; Kumar, Vadivel; Jayaram, Prithviraj

    2012-08-01

    The aim of the study was to compare the frictional resistance of titanium, self-ligating stainless steel, and conventional stainless steel brackets, using stainless steel and titanium molybdenum alloy (TMA) archwires. We compared the frictional resistance in 0.018 slot and 0.022 slot of the three brackets - titanium, self-ligating stainless steel, and conventional stainless steel - using stainless steel archwires and TMA archwires. An in vitro study of simulated canine retraction was undertaken to evaluate the difference in frictional resistance between titanium, self-ligating stainless steel, and stainless steel brackets, using stainless steel and TMA archwires. We compared the frictional resistance of titanium, self-ligating stainless steel, and conventional stainless steel brackets, using stainless steel and TMA archwires, with the help of Instron Universal Testing Machine. One-way analysis of variance (ANOVA), Student's "t" test, and post hoc multiple range test at level of <0.05 showed statistically significant difference in the mean values of all groups. Results demonstrated that the titanium, self-ligating stainless steel, and stainless steel brackets of 0.018-inch and 0.022-inch slot had no significant variations in frictional résistance. The self-ligating bracket with TMA archwires showed relatively less frictional resistance compared with the other groups. The titanium bracket with TMA archwires showed relatively less frictional resistance compared with the stainless steel brackets.

  16. 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.

  17. A Hierarchical Upscaling Method for Predicting Strength of Materials under Thermal, Radiation and Mechanical loading - Irradiation Strengthening Mechanisms in Stainless Steels

    SciTech Connect

    Li, Dongsheng; Zbib, Hussein M.; Garmestani, Hamid; Sun, Xin; Khaleel, Mohammad A.

    2011-07-01

    Stainless steels based on Fe-Cr-Ni alloys are the most popular structural materials used in reactors. High energy particle irradiation of in this kind of polycrystalline structural materials usually produces irradiation hardening and embrittlement. The development of predictive capability for the influence of irradiation on mechanical behavior is very important in materials design for next-generation reactors. Irradiation hardening is related to structural information crossing different length scale, such as composition, dislocation, crystal orientation distribution and so on. To predict the effective hardening, the influence factors along different length scales should be considered. A multiscale approach was implemented in this work to predict irradiation hardening of iron based structural materials. Three length scales are involved in this multiscale model: nanometer, micrometer and millimeter. In the microscale, molecular dynamics (MD) was utilized to predict on the edge dislocation mobility in body centered cubic (bcc) Fe and its Ni and Cr alloys. On the mesoscale, dislocation dynamics (DD) models were used to predict the critical resolved shear stress from the evolution of local dislocation and defects. In the macroscale, a viscoplastic self-consistent (VPSC) model was applied to predict the irradiation hardening in samples with changes in texture. The effects of defect density and texture were investigated. Simulated evolution of yield strength with irradiation agrees well with the experimental data of irradiation strengthening of stainless steel 304L, 316L and T91. This multiscale model we developed in this project can provide a guidance tool in performance evaluation of structural materials for next-generation nuclear reactors. Combining with other tools developed in the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program, the models developed will have more impact in improving the reliability of current reactors and affordability of new

  18. Tensile Properties, Ferrite Contents, and Specimen Heating of Stainless Steels in Cryogenic Gas Tests

    SciTech Connect

    Ogata, T.; Yuri, T.; Ono, Y.

    2006-03-31

    We performed tensile tests at cryogenic temperatures below 77 K and in helium gas environment for SUS 304L and SUS 316L in order to obtain basic data of mechanical properties of the materials for liquid hydrogen tank service. We evaluate tensile curves, tensile properties, ferrite contents, mode of deformation and/or fracture, and specimen heating during the testing at 4 to 77 K. For both SUS 304L and 316L, tensile strength shows a small peak around 10 K, and specimen heating decreases above 30 K. The volume fraction of {alpha}-phase increases continuously up to 70 % with plastic strain, at approximately 15 % plastic strain for 304L and up to 35 % for 316L. There was almost no clear influence of testing temperature on strain-induced martensitic transformation at the cryogenic temperatures.

  19. 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).

  20. 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.

  1. Contribution à la modélisation du soudage TIG des tôles minces d'acier austénitique 304L par un modèle source bi-elliptique, avec confrontation expérimentale

    NASA Astrophysics Data System (ADS)

    Aissani, M.; Maza, H.; Belkessa, B.; Maamache, B.

    2005-05-01

    Ce travail contribue dans la modélisation du phénomène du soudage de l'acier inoxydable Austénitique 304L, afin d'étudier le comportement thermique d'un joint de soudure, obtenu par le procédé de soudage à l'arc électrique TIG (Tungsten-Inert-Gas). Le modèle simulant la source d'énergie de soudage, utilise une distribution surfacique Gaussienne du flux de chaleur provenant de l'arc électrique. La forme de cette source est supposée circulaire pour un premier cas et de forme bi-elliptique pour un second cas, tout en procédant à l'évaluation des champs et cycles thermiques à chaque instant, pour déterminer l'étendu des zones à risque, et l'effet de la vitesse de soudage sur ces dernières. Permettant ainsi de remonter par la suite, aux problèmes de contraintes résiduelles et déformations générées dans l'assemblage soudé. L'équation de chaleur régissant le problème est discrétisée par la méthode des volumes finis. Les calculs sont effectués en considérant que les propriétés physiques et thermiques ainsi que les conditions aux limites de convection et rayonnement, sont dépendante de la température. Pour évaluer la précision du modèle, une comparaison avec des mesures expérimentales de température d'un essai de soudage a été effectuée, les résultats indiquent un bon accord.

  2. The Effect of Mold Flux on Reheat Scale -- Austenitic Stainless Steel Slabs

    NASA Astrophysics Data System (ADS)

    Cheung, Kelvin H.

    In the present study, the characteristics of the subscale were investigated with respect to alloy composition, oxidizing environment, and surface treatment. Samples were tested isothermally under simulated reheating conditions with regards to time, temperature and oxidizing gas composition. Findings suggest that water vapor is a key variable in dictating the scale growth mechanisms during reheating of type 304 stainless steel. The volatilization of CrO 2(OH)2 in the presence of water vapor is one factor which can prevent stainless steel from forming a continuous external eskolaite layer; mold flux can influence this behavior. FactSage calculations were done to compare the maximum equilibrium solubilities of major oxide species in mold flux and the maximum equilibrium partial pressure of volatilized chromium oxide species in atmospheres with and without water vapor content. FactSage results also helped to model expected local equilibrium oxide formation as a function extent of oxidation. From that work, a mechanism was developed to explain deep subscale formation. A mechanism is proposed to explain how mold flux avoids deep subscale formation due to its low solubility of chromium oxide, promoting the formation of a continuous eskolaite oxide layer by preventing chromium loss by volatilization. A series of Fe-xCr binary alloys with x ranging from 14 to 24 wt% were used to investigate the isolated effects of chromium content on oxidation behavior and scale morphology as a function of surface treatment and oxidizing environment. Type 304L stainless steel was also tested. These tests were specifically aimed at investigating the effect of chromium volatilization on continuous external eskolaite formation during high temperature oxidation and to elucidate the mechanism involved in how the presence of mold flux influences this behavior. The samples were oxidized either in a wet atmosphere (laboratory air and 18%H 2O content simulated reheating atmosphere) or dry N2-O 2 gas

  3. 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.

  4. 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.

  5. 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.

  6. Development of a carburizing stainless steel alloy

    SciTech Connect

    Wert, D.E. )

    1994-06-01

    A new carburizing stainless steel alloy that resists corrosion, heat, and fatigue has been developed for bearing and gear applications. Pyrowear 675 Stainless alloy is vacuum induction melted and vacuum arc remelted (VIM/VAR) for aircraft-quality cleanliness. Test results show that it has corrosion resistance similar to that of AISI Type 440-C stainless, and its rolling fatigue resistance is superior to that of AISI M50 (UNS K88165). In contrast to alloy gear steels and Type 440C, Pyrowear 675 maintains case hardness of HRC 60 at operating temperatures up to 200 C (400 F). Impact and fracture toughness are superior to that of other stainless bearing steels, which typically are relatively brittle and can break under severe service. Toughness is also comparable or superior to conventional noncorrosion-resistant carburizing bearing steels, such as SAE Types 8620 and 9310.

  7. 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

  8. 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.

  9. 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.

  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. Casting Stainless-Steel Models Around Pressure Tubes

    NASA Technical Reports Server (NTRS)

    Vasquez, Peter; Micol, John R.

    1992-01-01

    Survivability of thin-wall stainless-steel tubing increased to nearly 100 percent. Improves state of art in pressure-model castings and reduces cost associated with machining complete model from stainless-steel blank.

  12. Casting Stainless-Steel Models Around Pressure Tubes

    NASA Technical Reports Server (NTRS)

    Vasquez, Peter; Micol, John R.

    1992-01-01

    Survivability of thin-wall stainless-steel tubing increased to nearly 100 percent. Improves state of art in pressure-model castings and reduces cost associated with machining complete model from stainless-steel blank.

  13. 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.

  14. Irradiation-assisted stress corrosion cracking behavior of austenitic stainless steels applicable to LWR core internals.

    SciTech Connect

    Chung, H. M.; Shack, W. J.; Energy Technology

    2006-01-31

    This report summarizes work performed at Argonne National Laboratory on irradiation-assisted stress corrosion cracking (IASCC) of austenitic stainless steels that were irradiated in the Halden reactor in simulation of irradiation-induced degradation of boiling water reactor (BWR) core internal components. Slow-strain-rate tensile tests in BWR-like oxidizing water were conducted on 27 austenitic stainless steel alloys that were irradiated at 288 C in helium to 0.4, 1.3, and 3.0 dpa. Fractographic analysis was conducted to determine the fracture surface morphology. Microchemical analysis by Auger electron spectroscopy was performed on BWR neutron absorber tubes to characterize grain-boundary segregation of important elements under BWR conditions. At 0.4 and 1.4 dpa, transgranular fracture was mixed with intergranular fracture. At 3 dpa, transgranular cracking was negligible, and fracture surface was either dominantly intergranular, as in field-cracked core internals, or dominantly ductile or mixed. This behavior indicates that percent intergranular stress corrosion cracking determined at {approx}3 dpa is a good measure of IASCC susceptibility. At {approx}1.4 dpa, a beneficial effect of a high concentration of Si (0.8-1.5 wt.%) was observed. At {approx}3 dpa, however, such effect was obscured by a deleterious effect of S. Excellent resistance to IASCC was observed up to {approx}3 dpa for eight heats of Types 304, 316, and 348 steel that contain very low concentrations of S. Susceptibility of Types 304 and 316 steels that contain >0.003 wt.% S increased drastically. This indicates that a sulfur related critical phenomenon plays an important role in IASCC. A sulfur content of <0.002 wt.% is the primary material factor necessary to ensure good resistance to IASCC. However, for Types 304L and 316L steel and their high-purity counterparts, a sulfur content of <0.002 wt.% alone is not a sufficient condition to ensure good resistance to IASCC. This is in distinct contrast to

  15. Effect of prior deformation on sensitization development in stainless steel during continuous cooling

    SciTech Connect

    Simmons, J.W.; Atteridge, D.G.; Bruemmer, S.M. . Dept. of Materials Science and Engineering)

    1991-09-01

    Continuous cooling sensitization (CCS) occurs in austenitic stainless steel (SS) weldment HAZs where the material is subjected to weld-induced plastic deformation, and non-linear heating and cooling cycles. The primary purpose of this investigation was to quantitatively determine the effects of prior deformation on CCS. In addition, these results were used to develop a CCS data base for comparison to a recently published sensitization prediction model (SSDOS). Continuous cooling thermal cycling of specimens from high-carbon Type 316 SSs was performed in a computer-controlled Gleeble thermal simulator. The degree of sensitization (DOS) of thermally treated specimens was quantitatively measured using the electrochemical potentiokinetic reactivation (EPR) test. Prior deformation significantly enhanced the rate of CCS development in the Type 316 SS material. The DOS increased with increasing amounts of prior strain and decreasing cooling rates. Sensitization response was also sensitive to peak cycle temperatures. Continuous cooling sensitization development occurred primarily in the critical temperature range between about 900 and 750{degree}C. Peak cycle temperatures of 1000 and 1050{degree}C retarded sensitization development during subsequent continuous cooling. Strain recovery at elevated temperatures played an important role in reducing the effectiveness of prior deformation in accelerating sensitization kinetics. Due to the effects of recovery, in certain cases, prior strain values of 20% were only as effective as 10% in increasing the rate of sensitization development. Limited transgranular carbide precipitation was observed in 20% prior strain samples depending on specific thermal cycle parameters but was not a significant factor in the present work. The SSDOS model consistently overpredicted the CCS development in both heats of 316 SS studied, regardless of material condition (i.e. mill-annealed, solution-annealed, and pre-strained materials).

  16. 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%.

  17. 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.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. Bondable Stainless Surface Coats Protect Against Rust

    NASA Technical Reports Server (NTRS)

    Davis, G. D.; Shaffer, D. K.; Clearfield, H. M.; Nagle, D.; Groff, G.

    1995-01-01

    Report describes tests conducted to assess use of bondable stainless surface (BOSS) coating materials to protect steel cases of solid-fuel rocket motors against corrosion and to provide surface microstructure and chemistry suitable for bonding to insulating material. Eliminates need to cover cases with grease to prevent corrosion and degreasing immediately prior to use.

  8. 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.

  9. 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.

  10. 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.

  11. Materials data handbooks on stainless steels

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    Two handbooks which summarize latest available data have been published. Two types of stainless steels, alloy A-286 and Type 301, are described. Each handbook is divided into twelve chapters. Scope of information presented includes physical- and mechanical-property data at cryogenic, ambient, and elevated temperatures.

  12. Bondable Stainless Surface Coats Protect Against Rust

    NASA Technical Reports Server (NTRS)

    Davis, G. D.; Shaffer, D. K.; Clearfield, H. M.; Nagle, D.; Groff, G.

    1995-01-01

    Report describes tests conducted to assess use of bondable stainless surface (BOSS) coating materials to protect steel cases of solid-fuel rocket motors against corrosion and to provide surface microstructure and chemistry suitable for bonding to insulating material. Eliminates need to cover cases with grease to prevent corrosion and degreasing immediately prior to use.

  13. Proof Testing Of Stainless-Steel Bolts

    NASA Technical Reports Server (NTRS)

    Hsieh, Cheng H.; Hendrickson, James A.; Bamford, Robert M.

    1992-01-01

    Report describes study of development of method for nondestructive proof testing of bolts made of A286 stainless steel. Based on concept that the higher load bolt survives, the smaller the largest flaw and, therefore, the longer its fatigue life after test. Calculations and experiments increase confidence in nondestructive proof tests.

  14. 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

  15. 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).

  16. Phase Transformation in Cast Superaustenitic Stainless Steels

    SciTech Connect

    Lee Phillips, Nathaniel Steven

    2006-01-01

    Superaustenitic stainless steels constitute a group of Fe-based alloys that are compositionally balanced to have a purely austenitic matrix and exhibit favorable pitting and crevice corrosion resistant properties and mechanical strength. However, intermetallic precipitates such as sigma and Laves can form during casting or exposure to high-temperature processing, which degrade the corrosion and mechanical properties of the material. The goal of this study was to accurately characterize the solid-solid phase transformations seen in cast superaustenitic stainless steels. Heat treatments were performed to understand the time and temperature ranges for intermetallic phase formations in alloys CN3MN and CK3MCuN. Microstructures were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy and wavelength dispersive spectroscopy (EDS, WDS). The equilibrium microstructures, composed primarily of sigma and Laves within purely austenitic matrices, showed slow transformation kinetics. Factors that determine the extent of transformation, including diffusion, nucleation, and growth, are discussed.

  17. 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.

  18. Fatigue crack growth in metastable austenitic stainless steels

    SciTech Connect

    Mei, Z.; Chang, G.; Morris, J.W. Jr.

    1988-06-01

    The research reported here is an investigation of the influence of the mechanically induced martensitic transformation on the fatigue crack growth rate in 304-type steels. The alloys 304L and 304LN were used to test the influence of composition, the testing temperatures 298 K and 77 K were used to study the influence of test temperature, and various load ratios (R) were used to determine the influence of the load ratio. It was found that decreasing the mechanical stability of the austenite by changing composition or lowering temperature decreases the fatigue crack growth rate. The R-ratio effect is more subtle. The fatigue crack growth rate increases with increasing R-ratio, even though this change increases the martensite transformation. Transformation-induced crack closure can explain the results in the threshold regime, but cannot explain the R-ratio effect at higher cyclic stress intensities. 26 refs., 6 figs.

  19. 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.

  20. 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.

  1. 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.

  2. Softened-Stainless-Steel O-Rings

    NASA Technical Reports Server (NTRS)

    Marquis, G. A.; Waters, William I.

    1993-01-01

    In fabrication of O-ring of new type, tube of 304 stainless steel bent around mandril into circle and welded closed into ring. Ring annealed in furnace to make it soft and highly ductile. In this condition, used as crushable, deformable O-ring seal. O-ring replacements used in variety of atmospheres and temperatures, relatively inexpensive, fabricated with minimum amount of work, amenable to one-of-a-kind production, reusable, and environmentally benign.

  3. Colorimetric values of esthetic stainless steel crowns.

    PubMed

    Hosoya, Yumiko; Omachi, Koichi; Staninec, Michal

    2002-01-01

    The colorimetric values of two different kinds of esthetic stainless steel crowns were measured and compared with the colorimetric values of primary anterior teeth in Japanese children. The colorimetric values of resin composite-faced stainless steel crowns (Kinder Krown) and epoxy-coated stainless steel crowns (White Steel Crown) were measured with a color difference meter. The Commission Internationale de Eclairage L*, a*, b*, and delta E*ab values and Munsell value, chroma, and hue were calculated. The data were compared with previously reported colorimetric values of Japanese primary anterior teeth measured with the same color difference meter used in this study. Compared to Japanese primary anterior teeth, Kinder Krown Pedo I and Pedo II showed much higher L* values and lower hue; on the other hand, White Steel Crown showed much higher L*, a*, b* values, much higher value and chroma, and much lower hue. Color analysis revealed that the colors of the White Steel Crown and Kinder Krown Pedo I were substantially different from the color of Japanese primary anterior teeth. The color difference between Pedo II crowns and Japanese primary anterior teeth was relatively high, but the color of Pedo II might be acceptable for clinical use.

  4. 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.

  5. 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.

  6. Nickel-free duplex stainless steels

    SciTech Connect

    Wang, J.; Uggowitzer, P.J.; Magdowski, R.; Speidel, M.O.

    1998-12-04

    It is well known that nitrogen-alloying in steel produces a variety of exceptional properties such as high strength, high ductility and, eventually, resistance to stress corrosion cracking. High-nitrogen steels (HNS), therefore, have recently been developed to enhance the strength and corrosion resistance of stainless steels. However, due to a low solubility of nitrogen in a liquid steel under atmospheric pressure, the production of such high-nitrogen alloys needs high-pressure facilities that cause an extra cost. A possible route of developing high-nitrogen alloys under atmospheric pressure is to choose a duplex microstructure, where the amount of austenite and ferrite phase is nearly equal. A much lower nitrogen content is needed to maintain a 50% austenite phase compared with the necessary addition of nitrogen to reach a 100% austenitic microstructure. In addition, duplex stainless steels (DSS) with 40--60% ferrite can significantly improve the SCC-resistance. The objective of this work was to develop a new group of nickel-free, high strength and corrosion resistant DSS. Nickel was completely replaced by nitrogen in order to enhance SCC resistance and reduce the alloying element cost. The microstructure, mechanical properties, corrosion resistance and cost analysis of new alloys are investigated in comparison with some commercial stainless steels.

  7. 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.

  8. 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.

  9. 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.

  10. Corrosion Behavior of Stainless Steels in Neutral and Acidified Sodium Chloride Solutions by Electrochemical Impedance Spectroscopy

    NASA Technical Reports Server (NTRS)

    Calle, L. M.; Kolady, M. R.; Vinje, R. D.

    2004-01-01

    The objective of this work was to evaluate the corrosion performance of three alloys by Electrochemical Impedance Spectroscopy (EIS) and to compare the results with those obtained during a two-year atmospheric exposure study.' Three alloys: AL6XN (UNS N08367), 254SM0 (UNS S32154), and 304L (UNS S30403) were included in the study. 304L was included as a control. The alloys were tested in three electrolyte solutions which consisted of neutral 3.55% NaC1, 3.55% NaC1 in 0.lN HC1, and 3.55% NaC1 in 1.ON HC1. These conditions were expected to be less severe, similar, and more severe respectively than the conditions at NASA's Kennedy Space Center launch pads.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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...

  16. 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.

  17. 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 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture....

  18. 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 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture....

  19. 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 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture....

  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 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture....

  1. 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 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture....

  2. 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...

  3. 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).

  4. VIEW OF PRECISION EQUIPMENT USED IN STAINLESS COMPONENT MANUFACTURING. THE ...

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

    VIEW OF PRECISION EQUIPMENT USED IN STAINLESS COMPONENT MANUFACTURING. THE FACILITY WAS DESCRIBED AS THE MOST MODERN NON-NUCLEAR MANUFACTURING BUILDING IN THE U.S. DEPARTMENT OF ENERGY COMPLEX, WITH MANY PRECISION INSTRUMENTS. (9/21/83) - Rocky Flats Plant, Stainless Steel & Non-Nuclear Components Manufacturing, Southeast corner of intersection of Cottonwood & Third Avenues, Golden, Jefferson County, CO

  5. Descaling: Removal of Heat-Treat Scale from Stainless Steels,

    DTIC Science & Technology

    Several panels of 17-7 PH stainless steels were cleaned by various procedures and heat-treated to the TH 1050 condition. The cleaning procedre which... 1050 and examined for harmful effects. The preferred procedure for producing clean scale-free heat-treated stainless steel parts was to treat the parts

  6. Recommended Stainless Steel Welding Procedures for Corps of Engineers Construction.

    DTIC Science & Technology

    Two stainless steel welding methods are investigated for potential use in Corps of Engineers construction. The methods-gas tungsten-arc welding ( GTAW ...electron microscopy. Results show that GTAW and SMAW provide sound welds in the two stainless steels tested. Moreover, using low-carbon electrodes and

  7. 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.

  8. 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

  9. New Method For Joining Stainless Steel to Titanium

    NASA Technical Reports Server (NTRS)

    Emanuel, W. H.

    1982-01-01

    In new process, edge of stainless-steel sheet is perforated, and joined to titanium by resistance seam welding. Titanium flows into perforations, forming a strong interlocking joint. Process creates a quasi-metallurgical bond between the thin sheets of stainless steel and titanium.

  10. Withdrawal Strength and Bending Yield Strength of Stainless Steel Nails

    Treesearch

    Douglas R. Rammer; Samuel L. Zelinka

    2015-01-01

    It has been well established that stainless steel nails have superior corrosion performance compared to carbon steel or galvanized nails in treated wood; however, their mechanical fastening behavior is unknown. In this paper, the performance of stainless steel nails is examined with respect to two important properties used in wood connection design: withdrawal strength...

  11. 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.

  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. 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.

  14. 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.

  15. 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.

  16. 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

  17. Characterization of friction stir welded joint of low nickel austenitic stainless steel and modified ferritic stainless steel

    NASA Astrophysics Data System (ADS)

    Mondal, Mounarik; Das, Hrishikesh; Ahn, Eun Yeong; Hong, Sung Tae; Kim, Moon-Jo; Han, Heung Nam; Pal, Tapan Kumar

    2017-09-01

    Friction stir welding (FSW) of dissimilar stainless steels, low nickel austenitic stainless steel and 409M ferritic stainless steel, is experimentally investigated. Process responses during FSW and the microstructures of the resultant dissimilar joints are evaluated. Material flow in the stir zone is investigated in detail by elemental mapping. Elemental mapping of the dissimilar joints clearly indicates that the material flow pattern during FSW depends on the process parameter combination. Dynamic recrystallization and recovery are also observed in the dissimilar joints. Among the two different stainless steels selected in the present study, the ferritic stainless steels shows more severe dynamic recrystallization, resulting in a very fine microstructure, probably due to the higher stacking fault energy.

  18. 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.

  19. 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...

  20. 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 of...

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

    PubMed

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

    2016-03-04

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

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

    PubMed Central

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

    2016-01-01

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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Stress corrosion cracking of stainless steels

    NASA Astrophysics Data System (ADS)

    Hehemann, R. F.

    1985-11-01

    The similarities and differences in the stress corrosion cracking response of ferritic and austenitic stainless steels in chloride solutions will be examined. Both classes of materials exhibit a cracking potential: similar transient response (to loading) of the potential in open circuit tests or the current in potentiostatic tests and similar enrichment of chromium and depletion of iron in the film associated with localized corrosion processes. The ferritic steels are more resistant to localized corrosion than are the austenitic steels, which is responsible for the difference in the influence of prior thermal and mechanical history on cracking susceptibility of the two types of steel. Similarities in the fractography of stress corrosion cracks and those produced by brittle delayed failure during cathodic charging of the ferritic steels indicate that hydrogen embrittlement is involved in the failure process.

  10. Automatic welding of stainless steel tubing

    NASA Technical Reports Server (NTRS)

    Clautice, W. E.

    1978-01-01

    The use of automatic welding for making girth welds in stainless steel tubing was investigated as well as the reduction in fabrication costs resulting from the elimination of radiographic inspection. Test methodology, materials, and techniques are discussed, and data sheets for individual tests are included. Process variables studied include welding amperes, revolutions per minute, and shielding gas flow. Strip chart recordings, as a definitive method of insuring weld quality, are studied. Test results, determined by both radiographic and visual inspection, are presented and indicate that once optimum welding procedures for specific sizes of tubing are established, and the welding machine operations are certified, then the automatic tube welding process produces good quality welds repeatedly, with a high degree of reliability. Revised specifications for welding tubing using the automatic process and weld visual inspection requirements at the Kennedy Space Center are enumerated.

  11. Stainless steel-zirconium alloy waste forms

    SciTech Connect

    McDeavitt, S.M.; Abraham, D.P.; Keiser, D.D. Jr.; Park, J.Y.

    1996-07-01

    An electrometallurgical treatment process has been developed by Argonne National Laboratory to convert various types of spent nuclear fuels into stable storage forms and waste forms for repository disposal. The first application of this process will be to treat spent fuel alloys from the Experimental Breeder Reactor-II. Three distinct product streams emanate from the electrorefining process: (1) refined uranium; (2) fission products and actinides extracted from the electrolyte salt that are processed into a mineral waste form; and (3) metallic wastes left behind at the completion of the electrorefining step. The third product stream (i.e., the metal waste stream) is the subject of this paper. The metal waste stream contains components of the chopped spent fuel that are unaffected by the electrorefining process because of their electrochemically ``noble`` nature; this includes the cladding hulls, noble metal fission products (NMFP), and, in specific cases, zirconium from metal fuel alloys. The selected method for the consolidation and stabilization of the metal waste stream is melting and casting into a uniform, corrosion-resistant alloy. The waste form casting process will be carried out in a controlled-atmosphere furnace at high temperatures with a molten salt flux. Spent fuels with both stainless steel and Zircaloy cladding are being evaluated for treatment; thus, stainless steel-rich and Zircaloy-rich waste forms are being developed. Although the primary disposition option for the actinides is the mineral waste form, the concept of incorporating the TRU-bearing product into the metal waste form has enough potential to warrant investigation.

  12. 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.

  13. 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.

  14. [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.

  15. A preliminary ferritic-martensitic stainless steel constitution diagram

    SciTech Connect

    Balmforth, M.C.; Lippold, J.C.

    1998-01-01

    This paper describes preliminary research to develop a constitution diagram that will more accurately predict the microstructure of ferritic and martensitic stainless steel weld deposits. A button melting technique was used to produce a wide range of compositions using mixtures of conventional ferritic and martensitic stainless steels, including types 403, 409, 410, 430, 439 and 444. These samples were prepared metallographically, and the vol-% ferrite and martensite was determined quantitatively. In addition, the hardness and ferrite number (FN) were measured. Using this data, a preliminary constitution diagram is proposed that provides a more accurate method for predicting the microstructures of arc welds in ferritic and martensitic 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. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Systems design of high performance stainless steels II. Prototype characterization

    NASA Astrophysics Data System (ADS)

    Campbell, C. E.; Olson, G. B.

    2000-10-01

    Within the framework of a systems approach, the design of a high performance stainless steel integrated processing/structure/property/performance relations with mechanistic computational models. Using multicomponent thermodynamic and diffusion software platforms, the models were integrated to design a carburizable, secondary-hardening, martensitic stainless steel for advanced gear and bearing applications. Prototype evaluation confirmed the predicted martensitic transformation temperature and the desired carburizing and tempering responses, achieving a case hardness of R c 64 in the secondary-hardened condition without case primary carbides. Comparison with a commercial carburizing stainless steel demonstrated the advantage of avoiding primary carbides to resist quench cracking associated with a martensitic start temperature gradient reversal. Based on anodic polarization measurements and salt-spray testing, the prototype composition exhibited superior corrosion resistance in comparison to the 440C stainless bearing steel, which has a significantly higher alloy Cr concentration.

  5. 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.

  6. Stress-Corrosion Cracking in Martensitic PH Stainless Steels

    NASA Technical Reports Server (NTRS)

    Humphries, T.; Nelson, E.

    1984-01-01

    Precipitation-hardening alloys evaluated in marine environment tests. Report describes marine-environment stress-corrosion cracking (SCC) tests of three martensitic precipitation hardening (PH) stainless-steel alloys.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Multilayer Mg-Stainless Steel Sheets, Microstructure, and Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Inoue, Junya; Sadeghi, Alireza; Kyokuta, Nobuhiko; Ohmori, Toshinori; Koseki, Toshihiko

    2017-05-01

    Different multilayer Mg AZ31 and SS304L steel sheet combinations were prepared with different volume fractions of Mg. Isolated stress-strain curves of the Mg layers showed significant improvements in the strength and elongation of multilayer samples. Results indicated that in the most extreme situation with the lowest Mg volume fraction ( V f = 0.39), the ultimate strength was increased by 25 pct to 370 MPa and the elongation was improved by 70 pct to 0.34. Investigation of the fracture surface showed that failure occurs by the coalescence of cracks close to the interface region. The improved strength of the multilayer samples was due to the combined effect of surface crack prevention by the steel layer and the higher work-hardening rate caused by the possible increased activity of non-basal systems. It is suggested that the stronger work-hardening behavior and the enhanced activity of non-basal systems in the multilayer samples were due to the formation of new stress components in the transverse direction. The larger the volume fraction of steel in the multilayer, the longer the distance remaining unstrained before the UTS.

  13. Multilayer Mg: Stainless Steel Sheets, Microstructure, and Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Inoue, Junya; Sadeghi, Alireza; Kyokuta, Nobuhiko; Ohmori, Toshinori; Koseki, Toshihiko

    2017-02-01

    Different multilayer Mg AZ31 and SS304L steel sheet combinations were prepared with different volume fractions of Mg. Isolated stress-strain curves of the Mg layers showed significant improvements in the strength and elongation of multilayer samples. Results indicated that in the most extreme situation with the lowest Mg volume fraction (V f = 0.39), the ultimate strength was increased by 25 pct to 370 MPa and the elongation was improved by 70 pct to 0.34. Investigation of the fracture surface showed that failure occurs by the coalescence of cracks close to the interface region. The improved strength of the multilayer samples was due to the combined effect of surface crack prevention by the steel layer and the higher work-hardening rate caused by the possible increased activity of non-basal systems. It is suggested that the stronger work-hardening behavior and the enhanced activity of non-basal systems in the multilayer samples were due to the formation of new stress components in the transverse direction. The larger the volume fraction of steel in the multilayer, the longer the distance remaining unstrained before the UTS.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. Comparison of titanium and Robinson stainless steel stapes piston prostheses.

    PubMed

    Lippy, William H; Burkey, John M; Schuring, Arnold G; Berenholz, Leonard P

    2005-09-01

    Although stainless steel stapes prostheses have generally been considered magnetic resonance imaging safe, there is concern that this may change with the development of more powerful imaging systems. The objective of the study was to determine whether a titanium piston stapes prosthesis would be audiometrically and surgically equivalent to a Robinson stainless steel piston for stapedectomy. Retrospective chart review. Private otology practice. In all, 50 patients underwent stapedectomy with a Gyrus titanium piston prosthesis. These patients were matched on the basis of age and preoperative bone-conduction scores with patients who underwent stapedectomy with a Robinson stainless steel piston prosthesis. Audiometric results are analyzed, and surgical complications noted. There was no significant difference between groups in hearing improvement or postoperative air-bone gap. The mean four-frequency hearing improvement was 27.7 dB for the stainless steel group and 27.8 dB for the titanium group. The mean postoperative air-bone gap was 2.65 dB for the stainless steel group and 2.60 for the titanium group. Neither group had a surgical complication. The titanium stapes prosthesis is a good alternative to a stainless steel prosthesis.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. AEM and AES of radiation-induced segregation in proton-irradiated stainless steels

    SciTech Connect

    Kenik, E.A.; Carter, R.D.; Damcott, D.L.; Atzmon, M.; Was, G.S.

    1994-06-01

    In order to avoid complications from long-term induced radioactivity of neutron-irradiated specimens, 4 type 304L alloys were irradiated to 1 dpa with 3.4 MeV protons at 400 C. Analytical electron microscopy and Auger electron spectrometry were used to measure composition at and near grain boundaries in controlled purity alloys. As a result of the narrow RIS profiles (<20 nm width) at grain boundaries induced in these materials by low temperature irradiation and the finite size of the excited volume for x-ray microanalysis, the measured profiles are convolutions of these two factors.

  4. 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.

  5. 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)

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Characterization of stainless steel 304 tubing

    SciTech Connect

    Sunwoo, A.J.; Brooks, M.A.; Kervin, J.E.

    1995-10-16

    Earlier studies have shown that stainless steel 304 (SS304) containing martensite is susceptible to hydrogen embrittlement. This generated concern regarding the structural integrity of SS304 tubing we use in the W87 pit tube. During surveillance operations, the pit tube undergoes a series of bending and straightening as it goes through a number of surveillance cycles. This motivated the study to characterize austenitic SS304 tubing obtained from Rocky Flats. The tubes continued to display structural soundness even after numerous repeated bending and straightening cycles. The minimum and maximum number of bends to failure occurred after 13 and 16 cycles, respectively. After 5 bends, both the inner and outer surfaces of the tubing showed no microcracks. When the bent tubing samples were pressurized and tested using deuterium at 74{degrees}C and at {approximately}78{degrees}C, they failed away from the bent area. Thus deuterium embrittlement of the bent SS304 tubing should not be a problem. Moreover, to increase our 95% confidence level to 5 bends, we are planning to perform at least four additional bends to failure tests.

  11. 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

  12. [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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 77 FR 13631 - Drawn Stainless Steel Sinks From China; Institution and Scheduling of Preliminary Phase...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Drawn Stainless Steel Sinks From China; Institution and Scheduling of Preliminary Phase... the United States is materially retarded, by reason of imports from China of drawn stainless...

  18. DETECTION OF BACTERIAL BIOFILM ON STAINLESS STEEL BY HYPERSPECTRAL FLUORESCENCE IMAGING

    USDA-ARS?s Scientific Manuscript database

    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...

  19. 75 FR 70908 - Circular Welded Austenitic Stainless Pressure Pipe From the People's Republic of China: Extension...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-19

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF COMMERCE International Trade Administration Circular Welded Austenitic Stainless Pressure Pipe From the People's Republic... of the antidumping duty order on circular welded austenitic stainless pressure pipe from the...

  20. Aluminum and stainless steel tubes joined by simple ring and welding process

    NASA Technical Reports Server (NTRS)

    Townhill, A.

    1967-01-01

    Duranel ring is used to join aluminum and stainless steel tubing. Duranel is a bimetal made up of roll-bonded aluminum and stainless steel. This method of joining the tubing requires only two welding operations.

  1. 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.

  2. Low-temperature creep of austenitic stainless steels

    NASA Astrophysics Data System (ADS)

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

    2017-09-01

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

  3. 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. 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.

  5. 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.

  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. 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.

  9. 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.

  10. Transmission electron microscopy of undermined passive films on stainless steel

    SciTech Connect

    Isaacs, H.S.; Zhu, Y.; Sabatini, R.L.; Ryan, M.P.

    1999-06-01

    A study has been made of the passive film remaining over pits on stainless steel using a high resolution transmission electron microscope. Type 305 stainless steel was passivated in a borate buffer solution and pitted in ferric chloride. Passive films formed at 0.2 V relative to a saturated calomel electrode were found to be amorphous. Films formed at higher potentials showed only broad diffraction rings. The passive film was found to cover a remnant lacy structure formed over pits passivated at 0.8 V. The metallic strands of the lace were roughly hemitubular in shape with the curved surface facing the center of the pit.

  11. Isothermal and Cyclic Aging of 310S Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Parrens, Coralie; Lacaze, Jacques; Malard, Benoit; Dupain, Jean-Luc; Poquillon, Dominique

    2017-06-01

    Unusual damage and high creep strain rates have been observed on components made of 310S stainless steel subjected to thermal cycles between room temperature and 1143 K (870 °C). Microstructural characterization of such components after service evidenced high contents in sigma phase which formed first from δ-ferrite and then from γ-austenite. To get some insight into this microstructural evolution, isothermal and cyclic aging of 310S stainless steel has been studied experimentally and discussed on the basis of numerical simulations. The higher contents of sigma phase observed after cyclic agings than after isothermal treatments are clearly associated with nucleation triggered by thermal cycling.

  12. 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.

  13. Passive Films Formed on Stainless Steels in Phosphate Buffer Solution

    NASA Astrophysics Data System (ADS)

    Méndez, Claudia Marcela; Burgos, Rodrigo Elvio; Bruera, Florencia; Ares, Alicia Esther

    The behaviour of passive films formed on directionally solidified stainless steels, 18Cr10N2Mo0.08C, 18Cr14N8Mo0.03C and 18Cr10Ni8Mo0.08C, in different areas that were formed during solidification (columnar, columnar-to-equiaxed transition (CET) and equiaxed) was studied using electrochemical testing in Na2HPO4 with / without NaCl. The behavior of stainless steel in the presence of phosphate chlorides is the best compared to non-chloride phosphate.

  14. Corrosion evaluation of stainless steel root weld shielding

    SciTech Connect

    Gorog, M.; Sawyer, L.A.

    1999-07-01

    The effect of five shielding methods for gas tungsten arc root pass welds, on the corrosion resistance of stainless steel was evaluated in two laboratory solutions. The first experiment was performed in 6% ferric chloride solution, a test designed to corrode stainless steel. The second experiment was performed in a simulated paper machine white water solution that contained hydrogen peroxide. Argon shielding produced excellent results by maintaining corrosion resistance in both solutions. Nitrogen purging and flux coated TIG rod techniques produced variable results. Paste fluxes and welding without shielding are not recommended for root protection. They performed very poorly with the welds corroding in both tests.

  15. 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.

  16. Microstructure and texture of Nb + Ti stabilized ferritic stainless steel

    SciTech Connect

    Yan Haitao Bi Hongyun; Li Xin; Xu Zhou

    2008-12-15

    The microstructure, texture and grain boundary character distribution of Nb + Ti stabilized ferritic stainless steel were analyzed using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The addition of alloying elements such as Ti and Nb to ferritic stainless steel causes the formation of TiN, NbC and Fe{sub 2}Nb. The textures of cold rolled samples were dominated by the {alpha}-fiber, while the textures of annealed samples exhibit a very strong {gamma}-fiber. The changes in texture are closely related to the grain boundary characteristics.

  17. Calculations of Stainless Steel-Aluminum Alloy Clad Forming Limit

    NASA Astrophysics Data System (ADS)

    Liu, Hongwei; Zhang, Peng

    Base on the Hosford's higher order yield criteria, the forming limit diagram of clad was developed with M-K theory at the positive strain ratio. The relationship of forming limit with thickness ratio, thickness irregular coefficient and the exponent of yield function were analyzed. The result show that the forming limit of clad material is between those of its component materials, and increases with the rising of stainless steel thickness ratio and the thickness irregular coefficient. So the forming limit can be improved by increase the stainless steel thickness ratio and improve the surface condition of the clad materials.

  18. 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

  19. 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.

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  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. 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...

  7. 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,...

  8. 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...

  9. 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...

  10. 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:...

  11. 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,...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 75 FR 62624 - WTO Dispute Settlement Proceeding Regarding United States-Final Antidumping Measures on Stainless...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-12

    ... Measures on Stainless Steel from Mexico AGENCY: Office of the United States Trade Representative. ACTION... Stainless Steel from Mexico to a panel. The request may be found at http://www.wto.org in document WT/DS344... Stainless Steel from Mexico. The recommendations and rulings stem from the DSB's adoption of the panel...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. The Cold Gas-Dynamic Spray and Characterization of Microcrystalline Austenitic Stainless Steel

    DTIC Science & Technology

    2014-09-01

    DYNAMIC SPRAY AND CHARACTERIZATION OF MICROCRYSTALLINE AUSTENITIC STAINLESS STEEL by Jonathan F. Schiel September 2014 Thesis Advisor: Luke...MICROCRYSTALLINE AUSTENITIC STAINLESS STEEL 5. FUNDING NUMBERS DWAM31009 6. AUTHOR(S) Jonathan F. Schiel 7. PERFORMING ORGANIZATION NAME(S...spray process applied to the deposition of stainless steel coatings. Cold spray deposition is a relatively new process utilized to create corrosion

  4. 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, Korea...

  5. 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 to...

  6. 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... Korea and the antidumping duty orders on stainless steel sheet and strip from Germany, Italy, Japan... antidumping duty orders on stainless steel sheet and strip from Germany, Italy, Japan, Korea, Mexico, and...

  7. 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. ACTION: Institution of five-year reviews concerning the countervailing duty orders on stainless 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 and...

  8. 78 FR 62583 - Welded Stainless Pressure Pipe From Malaysia, Thailand, and the Socialist Republic of Vietnam...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-22

    ... International Trade Administration Welded Stainless Pressure Pipe From Malaysia, Thailand, and the Socialist... stainless pressure pipe from Malaysia, Thailand, and the Socialist Republic of Vietnam.\\1\\ The notice of... Welded Stainless Pressure Pipe From Malaysia, Thailand, and the Socialist Republic of Vietnam:...

  9. 76 FR 43981 - Circular Welded Austenitic Stainless Pressure Pipe From the People's Republic of China: Final...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ... International Trade Administration Circular Welded Austenitic Stainless Pressure Pipe From the People's Republic... antidumping duty order on circular welded austenitic stainless pressure pipe from the People's Republic of..., 2010. \\1\\ See Circular Welded Austenitic Stainless Pressure Pipe From the People's Republic of...

  10. 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...

  11. 76 FR 17819 - Circular Welded Austenitic Stainless Pressure Pipe From the People's Republic of China...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-31

    ... International Trade Administration Circular Welded Austenitic Stainless Pressure Pipe From the People's Republic... ] antidumping duty order on circular welded austenitic stainless pressure pipe (``austenitic pipe'') from the... Stainless Pressure Pipe from the People's Republic of China, 74 FR 11351 (March 17, 2009). \\2\\...

  12. Fabrication of stainless steel foil utilizing chromized steel strip

    NASA Astrophysics Data System (ADS)

    Loria, Edward A.

    1980-10-01

    Stainless steel foil has properties which are, in many respects, unmatched by alternative thin films. The high strength to weight ratio and resistance to corrosion and oxidation at elevated temperatures are generally advantageous. The aerospace and automotive industries have used Type 430 and 304 foil in turbine engine applications. Foil around 2 mils (5.1 × 10-3 cm) thick has been appropriate for the recuperator or heat exchanger and this product has also been used in honeycomb and truss-core structures. Further, such foil has been employed as a wrap to protect tool steel parts from contamination during heat treating. A large part of the high cost of producing stainless steel foil by rolling is due to the complicated and expensive rolling mill and annealing equipment involved. A method will be described which produces (solid) stainless steel foil from chromized (coated) steel which can be cheaper than the conventional processing stainless steel, such as Type 430, from ingot to foil. Also, the material is more ductile and less work hardenable during processing to foil and consequently intermediate annealing treatments are eliminated and scrap losses minimized.

  13. 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.

  14. 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.

  15. Stainless Steel Crown Placement Utilizing the Hall Technique

    DTIC Science & Technology

    2017-03-23

    FROM: 59 MDW/SGVU SUBJECT: Professional Presentation Approval 8 MAR 2017 1. Your paper, entitled Stainless Steel Crown Placement Utilizing the Hall...Lenox Pointe NE, Atlanta, GA 30324; 23-25 MAR 20 17 D 11e. OTHER (Describe: name of meeting, city, state, and date of meeting.) 12. EXPECTED DATE

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Brazing of Stainless Steel to Various Aluminum Alloys in Air

    NASA Astrophysics Data System (ADS)

    Liu, Shuying; Suzumura, Akio; Ikeshoji, Toshi-Taka; Yamazaki, Takahisa

    Brazing of a stainless steel to various aluminum alloys was carried out using an Al-Si filler metal and a fluoride-active flux in air. The brazeability was remarkably different by the aluminum alloys and the brazing conditions. It was considered that the differences were originated with the compositions of base metals and the filler metal, the solidus temperature and the partially melting behavior of the aluminum alloys, and the behavior of the surface oxide film layers of both base metals. On the other hand, the obstruction of brazeability was identified as the rapid reaction between the aluminum alloys and the brazing filler metal, which makes the molten brazing filler metal disappear at the joining interface before the wetting occurs to the stainless steel. Taking this phenomena into consideration, it was attempted to make previous wetting of the brazing filler to the stainless steel before brazing to the aluminum alloys. This method provided the successful brazed joints for the most combinations of the stainless steel and the aluminum alloys.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  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. Plastic plus stainless-steel fibers make resilient, impermeable material

    NASA Technical Reports Server (NTRS)

    Smirra, J. R.

    1965-01-01

    Plastic material combined with stainless-steel fibers and molded under heat and pressure into a desired configuration is both soft enough to deform under a load and resilient enough to return to its original shape when the load is removed.

  12. 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.

  13. Nanoparticle treated stainless steel filters for metal vapor sequestration

    SciTech Connect

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

    2016-12-07

    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. Furthermore, 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.

  14. Nanoparticle treated stainless steel filters for metal vapor sequestration

    DOE PAGES

    Murph, Simona E. Hunyadi; Larsen, George K.; Korinko, Paul; ...

    2016-12-07

    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 ontomore » 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. Furthermore, 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.« less

  15. [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.

  16. 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

  17. 2. GENERAL VIEW OF STAINLESS STEEL SMOKEHOUSES ON LEVEL 6, ...

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

    2. GENERAL VIEW OF STAINLESS STEEL SMOKEHOUSES ON LEVEL 6, LOOKING EAST; SMOKEHOUSE UNITS WERE BUILT BY DRYING SYSTEMS COMPANY, DIVISION OF MICHIGAN OVEN COMPANY, MORTON GROVE, ILLINOIS - Rath Packing Company, Smokehouse-Hog Chilling Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  18. Electrochemically induced annealing of stainless-steel surfaces.

    PubMed

    Burstein, G T; Hutchings, I M; Sasaki, K

    2000-10-19

    Modification of the surface properties of metals without affecting their bulk properties is of technological interest in demanding applications where surface stability and hardness are important. When austenitic stainless steel is heavily plastically deformed by grinding or rolling, a martensitic phase transformation occurs that causes significant changes in the bulk and surface mechanical properties of the alloy. This martensitic phase can also be generated in stainless-steel surfaces by cathodic charging, as a consequence of lattice strain generated by absorbed hydrogen. Heat treatment of the steel to temperatures of several hundred degrees can result in loss of the martensitic structure, but this alters the bulk properties of the alloy. Here we show that martensitic structures in stainless steel can be removed by appropriate electrochemical treatment in aqueous solutions at much lower temperature than conventional annealing treatments. This electrochemically induced annealing process allows the hardness of cold-worked stainless steels to be maintained, while eliminating the brittle martensitic phase from the surface. Using this approach, we are able to anneal the surface and near-surface regions of specimens that contain rolling-induced martensite throughout their bulk, as well as those containing surface martensite induced by grinding. Although the origin of the electrochemical annealing process still needs further clarification, we expect that this treatment will lead to further development in enhancing the surface properties of metals.

  19. Electrochemically induced annealing of stainless-steel surfaces

    NASA Astrophysics Data System (ADS)

    Burstein, G. T.; Hutchings, I. M.; Sasaki, K.

    2000-10-01

    Modification of the surface properties of metals without affecting their bulk properties is of technological interest in demanding applications where surface stability and hardness are important. When austenitic stainless steel is heavily plastically deformed by grinding or rolling, a martensitic phase transformation occurs that causes significant changes in the bulk and surface mechanical properties of the alloy. This martensitic phase can also be generated in stainless-steel surfaces by cathodic charging, as a consequence of lattice strain generated by absorbed hydrogen. Heat treatment of the steel to temperatures of several hundred degrees can result in loss of the martensitic structure, but this alters the bulk properties of the alloy. Here we show that martensitic structures in stainless steel can be removed by appropriate electrochemical treatment in aqueous solutions at much lower temperature than conventional annealing treatments. This electrochemically induced annealing process allows the hardness of cold-worked stainless steels to be maintained, while eliminating the brittle martensitic phase from the surface. Using this approach, we are able to anneal the surface and near-surface regions of specimens that contain rolling-induced martensite throughout their bulk, as well as those containing surface martensite induced by grinding. Although the origin of the electrochemical annealing process still needs further clarification, we expect that this treatment will lead to further development in enhancing the surface properties of metals.

  20. Simulation Computation of 430 Ferritic Stainless Steel Solidification

    NASA Astrophysics Data System (ADS)

    Pang, Ruipeng; Li, Changrong; Wang, Fuming; Hu, Lifu

    The solidification structure of 430 ferritic stainless steel has been calculated in the solidification process by using 3D-CAFE model under the condition of water cooling. The calculated results consistent with those obtained from experiment. Under watercooling condition, the solidification structure consists of chilled layer, columnar grain zone, transition zone and equiaxed grain zone.