WorldWideScience

Sample records for stainless chromium-nickel steels

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

    OpenAIRE

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

    2013-01-01

    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 sau...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  4. Pelepasan ion nikel dan kromium kawat Australia dan stainless steel dalam saliva buatan (The release of nickel and chromium ions from Australian wire and stainless steel in artificial saliva)

    OpenAIRE

    Nolista Indah Rasyid; Pinandi Sri Pudyani; JCP Heryumani

    2014-01-01

    Background: Fixed orthodontic treatment needs several types of wire to produce biomechanical force to move teeth. The use orthodontic wire within the mouth interacts with saliva, causing the release of nickel and chromium ions. Purpose: The study was aimed to examine the effect of immersion time in artificial saliva between special type of Australian wire and stainless steel on the release of nickel and chromium ions. Methods: Thirty special type Australian wires and 30 stainless steel wires ...

  5. Absorption of Nickel, Chromium, and Iron by the Root Surface of Primary Molars Covered with Stainless Steel Crowns

    Directory of Open Access Journals (Sweden)

    David Keinan

    2010-01-01

    Full Text Available Objective. The purpose of this study was to analyze the absorption of metal ions released from stainless steel crowns by root surface of primary molars. Study Design. Laboratory research: The study included 34 primary molars, exfoliated or extracted during routine dental treatment. 17 molars were covered with stainless-steel crowns for more than two years and compared to 17 intact primary molars. Chemical content of the mesial or distal root surface, 1 mm apically to the crown or the cemento-enamel junction (CEJ, was analyzed. An energy dispersive X-ray spectrometer (EDS was used for chemical analysis. Results. Higher amounts of nickel, chromium, and iron (5-6 times were found in the cementum of molars covered with stainless-steel crowns compared to intact molars. The differences between groups were highly significant (<.001. Significance. Stainless-steel crowns release nickel, chromium, and iron in oral environment, and the ions are absorbed by the primary molars roots. The additional burden of allergenic metals should be reduced if possible.

  6. Pelepasan ion nikel dan kromium kawat Australia dan stainless steel dalam saliva buatan (The release of nickel and chromium ions from Australian wire and stainless steel in artificial saliva

    Directory of Open Access Journals (Sweden)

    Nolista Indah Rasyid

    2014-09-01

    Full Text Available Background: Fixed orthodontic treatment needs several types of wire to produce biomechanical force to move teeth. The use orthodontic wire within the mouth interacts with saliva, causing the release of nickel and chromium ions. Purpose: The study was aimed to examine the effect of immersion time in artificial saliva between special type of Australian wire and stainless steel on the release of nickel and chromium ions. Methods: Thirty special type Australian wires and 30 stainless steel wires were used in this study, each of which weighed 0.12 grams. The wires were immersed for 1, 7, 28, 35, 42, and 49 days in artificial saliva with a normal pH. The release of ions in saliva was examined using Atomic Absorption spectrophotometry. Results: The result indicated that the release of nickel ions on special type of Australian wire was larger than that on stainless steel wire (p<0.005, there were differences in the release of the amount of nickel ions on special type of Australia in different immersion time, and there was a correlation between the types of wire and immersion time. Nickel ions released from the special type of Australian wire detected on the 7th day of immersion and reached its peak on the 35th day, while from stainless steel wire were detected on the 49th day of immersion. The released of chromium ions from the special type of Australian wire and stainless steel wire were not detected until the 49th day of immersion. Conclusion: The release of nickel ions were highest on the 35th day of immersion in special type of Australian wire and they were detected on the 49th day in stainless steel wire. The release of chromium ions were not detected until 49th day of immersion in special type of Australian and stainless steel wire.Latar belakang: Perawatan ortodonti cekat memerlukan beberapa macam kawat untuk menghasilkan kekuatan biomekanika yang sesuai dalam menggerakkan gigi. Pemakaian kawat ortodonti di dalam mulut dapat bereaksi dengan

  7. Nickel and chromium ion release from stainless steel bracket on immersion various types of mouthwashes

    Science.gov (United States)

    Mihardjanti, M.; Ismah, N.; Purwanegara, M. K.

    2017-08-01

    The stainless steel bracket is widely used in orthodontics because of its mechanical properties, strength, and good biocompatibility. However, under certain conditions, it can be susceptible to corrosion. Studies have reported that the release of nickel and chromium ions because of corrosion can cause allergic reactions in some individuals and are mutagenic. The condition of the oral environment can lead to corrosion, and one factor that can alter the oral environment is mouthwash. The aim of this study was to measure the nickel and chromium ions released from stainless steel brackets when immersed in mouthwash and aquadest. The objects consisted of four groups of 17 maxillary premolar brackets with .022 slots. Each group was immersed in a different mouthwash and aquadest and incubated at 37 °C for 30 days. After 30 days of immersion, the released ions were measured using the ICP-MS (Inductively Coupled Plasma-Mass Spectrometer). For statistical analysis, both the Kruskal-Wallis and Mann-Whitney tests were used. The results showed differences among the four groups in the nickel ions released (p < 0.05) and the chromium ions released (p < 0.5). In conclusion, the ions released as a result of mouthwash immersion have a small value that is below the limit of daily intake recommended by the World Health Organization.

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

    Science.gov (United States)

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

    2013-10-01

    The field of biomaterials has become a vital area, as these materials can enhance the quality and longevity of human life. Metallic materials are often used as biomaterials to replace structural components of the human body. Stainless steels, cobalt-chromium alloys, commercially pure titanium and its alloys are typical metallic biomaterials that are being used for implant devices. Stainless steels have been widely used as biomaterials because of their very low cost as compared to other metallic materials, good mechanical and corrosion resistant properties and adequate biocompatibility. However, the adverse effects of nickel ions being released into the human body have promoted the development of "nickel-free nitrogen containing austenitic stainless steels" for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel and emphatically the advantages of nitrogen in stainless steel, as well as the development of nickel-free nitrogen containing stainless steels for medical applications. By combining the benefits of stable austenitic structure, high strength, better corrosion and wear resistance and superior biocompatibility in comparison to the currently used austenitic stainless steel (e.g. 316L), the newly developed nickel-free high nitrogen austenitic stainless steel is a reliable substitute for the conventionally used medical stainless steels. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes are normally used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0% and nickel does not exceed 50.0%

  10. Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes are normally used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

  11. Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes normally are used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium-nickel steels in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

  12. Effect of Low Nickel Dopant on Torque Transducer Response Function in High-Chromium Content ESR Stainless Tool Steels

    Science.gov (United States)

    Wiewel, Joseph L.; Hecox, Bryan G.; Orris, Jason T.; Boley, Mark S.

    2007-03-01

    The change in magnetoelastic torque transducer response was investigated as a low nickel content (up to 0.2%) is alloyed into an ESR (Electro-Slag-Refining) stainless tool steel with a chromium content of around 13%, which our previous studies have proven to be the ideal level of chromium content for optimal transducer performance. Two separate hollow steel 3/4-inch diameter shafts were prepared from ESR 416 and ESR 420 steel, respectively, the first having no nickel content and the second having 0.2% nickel content. The heat treatment of these steels consisted of a hardening process conducted in a helium atmosphere at 1038^oC, followed by an annealing at 871^oC for 5h and a 15^oC cool down rate. Prior and subsequent to the heat treatment processes, the circumferential and axial magnetic hysteresis properties of the samples were measured and their external field signals were mapped over the magnetically polarized regions both with and without applied shear stress up to 2500 psi on the samples. It was found that the effect of the low nickel dopant was to improve torque transducer sensitivity and linearity, but heat treatment worsened the performance of both samples.

  13. Monitoring of occupational exposure in manufacturing of stainless steel constructions. Part I: Chromium, iron, manganese, molybdenum, nickel and vanadium in the workplace air of stainless steel welders.

    Science.gov (United States)

    Kucera, J; Bencko, V; Pápayová, A; Saligová, D; Tejral, J; Borská, L

    2001-11-01

    Exposure to workplace airborne pollutants was examined in a group of 20 workers dealing mainly with welding, polishing, drilling and assembling of stainless steel constructions. Airborne particulate matter (APM) collected using both personal and stationary samplers was analyzed by instrumental neutron activation analysis (INAA). Quality assurance procedures of both sampling and analytical stages are described. Of the elements determined, results are presented for chromium, iron, manganese, molybdenum, nickel and vanadium. The median values of element concentrations exceeded the maximum admissible limits for workplace pollutants only for chromium, while for nickel the limit was exceeded in several individual cases. Sampling of hair, nails, blood, urine and saliva to be used for biological monitoring of the exposed and control groups is also described.

  14. Austenitic stainless steel alloys with high nickel contents in high temperature liquid metal systems

    International Nuclear Information System (INIS)

    Konvicka, H.R.; Schwarz, N.F.

    1981-01-01

    Fe-Cr-Ni base alloys (nickel content: from 15 to 70 wt%, Chromium content: 15 wt%, iron: balance) together with stainless steel (W.Nr. 1.4981) have been exposed to flowing liquid sodium at 730 0 C in four intervals up to a cumulative exposure time of 1500 hours. Weight change data and the results of post-exposition microcharacterization of specimens are reported. The corrosion rates increase with increasing nickel content and tend to become constant after longer exposure times for each alloy. The corrosion rate of stainless steel is considerably reduced due to the presence of the base alloys. Different kinetics of nickel poor (up to 35% nickel) and nickel rich (> 50% nickel) alloys and nickel transport from nickel rich to nickel poor material is observed. (orig.)

  15. Stress corrosion cracking of austenitic stainless steels in high temperature water and alternative stainless steel

    International Nuclear Information System (INIS)

    Yonezawa, T.

    2015-01-01

    In order to clarify the effect of SFE on SCC resistance of austenitic stainless steels and to develop the alternative material of Type 316LN stainless steel for BWR application, the effect of chemical composition and heat treatment on SFE value and SCCGR in oxygenated high temperature water were studied. The correlation factors between SFE values for 54 heats of materials and their chemical compositions for nickel, molybdenum, chromium, manganese, nitrogen, silicon and carbon were obtained. From these correlation factors, original formulae for SFE values calculation of austenitic stainless steels in the SHTWC, SHTFC and AGG conditions were established. The maximum crack length, average crack length and cracked area of the IGSCC for 33 heats were evaluated as IGSCC resistance in oxygenated high temperature water. The IGSCC resistance of strain hardened nonsensitized austenitic stainless steels in oxygenated high temperature water increases with increasing of nickel contents and SFE values. From this study, it is suggested that the SFE value is a key parameter for the IGSCC resistance of non-sensitized strain hardened austenitic stainless steels. As an alternative material of Type 316LN stainless steel, increased SFE value material, which is high nickel, high chromium, low silicon and low nitrogen material, is recommendable. (author)

  16. Nickel: makes stainless steel strong

    Science.gov (United States)

    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.

  17. On the rational alloying of structural chromium-nickel steels

    International Nuclear Information System (INIS)

    Astaf'ev, A.A.

    1982-01-01

    A study was made on the influence of chromium nickel, phosphorus on the critical brittleness temperature of Cr-Ni-Mo-V structural steels. It is shown that the critical brittleness temperature of these steels increases at chromium content more over than 2% and nickel content more than 2% in the result of carbide transformations during tempering. Increase of nickel content in Cr-Ni-Mo-V-steels strengthens the tendency to embrittlement during slow cooling, from tempering temperature owing to development of process of phosphorus grain-boundary segregation. Two mentioned mechanisms of embrittlement determine principles of rational steel alloying. The extreme dependence of the critical brittleness temperature on chromium and nickel content, which enables to choose the optimum composition of Cr-Ni-Mo-V-steels, was established

  18. Specification for corrosion-resisting chromium and chromium-nickel steel welding rods and bare electrodes - approved 1969

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    This specification covers corrosion-resisting chromium and chromium-nickel steel welding rods for use with the atomic hydrogen and gas-tungsten-arc welding processes and bare electrodes for use with the submerged arc and gas metal-arc welding processes. These welding rods and electrodes include those alloy steels designated as corrosion- or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4% and nickel does not exceed 50%

  19. Chromium-Makes stainless steel stainless

    Science.gov (United States)

    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.

  20. Relationship between equivalent chromium content and irradiation-induced swelling in 316 stainless steel

    International Nuclear Information System (INIS)

    Bates, J.F.; Guthrie, G.L.

    1974-12-01

    A correlation is noted between equivalent chromium content and resistance to irradiation induced swelling in various 316 stainless steel specimens which have slightly different chemical compositions. Several examples are cited where an increased concentration of an α-stabilizing minor constituent results in decreased swelling. It is shown that the relative swelling resistance of alloys having the same carbon and equivalent nickel contents is higher for those alloys with the higher equivalent chromium content

  1. Chromium in aqueous nitrate plutonium process streams: Corrosion of 316 stainless steel and chromium speciation

    International Nuclear Information System (INIS)

    Smith, W.H.; Purdy, G.M.

    1995-01-01

    This study was undertaken to determine if chromium(+6) could exist in plutonium process solutions under normal operating conditions. Four individual reactions were studied: the rate of dissolution of stainless steel, which is the principal source of chromium in process solutions; the rate of oxidation of chromium(+3) to chromium(+6) by nitric acid; and the reduction of chromium(+6) back to chromium(+3) by reaction with stainless steel and with oxalic acid. The stainless steel corrosion rate was found to increase with increasing nitric acid concentration, increasing hydrofluoric acid concentration, and increasing temperature. Oxidation of chromium(+3) to chromium(+6) was negligible at room temperature and only became significant in hot concentrated nitric acid. The rate of reduction of chromium(+6) back to chromium(+3) by reaction with stainless steel or oxalic acid was found to be much greater than the rate of the reverse oxidation reaction. Based on these findings and taking into account normal operating conditions, it was determined that although there would be considerable chromium in plutonium process streams it would rarely be found in the (+6) oxidation state and would not exist in the (+6) state in the final process waste solutions

  2. Chromium in aqueous nitrate plutonium process streams: Corrosion of 316 stainless steel and chromium speciation

    International Nuclear Information System (INIS)

    Smith, W.H.; Purdy, G.

    1995-01-01

    This study was undertaken to determine if chromium +6 could exist in plutonium process solutions under normal operating conditions. Four individual reactions were studied: the rate of dissolution of stainless steel, which is the principal source of chromium in process solutions; the rate of oxidation of chromium +3 to chromium +6 by nitric. acid; and the reduction of chromium +6 back to chromium +3 by reaction with stainless steel and with oxalic acid. The stainless steel corrosion rate was found to increase with increasing nitric acid concentration, increasing hydrofluoric acid concentration, and increasing temperature. Oxidation of chromium +3 to chromium +6 was negligible at room temperature and only became significant in hot concentrated nitric acid. The rate of reduction of chromium +6 back to chromium +3 by reaction with stainless steel or oxalic acid was found to be much greater than the rate of the reverse oxidation reaction. Based on these findings and taking into account normal operating conditions, it was determined that although there would be considerable chromium in plutonium process streams it would rarely be found in the +6 oxidation state and would not exist in the +6 state in the final process waste solutions

  3. Discontinuous precipitation in a nickel-free high nitrogen austenitic stainless steel on solution nitriding

    DEFF Research Database (Denmark)

    Mohammadzadeh, Roghayeh; Akbari, Alireza; Grumsen, Flemming Bjerg

    2017-01-01

    Chromium-rich nitride precipitates in production of nickel-free austenitic stainless steel plates via pressurised solution nitriding of Fe–22.7Cr–2.4Mo ferritic stainless steel at 1473 K (1200 °C) under a nitrogen gas atmosphere was investigated. The microstructure, chemical and phase composition......, morphology and crystallographic orientation between the resulted austenite and precipitates were investigated using optical microscopy, X-ray Diffraction (XRD), Scanning and Transmission Electron Microscopy (TEM) and Electron Back Scatter Diffraction (EBSD). On prolonged nitriding, Chromium-rich nitride...... precipitates were formed firstly close to the surface and later throughout the sample with austenitic structure. Chromium-rich nitride precipitates with a rod or strip-like morphology was developed by a discontinuous cellular precipitation mechanism. STEM-EDS analysis demonstrated partitioning of metallic...

  4. Chromium depletion from stainless steels during vacuum annealing

    International Nuclear Information System (INIS)

    Smith, A.F.; Hales, R.

    1977-01-01

    During selective chromium oxidation of stainless steels the changes in chromium concentration at the metal surface and in the metal have an important bearing on the overall oxidation performance. It has been proposed that an analogue of chromium behaviour during selective oxidation is obtained from volatilisation of chromium during high temperature vacuum annealing. In the present report the evaporation of chromium from 316 type of steel, vacuum annealed at 1,000 0 C, has been investigated by means of energy dispersive X-ray analysis and by neutron activation analysis. It was established that chromium loss from austenitic stainless steels is rate controlled by interdiffusion in the alloy. As predicted the chromium concentration at the metal surface decreased with increasing vacuum annealing time. The chromium depletion profile in the metal was in good agreement with the previously derived model apart from an anomalous region near the surface. Here the higher resolution of the neutron activation technique indicated a zone within approximately 2μm of the surface where the chromium concentration decreased more steeply than expected. (orig.) [de

  5. Comparison of nickel and chromium ions released from stainless steel and NiTi wires after immersion in Oral B®, Orthokin® and artificial saliva.

    Science.gov (United States)

    Jamilian, Abdolreza; Moghaddas, Omid; Toopchi, Shabnam; Perillo, Letizia

    2014-07-01

    Oral environment of the mouth is a suitable place for biodegradation of alloys used in orthodontic wires. The toxicity of these alloys namely nickel and chromium has concerned the researchers about the release of these ions from orthodontic wires and brackets. The aim of this study was to measure the levels of nickel and chromium ions released from 0.018" stainless steel (SS) and NiTi wires after immersion in three solutions. One hundred and forty-four round NiTi and 144 round SS archwires with the diameters of 0.018" were immersed in Oral B®, Orthokin® and artificial saliva. The amounts of nickel and chromium ions released were measured after 1, 6, 24 hours and 7 days. Two way repeated ANOVA showed that the amount of chromium and nickel significantly increased in all solutions during all time intervals (p nickel ions were released more in NiTi wire in all solutions compared with SS wire. The lowest increase rate was also seen in artificial saliva. There is general consensus in literature that even very little amounts of nickel and chromium are dangerous for human body specially when absorbed orally; therefore, knowing the precise amount of these ions released from different wires when immersed in different mouthwashes is of high priority.

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

    Energy Technology Data Exchange (ETDEWEB)

    Pistorius, P Chris; Li, Wen

    2012-09-19

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

  7. Nickel alloys and high-alloyed special stainless steels. Properties, manufacturing, applications. 4. compl. rev. ed.

    International Nuclear Information System (INIS)

    Heubner, Ulrich; Kloewer, Jutta; Alves, Helena; Behrens, Rainer; Schindler, Claudius; Wahl, Volker; Wolf, Martin

    2012-01-01

    This book contains the following eight topics: 1. Nickel alloys and high-alloy special stainless steels - Material overview and metallurgical principles (U. Heubner); 2. Corrosion resistance of nickel alloys and high-alloy special stainless steels (U. Heubner); 3. Welding of nickel alloys and high-alloy special stainless steels (T. Hoffmann, M. Wolf); 4. High-temperature materials for industrial plant construction (J. Kloewer); 5. Nickel alloys and high-alloy special stainless steels as hot roll clad composites-a cost-effective alternative (C. Schindler); 6. Selected examples of the use of nickel alloys and high-alloy special stainless steels in chemical plants (H. Alves); 7. The use of nickel alloys and stainless steels in environmental engineering (V. Wahl); 8: Nickel alloys and high-alloy special stainless steels for the oil and gas industry (R. Behrens).

  8. Specification for corrosion-resisting chromium and chromium-nickel steel bare and composite metal cored and stranded arc welding electrodes and welding rods

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    This specification prescribes requirements for corrosion or heat resisting chromium and chromium-nickel steel electrodes and welding rods. These electrodes and welding rods are normally used for arc welding and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

  9. A comparison of the iraddiated tensile properties of a high-manganese austenitic steel and type 316 stainless steel

    International Nuclear Information System (INIS)

    Klueh, R.L.; Grossbeck, M.L.

    1984-01-01

    The USSR steel EP-838 is a high-manganese, low-nickel steel that also has lower chromium and molybdenum than type 316 stainless steel. Tensile specimens of 20%-cold-worked EP-838 and type 316 stainless steel were irradiated in the High Flux Isotope Reactor (HFIR) at the coolant temperature (approx.=50 0 C). A displacement damage level of 5.2 dpa was reached for the EP-838 and up to 9.5 dpa for the type 316 stainless steel. Tensile tests at room temperature and 300 0 C on the two steels indicated that the irradiation led to increased strength and decreased ductility compared to the unirradiated steels. Although the 0.2% yield stress of the type 316 stainless steel in the unirradiated condition was greater than that for the EP-838, after irradiation there was essentially no difference between the strength or ductility of the two steels. The results indicate that the replacement of the majority of the nickel by manganese and a reduction of chromium and molybdenum in an austenitic stainless steel of composition near that for type 316 stainless steel has little effect on the irradiated and unirradiated tensile properties at low temperatures. (orig.)

  10. Changes in structure and phase composition of chromium diffusion layer on stainless steels after long annealing

    International Nuclear Information System (INIS)

    Knyazev, E.V.; Voshedchenko, B.M.; Voskresenskij, Yu.A.

    1985-01-01

    A study was made on the effect of elevated temperatures UU and long holdings at heat on structure, phase composition and properties of chromium diffusion layer on austenitic chromium-nickel stainless steels 10Kh18N10TVD, 10Kh15N30M4B, 10Kh11N23T3MR, 10Kh21N28V6M3. The following mechanism of processes taking place in diffusion chromium layer is presented. The steady drop of chromium concentrations is observed after diffusion saturation. Chromium redistribution related with system transformation to more equilibrium state and simultaneous decarburization of steel surfaces takes place in diffusion layers of 10Kh15N30M4B and 10Kh21N28V6M3 steels after annealing at different temperatures and holdings at heat. Decarburization of steel surface layers is practically excluded in diffusion layers of 10Kh18N10T-VD and 10Kh11N23T3MR steels. Diffusion chromium-saturated layer stays effective only on 10Kh18N10T-VD and 10Kh11N23T3MR steels on heating up to 1000 deq C with holding up to 250 h

  11. Corrosion of nickel and stainless steels in concentrated lithium hydroxide solutions

    International Nuclear Information System (INIS)

    Graydon, J.W.; Kirk, D.W.

    1990-06-01

    The corrosion behaviour of four alloys in 3 and 5 mol/L lithium hydroxide solutions under a hydrogen atmosphere at 95 degrees C was investigated. Corrosion of Nickel 200 and the stainless steels 316, 316L, and E-Brite 26-1 was assessed in two sets of immersion tests lasting 10 and 136 days. Corrosion rates were determined by weight loss, susceptibility to stress corrosion cracking was evaluated using U-bends, and the details of the corrosion process were studied on specimens with a mirror finish using light and electron microscopy, x-ray spectrometry and mapping, and x-ray diffraction. The long term corrosion rates were low for all alloys ( 2 , β-LiFeO 2 , and a very iron-rich β-LiFe 5 0 8 . The passivating layer on the nickel was Ni(OH) 2 . The underlying metal corroded evenly except for the 316 stainless steels. These showed a uniform intergranular corrosion with minor drop-out of smaller grains likely because of segregation of impurities to the grain boundaries. The walls of these intergranular crevices were covered with a passivating layer of chromium oxide. (8 figs., 5 tabs., 11 refs.)

  12. Optimized chemical composition, working and heat treatment condition for resistance to irradiation assisted stress corrosion cracking of cold worked 316 and high-chromium austenitic stainless steel

    International Nuclear Information System (INIS)

    Yonezawa, Toshio; Iwamura, Toshihiko; Fujimoto, Koji; Ajiki, Kazuhide

    2000-01-01

    The authors have reported that the primary water stress corrosion cracking (PWSCC) in baffle former bolts made of austenitic stainless steels for PWR after long-term operation is caused by irradiation-induced grain boundary segregation. The resistance to PWSCC of simulated austenitic stainless steels whose chemical compositions are simulated to the grain boundary chemical composition of 316 stainless steel after irradiation increased with decrease of the silicon content, increases of the chromium content, and precipitation of M 23 C 6 carbides at the grain boundaries. In order to develop resistance to irradiation assisted stress corrosion cracking in austenitic stainless steels, optimized chemical compositions and heat treatment conditions for 316CW and high-chromium austenitic stainless steels for PWR baffle former bolts were investigated. For 316CW stainless steel, ultra-low-impurities and high-chromium content are beneficial. About 20% cold working before aging and after solution treatment has also been recommended to recover sensitization and make M 23 C 6 carbides coherent with the matrix at the grain boundaries. Heating at 700 to 725degC for 20 to 50 h was selected as a suitable aging procedure. Cold working of 5 to 10% after aging produced the required mechanical properties. The optimized composition of the high-chromium austenitic stainless steel contents 30% chromium, 30% nickel, and ultra-low impurity levels. This composition also reduces the difference between its thermal expansion coefficient and that of 304 stainless steel for baffle plates. Aging at 700 to 725degC for longer than 40 h and cold working of 10 to 15% after aging were selected to meet mechanical property specifications. (author)

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

    Science.gov (United States)

    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.

  14. Discontinuous precipitation in a nickel-free high nitrogen austenitic stainless steel on solution nitriding

    Science.gov (United States)

    Mohammadzadeh, Roghayeh; Akbari, Alireza; Grumsen, Flemming B.; Somers, Marcel A. J.

    2017-10-01

    Chromium-rich nitride precipitates in production of nickel-free austenitic stainless steel plates via pressurised solution nitriding of Fe-22.7Cr-2.4Mo ferritic stainless steel at 1473 K (1200 °C) under a nitrogen gas atmosphere was investigated. The microstructure, chemical and phase composition, morphology and crystallographic orientation between the resulted austenite and precipitates were investigated using optical microscopy, X-ray Diffraction (XRD), Scanning and Transmission Electron Microscopy (TEM) and Electron Back Scatter Diffraction (EBSD). On prolonged nitriding, Chromium-rich nitride precipitates were formed firstly close to the surface and later throughout the sample with austenitic structure. Chromium-rich nitride precipitates with a rod or strip-like morphology was developed by a discontinuous cellular precipitation mechanism. STEM-EDS analysis demonstrated partitioning of metallic elements between austenite and nitrides, with chromium contents of about 80 wt.% in the precipitates. XRD analysis indicated that the Chromium-rich nitride precipitates are hexagonal (Cr, Mo)2N. Based on the TEM studies, (Cr, Mo)2N precipitates presented a (1 1 1)γ//(0 0 2)(Cr, Mo)2N, ?γ//?(Cr, Mo)2N orientation relationship with respect to the austenite matrix. EBSD studies revealed that the austenite in the regions that have transformed into austenite and (Cr, Mo)2N have no orientation relation to the untransformed austenite.

  15. Nickel-based materials and high-alloy, special stainless steels. 2. new rev. and enl. ed.

    International Nuclear Information System (INIS)

    Heubner, U.; Brill, U.; Hoffmann, T.; Jasner, M.; Kirchheiner, R.; Koecher, R.; Richter, H.; Rockel, M.; White, F.

    1993-01-01

    The book is intended as a source of information on nickel-based materials and special stainless steels and apart from the up-to-date materials data presents information on recent developments and knowledge gained, so that it may be a valuable aid to materials engineers looking for cost-effective resolutions of their materials problems in the chemical process industry, power plant operation, and high-temperature applications. The book presents eight individual contributions entitled as follows: (1) Nickel-base alloys and high-alloy, special stainless steels. - Materials survey and data sheets (Ulrich Heubner). (2) Corrosion of nickel-base alloys and special stainless steels (Manfred Rockel). (3) Welding of nickel-base alloys and high-alloy, special stainless steels (Theo Hoffmann). (4) High-temperature resistant materials (Ulrich Brill). (5) Application and processing of nickel-base materials in the chemical process industry and in pollution abatement equipment (Reiner Koecher). (6) Selected examples of applications of nickel-base materials in chemical plant (Manfred Jasner, Frederick White). (7) Applications of nickel-base alloys and special stainless steels in power plant. (8) The use of nickel-base alloys and stainless steels in pollution abatement processes (R. Kirchheiner). (orig./MM). 151 figs., 226 refs [de

  16. Electroless nickel plating on stainless steels and aluminum

    Science.gov (United States)

    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.

  17. Preplastic strain effect on chromium carbides precipitation of type 316 stainless steel during high-temperature ageing

    International Nuclear Information System (INIS)

    Mao, X.; Zhao, W.

    1992-01-01

    Long exposure of Type 316 stainless steel to elevated temperature (400-900 o C) is known to cause high-temperature embrittlement due to chromium carbides and σ-phase precipitating in grain boundaries. Numerous investigations have been published on the mechanical properties and microstructure changes occurring during such exposure. However, no investigations exist on the preplastic deformation effect on chromium carbide precipitation in the grain matrix and grain boundary during high-temperature ageing of Type 316 stainless steel and then its effects on the room-temperature tensile properties. Since the stainless steel sometimes is deformed before use at high temperatures, it is necessary to study the preplastic strain effect of the stainless steel on the microstructure change and mechanical property change during high-temperature exposure. The purpose of the present investigation was to carry out such a study. The conclusions reached are as follows. First, chromium carbides are precipitated in deformation lines (slip lines) and then the amount of chromium carbides precipitation in the grain boundary is relatively reduced in predeformed stainless steel after ageing. Secondly, plastic strain pretreatments of and subsequent ageing treatments of Type 316 stainless steel can improve its tensile ductility. Finally, secondary cracking of aged stainless steel occurs in a normal tensile test. The secondary cracking can be reduced by adding preplastic strain into the material. (Author)

  18. Microstructural stability of 21-6-9 stainless steel

    International Nuclear Information System (INIS)

    Krenzer, R.W.; Sanderson, E.C.

    1978-01-01

    Two experiments were designed to better define parameters for thermomechanical processing of 21-6-9 stainless steel. This steel is one of the nitrogen-strengthened chromium, manganese, and nickel austenitic stainless steels having mechanical properties that can be improved by a combination of plastic deformation and heat treatments. By heat-treating coupons, the time-temperature relationship of the precipitate phase, and the solutionizing, recrystallizing, and stress-relieving temperature ranges in 21-6-9 were established. Secondly, mechanical properties and microstructure as a function of percent deformation and stress-relieving temperature are reported

  19. Ductility of high chromium stainless steels

    International Nuclear Information System (INIS)

    Peretyat'ko, V.N.; Kazantsev, A.A.

    1997-01-01

    Aimed to optimize the hot working conditions for high chromium stainless steels the experiments were carried in the temperature range of 800-1300 deg C using hot torsion tests and cylindrical specimens of ferritic and ferritic-martensitic steels 08Kh13, 12Kh13, 20Kh13, 30Kh13 and 40Kh13. Testing results showed that steel plasticity varies in a wide range depending on carbon content. Steels of lesser carbon concentration (08Kh13 and 12Kh13) exhibit a sharp increase in plasticity with a temperature rise, especially in the interval of 1200-1250 deg C. Steels 20Kh13 and 30Kh13 display insignificant plasticity increasing, whereas plastic properties of steel 40Kh13 increase noticeably in the range of 1000-1300 deg C. It is shown that optimal hot working conditions for specific steel must be selected with account of steel phase composition at high temperatures

  20. Corrosion behaviour of high chromium ferritic stainless steels

    International Nuclear Information System (INIS)

    Kiesheyer, H.; Lennartz, G.; Brandis, H.

    1976-01-01

    Ferritic steels developed for seawater desalination and containing 20 to 28% chromium, up to 5% Mo and additions of nickel and copper have been tested with respect to their corrosion behaviour, in particular in chloride containing media. The materials in the sensibilized state were tested for intercrystalline corrosion susceptibility in the Strauss-, Streicher-, nitric acid hydrofluoric acid- and Huey-Tests. No intercrystalline corrosion was encountered in the case of the steels with 28% Cr and 2% Mo. The resistance to pitting was assessed on the basis of rupture potentials determined by potentiokinetic tests. The resistance of the steels with 20% Cr and 5% Mo or 28% Cr and 2% Mo is superior to that of the molybdenum containing austenitic types. Addition of nickel yields a significant increase in crevice corrosion resistance; the same applies to resistance in sulfuric acid. In boiling seawater all the materials tested are resistant to stress corrosion cracking. No sign of any type of corrosion was found on nickel containing steels after about 6,000 hours exposure to boiling 50% seawater brine even under salt deposits. (orig.) [de

  1. Austenitic stainless steels with cryogenic resistance

    International Nuclear Information System (INIS)

    Tarata, Daniela Florentina

    1999-01-01

    The most used austenitic stainless steels are alloyed with chromium and nickel and have a reduced carbon content, usually lower than 0.1 % what ensures corresponding properties for processing by plastic deformation at welding, corrosion resistance in aggressive environment and toughness at low temperatures. Steels of this kind alloyed with manganese are also used to reduce the nickel content. By alloying with manganese which is a gammageneous element one ensures the stability of austenites. Being cheaper these steels may be used extensively for components and equipment used in cryogenics field. The best results were obtained with steels of second group, AMnNi, in which the designed chemical composition was achieved, i.e. the partial replacement of nickel by manganese ensured the toughness at cryogenic temperatures. If these steels are supplementary alloyed, their strength properties may increase to the detriment of plasticity and toughness, although the cryogenic character is preserved

  2. Standard test methods for pitting and crevice corrosion resistance of stainless steels and related alloys by use of ferric Chloride solution

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 These test methods cover procedures for the determination of the resistance of stainless steels and related alloys to pitting and crevice corrosion (see Terminology G 15) when exposed to oxidizing chloride environments. Six procedures are described and identified as Methods A, B, C, D, E, and F. 1.1.1 Method A—Ferric chloride pitting test. 1.1.2 Method B—Ferric chloride crevice test. 1.1.3 Method C—Critical pitting temperature test for nickel-base and chromium-bearing alloys. 1.1.4 Method D—Critical crevice temperature test for nickel-base and chromium-bearing alloys. 1.1.5 Method E—Critical pitting temperature test for stainless steels. 1.1.6 Method F—Critical crevice temperature test for stainless steels. 1.2 Method A is designed to determine the relative pitting resistance of stainless steels and nickel-base, chromium-bearing alloys, whereas Method B can be used for determining both the pitting and crevice corrosion resistance of these alloys. Methods C, D, E and F allow for a rankin...

  3. Mechanical evaluation of quad-helix appliance made of low-nickel stainless steel wire.

    Science.gov (United States)

    dos Santos, Rogério Lacerda; Pithon, Matheus Melo

    2013-01-01

    The objective of this study was to test the hypothesis that there is no difference between stainless steel and low-nickel stainless steel wires as regards mechanical behavior. Force, resilience, and elastic modulus produced by Quad-helix appliances made of 0.032-inch and 0.036-inch wires were evaluated. Sixty Quad-helix appliances were made, thirty for each type of alloy, being fifteen for each wire thickness, 0.032-in and 0.036-in. All the archwires were submitted to mechanical compression test using an EMIC DL-10000 machine simulating activations of 4, 6, 9, and 12 mm. Analysis of variance (ANOVA) with multiple comparisons and Tukey's test were used (p nickel stainless steel alloy had force, resilience, and elastic modulus similar to those made of stainless steel alloy.

  4. Purity of food cooked in stainless steel utensils.

    Science.gov (United States)

    Flint, G N; Packirisamy, S

    1997-01-01

    An extensive programme of cooking operations, using household recipes, has shown that, apart from aberrant values associated with new pans on first use, the contribution made by 19% Cr/9% Ni stainless steel cooking utensils to chromium and nickel in the diet is negligible. New pans, if first used with acid fruits, showed a greater pick-up of chromium and nickel, ranging from approximately 1/20 to 1/3 and 1/20 to 1/2 of the normal daily intake of chromium and nickel respectively. This situation did not recur in subsequent usage, even after the pan had been cleaned by abrasion. A higher rate of chromium and nickel release in new pans on first use was observed on products from four manufactures and appears to be related to surface finish, since treatment of the surface of a new pan was partly, and in the case of electropolishing, wholly effective in eliminating their initial high release.

  5. Niobium stainless steel for implants

    International Nuclear Information System (INIS)

    Rollo, J.M.D.A.

    1983-01-01

    The materials that have often been used, during the last two or three decades, to carry out materials for implants are made according to the specifications: a)A.S.T.M. (F.55-76, F.56-76, F.138-76, F.139-76) stainless steel b)A.S.T.M. (F.75-76), cobalt-chromium-molybdenum alloys. c)A.S.T.M. (F.90-76), cobalt-chromium-tungsten-nickel alloys. d)A.S.T.M. (F.67-77), unalloyed titanium. e)A.S.T.M. (F.136-70), titanium alloys. It was the purpose of retaking them, toverify the niobium influence as alloy element in ANSI/ASTM F.55-76 classification stainless steels, usually for these materials elaboration. The problem by substituting molybdenum total or partially for niobium, by comparing the mechanical and corrosion properties, and biocompatibility is presented, by pointing out the variables of these substitutions, when we employ this new material to perform materials for implants. (Author) [pt

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

    Science.gov (United States)

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

    2001-12-05

    The impairment of skeletal muscle microcirculation by a biomaterial may have profound consequences. With moderately good physical and corrosion characteristics, implant-quality stainless steel is particularly popular in orthopedic surgery. However, due to the presence of a considerable amount of nickel in the alloy, concern has been voiced in respect to local tissue responses. More recently a stainless steel alloy with a significant reduction of nickel has become commercially available. We, therefore, studied in vivo nutritive perfusion and leukocytic response of striated muscle to this nickel-reduced alloy, and compared these results with those of the materials conventional stainless steel and titanium. Using the hamster dorsal skinfold chamber preparation and intravital microscopy, we could demonstrate that reduction of the nickel quantity in a stainless steel implant has a positive effect on local microvascular parameters. Although the implantation of a conventional stainless steel sample led to a distinct and persistent activation of leukocytes combined with disruption of the microvascular endothelial integrity, marked leukocyte extravasation, and considerable venular dilation, animals with a nickel-reduced stainless steel implant showed only a moderate increase of these parameters, with a clear tendency of recuperation. Titanium implants merely caused a transient increase of leukocyte-endothelial cell interaction within the first 120 min, and no significant change in macromolecular leakage, leukocyte extravasation, or venular diameter. Pending biomechanical and corrosion testing, nickel-reduced stainless steel may be a viable alternative to conventional implant-quality stainless steel for biomedical applications. Concerning tolerance by the local vascular system, titanium currently remains unsurpassed. Copyright 2001 John Wiley & Sons, Inc. J Biomed Mater Res 57: 404-412, 2001

  7. DT fusion neutron irradiation of BPNL niobium nickel and 316 stainless steel at 1750C

    International Nuclear Information System (INIS)

    MacLean, S.C.

    1977-01-01

    The DT fusion neutron irradiation at 175 0 C of 17 niobium wires, one niobium foil, 14 316 stainless steel wires, one 316 stainless steel foil, nine nickel wires, and two nickel foils from BPNL is described. The sample position, beam-on time, neutron dose record, and neutron fluence are given

  8. Deposition of DLC Film on Stainless Steel Substrates Coated by Nickel Using PECVD Method.

    Science.gov (United States)

    Khalaj, Zahra; Ghoranneviss, Mahmood; Vaghri, Elnaz; Saghaleini, Amir; Diudea, Mircea V

    2012-06-01

    Research on diamond-like carbon (DLC) films has been devoted to find both optimized conditions and characteristics of the deposited films on various substrates. In the present work, we investigate the quality of the DLC films grown on stainless steel substrates using different thickness of the nickel nanoparticle layers on the surface. Nickel nanoparticles were sputtered on the stainless steel substrates at 200 °C by a DC-sputtering system to make a good adherence between DLC coating and steel substrates. Atomic Force Microscopy was used to characterize the surface roughness and distribution function of the nickel nanoparticles on the substrate surface. Diamond like carbon films were deposited on stainless steel substrates coated by nickel using pure acetylene and C2H2/H2 with 15% flow ratio by DC-Plasma Enhanced Chemical Vapor Deposition (PECVD) systems. Microstructural analysis by Raman spectroscopy showed a low intensity ratio ID/IG for DLC films by increasing the Ni layer thickness on the stainless steel substrates. Fourier Transforms Infrared spectroscopy (FTIR) evidenced the peaks attributed to C-H bending and stretching vibration modes in the range of 1300-1700 cm-1 and 2700-3100 cm-1, respectively, in good agreement with the Raman spectroscopy and confirmed the DLC growth in all samples.

  9. Forgings made of austenitic chromium-nickel steels for the low temperature range

    International Nuclear Information System (INIS)

    Gruendler, O.; Schwarz, W.; Koren, M.

    1981-01-01

    The authors discuss the low temperature application of austenitic chromium-nickel steels for energy production and process techniques. Material requirements are presented, and the behaviour, mechanical and physical properties of such steels are discussed. The manufacture of forgings is considered and test results presented. (Auth.)

  10. Forgings made of austenitic chromium-nickel steels for the low temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Gruendler, O.; Schwarz, W.; Koren, M. (Vereinigte Edelstahlwerke A.G. (VEW), Kapfenberg (Austria))

    1981-09-01

    The authors discuss the low temperature application of austenitic chromium-nickel steels for energy production and process techniques. Material requirements are presented, and the behaviour, mechanical and physical properties of such steels are discussed. The manufacture of forgings is considered and test results presented.

  11. Corrosion of chromium, nickel, titanium and steels in solutions of sodium and ammonium thiosulfates

    International Nuclear Information System (INIS)

    Grebenshchikova, S.V.; Kochergin, V.P.; Doronina, I.V.

    1983-01-01

    Results of gravimetric determinatiion of average rate of chromium, nickel, titatnium and steels 12Kh18N10T and VSt.3 corrosion rate in solutions 50 mass.% (NH 4 ) 2 S 2 O 3 and Na 2 S 2 O 3 in the air and nitrogen atmosphere at 333 K have been generalized. Anodic polarization curves are recorded and stationary potentials of metals and steels under the conditions are measured. It is shown that in (NH 4 ) 2 S 2 O 3 solution the rate of metal and steels corrosion is higher than in Na 2 S 2 O 3 solution indepenent of the nature of gaseous medium contacting with solution. In the series Ni → VSt.3 → 12Kh18N10T → VT1 → chromium in (NH 4 ) 2 S 2 O 3 and Na 2 S 2 O 3 solutions at 333 K corrosion resistance increases. Chromium, titanium and chromium-nickel steel 12Kh18N10T possess a high corrosion resistance

  12. Welding of nickel free high nitrogen stainless steel: Microstructure and mechanical properties

    OpenAIRE

    Raffi Mohammed; G. Madhusudhan Reddy; K. Srinivasa Rao

    2017-01-01

    High nitrogen stainless steel (HNS) is a nickel free austenitic stainless steel that is used as a structural component in defence applications for manufacturing battle tanks as a replacement of the existing armour grade steel owing to its low cost, excellent mechanical properties and better corrosion resistance. Conventional fusion welding causes problems like nitrogen desorption, solidification cracking in weld zone, liquation cracking in heat affected zone, nitrogen induced porosity and poo...

  13. Comparison of radiographic density and compaction index of root canal obturation using nickel titanium or stainless-steel spreaders

    Directory of Open Access Journals (Sweden)

    M. Adel

    2016-08-01

    Full Text Available Background: Both nickel titanium and stainless-steel spreaders are available. The obvious advantage of nickel titanium spreader over stainless steel spreaders is greater penetration in curved canals. Objective: To compare the radiographic density and compaction index of root canal obturation using nickel-titanium or stainless-steel spreaders in curved canals. Methods: In this experimental study the primary weight of 30 acrylic blocks with 45o degrees of apical curvature were measured by a scale (W1. After canals were prepared by step back master apical up to file #30 all blocks were weighed again (W2 and randomly divided in two groups of 15each. All canals were obturated by Cold lateral compaction technique (with nickel-titanium in one group and stainless-steel finger spreaders in another group. After all blocks were reweighed (W3, compaction index (W3-W2/W1-W2 was calculated. One radiograph was taken for each sample. Apical density of the apical third of each canal was measured by digital transmission densitometer. Data were analyzed statistically using T-test. Findings: Mean compaction index for nickel-titanium group was 7.67±2.38 and for stainless-steel group was 9.14±4.06. There was no significant difference between two groups. Mean radiographic density of obturation was 2.05±0.14 in nickel-titanium group and was 2.07±0.21 in stainless-steel group. There was no significant difference between two groups. Conclusion: It is concluded that nickel-titanium spreaders are not superior than stainless-steel spreaders in obturating curved canal.

  14. CASTI handbook of stainless steels and nickel alloys. 2. ed.

    International Nuclear Information System (INIS)

    Lamb, S.

    2002-01-01

    This is the only up-to-date (2002) reference book that covers both stainless steels and nickel alloys. Written by 30 authors and peer reviewers with over 700 years of combined industrial experience, this CASTI handbook provides the latest stainless steels and nickel alloys information in a practical and comprehensive manner. For the project engineer, maintenance engineer or inspector, this book provides solutions to many of the corrosion problems encountered in aggressive environmental conditions. Some of the corrosive conditions covered are: stress corrosion cracking, reducing environments, halogenation, highly oxidizing environments, and high temperatures. Hundreds of different material applications and selections, throughout many industries, are referenced. It is an ideal reference source to assist in preventing or minimizing corrosion related problems, including those encountered during welding fabrication. This practical handbook also contains a handy 'Alloy Index' which lists each alloy by its ASTM Specification, UNS Number, common name, trade name and page number references. The second edition includes additional coverage of corrosion resistant alloys for downhole production tubing. The new material covers corrosion processes, corrosion rates, hydrogen sulfide environments, corrosion inhibitors, corrosion resistant alloys, the application of stainless steel in production conditions, and more

  15. Development of oxide dispersion strengthened 2205 duplex stainless steel composite

    Directory of Open Access Journals (Sweden)

    Oladayo OLANIRAN

    2015-05-01

    Full Text Available Composites of duplex stainless steel were produced by oxide dispersion strengthening with comparatively improved mechanical properties by hot press sintering of partially stabilized Zirconia (PSZ, 3% yttria, mole fraction dispersion in 2205 duplex stainless steels. Ceramic oxide was added as reinforcement, while chromium (Cr and Nickel (Ni were incorporated to maintain the austenitic/ferritic phase balance of the duplex stainless steel. The powders and sintered were characterized in detail using scanning electron microscopy (SEM and X-ray diffraction (XRD. The microstructural evolution and phase formation during oxide dispersion strengthening of duplex stainless steel composites were investigated. The influence of composition variation of the reinforcements on the microstructural and corrosion behaviour in simulated mine water of the composites were investigated. In this manuscript, it was established that composition has great influence on the structure/properties relationship of the composites developed.

  16. On superplasticity of corrosion resistant ferritic-austenitic chromium-nickel steels

    Energy Technology Data Exchange (ETDEWEB)

    Surovtsev, A P; Sukhanov, V E

    1988-01-01

    The deformability of corrosion resistant chromium-nickel ferritic austenitic steel type O8Kh22N6T under tension, upsetting and torsion in the 600-1200 deg C temperature range is studied. For the deformation rate of the order of 10/sup -3/ s/sup -1/ the effect of superelasticity reveals itself at 850 deg C in the process of ferrite dynamic polymerization, in the 925-950 deg C range, at initial stages of dynamic recrystallization - the dynamic polygonization controlled by chromium carbide dissolving in steel and maximum at 1050 deg C in the process of development of austenite dynamic recrystallization with grain refinement with F/A ratio equalling 1. After upsetting in the elasticity mode at 1050 deg C the impact strength of the above steel is maximum.

  17. Interfacial microstructure and mechanical properties of diffusion-bonded titanium-stainless steel joints using a nickel interlayer

    International Nuclear Information System (INIS)

    Kundu, S.; Chatterjee, S.

    2006-01-01

    Diffusion bonding was carried out between commercially pure titanium and 304 stainless steel using nickel interlayer in the temperature range of 800-950 deg. C for 3.6 ks under 3 MPa load in vacuum. The transition joints thus formed were characterized in optical and scanning electron microscopes. TiNi 3 , TiNi and Ti 2 Ni are formed at the nickel-titanium (Ni-Ti) interface; whereas, stainless steel-nickel (SS-Ni) interface is free from intermetallic compounds up to 900 deg. C processing temperatures. At 950 deg. C, Ni-Ti interface exhibits the presence of β-Ti discrete islands in the matrix of Ti 2 Ni and the phase mixture of λ + χ + α-Fe, λ + α-Fe, λ + FeTi + β-Ti and FeTi + β-Ti occurs at the stainless steel-nickel interface. Nickel is able to inhibit the diffusion of Ti to stainless steel side up to 900 deg. C temperature; however, becomes unable to restrict the migration of Ti to stainless steel at 950 deg. C. Bond strength was also evaluated and maximum tensile strength of ∼302 MPa and shear strength of ∼219 MPa were obtained for the diffusion couple processed at 900 deg. C temperature due to better contact of the mating surfaces and failure takes place at the Ni-Ti interface. At higher joining temperature, the formation of Fe-Ti bases intermetallics reduces the bond strength and failure occurs at the SS-Ni interface

  18. Pitting corrosion resistant austenite stainless steel

    Science.gov (United States)

    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.

  19. Grain boundary chromium concentration effects on the IGSCC and IASCC of austenitic stainless steels

    International Nuclear Information System (INIS)

    Bruemmer, S.M.; Arey, B.W.; Charlot, L.A.

    1993-08-01

    Comparisons are made between grain boundary composition and intergranular stress corrosion cracking (IGSCC) of 304 and 309 austenitic stainless steels in high-temperature water environments. Chromium depletion had the dominant effect on cracking resistance with the extent of IG cracking controlled by the interfacial chromium concentration. The minimum chromium concentration required to promote cracking was a function of the applied strain rate during slow-strain-rate tensile tests in 288 C air-saturated water. Depletion from bulk levels of 18 wt% to ∼13.5 wt% Cr at grain boundaries prompted 100% IG cracking at a strain rate of 1 x 10 -6 s -1 , while embrittlement was observed with only a slight depletion to ∼17 wt% at 2 x 10 -7 s -1 . Insights into critical interfacial compositions promoting IGSCC are discussed in reference to cracking of irradiated stainless steel nuclear reactor core components

  20. High temperature dissolution of chromium substituted nickel ferrite in nitrilotriacetic acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Sathyaseelan, V.S.; Chandramohan, P.; Velmurugan, S., E-mail: svelu@igcar.gov.in

    2016-12-01

    High temperature (HT) dissolution of chromium substituted nickel ferrite was carried out with relevance to the decontamination of nuclear reactors by way of chemical dissolution of contaminated corrosion product oxides present on stainless steel coolant circuit surfaces. Chromium substituted nickel ferrites of composition, NiFe{sub (2−x)}Cr{sub x}O{sub 4} (x ≤ 1), was synthetically prepared and characterized. HT dissolution of these oxides was carried out in nitrilotriacetic acid medium at 160 °C. Dissolution was remarkably increased at 160 °C when compared to at 85 °C in a reducing decontamination formulation. Complete dissolution could be achieved for the oxides with chromium content 0 and 0.2. Increasing the chromium content brought about a marked reduction in the dissolution rate. About 40 fold decrease in rate of dissolution was observed when chromium was increased from 0 to 1. The rate of dissolution was not very significantly reduced in the presence of N{sub 2}H{sub 4}. Dissolution of oxide was found to be stoichiometric. - Highlights: • Dissolution of NiFe{sub (2−x)}Cr{sub x}O{sub 4} was remarkably increased at 160 °C in NTA medium. • The dissolution was significantly decreasing with the increase in Cr content in the oxide. • Dissolution rate is dependent on the lability of metal-oxo bonds. • The rate of dissolution was not significantly reduced in the presence of N{sub 2}H{sub 4.} • NTA at high temperature is effective for decontamination of stainless steel surfaces.

  1. Biodegradation of nickel and chromium from space maintainers: An in vitro study

    Directory of Open Access Journals (Sweden)

    Bhaskar V

    2010-03-01

    Full Text Available Band materials are often used in the practice of pediatric dentistry. Nickel and Chromium are the main ingredients of these materials. The potential health hazards of nickel and chromium and their compounds have been the focus of attention for more than 100 years. It has established that these metals could cause hypersensitivity. The study was undertaken to analyze in vitro biodegradation of space maintainers made out of stainless steel band materials from manufacturers Dentaurum and Unitek. The leaching effect simulating the use of one, two, three, and four space maintainers in clinical practice was studied by keeping the respective number of space maintainers in the artificial saliva incubating at 37°C and analyzing for nickel and chromium release after 1,7,14,21 and 28 days using atomic absorption spectrophotometer. Results showed that there was measurable release of both nickel and chromium which reached maximum level at the end of 7 days which was statistically significant (P < 0.05 and was very much below the dietary average intake even for four bands used and was not capable of causing any toxicity.

  2. Characterization and Evaluation of Aged Chromium Nickel Niobium Stainless Steels

    Science.gov (United States)

    Dewar, Matthew

    20Cr-32Ni-1Nb stainless steel alloys are commonly used in hydrogen reformer manifolds for transporting hot hydrogen by-products at 750-950°C. After long periods of exposure, embrittling secondary carbides and intermetallic phases can precipitate at the grain boundaries which can drastically reduce the ductility, and the repair weldability of the alloy. The intermetallic silicide, G-phase, is commonly observed in 20Cr-32Ni-1Nb stainless steels, and is prone to liquation cracking during welding operations. G-phase is deleterious to the material, where a high degree of G-phase coarsening will render the material unweldable. The present work will investigate various methods in mitigating G-phase precipitation. Variations in casting methods, wall thickness, homogenization treatments, and alloy chemistry will be examined by evaluating their microstructure after periodically aging the samples. Thermodynamic equilibrium modeling using computational thermodynamic tools will be used to optimize the 20Cr-32Ni-1Nb chemistry following ASTM specifications.

  3. Intragranular Chromium Nitride Precipitates in Duplex and Superduplex Stainless Steel

    OpenAIRE

    Iversen, Torunn Hjulstad

    2012-01-01

    Intragranular chromium nitrides is a phenomenon with detrimental effects on material properties in superduplex stainless steels which have not received much attention. Precipitation of nitrides occurs when the ferritic phase becomes supersaturated with nitrogen and there is insufficient time during cooling for diffusion of nitrogen into austenite. Heat treatment was carried out at between 1060◦C and 1160◦C to study the materials susceptibility to nitride precipitation with...

  4. The Effects of Alloy Chemistry on Localized Corrosion of Austenitic Stainless Steels

    Science.gov (United States)

    Sapiro, David O.

    This study investigated localized corrosion behavior of austenitic stainless steels under stressed and unstressed conditions, as well as corrosion of metallic thin films. While austenitic stainless steels are widely used in corrosive environments, they are vulnerable to pitting and stress corrosion cracking (SCC), particularly in chloride-containing environments. The corrosion resistance of austenitic stainless steels is closely tied to the alloying elements chromium, nickel, and molybdenum. Polarization curves were measured for five commercially available austenitic stainless steels of varying chromium, nickel, and molybdenum content in 3.5 wt.% and 25 wt.% NaCl solutions. The alloys were also tested in tension at slow strain rates in air and in a chloride environment under different polarization conditions to explore the relationship between the extent of pitting corrosion and SCC over a range of alloy content and environment. The influence of alloy composition on corrosion resistance was found to be consistent with the pitting resistance equivalent number (PREN) under some conditions, but there were also conditions under which the model did not hold for certain commercial alloy compositions. Monotonic loading was used to generate SCC in in 300 series stainless steels, and it was possible to control the failure mode through adjusting environmental and polarization conditions. Metallic thin film systems of thickness 10-200 nm are being investigated for use as corrosion sensors and protective coatings, however the corrosion properties of ferrous thin films have not been widely studied. The effects of film thickness and substrate conductivity were examined using potentiodynamic polarization and scanning vibrating electrode technique (SVET) on iron thin films. Thicker films undergo more corrosion than thinner films in the same environment, though the corrosion mechanism is the same. Conductive substrates encourage general corrosion, similar to that of bulk iron

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

    Science.gov (United States)

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

    2018-01-15

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

  6. Determination of the chromium concentration of phase decomposition products in an aged duplex stainless steel

    International Nuclear Information System (INIS)

    Kuwano, Hisashi; Imamasu, Hisanao

    2006-01-01

    A commercial duplex stainless steel has been aged at 673 K for up to 55,000 h. The aging results in the phase decomposition of the ferrite in duplex stainless steel. The end products of the phase decomposition are a Fe-rich and a Cr-rich phase. The chromium concentration of these phases is determined by measuring the hyperfine magnetic field and the isomer shift using Moessbauer effect. The experimental results are compared with a phase diagram calculated for Fe-Cr-Ni ternary system at 673 K.

  7. Standard practice for determining the susceptibility of stainless steels and related Nickel-Chromium-Iron Alloys to stress-corrosion cracking in polythionic acids

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice covers procedures for preparing and conducting the polythionic acid test at room temperature, 22 to 25°C (72 to 77°F), to determine the relative susceptibility of stainless steels or other related materials (nickel-chromiumiron alloys) to intergranular stress corrosion cracking. 1.2 This practice can be used to evaluate stainless steels or other materials in the “as received” condition or after being subjected to high-temperature service, 482 to 815°C (900 to 1500°F), for prolonged periods of time. 1.3 This practice can be applied to wrought products, castings, and weld metal of stainless steels or other related materials to be used in environments containing sulfur or sulfides. Other materials capable of being sensitized can also be tested in accordance with this test. 1.4 This practice may be used with a variety of stress corrosion test specimens, surface finishes, and methods of applying stress. 1.5 This standard does not purport to address all of the safety concerns, if any, ...

  8. Weldability of neutron-irradiated stainless steel and nickel-base alloy

    International Nuclear Information System (INIS)

    Koyabu, Ken; Asano, Kyoichi; Takahashi, Hidenori; Sakamoto, Hiroshi; Kawano, Shohei; Nakamura, Tomomi; Hashimoto, Tsuneyuki; Koshiishi, Masato; Kato, Takahiko; Katsura, Ryoei; Nishimura, Seiji

    2000-01-01

    Degradation of of weldability caused by helium, which is generated by nuclear transmutation irradiated material, is an important issue to be addressed in planning of proactive maintenance of light water reactor core internal components. In this work, the weldability of neutron.irradiated stainless steel and nickel-base alloy, which are major constituting materials for components, was practically evaluated. The weldability was first examined by TIG welding in relation to the weld heat input and helium content using various specimens (made of SUS304 and SUS316L) sampled from reactor internal components. The specimens were neutron irradiated in a boiling water reactor to fluences from 4 x 10 24 to 1.4 x 10 26 n/ m 2 (E> l MeV ), and resulting helium generation ranged from 0.1 to 103 appm. The weld defects were characterized by dye penetrant test and cross-sectional metallography. The weldability of neutron-irradiated stainless steel was shown to be better at lower weld heat input and lower helium content. To evaluate mechanical properties of welded joints, thick plates (20 mm) specimens of SUS304 and Alloy 600 were prepared and irradiated in Japan Material Test Reactor (JMTR). The helium content of the specimens was controlled to range from 0.11 to 1.34 appm selected to determine threshold helium content to weld successfully. The welded joints had multiple passes by TIG welding process at 10 and 20 kJ/cm heat input. The welded joints of thick plate were characterized by dye penetrant test, cross-sectional metallography, tensile test, side bend test and root bend test. It was shown that irradiated stainless steel containing below 0.14 appm of helium could be welded with conventional TIG welding process (heat input below 20 kJ/cm). Nickel-base alloy, which contained as much helium as stainless steel could be welded successfully, could also be welded with conventional TIG welding process, These results served as basis to evaluate the applicability of repair welding to

  9. Effect of temperature and aluminium additions on the mechanical properties of the 13% chromium ferrite stainless steels

    International Nuclear Information System (INIS)

    Martins, S.

    1975-01-01

    The potential interest of the ferritic stainless steels as component materials for nuclear power reactors led to investigate how aluminium influences the mechanical properties of 13% chromium ferritic stainless steels between room temperature and about 700 0 C. Nominal 13% chromium and 0.04 to 0.08% carbon ferritic stainless steels containing 0, 0.13, 2.19 and 4.15% aluminium, respectively, were obtained by vacuum remelting of a commercial martensitic-ferritic stainless steel and suitable additions of aluminium. After successive rolling operations and recrystallizations performed in order to obtain final 0.5 mm thick sheets with similar average grain sizes the specimens of the above mentioned steels were tested in a tensile test Instron machine, with a constant strain rate (approximately equal to 1.6 x 10 -3 min -1 ), at room temperature, 140, 265, 415, 565 and 715 0 C. The results obtained show that strengthening by aluminium is strongly temperature dependent. At 265 0 C all the steels presentes serrated plastic deformation (Portevin-Le Chatelier effect), which is attributed to interactions of the interstitial and substitutional solute atoms with dislocations in the body centered cubic structure. Flow stress drops were still observed at 465 0 C, although the tests performed at 565 and 715 0 C showed work-softening of the materials and total absence of serrations. Stress relaxation tests at room temperature yielded values of the apparent activation volumes, which are scattered between about 100 and 130 b 3 (b-Burgers vector), being almost constant with stress, strain and aluminium content. Therefore, although aluminium appreciably strengthens the 13% chromium steel, the behaviour summarized suggests that the mechanism controlling plastic deformation at room temperature is the same for all the tested steels, the values of the apparent activitation volumes being probably determined by the interstitial content. Stress relaxation tests at 20, 75, 140 and 265 0 C for

  10. Effect of nitrate on corrosion of austenitic stainless steel in boiling nitric acid solution containing chromium ions

    International Nuclear Information System (INIS)

    Hasegawa, Satoshi; Kim, Seong-Yun; Ebina, Tetsunari; Ito, Tatsuya; Nagano, Nobumichi; Hitomi, Keitaro; Ishii, Keizo; Tokuda, Haruaki

    2016-01-01

    The oxidation behavior of chromium and the corrosion behavior of austenitic stainless steel in boiling nitric acid solution containing highly concentrated nitrates were investigated using UV-visible spectroscopic measurements, Raman spectral measurements, immersion tests, and potentiodynamic polarization measurements. The oxidation rate measurement of chromium from Cr(III) to Cr(VI) was performed by 1 M boiling nitric acid solution containing each highly concentrated nitrates: Al(NO_3)_3, Nd(NO_3)_3, Ca(NO_3)_2, Mg(NO_3)_2, and NaNO_3 as a simulant of uranium nitrate in uranium concentrator in reprocessing plants. As a result, the rate of chromium oxidation was different depending on the added nitrates even at the same nitric acid concentration. In addition, the oxidation rate of chromium was increased with increasing the calculated partial pressure of nitric acid in consideration of the hydration of cation of nitrates. Furthermore, the corrosion rate of type 310 stainless steel was accelerated by the solution having a high chromium oxidation rate containing nitrates. These results indicated that the acceleration of the corrosion rate in the solutions depending on the oxidation rate of chromium, and the rate is affected by the salt-effect of nitrates. (author)

  11. Monitoring of occupational exposure in manufacturing of stainless steel constructions. Part I: Chromium, iron, manganese, molybdenum, nickel and vanadium in the workplace air of stainless steel welders

    International Nuclear Information System (INIS)

    Kucera, J.; Hnatowicz, V.; Bencko, V.; Papayova, A.; Saligova, D.; Tejral, J.; Borska, L.

    2000-01-01

    Exposure to workplace airborne pollutants was examined in a group of 20 workers dealing mainly with welding, polishing, drilling and assembling of stainless steel constructions. Monitoring of airborne particulate matter (ARM) was performed using both personal and stationary samplers. For the personal full-shift monitoring, a SKC 224 PCRX-4 constant flow rate pump was used which was connected to a sampling head with mixed cellulose matched-weight filters having a diameter of 32 mm and a 0.8 μm pore size. The constant flow rate amounted to 2 L min -1 . For the stationary sampling, the ''Gent'' stacked filter unit PM10 sampler was used, operating at a flow rate of 16 L min -1 . It collects particles having an equivalent aerodynamic diameter (EAD) of less than 10,um in the separate ''coarse'' (2-10 μm EAD) and ''fine'' (< 2 μm EAD) size fractions on two sequential polycarbonate (Costar, Nuclepore) filters with a 47 mm diameter. The filters of both types were analyzed by instrumental neutron activation analysis (INAA). Of the elements determined, results for chromium, iron, manganese, molybdenum, nickel and vanadium are presented. Procedures for quality assurance of both sampling and analytical stages are described. Sampling of biological material for elemental analysis (hair, nails, urine and blood and/or serum) of exposed and control persons in contamination-free conditions was also performed. In addition, saliva samples were collected for studying immunological and genotoxicity aspects of occupational exposure. (author)

  12. Estimation of changes in nickel and chromium content in nickel-titanium and stainless steel orthodontic wires used during orthodontic treatment: An analytical and scanning electron microscopic study

    Directory of Open Access Journals (Sweden)

    Vandana Kararia

    2015-01-01

    Full Text Available Introduction: The biocompatibility of orthodontic dental alloys has been investigated over the past 20 years, but the results have been inconclusive. The study compares standard 3 M Unitek nickel-titanium (NiTi and stainless steel archwires with locally available JJ orthodontics wires. Scanning electron microscope (SEM study of surface changes and complexometric titration to study compositional change was performed. Materials and Methods: Ten archwires each of group 1-3 M 0.016" NiTi, group 2-JJ 0.016" NiTi, group 3-3 M 0.019" FNx010.025" SS and group 4-JJ SS contributed a 10 mm piece of wire for analysis prior to insertion in the patient and 6 weeks post insertion. SEM images were recorded at Χ2000, Χ4000 and Χ6000 magnification. The same samples were subjected to complexiometric titration using ethylenediaminetetraacetic acid to gauge the actual change in the composition. Observations and Results: The SEM images of all the archwires showed marked changes with deep scratches and grooves and dark pitting corrosion areas post intraoral use. 3M wires showed an uniform criss-cross pattern in as received wires indicating a coating which was absent after intraoral use. There was a significant release of Nickel and Chromium from both group 3 and 4. Group 2 wires released ions significantly more than group 1 (P = 0.0. Conclusion: Extensive and stringent trials are required before certifying any product to be used in Orthodontics.

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

    Science.gov (United States)

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

    2017-03-01

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

  14. Simulation of radiation induced segregation and PWSCC susceptibility for austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto Koji; Yonezawa, Toshio; Iwamura, Toshihiko [Mitsubishi Heavy Industries Ltd., Takasago, Hyogo (Japan). Takasago R and D Center; Ajiki, Kazuhide [Mitsubishi Heavy Industries Ltd., Kobe (Japan). Kobe Shipyard and Machinery Works; Urata, Sigeru [General Office of Nuclear and Fossil Power Production, Kansai Electric Power Co., Inc., Osaka (Japan)

    2000-08-01

    Recently, irradiation assisted stress corrosion cracking (IASCC) of austenitic stainless steels for core internal components materials become a subject of discussion in light water reactors (LWRs). IASCC has not been found in Pressurized Water Reactors (PWRs). However, the authors have investigated on the possibility of IASCC of austenitic stainless steels for core internal materials so as to be able to estimate the degradation of PWR plants up to the end of their lifetime. In this study, in order to verify the hypothetical that the IASCC in PWRs shall be caused by the primary water stress corrosion cracking (PWSCC) as a result of radiation induced segregation (RIS) at grain boundaries, the authors simulated RIS at grain boundaries of austenitic stainless steels based on previous study and estimated RIS tendency after long time operation. And the authors melted the test alloys whose bulk compositions simulated the grain boundary compositions of irradiated austenitic stainless steels and made clear chromium-nickel-silicon compositions for PWSCC susceptibility area in austenitic alloys by slow strain rate tensile (SSRT) test. (author)

  15. Simulation of radiation induced segregation and PWSCC susceptibility for austenitic stainless steels

    International Nuclear Information System (INIS)

    Fujimoto Koji; Yonezawa, Toshio; Iwamura, Toshihiko

    2000-01-01

    Recently, irradiation assisted stress corrosion cracking (IASCC) of austenitic stainless steels for core internal components materials become a subject of discussion in light water reactors (LWRs). IASCC has not been found in Pressurized Water Reactors (PWRs). However, the authors have investigated on the possibility of IASCC of austenitic stainless steels for core internal materials so as to be able to estimate the degradation of PWR plants up to the end of their lifetime. In this study, in order to verify the hypothetical that the IASCC in PWRs shall be caused by the primary water stress corrosion cracking (PWSCC) as a result of radiation induced segregation (RIS) at grain boundaries, the authors simulated RIS at grain boundaries of austenitic stainless steels based on previous study and estimated RIS tendency after long time operation. And the authors melted the test alloys whose bulk compositions simulated the grain boundary compositions of irradiated austenitic stainless steels and made clear chromium-nickel-silicon compositions for PWSCC susceptibility area in austenitic alloys by slow strain rate tensile (SSRT) test. (author)

  16. Discussion on two special stainless steels used in nuclear fuel processing plants

    International Nuclear Information System (INIS)

    Desestret, A.; Ferriol, J.; Vallier, G.

    1977-01-01

    Nuclear fuel treatment may entail difficult corrosion problems for the metallurgist. A first case occurs when the nitric solution is concentrated (60 to 70% of HNO 3 ) at temperatures of 130 0 C. This is solved by use of a steel having a very high chromium content (25%), a high nickel content (20%), and a very low carbon content, which is now readily produced on an industrial scale. A second case happens when nitric solutions are made highly agressive, even when diluted at medium temperatures, by highly oxidising ions such as chromate or ceric ions. The stainless steel is then placed in transpassive conditions and subject to very rapid intergranular attack, even when free from precipitated chromium carbides. A steel of the Cr 17 / Ni 14 / Si 4 / C [fr

  17. Plating on stainless steel alloys

    International Nuclear Information System (INIS)

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

    1981-01-01

    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

  18. Corrosion behavior of 2205 duplex stainless steel.

    Science.gov (United States)

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

    1997-07-01

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

  19. Penentuan konsentrasi stainless steel 316L dan kobalt kromium remanium GM-800 pada uji GPMT

    Directory of Open Access Journals (Sweden)

    Ikmal Hafizi

    2016-12-01

    Full Text Available Concentration determination of stainless steel 316L and cobalt chromium remanium GM - 800 on GPMT test. Dentistry had used metals such as cobalt chromium and stainless steel in maxillofacial surgery, cardiovascular, and as a dental material. 316L stainless steel is austenistic stainless steel which has low carbon composition to improve the corrosion resistance as well as the content of molybdenum in the material. Cobalt chromium (CoCr is a cobaltbased alloy with a mixture of chromium. Density of a metal cobalt chromium alloy is about 8-9 g/cm3 that caused metal interference relatively mild. Remanium GM-800 is one type of a cobalt chromium alloy with the advantages of having high resistance to fracture and high modulus of elasticity. This study aims to determine the exact concentration used in 316L stainless steel and cobalt chromium GM-800 as the GPMT test material. Subjects were cobalt chromium Remanium GM-800 and 316L stainless steel concentration of 5%, 10%, 20%, 40% and 80%. Patch containing stainless steel or cobalt chromium paste was af xed for 24 hours each on three experimental animals, then the erythema and edema were observed using the Magnusson and Kligman scale. In the study, concentration of 5% is the concentration recommended for stainless steel 316L and cobalt chromium GM-800 as material in challenge phase GPMT test, while the concentration of 40% is the concentration recommended for stainless steel 316L and cobalt chromium GM-800 in the induction phase. ABSTRAK Dunia kedokteran gigi banyak menggunakan logam pada pembedahan maxillofacial, cardiovascular, dan sebagai material dental. Logam yang banyak digunakan antara lain adalah kobalt kromium dan stainless steel. Stainless steel 316L merupakan austenistic stainless steel yang memiliki komposisi karbon rendah sehingga dapat meningkatkan ketahanan terhadap korosi sama halnya dengan kandungan molybdenum pada material tersebut. Kobalt kromium (CoCr adalah cobalt-based alloy dengan

  20. Alloying effect on martensite transformation in stainless steels

    International Nuclear Information System (INIS)

    Gulyaev, A.P.; Shlyamnev, A.P.; Sorokina, N.A.

    1975-01-01

    The effect of cobalt, nickel, molybdenum on the martensite transformation kinetics in stainless steels containing 9 to 13% Cr has been studied. Cobalt in Fe-Cr base alloys decreases the temperature of the Msub(in) and Msub(fin) points without a considerable decrease of the martensite phase amount after the transformation. Nickel reduces the martensite transformation temperature range, the nickel effect being enhanced in the presence of cobalt, which is characterized by a change of the linear dependence Msub(in)=f(%Ni) for a quadratic one. Molybdenum decreases the temperature of the Msub(in) and Msub(fin) points intensively, thus, substantially increasing the residual austenite amount. In the steels investigated Ni and Co decrease, whereas Mo increases, to some extent, the temperature of the reverse a-γ-transformation. The reduction of chromium content from 13 to 9% stimulates the martensite transformation initiation, that is why, in alloys containing 9% Cr, the increase in the contents of Ni, Co., Mo with the martensite structure maintained is possible. A further alloying of steel containing 13% Cr with these elements is rather limited due to the inhibition of the martensite transformation

  1. Comparison of high temperature wear behaviour of plasma sprayed WC–Co coated and hard chromium plated AISI 304 austenitic stainless steel

    International Nuclear Information System (INIS)

    Balamurugan, G.M.; Duraiselvam, Muthukannan; Anandakrishnan, V.

    2012-01-01

    Highlights: ► WC–12wt.%Co powders were deposited to a thickness of 300 μm on to steel substrates. ► The micro hardness of the above coatings was lower than that of chromium plating. ► Wear resistance of chromium coating was increased up to five times of AISI 304 austenitic stainless steel. ► Wear resistance of chromium coat higher than plasma coat at different temperatures. -- Abstract: The wear behaviour of plasma sprayed coating and hard chrome plating on AISI 304 austenitic stainless steel substrate is experimentally investigated in unlubricated conditions. Experiments were conducted at different temperatures (room temp, 100 °C, 200 °C and 300 °C) with 50 N load and 1 m/s sliding velocity. Wear tests were carried out by dry sliding contact of EN-24 medium carbon steel pin as counterpart on a pin-on-disc wear testing machine. In both coatings, specimens were characterised by hardness, microstructure, coating density and sliding wear resistance. Wear studies showed that the hard chromium coating exhibited improved tribological performance than that of the plasma sprayed WC–Co coating. X-ray diffraction analysis (XRD) of the coatings showed that the better wear resistance at high temperature has been attributed to the formation of a protective oxide layer at the surface during sliding. The wear mechanisms were investigated through scanning electron microscopy (SEM) and XRD. It was observed that the chromium coating provided higher hardness, good adhesion with the substrate and nearly five times the wear resistance than that obtained by uncoated AISI 304 austenitic stainless steel.

  2. Experience in melting of high-quality chromium-nickel-molybdenum steel in oxygen converter

    Energy Technology Data Exchange (ETDEWEB)

    Kosoi, L F; Yaburov, S I; Shul' kin, M L; Vedernikov, G G; Bragin, E D; Filork' yan, B K

    1978-10-01

    Technology of melting high-quality medium-carbon constructional chromium-nickel-molybdenum steel has been developed and tested in 130-t converters. The technology envisages metal refinement in a casting laddle using synthetic lime-aluminous slag and argon blowing, as well as liquid ferroallys (master alloys) for steel deoxidation and alloying. Due to a smaller content of sulfur, phosphorus, arsenic and sulphide inclusions, and to a smaller grain size (N 11-12), the steel, produced according to this technology possesses higher plastic properties and impact strength than conventional open-hearth furnace metal after heat treatment for the same strength.

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

    Science.gov (United States)

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

    2016-09-01

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

  4. Effects of solution temperature on localized corrosion of high nickel content stainless steels and nickel in chromated LiBr solution

    International Nuclear Information System (INIS)

    Munoz, A. Igual; Anton, J. Garcia; Guinon, J.L.; Perez Herranz, V.

    2006-01-01

    The potentiodynamic technique has been used to study the general and localized corrosion resistance of high-alloyed stainless steels (UNS N02031 and UNS R20033) and nickel (UNS N02205) at different temperatures (from 25 deg. C to 80 deg. C) in a heavy brine Lithium Bromide solution. The engineering question of concern is the compatibility of the LiBr fluid with the structural materials of refrigeration systems which use absorption technology. The results of potentiodynamic polarization studies indicate excellent corrosion resistance for stainless steels in LiBr solution at room temperature and no big differences at temperatures above 50 deg. C. In the temperature range of 25-80 deg. C, a linear relationship exists between logarithmic of corrosion rate and reciprocal of absolute temperature (Arrhenius plot). The linear plots showed that the mechanism of the corresponding passivation process is the same for the three investigated alloys, essentially due to the presence of nickel. Tests indicated that stainless steels UNS N02031 and UNS R20033 were the most suitable for use to be used in the construction of absorption units for refrigeration purposes

  5. Effects of Aging and W Addition on the Microstructure of Fe-Cr-Mn-N Stainless Steels

    International Nuclear Information System (INIS)

    Jeon, Yu Taek; Joo, Uk Hyon; Park, Yong Soo; Kim, Young Sik

    2000-01-01

    The effects of aging treatment on the precipitation behaviors of Fe-Cr-Mn-N stainless steels were studied using a transmission electron microscopy, scanning electron microscopy, optical microscopy and XRD. In the austenitic stainless steel having a single phase. M23C6 carbides were first precipitated in the grain boundary by aging and then grew from grain boundary into grain with aging time. Carbides showed lamellar structures. It was shown from the analysis of spot patterns that carbides had a coherent relation with matrix and their lattice parameter was roughly three times that of austenite. During initial stages of M23C6 carbide precipitation, the iron content was quite high. With increasing aging time, the chromium content was increased. As the tungsten was added to improve the corrosion resistance of the Fe-Cr-Mn-N stainless steels, ferrite phase was formed. This ferrite phase was decomposed to chi(χ) phase and secondary austenite. Chi phase was mainly enriched with tungsten, chromium and tungsten were depleted in the secondary austenite due to the formation of chi phase. M23C6 carbides were also formed in the grain boundary. Nickel stabilized the austenite phase and decreased the ferrite volume fraction. But nickel content was not sufficient to suppress the formation of ferrite, and precipitation behaviors were not changed

  6. Effects of aging treatment and W addition on the microstructure of Fe-Cr-Mn stainless steels

    International Nuclear Information System (INIS)

    Jeoun, Y. T.; Zoo, W. H.; Kim, Y. S.; Park, Y. S.

    1999-01-01

    The effects of aging treatment on the precipitaion behaviors of Fe-Cr-Mn-W stainless steels were studied using a transmission electron microscopy, scanning electron microscopy, optical microscopy and XRD. In the austenitic stainless steel showing a single phase, M 23 C 6 carbides were first precipitated in the grain boundary by aging and then grew from grain boundary into grain with aging time. Carbides showed lamellar structures. It was shown from the analysis of spot patterns that carbides had a coherent relation with matrix and their lattice parameter was roughly three times that of austenite. During initial stages of M 23 C 6 carbide precipitaion, the iron content was quite high. With increasing aging time, the chromium content increased. As the tungsten was added to improve the corrosion resistance of the Fe-Cr-Mn stainless steels, ferrite phase was formed. These ferrite phase was decomposed to chi(χ) phase and secondary austenite. Chi phase was mainly enriched with tungsten, chromium and tungsten were depleted in the secondary austenite due to the formation of chi phase. M 23 C 6 carbides were also formed in the grain boundary. Nickel stabilized the austenite phase and decreased the ferrite volume fraction. But nickel content was not sufficient to suppress the formation of ferrite, and precipitaion behaviors were not changed

  7. Effects of nitrogen on corrosion of stainless steels in a liquid sodium environment

    International Nuclear Information System (INIS)

    Suzuki, Tadashi; Mutoh, Isao

    1990-01-01

    The corrosion of ferritic stainless steels using sodium at 650degC in a maximum isothermal region contained in a non-isothermal sodium loop constructed of a Type 316 stainless steel has been examined. Also, previous results on corrosion of austenitic stainless steels in sodium at 700degC in the same loop have been reproduced. The selective dissolution and absorption of nickel, the selective dissolution of chromium, and the resultant increase in iron in the surface of stainless steels in the loop mainly determine the corrosion loss of the stainless steel specimens. The austenitic steels hardly decarburize, but denitride. The ferritic steels decarburize and denitride and the denitriding is more remarkable than the decarburizing. The vanadium and niobium, carbide and nitride formers, in the ferritic steels inhibit the decarburizing to some extent, but barely inhibit the denitriding. The nitrogen in the steels rapidly diffuses to the grain boundaries, and rapidly dissolves into sodium, which will lower surface energy of the steels to enhance the dissolution of other elements. The dissolved N in sodium would then be transported to the free surface of the sodium adjacent to the argon cover gas of sodium and easily be released into the cover gas. This mechanism would cause the rapid dissolution of nitrogen into sodium and the enhancement of the corrosion rate of the steels containing nitrogen. (orig.)

  8. Investigation of irradiation induced inter-granular stress corrosion cracking susceptibility on austenitic stainless steels for PWR by simulated radiation induced segregation materials

    Energy Technology Data Exchange (ETDEWEB)

    Yonezawa, Toshio; Fujimoto, Koji; Kanasaki, Hiroshi; Iwamura, Toshihiko [Mitsubishi Heavy Industries Ltd., Takasago R and D Center, Takasago, Hyogo (Japan); Nakada, Shizuo; Ajiki, Kazuhide [Mitsubishi Heavy Industries Ltd., Kobe Shipyard and Machinery Works, Kobe, Hyogo (Japan); Urata, Sigeru [General Office of Nuclear and Fossil Power Production, Kansai Electric Power Co., Inc., Osaka (Japan)

    2000-07-01

    An Irradiation Assisted Stress Corrosion Cracking (IASCC) has not been found in Pressurized Water Reactors (PWRs). However, the authors have investigated on the possibility of IASCC so as to be able to estimate the degradation of PWR plants up to the end of their lifetime. In this study, the authors melted the test alloys whose bulk compositions simulated the grain boundary compositions of irradiated Type 304 and Type 316 CW stainless steels. Low chromium, high nickel and silicon (12%Cr-28%Ni-3%Si) steel showed high susceptibility to PWSCC (Primary Water Stress Corrosion Cracking) by SSRT (Slow Strain Rate Tensile) test in simulated PWR primary water. PWSCC susceptibility of the test steels increases with a decrease of chromium content and a increase of nickel and silicon contents. The aged test steel included coherent M{sub 23}C{sub 6} carbides with matrices at the grain boundaries showed low PWSCC susceptibility. This tendency is in very good agreement with that of the PWSCC susceptibility of nickel based alloys X-750 and 690. From these results, if there is the possibility of IASCC for austenitic stainless steels in PWRs, in the future, the IASCC shall be caused by the PWSCC as a result of irradiation induced grain boundary segregation. (author)

  9. Roentgenoelectronic investigation into oxidation of iron-chromium and iron-chromium-nickel alloys

    International Nuclear Information System (INIS)

    Akimov, A.G.; Rozenfel'd, I.L.; Kazanskij, L.P.; Machavariani, G.V.

    1978-01-01

    Kinetics of iron-chromium and iron-chromium-nickel alloy oxidation (of the Kh13 and Kh18N10T steels) in oxygen was investigated using X-ray electron spectroscopy. It was found that according to X-ray electron spectra chromium oxidation kinetics in the iron-chromium alloy differs significantly from oxidation kinetics of chromium pattern. Layer by layer X-ray electron analysis showed that chromium is subjected to a deeper oxidation as compared to iron, and accordingly, Cr 2 O 3 layer with pure iron impregnations is placed between the layer of mixed oxide (Fe 3 O 4 +Cr 2 O 3 ) and metal. A model of the iron-chromium alloy surface is suggested. The mixed oxide composition on the steel surface is presented as spinel Fesub(2+x)Crsub(1-x)Osub(y)

  10. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    KAUST Repository

    Serdar, Marijana

    2015-05-01

    © 2015 Elsevier Ltd All rights reserved. The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide-hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel.

  11. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    KAUST Repository

    Serdar, Marijana; Meral, Cagla; Kunz, Martin; Bjegovic, Dubravka; Wenk, Hans-Rudolf; Monteiro, Paulo J.M.

    2015-01-01

    © 2015 Elsevier Ltd All rights reserved. The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide-hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel.

  12. Changes in grain boundary composition induced by neutron irradiation of austenitic stainless steels

    International Nuclear Information System (INIS)

    Asano, K.; Nakata, K.; Fukuya, K.; Kodama, M.

    1992-01-01

    The radiation induced segregation of solutes to the grain boundary in austenitic stainless steels were studied. Type 304 and type 316 steel samples neutron irradiated at 561K up to 9.2x10 25 n/m 2 were obtained and minute compositional profiles across grain boundaries were examined using an analytical scanning transmission electron microscope equipped with a field emission electron gun. Chromium was slightly enriched at grain boundaries at the lowest irradiation dose but decreased with increasing fluence. Higher fluence irradiation resulted in depletion in chromium and molybdenum, and enrichment in nickel, silicon and phosphorus. These changes in grain boundary chemistry were limited within about 5nm of the boundary. Significant depletion of chromium and enrichment of impurities on the grain boundary occurred at fluences roughly coincidental with that of SCC susceptibility change obtained from another project

  13. Atom probe, AFM and STM study on vacuum fired stainless steel

    International Nuclear Information System (INIS)

    Stupnik, A.; Frank, P.; Leisch, M.

    2008-01-01

    Full text: Stainless steel is one of the most commonly used structural materials for vacuum equipment. An efficient method to reduce the outgassing rate from stainless steel is a high temperature bakeout in vacuum (vacuum firing). This procedure reduces significantly the amount of dissolved hydrogen in the bulk. For the outgassing process the recombination rate of hydrogen atoms to the molecules plays the determining role and recombination is strongly related to the surface structure and composition. To get more detailed information about the surface morphology and composition AFM, STM and atom probe studies were carried out. Experiments on AISI 304L stainless steel samples show that the surface reconstructs completely during vacuum firing and large atomically flat terraces bounded by bunched steps and facets are formed. The large flat terraces can be assigned to (111) planes. The bunched steps and facets are corresponding in orientation almost to (110) planes and (100) planes. Surface inspection after vacuum firing by Auger electron spectroscopy (AES) gives reason for a composition change indicated by a reduction of the chromium signal in relation to the iron and nickel signal. Since the information depth of AES covers several atomic layers not only the top atomic layer of the sample surface is probed. For this reason 3D atom probe was used as well suited tool to investigate the segregation behavior of this alloy with the goal to examine the change in local chemical composition due to the high temperature treatment. As a result of vacuum firing the atom probe experiments show a significant enrichment of nickel at the top surface layer. In the second atomic layer chromium enrichment is detected. After vacuum firing the average composition below the second atomic layer shows certain chromium depletion up to 2 nm in depth. The observed changes in surface chemistry influence recombination and desorption probability from the surface and may contribute to the present

  14. Desensitization of stainless steels by laser surface heat-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, Yoshikuni; Nishimoto, Kazutoshi

    1987-11-01

    Laser heating was applied for the desensitization heat-treatment of the surface layer in the sensitized HAZ of Type 304 stainless steel. The degree of sensitization was examined by EPR technique and the 10 % oxalic acid electrolytic etch test. The CO/sub 2/ laser with maximum power of 1.5 kW was used for heat-treatment. Time-Temperature-Desensitization diagram (TTDS diagram) for sensitized Type 304 stainless steels were developed by calculation assuming the chromium diffusion control for desensitization which might occur when the chromium depleted zone was healed up due to dissolution of chromium carbide and chromium diffusion from the matrix being heated at the solution annealing temperatures. TTDS diagrams calculated agree fairly well with ones determined by corrosion tests. Laser irradiation conditions (e.g., Laser power, beam diameter and traveling velocity) required for desensitization of sensitized Type 304 stainless steels were calculated using additivity rule from the TTDS diagram calculated and theoretical thermal curve of laser heating derived from the heat conduction theory. After laser beam irradiated under an optimum condition predicted by calculation, the sensitized HAZ of Type 304 stainless steel restored complete resistance to intergranular corrosion.

  15. Properties of super stainless steels for orthodontic applications.

    Science.gov (United States)

    Oh, Keun-Taek; Kim, Young-Sik; Park, Yong-Soo; Kim, Kyoung-Nam

    2004-05-15

    Orthodontic stainless-steel appliances are considered to be corrosion resistant, but localized corrosion can occur in the oral cavity. This study was undertaken to evaluate the properties of super stainless steels in orthodontic applications. Accordingly, the metallurgical properties, mechanical properties, corrosion resistance, amount of the released nickel, cytotoxicity, and characteristics of the passive film were investigated. Corrosion resistances of the specimens were high and in the following order: super austenitic stainless steel (SR-50A) > super ferritic stainless steel (SFSS) = super duplex stainless steel (SR-6DX) > 316L SS > super martensitic stainless steel (SR-3Mo) in artificial saliva, 37 degrees C. At 500 mV (SCE), current densities of SR-50A, SFSS, SR-6DX, 316L SS, and SR-3Mo were 5.96 microA/cm(2), 20.3 microA/cm(2), 31.9 microA/cm(2), 805 microA/cm(2), and 5.36 mA/cm(2), respectively. Open circuit potentials of SR-50A, 316L SS, SR-6DX, SR-3Mo, and SFSS were - 0.2, - 0.22, - 0.24, - 0.43, and - 0.46 V (SCE), respectively. SR-50A, SFSS, and SR-6DX released below 3 ng/ml nickel for 8 weeks, and increased a little with immersion time, and 316L SS released about 3.5 ng/ml nickel, but SR-3Mo released a large amount of nickel, which increased with immersion time. The study demonstrated that SR-50A, SR-6DX, and SFSS have high corrosion resistance and mild or no cytotoxicity, due to the passive film enhanced by synergistic effect of Mo + N or by high addition effect of Cr + W. All super stainless steels showed very low cytotoxicity regardless of their nickel contents, although SR-3Mo was found to be relatively cytotoxic. From these studies, these steels are considered suitable for orthodontic applications. Copyright 2004 Wiley Periodicals, Inc.

  16. Human biomonitoring of chromium and nickel from an experimental exposure to manual metal arc welding fumes of low and high alloyed steel.

    Science.gov (United States)

    Bertram, Jens; Brand, Peter; Schettgen, Thomas; Lenz, Klaus; Purrio, Ellwyn; Reisgen, Uwe; Kraus, Thomas

    2015-05-01

    The uptake and elimination of metals from welding fumes is currently not fully understood. In the Aachen Workplace Simulation Laboratory (AWSL) it is possible to investigate the impact of welding fumes on human subjects under controlled exposure conditions. In this study, the uptake and elimination of chromium or chromium (VI) respectively as well as nickel was studied in subjects after exposure to the emissions of a manual metal arc welding process using low or high alloyed steel. In this present study 12 healthy male non-smokers, who never worked as welders before, were exposed for 6h to welding fumes of a manual metal arc welding process. In a three-fold crossover study design, subjects were exposed in randomized order to either clean air, emissions from welding low alloyed steel, and emissions from welding high alloyed steel. Particle mass concentration of the exposure aerosol was 2.5mg m(-3). The content of chromium and nickel in the air was determined by analysing air filter samples on a high emission scenario. Urine analysis for chromium and nickel was performed before and after exposure using methods of human biomonitoring. There were significantly elevated chromium levels after exposure to welding fumes from high alloyed steel compared to urinary chromium levels before exposure to high alloyed welding fumes, as well as compared to the other exposure scenarios. The mean values increased from 0.27 µg l(-1) to 18.62 µg l(-1). The results were in good agreement with already existing correlations between external and internal exposure (German exposure equivalent for carcinogenic working materials EKA). The variability of urinary chromium levels was high. For urinary nickel no significant changes could be detected at all. Six-hour exposure to 2.5mg m(-3) high alloyed manual metal arc welding fumes lead to elevated urinary chromium levels far higher (7.11-34.16 µg l(-1)) than the German biological exposure reference value (BAR) of 0.6 µg l(-1) directly after

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

    Science.gov (United States)

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

    1979-01-01

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

  18. Study of cast and thermo-mechanically strengthened chromium-nickel nitrogen-containing steel

    International Nuclear Information System (INIS)

    Prokoshkina, V.G.; Kaputkina, L.M.; Svyazhin, A.G.

    2000-01-01

    The effect of nitrogen on the structure and strength of corrosion-resistant chromium-nickel steels after thermal and thermomechanical treatment is studied. The 06Kh15N7AD and 07Kh15N7DAMB steels alloying by nitrogen was accomplished through the basic composition steels remelting in the molecular nitrogen atmosphere under the pressure of 0.1-2.5 MPa. The 02Kh15N5DAF and 05Kh15N5DAM steels ingots were obtained through melting in a plasma furnace under the nitrogen pressure of 0.4MPA. The high-temperature thermomechanical treatment (HTMT) was performed by rolling with preliminary blanks heating up to 1050 deg C and the rolling end temperature not below 950 deg C. It is shown, that the HTMT of the nitrogen-containing steels makes it possible to obtain strength characteristics by 1.5 times exceeding the properties of traditionally applicable corrosion-resistant steels, whereby sufficiently high plasticity of the nitrogen-containing steel is retained [ru

  19. Aging behaviour of 25Cr-17Mn high nitrogen duplex stainless steel

    OpenAIRE

    Machado, I. F.; Padilha, A. F.

    2000-01-01

    The precipitation behaviour of a nickel free stainless steel containing 25% chromium, 17% manganese and 0.54% nitrogen, with duplex ferritic-austenitic microstructure, was studied using several complementary techniques of microstructural analysis after aging heat treatments between 600 and 1 000 degrees C for periods of lime between 15 and 6 000 min. During aging heat treatments, ferrite was decomposed into sigma phase and austenite by a eutectoid reaction, like in the Fe-Cr-Ni duplex stainle...

  20. Pyrolysis-catalysis of waste plastic using a nickel-stainless-steel mesh catalyst for high-value carbon products.

    Science.gov (United States)

    Zhang, Yeshui; Nahil, Mohamad A; Wu, Chunfei; Williams, Paul T

    2017-11-01

    A stainless-steel mesh loaded with nickel catalyst was produced and used for the pyrolysis-catalysis of waste high-density polyethylene with the aim of producing high-value carbon products, including carbon nanotubes (CNTs). The catalysis temperature and plastic-to-catalyst ratio were investigated to determine the influence on the formation of different types of carbon deposited on the nickel-stainless-steel mesh catalyst. Increasing temperature from 700 to 900°C resulted in an increase in the carbon deposited on the nickel-loaded stainless-steel mesh catalyst from 32.5 to 38.0 wt%. The increase in sample-to-catalyst ratio reduced the amount of carbon deposited on the mesh catalyst in terms of g carbon g -1 plastic. The carbons were found to be largely composed of filamentous carbons, with negligible disordered (amorphous) carbons. Transmission electron microscopy analysis of the filamentous carbons revealed them to be composed of a large proportion (estimated at ∼40%) multi-walled carbon nanotubes (MWCNTs). The optimum process conditions for CNT production, in terms of yield and graphitic nature, determined by Raman spectroscopy, was catalysis temperature of 800°C and plastic-to-catalyst ratio of 1:2, where a mass of 334 mg of filamentous/MWCNTs g -1 plastic was produced.

  1. XPS and SEM studies of chromium oxide films chemically formed on stainless steel 316 L

    International Nuclear Information System (INIS)

    Stefanov, P.; Marinova, T.

    2000-01-01

    The structure and composition of chromium oxide films formed on stainless steel by immersion in a chromium electrolyte have been studied by SEM and XPS. Cr 2 O 3 crystallites in the range 30-150 nm are fully developed and cover the whole surface. The chemical composition in the depth and the thickness of the oxide layer have been determined by XPS sputter profiles. The oxide film can be described within the framework of a double layer consisting of a thin outer hydrated layer and an inner layer of Cr 2 O 3 . (orig.)

  2. Evaluation of the Pulmonary Toxicity of a Fume Generated from a Nickel-, Copper-Based Electrode to be Used as a Substitute in Stainless Steel Welding

    Science.gov (United States)

    Antonini, James M; Badding, Melissa A; Meighan, Terence G; Keane, Michael; Leonard, Stephen S; Roberts, Jenny R

    2014-01-01

    Epidemiology has indicated a possible increase in lung cancer among stainless steel welders. Chromium (Cr) is a primary component of stainless steel welding fume. There is an initiative to develop alternative welding consumables [nickel (Ni)- and copper (Cu)-based alloys] that do not contain Cr. No study has been performed to evaluate the toxicity of fumes generated from Ni- and Cu-based consumables. Dose–response and time-course effects on lung toxicity of a Ni- and Cu-based welding fume (Ni–Cu WF) were examined using an in vivo and in vitro bioassay, and compared with two other well-characterized welding fumes. Even though only trace amounts of Cr were present, a persistent increase in lung injury and inflammation was observed for the Ni–Cu WF compared to the other fumes. The difference in response appears to be due to a direct cytotoxic effect by the Ni–Cu WF sample on lung macrophages as opposed to an elevated production of reactive oxygen species (ROS). PMID:25392698

  3. Systemic nickel: the contribution made by stainless-steel cooking utensils.

    Science.gov (United States)

    Flint, G N; Packirisamy, S

    1995-04-01

    An extensive programme of cooking operations, using household recipes, has shown that, apart from aberrant values associated with new pans on first use, the contribution made by 19 Cr/9 Ni stainless-steel cooking utensils to nickel in the diet is negligible. The amount of nickel (0 to 8 micrograms) derived from the utensils in standard portions of various "aggressive" foodstuffs tested was less than that to be found occurring in 1 square of a bitter-sweet chocolate bar. New pans, if first used with acid fruits, can show a greater pick-up of nickel, which, in the worst case observed, amounted to approximately 1/5 of the normal daily intake for the average person (ca. 200 micrograms). This situation does not recur in subsequent usage, even after the pan has been cleaned by abrasion. A higher rate of nickel release was observed in new pans on first use from 4 manufacturers located in different countries and appears to be a general phenomenon. This could provide a possible explanation for the high pick-up of nickel by acid fruits reported in 1 instance in the literature.

  4. Precipitation of Chromium Nitrides in the Super Duplex Stainless Steel 2507

    Science.gov (United States)

    Pettersson, Niklas; Pettersson, Rachel F. A.; Wessman, Sten

    2015-03-01

    Precipitation of chromium nitrides during cooling from temperatures in the range 1373 K to 1523 K (1100 °C to 1250 °C) has been studied for the super duplex stainless steel 2507 (UNS S32750). Characterization with optical, scanning and transmission electron microscopy was combined to quantify the precipitation process. Primarily Cr2N nitrides were found to precipitate with a high density in the interior of ferrite grains. An increased cooling rate and/or an increased austenite spacing clearly promoted nitride formation, resulting in precipitation within a higher fraction of the ferrite grains, and lager nitride particles. Furthermore, formation of the meta-stable CrN was induced by higher cooling rates. The toughness seemed unaffected by nitrides. A slight decrease in pitting resistance was, however, noticed for quenched samples with large amounts of precipitates. The limited adverse effect on pitting resistance is attributed to the small size (~200 nm) of most nitrides. Slower cooling of duplex stainless steels to allow nitrogen partitioning is suggested in order to avoid large nitrides, and thereby produce a size distribution with a smaller detrimental effect on pitting resistance.

  5. Heat treatment temperature influence on ASTM A890 GR 6A super duplex stainless steel microstructure

    International Nuclear Information System (INIS)

    Martins, Marcelo; Casteletti, Luiz Carlos

    2005-01-01

    Duplex and super duplex stainless steels are ferrous alloys with up to 26% chromium, 8% nickel, 5% molybdenum and 0.3% nitrogen, which are largely used in applications in media containing ions from the halogen family, mainly the chloride ion (Cl - ). The emergence of this material aimed at substituting Copper-Nickel alloys (Cupro-Nickel) that despite presenting good corrosion resistance, has mechanical properties quite inferior to steel properties. The metallurgy of duplex and super duplex stainless steel is complex due to high sensitiveness to sigma phase precipitation that becomes apparent, due to the temperatures they are exposed on cooling from solidification as well as from heat treatment processes. The objective of this study was to verify the influence of heat treating temperatures on the microstructure and hardness of ASTM A890/A890M Gr 6A super duplex stainless steel type. Microstructure control is of extreme importance for castings, as the chemical composition and cooling during solidification inevitably provide conditions for precipitation of sigma phase. Higher hardness in these materials is directly associated to high sigma phase concentration in the microstructure, precipitated in the ferrite/austenite interface. While heat treatment temperature during solution treatment increases, the sigma phase content in the microstructure decreases and consequently, the material hardness diminishes. When the sigma phase was completely dissolved by the heat treatment, the material hardness was influenced only due to ferrite and austenite contents in the microstructure

  6. Dissolution mechanism of austenitic stainless steels in lead-bismuth eutectic at 500 deg. C

    International Nuclear Information System (INIS)

    Roy, M.

    2012-01-01

    In the framework of the future nuclear power plants studies, lead-bismuth eutectic (LBE) is foreseen as a coolant in the primary or the secondary circuit in three nuclear systems. The use of this liquid alloy induces corrosion issues for structural steels. In liquid lead alloys, steels can undergo two corrosion phenomena: dissolution or oxidation depending on the temperature and the dissolved oxygen content in LBE. The goal of this study is to identify the dissolution mechanisms of austenitic steels in LBE at 500 deg. C. Four Fe-Cr-Ni model austenitic steels, the 316L steel and five other industrial steels were corroded in LBE up to, respectively, 3000, 6000 and 200 h. The dissolution mechanism is identical for all steels: it starts by a preferential dissolution of chromium and nickel. This dissolution leads to the formation of a ferritic corrosion layer penetrated by LBE and containing between 5 and 10 at% of chromium and almost no nickel. This study demonstrates that dissolutions of nickel and chromium are linked. Otherwise, the corrosion kinetics is linear whatever the tested austenitic steel. The controlling steps of the austenitic steels' corrosion rates have been identified. Natural convection in the LBE bath leads to the formation of a diffusion boundary layer at the steel surface. Chromium diffusion in this diffusion boundary layer seems to control the corrosion rates of the model and industrial austenitic steels except the 316L steel. Indeed, the corrosion rate of the 316L steel is controlled by an interfacial reaction which is either the simultaneous dissolution of nickel and chromium in Ni, Cr compounds or the nickel and chromium dissolution catalyzed by the dissolved oxygen in LBE. This study has permitted to highlight the major role of chromium on the corrosion mechanisms and the corrosion rates of austenitic steels: the corrosion rate increases when chromium activity increases. Finally, the impact of the dissolved oxygen and the minor alloying

  7. Ion-nitriding of austenitic stainless steels

    International Nuclear Information System (INIS)

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

    1995-01-01

    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

  8. A preliminary investigation of the initiation of pitting corrosion in austenitic stainless steels and nickel-based alloys

    International Nuclear Information System (INIS)

    Higginson, A.

    1984-01-01

    Pitting corrosion in a number of austenitic stainless steels and nickel-based alloys that differ widely in their resistance to corrosion was studed by electrochemical and electron-optical techniques. The effect of contamination of the sulphuric acid electrolyte by chloride ions was also investigated. Preliminary results for the surface analysis of samples of 316 stainless steel by Auger electron spectroscopy are presented, and suggestions are included for further application of this technique to the examination of pitting corrosion. A comprehensive review of the literature concerning the initiation of pitting corrosion is included

  9. Adverse effects of nickel in transosseous wires and surgical implants: literature review.

    Science.gov (United States)

    Nwashindi, A; Dim, E M

    2014-01-01

    Transosseous wires used in the management of fractures are stainless steel alloys which contain nickel 14.5%, chromium 17.6%, iron 62.5% and molybdenum 2.8%. Gradual disintegration of the transosseous wires release nickel into the blood leading to increase nickel concentration in the blood. Nickel has been found to have some adverse systemic effects on the body. The aim of this paper is to discuss the sources of Nickel in the body as well as the systemic adverse effects of Nickel as a degradation product of stainless steel surgical implants. A study of pertinent literature on nickel as a content of stainless steel alloy used in implant surgery was done, taking note also of other sources of nickel in the body, the toxicokinetics of nickel and the related adverse effects of this metal and its compound in humans. As outcome,the sources of human exposure to nickel,distribution and metabolism of nickel in the body, host responseto stainless steel wires and the adverse effects of nickel in the body are presented. It may be necessary to discourage the use of wires or implants containing nickel in the management of fractures.The need for removal of these implants after they have served their purposes is emphasized.

  10. Influence of pH on the chemical and structural properties of the oxide films formed on 316L stainless steel, alloy 600 and alloy 690 in high temperature aqueous environments

    International Nuclear Information System (INIS)

    Dupin, M.; Gosser, P.; Walls, M.G.; Rondot, B.; Pastol, J.L.

    2002-01-01

    The oxide films formed on 316L stainless steel, alloy 600 and alloy 690 at 320 deg C in high temperature aqueous environments of different pH have been examined by glow discharge optical spectroscopy, scanning electron microscopy, atomic force microscopy and capacitance measurements. The analytical study reveals that the films formed at pH 5 are mainly composed of chromium oxides. When the pH increases the chromium concentration decreases and those of the other two elements (Ni and Fe) tend to increase. The films formed at pH 5 on 316L stainless steel and alloy 600 are thick and powder-like. The film formed at the same pH on alloy 690 is thin and is composed of a compact protective inner layer and a less-compact outer layer formed by crystals of mixed iron-nickel-chromium oxides. The morphological appearance of the thick films and that of the thin films is very different. However, equivalent morphologies can be observed for the relatively thin duplex films formed at pH 8 and pH 9.5 on the 316L stainless steel and nickel-base alloys. The evolution of the chemical composition of the films is accompanied by important changes from the point of view of their semi-conductivity. (authors)

  11. The use of stainless steel and nickel alloys as low-cost cathodes in microbial electrolysis cells

    KAUST Repository

    Selembo, Priscilla A.

    2009-05-01

    Microbial electrolysis cells (MECs) are used to produce hydrogen gas from the current generated by bacteria, but low-cost alternatives are needed to typical cathode materials (carbon cloth, platinum and Nafion™). Stainless steel A286 was superior to platinum sheet metal in terms of cathodic hydrogen recovery (61% vs. 47%), overall energy recovery (46% vs. 35%), and maximum volumetric hydrogen production rate (1.5 m3 m-3 day-1 vs. 0.68 m3 m-3 day-1) at an applied voltage of 0.9 V. Nickel 625 was better than other nickel alloys, but it did not perform as well as SS A625. The relative ranking of these materials in MEC tests was in agreement with cyclic voltammetry studies. Performance of the stainless steel and nickel cathodes was further increased, even at a lower applied voltage (0.6 V), by electrodepositing a nickel oxide layer onto the sheet metal (cathodic hydrogen recovery, 52%, overall energy recovery, 48%; maximum volumetric hydrogen production rate, 0.76 m3 m-3 day-1). However, performance of the nickel oxide cathodes decreased over time due to a reduction in mechanical stability of the oxides (based on SEM-EDS analysis). These results demonstrate that non-precious metal cathodes can be used in MECs to achieve hydrogen gas production rates better than those obtained with platinum. © 2009 Elsevier B.V. All rights reserved.

  12. The use of stainless steel and nickel alloys as low-cost cathodes in microbial electrolysis cells

    KAUST Repository

    Selembo, Priscilla A.; Merrill, Mathew D.; Logan, Bruce E.

    2009-01-01

    Microbial electrolysis cells (MECs) are used to produce hydrogen gas from the current generated by bacteria, but low-cost alternatives are needed to typical cathode materials (carbon cloth, platinum and Nafion™). Stainless steel A286 was superior to platinum sheet metal in terms of cathodic hydrogen recovery (61% vs. 47%), overall energy recovery (46% vs. 35%), and maximum volumetric hydrogen production rate (1.5 m3 m-3 day-1 vs. 0.68 m3 m-3 day-1) at an applied voltage of 0.9 V. Nickel 625 was better than other nickel alloys, but it did not perform as well as SS A625. The relative ranking of these materials in MEC tests was in agreement with cyclic voltammetry studies. Performance of the stainless steel and nickel cathodes was further increased, even at a lower applied voltage (0.6 V), by electrodepositing a nickel oxide layer onto the sheet metal (cathodic hydrogen recovery, 52%, overall energy recovery, 48%; maximum volumetric hydrogen production rate, 0.76 m3 m-3 day-1). However, performance of the nickel oxide cathodes decreased over time due to a reduction in mechanical stability of the oxides (based on SEM-EDS analysis). These results demonstrate that non-precious metal cathodes can be used in MECs to achieve hydrogen gas production rates better than those obtained with platinum. © 2009 Elsevier B.V. All rights reserved.

  13. An in vitro comparison of nickel and chromium release from brackets

    Directory of Open Access Journals (Sweden)

    Ana Cristina Soares Santos Haddad

    2009-12-01

    Full Text Available This study aimed at comparing amounts of nickel (Ni and chromium (Cr released from brackets from different manufacturers in simulated oral environments. 280 brackets were equally divided into 7 groups according to manufacturer. 6 groups of brackets were stainless steel, and 1 group of brackets was made of a cobalt-chromium alloy with low Ni content (0.5%. International standard ISO 10271/2001 was applied to provide test methods. Each bracket was immersed in 0.5 ml of synthetic saliva (SS or artificial plaque fluid (PF over a period of 28 days at 37ºC. Solutions were replaced every 7 days, and were analyzed by spectrometry. The Kruskal-Wallis test was applied. Amounts of Ni release in SS (µg L-1 per week varied between groups from "bellow detection limits" to 694, and from 49 to 5,948.5 in PF. The group of brackets made of cobalt-chromium alloy, with the least nickel content, did not release the least amounts of Ni. Amounts of Cr detected in SS and in PF (µg L-1 per week were from 1 to 10.4 and from 50.5 to 8,225, respectively. It was therefore concluded that brackets from different manufacturers present different corrosion behavior. Further studies are necessary to determine clinical implications of the findings.

  14. Impact of Magnetic Stirring on Stainless Steel Integrity: Effect on Biopharmaceutical Processing.

    Science.gov (United States)

    Thompson, Christopher; Wilson, Kelly; Kim, Yoen Joo; Xie, Min; Wang, William K; Wendeler, Michaela

    2017-11-01

    Stainless steel containers are widely used in the pharmaceutical and biopharmaceutical industry for the storage of buffers, process intermediates, and purified drug substance. They are generally held to be corrosion resistant, biocompatible, and nonreactive, although it is well established that trace amounts of metal ions can leach from stainless steel equipment into biopharmaceutical products. We report here that the use of stainless steel containers in conjunction with magnetic stirring bars leads to significantly aggravated metal contamination, consisting of both metal particles and significantly elevated metal ions in solution, the degree of which is several orders of magnitude higher than described for static conditions. Metal particles are analyzed by scanning electron microscopy with electron-dispersive X-ray spectroscopy, and metal content in solution is quantitated at different time points by inductively coupled plasma-mass spectrometry. The concentration of iron, chromium, nickel, and manganese increases with increasing stirring time and speed. We describe the impact of buffer components on the extent of metal particles and ions in solution and illustrate the effect on model proteins. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  15. Reduced-activation austenitic stainless steels: The Fe--Mn--Cr--C system

    International Nuclear Information System (INIS)

    Klueh, R.L.; Maziasz, P.J.

    1988-01-01

    Nickel-free manganese-stabilized steels are being developed for fusion-reactor applications. As the first part of this effort, the austenite-stable region in the Fe--Mn--Cr--C system was determined. Results indicated that the Schaeffler diagram developed for Fe--Ni--Cr--C alloys cannot be used to predict the constituents expected for high-manganese steels. This is true because manganese is not as strong an austenite stabilizer relative to δ-ferrite formation as predicted by the diagram, but it is a stronger austenite stabilizer relative to martensite than predicted. Therefore, the austenite-stable region for Ne--Mn--Cr--C alloys occurs at lower chromium and hugher combinations of manganese and carbon than predicted by the Schaeffler diagram. Development of a manganese-stabilized stainless steel should be possible in the composition range of 20 to 25% Mn, 10 to 15% Cr, and 0.01 to 0.25%C. Tensile behavior of an Fe--20%Mn--12%Cr--0.25%C alloy was determined. The strength and ductility of this possible base composition was comparable to type 316 stainless steel in both the solution-annealed and cold-worked condition

  16. Release of nickel and chromium ions in the saliva of patients with fixed orthodontic appliance: An in-vivo study.

    Science.gov (United States)

    Dwivedi, Anoop; Tikku, Tripti; Khanna, Rohit; Maurya, Rana Pratap; Verma, Geeta; Murthy, R C

    2015-01-01

    Various components of fixed orthodontic appliances are continuously interacting with saliva and other fluids in the mouth releasing various metal ions including nickel and chromium that can cause damaging effects if their concentration exceeds above the toxic dose. To determine and compare the level of nickel and chromium in the saliva of patients undergoing fixed orthodontic treatment at different time periods. The sample of saliva of 13 patients was taken at different time periods that is: Group 1 (before appliance placement), Group II, III, and IV (after 1-week, 1-month, and 3 months of appliance placement respectively). The fixed appliance comprised of brackets, bands, buccal tubes, lingual sheath, transpalatal arch and wires composed of Ni-Ti and stainless steel. The level of ions was determined using graphite furnace atomic absorption spectro-photometry. The data thus obtained were statistically analyzed using SPSS Statistical Analysis Software (Version 15.0). Level of nickel and chromium in saliva was highest in Group II and lowest in Groups I for both the ions. On comparison among different Groups, it was statistically significant for all the groups (<0.001) except between Group III and Group IV. The release of nickel and chromium was maximum at 1-week and then the level gradually declined. These values were well below the toxic dose of these ions. The results should be viewed with caution in subjects with Ni hypersensitivity.

  17. Mass transfer behavior of a modified austenitic stainless steel in lithium

    International Nuclear Information System (INIS)

    Tortorelli, P.F.; DeVan, J.H.

    1983-01-01

    An austenitic stainless steel that was developed to resist neutron damage was exposed to lithium in the high-temperature part of a thermal convection loop for 6700 h. Specimens of this Prime Candidate Alloy (PCA) composed of 65.0 Fe-15.9 Ni-13.0 Cr-1.9 Mo-1.9 Mn-1.7 Si-0.5 Ti-0.05 C (wt %) were exposed at 600 and 570 0 C in both solution annealed and cold worked forms. The dissolution process was found to be similar to other austenitic alloys in flowing lithium: weight losses of PCA eventually became linearly proportional to exposure time with the specimen surfaces exhibiting porous layers depleted in nickel and chromium. However, the measured weight losses and dissolution rates of these PCA specimens were higher than those of type 316 stainless steel exposed under similar conditions and can be attributed to the higher nickel concentration of the former alloy. The effect of cold work on dissolution rates was less definitive, particularly at 570 0 C. At longer exposure times, the annealed PCA specimen exposed at 600 0 C suffered greater dissolution than the cold worked material, while no effect of prior deformation was observed by analysis of the respective surfaces

  18. Microstructural stability of fast reactor irradiated 10 to 12% Cr ferritic-martensitic stainless steels

    International Nuclear Information System (INIS)

    Little, E.A.; Stoter, L.P.

    1982-01-01

    The strength and microstructural stability of three 10 to 12% Cr ferritic-martensitic stainless steels have been characterized following fast reactor irradiation to damage levels of 30 displacements per atom (dpa) at temperatures in the range 380 to 615 0 C. Irradiation results in either increases or decreases in room temperature hardness depending on the irradiation temperature. These strength changes can be qualitatively rationalized in terms of the combined effects of irradiation-induced interstitial dislocation loop formation and recovery of the dislocation networks comprising the initial tempered martensite structures. Precipitate evolution in the irradiated steels is associated with the nonequilibrium segregation of the elements nickel, silicon, molybdenum, chromium and phosphorus, brought about by solute-point defect interactions. The principal irradiation-induced precipitates identified are M 6 X, intermetallic chi and sigma phases and also α' (Cr-rich ferrite). The implications of the observed microstructural changes on the selection of martensitic stainless steels for fast reactor wrapper applications are briefly considered

  19. Corrosion of stainless steels and nickel-base alloys in solutions of nitric acid and hydrofluoric acid

    International Nuclear Information System (INIS)

    Horn, E.M.; Renner, M.

    1992-01-01

    Reactions involving nitric acid may always result in the contamination of this acid with fluorides. In highly concentrted nitric acid, the presence of small amounts of HF will substantially reduce the corrosion of metallic materials. Mixtures consisting of hydrofluoric acid and hypo-azeotropic nitric acid on the other hand will strongly attack: the metal loss will markedly increase with increasing HNO 3 and HF concentrations as well as with rising temperatures. The investigation covered 12 stainless steel grades and nickel-base alloys. With constant HNO 3 content, corrosion rates will rise linearly when increasing the HF concentration. With constant HF concentration (0,25 M), corrosion rates will increase rapidly with increasing nitric acid concentration (from 0.3 M to 14.8 M). This can best be described by superimposing a linear function and a hyperbolic function that is reflecting the change in the HNO 3 content. Alloys containing as much chromium as possible (up to 46 wt.%) will exhibit the best corrosion resistance. Alloy NiCr30FeMo (Hastelloy alloy G-30) proved to be well suitable in this investigation. (orig.) [de

  20. Assessment of biological chromium among stainless steel and mild steel welders in relation to welding processes.

    Science.gov (United States)

    Edmé, J L; Shirali, P; Mereau, M; Sobaszek, A; Boulenguez, C; Diebold, F; Haguenoer, J M

    1997-01-01

    Air and biological monitoring were used for assessing external and internal chromium exposure among 116 stainless steel welders (SS welders) using manual metal arc (MMA), metal inert gas (MIG) and tungsten inert gas (TIG) welding processes (MMA: n = 57; MIG: n = 37; TIG: n = 22) and 30 mild steel welders (MS welders) using MMA and MIG welding processes (MMA: n = 14; MIG: n = 16). The levels of atmospheric total chromium were evaluated after personal air monitoring. The mean values for the different groups of SS welders were 201 micrograms/m3 (MMA) and 185 micrograms/m3 (MIG), 52 micrograms/m3 (TIG) and for MS welders 8.1 micrograms/m3 (MMA) and 7.3 micrograms/m3 (MIG). The curve of cumulative frequency distribution from biological monitoring among SS welders showed chromium geometric mean concentrations in whole blood of 3.6 micrograms/l (95th percentile = 19.9), in plasma of 3.3 micrograms/l (95th percentile = 21.0) and in urine samples of 6.2 micrograms/l (95th percentile = 58.0). Among MS welders, mean values in whole blood and plasma were rather more scattered (1.8 micrograms/l, 95th percentile = 9.3 and 1.3 micrograms/l, 95th percentile = 8.4, respectively) and in urine the value was 2.4 micrograms/l (95th percentile = 13.3). The analysis of variance of chromium concentrations in plasma previously showed a metal effect (F = 29.7, P process effect (F = 22.2, P process interaction (F = 1.3, P = 0.25). Concerning urinary chromium concentration, the analysis of variance also showed a metal effect (F = 30, P process effect (F = 72, P process interaction (F = 13.2, P = 0.0004). Throughout the study we noted any significant differences between smokers and non-smokers among welders. Taking in account the relationships between chromium concentrations in whole, plasma or urine and the different welding process. MMA-SS is definitely different from other processes because the biological values are clearly higher. These higher levels are due to the very significant

  1. Corrosion behaviour of stainless steels by internal friction method

    International Nuclear Information System (INIS)

    Postnikov, V.S.; Kovalevskij, V.I.

    1987-01-01

    Corrosion of austenite chromium-nickel stainless steels 12 Kh18N9, 12Kh18N9T, 12Kh18N10 and 12Kh18N10T is investigated. Wire samples 0.7...0.8 mm in diameter before tests were subjected to quenching in water from the temperature of 1050...1100 deg C and part of them - to tempering at 650 deg C for 2 h. Pitting corrosion was brought about by different concentration of iron chloride solutions (C FeCl 3 ). Total corrosion has a slight effect on the character of IF (internal friction) variation that increases without the whole test period up to the moment when mechanical strength of the sample

  2. Depth distribution of martensite in xenon implanted stainless steels

    International Nuclear Information System (INIS)

    Johansen, A.; Johnson, E.; Sarholt-Kristensen, L.; Steenstrup, S.; Hayashi, N.; Sakamoto, I.

    1989-01-01

    The amount of stress-induced martensite and its distribution in depth in xenon implanted austenitic stainless steel poly- and single crystals have been measured by Rutherford backscattering and channeling analysis, depth selective conversion electron Moessbauer spectroscopy, cross-sectional transmission electron microscopy and x-ray diffraction analysis. In low nickel 17/7, 304 and 316 commercial stainless steels and in 17:13 single crystals the martensitic transformation starts at the surface and develops towards greater depth with increasing xenon fluence. The implanted layer is nearly completely transformed, and the interface between martensite and austenite is rather sharp and well defined. In high nickel 310 commercial stainless steel and 15:19 and 20:19 single crystals, on the other hand, only insignificant amounts of martensite are observed. (orig.)

  3. Solidification behavior of austenitic stainless steel filler metals

    International Nuclear Information System (INIS)

    David, S.A.; Goodwin, G.M.; Braski, D.N.

    1980-02-01

    Thermal analysis and interrupted solidification experiments on selected austenitic stainless steel filler metals provided an understanding of the solidification behavior of austenitic stainless steel welds. The sequences of phase separations found were for type 308 stainless steel filler metal, L + L + delta + L + delta + γ → γ + delta, and for type 310 stainless steel filler metal, L → L + γ → γ. In type 308 stainless steel filler metal, ferrite at room temperature was identified as either the untransformed primary delta-ferrite formed during the initial stages of solidification or the residual ferrite after Widmanstaetten austenite precipitation. Microprobe and scanning transmission electron microscope microanalyses revealed that solute extensively redistributes during the transformation of primary delta-ferrite to austenite, leading to enrichment and stabilization of ferrite by chromium. The type 310 stainless steel filler metal investigated solidifies by the primary crystallization of austenite, with the transformation going to completion at the solidus temperature. In our samples residual ferrite resulting from solute segregation was absent at the intercellular or interdendritic regions

  4. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Serdar, Marijana [Department of Materials, Faculty of Civil Engineering, University of Zagreb, 10000 Zagreb (Croatia); Meral, Cagla [Middle East Technical University, Department of Civil Engineering, Ankara (Turkey); Kunz, Martin [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Bjegovic, Dubravka [Department of Materials, Faculty of Civil Engineering, University of Zagreb, 10000 Zagreb (Croatia); Wenk, Hans-Rudolf [Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 (United States); Monteiro, Paulo J.M., E-mail: monteiro@ce.berkeley.edu [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2015-05-15

    The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide–hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel. - Highlights: • Synchrotron micro-diffraction used to map the distribution of crystalline phases. • Goethite and akaganeite are the main corrosion products during chloride induced corrosion in mortar. • Layers of goethite and akaganeite are negatively correlated. • EDS showed Cr present in corrosion products identified by SEM.

  5. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    International Nuclear Information System (INIS)

    Serdar, Marijana; Meral, Cagla; Kunz, Martin; Bjegovic, Dubravka; Wenk, Hans-Rudolf; Monteiro, Paulo J.M.

    2015-01-01

    The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide–hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel. - Highlights: • Synchrotron micro-diffraction used to map the distribution of crystalline phases. • Goethite and akaganeite are the main corrosion products during chloride induced corrosion in mortar. • Layers of goethite and akaganeite are negatively correlated. • EDS showed Cr present in corrosion products identified by SEM

  6. Investigation of alternative phosphating treatments for nickel and hexavalent chromium elimination

    International Nuclear Information System (INIS)

    Jazbinsek, Luiz Antonio Rossi

    2014-01-01

    The phosphating processes are widely used in industry as surface treatments for metals, especially for low thickness plates, improving the adhesion between the metallic surface and the paint coating, and increasing the durability of paint systems against corrosion attacks. The tricationic phosphates containing zinc, nickel and manganese are commonly applied on steel. There is much discussion about the replacement of nickel by another element in order to have an environmentally friendly phosphating process. Niobium as a replacement for nickel has been evaluated. The most significant environmental impacts of phosphating processes are related to the presence of nickel and hexavalent chromium used in the process, this last as a passivation treatment. Nickel and hexavalent chromium are harmful to human and environment leading to contamination of water and soil. In the present study phosphate layers containing zinc, manganese and niobium have been evaluated and characterized on galvanized steel, and the results were compared with phosphates containing zinc, manganese and nickel, or a bicationic phosphate layer with zinc and manganese. Although the use of hexavalent chromium is not recommended worldwide, it is still used in processes for sealing the porosity of phosphate layers. This element is carcinogenic and has been associated with various diseases. Due to the passivation characteristics of niobium, this study also evaluated the tricationic bath containing niobium ammonium oxalate as a passivation treatment. The results showed that it could act as a replacement for the hexavalent chromium. The results of the present study showed that formulations containing niobium are potential replacements for hexavalent chromium and similar corrosion protection was obtained for the phosphate containing nickel or that with niobium. The morphology observed by scanning electron microscopy, gravimetric tests, porosity and adhesion evaluation results indicated that the phosphate

  7. Characterization of the dissimilar welding - austenitic stainless steel with filler metal of the nickel alloy

    International Nuclear Information System (INIS)

    Soares, Bruno Amorim; Schvartzman, Monica Maria de Abreu Mendonca; Campos, Wagner Reis da Costa

    2007-01-01

    In elevated temperature environments, austenitic stainless steel and nickel alloy has a superior corrosion resistance due to its high Cr content. Consequently, this alloys is widely used in nuclear reactors components and others plants of energy generation that burn fossil fuel or gas, chemical and petrochemical industries. The object of the present work was to research the welding of AISI 304 austenitic stainless steel using the nickel alloy filler metals, Inconel 625. Gas tungsten arc welding, mechanical and metallographic tests, and compositional analysis of the joint were used. A fundamental investigation was undertaken to characterize fusion boundary microstructure and to better understand the nature and character of boundaries that are associated with cracking in dissimilar welds. The results indicate that the microstructure of the fusion zone has a dendritic structure, inclusions, and precipitated phases containing Ti and Nb are present in the inter-dendritic region. In some parts near to the fusion line it can be seen a band in the weld, probably a eutectic phase with lower melting point than the AISI 304, were the cracking may be beginning by stress corrosion. (author)

  8. Failure of Stainless Steel Welds Due to Microstructural Damage Prevented by In Situ Metallography

    OpenAIRE

    Lopez,Juan Manuel Salgado; Alvarado,María Inés; Hernandez,Hector Vergara; Quiroz,José Trinidad Perez; Olmos,Luis

    2016-01-01

    Abstract In stainless steels, microstructural damage is caused by precipitation of chromium carbides or sigma phase. These microconstituents are detrimental in stainless steel welds because they lead to weld decay. Nevertheless, they are prone to appear in the heat affected zone (HAZ) microstructure of stainless steel welds. This is particularly important for repairs of industrial components made of austenitic stainless steel. Non-destructive metallography can be applied in welding repairs of...

  9. Monitoring of chromium and nickel in biological fluids of stainless steel welders using the flux-cored-wire (FCW) welding method.

    Science.gov (United States)

    Stridsklev, Inger Cecilie; Schaller, Karl-Heinz; Langård, Sverre

    2004-11-01

    This study was undertaken to investigate the exposure to chromium (Cr) and nickel (Ni) in flux-cored wire (FCW) welders welding on stainless steel (SS). Seven FCW welders were monitored for 3 days to 1 workweek, measuring Cr and Ni in air, blood, and urine. The welders were questioned about exposure to Cr and Ni during their whole working careers, with emphasis on the week of monitoring, about the use of personal protective equipment and their smoking habits. The air concentrations were mean 200 microg/m(3) (range 2.4-2,744) for total Cr, 11.3 microg/m(3) (416.7) for Ni during the workdays for the five welders who were monitored with air measurements. The levels of Cr and Ni in biological fluids varied between different workplaces. For Cr in whole blood, plasma, and erythrocytes, the mean levels after work were 1.25 (<0.4-8.3) and 1.68 (<0.2-8.0) and 0.9 (<0.4-7.2) microg/l, respectively. For Ni most of the measurements in whole blood and plasma were below the detection limits, the mean levels after work being 0.84 (<0.8-3.3) and 0.57 microg/l (<0.4-1.7), respectively. Mean levels for Cr and Ni in the urine after work were 3.96 (0.34-40.7) and 2.50 (0.56-5.0) microg/g creatinine, respectively. Correlations between the Cr(VI) levels measured in air and the levels of total Cr in the measured biological fluids were found. The results seem to support the view that monitoring of Cr in the urine may be versatile for indirect monitoring of the Cr(VI) air level in FCW welders. The results seem to suggest that external and internal exposure to Cr and Ni in FCW welders welding SS is low in general.

  10. Release of nickel and chromium ions from orthodontic wires following the use of teeth whitening mouthwashes

    Directory of Open Access Journals (Sweden)

    AmirHossein Mirhashemi

    2018-02-01

    Full Text Available Abstract Background Corrosion resistance is an important requirement for orthodontic appliances. Nickel and chromium may be released from orthodontic wires and can cause allergic reactions and cytotoxicity when patients use various mouthwashes to whiten their teeth. Our study aimed to assess the release of nickel and chromium ions from nickel titanium (NiTi and stainless steel (SS orthodontic wires following the use of four common mouthwashes available on the market. Methods This in vitro, experimental study was conducted on 120 orthodontic appliances for one maxillary quadrant including five brackets, one band and half of the required length of SS, and NiTi wires. The samples were immersed in Oral B, Oral B 3D White Luxe, Listerine, and Listerine Advance White for 1, 6, 24, and 168 h. The samples immersed in distilled water served as the control group. Atomic absorption spectroscopy served to quantify the amount of released ions. Results Nickel ions were released from both wires at all time-points; the highest amount was in Listerine and the lowest in Oral B mouthwashes. The remaining two solutions were in-between this range. The process of release of chromium from the SS wire was the same as that of nickel. However, the release trend in NiTi wires was not uniform. Conclusions Listerine caused the highest release of ions. Listerine Advance White, Oral B 3D White Luxe, and distilled water were the same in terms of ion release. Oral B showed the lowest amount of ion release.

  11. Photo-Electrochemical Effect of Zinc Addition on the Electrochemical Corrosion Potentials of Stainless Steels and Nickel Alloys in High Temperature Water

    International Nuclear Information System (INIS)

    Lee, Yi-Ching; Fong, Clinton; Fang-Chu, Charles; Chang, Ching

    2012-09-01

    Hydrogen water chemistry (HWC) is one of the main mitigating methods for stress corrosion cracking problem of reactor core stainless steel and nickel based alloy components. Zinc is added to minimize the radiation increase associated with HWC. However, the subsequently formed zinc-containing surface oxides may exhibit p-type semiconducting characteristics. Upon the irradiation of Cherenkov and Gamma ray in the reactor core, the ECP of stainless steels and nickel based alloys may shift in the anodic direction, possibly offsetting the beneficial effect of HWC. This study will evaluate the photo-electrochemical effect of Zinc Water Chemistry on SS304 stainless steel and Alloy 182 nickel based weld metal under simulated irradiated BWR water environments with UV illumination. The experimental results reveal that Alloy 182 nickel-based alloy generally possesses n-type semiconductor characteristics in both oxidizing NWC and reducing HWC conditions with zinc addition. Upon UV irradiation, the ECP of Alloy 182 will shift in the cathodic direction. In most conditions, SS304 will also exhibit n-type semiconducting properties. Only under hydrogen water chemistry, a weak p-type property may emerge. Only a slight upward shift in the anodic direction is detected when SS304 is illuminated with UV light. The potential influence of p-type semiconductor of zinc containing surface oxides is weak and the mitigation effect of HWC on the stress corrosion cracking is not adversely affected. (authors)

  12. Endodontic complications of root canal therapy performed by dental students with stainless-steel K-files and nickel-titanium hand files.

    Science.gov (United States)

    Pettiette, M T; Metzger, Z; Phillips, C; Trope, M

    1999-04-01

    Straightening of curved canals is one of the most common procedural errors in endodontic instrumentation. This problem is commonly encountered when dental students perform molar endodontics. The purpose of this study was to compare the effect of the type of instrument used by these students on the extent of straightening and on the incidence of other endodontic procedural errors. Nickel-titanium 0.02 taper hand files were compared with traditional stainless-steel 0.02 taper K-files. Sixty molar teeth comprised of maxillary and mandibular first and second molars were treated by senior dental students. Instrumentation was with either nickel-titanium hand files or stainless-steel K-files. Preoperative and postoperative radiographs of each tooth were taken using an XCP precision instrument with a customized bite block to ensure accurate reproduction of radiographic angulation. The radiographs were scanned and the images stored as TIFF files. By superimposing tracings from the preoperative over the postoperative radiographs, the degree of deviation of the apical third of the root canal filling from the original canal was measured. The presence of other errors, such as strip perforation and instrument breakage, was established by examining the radiographs. In curved canals instrumented by stainless-steel K-files, the average deviation of the apical third of the canals was 14.44 degrees (+/- 10.33 degrees). The deviation was significantly reduced when nickel-titanium hand files were used to an average of 4.39 degrees (+/- 4.53 degrees). The incidence of other procedural errors was also significantly reduced by the use of nickel-titanium hand files.

  13. Hot rolling of chromium - nickel - manganese stainless steel containing nitrogen and boron

    International Nuclear Information System (INIS)

    Khorosh, V.A.; Bulat, S.I.; Mukhina, M.A.; Sorokina, N.A.; Yushchenko, K.A.; Tsentral'nyj Nauchno-Issledovatel'skij Inst. Chernoj Metallurgii, Moscow; AN Ukrainskoj SSR, Kiev. Inst. Ehlektrosvarki)

    1976-01-01

    The strength of stainless steel of the 03Kh2ON16AG6 type increases perceptibly with an increase in the nitrogen content from 0.11 to 0.37%. At the same time, however, its ductility in the region of hot deformation temperatures (red brittleness range of 800 to 1,000 deg C) decreases. Microalloying with boron (0.002 to 0.005% by calculation) permits enhancing the hot ductility to an acceptable level without adversely affecting the working properties. The mechaniusm of boron effect is analyzed. The temperature at which ingots are heated prior to rolling to achieve the desired effect must be sufficiently low. Optimum condition for two stage heating of 6.2-ton ingots are recommeded

  14. DETERMINATION OF METAL IONS RELEASED BY STAINLESS ...

    African Journals Online (AJOL)

    The amounts of cobalt, iron, manganese, nickel and chromium ions released from new and reused stainless steel arch bar used for maxillomandibular fixation was determined in Hank's solutions of different hydrogen and chloride ions concentrations, whole blood serum and phosphate buffered saline (PBS) in vitro, over a ...

  15. Evaluation of Joint Performance on High Nitrogen Stainless Steel Which is Expected to Have Higher Allergy Resistance

    Science.gov (United States)

    Nakano, Kouichi

    Austenitic stainless steel, which includes nickel for stabilizing austenitic structure, is used for various purposes, for example, for structural material, corrosion-resistant material, biomaterial etc. Nickel is set as one of the rare metals and economizing on nickel as the natural resources is required. On the other hand, nickel is one of the metals that cause metallic allergy frequently. Therefore, high nitrogen stainless steel, where nitrogen stabilizes austenitic structure instead of nickel, has been developed in Japan and some of the foreign countries for the above reason. When high nitrogen stainless steel is fused and bonded, dissolved nitrogen is released to the atmospheric area, and some of the material properties will change. In this study, we bonded high nitrogen stainless steel by stud welding process, which is able to bond at short time, and we evaluate joint performance. We have got some interesting results from the other tests and examinations.

  16. Aging between 300 and 450 deg C of wrought martensitic 13-17 wt-%Cr stainless steels

    International Nuclear Information System (INIS)

    Yrieix, B.; Guttmann, M.

    1993-06-01

    Martensitic stainless steels containing 13-17 wt-% Cr, some also containing nickel and some having precipitation hardening additions, have been aged between 300 and 450 deg C for times up to 30 000 h. For all the steels examined, the aging response takes the form of an increase of strength and hardness, correlated with embrittlement. The rate and intensity of aging increase with increasing chromium and molybdenum concentrations. In addition, two steels exhibit some temper embrittlement on long term aging at 400 deg C; such embrittlement of these materials is not expected in service at temperatures up to 300 deg C. A general method of prediction of the mechanical properties of these steels as a function of aging conditions is proposed. (authors). 11 refs., 17 figs., 7 tabs

  17. Development of commercial nitrogen-rich stainless steels

    International Nuclear Information System (INIS)

    Liljas, M.

    1999-01-01

    This paper reviews the development of nitrogen alloyed stainless steels. Nitrogen alloying of austenitic stainless steels started at an early stage and was to a large extent caused by nickel shortage. However, direct technical advantages such as increased strength of the nitrogen alloyed steels made them attractive alternatives to the current steels. It was not until the advent of the AOD (argon oxygen decarburisation) process in the late 1960s that nitrogen alloying could be controlled to such accuracy that it became successful commercially on a broader scale. The paper describes production aspects and how nitrogen addition influences microstructure and the resulting properties of austenitic and duplex stainless steels. For austenitic steels there are several reasons for nitrogen alloying. Apart from increasing strength nitrogen also improves structural stability, work hardening and corrosion resistance. For duplex steels nitrogen also has a decisive effect in controlling the microstructure during thermal cycles such as welding. (orig.)

  18. A comparison of torque expression between stainless steel, titanium molybdenum alloy, and copper nickel titanium wires in metallic self-ligating brackets.

    Science.gov (United States)

    Archambault, Amy; Major, Thomas W; Carey, Jason P; Heo, Giseon; Badawi, Hisham; Major, Paul W

    2010-09-01

    The force moment providing rotation of the tooth around the x-axis (buccal-lingual) is referred to as torque expression in orthodontic literature. Many factors affect torque expression, including the wire material characteristics. This investigation aims to provide an experimental study into and comparison of the torque expression between wire types. With a worm-gear-driven torquing apparatus, wire was torqued while a bracket mounted on a six-axis load cell was engaged. Three 0.019 x 0.0195 inch wire (stainless steel, titanium molybdenum alloy [TMA], copper nickel titanium [CuNiTi]), and three 0.022 inch slot bracket combinations (Damon 3MX, In-Ovation-R, SPEED) were compared. At low twist angles (wires were not statistically significant. At twist angles over 24 degrees, stainless steel wire yielded 1.5 to 2 times the torque expression of TMA and 2.5 to 3 times that of nickel titanium (NiTi). At high angles of torsion (over 40 degrees) with a stiff wire material, loss of linear torque expression sometimes occurred. Stainless steel has the largest torque expression, followed by TMA and then NiTi.

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

    Science.gov (United States)

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

    2017-06-27

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

  20. Biomonitoring of genotoxic exposure among stainless steel welders

    DEFF Research Database (Denmark)

    Knudsen, Lisbeth E.; Boisen, T; Christensen, J M

    1992-01-01

    A biosurvey in the Danish metal industry measured the genotoxic exposure from stainless steel welding. The study comprised measurements of chromosomal aberrations (CA), sister-chromatid exchanges (SCE), unscheduled DNA synthesis (UDS) in peripheral lymphocytes and serum immunoglobulin G. Environm......A biosurvey in the Danish metal industry measured the genotoxic exposure from stainless steel welding. The study comprised measurements of chromosomal aberrations (CA), sister-chromatid exchanges (SCE), unscheduled DNA synthesis (UDS) in peripheral lymphocytes and serum immunoglobulin G....... A higher frequency of chromosomal aberrations, classified as translocations, double minutes, exchanges and rings, was observed in stainless steel welders than in non-welders. SCE was lower in welders working with both MMA and TIG welding than in reference persons. N-Acetoxy-N-acetylaminofluorene (NA...... lymphocytes in exposed persons compared with non-exposed are suggested. MMA welding gave the highest exposure to chromium, an increased number of chromosomal aberrations and a decrease in SCE when compared with TIG welding. Consequently improvements in the occupational practice of stainless steel welding...

  1. Phosphate coating on stainless steel 304 sensitized

    International Nuclear Information System (INIS)

    Cruz V, J. P.; Vite T, J.; Castillo S, M.; Vite T, M.

    2009-01-01

    The stainless steel 304 can be sensitized when welding processes are applied, that causes the precipitation of chromium carbide in the grain limits, being promoted in this way the formation of galvanic cells and consequently the corrosion process. Using a phosphate coating is possible to retard the physiochemical damages that can to happen in the corrosion process. The stainless steel 304 substrate sensitized it is phosphate to base of Zn-Mn, in a immersion cell very hot. During the process was considered optimization values, for the characterization equipment of X-rays diffraction and scanning electron microscopy was used. The XRD technique confirmed the presence of the phases of manganese phosphate, zinc phosphate, as well as the phase of the stainless steel 304. When increasing the temperature from 60 to 90 C in the immersion process a homogeneous coating is obtained. (Author)

  2. Influence of sigma-phase formation on the localized corrosion behavior of a duplex stainless steel

    International Nuclear Information System (INIS)

    Adhe, K.N.; Kain, V.; Madangopal, K.; Gadiyar, H.S.

    1996-01-01

    Because of their austenitic-ferritic microstructures, duplex stainless steels offer a good combination of mechanical and corrosion resistance properties. However, heat treatments can lower the mechanical strength of these stainless steels as well as render them susceptible to intergranular corrosion (IGC) and pitting corrosion. In this study, a low-carbon (0.02%) duplex stainless steel is subjected to various heat treatments at 450 to 950 C for 30 min to 10 h. The heat-treated samples than undergo ASTM IGC and pitting corrosion tests, and the results are correlated with the microstructures obtained after each heat treatment. In the absence of Cr 23 C 6 precipitation, σ-phase precipitates render this duplex stainless steel susceptible to IGC and pitting corrosion. Even submicroscopic σ-phase precipitates are deleterious for IGC resistance. Longer-duration heat treatments (at 750 to 850 C) induce chromium diffusion to replenish the chromium-depleted regions around the σ-phase precipitates and improve IGC resistance; pitting resistance, however, is not fully restored. Various mechanisms of σ-phase formation are discussed to show that regions adjacent to σ-phase are depleted of chromium and molybdenum. The effect of chemical composition (pitting resistance equivalent) on the pitting resistance of various stainless steels is also noted

  3. Liquid Phase Sintering of Highly Alloyed Stainless Steel

    DEFF Research Database (Denmark)

    Mathiesen, Troels

    1996-01-01

    Liquid phase sintering of stainless steel is usually applied to improve corrosion resistance by obtaining a material without an open pore system. The dense structure normally also give a higher strength when compared to conventional sintered steel. Liquid phase sintrering based on addition...... of boride to AISI 316L type steels have previously been studied, but were found to be sensitive to intergranular corrosion due to formation of intermetallic phases rich in chromium and molybdenum. In order to improve this system further, new investigations have focused on the use of higher alloyed stainless...... steel as base material. The stainless base powders were added different amounts and types of boride and sintered in hydrogen at different temperatures and times in a laboratory furnace. During sintering the outlet gas was analyzed and subsequently related to the obtained microstructure. Thermodynamic...

  4. Low temperature grain boundary diffusion of chromium in SUS316 and 316L stainless steels

    International Nuclear Information System (INIS)

    Mizouchi, Masaki; Yamazaki, Yoshihiro; Iijima, Yoshiaki; Arioka, Koji

    2004-01-01

    Grain boundary diffusivity of chromium is SUS316 and 316L stainless steels has been determined in the temperature range between 518 and 1173 K. The magnitudes of the grain boundary diffusivities in four kinds of specimens are in the order of the cold-worked SUS316, the solution-treated SUS316L, the solution-treated SUS316 and the sensitized SUS316. The grain boundary diffusivities in these specimens are remarkably higher than those of previous works. The activation energies for the former are 85-91 kJmol -1 , whereas those for the latter are 151-234 kJmol -1 . (author)

  5. Ductility in a new low nickel stainless steel for reinforced concrete

    Directory of Open Access Journals (Sweden)

    Cobo, A.

    2011-12-01

    Full Text Available This paper discusses the stress-strain curves for a new low nickel stainless steel, a conventional AISI 304 stainless steel and a carbon steel commonly used in reinforced concrete structures. Ductility was studied in terms of ultimate tensile strength (fmax, elastic limit (fy and total elongation at maximum force [ultimate strain; uniform elongation] (εmax. The three materials were assessed with internationally accepted criteria, such as plastic rotational capacity, necking region and the toughness index (total energy absorbed at uniform elongation. The findings were compared to the properties of three types of conventional reinforcing steel: 500SD, 500N and 500H (EC-2.

    En este trabajo se presentan los diagramas tensióndeformación de un nuevo acero inoxidable con bajo contenido en níquel, un inoxidable convencional AISI 304 y un acero al carbono de uso común en estructuras de hormigón armado. Dicha ductilidad se ha estudiado determinando la tensión máxima (fmax, la tensión en el límite elástico (fy y la deformación bajo carga máxima (εmax. Los tres materiales se han evaluado utilizando criterios aceptados internacionalmente, como son el índice p (capacidad de rotación plástica, el índice A* (área plástica de endurecimiento y el índice de tenacidad Id (energía total absorbida en el punto de alargamiento bajo carga máxima, los resultados obtenidos se han comparado con los aceros convencionales de armaduras 500SD, 500N y 500H (EC-2.

  6. Passivation behavior of SUS 304 stainless steel in neutral solutions at elevated temperature

    International Nuclear Information System (INIS)

    Tanno, Kazuo; Kato, Koji; Ohnaka, Noriyuki; Okajima, Yoshiaki; Minato, Akira.

    1981-01-01

    Cyclic voltammograms of SUS 304 stainless steel in various neutral solutions such as Na 2 SO 4 at high temperature were measured, as a successive study to previous report in which effects of temperature and pH on polarization behavior of stainless steel were studied. In this measurement Ag/AgCl reference electrode and platinum counter electrode were used in a static autoclave lined with inconel. Passive films formed in various conditions were analysed by electron diffraction and Auger spectroscopy. Results obtained were compared with anodic behavior of iron, chromium and nickel and with thermodynamical stabilities of their compounds. The main results are summarized as follows. (1) Stainless steel shows such electrochemical behavior as active dissolution, passivation and transpassivation in a deaerated neutral solution at 250 0 C after fully reductive treatment of the specimen. In air-saturated solution, the peak of active dissolution is not observed. In the passive range there are intermediate oxidation and reduction peaks, and it is assumed that dissolved ionic species are oxidized to form oxide of spinel type and higher oxidized state successively at these peaks. (2) Electrochemical behavior of specimens in 0.1 M sulfate, -phosphate and -carbonate solutions are almost the same and rather thick films form in these solutions. On the other hand, specimens are easy to passivate in borate and -nitrate solution, and their passive films are thin. (author)

  7. Corrosion kinetics of 316L stainless steel bipolar plate with chromiumcarbide coating in simulated PEMFC cathodic environment

    Directory of Open Access Journals (Sweden)

    N.B. Huang

    Full Text Available Stainless steel with chromium carbide coating is an ideal candidate for bipolar plates. However, the coating still cannot resist the corrosion of a proton exchange membrane fuel cell (PEMFC environment. In this work, the corrosion kinetics of 316L stainless steel with chromium carbide is investigated in simulated PEMFC cathodic environment by combining electrochemical tests with morphology and microstructure analysis. SEM results reveal that the steel’s surface is completely coated by Cr and chromium carbide but there are pinholes in the coating. After the coated 316L stainless steel is polarized, the diffraction peak of Fe oxide is found. EIS results indicate that the capacitive resistance and the reaction resistance first slowly decrease (2–32 h and then increase. The potentiostatic transient curve declines sharply within 2000 s and then decreases slightly. The pinholes, which exist in the coating, result in pitting corrosion. The corrosion kinetics of the coated 316L stainless steel are modeled and accords the following equation: i0 = 7.6341t−0.5, with the corrosion rate controlled by ion migration in the pinholes. Keywords: PEMFC, Metal bipolar plate, Chromium carbide coating, Corrosion kinetics, Pitting corrosion

  8. Welding of nickel free high nitrogen stainless steel: Microstructure and mechanical properties

    Directory of Open Access Journals (Sweden)

    Raffi Mohammed

    2017-04-01

    Full Text Available High nitrogen stainless steel (HNS is a nickel free austenitic stainless steel that is used as a structural component in defence applications for manufacturing battle tanks as a replacement of the existing armour grade steel owing to its low cost, excellent mechanical properties and better corrosion resistance. Conventional fusion welding causes problems like nitrogen desorption, solidification cracking in weld zone, liquation cracking in heat affected zone, nitrogen induced porosity and poor mechanical properties. The above problems can be overcome by proper selection and procedure of joining process. In the present work, an attempt has been made to correlate the microstructural changes with mechanical properties of fusion and solid state welds of high nitrogen steel. Shielded metal arc welding (SMAW, gas tungsten arc welding (GTAW, electron beam welding (EBW and friction stir welding (FSW processes were used in the present work. Optical microscopy, scanning electron microscopy and electron backscatter diffraction were used to characterize microstructural changes. Hardness, tensile and bend tests were performed to evaluate the mechanical properties of welds. The results of the present investigation established that fully austenitic dendritic structure was found in welds of SMAW. Reverted austenite pools in the martensite matrix in weld zone and unmixed zones near the fusion boundary were observed in GTA welds. Discontinuous ferrite network in austenite matrix was observed in electron beam welds. Fine recrystallized austenite grain structure was observed in the nugget zone of friction stir welds. Improved mechanical properties are obtained in friction stir welds when compared to fusion welds. This is attributed to the refined microstructure consisting of equiaxed and homogenous austenite grains.

  9. Analysis of the passive layer developed on stainless steels implanted with chromium; Analisis de las peliculas pasivas generadas en aceros inoxidables implantados con cromo

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, C. M.; Cristobal, M. J.; Novoa, X. R.; Pena, G.; Perez, M. C.

    2004-07-01

    This work studies the effect of chromium implantation on the development of passive layers generated electrochemically in alkaline medium over two stainless steels. The XPS analyses show that the layers generated on the implanted steels present less thickness together with similar composition compared to the unimplanted steels layers. However, SEM micrographs show that the layers grown on implanted steels present more defects and less adherence that the films on unimplanted steels. These changes together with the results obtained by Cyclic Voltammetry suggest an oxide structure modification, lattice structure or crystallinity state. (Author) 6 refs.

  10. Poly(ophenylenediaminecoaniline/ZnO coated on passivated low nickel stainless steel

    Directory of Open Access Journals (Sweden)

    P. Karthikeyan

    2017-03-01

    Full Text Available Iron and its alloys are broadly used in many applications, which have strengthened the research in corrosion resistance in various neutral and provoking environments. Almost powerful corrosion inhibitors have negative effects on both environment and health. Therefore, there is a need for a primer that provides outstanding adherence and corrosion resistance, and is environmentally safer. The conducting polymer coating on metals was found to offer the anti-corrosion. In this work, the Poly(o-phenylenediamine-co-aniline copolymers (P(Popd-co-Ani and Poly(o-phenylenediamine-co-aniline/ZnO (P(Popd-co-Ani/ZnO composite were synthesized using the electrochemical techniques on borate passivated low nickel stainless steel (LN SS electrodes from lithium perchlorate in acetonitrile solutions containing a fixed concentration of monomer and different concentrations of zinc oxide (ZnO. The structural and morphological analyses of the copolymer and composite coatings were conducted by Fourier transform-infrared spectroscopy (FT-IR, X-ray diffraction (XRD, field emission scanning electron microscopy (FE-SEM, elemental mapping and energy dispersion X-ray spectroscopy (EDX. The surface topography was assessed with using an atomic force microscope (AFM, and the corrosion protection behavior of these copolymer-coated stainless steels was investigated in a 0.5 M H2SO4 solution by the potentiodynamic polarization (Tafel and electrochemical impedance spectroscopy methods. Among the as developed protective copolymer coatings, the P(Popd-co-Ani/ZnO composite exhibited the best corrosion protection.

  11. Ionic nitriding of high chromium martensitic stainless steels

    International Nuclear Information System (INIS)

    Bruhl, S.P; Charadia, R; Vaca, L.S; Cimetta, J

    2008-01-01

    Martensitic stainless steels are used in industrial applications where resistance to corrosion and mechanical resistance are needed simultaneously. These steels are normally used in tempering and annealing condition which gives them hardnesses of 500 and 600 HV (about 54 HRC). Ionic nitriding is an assisted diffusion technique that has recently been successfully applied to harden austenitic stainless steels without reducing their resistance to corrosion. The application with AISI 420 martensitic steels has not given good results yet, because in most cases, it affects their corrosion resistance. This work presents the results of the pulsed nitriding of martensitic steels with a higher chrome content, such as the M340 and M333 Boehler steels and they are compared with the same materials after tempering and annealing, without nitriding. The influence of the variations in the parameters of the process, such as the percentage of active time in the pulsed wave, partial nitrogen pressure, current density and effective tension in the microstructure, hardness and wear and corrosion resistance was studied. The microstructure was studied with an optic microscope; the wear resistance with abrasion tests following ASTM G-65 and corrosion with 100 hour long saline haze tests, in a device built according to ASTM B117. Hardness was found to rise to values of 1000 to 1350 HV in all the steels after ionic nitriding, the modified layers oscillated from 3 to 15 microns. As a result, wear resistance also increased, with differences depending on the microstructure and the thickness of the modified layer. However, corrosion resistance was not good, except in the case of the M333 steel test piece with less hardness and a less thick nitrided layer without a noticeable interphase (au)

  12. Surface electrical properties of stainless steel fibres: An AFM-based study

    International Nuclear Information System (INIS)

    Yin, Jun; D’Haese, Cécile; Nysten, Bernard

    2015-01-01

    Highlights: • Surface electrical conductivity of stainless steel fibre is measured and mapped by CS-AFM. • Surface potential of stainless steel fibre is measured and mapped by KPFM. • Surface electronic properties are governed by the chromium oxide passivation layer. • Electron tunnelling through the passivation layer is the dominant mechanisms for conduction. - Abstract: Atomic force microscopy (AFM) electrical modes were used to study the surface electrical properties of stainless steel fibres. The surface electrical conductivity was studied by current sensing AFM and I–V spectroscopy. Kelvin probe force microscopy was used to measure the surface contact potential. The oxide film, known as passivation layer, covering the fibre surface gives rise to the observation of an apparently semiconducting behaviour. The passivation layer generally exhibits a p-type semiconducting behaviour, which is attributed to the predominant formation of chromium oxide on the surface of the stainless steel fibres. At the nanoscale, different behaviours are observed from points to points, which may be attributed to local variations of the chemical composition and/or thickness of the passivation layer. I–V curves are well fitted with an electron tunnelling model, indicating that electron tunnelling may be the predominant mechanism for electron transport

  13. Nickel titanium springs versus stainless steel springs: A randomized clinical trial of two methods of space closure.

    Science.gov (United States)

    Norman, Noraina Hafizan; Worthington, Helen; Chadwick, Stephen Mark

    2016-09-01

    To compare the clinical performance of nickel titanium (NiTi) versus stainless steel (SS) springs during orthodontic space closure. Two-centre parallel group randomized clinical trial. Orthodontic Department University of Manchester Dental Hospital and Orthodontic Department Countess of Chester Hospital, United Kingdom. Forty orthodontic patients requiring fixed appliance treatment were enrolled, each being randomly allocated into either NiTi (n = 19) or SS groups (n = 21). Study models were constructed at the start of the space closure phase (T0) and following the completion of space closure (T1). The rate of space closure achieved for each patient was calculated by taking an average measurement from the tip of the canine to the mesiobuccal groove on the first permanent molar of each quadrant. The study was terminated early due to time constraints. Only 30 patients completed, 15 in each study group. There was no statistically significant difference between the amounts of space closed (mean difference 0.17 mm (95%CI -0.99 to 1.34; P = 0.76)). The mean rate of space closure for NiTi coil springs was 0.58 mm/4 weeks (SD 0.24) and 0.85 mm/4 weeks (SD 0.36) for the stainless steel springs. There was a statistically significant difference between the two groups (P = 0.024), in favour of the stainless steel springs, when the mean values per patient were compared. Our study shows that stainless steel springs are clinically effective; these springs produce as much space closure as their more expensive rivals, the NiTi springs.

  14. Multilayer graphene for long-term corrosion protection of stainless steel bipolar plates for polymer electrolyte membrane fuel cell

    DEFF Research Database (Denmark)

    Stoot, Adam Carsten; Camilli, Luca; Spiegelhauer, Susie Ann

    2015-01-01

    Abstract Motivated by similar investigations recently published (Pu et al., 2015), we report a comparative corrosion study of three sets of samples relevant as bipolar plates for polymer electrolyte fuel cells: stainless steel, stainless steel with a nickel seed layer (Ni/SS) and stainless steel...

  15. Study of corrosion resistance of AISI 444 ferritic stainless steel for application as a biomaterial

    International Nuclear Information System (INIS)

    Marques, Rogerio Albuquerque

    2014-01-01

    Ferritic stainless steels are ferromagnetic materials. This property does not allow their use in orthopedic prosthesis. Nevertheless, in some specific applications, this characteristic is very useful, such as, for fixing dental and facial prostheses by using magnetic attachments. In this study, the corrosion resistance and cytotoxicity of the AISI 444 ferritic stainless steel, with low nickel content, extra-low interstitial levels (C and N) and Ti and Nb stabilizers, were investigated for magnetic dental attachments application. The ISO 5832-1 (ASTM F-139) austenitic stainless steel and a commercial universal keeper for dental attachment (Neo-magnet System) were evaluated for comparison reasons. The first stainless steel is the most used metallic material for prostheses, and the second one, is a ferromagnetic keeper for dental prostheses (NeoM). In vitro cytotoxicity analysis was performed by the red neutral incorporation method. The results showed that the AISI 444 stainless steel is non cytotoxic. The corrosion resistance was studied by anodic polarization methods and electrochemical impedance spectroscopy (EIS), in a saline phosphate buffered solution (PBS) at 37 °C. The electronic properties of the passive film formed on AISI 444 SS were evaluated by the Mott-Schottky approach. All tested materials showed passivity in the PBS medium and the passive oxide film presented a duplex nature. The highest susceptibility to pitting corrosion was associated to the NeoM SS. This steel was also associated to the highest dopant concentration. The comparatively low levels of chromium (nearly 12.5%) and molybdenum (0.3%) of NeoM relatively to the other studied stainless steels are the probable cause of its lower corrosion resistance. The NeoM chemical composition does not match that of the SUS444 standards. The AISI 444 SS pitting resistance was equivalent to the ISO 5832-1 pointing out that it is a potential candidate for replacement of commercial ferromagnetic alloys used

  16. Effect of triple ion beam irradiation on mechanical properties of high chromium austenitic stainless steel

    International Nuclear Information System (INIS)

    Ioka, Ikuo; Futakawa, Masatoshi; Nanjyo, Yoshiyasu; Kiuchi, Kiyoshi; Anegawa, Takefumi

    2003-01-01

    A high-chromium austenitic stainless steel has been developed for an advanced fuel cladding tube considering waterside corrosion and irradiation embrittlement. The candidate material was irradiated in triple ion (Ni, He, H) beam modes at 573 K up to 50 dpa to simulate irradiation damage by neutron and transmutation product. The change in hardness of the very shallow surface layer of the irradiated specimen was estimated from the slope of load/depth-depth curve which is in direct proportion to the apparent hardness of the specimen. Besides, the Swift's power low constitutive equation (σ=A(ε 0 + ε) n , A: strength coefficient, ε 0 : equivalent strain by cold rolling, n: strain hardening exponent) of the damaged parts was derived from the indentation test combined with an inverse analysis using a finite element method (FEM). For comparison, Type304 stainless steel was investigated as well. Though both Type304SS and candidate material were also hardened by ion irradiation, the increase in apparent hardness of the candidate material was smaller than that of Type304SS. The yield stress and uniform elongation were estimated from the calculated constitutive equation by FEM inverse analysis. The irradiation hardening of the candidate material by irradiation can be expected to be lower than that of Type304SS. (author)

  17. Canal preparation with nickel-titanium or stainless steel instruments without the risk of instrument fracture: preliminary observations

    OpenAIRE

    Ghassan Yared

    2015-01-01

    This report introduces a novel technique that allows a safe and predictable canal negotiation, creation of a glide path and canal preparation with reciprocating nickel-titanium or stainless steel engine-driven instruments in canals where the use of rotary and the newly developed reciprocating instruments is contraindicated. In this novel technique, the instruments are used in reciprocating motion with very small angles. Hand files are not used regardless of the complexity of the canal anatomy...

  18. Study of the polarization for Incoloy 800 and for the stainless stell AISI 304 in mixtures of Iron, Nickel and Chromium Chlorides

    International Nuclear Information System (INIS)

    Travalloni, A.M.; Sathler, L.; Mattos, O.R.

    1985-01-01

    Polarization curves for the Incoloy 800 and for the stainless stell AISI 304 were obtained with static and rotational electrodes. The electrolytes employed showed growing concentrations of mixtures as Iron, Nickel and Chromium Chlorides their proportion being the same as the content of these elements in the respective alloys. The alloys under investigation exhibited a continuous transition behaviour from the passive to the active-passive and to the active conditions. Also, the pH was found the main parameter controlling the anodic behaviour of the alloy. (Author) [pt

  19. Nickel cobaltite nanograss grown around porous carbon nanotube-wrapped stainless steel wire mesh as a flexible electrode for high-performance supercapacitor application

    International Nuclear Information System (INIS)

    Wu, Mao-Sung; Zheng, Zhi-Bin; Lai, Yu-Sheng; Jow, Jiin-Jiang

    2015-01-01

    Graphical abstract: Nickel cobaltite nanograss with bimodal pore size distribution is grown around the carbon nanotube-wrapped stainless steel wire mesh as a high capacitance and stable electrode for high-performance and flexible supercapacitors. - Highlights: • NiCo 2 O 4 nanograss with bimodal pore size distribution is hydrothermally prepared. • Carbon nanotubes (CNTs) wrap around stainless steel (SS) wire mesh as a scaffold. • NiCo 2 O 4 grown on CNT-wrapped SS mesh shows excellent capacitive performance. • Porous CNT layer allows for rapid transport of electron and electrolyte. - Abstract: Nickel cobaltite nanograss with bimodal pore size distribution (small and large mesopores) is grown on various electrode substrates by one-pot hydrothermal synthesis. The small pores (<5 nm) in the nanograss of individual nanorods contribute to large surface area, while the large pore channels (>20 nm) between nanorods offer fast transport paths for electrolyte. Carbon nanotubes (CNTs) with high electrical conductivity wrap around stainless steel (SS) wire mesh by electrophoresis as an electrode scaffold for supporting the nickel cobaltite nanograss. This unique electrode configuration turns out to have great benefits for the development of supercapacitors. The specific capacitance of nickel cobaltite grown around CNT-wrapped SS wire mesh reaches 1223 and 1070 F g −1 at current densities of 1 and 50 A g −1 , respectively. CNT-wrapped SS wire mesh affords porous and conductive networks underneath the nanograss for rapid transport of electron and electrolyte. Flexible CNTs connect the nanorods to mitigate the contact resistance and the volume expansion during cycling test. Thus, this tailored electrode can significantly reduce the ohmic resistance, charge-transfer resistance, and diffusive impedance, leading to high specific capacitance, prominent rate performance, and good cycle-life stability.

  20. Dynamical recrystallization of high purity austenitic stainless steels

    International Nuclear Information System (INIS)

    Gavard, L.

    2001-01-01

    The aim of this work is to optimize the performance of structural materials. The elementary mechanisms (strain hardening and dynamical regeneration, germination and growth of new grains) occurring during the hot working of metals and low pile defect energy alloys have been studied for austenitic stainless steels. In particular, the influence of the main experimental parameters (temperature, deformation velocity, initial grain size, impurities amount, deformation way) on the process of discontinuous dynamical recrystallization has been studied. Alloys with composition equal to those of the industrial stainless steel-304L have been fabricated from ultra-pure iron, chromium and nickel. Tests carried out in hot compression and torsion in order to cover a wide range of deformations, deformation velocities and temperatures for two very different deformation ways have allowed to determine the rheological characteristics (sensitivity to the deformation velocity, apparent activation energy) of materials as well as to characterize their microstructural deformations by optical metallography and electron back-scattered diffraction. The influence of the initial grain size and the influence of the purity of the material on the dynamical recrystallization kinetics have been determined. An analytical model for the determination of the apparent mobility of grain boundaries, a semi-analytical model for the dynamical recrystallization and at last an analytical model for the stationary state of dynamical recrystallization are proposed as well as a new criteria for the transition between the refinement state and the state of grain growth. (O.M.)

  1. X-ray photoelectron spectroscopy investigation of the carburization of 310 stainless steel

    International Nuclear Information System (INIS)

    Tabet, N.; Allam, I.; Yin, R.C.

    2003-01-01

    The surface of 310 stainless steel (310SS) samples was investigated by X-ray photoelectron spectroscopy (XPS) after 500 h cyclic exposure to two carburizing atmospheres: CH 4 (2%)-H 2 (98%) at 800 deg. C, and CH 4 (10%)-H 2 (90%) at 1100 deg. C. The depth distribution of various elements in the surface region was obtained by XPS after successive cycles of argon etching. The microstructure of the alloy was observed by scanning electron microscopy (SEM) and the phases formed during the exposure were analyzed by X-ray diffraction (XRD). The results showed that the major phases that were formed within few micrometer depth during exposure at 800 deg. C include both iron and chromium carbides. (Mn, Cr) oxide was also formed as a result of the reaction with the residual oxygen of the atmosphere. A region of few microns width that was relatively depleted of chromium was formed under the surface as a result of the outwards diffusion of chromium. The exposure to the reducing atmosphere at 1100 deg. C led to the formation of various iron and chromium carbides. No oxide was formed during exposure. In all exposed samples, the surface was Cr enriched while nickel remained buried under the surface region that reacted with the atmosphere

  2. Formation of M23C6-type precipitates and chromium-depleted zones in austenite stainless steel

    International Nuclear Information System (INIS)

    Kaneko, Kenji; Fukunaga, Tatsuya; Yamada, Kazuhiro; Nakada, Nobuo; Kikuchi, Masao; Saghi, Zineb; Barnard, Jon S.; Midgley, Paul A.

    2011-01-01

    Graphical abstract: Precipitate formation during the in situ annealing experiment at 650 o C. -- Formation of M 23 C 6 carbides and chromium-depleted zones in commercially available type 304L stainless steel were investigated by in situ transmission electron microscopy and analytical transmission electron microscopy. It was found that each individual small M 23 C 6 carbide starts to grow with a clear orientation relationship with the matrix, and film-like carbide was subsequently observed at the interfaces with asymmetric Cr-depleted zones. From these experimental results, a model describing the precipitation of M 23 C 6 and the formation of the Cr-depleted zone was proposed.

  3. Computer simulation of sensitization in stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Logan, R W

    1983-12-20

    Stainless steel containers are prime candidates for the containment of nuclear waste in tuff rock. The thermal history of a container involves exposure to temperatures of 500 to 600/sup 0/C when it is welded and possibly filled with molten waste glass, followed by hundreds of years exposure in the 100 to 300/sup 0/C range. The problems of short- and long-term sensitization in stainless steels have been addressed by two computer programs. The TTS program uses classical nucleation and growth theory plus experimental input to predict the onset of precipitation or sensitization under complex thermal histories. The FEMGB program uses quadratic finite-element methods to analyze diffusion processes and chromium depletion during precipitate growth. The results of studies using both programs indicate that sensitization should not be a problem in any of the austenitic stainless steels considered. However, more precise information on the process thermal cycles, especially during welding of the container, is needed. Contributions from dislocation pipe diffusion could promote long-term low-temperature sensitization.

  4. 40 CFR Appendix Xii to Part 266 - Nickel or Chromium-Bearing Materials that may be Processed in Exempt Nickel-Chromium Recovery...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Nickel or Chromium-Bearing Materials that may be Processed in Exempt Nickel-Chromium Recovery Furnaces XII Appendix XII to Part 266... FACILITIES Pt. 266, App. XII Appendix XII to Part 266—Nickel or Chromium-Bearing Materials that may be...

  5. Comparative in vitro biocompatibility of nickel-titanium, pure nickel, pure titanium, and stainless steel: genotoxicity and atomic absorption evaluation.

    Science.gov (United States)

    Assad, M; Lemieux, N; Rivard, C H; Yahia, L H

    1999-01-01

    The genotoxicity level of nickel-titanium (NiTi) was compared to that of its pure constituents, pure nickel (Ni) and pure titanium (Ti) powders, and also to 316L stainless steel (316L SS) as clinical reference material. In order to do so, a dynamic in vitro semiphysiological extraction was performed with all metals using agitation and ISO requirements. Peripheral blood lymphocytes were then cultured in the presence of all material extracts, and their comparative genotoxicity levels were assessed using electron microscopy-in situ end-labeling (EM-ISEL) coupled to immunogold staining. Cellular chromatin exposition to pure Ni and 316L SS demonstrated a significantly stronger gold binding than exposition to NiTi, pure Ti, or the untreated control. In parallel, graphite furnace atomic absorption spectrophotometry (AAS) was also performed on all extraction media. The release of Ni atoms took the following decreasing distribution for the different resulting semiphysiological solutions: pure Ni, 316L SS, NiTi, Ti, and controls. Ti elements were detected after elution of pure titanium only. Both pure titanium and nickel-titanium specimens obtained a relative in vitro biocompatibility. Therefore, this quantitative in vitro study provides optimistic results for the eventual use of nickel-titanium alloys as surgical implant materials.

  6. Influence of PWHT on Toughness of High Chromium and Nickel Containing Martensitic Stainless Steel Weld Metals

    Science.gov (United States)

    Divya, M.; Das, Chitta Ranjan; Mahadevan, S.; Albert, S. K.; Pandian, R.; Kar, Sujoy Kumar; Bhaduri, A. K.; Jayakumar, T.

    2015-06-01

    Commonly used 12.5Cr-5Ni consumable specified for welding of martensitic stainless steels is compared with newly designed 14.5Cr-5Ni consumable in terms of their suitability for repair welding of 410 and 414 stainless steels by gas tungsten arc welding process. Changes in microstructure and austenite evolution were investigated using optical, scanning electron microscopy, X-ray diffraction techniques and Thermo-Calc studies. Microstructure of as-welded 12.5Cr-5Ni weld metal revealed only lath martensite, whereas as-welded 14.5Cr-5Ni weld metal revealed delta-ferrite, retained austenite, and lath martensite. Toughness value of as-welded 12.5Cr-5Ni weld metal is found to be significantly higher (216 J) than that of the 14.5Cr-5Ni weld metal (15 J). The welds were subjected to different PWHTs: one at 923 K (650 °C) for 1, 2, 4 hours (single-stage PWHT) and another one at 923 K (650 °C)/4 h followed by 873 K (600 °C)/2 h or 873 K (600 °C)/4 h (two-stage heat treatment). Hardness and impact toughness of the weld metals were measured for these weld metals and correlated with the microstructure. The study demonstrates the importance of avoiding formation of delta-ferrite in the weld metal.

  7. Design of aging-resitant martensitic stainless steels for pressurized water reactors

    International Nuclear Information System (INIS)

    Cozar, R.; Meyzaud, Y.

    1983-06-01

    With the exception of AISI 403 or 410 grades, the use of high strength martensitic stainless steels in PWR is poorly developped because these materials, like ferritic stainless steels, become embrittled by the precitation of a b.c.c. chromium-rich phase during aging at the operating temperature (290 to 350 0 C). The influence of alloying elements and microstructure on the aging behavior of forged low-carbon martensitic stainless steels containing 12 to 16% Cr, 0 to 2% Mo and 0 to 8% Ni was determined during accelerated aging at 450 0 C. Quantitative relationships were derived between the maximum increase in hardness, the maximum shift in CVN transition temperature and the chemical composition (Cr, Mo, C) and microstructure

  8. Direct quantification of nickel in stainless steels by spectrophotometry

    International Nuclear Information System (INIS)

    Singh, Ritu; Raut, Vaibhavi V.; Jeyakumar, S.; Ramakumar, K.L.

    2007-01-01

    A spectrophotometric method based on the Ni-DMG complex for the quantification of nickel in steel samples without employing any prior separation is reported in the present study. The interfering ions are masked by suitable complexing agents and the method was extended to real samples after validating with BCS and Euro steel standards. (author)

  9. Effects of carbon content and chromium segregation on creep rupture properties of low carbon and medium nitrogen type 316 stainless steel

    International Nuclear Information System (INIS)

    Nakazawa, Takanori; Fujita, Nobuhiro; Kimura, Hidetaka; Komatsu, Hajime; Kotoh, Hiroyuki; Kaguchi, Hitoshi.

    1997-01-01

    The creep rupture properties of type 316 stainless steels containing 0.005-0.022%C and 0.07%N have been investigated at 550degC and 600degC from the aspect of the grain boundary carbide precipitation which was changed with carbon content and chromium segregation. A small amount of carbide precipitated on grain boundaries during creep, because the solubility limit of the carbide is less than 0.005%. The creep rupture ductility of this steel increased with the reduction of carbon content from 0.010% to 0.005% while it decreased with increasing carbon content from 0.010% to 0.020%. Since the amount of grain boundary carbide decreased with reducing carbon content, the increase in ductility was due to the suppression of grain boundary embrittlement caused by the carbide. The creep rupture ductility of this steel was also improved by reducing chromium segregation. This behavior was attributed to the change in carbide morphology from concentrated type to dispersed one, which reduced the grain boundary embrittlement. (author)

  10. Corrosion of 316 stainless steel in high temperature molten Li{sub 2}BeF{sub 4} (FLiBe) salt

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Guiqiu, E-mail: guiqiuzheng@gmail.com; Kelleher, Brian; Cao, Guoping; Anderson, Mark; Allen, Todd; Sridharan, Kumar

    2015-06-15

    In support of structural material development for the fluoride-salt-cooled high-temperature reactor (FHR), corrosion tests of 316 stainless steel were performed in the potential primary coolant, molten Li{sub 2}BeF{sub 4} (FLiBe) at 700 °C for an exposure duration up to 3000 h. Tests were performed in both 316 stainless steel and graphite capsules. Corrosion in both capsule materials occurred by the dissolution of chromium from the stainless steel into the salt which led to the depletion of chromium predominantly along the grain boundaries of the test samples. The samples tested in graphite capsules showed a factor of two greater depth of corrosion attack as measured in terms of chromium depletion, compared to those tested in 316 stainless steel capsules. The samples tested in graphite capsules showed the formation of Cr{sub 7}C{sub 3} particulate phases throughout the depth of the corrosion layer. Samples tested in both types of capsule materials showed the formation of MoSi{sub 2} phase due to increased activity of Mo and Si as a result of Cr depletion, and furthermore corrosion promoted the formation of a α-ferrite phase in the near-surface regions of the 316 stainless steel. Based on the corrosion tests, the corrosion attack depth in FLiBe salt was predicted as 17.1 μm/year and 31.2 μm/year for 316 stainless steel tested in 316 stainless steel and in graphite capsules respectively. It is in an acceptable range compared to the Hastelloy-N corrosion in the Molten Salt Reactor Experiment (MSRE) fuel salt.

  11. Male-mediated spontaneous abortion among spouses of stainless steel welders

    DEFF Research Database (Denmark)

    Hjollund, N H; Bonde, J P; Jensen, T K

    2000-01-01

    Male-mediated spontaneous abortion has never been documented for humans. The welding of stainless steel is associated with the pulmonary absorption of hexavalent chromium, which has genotoxic effects on germ cells in rodents. Clinical and early subclinical spontaneous abortions were examined among...

  12. Current status of stainless steel industry and development of stainless steel

    International Nuclear Information System (INIS)

    Lee, Yong Deuk; Lee, Chan Soo; Kim Kwang Tae

    2000-01-01

    Stainless steel is not only clean and smooth in its surface, but also it is superior in quality in terms of corrosion resistance and strength. So that, it is widely in use in the field of construction, chemical installations, and other industries. Growth of stainless steel industry started since the steel technology was developed for mass production in 1960s. Since then stainless steel industry grew rapidly on account of diversified development in this field and growth rate went up to 5.8% per year comparable to 2.3% of steel growth. The rapid growth is attributed to significant industry developments in Europe and Japan in the years of 1970s and 1980s. In addition to these the expansion of stainless steel industry in Korea and Taiwan. Presently Korea produces about 120,000 tons of stainless steel and occupies about 8% of international market. This means Korea become the second largest single country in world in stainless steel production. Moreover Korea is to reinforce its domestic production line by affiliating production companies, increasing of production capability, and specializing in types of stainless steel. This paper is to describe activity of material development, and types of stainless steel for industry use. (Hong, J. S.)

  13. Influence of Ti, C and N concentration on the intergranular corrosion behaviour of AISI 316Ti and 321 stainless steels

    International Nuclear Information System (INIS)

    Pardo, A.; Merino, M.C.; Coy, A.E.; Viejo, F.; Carboneras, M.; Arrabal, R.

    2007-01-01

    Intergranular corrosion behaviour of 316Ti and 321 austenitic stainless steels has been evaluated in relation to the influence exerted by modification of Ti, C and N concentrations. For this evaluation, electrochemical measurements - double loop electrochemical potentiokinetic reactivation (DL-EPR) - were performed to produce time-temperature-sensitization (TTS) diagrams for tested materials. Transmission (TEM) and scanning electron microscopy (SEM) were used to determine the composition and nature of precipitates. The addition of Ti promotes better intergranular corrosion resistance in stainless steels. The precipitation of titanium carbides reduces the formation of chromium-rich carbides, which occurs at lower concentrations. Also, the reduction of carbon content to below 0.03 wt.% improves sensitization resistance more than does Ti content. The presence of Mo in AISI 316Ti stainless steel reduces chromium-rich carbide precipitation; the reason is that Mo increases the stability of titanium carbides and tends to replace chromium in the formation of carbides and intermetallic compounds, thus reducing the risks of chromium-depletion

  14. Stress corrosion cracking resistance of 22% Cr duplex stainless steel in simulated sour environments

    International Nuclear Information System (INIS)

    Kudo, T.; Tsuge, H.; Moroishi, T.

    1989-01-01

    This paper reports the effect of nickel and nitrogen contents on stress corrosion cracking (SCC) of 22%Cr - 3%Mo-base duplex stainless steel investigated in simulated sour environments with respect to both the base metal and the heat-affected zone (HAZ) of welding. The threshold stress and the critical chloride concentration for SCC were evaluated as a function of the ferrite content (α-content) in the alloy. The threshold stress is highest at the α-content of 40 to 45%, and is lowered with decreasing and increasing the α-content from its value. The alloy whose α-content exceeds 80% at the HAZ has also high susceptibilities to pitting corrosion and intergranular corrosion (ICG). The critical chloride concentration for cracking increases with the decrease in the α-content. Moreover, the contents of chromium, nickel and molybdenum in the α-phase are considered to be an important factor for determining the critical chloride concentration

  15. Study of cyclic oxidation for stainless steels AISI 309 T 253 M A, with low additions of cerium

    International Nuclear Information System (INIS)

    Velazquez F, G.L.; Martinez, M.; Ruiz, A.

    1998-01-01

    It has been detected that the addition of small amounts (<1%) of the so called 'reactive elements' such as Cerium to Fe-Cr alloys that was utilized in oxidating environment at high temperatures improving its resistance to oxidation under isothermal and cyclic conditions. In this work, it was evaluated the behavior under cyclic oxidation conditions for an austenitic stainless steel at chromium-nickel (253MA) with cerium addition, and comparing it with the AISI 310S austenitic stainless steel. The cyclic oxidation essays consist of five cycles by 24 hours each one, following of a cooling in air until ambient temperature from the temperatures of 850, 900 and 950 Centigrade, registering the gain mass of the specimen at end of each cycle. In order to this were prepared samples with dimensions of 20 mm. x 10 mm. x 1 mm. Later to the oxidation essays was evaluated the morphology of the corrosion products layer by scanning electron microscopy. The present phases were identified by X-ray diffraction and by chemical microanalysis by Dispersive energy (EDAX). The results obtained show that the steel with cerium addition, presents a higher adherence and resistance to the spalling noting that the cerium promotes the casting anchor of the oxides layer to matrix and by reducing the grain size of the layer improving its plasticity. Additionally the cerium promotes the preferential oxidation of the forming elements of protective layers like the chromium. (Author)

  16. Performance of high molybdenum superaustenitic stainless steel welds in harsh chloride environments

    International Nuclear Information System (INIS)

    Stenvall, P.; Liljas, M.; Wallen, B.

    1996-01-01

    Superaustenitic steels are normally welded with nickel-based alloys as filler materials. To clarify the understanding of weld behavior in superaustenitic stainless steels this paper presents the development history of 6Mo and 7Mo steels, and results of laboratory tests and field tests on welds of UNS S31254 (6Mo) and UNS S32654 (7 Mo) in different types of chloride containing environments. The laboratory tests consisted of the well known ferric chloride test (ASTM G 48 Method A). Shielded metal arc welds, gas tungsten arc welds and submerged arc welds in both grades were tested. The critical pitting temperatures were determined and the locations of the attack were noted. Some specimens were sectioned at the position of the attack followed by studies using light optical microscopy. The critical pitting temperatures of the welds in S31254 and S32654 were at normal levels for both grades, i.e., 40--50 C for S31254 and 60--75 C for S32654. The locations of the attack differed depending on the welding process. In shielded metal arc welds the attack was mostly located in the weld metal. In gas tungsten arc welds the attack was predominantly located next to the fusion line. The field tests showed that the behavior of welds and parent metal of superaustenitic stainless steels, as well as of nickel-based alloys, is much dependent on the corrosive environment. In oxidizing chloride solutions, similar results to those of the ferric chloride test, are observed. However, crevice corrosion in the parent material is at a greater risk than pitting corrosion in the welds. In very oxidizing solutions of low chloride concentrations, welds made of nickel-based fillers may corrode faster than the stainless steel base metal due to transpassive uniform corrosion. The opposite situation exists when active uniform corrosion prevails, i.e., welds made of nickel-based fillers corrode less than the stainless steel parent material

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

    Energy Technology Data Exchange (ETDEWEB)

    Nikitasari, Arini, E-mail: arini-nikitasari@yahoo.com; Mabruri, Efendi, E-mail: efendi-lipi@yahoo.com [Research Center for Metallurgy and Materials, Indonesian Institute of Sciences (470 Building, Puspiptek, Serpong, Indonesia 15313) (Indonesia)

    2016-04-19

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

  18. The relation between the amount of dissolved water and metals dissolved from stainless steel or aluminum plate in safflower oil

    International Nuclear Information System (INIS)

    Takasago, Masahisa; Takaoka, Kyo

    1986-01-01

    The amount of water dissolved in safflower oil at the frying temperature (180 deg C) was 518 ∼ 1012 ppm, allowing water to drop continuously (0.035 g/2 min) into the oil for 1 ∼ 3 h. When the oil was heated with metal plates under the same conditions, the amount of dissolved water in the oil increased more than in the absence of the metal plates. In case of stainless steel, the amount was 1.26 to 1.33 times, and with aluminum plates, 1.06 to 1.13 times the amount without plates. When these metal plates were heated with the oil under the above conditions, the water dissolved the metal of the plates into the oil. In case of stainless steel, iron dissolved from 0.17 to 0.77 ppm, nickel, 0.04 ppm and chromium, from 0.02 to 0.03 ppm. Similarly, the amount of aluminum dissolved from the aluminum plate was from 0.10 to 0.45 ppm. (author)

  19. Profiling stainless steel welding processes to reduce fume emissions, hexavalent chromium emissions and operating costs in the workplace.

    Science.gov (United States)

    Keane, Michael; Siert, Arlen; Stone, Samuel; Chen, Bean T

    2016-01-01

    Nine gas metal arc welding (GMAW) processes for stainless steel were assessed for fume generation rates, fume generation rates per g of electrode consumed, and emission rates for hexavalent chromium (Cr(6+)). Elemental manganese, nickel, chromium, iron emissions per unit length of weld, and labor plus consumables costs were similarly measured. Flux-cored arc welding and shielded metal arc (SMAW) processes were also studied. The objective was to identify the best welding processes for reducing workplace exposures, and estimate costs for all processes. Using a conical chamber, fumes were collected, weighed, recovered, and analyzed by inductively coupled atomic emission spectroscopy for metals, and by ion chromatography for Cr(6+). GMAW processes used were Surface Tension Transfer, Regulated Metal Deposition, Cold Metal Transfer, short-circuit, axial spray, and pulsed spray modes. Flux-cored welding used gas shielding; SMAW used E308 rods. Costs were estimated as dollars per m length of a ¼ in (6.3 mm) thick horizontal butt weld; equipment costs were estimated as ratios of new equipment costs to a 250 ampere capacity SMAW welding machine. Results indicate a broad range of fume emission factors for the processes studied. Fume emission rates per g of electrode were lowest for GMAW processes such as pulsed-spray mode (0.2 mg/g), and highest for SMAW (8 mg fume/g electrode). Emission rates of Cr(6+) ranged from 50-7800 µg/min, and Cr(6+) generation rates per g electrode ranged from 1-270 µg/g. Elemental Cr generation rates spanned 13-330 µg/g. Manganese emission rates ranged from 50-300 µg/g. Nickel emission rates ranged from 4-140 µg/g. Labor and consumables costs ranged from $3.15 (GMAW pulsed spray) to $7.40 (SMAW) per meter of finished weld, and were measured or estimated for all 11 processes tested. Equipment costs for some processes may be as much as five times the cost of a typical SMAW welding machine. The results show that all of the GMAW processes in this

  20. Analysis of features of stainless steels in dissimilar welded joints in chloride inducted corrosion

    Science.gov (United States)

    Topolska, S.; Łabanowski, J.

    2017-08-01

    Stainless steels of femtic-austenitic microstructure that means the duplex Cr-Ni-Mo steels, in comparison with austenitic steel includes less expensive nickel and has much better mechanical properties with good formability and corrosion resistance, even in environments containing chloride ions. Similar share of high chromium ferrite and austenite, which is characterized by high ductility, determines that the duplex steels have good crack resistance at temperatures up to approximately -40°C. The steels containing approximately 22% Cr, 5% Ni, 3% Mo and 0.2% N crystallizes as a solid solution δ, partially transforming from the temperature of about 1200°C to 850°C into the phase α. The stable structure of considered steels, at temperatures above 850°C, is ferrite, and at lower temperatures the mixture of phase γ+α +σ. The two-phase structure α+γ the duplex steel obtains after hyperquenching at the temperature of stability of the mixture of α+γ phases, and the share of the phases depends on the hyper quenching attributes. Hyperquenching in water, with a temperature close to 1200°C, ensures the instance in the microstructure of the steel a large share of ferrite and a small share of the high chromium austenite. This causes the increase of strength properties and reducing the plasticity of the steel and its resistance ability to cracking and corrosion. Slower cooling from the mentioned temperature, for example in the air, enables the partial transformation of the a phase into the γ one (α → γ) and increasing the share of austenite in the steel structure. It leads to improvement of plasticity properties. In the paper are presented the results of investigations of heteronymous welded joints of duplex steel and austenitic one. The results include the relation between the chemical composition of steels and their weldability.

  1. A compact and low cost laser induced breakdown spectroscopic system: Application for simultaneous determination of chromium and nickel in steel using multivariate calibration

    Energy Technology Data Exchange (ETDEWEB)

    Barbieri Gonzaga, Fabiano [Chemical Metrology Division, National Institute of Metrology, Quality and Technology, Av. N. S. das Gracas, 50, Xerem, 25250-020, Duque de Caxias, RJ (Brazil); Pasquini, Celio, E-mail: pasquini@iqm.unicamp.br [Institute of Chemistry, State University of Campinas, POB 6154, 13083-970, Campinas, SP (Brazil)

    2012-03-15

    This work describes a compact and low cost analyzer for laser induced breakdown spectroscopy (LIBS) based on a diode pumped passively Q-switched Nd:LSB microchip laser and a conventional Czerny-Turner spectrograph (spectral range from about 250 to 390 nm) containing a non-intensified, non-gated and non-cooled 1024 pixel linear sensor array. The new LIBS instrument was applied for analyzing steel samples containing chromium and nickel in the concentration range from about 5 to 26% w/w (certified reference materials), integrating the emitted radiation for 40 s under continuous application of laser pulses at 2 kHz for each acquired spectrum (integration of about 80,000 plasmas). The emission data from about 356 to 362 nm and 340 to 354 nm were employed for the construction of two Partial Least Squares (PLS) calibration models for determination of chromium and nickel, respectively. The average relative errors of prediction of chromium and nickel concentrations were 3.7 and 6.7%, respectively, which are similar to or lower than those obtained using higher cost LIBS analyzers. The results have shown that multivariate calibration can help to overcome the decreasing instrumental performance associated with the low cost equipment. - Highlights: Black-Right-Pointing-Pointer Low cost laser induced breakdown spectroscopy instrumentation. Black-Right-Pointing-Pointer Microchip laser based LIBS system. Black-Right-Pointing-Pointer Standard non-intensified, non-gated, non-cooled detector for LIBS system. Black-Right-Pointing-Pointer Improvement of results from a low cost LIBS system using multivariate calibration. Black-Right-Pointing-Pointer Cr and Ni determination in steel by a low cost LIBS system.

  2. Attenuation capability of low activation-modified high manganese austenitic stainless steel for fusion reactor system

    Energy Technology Data Exchange (ETDEWEB)

    Eissa, M.M. [Steel Technology Department, Central Metallurgical Research and Development Institute (CMRDI), Helwan (Egypt); El-kameesy, S.U.; El-Fiki, S.A. [Physics Department, Faculty of Science, Ain Shams University, Cairo (Egypt); Ghali, S.N. [Steel Technology Department, Central Metallurgical Research and Development Institute (CMRDI), Helwan (Egypt); El Shazly, R.M. [Physics Department, Faculty of Science, Al-Azhar University, Cairo (Egypt); Saeed, Aly, E-mail: aly_8h@yahoo.com [Nuclear Power station Department, Faculty of Engineering, Egyptian-Russian University, Cairo (Egypt)

    2016-11-15

    Highlights: • Improvement stainless steel alloys to be used in fusion reactors. • Structural, mechanical, attenuation properties of investigated alloys were studied. • Good agreement between experimental and calculated results has been achieved. • The developed alloys could be considered as candidate materials for fusion reactors. - Abstract: Low nickel-high manganese austenitic stainless steel alloys, SSMn9Ni and SSMn10Ni, were developed to use as a shielding material in fusion reactor system. A standard austenitic stainless steel SS316L was prepared and studied as a reference sample. The microstructure properties of the present stainless steel alloys were investigated using Schaeffler diagram, optical microscopy, and X-ray diffraction pattern. Mainly, an austenite phase was observed for the prepared stainless steel alloys. Additionally, a small ferrite phase was observed in SS316L and SSMn10Ni samples. The mechanical properties of the prepared alloys were studied using Vickers hardness and tensile tests at room temperature. The studied manganese stainless steel alloys showed higher hardness, yield strength, and ultimate tensile strength than SS316L. On the other hand, the manganese stainless steel elongation had relatively lower values than the standard SS316L. The removal cross section for both slow and total slow (primary and those slowed down in sample) neutrons were carried out using {sup 241}Am-Be neutron source. Gamma ray attenuation parameters were carried out for different gamma ray energy lines which emitted from {sup 60}Co and {sup 232}Th radioactive sources. The developed manganese stainless steel alloys had a higher total slow removal cross section than SS316L. While the slow neutron and gamma rays were nearly the same for all studied stainless steel alloys. From the obtained results, the developed manganese stainless steel alloys could be considered as candidate materials for fusion reactor system with low activation based on the short life

  3. Soft tissue response to a new austenitic stainless steel with a negligible nickel content.

    Science.gov (United States)

    Tschon, M; Fini, M; Giavaresi, G; Borsari, V; Lenger, H; Bernauer, J; Chiesa, R; Cigada, A; Chiusoli, L; Giardino, R

    2005-10-01

    This study evaluates the soft tissue response to a new austenitic stainless steel with a low nickel content (P558) in comparison with a conventional stainless steel (SSt)and a titanium alloy (Ti6Al4V). Previous findings showed its in vitro biocompatibility by culturing P558 with healthy and osteoporotic osteoblasts and its in vivo effectiveness as bone implant material. Regarding its use as a material in osteosynthesis,P558 biocompatibility when implanted in soft tissues, as subcutis and muscle, was assessed. Disks and rods of these metals were implanted in rat subcutis and in rabbit muscle, respectively. Four and twelve weeks post surgery implants with surrounding tissue were retrieved for histologic and histomorphometric analysis: fibrous capsule thickness and new vessel formation were measured. Around all implanted materials, light microscopy highlighted a reactive and fibrous capsule formation coupled with ongoing neoangiogenesis both in rats and in rabbits. Histomorphometric measurements revealed a stronger inflammatory response,in terms of capsule thickness,surrounding SSt implants (9.8% Ni content) both in rat subcutis and in rabbit muscle independently of shape and site of implantation. A progressive decrease in capsule thickness around P558 (implantation. However,in the light of the previous and present studies, P558 is a good material, instead of titanium alloys, in orthopedic research.

  4. Weldability of Stainless Steels

    International Nuclear Information System (INIS)

    Saida, Kazuyoshi

    2010-01-01

    It gives an outline of metallographic properties of welding zone of stainless steels, generation and mechanisms of welding crack and decreasing of corrosion resistance of welding zone. It consists of seven chapters such as introduction, some kinds of stainless steels and properties, metallographic properties of welding zone, weld crack, toughness of welding zone, corrosion resistance and summary. The solidification modes of stainless steels, each solidification mode on the cross section of Fe-Cr-Ni alloy phase diagram, each solidification mode of weld stainless steels metal by electron beam welding, segregation state of alloy elements at each solidification mode, Schaeffler diagram, Delong diagram, effects of (P + S) mass content in % and Cr/Ni equivalent on solidification cracking of weld stainless steels metal, solidification crack susceptibility of weld high purity stainless steels metal, effects of trace impurity elements on solidification crack susceptibility of weld high purity stainless steels metal, ductile fracture susceptibility of weld austenitic stainless steels metal, effects of H2 and ferrite content on generation of crack of weld 25Cr-5N duplex stainless steels, effects of O and N content on toughness of weld SUS 447J1 metals, effect of ferrite content on aging toughness of weld austenitic stainless steel metal, corrosion morphology of welding zone of stainless steels, generation mechanism of knife line attack phenomenon, and corrosion potential of some kinds of metals in seawater at room temperature are illustrated. (S.Y.)

  5. The electrochemical aspect of the corrosion of austenitic stainless steels, in nitric acid and in the presence of hexavalent chromium (1961)

    International Nuclear Information System (INIS)

    Coriou, H.; Hure, J.; Plante, G.

    1961-01-01

    The corrosion of austenitic stainless steels in boiling nitric acid markedly increases when the medium contains hexavalent chromium ions. Because of several redox phenomena, the potential of the steel generally changes in course of time. Measurements show a relation between the weight loss and the potential of specimens. Additions of Mn(VII) and Ce(IV) are compared with that of Cr(VI), and show that the relation is a general one. The attack cf the metal in oxidizing media is largely intergranular, leading to exfoliation of the grains, although the steel studied is not sensitive to the classical Huey and Strauss tests. Also even in the absence of any other oxidizing reaction, the current density observed when the steel is anodically polarized under potentiostatic conditions does not correspond to the actual weight loss of the metal. (authors) [fr

  6. A comparison of cytotoxicity and oxidative stress from welding fumes generated with a new nickel-, copper-based consumable versus mild and stainless steel-based welding in RAW 264.7 mouse macrophages.

    Science.gov (United States)

    Badding, Melissa A; Fix, Natalie R; Antonini, James M; Leonard, Stephen S

    2014-01-01

    Welding processes that generate fumes containing toxic metals, such as hexavalent chromium (Cr(VI)), manganese (Mn), and nickel (Ni), have been implicated in lung injury, inflammation, and lung tumor promotion in animal models. While federal regulations have reduced permissible worker exposure limits to Cr(VI), this is not always practical considering that welders may work in confined spaces and exhaust ventilation may be ineffective. Thus, there has been a recent initiative to minimize the potentially hazardous components in welding materials by developing new consumables containing much less Cr(VI) and Mn. A new nickel (Ni) and copper (Cu)-based material (Ni-Cu WF) is being suggested as a safer alternative to stainless steel consumables; however, its adverse cellular effects have not been studied. This study compared the cytotoxic effects of the newly developed Ni-Cu WF with two well-characterized welding fumes, collected from gas metal arc welding using mild steel (GMA-MS) or stainless steel (GMA-SS) electrodes. RAW 264.7 mouse macrophages were exposed to the three welding fumes at two doses (50 µg/ml and 250 µg/ml) for up to 24 hours. Cell viability, reactive oxygen species (ROS) production, phagocytic function, and cytokine production were examined. The GMA-MS and GMA-SS samples were found to be more reactive in terms of ROS production compared to the Ni-Cu WF. However, the fumes from this new material were more cytotoxic, inducing cell death and mitochondrial dysfunction at a lower dose. Additionally, pre-treatment with Ni-Cu WF particles impaired the ability of cells to phagocytize E. coli, suggesting macrophage dysfunction. Thus, the toxic cellular responses to welding fumes are largely due to the metal composition. The results also suggest that reducing Cr(VI) and Mn in the generated fume by increasing the concentration of other metals (e.g., Ni, Cu) may not necessarily improve welder safety.

  7. Influence of delta ferrite on corrosion susceptibility of AISI 304 austenitic stainless steel

    Directory of Open Access Journals (Sweden)

    Lawrence O. Osoba

    2016-12-01

    Full Text Available In the current study, the influence of delta (δ ferrite on the corrosion susceptibility of AISI 304 austenitic stainless steel was evaluated in 1Molar concentration of sulphuric acid (H2SO4 and 1Molar concentration of sodium chloride (NaCl. The study was performed at ambient temperature using electrochemical technique—Tafel plots to evaluate the corrosive tendencies of the austenitic stainless steel sample. The as-received (stainless steel specimen and 60% cold-worked (stainless steel specimens were isothermally annealed at 1,100°C for 2 h and 1 h, respectively, and quenched in water. The results obtained show that the heat-treated specimen and the 60% cold-worked plus heat-treated specimen exhibited higher corrosion susceptibility than the as-received specimen, which invariably contained the highest fraction of δ ferrite particles. The finding shows that the presence of δ ferrite, in which chromium (Cr, the main corrosion inhibitor segregates, does not degrade and or reduces the resistance to aqueous corrosion of the austenitic stainless steel material.

  8. Occupational asthma due to manual metal-arc welding of special stainless steels.

    Science.gov (United States)

    Hannu, T; Piipari, R; Kasurinen, H; Keskinen, H; Tuppurainen, M; Tuomi, T

    2005-10-01

    Occupational asthma (OA) can be induced by fumes of manual metal-arc welding on stainless steel. In recent years, the use of special stainless steels (SSS) with high chromium content has increased. This study presents two cases of OA caused by manual metal-arc welding on SSS. In both cases, the diagnosis of OA was based on respiratory symptoms, occupational exposure and positive findings in the specific challenge tests. In the first case, a 46-yr-old welder had experienced severe dyspnoea while welding SSS (SMO steel), but not in other situations. Challenge tests with both mild steel and stainless steel using a common electrode were negative. Welding SSS with a special electrode caused a delayed 37% drop in forced expiratory volume in one second (FEV1). In the second case, a 34-yr-old male had started to experience dyspnoea during the past few years, while welding especially SSS (Duplex steel). The workplace peak expiratory flow monitoring was suggestive of OA. Challenge tests with both mild steel and stainless steel using a common electrode did not cause bronchial obstruction. Welding SSS with a special electrode caused a delayed 31% drop in FEV1. In conclusion, exposure to manual metal-arc welding fumes of special stainless steel should be considered as a new cause of occupational asthma.

  9. Failure of Stainless Steel Welds Due to Microstructural Damage Prevented by In Situ Metallography

    Directory of Open Access Journals (Sweden)

    Juan Manuel Salgado Lopez

    Full Text Available Abstract In stainless steels, microstructural damage is caused by precipitation of chromium carbides or sigma phase. These microconstituents are detrimental in stainless steel welds because they lead to weld decay. Nevertheless, they are prone to appear in the heat affected zone (HAZ microstructure of stainless steel welds. This is particularly important for repairs of industrial components made of austenitic stainless steel. Non-destructive metallography can be applied in welding repairs of AISI 304 stainless steel components where it is difficult to ensure that no detrimental phase is present in the HAZ microstructure. The need of microstructural inspection in repairs of AISI 304 is caused because it is not possible to manufacture coupons for destructive metallography, with which the microstructure can be analyzed. In this work, it is proposed to apply in situ metallography as non-destructive testing in order to identify microstructural damage in the microstructure of AISI 304 stainless steel welds. The results of this study showed that the external surface micrographs of the weldment are representative of HAZ microstructure of the stainless steel component; because they show the presence of precipitated metallic carbides in the grain boundaries or sigma phase in the microstructure of the HAZ.

  10. Corrosion and Nanomechanical Behaviors of 16.3Cr-0.22N-0.43C-1.73Mo Martensitic Stainless Steel

    International Nuclear Information System (INIS)

    Ghosh, Rahul; Krishna, S. Chenna; Venugopal, A.; Narayanan, P. Ramesh; Jha, Abhay K.; Ramkumar, P.; Venkitakrishnan, P. V.

    2016-01-01

    The effect of nitrogen on the electrochemical corrosion and nanomechanical behaviors of martensitic stainless steel was examined using potentiodynamic polarization and nanoindentation test methods. The results indicate that partial replacement of carbon with nitrogen effectively improved the passivation and pitting corrosion resistance of conventional high-carbon and high- chromium martensitic steels. Post-test observation of the samples after a potentiodynamic test revealed a severe pitting attacks in conventional martensitic steel compared with nitrogen- containing martensitic stainless steel. This was shown to be due to (i) microstructural refinement results in retaining a high-chromium content in the matrix, and (ii) the presence of reversed austenite formed during the tempering process. Since nitrogen addition also resulted in the formation of a Cr_2N phase as a process of secondary hardening, the hardness of the nitrogen- containing steel is slightly higher than the conventional martensitic stainless steel under tempered conditions, even though the carbon content is lowered. The added nitrogen also improved the wear resistance of the steel as the critical load (Lc2) is less, along with a lower scratch friction coefficient (SFC) when compared to conventional martensitic stainless steel such as AISI 440C.

  11. Corrosion and Nanomechanical Behaviors of 16.3Cr-0.22N-0.43C-1.73Mo Martensitic Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Rahul; Krishna, S. Chenna; Venugopal, A.; Narayanan, P. Ramesh; Jha, Abhay K.; Ramkumar, P.; Venkitakrishnan, P. V. [Vikram Sarabhai Space Centre (ISRO), Kerala (India)

    2016-12-15

    The effect of nitrogen on the electrochemical corrosion and nanomechanical behaviors of martensitic stainless steel was examined using potentiodynamic polarization and nanoindentation test methods. The results indicate that partial replacement of carbon with nitrogen effectively improved the passivation and pitting corrosion resistance of conventional high-carbon and high- chromium martensitic steels. Post-test observation of the samples after a potentiodynamic test revealed a severe pitting attacks in conventional martensitic steel compared with nitrogen- containing martensitic stainless steel. This was shown to be due to (i) microstructural refinement results in retaining a high-chromium content in the matrix, and (ii) the presence of reversed austenite formed during the tempering process. Since nitrogen addition also resulted in the formation of a Cr{sub 2}N phase as a process of secondary hardening, the hardness of the nitrogen- containing steel is slightly higher than the conventional martensitic stainless steel under tempered conditions, even though the carbon content is lowered. The added nitrogen also improved the wear resistance of the steel as the critical load (Lc2) is less, along with a lower scratch friction coefficient (SFC) when compared to conventional martensitic stainless steel such as AISI 440C.

  12. Development of low-chromium, chromium-tungsten steels for fusion

    International Nuclear Information System (INIS)

    Klueh, R.L.; Alexander, D.J.; Kenik, E.A.

    1995-01-01

    High-chromium (9-12% Cr) Cr-Mo and Cr-W ferritic steels are favored as candidates for fusion applications. In early work to develop reduced-activation steels, an Fe-2.25Cr-2W-0.25V-0.1C steel (designated 2.25Cr-2WV) had better strength than an Fe-9Cr-2W-0.25V-0.07Ta-0.1C (9Cr-2WVTa) steel (compositions are in weight percent). However, the 2.25Cr-2WV had poor impact properties, as determined by the ductile-brittle transition temperature and upper-shelf energy of subsize Charpy impact specimens. Because low-chromium steels have some advantages over high-chromium steels, a program to develop low-chromium steels is in progress. Microstructural analysis indicated that the reason for the inferior impact toughness of the 2.25Cr-2WV was the granular bainite obtained when the steel was normalized. Properties can be improved by developing an acicular bainite microstructure by increasing the cooling rate after austenitization. Alternatively, acicular bainite can be promoted by increasing the hardenability. Hardenability was changed by adding small amounts of boron and additional chromium to the 2.25Cr-2WV composition. A combination of B, Cr, and Ta additions resulted in low-chromium reduced-activation steels with mechanical properties comparable to those of 9Cr-2WVTa. (orig.)

  13. Dependence of corrosion properties of AISI 304L stainless steel on the austenite grain size

    Energy Technology Data Exchange (ETDEWEB)

    Sabooni, Soheil; Rashtchi, Hamed; Eslami, Abdoulmajid; Karimzadeh, Fathallah; Enayati, Mohammad Hossein; Raeissi, Keyvan; Imani, Reihane Faghih [Isfahan Univ. of Technology, Isfahan (Iran, Islamic Republic of). Dept. of Materials Engineering; Ngan, Alfonso Hing Wan [The Univ. of Hong Kong (China). Dept. of Mechanical Engineering

    2017-07-15

    The corrosion resistance of austenitic stainless steels is known to be hampered by the loss of chromium available for passive surface layer formation as a result of chromium carbide precipitation at austenite grain boundaries during annealing treatments. Although high-temperature annealing can promote carbide dissolution leading to better corrosion resistance, grain coarsening also results, which would lead to poorer mechanical properties. Processing methods to achieve both good corrosion resistance and mechanical properties are thus highly desirable for austenitic stainless steels. In the present study, we show that the corrosion resistance of AISI 304L stainless steel can be improved by grain refinement into the ultrafine-grained regime. Specifically, samples with different austenite grain sizes in the range of 0.65-12 μm were studied by potentiodynamic polarization and electrochemical impedance spectroscopy tests in a 3.5 wt.% NaCl solution. All samples showed a typical passive behavior with similar corrosion potential, but the corrosion current density decreased significantly with decreasing grain size. The results show that the sample with the finest grain size had the best corrosion resistance due to a higher resistance of the passive layer to pitting attacks. This study indicates that grain refinement which improves mechanical properties can also significantly improve the corrosion resistance of AISI 304L stainless steel.

  14. Relation between the amount of dissolved water and metals dissolved from stainless steel or aluminum plate in safflower oil

    Energy Technology Data Exchange (ETDEWEB)

    Takasago, Masahisa; Takaoka, Kyo

    1986-12-01

    The amount of water dissolved in safflower oil at the frying temperature (180 deg C) was 518 -- 1012 ppM, allowing water to drop continuously (0.035 g/2 min) into the oil for 1 -- 3 h. When the oil was heated with metal plates under the same conditions, the amount of dissolved water in the oil increased more than in the absence of the metal plates. In case of stainless steel, the amount was 1.26 to 1.33 times, and with aluminum plates, 1.06 to 1.13 times the amount without plates. When these metal plates were heated with the oil under the above conditions, the water dissolved the metal of the plates into the oil. In case of stainless steel, iron dissolved from 0.17 to 0.77 ppM, nickel, 0.04 ppM and chromium, from 0.02 to 0.03 ppM. Similarly, the amount of aluminum dissolved from the aluminum plate was from 0.10 to 0.45 ppM.

  15. Effect of metal surface composition on deposition behavior of stainless steel component dissolved in liquid sodium

    International Nuclear Information System (INIS)

    Yokota, Norikatsu; Shimoyashiki, Shigehiro

    1988-01-01

    Deposition behavior of corrosion products has been investigated to clarify the effect of metal surface composition on the deposition process in liquid sodium. For the study a sodium loop made of Type 304 stainless steel was employed. Deposition test pieces, which were Type 304 stainless steel, iron, nickel or Inconel 718, were immersed in the sodium pool of the test pot. Corrosion test pieces, which were Type 304 stainless steel, 50 at% Fe-50 at%Mn and Inconel 718, were set in a heater pin assembly along the axial direction of the heater pin surface. Sodium temperatures at the outlet and inlet of the heater pin assembly were controlled at 943 and 833 K, respectively. Sodium was purified at a cold trap temperature of 393 K and the deposition test was carried out for 4.3 x 10 2 - 2.9 x 10 4 ks. Several crystallized particles were observed on the surface of the deposition test pieces. The particles had compositions and crystal structures which depended on both the composition of deposition test pieces and the concentration of iron and manganese in sodium. Only iron-rich particles having a polyhedral shape deposited on the iron surface. Two types of particles, iron-rich α-phase and γ-phase with nearly the same composition as stainless steel, were deposited on Type 304 stainless steel. A Ni-Mn alloy was deposited on the nickel surface in the case of a higher concentration of manganese in sodium. On the other hand, for a lower manganese concentration, a Fe-Ni alloy was precipitated on the nickel surface. Particles deposited on nickel had a γ-phase crystal structure similar to the deposition test piece of nickel. Hence, the deposition process can be explained as follows: Corrosion products in liquid sodium were deposited on the metal surface by forming a metal alloy selectively with elements of the metal surface. (author)

  16. Localized corrosion of high alloyed austenitic stainless steels

    International Nuclear Information System (INIS)

    Morach, R.; Schmuki, P.; Boehni, H.

    1992-01-01

    The susceptibility of several high alloyed stainless steels against localized corrosion was investigated by traditional potentiostatic and -kinetic methods and the current transient technique. Different test cells, proposed in literature, were evaluated for use in testing of plate materials. The AVESTA-cell showed to be not useful for potentiokinetic current density potential curves, but useable for pitting experiments. After pickling and prepassivation epoxy embedded materials proved to be resistant to crevice corrosion at the metal-resin interface. The electrode in form of a wire was the most reliable crevice free cell design. The grinding of the samples in the pretreatment procedure was found to have a large effect on the pitting corrosion behaviour. Using different paper types with varying grit, a drop in pitting potential for rougher surfaces and an increase in metastable pitting activity was found. Increasing surface roughness led also to changes in the electronic structure of the passive film reflected by a lower bandgap energy. High alloyed stainless steels showed no breakdown potential within the examined potential range. Compared to 18/8 type stainless steels significantly less transients were found. The number of transients decreases with increasing molybdenum and chromium content

  17. Canal preparation with nickel-titanium or stainless steel instruments without the risk of instrument fracture: preliminary observations

    Directory of Open Access Journals (Sweden)

    Ghassan Yared

    2015-02-01

    Full Text Available This report introduces a novel technique that allows a safe and predictable canal negotiation, creation of a glide path and canal preparation with reciprocating nickel-titanium or stainless steel engine-driven instruments in canals where the use of rotary and the newly developed reciprocating instruments is contraindicated. In this novel technique, the instruments are used in reciprocating motion with very small angles. Hand files are not used regardless of the complexity of the canal anatomy. It also allows achieving predictable results in canal negotiation and glide path creation in challenging canals without the risk of instrument fracture.

  18. Thermal creep properties of alloy D9 stainless steel and 316 stainless steel fuel clad tubes

    International Nuclear Information System (INIS)

    Latha, S.; Mathew, M.D.; Parameswaran, P.; Bhanu Sankara Rao, K.; Mannan, S.L.

    2008-01-01

    Uniaxial thermal creep rupture properties of 20% cold worked alloy D9 stainless steel (alloy D9 SS) fuel clad tubes for fast breeder reactors have been evaluated at 973 K in the stress range 125-250 MPa. The rupture lives were in the range 90-8100 h. The results are compared with the properties of 20% cold worked type 316 stainless steel (316 SS) clad tubes. Alloy D9 SS were found to have higher creep rupture strengths, lower creep rates and lower rupture ductility than 316 SS. The deformation and damage processes were related through Monkman Grant relationship and modified Monkman Grant relationship. The creep damage tolerance parameter indicates that creep fracture takes place by intergranular cavitation. Precipitation of titanium carbides in the matrix and chromium carbides on the grain boundaries, dislocation substructure and twins were observed in transmission electron microscopic investigations of alloy D9 SS. The improvement in strength is attributed to the precipitation of fine titanium carbides in the matrix which prevents the recovery and recrystallisation of the cold worked microstructure

  19. Cryogenic properties of austenitic stainless steels for superconducting magnet

    International Nuclear Information System (INIS)

    Nohara, K.; Kato, T.; Ono, Y.; Sasaki, T.; Suzuki, S.

    1983-01-01

    The present study examines the magnetic and mechanical properties of a variety of austenitic stainless steels and high maganese steel which are candidate materials for the superconducting magnet attached to high energy particle accelerators. The effect of a specified heat treatment for the precipitation of intermetallic compound Nb3Sn to be used as superconductor on ductility and toughness are especially examined. It is found that nitrogen-strengthened austenitic stainless steels have high strength and good ductility and toughness, but that these are destroyed by precipitation treatment. The poor ductility and toughness after precipitation are caused by a weakening of the grain boundaries due to the agglomerated chromium carbide percipitates. The addition of vanadium suppresses this effect by refining the grain. Austenitic steels are found to have low magnetic permeabilities and Neel temperatures, and show serrated flow in traction test due to strained martensitic transformation. High manganese steel has extremely low permeability, a Neel temperature about room temperature, and has a serrated flow in traction test due to adiabatic deformation at liquid helium temperature

  20. Aging in PWR conditions of martensitic stainless steels

    International Nuclear Information System (INIS)

    Boursier, J.M.; Buisine, D.; Fronteau, M.; Michel, D.; Rouillon, Y.; Yrieix, B.; Meyzaud, Y.

    1998-01-01

    Martensitic stainless steels are largely used in Nuclear Power Plant (pump impeller, valve stem...) because of their high mechanical characteristics and their good resistance to corrosion. Nevertheless some of those components could operate at temperature higher than 250 deg.C, which could embrittle the material by the precipitation of a chromium-rich phase during aging. In collaboration with Framatome, Electricite de France has undertaken numerous studies in order to understand this process of embrittlement. This paper presents a review of the metallurgical investigations on martensitic stainless steels components which were performed in the EDF hot laboratory. In peculiar, it should be noted the good correlation between inservice experience and the modelling developed by EDF R and D division. Finally and in association with safety analysis, these results will allow to establish the maintenance strategy of the French Nuclear Power Plants. (authors)

  1. Precipitate evolution in low-nickel austenitic stainless steels during neutron irradiation at very low dose rates

    International Nuclear Information System (INIS)

    Isobe, Y.; Sagisaka, M.; Garner, F.; Okita, T.

    2007-01-01

    Full text of publication follows: Not all components of a fusion reactor will be subjected to high atomic displacement rates. Some components outside the plasma containment may experience relatively low displacement rates but data generated under long-term irradiation at low dpa rates is hard to obtain. In another study the neutron-induced microstructural evolution in response to long term irradiation at very low dose rates was studied for a Russian low-nickel austenitic stainless steel that is analogous to AISI 304. The irradiated samples were obtained from an out-of-core anti-crush support column for the BN-600 fast reactor with doses ranging from 1.5 to 22 dpa generated at 3x10 -9 to 4x10 -8 dpa/s. The irradiation temperatures were in a very narrow range of 370-375 deg. C. Microstructural observation showed that in addition to voids and dislocations, an unexpectedly high density of small carbide precipitates was formed that are not usually observed at higher dpa rates in this temperature range. These results required us to ask if such unexpected precipitation was anomalous or was a general feature of low-flux, long-term irradiation. It is shown in this paper that a similar behavior was observed in a western stainless steel, namely AISI 304 stainless steel, irradiated at similar temperatures and dpa rates in the EBR-II fast reactor, indicating that irradiation at low dpa rates for many years leads to a different precipitate microstructure and therefore different associated changes in matrix composition than are generated at higher dpa rates. One consequence of this precipitation is a reduced lattice parameter of the alloy matrix, leading to densification that increases in strength with increasing temperature and dose. A. non-destructive method to evaluate these precipitates is under development and is also discussed in this paper. (authors)

  2. Filler metal selection for welding a high nitrogen stainless steel

    Science.gov (United States)

    Du Toit, Madeleine

    2002-06-01

    Cromanite is a high-strength austenitic stainless steel that contains approximately 19% chromium, 10% manganese, and 0.5% nitrogen. It can be welded successfully, but due to the high nitrogen content of the base metal, precautions have to be taken to ensure sound welds with the desired combination of properties. Although no matching filler metals are currently available, Cromanite can be welded using a range of commercially available stainless steel welding consumables. E307 stainless steel, the filler metal currently recommended for joining Cromanite, produces welds with mechanical properties that are generally inferior to those of the base metal. In wear applications, these lower strength welds would probably be acceptable, but in applications where full use is made of the high strength of Cromanite, welds with matching strength levels would be required. In this investigation, two welding consumables, ER2209 (a duplex austenitic-ferritic stainless steel) and 15CrMn (an austenitic-manganese hardfacing wire), were evaluated as substitutes for E307. When used to join Cromanite, 15CrMn produced welds displaying severe nitrogen-induced porosity, and this consumable is therefore not recommended. ER2209, however, outperformed E307, producing sound porosity-free welds with excellent mechanical properties, including high ductility and strength levels exceeding the minimum limits specified for Cromanite.

  3. V and Nb Influence on the Austenitic Stainless Steel Corrosion in 0.1 M HCl

    Directory of Open Access Journals (Sweden)

    Amel GHARBI

    2014-05-01

    Full Text Available Vanadium and niobium were added in AISI309 austenitic stainless steel composition to modify their structure and pitting corrosion resistance in 0.1 M HCl. The structural characterization was carried out by X-rays diffraction and optical microscopy. Corrosion behavior was investigated using potentiodynamic tests and electrochemical impedance measurements (EIS .Results showed that vanadium and niobium addition precipitated stable carbides (VC, NbC to chromium carbides’ detriment and improved austenitic stainless steel corrosion resistance.

  4. Comparison of Solid and Hollow Torque Transducer Shaft Response in a High Alloy Stainless Steel

    Science.gov (United States)

    Milby, Christopher L.; Hecox, Bryan G.; Wiewel, Joseph L.; Boley, Mark S.

    2007-03-01

    Recent investigations of the torque transducer response function (ambient field signal versus applied torque or shear stress) have been conducted in a 13% chromium and 8% nickel stainless steel alloy in both the hollow shaft and solid shaft configuration. An understanding of both is needed for applications with differing yield strength and hardness requirements. Axial hysteresis measurements conducted before and after heat treatment exhibited little difference in coercivity and retentivity between the two sample types. However, the field mapping and transducer sensitivity studies showed the hollow shaft configuration to have a far superior degree of polarization in the sensory region and to exhibit an enhanced sensitivity, especially after heat treatment. This is most likely due to its more efficient provision of closed circumferential geometry for the field lines and improved grain alignment during heat treatment.

  5. Low temperature sensitization of austenitic stainless steel: an ageing effect during BWR service

    International Nuclear Information System (INIS)

    Shah, B.K.; Sinha, A.K.; Rastogi, P.K.; Kulkarni, P.G.

    1994-01-01

    Sensitization in austenitic stainless steel refers to chromium carbide precipitation at the grain boundaries with concomitant depletion of chromium below 12% near grain boundaries. This makes the material susceptible to either intergranular corrosion (IGC) or intergranular stress corrosion cracking (IGSCC). This effect is predominant whenever austenitic stainless steel is subjected to thermal exposure in the temperature range 723-1073K either during welding or during heat treatment. Low temperature sensitization (LTS) refers to sensitization at temperature below the typical range of sensitization i.e. 723-1073K. A prerequisite for LTS phenomenon is reported to be the presence of chromium carbide nuclei at the grain boundaries which can grow during boiling water reactor service even at a relatively lower temperature of around 560K. LTS can lead to failure of BWR pipe due to IGSCC. The paper reviews the phenomenological and mechanistic aspects of LTS. Studies carried out regarding effect of prior cold work on LTS are reported. Summary of the studies reported in literature to examine the occurrence of LTS during BWR service has also been included. (author). 10 refs., 3 figs

  6. Microstructure of rapidly solidified Al2O3-dispersion-strengthened Type 316 stainless steel

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  7. Behaviour of glass and thermal protective coatings on stainless steels in the nitrogen tetroxide based coolant

    International Nuclear Information System (INIS)

    Bakalin, Yu.I.; Dobrunova, V.M.; Doroshkevich, V.N.; Nesterenko, V.B.; Trubnikov, V.P.

    1985-01-01

    The technology of application of glass and enamel protective coatings on stainless steel has been examined, their testing in the medium of nitrogen tetroxide based coolant with different content of nitric acid has been carried out, the basic characteristics of the coatings after testing have been defined. Chromium-nickel austenitic 12kh18n10t steel, widely used in the nuclear power, have been chosen as a basic object of examination. The coatings have been tested in nitrogen oxide at P=12.0 MPa, temperature 310 deg C and 0.1% HNO 3 , and also in the medium of vat residue of the rectifying tower with nitric acid content up to 25 mass %. Tests of the coatings have demonstrated their sufficiently high stability, especially of those based on enamels A-20 and BK-5. These coatings are characterised by satisfactory performance and can be used for corrosion protection of the materials used in nuclear power

  8. Influence of alloying elements on the corrosion properties of shape memory stainless steels

    International Nuclear Information System (INIS)

    Della Rovere, C.A.; Alano, J.H.; Silva, R.; Nascente, P.A.P.; Otubo, J.; Kuri, S.E.

    2012-01-01

    Highlights: ► The corrosion properties of three Fe–Mn–Si–Cr–Ni–(Co) shape-memory stainless steels (SMSSs) were compared with those of a type 304 (SS 304) austenitic stainless steel. ► A considerably high Si content (about 40 at%) is present in the anodic passive films formed on SMSSs in 0.5 M H 2 SO 4 solution. ► The high protectiveness of the anodic passive film formed on SMSSs in 0.5 M H 2 SO 4 solution results from a protective film consisting of a (Fe, Cr)–mixed silicate. ► The SMSSs exhibited higher corrosion resistance than SS 304 in highly oxidizing environments. ► The SMSSs showed poor corrosion resistance in 3.5% NaCl solution compared to that of SS 304. - Abstract: The corrosion properties of three Fe–Mn–Si–Cr–Ni–(Co) shape memory stainless steels were studied based on X-ray photoelectron spectroscopy (XPS) analyses, immersion and polarization tests. The test results were compared with those of a type 304 austenitic stainless steel. The XPS analyses indicated substantial Si content in the anodic passive films formed on shape memory stainless steels in sulfuric acid solution and that the high protectiveness of these films results from a protective film consisting of a (iron, chromium)–mixed silicate. The corrosion rate of the shape memory stainless steels in boiling nitric acid solution was lower than that of austenitic stainless steel. The high silicon content was found to play an important role in the corrosion behavior of these shape memory alloys in highly oxidizing environments. Due to their high manganese content, the shape memory stainless steels showed poor corrosion behavior in 3.5% sodium chloride solution when compared with austenitic stainless steel.

  9. The role of duplex stainless steels for downhole tubulars

    International Nuclear Information System (INIS)

    Francis, R.

    1993-01-01

    In sour conditions there is an increasing trend to turn to corrosion resistant alloys for downhole tubulars. The most commonly used CRA tubular is 13Cr, and there are thousands of feet in service. However, there are limits to the use of 13Cr, ie., the risk of sulphide stress corrosion cracking at high H 2 S levels, and the possibility of pitting or high corrosion rates in waters with high chloride contents. Where the service conditions are felt to be too severe for 13Cr alloys it has been traditional to switch to nickel base alloys such as alloys 825 and C-276 (UNS N08825 and N10276). The alloys are much more expensive than 13Cr, and in recent years the duplex stainless steels have been selected as alloys with superior corrosion and SSCC resistance compared with 13Cr, and having lower cost than nickel alloys. Originally the 22Cr duplex alloy (UNS 31803) was used, but more recently the 25Cr super duplex alloys (UNS S32760 and S32750) have become more available. The present paper reviews the data available for 13Cr and the limits of applicability. Data is also presented for laboratory tests for both the 22Cr and 25Cr super duplex alloys. There is extensive service experience with both 22Cr and 25Cr super duplex in the North Sea, covering both downhole tubulars, manifold and post wellhead equipment. Data is presented showing some of the sour condition being experienced in the North Sea by super duplex alloys. These results show that there is a substantial gap between the limits of use for 13Cr and the 25Cr super duplex stainless steel alloys. This means that in many sour environments super duplex stainless steel provides a cost effective alternative to nickel-base alloys

  10. Chromium steel corrosion rates and mechanisms in aqueous nickel chloride at 300C

    International Nuclear Information System (INIS)

    Forrest, J.E.; Broomfield, J.P.; Mitra, P.K.

    1985-01-01

    Rapid corrosion of PWR steam generator carbon steel support structures and consequential denting of steam generator tubes led to investigation of alternative support designs and materials. In recent designs of steam generators the carbon steel drilled hole tube support plate has been replaced by one of quatrefoil or trefoil shape to minimize the contact area. These plates are now made of more corrosion resistant chromium steel (approx. 12%Cr) to ensure that they are less vulnerable to attack in the event of adverse boiler water chemistry. This study was initiated to examine the corrosion behavior of a range of chromium steels in the acid chloride environments characteristic of tube/support plate crevices under adverse boiler water conditions. Objectives of the study were to: 1) determine the relative susceptibility of candidate tube support plate steels to acid chloride corrosion; 2) investigate the corrosion product morphology and its relationship to the corrosion mechanism; 3) determine the effect of environment aggressiveness on 12%Cr (A405) steel corrosion rates and mechanisms; and 4) investigate the effect of restraint stress/environment on denting potential of A405. Experimental method and results are discussed

  11. An in vitro Evaluation of Friction Characteristics of Conventional Stainless Steel and Self-ligating Stainless Steel Brackets with different Dimensions of Archwires in Various Bracket-archwire Combination.

    Science.gov (United States)

    Sridharan, K; Sandbhor, Shailesh; Rajasekaran, U B; Sam, George; Ramees, M Mohamed; Abraham, Esther A

    2017-08-01

    The purpose of this research is to compare the frictional attributes of stainless steel conventional brackets and self-ligating stainless steel brackets with different dimensions of archwires. The test was carried with two sets of maxillary brackets: (1) Conventional stainless steel (Victory Series), (2) stainless steel self-ligating (SmartClip) without first premolar brackets. Stainless steel, nickel-titanium (NiTi), and beta-Ti which are the types of orthodontic wire alloys were tested in this study. To monitor the frictional force, a universal testing machine (Instron 33R 4467) that comprises 10 kg tension load cell was assigned on a range of 1 kg and determined from 0 to 2 kg, which allows moving of an archwire along the brackets. One-way analysis of variance was used to test the difference between groups. To analyze the statistical difference between the two groups, Student's t-test was used. For Victory Series in static friction, p-value was 0.946 and for kinetic friction it was 0.944; at the same time for SmartClip, the p value for static and kinetic frictional resistance was 0.497 and 0.518 respectively. Hence, there was no statistically significant difference between the NiTi and stainless steel archwires. It is concluded that when compared with conventional brackets with stainless steel ligatures, self-ligating brackets can produce significantly less friction during sliding. Beta-Ti archwires expressed high amount of frictional resistance and the stainless steel archwires comprise low frictional resistance among all the archwire materials. In orthodontics, frictional resistance has always had a major role. Its ability to impair tooth movement leads to the need for higher forces to move the teeth and it extends the treatment time which results in loss of posterior anchorage. Friction in orthodontics is related with sliding mechanics when a wire is moving through one or a series of bracket slots.

  12. Characteristic of Low Temperature Carburized Austenitic Stainless Steel

    Science.gov (United States)

    Istiroyah; Pamungkas, M. A.; Saroja, G.; Ghufron, M.; Juwono, A. M.

    2018-01-01

    Low temperature carburizing process has been carried out on austenitic stainless steel (ASS) type AISI 316L, that contain chromium in above 12 at%. Therefore, conventional heat treatment processes that are usually carried out at high temperatures are not applicable. The sensitization process due to chromium migration from the grain boundary will lead to stress corrosion crack and decrease the corrosion resistance of the steel. In this study, the carburizing process was carried out at low temperatures below 500 °C. Surface morphology and mechanical properties of carburized specimens were investigated using optical microscopy, non destructive profilometer, and Vicker microhardness. The surface roughness analysis show the carburising process improves the roughness of ASS surface. This improvement is due to the adsorption of carbon atoms on the surface of the specimen. Likewise, the hardness test results indicate the carburising process increases the hardness of ASS.

  13. Segregation effects in welded stainless steels

    International Nuclear Information System (INIS)

    Akhter, J.I.; Shoaid, K.A.; Ahmed, M.; Malik, A.Q.

    1987-01-01

    Welding of steels causes changes in the microstructure and chemical composition which could adversely affect the mechanical and corrosion properties. The report describes the experimental results of an investigation of segregation effects in welded austenitic stainless steels of AISI type 304, 304L, 316 and 316L using the techniques of scanning electron microscopy and electron probe microanalysis. Considerable enhancement of chromium and carbon has been observed in certain well-defined zones on the parent metal and on composition, particularly in the parent metal, in attributed to the formation of (M 23 C 6 ) precipitates. The formation of geometrically well-defined segregation zones is explained on the basis of the time-temperature-precipitation curve of (M 23 C 6 ). (author)

  14. The effect of σ-phase precipitation at 800°C on the corrosion resistance in sea-water of a high alloyed duplex stainless steel

    NARCIS (Netherlands)

    Wilms, M.E.; Gadgil, V.J.; Krougman, J.M.; Ijsseling, F.P.

    1994-01-01

    Super-duplex stainless steels are recently developed high alloyed stainless steels that combine good mechanical properties with excellent corrosion resistance. Because of a high content of chromium and molybdenum, these alloys are susceptible to σ-phase precipitation during short exposure to

  15. Investigation of the applicability of some pre expressions for austenitic stainless steels

    International Nuclear Information System (INIS)

    Alfonsson, E.; Qvarfort, R.

    1992-01-01

    The alloying elements known to be most important for the pitting resistance of austenitic stainless steels are chromium, molybdenum and nitrogen. Several authors have tried to quantify the influence of these elements by expressions giving the relative influence of each element. By such an expression a ''pitting resistance equivalent, PRE'', can be calculated for a certain alloy. Recently it has become rather common among both producers and users of stainless steels to discuss pitting resistance in terms of PRE. In the present work, critical pitting temperatures, CPT, was determined in 1 M NaCl for a wide spectrum of austenitic stainless steels. With a newly developed electrochemical cell, the CPT can be determined with high accuracy as crevice corrosion in the specimen mount can be completely eliminated during test. The correlation between the experimental results and some PRE expressions from the literature is discussed

  16. Anti corrosion layer for stainless steel in molten carbonate fuel cell - comprises phase vapour deposition of titanium nitride, aluminium nitride or chromium nitride layer then oxidising layer in molten carbonate electrolyte

    DEFF Research Database (Denmark)

    2000-01-01

    Forming an anticorrosion protective layer on a stainless steel surface used in a molten carbonate fuel cell (MCFC) - comprises the phase vapour deposition (PVD) of a layer comprising at least one of titanium nitride, aluminium nitride or chromium nitride and then forming a protective layer in situ...

  17. Effect of prior deformation on microstructural development and Laves phase precipitation in high-chromium stainless steel.

    Science.gov (United States)

    Hsiao, Z-W; Chen, D; Kuo, J-C; Lin, D-Y

    2017-04-01

    This study investigated the influence of deformation on precipitation behaviour and microstructure change during annealing. Here, the prior deformation of high-chromium stainless steel was tensile deformation of 3%, 6% and 10%, and the specimens were then annealed at 700˚C for 10 h. The specimens were subsequently analyzed using backscattered electron image and electron backscattering diffraction measurements with SEM. Compared with the deformation microstructure, the grains revealed no preferred orientation. The precipitates of TiN and NbC were formed homogenously in the grain interior and at grain boundaries after annealing. Fine Laves phase precipitates were observed in grains and along subgrain boundaries as the deformation increased. Furthermore, the volume fraction of Laves phase increased, but the average particle diameter of precipitate was reduced as the deformation increased. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  18. Microstructural features of dissimilar welds between 316LN austenitic stainless steel and alloy 800

    International Nuclear Information System (INIS)

    Sireesha, M.; Sundaresan, S.

    2000-01-01

    For joining type 316LN austenitic stainless steel to modified 9Cr-1Mo steel for power plant application, a trimetallic configuration using an insert piece (such as alloy 800) of intermediate thermal coefficient of expansion (CTE) has been sometimes suggested for bridging the wide gap in CTE between the two steels. Two joints are thus involved and this paper is concerned with the weld between 316LN and alloy 800. These welds were produced using three types of filler materials: austenitic stainless steels corresponding to 316,16Cr-8Ni-2Mo, and the nickel-base Inconel 182 1 . The weld fusion zones and the interfaces with the base materials were characterised in detail using light and transmission electron microscopy. The 316 and Inconel 182 weld metals solidified dendritically, while the 16-8-2(16%Cr-8%Ni-2%Mo) weld metal showed a predominantly cellular substructure. The Inconel weld metal contained a large number of inclusions when deposited from flux-coated electrodes, but was relatively inclusion-free under inert gas-shielded welding. Long-term elevated-temperature aging of the weld metals resulted in embrittling sigma phase precipitation in the austenitic stainless steel weld metals, but the nickel-base welds showed no visible precipitation, demonstrating their superior metallurgical stability for high-temperature service. (orig.)

  19. Prevention of burn-on defect on surface of hydroturbine blade casting of ultra-low-carbon refining stainless steel

    Directory of Open Access Journals (Sweden)

    Li Ling

    2008-08-01

    Full Text Available The burn-on sand is common surface defect encountered in CO2-cured silicate-bonded sand casting of hydroturbine blade of ultra-low-carbon martensitic stainless steel, its feature, causes and prevention measures are presented in this paper. Experiments showed that the burn-on defect is caused by oxidization of chromium in the molten steel at high temperature and can be effectively eliminated by using chromium-corundum coating.

  20. Mechanical characteristics of welded joints between different stainless steels grades

    Science.gov (United States)

    Topolska, S.; Łabanowski, J.

    2017-08-01

    Investigation of mechanical characteristics of welded joints is one of the most important tasks that allow determining their functional properties. Due to the very high, still rising, cost of some stainless steels it is justified, on economic grounds, welding austenitic stainless steel with steels that are corrosion-resistant like duplex ones. According to forecasts the price of corrosion resistant steels stil can increase by 26 ÷ 30%. For technical reasons welded joints require appropriate mechanical properties such as: tensile strength, bending, ductility, toughness, and resistance to aggressive media. Such joints are applied in the construction of chemical tankers, apparatus and chemical plants and power steam stations. Using the proper binder makes possible the welds directly between the elements of austenitic stainless steels and duplex ones. It causes that such joits behave satisfactorily in service in such areas like maritime constructions and steam and chemical plants. These steels have high mechanical properties such as: the yield strength, the tensile strength and the ductility as well as the resistance to general corrosion media. They are resistant to both pitting and stress corrosions. The relatively low cost of production of duplex steels, in comparison with standard austenitic steels, is inter alia, the result of a reduced amount of scarce and expensive Nickel, which is seen as a further advantage of these steels.

  1. Effect of water purity on intergranular stress corrosion cracking of stainless steel and nickel alloys in BWRs

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, B. [Structural Integrity Associates (United States); Garcia, S. [Electric Power Research Institute (United States)

    2011-07-01

    Boiling water reactors (BWRs) operate with very high purity water. While even the utilization of a very low conductivity water (e.g., 0.06 {mu}S/cm) coolant cannot prevent intergranular stress corrosion cracking (IGSCC) of sensitized stainless steel and nickel alloys under oxygenated conditions, the presence of certain impurities in the coolant can dramatically increase the probability of this most insidious form of corrosion. The goal of this paper is to present the effect of effect of only a few ionic impurities plus zinc on the IGSCC propensities of BWR stainless steel piping and reactor internals under both oxygenated, i.e., normal water chemistry (NWC) and deoxygenated, i.e., hydrogen water chemistry (HWC) conditions. More specifically, of the numerous impurities identified in the BWR coolant (e.g., lithium, sodium, potassium, silica, borate, chromate, phosphate, sulphate, chloride, nitrate, cuprous, cupric, ferrous, etc.) only strong acid anions sulfate and chloride that are stable in the highly reducing crack tip environment rather than the bulk water conductivity will be discussed in detail. Nitrate will be briefly discussed as representing a species that is not thermodynamically stable in the crack while the effects of zinc is discussed as a deliberate additive to the BWR environment. (authors)

  2. Effect of nitrogen and boron on weldability of austenitic stainless steels

    International Nuclear Information System (INIS)

    Bhaduri, A.K.; Albert, S.K.; Srinivasan, G.; Divya, M.; Das, C.R.

    2012-01-01

    Hot cracking is a major problem in the welding of austenitic stainless steels, particularly the fully austenitic grades. A group of alloys of enhanced-nitrogen 316LN austenitic stainless steel is being developed for structural components of the Indian Fast Reactor programme. Studying the hot cracking behaviour of this nitrogen-enhanced austenitic stainless steel is an important consideration during welding, as this material solidifies without any residual delta ferrite in the primary austenitic mode. Nitrogen has potent effects on the solidification microstructure, and hence has a strong influence on the hot cracking behaviour. Different heats of this material were investigated, which included fully austenitic stainless steels containing 0.070.22 wt% nitrogen. Also, borated austenitic stainless steels, such as type 304B4, have been widely used in the nuclear applications primarily due to its higher neutron absorption efficiency. Weldability is a major concern for this alloy due to the formation of low melting eutectic phase that is enriched with iron, chromium, molybdenum and boron. Fully austenitic stainless steels are prone to hot cracking during welding in the absence of a small amount of delta ferrite, especially for compositions rich in elements like boron that increases the tendency to form low melting eutectics. Detailed weldability investigations were carried out on a grade 304B4 stainless steel containing 1.3 wt% boron. Among the many approaches that have been used to determine the hot cracking susceptibility of different alloys, Variable-Restraint (Varestraint) weld test and Hot Ductility (Gleeble) tests are commonly used to evaluate the weldability of austenitic alloys. Hence, investigations on these materials consisted of detailed metallurgical characterization and weldability studies that included studying both the fusion zone and liquation cracking susceptibility, using Varestraint tests at 0.254.0%, strain levels and Gleeble (thermo

  3. Modeling of Ni Diffusion Induced Austenite Formation in Ferritic Stainless Steel Interconnects

    DEFF Research Database (Denmark)

    Chen, Ming; Molin, Sebastian; Zhang, L.

    2015-01-01

    Ferritic stainless steel interconnect plates are widely used in planar solid oxide fuel cell (SOFC) or electrolysis cell (SOEC) stacks. During stack production and operation, nickel from the Ni/YSZ fuel electrode or from the Ni contact component diffuses into the IC plate, causing transformation...... of the ferritic phase into an austenitic phase in the interface region. This is accompanied with changes in volume and in mechanical and corrosion properties of the IC plates. In this work, kinetic modeling of the inter-diffusion between Ni and FeCr based ferritic stainless steel was conducted, using the CALPHAD...

  4. Corrosion Characterization in Nickel Plated 110 ksi Low Alloy Steel and Incoloy 925: An Experimental Case Study

    Science.gov (United States)

    Thomas, Kiran; Vincent, S.; Barbadikar, Dipika; Kumar, Shresh; Anwar, Rebin; Fernandes, Nevil

    2018-04-01

    Incoloy 925 is an age hardenable Nickel-Iron-Chromium alloy with the addition of Molybdenum, Copper, Titanium and Aluminium used in many applications in oil and gas industry. Nickel alloys are preferred mostly in corrosive environments where there is high concentration of H2S, CO2, chlorides and free Sulphur as sufficient nickel content provides protection against chloride-ion stress-corrosion cracking. But unfortunately, Nickel alloys are very expensive. Plating an alloy steel part with nickel would cost much lesser than a part make of nickel alloy for large quantities. A brief study will be carried out to compare the performance of nickel plated alloy steel with that of an Incoloy 925 part by conducting corrosion tests. Tests will be carried out using different coating thicknesses of Nickel on low alloy steel in 0.1 M NaCl solution and results will be verified. From the test results we can confirm that Nickel plated low alloy steel is found to exhibit fairly good corrosion in comparison with Incoloy 925 and thus can be an excellent candidate to replace Incoloy materials.

  5. Corrosion behaviour of austenitic stainless steel, nickel-base alloy and its weldments in aqueous LiBr solutions

    Energy Technology Data Exchange (ETDEWEB)

    Blasco-Tamarit, E.; Igual-Munoz, A.; Garcia Anton, J.; Garcia-Garcia, D. [Departamento de Ingenieria Quimica y Nuclear. E.T.S.I.Industriales, Universidad Politecnica de Valencia, P.O. Box 22012 E-46071 Valencia (Spain)

    2004-07-01

    With the advances in materials production new alloys have been developed, such as High- Alloy Austenitic Stainless Steels and Nickel-base alloys, with high corrosion resistance. These new alloys are finding applications in Lithium Bromide absorption refrigeration systems, because LiBr is a corrosive medium which can cause serious corrosion problems, in spite of its favourable properties as absorbent. The objective of the present work was to study the corrosion resistance of a highly alloyed austenitic stainless steel (UNS N08031) used as base metal, a Nickel-base alloy (UNS N06059) used as its corresponding filler metal, and the weld metal obtained by the Gas Tungsten Arc Welding (GTAW) procedure. The materials have been tested in different LiBr solutions (400 g/l, 700 g/l, 850 g/l and a commercial 850 g/l LiBr heavy brine containing Lithium Chromate as corrosion inhibitor), at 25 deg. C. Open Circuit Potential tests and potentiodynamic anodic polarization curves have been carried out to obtain information about the general electrochemical behaviour of the materials. The polarization curves of all the alloys tested were typical of passivable materials. Pitting corrosion susceptibility has been evaluated by means of cyclic potentiodynamic curves, which provide parameters to analyse re-passivation properties. The galvanic corrosion generated by the electrical contact between the welded and the base material has been estimated from the polarization diagrams according to the Mixed Potential Method. Samples have been etched to study the microstructure by Scanning Electron Microscopy (SEM). The results demonstrate that the pitting resistance of all these materials increases as the LiBr concentration decreases. In general, the presence of chromate tended to shift the pitting potential to more positive values than those obtained in the 850 g/l LiBr solution. (authors)

  6. Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045 and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) plate, sheet and strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045 and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) plate, sheet and strip

  7. Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) rod, bar, and wire

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nickel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) rod, bar, and wire

  8. Effect of dissolved hydrogen concentration on IASCC initiation susceptibility of type 316 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Min-Jae; Kim, Sung Woo; Hwang, Seong Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    The effect of DH concentration on PWSCC of nickel based alloys has been studied, higher dissolved hydrogen strategy is being considered to obtain partial mitigation of PWSCC. In the case of stainless steels, it is necessary to research the effect of DH concentration on irradiation assisted stress corrosion cracking(IASCC). In this research, we tried to evaluate the effect of DH concentration on IASCC initiation susceptibility using the proton irradiated type 316 stainless steels under the condition of simulated primary water. The slow strain rate tests were performed using the proton irradiated type 316 stainless steels at the simulated primary water conditions, crack length per unit area for all tested specimens were calculated. IASCC initiation susceptibility was increased by increasing irradiation doses and by increasing DH concentration.

  9. An investigation of sodium iodide solubility in sodium-stainless steel systems

    International Nuclear Information System (INIS)

    Sagawa, Norihiko; Tashiro, Suguru

    1996-01-01

    Sodium iodide and major constituents of stainless steel in sodium are determined by using the steel capsules to obtain a better understanding on contribution of the constituents to the apparent iodide solubility in sodium. The capsule loaded with 20 g sodium and 0.1 - 0.3 g powder of sodium iodide is heated at its upper part in a furnace and cooled at its bottom on brass plates to establish a large temperature gradient along the capsule tube. After a given period of equilibration, the iodide and constituents are fixed in solidified sodium by quick quenching of the capsules. Sodium samples are taken from the sectioned capsule tube and submitted to sodium dissolution by vaporized water for determination of the iodine and to vacuum distillation for determination of the metal elements. Iron and nickel concentrations are observed to be lower in the samples at higher iodine concentrations. Chromium and manganese concentrations are seen to be insensitive to the iodine concentrations. The observations can be interpreted by a model that sodium oxide combines with metal iodide in sodium to form a complex compound and with consideration that the compound will fall and deposit onto the bottom of the capsule by thermal diffusion. (author)

  10. The low-temperature aging embrittlement in a 2205 duplex stainless steel

    International Nuclear Information System (INIS)

    Weng, K.L.; Chen, H.R.; Yang, J.R.

    2004-01-01

    The effect of isothermal treatment (at temperatures ranging between 400 and 500 deg. C) on the embrittlement of a 2205 duplex stainless steel (with 45 ferrite-55 austenite, vol.%) has been investigated. The impact toughness and hardness of the aged specimens were measured, while the corresponding fractography was studied. The results show that the steel is susceptible to severe embrittlement when exposed at 475 deg. C; this aging embrittlement is analogous with that of the ferritic stainless steels, which is ascribed to the degenerated ferrite phase. High-resolution transmission electron microscopy reveals that an isotropic spinodal decomposition occurred during aging at 475 deg. C in the steel studied; the original δ-ferrite decomposed into a nanometer-scaled modulated structure with a complex interconnected network, which contained an iron-rich BCC phase (α) and a chromium-enriched BCC phase (α'). It is suggested that the locking of dislocations in the modulated structure leads to the severe embrittlement

  11. An evaluation of the effect of surface chromium concentration on the oxidation of a stainless steel

    International Nuclear Information System (INIS)

    Lobb, R.C.; Evans, H.E.

    1983-01-01

    Short-term oxidation tests have been performed at 850 deg C in a CO 2 -based atmosphere on 20Cr-25Ni-Nb-stabilized steels previously exposed to dynamic vacuum at 1000 deg C. This pre-treatment preferentially removes chromium from the metal surface and is always detrimental to the oxidation properties. It is shown that porous, iron-rich oxides initially form on specimens with surface chromium concentrations 18.5 w/o chromium, a protective surface layer is produced. It is suggested that the transition between these extremes is determined by nucleation conditions and, in the present steels, it is shown how the metal grain size plays a significant role. (author)

  12. Microstructure characterization in the weld joint of a high nickel austenitic alloy and Cr18-Ni8 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Na; Li, Yajiang; Wang, Juan [Shandong Univ., Jinan (CN). Key Lab. for Liquid - Solid Structural Evolution and Processing of Materials (Ministry of Education)

    2012-06-15

    High nickel austenitic alloy, 6 mm thick, and Cr18-Ni8 stainless steel with a thickness of 0.6 mm were joined by pulsed current tungsten inert gas arc welding without filler metal in this work. Metallographic examination, microhardness measurement and electron microprobe analysis were used to reveal microstructural characteristics in the joint. The results indicated that the weld metal consisted of {gamma}-austenite, {delta}-ferrite and carbides without the appearance of martensite. There were dendrite crystals at the edge of the weld metal near the high nickel austenitic alloy and isometric crystals in the center of the weld metal. The microhardness of the weld metal was the highest due to the existence of carbides and its finer structure. Graphite flakes were still embedded in the austenite matrix of the heat-affected zone without the formation of martensite. (orig.)

  13. Intergranular Corrosion of 316L Stainless Steel by Aging and UNSM (Ultrasonic Nano-crystal Surface Modification) treatment

    International Nuclear Information System (INIS)

    Lee, J. H.; Kim, Y. S.

    2015-01-01

    Austenitic stainless steels have been widely used in many engineering fields because of their high corrosion resistance and good mechanical properties. However, welding or aging treatment may induce intergranular corrosion, stress corrosion cracking, pitting, etc. Since these types of corrosion are closely related to the formation of chromium carbide in grain boundaries, the alloys are controlled using methods such as lowering the carbon content, solution heat treatment, alloying of stabilization elements, and grain boundary engineering. This work focused on the effects of aging and UNSM (Ultrasonic Nano-crystal Surface Modification) on the intergranular corrosion of commercial 316L stainless steel and the results are discussed on the basis of the sensitization by chromium carbide formation and carbon segregation, residual stress, grain refinement, and grain boundary engineering

  14. Effects of delta ferrite content on the mechanical properties of E308-16 stainless steel weld metal

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, D. P.; Vandergriff, D. M.; Gray, R. J.

    1978-01-01

    The effects of ferrite content on the properties of type 308 stainless steel shielded metal-arc (SMA) welds were investigated. Welds were made at four levels of ferrite content ranging from 2 to 15 FN (Ferrite Number). Creep and tensile tests were performed. Specimens were aged at 1100/sup 0/C (593/sup 0/C) for times up to 10,000 h (36 Ms) and Charpy V-notch impact tests were performed. Chemical analysis of the original deposits, Magne-gage evaluations, and metallographic evaluation of tested specimens were made. The E308-16 stainless steel electrodes were formulated to produce SMA welds with 2, 5, 9, and 15 FN. The ferrite number was made to vary by varying the nickel and chromium concentrations. Magne-gage determinations revealed that as-welded structures contained an average of 1.8, 4.2, 9.6, and 14.5 FN, respectively. Chemical anslysis of these deposits revealed no unusually high concentrations of tramp elements that would significantly affect mechanical properties. The extra low-ferrite electrodes were made with a different core wire, which produced deposits with slightly higher molybdenum concentrations. This variation in molybdenum should affect properties only minimally. From these chemical analyses and a constitutional diagram, ferrite concentrations were calculated, and the results correlated with the Magne-gage values

  15. Phosphate coating on stainless steel 304 sensitized;Recubrimiento fosfatado sobre acero inoxidable 304 sensibilizado

    Energy Technology Data Exchange (ETDEWEB)

    Cruz V, J. P. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira, Km. 14.5 Carretera Tampico-Puerto Industrial Altamira, 89600 Altamira, Tamaulipas (Mexico); Vite T, J. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Castillo S, M.; Vite T, M., E-mail: jpcruz@ipn.m [IPN, Escuela Superior de Ingenieria Mecanica y Electrica, Seccion de Estudios de Posgrado e Investigacion, Unidad Profesional -Adolfo Lopez Mateos-, Zacatenco, 07738 Mexico, D. F. (Mexico)

    2009-07-01

    The stainless steel 304 can be sensitized when welding processes are applied, that causes the precipitation of chromium carbide in the grain limits, being promoted in this way the formation of galvanic cells and consequently the corrosion process. Using a phosphate coating is possible to retard the physiochemical damages that can to happen in the corrosion process. The stainless steel 304 substrate sensitized it is phosphate to base of Zn-Mn, in a immersion cell very hot. During the process was considered optimization values, for the characterization equipment of X-rays diffraction and scanning electron microscopy was used. The XRD technique confirmed the presence of the phases of manganese phosphate, zinc phosphate, as well as the phase of the stainless steel 304. When increasing the temperature from 60 to 90 C in the immersion process a homogeneous coating is obtained. (Author)

  16. Influence of chloride and bromide anions on localized corrosion of 15%Cr ferritic stainless steel

    International Nuclear Information System (INIS)

    Lee, Seung Uk; Ahn, Jae Chen; Kim, Dong Hyun; Hong, Seung Chan; Lee, Kyung Sub

    2006-01-01

    The influence of Cl - (919 ppm) and a mixture of Cl - (919 ppm) and Br - (51 ppm) on the corrosion behavior of 15%Cr ferritic stainless steel was investigated. Potentiodynamic and immersion tests were performed to examine the corrosion behavior. The size and the shape of pits were observed by optical microscope and scanning electron microscope. The oxide films formed on stainless steel were investigated by X-ray photoelectron spectroscopy (XPS). During the immersion test at 93 deg. C for 600 h, Fe and Cr were mostly corroded to iron and chromium oxides. The results of depth profiling indicate higher corrosion rate of solution containing chloride than the mixture solution. It was clear that the addition of Br - to the solution containing Cl - inhibited the localized corrosion of 15%Cr ferritic stainless steel

  17. Recycling radioactive scrap metal by producing concrete shielding with steel granules

    International Nuclear Information System (INIS)

    Sappok, M.

    1996-01-01

    Siempelkamp foundry at Krefeld, Germany, developed a method for recycling radioactively contaminated steel from nuclear installations. The material is melted and used for producing shielding plates, containers, etc., on a cast-iron basis. Because the percentage of stainless steel has recently increased significantly, problems in the production of high-quality cast iron components have also grown. The metallurgy, the contents of nickel and chromium especially, does not allow for the recycling of stainless steel in a percentage to make this process economical. In Germany, the state of the art is to use shielded concrete containers for the transport of low active waste; this concrete is produced by using hematite as an additive for increasing shielding efficiency. The plan was to produce steel granules from radioactive scrap metal as a substitute for hematite in shielding concrete

  18. Oxidation of 316 stainless steel and other alloys in prototypic GCFR environments

    International Nuclear Information System (INIS)

    Acharya, R.T.

    1980-05-01

    The oxidation behavior of type 316 stainless steel and candidate advanced alloys for the gas-cooled fast reactor (GCFR) is being investigated at General Atomic Company. The test program consists of oxidation tests in prototypic GCFR environments. Two tests have been completed to date and a third test is under way. The first test was performed in an environment containing a hydrogen/water ratio of 10. The oxidation behavior of all the alloys was good to excellent in this environment. Preferential oxidation of chromium was responsible for this behavior. The second test was performed in an environment containing a hydrogen/water ratio of 0.25, where both chromium and iron oxides are thermodynamically stable. Some of the alloys and some of the ribbed type 316 stainless steel test specimens showed unacceptable oxidation resistance in this environment. In the third test, presently under way, two different pretreatment procedures are being used to control the poor oxidation behavior observed in the second test. Early results show some degree of success

  19. Cyclic oxidation of stainless steel ferritic AISI 409, AISI 439 and AISI 441

    International Nuclear Information System (INIS)

    Salgado, Maria de Fatima; Santos, Diego Machado dos; Oliveira, Givanilson Brito de; Lins, Vanessa de Freitas Cunha

    2014-01-01

    Stainless steels have many industrial applications. The cyclic oxidation of ferritic stainless steels technical and scientific importance presents, because they are less susceptible to peeling the austenitic alloys. For the purpose of investigating the behavior of these steels under thermal cycling, cyclic oxidation of AISI 409, AISI 441 and AISI 439 was carried out in a tubular furnace under two different conditions: oxidation by dipping the steel in the synthetic condensate for 10h and without oxidation immersion in the condensate, for up to 1500h at 300° C temperature. Using techniques: SEM, EDS and XRD revealed a microstructure with increased oxidation in the samples were immersed in the condensate. The oxide film remained intact during oxidation for steels 439 and 441 409 The Steel immersed in the condensate was rupture of the film after the 20th cycle of oxidation. The chemical characterization of the films allowed the identification of elements: Chromium, Iron, Aluminium and Silicon To a great extent, Cr_2O_3. (author)

  20. Microstructure and properties of gravity sintered 316l stainless steel powder with nickel boride addition

    Directory of Open Access Journals (Sweden)

    Božić Dušan

    2016-01-01

    Full Text Available The present work demonstrates a procedure for synthesis of stainless steel powder by gravity sintering method. As an additive to the basic powder, NiB powder was added in the amount of 0.2 - 1.0 wt.%. Gravity sintering was done in vacuum, at the temperatures of 1100°C-1250°C, in the course of 3 - 60 min, using ceramic mould. Structural characterization was conducted by XRD, and microstructural analysis by optical and scanning electron microscope (SEM. Mechanical properties were investigated by tensile tests with steel rings. Density and permeability were determined by standard techniques for porous samples. Gravity sintered stainless steel with NiB addition had more superior mechanical and physico-chemical properties compared to stainless steel obtained by standard powder metallurgy procedures - pressing and sintering. [Projekat Ministarstva nauke Republike Srbije, br. 172005

  1. Kinetics of steel heavy ingot formation in dies of semicontinuous-casting machines

    International Nuclear Information System (INIS)

    Tsukerman, V.Ya.; Marchenko, I.K.

    1986-01-01

    Formation kinetics of round section ingot of up to 0.67 m in diameter was analyzed in dies of semicontinuous-casting machines on casting of the most usable assortment steels: medium-carbon low-alloyed and chromium-nickel stainless steels. It is established that solidification coefficient decreases in direct proportion to ingot diameter. Value of different-thickness ingot skin at die outlet is in direct proportion to a casted steel overheating temperature, ingot diameter and inversely proportional to the number and diameter of holes in a ladder nozzle and square root of ingot drawing rate

  2. Effects of solute interstitial elements on swelling of stainless steel

    International Nuclear Information System (INIS)

    Stiegler, J.O.; Leitnaker, J.M.; Bloom, E.E.

    1975-01-01

    High-purity stainless steel (HPS), equivalent to type 316 stainless steel in major alloy elements but with greatly reduced interstitial elements and manganese contents, was irradiated in the temperature range 725 to 875 K to fluences ranging from 1.0 to 3.5 x 10 26 neutrons/m 2 (>0.1 MeV). The HPS swelled 20 to 50 times more than commercial grade 316 stainless steel (316 SS), and about the same as commercial-purity nickel, which has about the same interstitial content as HPS. A fine-grained 316 SS in which interstitial elements but not manganese were precipitated by thermomechanical treatments also showed exaggerated swelling, approaching that of HPS, which suggests that swelling in commercial stainless steels is retarded by small amounts of interstitial elements normally present in them and not by the major alloying elements. Interstitials tend to precipitate from solution during irradiation, and bulk extractions of precipitate particles were made to evaluate the extent of the precipitation reactions. At both 643 and 853 K precipitation was clearly enhanced by irradiation significantly enough to alter the matrix composition, which suggests that swelling may be increased at high fluences over that predicted by extrapolation of lower fluence data. These observations are discussed in terms of potential behaviour of fuel cladding materials and of the validity and interpretation of accelerated schemes for simulating neutron damage. (author)

  3. Transformation and Precipitation Reactions by Metal Active Gas Pulsed Welded Joints from X2CrNiMoN22-5-3 Duplex Stainless Steels.

    Science.gov (United States)

    Utu, Ion-Dragos; Mitelea, Ion; Urlan, Sorin Dumitru; Crăciunescu, Corneliu Marius

    2016-07-21

    The high alloying degree of Duplex stainless steels makes them susceptible to the formation of intermetallic phases during their exposure to high temperatures. Precipitation of these phases can lead to a decreasing of the corrosion resistance and sometimes of the toughness. Starting from the advantages of the synergic Metal Active Gas (MAG) pulsed welding process, this paper analyses the structure formation particularities of homogeneous welded joints from Duplex stainless steel. The effect of linear welding energy on the structure morphology of the welded joints was revealed by macro- and micrographic examinations, X-ray energy dispersion analyses, measurements of ferrite proportion and X-ray diffraction analysis. The results obtained showed that the transformation of ferrite into austenite is associated with the chromium, nickel, molybdenum and nitrogen distribution between these two phases and their redistribution degree is closely linked to the overall heat cycle of the welding process. The adequate control of the energy inserted in the welded components provides an optimal balance between the two microstructural constituents (Austenite and Ferrite) and avoids the formation of undesirable intermetallic phases.

  4. Transformation and Precipitation Reactions by Metal Active Gas Pulsed Welded Joints from X2CrNiMoN22-5-3 Duplex Stainless Steels

    Directory of Open Access Journals (Sweden)

    Ion-Dragos Utu

    2016-07-01

    Full Text Available The high alloying degree of Duplex stainless steels makes them susceptible to the formation of intermetallic phases during their exposure to high temperatures. Precipitation of these phases can lead to a decreasing of the corrosion resistance and sometimes of the toughness. Starting from the advantages of the synergic Metal Active Gas (MAG pulsed welding process, this paper analyses the structure formation particularities of homogeneous welded joints from Duplex stainless steel. The effect of linear welding energy on the structure morphology of the welded joints was revealed by macro- and micrographic examinations, X-ray energy dispersion analyses, measurements of ferrite proportion and X-ray diffraction analysis. The results obtained showed that the transformation of ferrite into austenite is associated with the chromium, nickel, molybdenum and nitrogen distribution between these two phases and their redistribution degree is closely linked to the overall heat cycle of the welding process. The adequate control of the energy inserted in the welded components provides an optimal balance between the two microstructural constituents (Austenite and Ferrite and avoids the formation of undesirable intermetallic phases.

  5. Effect of chemistry variations on the short-term rupture life and tensile properties of 20% cold-worked type 316 stainless steel

    International Nuclear Information System (INIS)

    Duncan, D.R.; Paxton, M.M.

    1977-01-01

    The effects of compositional variations on the rupture life of 20% cold-worked Type 316 stainless steel were investigated at 19-ksi (131-MPa) uniaxial tensile stress and at 1400 0 F (1033 K). Forty-nine different alloys were studied, with compositional variations from nominal in carbon, nitrogen, phosphorus, sulfur, boron, manganese, copper, silicon, molybdenum, cobalt, chromium and nickel. This alloy and cold-work level represents the duct and fuel cladding material choice for the first four core loadings of the Fast Flux Test Facility, a key element in the Liquid-Metal Fast Breeder Reactor Program. Tensile properties of four of the alloys were studied at temperatures from room temperature to 1600 0 F (1144 K). Boron, nitrogen, and molybdenum plus silicon additions significantly increased rupture life, while chromium and carbon additions decreased rupture life. Molybdenum plus silicon additions increased yield and ultimate strength and ductility at 1200 0 F (922 K) and below

  6. Studies on analytical method and nondestructive measuring method on the sensitization of austenitic stainless steels

    International Nuclear Information System (INIS)

    Onimura, Kichiro; Arioka, Koji; Horai, Manabu; Noguchi, Shigeru.

    1982-03-01

    Austenitic stainless steels are widely used as structural materials for the machine and equipment of various kinds of plants, such as thermal power, nuclear power, and chemical plants. The machines and equipment using this kind of material, however, have the possibility of suffering corrosion damage while in service, and these damages are considered to be largely due to the sensitization of the material in sometimes. So, it is necessary to develop an analytical method for grasping the sensitization of the material more in detail and a quantitative nondestructive measuring method which is applicable to various kinds of structures in order to prevent the corrosion damage. From the above viewpoint, studies have been made on the analytical method based on the theory of diffusion of chromium in austenitic stainless steels and on Electro-Potentiokinetics Reactivation Method (EPR Method) as a nondestructive measuring method, using 304 and 316 austenitic stainless steels having different carbon contents in base metals. This paper introduces the results of EPR test on the sensitization of austenitic stainless steels and the correlation between analytical and experimental results. (author)

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

    Science.gov (United States)

    Khodadadi, Ali; Shamanian, Morteza; Karimzadeh, Fathallah

    2017-05-01

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

  8. Production and several properties of single crystal austenitic stainless steels

    International Nuclear Information System (INIS)

    Okamoto, Kazutaka; Yoshinari, Akira; Kaneda, Junya; Aono, Yasuhisa; Kato, Takahiko

    1998-01-01

    The single crystal austenitic stainless steels Type 316L and 304L were grown in order to improve the resistance to stress corrosion cracking (SCC) using a unidirectional solidification method which can provide the large size single crystals. The mechanical properties and the chemical properties were examined. The orientation and temperature dependence of tensile properties of the single crystals were measured. The yield stress of the single crystal steels are lower than those of the conventional polycrystal steels because of the grain boundary strength cannot be expected in the single crystal steels. The tensile properties of the single crystal austenitic stainless steel Type 316L depend strongly on the orientation. The tensile strength in orientation are about 200 MPa higher than those in the and orientations. The microstructure of the single crystal consists of a mixture of the continuous γ-austenitic single crystal matrix and the δ-ferrite phase so that the effects of the γ/δ boundaries on the chemical properties were studied. The effects of the δ-ferrite phases and the γ/δ boundaries on the resistance to SCC were examined by the creviced bent beam test (CBB test). No crack is observed in all the CBB test specimens of the single crystals, even at the γ/δ boundaries. The behavior of the radiation induced segregation (RIS) at the γ/δ boundaries in the single crystal austenitic stainless steel Type 316L was evaluated by the electron irradiation test in the high voltage electron microscope (HVEM). The depletion of oversized solute chromium at the γ/δ boundary in the single crystal austenitic stainless steel Type 316L is remarkably lower than that at the grain boundary in the polycrystalline-type 316L. (author)

  9. The observation of helium gas bubble lattices in copper, nickel and stainless steel

    International Nuclear Information System (INIS)

    Johnson, P.B.; Mazey, D.J.

    1978-10-01

    Transmission electron microscopy is used to investigate the spatial arrangement of the small gas bubbles produced in several fcc metals by 30 keV helium ion irradiation to high dose at 300K. In what is a new result for this important class of metals it is found that the helium gas bubbles lie on a superlattice having an fcc structure with principal axes aligned with those of the metal matrix. The bubble lattice constant, asub(l), is measured for a helium fluence just below the critical dose for radiation blistering of the metal surface. Implantation rates are typically approximately 10 14 He ions cm -2 sec -1 . The values of asub(l) obtained for copper, nickel and stainless steel are given. Above the critical dose the bubble lattice is seen to survive in some blister caps as well as in the region between blisters. Bubble alignment is also observed in the case of hydrogen bubbles produced in copper by low energy proton irradiation to high fluence at 300K. (author)

  10. Mechanical and microstructural integrity of nickel-titanium and stainless steel laser joined wires

    International Nuclear Information System (INIS)

    Vannod, J.; Bornert, M.; Bidaux, J.-E.; Bataillard, L.; Karimi, A.; Drezet, J.-M.; Rappaz, M.; Hessler-Wyser, A.

    2011-01-01

    The biomedical industry shows increasing interest in the joining of dissimilar metals, especially with the aim of developing devices that combine different mechanical and corrosive properties. As an example, nickel-titanium shape memory alloys joined to stainless steel are very promising for new invasive surgery devices, such as guidewires. A fracture mechanics study of such joined wires was carried out using in situ tensile testing and scanning electron microscopy imaging combined with chemical analysis, and revealed an unusual fracture behaviour at superelastic stress. Nanoindentation was performed to determine the mechanical properties of the welded area, which were used as an input for mechanical computation in order to understand this unexpected behaviour. Automated image correlation allowed verification of the mechanical modelling and a reduced stress-strain model is proposed to explain the special fracture mechanism. This study reveals the fact that tremendous property changes at the interface between the NiTi base wire and the weld area have more impact on the ultimate tensile strength than the chemical composition variation across the welded area.

  11. Investigation of alternative phosphating treatments for nickel and hexavalent chromium elimination; Investigacao de tratamentos alternativos de fosfatizacao para eliminacao do niquel e cromo hexavalente

    Energy Technology Data Exchange (ETDEWEB)

    Jazbinsek, Luiz Antonio Rossi

    2014-07-01

    The phosphating processes are widely used in industry as surface treatments for metals, especially for low thickness plates, improving the adhesion between the metallic surface and the paint coating, and increasing the durability of paint systems against corrosion attacks. The tricationic phosphates containing zinc, nickel and manganese are commonly applied on steel. There is much discussion about the replacement of nickel by another element in order to have an environmentally friendly phosphating process. Niobium as a replacement for nickel has been evaluated. The most significant environmental impacts of phosphating processes are related to the presence of nickel and hexavalent chromium used in the process, this last as a passivation treatment. Nickel and hexavalent chromium are harmful to human and environment leading to contamination of water and soil. In the present study phosphate layers containing zinc, manganese and niobium have been evaluated and characterized on galvanized steel, and the results were compared with phosphates containing zinc, manganese and nickel, or a bicationic phosphate layer with zinc and manganese. Although the use of hexavalent chromium is not recommended worldwide, it is still used in processes for sealing the porosity of phosphate layers. This element is carcinogenic and has been associated with various diseases. Due to the passivation characteristics of niobium, this study also evaluated the tricationic bath containing niobium ammonium oxalate as a passivation treatment. The results showed that it could act as a replacement for the hexavalent chromium. The results of the present study showed that formulations containing niobium are potential replacements for hexavalent chromium and similar corrosion protection was obtained for the phosphate containing nickel or that with niobium. The morphology observed by scanning electron microscopy, gravimetric tests, porosity and adhesion evaluation results indicated that the phosphate

  12. Pitting corrosion and crevice corrosion of an advanced chromium-based stainless steel

    International Nuclear Information System (INIS)

    Kohler, M.

    1999-01-01

    Alloy 33 is a (wt. %) 33 Cr-32Fe-31Ni-1.6Mo-0.6CU-0.4N austenitic stainless steel combining high yield strength of min. 380 N/mm 2 (55 KSI) with high resistance to local corrosion and superior resistance to stress corrosion cracking. Ranking the material according to its PRE (pitting resistance equivalent) value, the new alloy fits in between the advanced 6% Mo superaustenitics and the nickel-base Alloy 625 but due to the balanced chemical composition the alloy shows a lot less sensitivity to segregation in the base material as well as in welded structures. It is recommended to weld the material with matching filler. The critical pitting temperature of such joints in the 10% FeCl 3 · 6H 2 O solution is reduced by only 10 C in comparison to the base material. Corrosion tests in artificial seawater (20 g/l Cl - ) with additions of chloride up to 37 g/l as well as in a NaCl-CaCl 2 , solution with 62 g/l Cl - --revealed that the critical pitting temperature does not differentiate from the 6% Mo austenitic steel Alloy 926. With respect to crevice corrosion the depassivation pH value has been determined in 1 M NaCl solution according to Crolet and again there was no difference between Alloy 33 and Alloy 926. SCC tests performed on Alloy 33 in the solution annealed condition as well as after heavy cold work up to R PO,2 ∼ 1,100--1,200 N/mm 2 (160--174 KSI) indicate the high resistance to stress corrosion cracking in hot sodium chloride solutions

  13. Impact of the nanostructuration on the corrosion resistance and hardness of irradiated 316 austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hug, E., E-mail: eric.hug@ensicaen.fr [Laboratoire de Cristallographie et Sciences des Matériaux, Normandie Université, CNRS UMR 6508, 6 Bd Maréchal Juin, 14050 Caen (France); Prasath Babu, R. [School of Materials, University of Manchester, M13 9PL (United Kingdom); Groupe de Physique des Matériaux, UMR CNRS 6634, Université et INSA de Rouen, Normandie Université, Saint-Etienne du Rouvray Cedex (France); Monnet, I. [Centre de recherches sur les Ions, les Matériaux et la Photonique CEA-CNRS, Normandie Université, 6 Bd Maréchal Juin, 14050 Caen (France); Etienne, A. [Groupe de Physique des Matériaux, UMR CNRS 6634, Université et INSA de Rouen, Normandie Université, Saint-Etienne du Rouvray Cedex (France); Moisy, F. [Centre de recherches sur les Ions, les Matériaux et la Photonique CEA-CNRS, Normandie Université, 6 Bd Maréchal Juin, 14050 Caen (France); Pralong, V. [Laboratoire de Cristallographie et Sciences des Matériaux, Normandie Université, CNRS UMR 6508, 6 Bd Maréchal Juin, 14050 Caen (France); Enikeev, N. [Institute of Physics of Advanced Materials, Ufa (Russian Federation); Saint Petersburg State University, Laboratory of the Mechanics of Bulk Nanostructured Materials, 198504 St. Petersburg (Russian Federation); Abramova, M. [Institute of Physics of Advanced Materials, Ufa (Russian Federation); and others

    2017-01-15

    Highlights: • Impacts of nanostructuration and irradiation on the properties of 316 stainless steels are reported. • Irradiation of nanostructured samples implies chromium depletion as than depicted in coarse grain specimens. • Hardness of nanocrystalline steels is only weakly affected by irradiation. • Corrosion resistance of the nanostructured and irradiated samples is less affected by the chromium depletion. - Abstract: The influence of grain size and irradiation defects on the mechanical behavior and the corrosion resistance of a 316 stainless steel have been investigated. Nanostructured samples were obtained by severe plastic deformation using high pressure torsion. Both coarse grain and nanostructured samples were irradiated with 10 MeV {sup 56}Fe{sup 5+} ions. Microstructures were characterized using transmission electron microscopy and atom probe tomography. Surface mechanical properties were evaluated thanks to hardness measurements and the corrosion resistance was studied in chloride environment. Nanostructuration by high pressure torsion followed by annealing leads to enrichment in chromium at grain boundaries. However, irradiation of nanostructured samples implies a chromium depletion of the same order than depicted in coarse grain specimens but without metallurgical damage like segregated dislocation loops or clusters. Potentiodynamic polarization tests highlight a definitive deterioration of the corrosion resistance of coarse grain steel with irradiation. Downsizing the grain to a few hundred of nanometers enhances the corrosion resistance of irradiated samples, despite the fact that the hardness of nanocrystalline austenitic steel is only weakly affected by irradiation. These new experimental results are discussed in the basis of couplings between mechanical and electrical properties of the passivated layer thanks to impedance spectroscopy measurements, hardness properties of the surfaces and local microstructure evolutions.

  14. Corrosion-resistant coating technique for oxide-dispersion-strengthened ferritic/martensitic steel

    International Nuclear Information System (INIS)

    Sakasegawa, Hideo; Tanigawa, Hiroyasu; Ando, Masami

    2014-01-01

    Oxide-dispersion-strengthened (ODS) steels are attractive materials for application as fuel cladding in fast reactors and first-wall material of fusion blanket. Recent studies have focused more on high-chromium ferritic (12-18 wt% Cr) ODS steels with attractive corrosion resistance properties. However, they have poor material workability, require complicated heat treatments for recrystallization, and possess anisotropic microstructures and mechanical properties. On the other hand, low-chromium ferritic/martensitic (8-9 wt% Cr) ODS steels have no such limitations; nonetheless, they have poor corrosion resistance properties. In our work, we developed a corrosion-resistant coating technique for a low-chromium ferritic/martensitic ODS steel. The ODS steel was coated with the 304 or 430 stainless steel, which has better corrosion resistances than the low-chromium ferritic/martensitic ODS steels. The 304 or 430 stainless steel was coated by changing the canning material from mild steel to stainless steel in the conventional material processing procedure for ODS steels. Microstructural observations and micro-hardness tests proved that the stainless steels were successfully coated without causing a deterioration in the mechanical property of the low-chromium ferritic/martensitic ODS steel. (author)

  15. Determination of ferrite formation coefficient of tin in an austenitic stainless steel by the diffusion couple method

    International Nuclear Information System (INIS)

    Marchive, Daniel; Treheux, Daniel; Guiraldenq, Pierre

    1976-01-01

    The ferritic action of tin for a 18-10 stainless steel has been measured by two different methods: the first is based on the diffusion couple method and the graphical representation of compositions in a diagram α/α + γ/γ corresponding to ferrite and austenitic elements of the steel. In the second method, ferrite formation is analyzed in small ingots prepared with different chromium and tin concentrations. Ferrite coefficient of tin, compared to chromium is 0.25 with diffusion couples and this value is in good agreement with the classical method [fr

  16. Iron-nickel-chromium alloys

    International Nuclear Information System (INIS)

    Karenko, M.K.

    1981-01-01

    A specification is given for iron-nickel-chromium age-hardenable alloys suitable for use in fast breeder reactor ducts and cladding, which utilize the gamma-double prime strengthening phase and are characterized in having a delta or eta phase distributed at or near grain boundaries. A range of compositions is given. (author)

  17. Method for electrodeposition of nickel--chromium alloys and coating of uranium

    International Nuclear Information System (INIS)

    Stromatt, R.W.; Lundquist, J.R.

    1975-01-01

    High-quality electrodeposits of nickel-chromium binary alloys in which the percentage of chromium is controlled can be obtained by the addition of a complexing agent such as ethylenediaminetetraacetic disodium salt to the plating solution. The nickel-chromium alloys were found to provide an excellent hydrogen barrier for the protection of uranium fuel elements. (U.S.)

  18. Precipitation and cavity formation in austenitic stainless steels during irradiation

    International Nuclear Information System (INIS)

    Lee, E.H.; Rowcliffe, A.F.; Mansur, L.K.

    1982-01-01

    Microstructural evolution in austenitic stainless steels subjected to displacement damage at high temperature is strongly influenced by the interaction between helium atoms and second phase particles. Cavity nucleation occurs by the trapping of helium at partially coherent particle-matrix interfaces. The recent precipitate point defect collector theory describes the more rapid growth of precipitate-attached cavities compared to matrix cavities where the precipitate-matrix interface collects point defects to augment the normal point deflect flux to the cavity. Data are presented which support these ideas. It is shown that during nickel ion irradiation of a titanium-modified stainless steel at 675 0 C the rate of injection of helium has a strong effect on the total swelling and also on the nature and distribution of precipitate phases. (orig.)

  19. Genotoxic Effects Due to Exposure to Chromium and Nickel Among Electroplating Workers.

    Science.gov (United States)

    El Safty, Amal Mohamed Kamal; Samir, Aisha Mohamed; Mekkawy, Mona Kamal; Fouad, Marwa Mohamed

    Using chromium and nickel for electroplating is important in many industries. This process induces variable adverse health effects among exposed workers. The aim of this study is to detect the genotoxic effects of combined exposure to chromium and nickel among electroplating workers. This study was conducted on 41 male workers occupationally exposed to chromium and nickel in the electroplating section of a factory compared to 41 male nonexposed individuals, where full history and clinical examination were performed. Laboratory investigations included measurement of serum chromium, nickel, 8-hydroxydeoxyguanosine (8-OHdG), and micronuclei were measured in buccal cells. In exposed workers, serum chromium ranged from 0.09 to 7.20 µg/L, serum nickel ranged from 1.20 to 28.00 µg/L, serum 8-OHdG ranged from 1.09 to12.60 ng/mL, and these results were statistically significantly increased compared to nonexposed group ( P electroplating industry are at risk of significant cytogenetic damage.

  20. Freezing controlled penetration of molten metals flowing through stainless steel tubes

    International Nuclear Information System (INIS)

    Sienicki, J.J.; Spencer, B.W.; Vetter, D.L.; Wesel, R.H.

    1985-01-01

    The freezing controlled penetration potential of molten metals flowing within stainless steel structure is important to the safety assessment of hypothetical severe accidents in liquid metal reactors. A series of scoping experiments has been performed in which molten stainless steel and nickel at various initial temperatures and driving pressures were injected downward and upward into 6.4 and 3.3 mm ID stainless steel tubes filled with argon gas and initially at room temperature. In all tests, there was no evidence that the solid tube wall was wetted by the molten metals. The penetration phenomena are markedly different for downward versus upward injections. The dependency upon tube orientation is explained in terms of the absence of wetting. Complete plugs were formed in all experiments halting the continued injection of melt. Calculations with a fluid dynamics/heat transfer computer code show that the injected masses limited by plugging are consistent with freezing through the growth of a stable solidified layer (crust) of metal upon the solid tube wall. 23 refs., 5 figs., 2 tabs

  1. Boron effect on plasticity of austenite chromium-nickel-manganese steel with nitrogen

    International Nuclear Information System (INIS)

    Bulat, S.I.; Sorokina, N.A.; Ul'yanin, E.A.

    1975-01-01

    Plasticity of the stainless steels, with boron content changing from 0 to 0.13% is investigated. It follows from the test results that when the boron content amounts to 0.001 - 0.005%, plasticity of the steel rises at temperatures from 800 to 1000 deg C. When the boron content is higher, plasticity of the steel drops down, particularly at a temperature of 1000 deg C. Due to high sensitivity of the test steel to overheating at temperatures above 1260 deg C, the temperatures of 1240 -1260 deg C are considered to be the optimum for ingot heating, provided that the ingots are preliminarily held at the first stage of heating at a temperature of 1200 - 1220 deg C

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-15

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

  3. The passive oxide films growth on 316L stainless steel in borate buffer solution measured by real-time spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Haisong; Wang, Lu; Sun, Dongbai [National Center for Materials Service Safety (NCMS), University of Science and Technology Beijing, Beijing 100083 (China); Yu, Hongying, E-mail: hyyu@ustb.edu.cn [Institute of Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-10-01

    Highlights: • The optical properties of passive oxide films on 316L stainless steel were studied. • The thickness of the oxide films (1.5–2.6 nm) increased linearly with the potentials. • The growth of passive film followed high electric field ion conduction model. • Selective solubility of oxide induced compositional change of passive film. - Abstract: Passive film growth on 316L stainless steel was investigated in borate buffer electrolyte (pH = 9.1) by real-time spectroscopic ellipsometry (SE) and the composition was estimated by X-ray photoelectron spectroscopy (XPS). Anodic passivation of 316L SS was carried out in the potential range from 0 V{sub SCE} to 0.9 V{sub SCE}, after potentiostatic polarization for 1800s, the current density decayed from 10{sup −2} A cm{sup −2} to 10{sup −6} A cm{sup −2}. The passive film thickness was simulated from Frenel and Drude reflection equations, the average complex refractive index was assumed to be N = 2.3 − j0.445. The estimated thickness increased linearly with potential from 1.5 nm at 0 V to 2.6 nm at 0.8 V. The growth of passive film followed high electric field ion conduction model. The passive film mainly contained the oxide/hydroxide of iron and chromium. The selective solubility of oxide in passive film explained the change of iron and chromium content at different potentials. Few nickel and molybdenum also contributed to the passive film with a constant content.

  4. Development of new high-performance stainless steels

    International Nuclear Information System (INIS)

    Park, Yong Soo

    2002-01-01

    This paper focused on high-performance stainless steels and their development status. Effect of nitrogen addition on super-stainless steel was discussed. Research activities at Yonsei University, on austenitic and martensitic high-performance stainless, steels, and the next-generation duplex stainless steels were introduced

  5. In-service thermal ageing of martensitic stainless steels

    International Nuclear Information System (INIS)

    Tampigny, R.; Molinie, E.; Foct, F.; Dignocourt, P.

    2011-01-01

    Martensitic stainless steels are largely used in Nuclear Power Plants (NPPs) mainly as valve stems, bolts or nuts due to their high mechanical properties and their good resistance to corrosion in primary water. At the end of the eighties, research studies have demonstrated a thermal ageing irreversible embrittlement due to the precipitation of a chromium-rich phase for X6 CrNiCu 17-04, X6 CrNiMo 16.04 and X12 Cr 13 martensitic stainless steels and a semi-empirical modeling has been proposed. Numerous metallurgical examinations have been performed in hot laboratories to consolidate the good correlation between in-service experience and the modeling developed by EDF RD. According to the feedback analysis, thermal ageing embrittlement can appear at different in-service temperatures or do not appear in relation with chemical composition of martensitic stainless steels and end of manufacturing heat treatments associated. A new campaign of metallurgical examinations has been proposed to consolidate previous studies and to contribute to maintenance policy for the next ten years after the third decennial outages for 900 MWe NPP. Influence of real in-service temperatures and end of manufacturing heat treatments have been examined to understand reasons why in some cases thermal ageing embrittlement does not occur or occur with a lowest intensity. These new results have contributed to reinforce EDF RD modeling validity and technical specifications defined in RCC-M for new valve stems, bolts or nuts. (authors)

  6. Effect of nickel and chromium exposure on buccal cells of electroplaters.

    Science.gov (United States)

    Qayyum, Saba; Ara, Anjum; Usmani, Jawed Ahmad

    2012-02-01

    The electroplating industry commonly involves the use of nickel and chromium. An assessment of the genotoxic effects of these metals can be carried out by micronucleus (MN) test in buccal cells. Other nuclear anomalies (NA) observed in buccal cells viz., karyorrhexis, pyknosis and karyolysis are also the indicators of genotoxicity. The current study aims at determining the extent of genotoxic damage in relation to the duration of exposure to nickel and hexavalent chromium via micronuclei induction and other nuclear anomalies. The present investigation included 150 subjects of which 50 individuals with no history of nickel/chromium exposure (Group I) were taken as control, 50 electroplaters exposed to nickel and hexavalent chromium for duration of less than 10 years (Group II) and 50 electroplaters exposed for ≥10 years (Group III) were included. Slides of buccal cells were prepared and the frequency of MN (‰) and NA (‰) were calculated. ANOVA was applied to test significance. Results were considered significant at p exposure increased. Plasma nickel and chromium levels were also determined which showed a positive correlation with frequency MN and other nuclear abnormalities (p < 0.01).

  7. Novel implementation of the use of the EPR-in situ technique (Electrochemical potentiodynamic reactivation) to identify intergranular corrosion susceptability of stainless steels exposed to high temperatures

    International Nuclear Information System (INIS)

    Munoz, N.; Pineda, Y.; Vera, E.; Sepulveda, H.; Heyn, Andreas

    2010-01-01

    Austenitic stainless steels (18 % Cr), are often used in pieces that are exposed to temperatures of 450 o C to 900 o C (heat exchangers). At these temperatures sensibilization occurs on the grain boundaries, becoming a key factor in the appearance of intergranular corrosion. In order to prevent this phenomena from occurring 0.3% to 0.8% of niobium is added as an alloying element in the manufacturing process, which prevents the carbon present in the steel combines with the chromium, avoiding the formation of carbides. An electrochemical method for in-situ application was developed to evaluate the corrosive behavior of stainless steel and its susceptibility and degree of sensibilizaton to an intergranular attack. This work shows the effectiveness of this technique in evaluating niobium's inhibitory effect in preventing the formation of chromium carbides on the grain boundaries of 18% chromium steel, and also shows the technique's potentiality in determining how susceptible these steels are to intercrystalline corrosion

  8. Bioaccumulation of chromium and nickel in the tissues of Barb us ...

    African Journals Online (AJOL)

    1996-04-25

    Apr 25, 1996 ... S, marequensis suggested no serious chromium or nickel pollution in the study area. "To \\~hom . ... The toxicity of chromium and nickel to fish, as individual elements, is ..... its fitness for human consumption). One should also ...

  9. Low temperature sensitization behavior in the weld metal of austenitic stainless steel. Study on low temperature sensitization in weldments of austenitic stainless steels and its improvement by laser surface melting treatment. 1

    International Nuclear Information System (INIS)

    Mori, Hiroaki; Nishimoto, Kazutoshi; Nakao, Yoshikuni

    1996-01-01

    Low temperature sensitization (LTS) behavior in the weld metal of Type308 stainless steel was investigated in this study. Three kinds of Type308 stainless steels, of which carbon contents were 0.04%, 0.06% and 0.08%, were used for this study. TIG welding method was adopted to make the weld metals. Weld metals were subjected to the sensitizing heat treatment in the temperature range between 773 K and 1073 K. The degree of sensitization were examined by the EPR method and the Strauss test. Chromium carbide was absorbed to precipitate at δ/γ grain boundaries in the as-welded weld metals Corrosion test results have shown that the higher carbon content in the weld metal is, the earlier sensitization yields in it. Sensitization in weld metals is found to occur faster than in those solution heat-treated at 1273 K prior to sensitizing heat-treatment. This fact suggests that preexisted chromium carbides have an effect to accelerate sensitization. That is, it is apparent that LTS phenomenon occur even in the weld metal. Moreover, sensitization in the weld metal has occurred in much shorter time than in HAZ, which is attributed to the preferential precipitation of chromium carbide at δ/γ grain boundaries in the weld metals. (author)

  10. Hydrogen damage in stainless steel

    International Nuclear Information System (INIS)

    Caskey, G.R. Jr.

    1981-01-01

    Hydrogen damage has been studied in a wide variety of stainless steels. Both internal and external hydrogen damage were evaluated by ductility or J-integral under rising tensile loads and by fractography. Analysis of the data has emphasized the potential effects of strain-induced martensite on hydrogen damage. Strain-induced martensite was neither necessary nor sufficient for hydrogen damage in the alloys studied. Neither ductility loss nor fracture-mode change correlated generally with martensite formation. Alloy composition, particularly nickel and nitrogen contents, was the primary factor in resistance to hydrogen damage. Thermomechanical processing, however, could alter the degree of hydrogen damage in an alloy and was critical for optimizing resistance to hydrogen damage. 10 figures, 10 tables

  11. Strength of interface in stainless clad steels

    International Nuclear Information System (INIS)

    Ohji, Kiyotsugu; Nakai, Yoshikazu; Hashimoto, Shinji

    1990-01-01

    Mechanical tests were conducted on four kinds of stainless clad steels to establish test methods for determining crack growth resistance of bimaterial interface. In tension tests, smooth specimens and shallow notched specimens were employed. In these tests, all of the smooth specimens were broken in carbon steel, not along the bimaterial interface. On the other hand, most of the shallow notched specimens were broken along the interface, when the notch root was located at the interface. Therefore, the shallow notched specimens were suitable for estimating the strength of the interface in tension tests. For fracture toughness tests, chevron notched specimens are recommended, since pre-fatigue cracks were susceptible to initiate and grow in carbon steel for conventional straight notched specimens. In fatigue crack growth tests, side-grooved and non-side-grooved specimens were employed. Although the side-grooves were machined so that the minimum cross-sectional plane of the specimens coincided with the plane of the bimaterial interface, cracks did not always propagate along the interface. Therefore, the side-grooves were judged not to be effective for cracks to propagate along the bimaterial interface. Both in fracture toughness tests and fatigue tests, the crack growth resistance along bimaterial interface was much lower than the resistance of matrix steels. In all of the mechanical tests conducted, the crack growth resistance along the interface was higher for the normalized material than that for the as-rolled material. The nickel foil inserted between carbon steel and stainless steel improved the growth resistance of interfacial cracks. (author)

  12. Chromium, Nickel and Zinc Levels from Canned and Non-Canned ...

    African Journals Online (AJOL)

    Heavy metals (Chromium, Nickel and Zinc) were determined from both canned and non-canned beverages sold in Samaru, Zaria, Kaduna State, Nigeria. Concentration of Chromium was found to range from 0.528 - 1.509mg/L for canned and 0.176 - 1.358mg/L for non-canned beverages, Nickel concentration was found to ...

  13. Hydrogen effects in stainless steel

    International Nuclear Information System (INIS)

    Caskey, G.R. Jr.

    1983-01-01

    The effects of hydrogen on stainless steels have been reviewed and are summarized in this paper. Discussion covers hydrogen solution and transport in stainless steels as well as the effects of hydrogen on deformation and fracture under various loading conditions. Damage is caused also by helium that arises from decay of the hydrogen isotope tritium. Austenitic, ferritic, martensite, and precipitation-hardenable stainless steels are included in the discussion. 200 references

  14. Characterization of diffusion bonded joint between titanium and 304 stainless steel using a Ni interlayer

    International Nuclear Information System (INIS)

    Kundu, S.; Chatterjee, S.

    2008-01-01

    Solid-state diffusion bonded joints were prepared between commercially pure titanium and 304 stainless steel with nickel as an intermediate material in the temperature range of 800-950 deg. C for 10.8 ks under a 3 MPa uniaxial pressure in vacuum. The interface microstructures and reaction products of the transition joints were investigated by optical and scanning electron microscopy. Up to 850 deg. C processing temperature, a 300-μm nickel interlayer completely restricts the diffusion of titanium to stainless steel. However, the nickel interlayer cannot block the diffusion of Ti to the stainless side and λ + χ + α-Fe, λ + FeTi and λ + FeTi + β-Ti phase mixtures are formed at the SS-Ni interface, when bonding was processed at 900 deg. C and above. These reaction products were confirmed by X-ray diffraction. A maximum tensile strength of ∼ 270 MPa and shear strength of ∼ 194 MPa, along with 6.2% ductility, were obtained for the diffusion bonded joint processed at 850 deg. C. Fracture surface observation in SEM using EDS demonstrates that failure occurred through the Ni-Ti interface of the joints when processed up to 850 deg. C and through the SS-Ni interface when processed at and above 900 deg. C

  15. Diffusion of Nickel into Ferritic Steel Interconnects of Solid Oxide Fuel/Electrolysis Stacks

    DEFF Research Database (Denmark)

    Molin, Sebastian; Chen, Ming; Bowen, Jacob R.

    2013-01-01

    diffusion of nickel from the Ni/YSZ electrode or the contact layer into the interconnect plate. Such diffusion can cause austenization of the ferritic structure and could possibly alter corrosion properties of the steel. Whereas this process has already been recognized by SOFC stack developers, only...... a limited number of studies have been devoted to the phenomenon. Here, diffusion of Ni into ferritic Crofer 22 APU steel is studied in a wet hydrogen atmosphere after 250 hours of exposure at 800 °C using Ni-plated (~ 10 micron thick coatings) sheet steel samples as a model system. Even after...... this relatively short time all the metallic nickel in the coating has reacted and formed solid solutions with iron and chromium. Diffusion of Ni into the steel causes formation of the austenite FCC phase. The microstructure and composition of the oxide scale formed on the sample surface after 250 hours is similar...

  16. Metallurgy and mechanical properties variation with heat input,during dissimilar metal welding between stainless and carbon steel

    Science.gov (United States)

    Ramdan, RD; Koswara, AL; Surasno; Wirawan, R.; Faturohman, F.; Widyanto, B.; Suratman, R.

    2018-02-01

    The present research focus on the metallurgy and mechanical aspect of dissimilar metal welding.One of the common parameters that significantly contribute to the metallurgical aspect on the metal during welding is heat input. Regarding this point, in the present research, voltage, current and the welding speed has been varied in order to observe the effect of heat input on the metallurgical and mechanical aspect of both welded metals. Welding was conducted by Gas Metal Arc Welding (GMAW) on stainless and carbon steel with filler metal of ER 309. After welding, hardness test (micro-Vickers), tensile test, macro and micro-structure characterization and Energy Dispersive Spectroscopy (EDS) characterization were performed. It was observed no brittle martensite observed at HAZ of carbon steel, whereas sensitization was observed at the HAZ of stainless steel for all heat input variation at the present research. Generally, both HAZ at carbon steel and stainless steel did not affect tensile test result, however the formation of chromium carbide at the grain boundary of HAZ structure (sensitization) of stainless steel, indicate that better process and control of welding is required for dissimilar metal welding, especially to overcome this issue.

  17. Structure, mechanical and corrosion properties of powdered stainless steel Kh13

    International Nuclear Information System (INIS)

    Radomysel'skij, I.D.; Napara-Volgina, S.G.; Orlova, L.N.; Apininskaya, L.M.

    1982-01-01

    Structure, mechanical and corrosion properties are studied for compact powdered stainless steel, Grade Kh13, produced from prealloyed powder and a mixture of chromium and iron powders by hot vacuum pressing (HVP) following four schemes: HVP of unsintered billets; HVP of presintered billets; HVP of unsintered billets followed by diffusion annealing; HVP of sintered billets followed by diffusion annealing. Analysis of the structure, mechanical and corrosion properties of Kh13 steel produced according to the four schemes confirmed that production of this steel by the HVP method without presintering of porous billets and diffusion annealing of compact stampings is possible only when prealloyed powder of particular composition is used as a starting material

  18. Effect of composition on corrosion resistance of high-alloy austenitic stainless steel weld metals

    International Nuclear Information System (INIS)

    Marshall, P.I.; Gooch, T.G.

    1993-01-01

    The corrosion resistance of stainless steel weld metal in the ranges of 17 to 28% chromium (Cr), 6 to 60% nickel (Ni), 0 to 9% molybdenum (Mo), and 0.0 to 0.37% nitrogen (N) was examined. Critical pitting temperatures were determined in ferric chloride (FeCl 3 ). Passive film breakdown potentials were assessed from potentiodynamic scans in 3% sodium chloride (NaCl) at 50 C. Potentiodynamic and potentiostatic tests were carried out in 30% sulfuric acid (H 2 SO 4 ) ar 25 C, which was representative of chloride-free acid media of low redox potential. Metallographic examination and microanalysis were conducted on the test welds. Because of segregation of alloying elements, weld metal pitting resistance always was lower than that of matching composition base steel. The difference increased with higher Cr, Mo, and N contents. Segregation also reduced resistance to general corrosion in H 2 SO 4 , but the effect relative to the base steel was less marked than with chloride pitting. Segregation of Cr, Mo, and N in fully austenitic deposits decreased as the Ni' eq- Cr' eq ratio increased. Over the compositional range studied, weld metal pitting resistance was dependent mainly on Mo content and segregation. N had less effect than in wrought alloys. Both Mo and N enhanced weld metal corrosion resistance in H 2 SO 4

  19. Adsorption study of CO and H2O on carbon materials, Ni and stainless steel

    International Nuclear Information System (INIS)

    Kato, S.

    1991-01-01

    Adsorption of CO and water vapor on single crystalline graphite, diamond and an amorphous carbon film at room temperature was investigated by low energy ion scattering (ISS) and compared with stainless steel and nickel surfaces. Even for a CO exposure up to 10 4 L, the C intensity stayed constant and no O peak appeared in the ISS spectra from graphite while Ni and O intensities from Ni surface changed strikingly. Intensities of FE and O signals from stainless steel seriously decrease and increase with increasing exposure of H 2 O, respectively, but did not reach saturation even at an exposure of 10 3 L. On the other hand, C and O intensities from carbon surfaces changed moderately to reach saturation at an exposure of some 100 L. These results indicate that CO and H 2 O do not adsorb significantly on carbon surfaces in contrast to nickel and stainless steel surfaces. As a by-product survival probabilities of scattered He + ions from graphite for the primary energy of 0.6-2 keV were measured to be in a range of 10 -4 to 10 -2 and the survival parameter was deduced to be 5.0 x 10 7 cm s -1 . (author)

  20. Determination of metal ions released by stainless steel arch bar into bio-fluids

    Directory of Open Access Journals (Sweden)

    Lori A. Joseph

    2009-04-01

    Full Text Available The amounts of cobalt, iron, manganese, nickel and chromium ions released from new and reused stainless steel arch bar used for maxillomandibular fixation was determined in Hank’s solutions of different hydrogen and chloride ions concentrations, whole blood serum and phosphate buffered saline (PBS in vitro, over a six-week immersion time at 37 oC, by atomic absorption spectrophotometry. The corrosion levels of the wires due to effects of media and incubation times in the bio-fluids were compared by Duncan’s two-way ANOVA (P less than 0.05. Pearson’s correlation was used in establishing relationship in the amounts of metal ions released by new and reused arch bars. The study indicated that the reused wires released more ions than new ones at all time points. The variation of pH and chloride ions of the bio-fluids had a significant effect on the amount of Ni, Mn and Cr ions released. Ageing prior use of arch bars significantly increased Ni ions released into the bio-fluids.

  1. Transition welds in welding of two-ply steels

    International Nuclear Information System (INIS)

    Fartushnyj, V.G.; Evsyukov, Yu.G.

    1977-01-01

    Studied were physico-mechanical properties of welds made by various welding wires of chromium-nickel and nickel-chromium steels in submerged arc welding of double-layer steels with main layer of the VSt.3sp. carbon steel. It is shown that service-reliable structures welded of two-layer steels are obtained by providing the content from 11 to 20 % Ni in the automatically welded transition layer

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

    Science.gov (United States)

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

    2016-05-01

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

  3. Sensitization Behavior of Type 409 Ferritic Stainless Steel: Confronting DL-EPR Test and Practice W of ASTM A763

    Science.gov (United States)

    Scalise, Taís Campos; de Oliveira, Mara Cristina Lopes; Sayeg, Isaac Jamil; Antunes, Renato Altobelli

    2014-06-01

    Stainless steels employed for manufacturing automotive exhaust systems must withstand severe thermal cycles, corrosive environment due to urea decomposition, and welding operations. AISI 409 ferritic stainless steel can be considered a low-cost alternative for this application. However, depending on the manufacturing conditions during welding cycles, this material can be sensitized due to the precipitation of chromium carbides at grain boundaries. In this work, the intergranular corrosion resistances of the AISI 409 ferritic stainless steel were evaluated after annealing at 300, 500, and 700 °C for 2, 4, and 6 h. Solution-annealed samples were also tested for comparison purposes. Two methodologies were used to assess the sensitization behavior of the 409 stainless steel samples: the first one was based on the ASTM A763 (practice W), while the second one was based on the double-loop electrochemical potentiodynamic reactivation test. It was possible to identify that the annealing treatment performed at 500 °C was more critical to the occurrence of intergranular corrosion.

  4. Intergranular corrosion susceptibility in supermartensitic stainless steel weldments

    Energy Technology Data Exchange (ETDEWEB)

    Aquino, J.M. [Sao Carlos Federal University (UFSCar), Materials Engineering Department, Rodovia Washington Luis, km 235, CEP 13565-905, Sao Carlos, SP (Brazil)], E-mail: dsek@power.ufscar.br; Della Rovere, C.A.; Kuri, S.E. [Sao Carlos Federal University (UFSCar), Materials Engineering Department, Rodovia Washington Luis, km 235, CEP 13565-905, Sao Carlos, SP (Brazil)

    2009-10-15

    The intergranular corrosion susceptibility in supermartensitic stainless steel (SMSS) weldments was investigated by the double loop - electrochemical potentiokinetic reactivation (DL-EPR) technique through the degree of sensitization (DOS). The results showed that the DOS decreased from the base metal (BM) to the weld metal (WM). The heat affected zone (HAZ) presented lower levels of DOS, despite of its complex precipitation mechanism along the HAZ length. Chromium carbide precipitate redissolution is likely to occur due to the attained temperature at certain regions of the HAZ during the electron beam welding (EBW). Scanning electron microscopy (SEM) images showed preferential oxidation sites in the BM microstructure.

  5. Influence of Citric Acid on the Metal Release of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Mazinanian, N.; Wallinder, I. Odnevall; Hedberg, Y. S. [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Stockholm (Sweden)

    2015-08-15

    Knowledge of how metal releases from the stainless steels used in food processing applications and cooking utensils is essential within the framework of human health risk assessment. A new European standard test protocol for testing metal release in food contact materials made from metals and alloys has recently been published by the Council of Europe. The major difference from earlier test protocols is the use of citric acid as the worst-case food simulant. The objectives of this study were to assess the effect of citric acid at acidic, neutral, and alkaline solution pH on the extent of metal release for stainless steel grades AISI 304 and 316, commonly used as food contact materials. Both grades released lower amounts of metals than the specific release limits when they were tested according to test guidelines. The released amounts of metals were assessed by means of graphite furnace atomic absorption spectroscopy, and changes in the outermost surface composition were determined using X-ray photoelectron spectroscopy. The results demonstrate that both the pH and the complexation capacity of the solutions affected the extent of metal release from stainless steel and are discussed from a mechanistic perspective. The outermost surface oxide was significantly enriched in chromium upon exposure to citric acid, indicating rapid passivation by the acid. This study elucidates the effect of several possible mechanisms, including complex ion- and ligand-induced metal release, that govern the process of metal release from stainless steel under passive conditions in solutions that contain citric acid.

  6. Microchemical evolution of neutron-irradiated stainless steel

    International Nuclear Information System (INIS)

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

    1980-04-01

    The precipitates that develop in AISI 316 stainless steel during irradiation play a dominant role in determining the dimensional and mechanical property changes of this alloy. This role is expressed primarily in a large change in matrix composition that alters the diffusional properties of the alloy matrix and also appears to alter the rate of acceptance of point defects at dislocations and voids. The major elemental participants in the evolution have been identified as nickel, silicon, and carbon. The exceptional sensitivity of this evolution to many variables accounts for much of the variability of response exhibited by this alloy in nominally similar irradiations

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

    Science.gov (United States)

    Ishida, Toshihisa; Harayama, Yasuo; Yaguchi, Sinnosuke

    1986-08-01

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

  8. Nickel-chromium-silicon brazing filler metal

    Science.gov (United States)

    Martini, Angelo J.; Gourley, Bruce R.

    1976-01-01

    A brazing filler metal containing, by weight percent, 23-35% chromium, 9-12% silicon, a maximum of 0.15% carbon, and the remainder nickel. The maximum amount of elements other than those noted above is 1.00%.

  9. Irradiated accelerated corrosion of stainless steel

    International Nuclear Information System (INIS)

    Raiman, S.S.; Wang, P.; Was, G.S.

    2015-01-01

    Type 316L stainless steel was exposed to a simulated PWR environment with in-situ proton irradiation to investigate the effect of simultaneous irradiation and corrosion. To enable these experiments, a dedicated beamline was constructed to transport a 3.2 MeV proton beam from a tandem accelerator, through the sample that also acts as the window between the beamline vacuum and a corrosion cell designed to flow primary water at 320 C. degrees and 13.1 MPa. Experiments were conducted on 316L stainless steel samples which were irradiated for 24 hours in 320 C. degrees water with 3 ppm H 2 , at dose rates of 7*10 -6 dpa/s and 7*10 -7 dpa/s, for 4, 24, and 72 hours. A dual-layer oxide formed on the samples, with an inner layer rich in Cr with Fe and Ni content, and an outer layer of Fe oxides. Samples were characterized with TEM (Transmission Electron Microscopy), EDS, and Raman spectroscopy to determine the effect of irradiation. Irradiated samples were found to have a thinner and more porous inner oxide which was deficient in chromium. The outer oxide was found to have significant hematite content, suggesting that irradiation led to an increase in ECP (Electro-Chemical Potential) at the oxide-solution interface, causing accelerated dissolution of the oxide under irradiation. (authors)

  10. High temperature corrosion of nickel alloys by molten calcium chloride in an oxidising environment

    International Nuclear Information System (INIS)

    Barnett, Roger; Gittos, Mike

    2012-09-01

    A series of nickel alloys was submerged in molten calcium chloride (a molten salt proposed for and used in the nuclear industry for a variety of applications), at 850 deg. C for 72 hours under an oxidising environment. The samples were analysed in detail, in order to determine their corrosion behaviour and suitability for use under these conditions. 310 stainless steel was used as a reference material. Extensive corrosion occurred and the observed attack on the metal substrates was general and massive with corrosion rates ranging from 1.17 mm/year, for Haynes 214, to 13.3 mm/year, for 310 stainless steel. All materials showed selective leaching of chromium from the samples but the oxide layer formed was not protective, spalling away easily. The severity of the attack was not immediately visible from the corrosion rate alone: samples showed a friable scale on the surface and deep penetration of the attack beneath, up to 0.63 mm for 310 stainless steel. In some cases, the attack was clearly intergranular with chromium being depleted along the grain boundaries, whereas in others, the attack was more general. No simple correlation between alloying elements and corrosion rate was apparent, with additions of aluminium and silicon appearing to have little or no protective effect. Alloys 600 and Haynes HR-160 showed promise, with relatively low corrosion rates and penetration depths. (authors)

  11. Comparison of galvanic corrosion potential of metal injection molded brackets to that of conventional metal brackets with nickel-titanium and copper nickel-titanium archwire combinations.

    Science.gov (United States)

    Varma, D Praveen Kumar; Chidambaram, S; Reddy, K Baburam; Vijay, M; Ravindranath, D; Prasad, M Rajendra

    2013-05-01

    The aim of the study is to investigate the galvanic corrosion potential of metal injection molding (MIM) brackets to that of conventional brackets under similar in vitro conditions with nickel-titanium and copper nickel-titanium archwires. Twenty-five maxillary premolar MIM stainless steel brackets and 25 conventional stainless steel brackets and archwires, 0.16 inch, each 10 mm length, 25 nickeltitanium wires, 25 copper nickel-titanium wires were used. They were divided into four groups which had five samples each. Combination of MIM bracket with copper nickel-titanium wire, MIM bracket with nickel-titanium wire and conventional stainless steel brackets with copper nickel-titanium wire and conventional stainless steel brackets with nickel-titanium wires which later were suspended in 350 ml of 1 M lactic acid solution media. Galvanic corrosion potential of four groups were analyzed under similar in vitro conditions. Precorrosion and postcorrosion elemental composition of MIM and conventional stainless steel bracket by scanning electron microscope (SEM) with energy dispersive spectroscope (EDS) was done. MIM bracket showed decreased corrosion susceptibility than conventional bracket with copper nickeltitanium wire. Both MIM and conventional bracket showed similar corrosion resistance potential in association with nickel-titanium archwires. It seems that both brackets are more compatible with copper nickel-titanium archwires regarding the decrease in the consequences of galvanic reaction. The EDS analysis showed that the MIM brackets with copper nickel-titanium wires released less metal ions than conventional bracket with copper nickeltitanium wires. MIM brackets showed decreased corrosion susceptibility, copper nickel-titanium archwires are compatible with both the brackets than nickel-titanium archwires. Clinically MIM and conventional brackets behaved more or less similarly in terms of corrosion resistance. In order to decrease the corrosion potential of MIM

  12. Microstructural Characterization and the Effect of Phase Transformations on Toughness of the UNS S31803 Duplex Stainless Steel Aged Treated at 850 °C

    Directory of Open Access Journals (Sweden)

    Zucato Igor

    2002-01-01

    Full Text Available Duplex stainless steels, with ferritic-austenitic microstructure, have excellent mechanical properties and corrosion resistance. However, when duplex stainless steels are exposed to temperatures between 600 and 1000 °C, some phase transformations can occur such as chromium nitrides precipitation, chromium carbides precipitation and the sigma phase formation. The formation of such compounds leads to loss in both corrosion resistance and fracture toughness. The negative effects of the formation of chromium nitrides, carbides and the sigma phase are due to the chromium depletion in the matrix. The phase transformations cited above occur initially at ferritic-austenitic interfaces and at the grain boundaries. The aim of this work is to identify and characterize the phase transformations, which occur when aging heat treatments are carried out at temperatures at which the kinetics is the fastest for the reactions mentioned. At first, the samples were annealed at 1100 °C for 40 min. The aging heat treatments were then carried out at 850 °C for 6, 40 e 600 min. Microstructural characterization was done by using optical microscopy with different etchings, in order to identify each phase formed in the duplex stainless steel during aging heat treatments. The toughness was also evaluated by using Charpy impact test. Impact tests show that loss of toughness was related to phase transformations.

  13. Use of ferritic steels in breeder reactors worldwide

    International Nuclear Information System (INIS)

    Patriarca, P.

    1983-01-01

    The performance of LMFBR reactor steam generator materials is reviewed. Tensile properties of stainless steel-304, stainless steel-316, chromium-molybdenum steels, and Incoloy 800H are presented for elevated temperatures

  14. Development of CSS-42L{trademark}, a high performance carburizing stainless steel for high temperature aerospace applications

    Energy Technology Data Exchange (ETDEWEB)

    Burrier, H.I.; Milam, L. [Timken Co., Canton, OH (United States); Tomasello, C.M.; Balliett, S.A.; Maloney, J.L. [Latrobe Steel Co., Latrobe, PA (United States); Ogden, W.P. [MPB Corp., Lebanon, NH (United States)

    1998-12-31

    Today`s aerospace engineering challenges demand materials which can operate under conditions of temperature extremes, high loads and harsh, corrosive environments. This paper presents a technical overview of the on-going development of CSS-42L (US Patent No. 5,424,028). This alloy is a case-carburizable, stainless steel alloy suitable for use in applications up to 427 C, particularly suited to high performance rolling element bearings, gears, shafts and fasteners. The nominal chemistry of CSS-42L includes: (by weight) 0.12% carbon, 14.0% chromium, 0.60% vanadium, 2.0% nickel, 4.75% molybdenum and 12.5% cobalt. Careful balancing of these components combined with VIM-VAR melting produces an alloy that can be carburized and heat treated to achieve a high surface hardness (>58 HRC at 1mm (0.040 in) depth) with excellent corrosion resistance. The hot hardness of the carburized case is equal to or better than all competitive grades, exceeding 60 HRC at 427 C. The fracture toughness and impact resistance of the heat treated core material have likewise been evaluated in detail and found to be better than M50-NiL steel. The corrosion resistance has been shown to be equivalent to that of 440C steel in tests performed to date.

  15. Effects of high energy nitrogen implantation on stainless steel microstructure

    Science.gov (United States)

    Pelletier, H.; Mille, P.; Cornet, A.; Grob, J. J.; Stoquert, J. P.; Muller, D.

    1999-01-01

    Low energy ion implantation is known to improve chemical and mechanical surface properties of metals. This treatment is often used to enhance wear and corrosion resistance or mechanical life-time of fatigue test of stainless steel or titanium alloys. The aim of this work is to investigate these effects at higher energy, for which deeper (and still not well understood) modifications occur. High fluence (10 18 cm -2) 15N and 14N implantations at 1 MeV have been performed in the 316LL stainless steel and some specimen have been annealed in the 200-500°C temperature range. Nitrogen concentration distribution, structure, morphology and microhardness have been examined with Nuclear Resonance Analysis, Grazing Incidence X-Ray Diffraction and Nanoindentation, respectively. Precipitates of steel and chromium nitride phases and a superficial martensitic transformation can be observed, leading to a significant increase of hardness. The best result is obtained after one hour annealing at 425°C, due to a larger and more homogeneous repartition of nitride species. In this case, a near surface accumulation is observed and explained in terms of diffusion and precipitation mechanisms.

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

    Science.gov (United States)

    Howard, Stanley R [Windsor, SC; Korinko, Paul S [Aiken, SC

    2008-05-27

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

  17. Evaluation of the Sensitization of 316L Stainless Steels After the Post Weld Heat Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Junho; Jang, Changheui [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Lee, Kyoung Soo [Korea Hydro and Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)

    2014-05-15

    It was observed that the PWSCC growth rate of alloy 182 was markedly decreased after PWHT. However, the PWHT of components made of stainless steels (SSs) would be limited because of the concerns about sensitization when they are exposed to temperature range of 500 to 800 .deg. C. Also, the sensitization of austenitic stainless steels could increase the susceptibility to intergrannular stress corrosion cracking. Therefore, the effect of PWHT on the sensitization behaviors of 316L SSs having predominant austenitic structure with small amount of ferrite was investigated to assess the applicability of PWHT to dissimilar weld area with austenitic stainless steels. The sensitization behaviors of two heats of 316L SSs with small amount of ferrite were investigated after heat treatment at 600, 650 and 700 .deg. C. Grain boundary sensitization was not observed in 316L SSs after the heat treatment at 600, 650 and 700 .deg. C up to 30 h. The increase in degree of sensitization (DOS) was caused by reduction of corrosion resistance in ferrite phase due to formation of chromium carbide and intermatallic phases during heat treatment. The DOS value of 316L SSs depended on the ferrite morphology. The stringer type of ferrite (316L-heat A) showed relatively higher DOS in comparison with 316L containing blocky type of ferrite (316L-heat B). It could be due to sufficient supplement of chromium in larger size of ferrite phase.

  18. Evaluation of the Sensitization of 316L Stainless Steels After the Post Weld Heat Treatment

    International Nuclear Information System (INIS)

    Lee, Junho; Jang, Changheui; Lee, Kyoung Soo

    2014-01-01

    It was observed that the PWSCC growth rate of alloy 182 was markedly decreased after PWHT. However, the PWHT of components made of stainless steels (SSs) would be limited because of the concerns about sensitization when they are exposed to temperature range of 500 to 800 .deg. C. Also, the sensitization of austenitic stainless steels could increase the susceptibility to intergrannular stress corrosion cracking. Therefore, the effect of PWHT on the sensitization behaviors of 316L SSs having predominant austenitic structure with small amount of ferrite was investigated to assess the applicability of PWHT to dissimilar weld area with austenitic stainless steels. The sensitization behaviors of two heats of 316L SSs with small amount of ferrite were investigated after heat treatment at 600, 650 and 700 .deg. C. Grain boundary sensitization was not observed in 316L SSs after the heat treatment at 600, 650 and 700 .deg. C up to 30 h. The increase in degree of sensitization (DOS) was caused by reduction of corrosion resistance in ferrite phase due to formation of chromium carbide and intermatallic phases during heat treatment. The DOS value of 316L SSs depended on the ferrite morphology. The stringer type of ferrite (316L-heat A) showed relatively higher DOS in comparison with 316L containing blocky type of ferrite (316L-heat B). It could be due to sufficient supplement of chromium in larger size of ferrite phase

  19. No association between metal allergy and cardiac in-stent restenosis in patients with dermatitis-results from a linkage study

    DEFF Research Database (Denmark)

    Thyssen, Jacob P; Engkilde, Kåre; Menné, Torkil

    2011-01-01

    Background. Percutaneous coronary intervention (PCI) with implantation of a metal stent is a common procedure performed in patients with symptomatic ischaemic heart disease. Intracoronary stents typically have a backbone of stainless steel, which contains nickel, chromium, and molybdenum, and it ......Background. Percutaneous coronary intervention (PCI) with implantation of a metal stent is a common procedure performed in patients with symptomatic ischaemic heart disease. Intracoronary stents typically have a backbone of stainless steel, which contains nickel, chromium, and molybdenum......, and it remains unclear whether individuals who are allergic to these metals have an increased risk of restenosis after PCI with stent implantation. Objectives. To further evaluate whether dermatitis patients with nickel and/or chromium allergy had an increased risk of developing cardiac in-stent restenosis...... with stainless steel stents. Methods. An individual-level linkage study was performed to identify dermatitis patients who had been patch tested with the European baseline series between 1979 and 2007 at Gentofte University Hospital (N = 18794) and who had also undergone PCI at some point in a Danish hospital...

  20. Study of corrosion resistance of AISI 444 ferritic stainless steel for application as a biomaterial; Estudo da resistencia a corrosao do aco inoxidavel ferritico AISI 444 para aplicacao como biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Rogerio Albuquerque

    2014-09-01

    Ferritic stainless steels are ferromagnetic materials. This property does not allow their use in orthopedic prosthesis. Nevertheless, in some specific applications, this characteristic is very useful, such as, for fixing dental and facial prostheses by using magnetic attachments. In this study, the corrosion resistance and cytotoxicity of the AISI 444 ferritic stainless steel, with low nickel content, extra-low interstitial levels (C and N) and Ti and Nb stabilizers, were investigated for magnetic dental attachments application. The ISO 5832-1 (ASTM F-139) austenitic stainless steel and a commercial universal keeper for dental attachment (Neo-magnet System) were evaluated for comparison reasons. The first stainless steel is the most used metallic material for prostheses, and the second one, is a ferromagnetic keeper for dental prostheses (NeoM). In vitro cytotoxicity analysis was performed by the red neutral incorporation method. The results showed that the AISI 444 stainless steel is non cytotoxic. The corrosion resistance was studied by anodic polarization methods and electrochemical impedance spectroscopy (EIS), in a saline phosphate buffered solution (PBS) at 37 °C. The electronic properties of the passive film formed on AISI 444 SS were evaluated by the Mott-Schottky approach. All tested materials showed passivity in the PBS medium and the passive oxide film presented a duplex nature. The highest susceptibility to pitting corrosion was associated to the NeoM SS. This steel was also associated to the highest dopant concentration. The comparatively low levels of chromium (nearly 12.5%) and molybdenum (0.3%) of NeoM relatively to the other studied stainless steels are the probable cause of its lower corrosion resistance. The NeoM chemical composition does not match that of the SUS444 standards. The AISI 444 SS pitting resistance was equivalent to the ISO 5832-1 pointing out that it is a potential candidate for replacement of commercial ferromagnetic alloys used

  1. Effect of Aging on Precipitation Behavior and Pitting Corrosion Resistance of SAF2906 Super Duplex Stainless Steel

    Science.gov (United States)

    Li, Jianchun; Li, Guoping; Liang, Wei; Han, Peide; Wang, Hongxia

    2017-09-01

    The effect of aging temperature and holding time on the precipitation of secondary phases and pitting corrosion resistance of SAF2906 super duplex stainless steel was examined. Chromium nitride and σ phase were observed to preferentially precipitate at the ferrite/austenite interface. An amount of nitrides was also observed within the ferrite grain. The precipitation of chromium nitride occurred before the σ phase. The increase in aging temperature and holding time did not affect the concentration of the nitrides but increased the area fraction of the σ phase at a faster rate. The Cr2N precipitation in SAF2906 is more evident than that of the other duplex stainless steels. The variation tendency of the precipitation concentrations is primarily consistent with the prediction results of Thermo-Calc software. The electrochemical results showed that Cr2N and σ phase significantly reduced the pitting potential. Scanning electron microscope observations revealed that pits appear mainly in regions adjacent to sigma phase and Cr2N.

  2. Characterization of sensitization and stress corrosion cracking behavior of stabilized stainless steels under BWR conditions

    International Nuclear Information System (INIS)

    Kilian, R.; Ilg, U.; Meier, V.; Teichmann, H.; Wachter, O.

    1995-01-01

    Stress corrosion cracking occurs if the three parameters -- material condition, tensile stress and water chemistry -- are in a critical range. In this study the material conditions especially of Ti- and Nb-stabilized steels are considered. The purpose of this work is to show the influence of the degree of sensitization of Ti- and Nb-stabilized stainless steels on stress corrosion cracking susceptibility in BWR water chemistry. This is an on-going research program. Preliminary results will be presented. Different types of stabilized, and for comparison unstabilized, stainless steels are examined in various heat treatment conditions with regard to their sensitization behavior by EPR tests (double loop) and TEM. The results are plotted in sensitization diagrams. The sensitization behavior depends on many parameters such as carbon content, stabilization element, stabilization ratio and materials history, e.g. solution heat treatment or cold working. The obtained EPR sensitization diagrams are compared with the well known sensitization diagrams from the literature, which were determined by standard IC test according to e.g. German standard DIN 50914 (equivalent to ASTM A 262, Pract. E). Based on the obtained EPR sensitization diagrams material conditions for SSRT tests were selected. The EPR values (Ir/Ia x 100%) of the tested Ti-stabilized stainless steel are in the range of ∼ 0.1--20%. The SSRT tests are carried out in high-temperature water with 0.4 ppm O 2 , a conductivity of 0.5 microS/cm and a strain rate of 1x10 -6-1 . The test temperature is 280 C. Ti-stabilized stainless steel with Ir/Ia x 100% > 1% suffered intergranular stress corrosion cracking under these conditions. The SCC tests for Nb-stabilized stainless steel are still in progress. The correlation between EPR value, chromium depletion and SSRT result will be shown for a selected material condition of sensitized Ti-stabilized stainless steel

  3. Thermal stability of manganese-stabilized stainless steels

    International Nuclear Information System (INIS)

    Klueh, R.L.; Kenik, E.A.

    1993-01-01

    Previous work on a series of experimental high-manganese reduced-activation austenitic stainless steels demonstrated that they have improved tensile properties relative to type 316 stainless steel in both the annealed and 20% cold-worked conditions. Steels were tested with an Fe-20Mn-12Cr-0.25C (in weight percent) base composition, to which various combinations of Ti, W, V, P, and B were added. Tensile tests have now been completed on these steels after thermal aging at 600 degrees C. Thermal stability varied with composition, but the alloys were as stable or more stable than type 316 stainless steel. the strength of the annealed steels increased slightly after aging to 5000 h, while a strength decrease occurred for the cold worked steel. In both conditions, a steel containing a combination of all the alloying elements was most stable and had the best strength after thermal aging 5000 h at 600 degrees C. Despite having much higher strength than 316 stainless steel after aging, the ductility of the strongest experimental alloy was still as good as that of 316 stainless steel

  4. Hydrogen Embrittlement Mechanism in Fatigue Behaviour of Austenitic and Martensitic Stainless Steels

    Directory of Open Access Journals (Sweden)

    Brück Sven

    2018-01-01

    Full Text Available In the present study, the influence of hydrogen on the fatigue behaviour of the high strength martensitic stainless steel X3CrNiMo13-4 and the metastable austenitic stainless steels X2Crni19-11 with various nickel contents was examined in the low and high cycle fatigue regime. The focus of the investigations was the changes in the mechanisms of short crack propagation. The aim of the ongoing investigation is to determine and quantitatively describe the predominant processes of hydrogen embrittlement and their influence on the short fatigue crack morphology and crack growth rate. In addition, simulations were carried out on the short fatigue crack growth, in order to develop a detailed insight into the hydrogen embrittlement mechanisms relevant for cyclic loading conditions.

  5. Spinodal decomposition mechanism study on the duplex stainless steel UNS S31803 using ultrasonic speed measurements

    International Nuclear Information System (INIS)

    Albuquerque, Victor Hugo C. de; Macedo Silva, Edgard de; Pereira Leite, Josinaldo; Pindo de Moura, Elineudo; Araujo Freitas, Vera Lucia de; Tavares, Joao Manuel R.S.

    2010-01-01

    This work, focuses on the spinodal decomposition mechanism study on the duplex stainless steel duplex UNS S31803, composed by austenite (γ) and ferrite (α) phases, at 425 o C and 475 o C temperatures by ultrasonic speed measurements. This temperature range is responsible for the transformation mechanism of α initial phase to α phases (poor in chromium) and α' (rich in chromium) by spinodal decomposition. The techniques to accomplish this analysis are based mainly on X-ray diffraction measures and ultrasonic speed. The obtained results show that it is possible to conclude that the use of ultrasonic speed measurements indicates a promising technique for following-up the phase transformation and spinodal decomposition on the steel studied.

  6. Hydrogen Embrittlement Mechanism in Fatigue Behavior of Austenitic and Martensitic Stainless Steels

    Directory of Open Access Journals (Sweden)

    Sven Brück

    2018-05-01

    Full Text Available In the present study, the influence of hydrogen on the fatigue behavior of the high strength martensitic stainless steel X3CrNiMo13-4 and the metastable austenitic stainless steels X2Crni19-11 with various nickel contents was examined in the low and high cycle fatigue regime. The focus of the investigations were the changes in the mechanisms of short crack propagation. Experiments in laboratory air with uncharged and precharged specimen and uncharged specimen in pressurized hydrogen were carried out. The aim of the ongoing investigation was to determine and quantitatively describe the predominant processes of hydrogen embrittlement and their influence on the short fatigue crack morphology and crack growth rate. In addition, simulations were carried out on the short fatigue crack growth, in order to develop a detailed insight into the hydrogen embrittlement mechanisms relevant for cyclic loading conditions. It was found that a lower nickel content and a higher martensite content of the samples led to a higher susceptibility to hydrogen embrittlement. In addition, crack propagation and crack path could be simulated well with the simulation model.

  7. Synergistic Effect of Nitrogen and Molybdenum on Localized Corrosion of Stainless Steels

    International Nuclear Information System (INIS)

    Kim, Y. S.

    2010-01-01

    According to the bipolar model, ion selectivity of some species in the passive film is important factor to control the passivation. An increase of cation selectivity of outer layer of the passive film can stabilize the film and improves the corrosion resistance. Therefore, the formation and roles of ionic species in the passive film should be elucidated. In this work, two types of solution (hydrochloric or sulfuric acid) were used to test high N and Mo-bearing stainless steels. The objective of this work was to investigate the formation of oxyanions in the passive film and the roles of oxyanions in passivation of stainless steel. Nitrogen exists as atomic nitrogen, nitric oxide, nitro-oxyanions (NO x - ), and N-H species, not nitride in the passive film. Because of its high mobility, the enriched atomic nitrogen can act as a reservoir. The formation of N-H species buffers the film pH and facilitates the formation of oxyanions in the film. NO x - species improve the cation selectivity of the film, increasing the oxide content and film density. NO x - acts similar to a strong inhibitor both in the passive film and at active sites. This facilitates the formation of chromium oxide. Also, NO x - can make more molybdate and nitric oxide by reacting with Mo. The role of Mo addition on the passivation characteristics of stainless steel may differ with the test environment. Mo exists as metallic molybdenum, Molybdenum oxide, and molybdate and the latter facilitates the oxide formation. When nitrogen and molybdenum coexist in stainless steel, corrosion resistance in chloride solutions is drastically increased. This synergistic effect of N and Mo in a chloride solution is mainly due to the formation of nitro-oxyanions and molybdate ion. Oxyanions can be formed by a 'solid state reaction' in the passive film, resulting in the formation of more molybdate and nitric oxide. These oxyanions improve the cation selectivity of the outer layer and from more oxide and increase the

  8. Plastic strain characterization in austenitic stainless steels and nickel alloys by electron backscatter diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Saez-Maderuelo, A., E-mail: alberto.saez@ciemat.es [CIEMAT, Av. Complutense, 22-28040 Madrid (Spain); Castro, L.; Diego, G. de [CIEMAT, Av. Complutense, 22-28040 Madrid (Spain)

    2011-09-01

    Stress corrosion cracking (SCC) is enhanced by cold work and causes many problems in components of the nuclear power plants. Besides, during manufacturing, installation, welding and service of the material, residual strains can be produced increasing the susceptibility to SCC. For this reason, it is important to characterize the degree of plastic strain due to dislocation accumulation in each crystal. Electron backscatter diffraction (EBSD), in conjunction with scanning electron microscope (SEM), has been a great advance in this field because it enables to estimate the plastic strain in a quick and easy way. Nevertheless, over the last few years, a lot of different mathematical expressions to estimate the plastic strain have appeared in the literature. This situation hinders the election of one of them by a novel scientist in this field. Therefore, in this paper some of the more common expressions used in the calculation of the angular misorientation have been presented and discussed in order to clarify their more important aspects. Then, using one of these expressions (average local misorientation), curves relating misorientation density with known levels of strain will be obtained for an austenitic stainless steel 304L and nickel base alloy 690, which have shown a linear behaviour that is in good agreement with results found in the literature. Finally, using curves obtained in previous steps, levels of plastic strain in a plate of nickel base alloy 600 welded with weld metal 182 were estimated between 8 and 10% for a high temperature mill annealing sample.

  9. Plastic strain characterization in austenitic stainless steels and nickel alloys by electron backscatter diffraction

    International Nuclear Information System (INIS)

    Saez-Maderuelo, A.; Castro, L.; Diego, G. de

    2011-01-01

    Stress corrosion cracking (SCC) is enhanced by cold work and causes many problems in components of the nuclear power plants. Besides, during manufacturing, installation, welding and service of the material, residual strains can be produced increasing the susceptibility to SCC. For this reason, it is important to characterize the degree of plastic strain due to dislocation accumulation in each crystal. Electron backscatter diffraction (EBSD), in conjunction with scanning electron microscope (SEM), has been a great advance in this field because it enables to estimate the plastic strain in a quick and easy way. Nevertheless, over the last few years, a lot of different mathematical expressions to estimate the plastic strain have appeared in the literature. This situation hinders the election of one of them by a novel scientist in this field. Therefore, in this paper some of the more common expressions used in the calculation of the angular misorientation have been presented and discussed in order to clarify their more important aspects. Then, using one of these expressions (average local misorientation), curves relating misorientation density with known levels of strain will be obtained for an austenitic stainless steel 304L and nickel base alloy 690, which have shown a linear behaviour that is in good agreement with results found in the literature. Finally, using curves obtained in previous steps, levels of plastic strain in a plate of nickel base alloy 600 welded with weld metal 182 were estimated between 8 and 10% for a high temperature mill annealing sample.

  10. Corrosion behaviour of laser clad stainless steels

    International Nuclear Information System (INIS)

    Damborenea, J.J. de; Weerasinghe, V.M.; West, D.R.F.

    1993-01-01

    The present paper is focussed in the study of the properties of a clad layer of stainless steel on a mild steel. By blowing powder of the alloy into a melt pool generated by a laser of 2 KW, an homogeneous layer of 316 stainless steel can be obtained. Structure, composition and corrosion behaviour are similar to those of a stainless steel in as-received condition. (Author)

  11. Stress corrosion cracking for 316 stainless steel clips in a condensate stabilizer

    Energy Technology Data Exchange (ETDEWEB)

    Al-Awar, A.; Aldajah, S.; Harhara, A. [Department of Mechanical Engineering, United Arab Emirates University, P. O. Box 17555 Al-AIn 17555 (United Arab Emirates)

    2011-09-15

    In one of the gas processing facilities in Abu Dhabi, UAE; a case of 316L stainless steel material failure occurred in the fractionating column due to stress cracking corrosion twice in a cycle of less than 2 years. This paper studies the stress corrosion cracking behavior of the 316L stainless steel in an accelerated corrosion environment and compares it with a higher corrosion resistant nickel alloy (Inconel 625). The experimental work was designed according to ASTM G36 standard, the samples were immersed in a boiling magnesium chloride medium which provided the accelerated corrosion environment and the tested samples were shaped into U-bend specimens as they underwent both plastic and elastic stresses. The specimens were then tested to determine the time required for cracks to initiate. The results of the experimental work showed that the main mode of failure was stress corrosion cracking initiated by the proven presence of chlorides, hydrogen sulfide, and water at elevated temperatures. Inconel 625 samples placed in the controlled environment showed better corrosion resistance as it took them an average of 56 days to initiate cracks, whereas it took an average of 24 days to initiate cracks in the stainless steel 316L samples. The scanning electron microscopy (SEM) micrographs showed that the cracks in the stainless steel 316L samples were longer, wider, and deeper compared to the cracks of Inconel 625. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Influence of nitrogen in the shielding gas on corrosion resistance of duplex stainless steel welds

    Science.gov (United States)

    Bhatt, R. B.; Kamat, H. S.; Ghosal, S. K.; de, P. K.

    1999-10-01

    The influence of nitrogen in shielding gas on the corrosion resistance of welds of a duplex stainless steel (grade U-50), obtained by gas tungsten arc (GTA) with filler wire, autogenous GTA (bead-on-plate), electron beam welding (EBW), and microplasma techniques, has been evaluated in chloride solutions at 30 °C. Pitting attack has been observed in GTA, electron beam welding, and microplasma welds when welding has been carried out using pure argon as the shielding gas. Gas tungsten arc welding with 5 to 10% nitrogen and 90 to 95% argon, as the shielding gas, has been found to result in an improved pitting corrosion resistance of the weldments of this steel. However, the resistance to pitting of autogenous welds (bead-on-plate) obtained in pure argon as the shielding gas has been observed to remain unaffected. Microscopic examination, electron probe microanalysis (EPMA), and x-ray diffraction studies have revealed that the presence of nitrogen in the shielding gas in the GTA welds not only modifies the microstructure and the austenite to ferrite ratio but also results in a nearly uniform distribution of the various alloying elements, for example, chromium, nickel, and molybdenum among the constitutent phases, which are responsible for improved resistance to pitting corrosion.

  13. Microstructure and Hardness of High Temperature Gas Nitrided AISI 420 Martensitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Ibrahim Nor Nurulhuda Md.

    2014-07-01

    Full Text Available This study examined the microstructure and hardness of as-received and nitrided AISI 420 martensitic stainless steels. High temperature gas nitriding was employed to treat the steels at 1200°C for one hour and four hours using nitrogen gas, followed by furnace cooled. Chromium nitride and iron nitride were formed and concentrated at the outmost surface area of the steels since this region contained the highest concentration of nitrogen. The grain size enlarged at the interior region of the nitrided steels due to nitriding at temperature above the recrystallization temperature of the steel and followed by slow cooling. The nitrided steels produced higher surface hardness compared to as-received steel due to the presence of nitrogen and the precipitation of nitrides. Harder steel was produced when nitriding at four hours compared to one hour since more nitrogen permeated into the steel.

  14. Welding Metallurgy and Weldability of Stainless Steels

    Science.gov (United States)

    Lippold, John C.; Kotecki, Damian J.

    2005-03-01

    Welding Metallurgy and Weldability of Stainless Steels, the first book in over twenty years to address welding metallurgy and weldability issues associated with stainless steel, offers the most up-to-date and comprehensive treatment of these topics currently available. The authors emphasize fundamental metallurgical principles governing microstructure evolution and property development of stainless steels, including martensistic, ferric, austenitic, duplex, and precipitation hardening grades. They present a logical and well-organized look at the history, evolution, and primary uses of each stainless steel, including detailed descriptions of the associated weldability issues.

  15. Stainless Steel to Titanium Bimetallic Transitions

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

  16. Aging degradation of cast stainless steel

    International Nuclear Information System (INIS)

    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 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 α' 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 0 C. The existing correlations do not accurately represent the embrittlement behavior over the temperature range 300 to 450 0 C. 18 refs., 13 figs

  17. Dynamical recrystallization of high purity austenitic stainless steels; Recristallisation dynamique d'aciers inoxydables austenitiques de haute purete

    Energy Technology Data Exchange (ETDEWEB)

    Gavard, L

    2001-01-01

    The aim of this work is to optimize the performance of structural materials. The elementary mechanisms (strain hardening and dynamical regeneration, germination and growth of new grains) occurring during the hot working of metals and low pile defect energy alloys have been studied for austenitic stainless steels. In particular, the influence of the main experimental parameters (temperature, deformation velocity, initial grain size, impurities amount, deformation way) on the process of discontinuous dynamical recrystallization has been studied. Alloys with composition equal to those of the industrial stainless steel-304L have been fabricated from ultra-pure iron, chromium and nickel. Tests carried out in hot compression and torsion in order to cover a wide range of deformations, deformation velocities and temperatures for two very different deformation ways have allowed to determine the rheological characteristics (sensitivity to the deformation velocity, apparent activation energy) of materials as well as to characterize their microstructural deformations by optical metallography and electron back-scattered diffraction. The influence of the initial grain size and the influence of the purity of the material on the dynamical recrystallization kinetics have been determined. An analytical model for the determination of the apparent mobility of grain boundaries, a semi-analytical model for the dynamical recrystallization and at last an analytical model for the stationary state of dynamical recrystallization are proposed as well as a new criteria for the transition between the refinement state and the state of grain growth. (O.M.)

  18. Use of tracer techniques for studying the influence of addition elements and crystallographic parameters on intergranular diffusion in austenitic stainless steels

    International Nuclear Information System (INIS)

    Assassa, Wafaa.

    1975-01-01

    16% chromium, 14% nickel stainless steel, austenitic at all temperatures, covers a wide field of industrial use. Its behavior was studied in order to find out more about how impurities affect the three basic elements forming the solid solution. After a review of some general properties (segregation, precipitation, migration, structure and energy of boundaries) the physico-chemical aspect of the grain boundaries was investigated. The atomic diffusion rates of the three basic elements forming the solid-solution were compared in order to evaluate their mutual kinetics and the effects of impurities such as C, Si or addition elements such as Ni were studied. The radiotracer technique was used ( 59 Fe, 51 Cr, 63 Ni). The structural aspect of the grain boundaries of this type of steel was then examined by analyzing the self-diffusion of iron in preoriented bicrystals and considering the properties of the boundaries parallel with and perpendicular to the (001) bending axis. A study was devoted to the effect of a new structural parameter, asymmetry of the grain boundaries, little analyzed in diffusion [fr

  19. Effect of Solution Annealing on Susceptibility to Intercrystalline Corrosion of Stainless Steel with 20% Cr and 8% Ni

    Science.gov (United States)

    Taiwade, R. V.; Patil, A. P.; Patre, S. J.; Dayal, R. K.

    2013-06-01

    In general, as-received (AR) austenitic stainless steels (ASSs) contain complex carbide precipitates due to manufacturing operations, subsequent annealing treatment, or due to the fabrication processes such as welding. The presence of pre-existing carbides leads to cumulative sensitization and make the steel susceptible to intercrystalline corrosion (ICC)/intergranular corrosion (IGC) which causes premature failure during service. Solution annealing (SA) is one of the ways to deal with such situations. In this present investigation, the AR (hot rolled and mill annealed) chromium-nickel (Cr-Ni) ASS is compared with SA Cr-Ni ASS. The extent of ICC/IGC was evaluated qualitatively and quantitatively by various electrochemical tests including ASTM standard A-262 Practice A and Practice E, double loop electrochemical potentiokinetic reactivation and electrochemical impedance spectroscopy. The degree of sensitization for hot rolled mill annealed AR condition is found to be substantially higher (51.55%) than that of SA condition (26.9%) for thermally aged samples (at 700 °C). The chemical composition across the grain boundary was measured using electron probe micro-analyzer for both (AR and SA) conditions and confirms that the pre-sensitization effect was completely removed after SA treatment.

  20. Investigation of the Effects of Solution Temperature on the Corrosion Behavior of Austenitic Low-Nickel Stainless Steels in Citric Acid using Impedance and Polarization Measurements

    Directory of Open Access Journals (Sweden)

    Mulimbayan Francis M.

    2015-01-01

    Full Text Available Stainless steels may be classified according to alloy microstructure – ferritic, austenitic, martensitic, duplex, and precipitation hardening grades. Among these, austenitic grade has the largest contribution to market due to the alloy’s numerous industrial and domestic applications. In this study, the corrosion behavior of low-Nickel stainless steel in citric acid was investigated using potentiodynamic polarization techniques and Electrochemical Impedance Spectroscopy (EIS. The corrosion current density which is directly related to corrosion rate was extracted from the generated anodic polarization curve. Increasing the temperature of the citric acid resulted to increased corrosion current densities indicating higher corrosion rates at initial corrosion condition. EIS was performed to generate Nyquist plots whose shape and size depicts the corrosion mechanism and corrosion resistance of the alloy in citric acid, respectively. All the generated Nyquist plots have depressed semi-circle shapes implying that corrosion process takes place with charge-transfer as the rate-determining step. Based from the extracted values of polarization resistance (Rp, the temperature of the solution has negative correlation with the corrosion resistance of the studied alloy.

  1. IGSCC in cold worked austenitic stainless steel in BWR environment

    International Nuclear Information System (INIS)

    Persson, B.; Lindblad, B.

    1989-09-01

    The survey shows that austenitic stainless steels in a cold worked condition can exhibit IGSCC in BWR environment. It is also found that IGSCC often is initiated as a transgranular crack. Local stresses and surface defects very often acts as starting points for IGSCC. IGSCC due to cold working requires a cold working magnitude of at leas 5%. During cold working a formation of mechanical martensite can take place. The transgranular corrosion occurs in the martensitic phase due to sensitation. The crack propagates integranularly due to anodic solvation of α'-martensite. Sensitation of the martensitic phase is fasten in BCC-structures than in a FCC-structures mainly due to faster diffusion of chromium and carbon which cause precipitation of chromium carbides. Experiments show that a carbon content as low as 0.008% is enough for the formation of 68% martensite and for sensitation. Hydrogen induced cracking is regarded as a mechanism which can accelerate IGSCC. Such cracking requires a hydrostatic stress near the crack tip. Since the oxide in the crack tip is relatively impermeable to hydrogen, cracks in the oxide layer are required for such embrittlement. Hydrogen induced embrittlement of the martensitic phase, at the crack tip, can cause crack propagation. Solution heat treated unstabilized stainless steels are regarded to have a good resistance to IGSCC if they have not undergone cold working. In general, though, Mo-alloyed steels have a better resistance to IGSCC in BWR environment. Regarding the causes for IGSCC, the present literature survey shows that many mechanisms are suggested. To provide a safer ground for the estimation of crack propagation rates, SA recommends SKI to finance a project with the aim to determine the crack propagation rate on proper material. (authors) (65 refs.)

  2. Standard test method for evaluating stress-corrosion cracking of stainless alloys with different nickel content in boiling acidified sodium chloride solution

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This test method describes a procedure for conducting stress-corrosion cracking tests in an acidified boiling sodium chloride solution. This test method is performed in 25% (by mass ) sodium chloride acidified to pH 1.5 with phosphoric acid. This test method is concerned primarily with the test solution and glassware, although a specific style of U-bend test specimen is suggested. 1.2 This test method is designed to provide better correlation with chemical process industry experience for stainless steels than the more severe boiling magnesium chloride test of Practice G36. Some stainless steels which have provided satisfactory service in many environments readily crack in Practice G36, but have not cracked during interlaboratory testing using this sodium chloride test method. 1.3 This boiling sodium chloride test method was used in an interlaboratory test program to evaluate wrought stainless steels, including duplex (ferrite-austenite) stainless and an alloy with up to about 33% nickel. It may also b...

  3. Chemical decontamination of stainless steel

    International Nuclear Information System (INIS)

    Onuma, Tsutomu; Akimoto, Hidetoshi

    1991-01-01

    The present invention concerns a method for chemical decontamination of radioactive metal waste materials contaminated with radioactive materials on the surface, generated in radioactive materials-handling facilities. The invention is comprised of a method of chemical decontamination of stainless steel, characterized by comprising a first process of immersing a stainless steel-based metal waste material contaminated by radioactive materials on the surface in a sulfuric acid solution and second process of immersing in an aqueous solution of sulfuric acid and oxidizing metal salt, in which a portion of the surface of the stainless steel to be decontaminated is polished mechanically to expose a portion of the base material before the above first and second processes. 1 figs., 2 tabs

  4. Changes of surface structure of Ni, W and chromium-nickel steel Cr18Ni10 irradiated by high fluences of krypton ions with high energies

    International Nuclear Information System (INIS)

    Didyk, A.Yu.; Semina, V.K.; Khalil, A.; Suvorov, A.L.; Stepanov, A.Eh.; Cheblukov, Yu.N.

    1999-01-01

    The surfaces of W single crystal, Ni polycrystal and chromium-nickel steel, irradiated by Kr ions with energy 305 and 245 MeV up to the fluences 2*10 15 and 3*10 15 ion/cm 2 , were studied by means of scanning electron microscopy. The evaporation coefficients of material surfaces were estimated on the base of changes of surface relief. The values of these coefficients turned out much more than ones predicted by the inelastic sputtering model. The method of 'step' was offered and realized for the more correct estimations evaporation coefficient on the Ni example. The phenomenological model explaining the observed phenomena is introduced

  5. Stainless steels low temperature nitriding

    International Nuclear Information System (INIS)

    Roux, T.; Darbeida, A.; Von Stebut, J.; Michel, H.; Lebrun, J.P.; Hertz, D.

    1995-01-01

    Nitrogen ions implantation of 316L stainless steel leads to monophasic diffusion layers, which are constituted of a solid solution (γ N ) fcc, metastable, nitrogen sur-saturated, and without order. This article shows that for 316L stainless steels,these layers improve the tribological properties without degradation of the corrosion resistance. (A.B.). 13 refs. 6 figs

  6. Semiconducting properties of oxide and passive films formed on AISI 304 stainless steel and Alloy 600

    Directory of Open Access Journals (Sweden)

    Ferreira M. G. S.

    2002-01-01

    Full Text Available The semiconducting properties of passive films formed on AISI 304 stainless steel and Alloy 600 in borate buffer solution were studied by capacitance (Mott-Schottky approach and photocurrent measurements. Oxide films formed on 304 stainless steel in air at 350 ºC have also been studied. The results obtained show that, in all cases the electronic structure of the films is comparable to that of a p-n heterojunction in which the space charges developed at the metal-film and film-electrolyte interfaces have also to be considered. This is in accordance with analytical results showing that the oxide films are in all cases composed of an inner region rich in chromium oxide and an outer region rich in iron oxide.

  7. 76 FR 87 - Grant of Authority for Subzone Status; ThyssenKrupp Steel and Stainless USA, LLC; (Stainless and...

    Science.gov (United States)

    2011-01-03

    ... at the stainless and carbon steel products manufacturing facility of ThyssenKrupp Steel and Stainless... to the manufacturing of stainless and carbon steel products at the facility of ThyssenKrupp Steel and... Status; ThyssenKrupp Steel and Stainless USA, LLC; (Stainless and Carbon Steel Products) Calvert, AL...

  8. Stainless steel fabrications: past and present

    International Nuclear Information System (INIS)

    Daniels, R.

    1986-01-01

    The paper deals with stainless steel fabrications of Fairey Engineering Company for the nuclear industry. The manufacture of stainless steel containers for Magnox and Advanced Gas Cooled Reactors, flexible fabrication facility, and welding development, are all briefly described. (U.K.)

  9. Quantitative Evaluation of Aged AISI 316L Stainless Steel Sensitization to Intergranular Corrosion: Comparison Between Microstructural Electrochemical and Analytical Methods

    Science.gov (United States)

    Sidhom, H.; Amadou, T.; Sahlaoui, H.; Braham, C.

    2007-06-01

    The evaluation of the degree of sensitization (DOS) to intergranular corrosion (IGC) of a commercial AISI 316L austenitic stainless steel aged at temperatures ranging from 550 °C to 800 °C during 100 to 80,000 hours was carried out using three different assessment methods. (1) The microstructural method coupled with the Strauss standard test (ASTM A262). This method establishes the kinetics of the precipitation phenomenon under different aging conditions, by transmission electronic microscope (TEM) examination of thin foils and electron diffraction. The subsequent chromium-depleted zones are characterized by X-ray microanalysis using scanning transmission electronic microscope (STEM). The superimposition of microstructural time-temperature-precipitation (TTP) and ASTM A262 time-temperature-sensitization (TTS) diagrams provides the relationship between aged microstructure and IGC. Moreover, by considering the chromium-depleted zone characteristics, sensitization and desensitization criteria could be established. (2) The electrochemical method involving the double loop-electrochemical potentiokinetic reactivation (DL-EPR) test. The operating conditions of this test were initially optimized using the experimental design method on the bases of the reliability, the selectivity, and the reproducibility of test responses for both annealed and sensitized steels. The TTS diagram of the AISI 316L stainless steel was established using this method. This diagram offers a quantitative assessment of the DOS and a possibility to appreciate the time-temperature equivalence of the IGC sensitization and desensitization. (3) The analytical method based on the chromium diffusion models. Using the IGC sensitization and desensitization criteria established by the microstructural method, numerical solving of the chromium diffusion equations leads to a calculated AISI 316L TTS diagram. Comparison of these three methods gives a clear advantage to the nondestructive DL-EPR test when it is

  10. Measurement and prediction of sensitization development in austenitic stainless steels

    International Nuclear Information System (INIS)

    Bruemmer, S.M.; Charlot, L.A.; Atteridge, D.G.

    1985-10-01

    The effects of thermal and thermomechanical treatments on sensitization development in Type 304 and 316 stainless steels have been measured and compared to model predictions. Sensitization development resulting from isothermal, continuous cooling and pipe welding treatments has been evaluated. An empirically-modified, theoretically-based model is shown to accurately predict material degree of sensitization (DOS) as expressed by the electrochemical potentiokinetic reactivation (EPR) test after both simple and complex treatments. Material DOS is also examined using analytical electron microscopy to document grain boundary chromium depletion and is compared to EPR test results. 9 refs., 13 figs

  11. Nitride alloy layer formation of duplex stainless steel using nitriding process

    Science.gov (United States)

    Maleque, M. A.; Lailatul, P. H.; Fathaen, A. A.; Norinsan, K.; Haider, J.

    2018-01-01

    Duplex stainless steel (DSS) shows a good corrosion resistance as well as the mechanical properties. However, DSS performance decrease as it works under aggressive environment and at high temperature. At the mentioned environment, the DSS become susceptible to wear failure. Surface modification is the favourable technique to widen the application of duplex stainless steel and improve the wear resistance and its hardness properties. Therefore, the main aim of this work is to nitride alloy layer on the surface of duplex stainless steel by the nitriding process temperature of 400°C and 450°C at different time and ammonia composition using a horizontal tube furnace. The scanning electron microscopy and x-ray diffraction analyzer are used to analyse the morphology, composition and the nitrided alloy layer for treated DSS. The micro hardnesss Vickers tester was used to measure hardness on cross-sectional area of nitrided DSS. After nitriding, it was observed that the hardness performance increased until 1100 Hv0.5kgf compared to substrate material of 250 Hv0.5kgf. The thickness layer of nitride alloy also increased from 5μm until 100μm due to diffusion of nitrogen on the surface of DSS. The x-ray diffraction results showed that the nitride layer consists of iron nitride, expanded austenite and chromium nitride. It can be concluded that nitride alloy layer can be produced via nitriding process using tube furnace with significant improvement of microstructural and hardness properties.

  12. Development of a facility for fabricating nuclear waste canisters from radioactively contaminated steel

    International Nuclear Information System (INIS)

    Logan, J.A.; Larsen, M.M.

    1986-01-01

    This paper describes design of a facility and processes capable of using radioactively contaminated waste steel as the principal raw material for fabricating stainless steel canisters to be used for disposal of nuclear high-level waste. By such action, expenditure (i.e., permanent loss to society) of thousands of tons of uncontaminated chromium and nickel to fabricate such canisters can be avoided. Moreover, the cost and risks involved in disposing of large accumulations of radioactively contaminated steel as low-level radioactive waste (LLRW), that would otherwise be necessary, can also be avoided. The canister fabrication processes (involving centrifugal casting) described herein have been tested and proven for this application. The performance characteristics of stainless steel canisters so fabricated have been tested and agreed to by the organizations that have been involved in this development work (Battelle Memorial Institute, DuPont, EGandG and the Savannah River Laboratory) as equivalent to the performance characteristics of canisters fabricated of uncontaminated wrought stainless steel. It is estimated that the production cost for fabricating canisters by the methods described will not differ greatly from the production cost using uncontaminated wrought steel, and the other costs avoided by not having to dispose of the contaminated steel as LLRW could cause this method to produce the lowest ultimate overall costs

  13. The effects of phosphorus and boron on the behavior of a titanium-stabilized austenitic stainless steel developed for fast reactor service

    International Nuclear Information System (INIS)

    Hamilton, M.L.; Johnson, G.D.; Puigh, R.J.; Garner, F.A.; Maziasz, P.J.; Yang, W.J.S.; Abraham, N.

    1988-08-01

    Austenitic stainless steels are used for core component materials in liquid metal cooled reactors (LMRs). To extend the lifetime of LMR fuel assemblies, considerable effort was expended by the US breeder materials program to find ways to minimize radiation-induced dimensional changes (swelling and creep) and to maximize the creep rupture strength. After various elements were shown to strongly affect swelling and creep behavior, compositional modifications to a commercial grade austenitic stainless steel (AISI 316) produced an alloy with significant improvement in swelling resistance over the standard 300 series alloys. Changes were primarily in the concentrations of chromium, nickel, silicon and titanium, ASTM specification A771-83 was approved in 1983 for the new alloy, designated UNS S38660. Substantial improvement can be produced in the creep rupture behavior of this alloy. Elements such as phosphorus and boron, typically present in trace quantities, have a significant influence on the creep strength of austenitic stainless steels. Several heats of alloy S38660 were made that systematically varied the phosphorus and boron contents. Uniaxial creep tests were conducted at 704/degree/C (1300/degree/F) to evaluate the effects of these elements on the creep rate and the rupture life. The results of these tests were used to guide the production of reactor grade fuel pin cladding for further evaluations. Pressurized tube specimens were tested in the laboratory and also in a fast reactor. Results of these investigations have shown that the elements phosphorus and boron, present in minute but controlled amounts, increase both the in- reactor and ex-reactor rupture life and reduce both in-reactor swelling and creep rate. Microstructural evaluations were also conducted to help ascertain the mechanisms by which the improved properties were obtained. 41 refs., 28 figs., 3 tabs

  14. Tensile behavior of borated stainless steels

    International Nuclear Information System (INIS)

    Stephens, J.J. Jr.; Sorenson, K.B.

    1991-01-01

    Borated stainless steel tensile testing is being conducted at Sandia National Laboratories (SNL). The goal of the test program is to provide data to support a code case inquiry to the ASME Boiler and Pressure Vessel Code, Section III. The adoption by ASME facilitates a material's qualification for structural use in transport cask applications. For transport cask basket applications, the potential advantage to using borated stainless steel arises from the fact that the structural and criticality control functions can be combined into one material. This can result in a decrease in net section thickness of the basket web (increased payload capacity) and eliminates the fabrication process and cost of attaching a discrete boron poison material to the basket web. In addition, adding borate stainless steel to the inventory of acceptable structural material provides the Department of Energy (DOE) and its cask contractors an alternative to current proposed materials which have not been qualified for structural service. The test program at SNL involves procuring material, machining test specimens, and conducting the tensile tests. From test measurements obtained so far, general trends indicate that tensile properties (yield strength and ultimate strength) increase with boron content and are in all cases superior to the minimum required properties established in A-240, Type 304, a typical grade of austenitic stainless steel. Therefore, in a designed basket, web thicknesses using borated stainless steel would be comparable to or thinner tan an equivalent basket manufactured from a typical stainless steel without boron additions. General trends from test results indicate that ductilities decrease with increasing boron content

  15. Deformation effects on the development of grain boundary chronium depletion (sensitization) in type 316 austenitic stainless steels

    International Nuclear Information System (INIS)

    Atteridge, D.G.; Wood, W.E.; Advani, A.H.; Bruemmer, S.M.

    1990-01-01

    Deformation induces an acceleration in the kinetics and reduction in the thermodynamic barrier to carbide precipitation and grain boundary chromium depletion (GBCD) development of a high carbon Type 316 stainless steel (SS). This was observed in a study on strain effects on GBCD (or sensitization) development in the range of 575 degree C to 775 degree C. Grain boundary chromium depletion behavior of SS was examined using the indirect electrochemical potentiokinetic reactivation (EPR) test and supported by studies on carbide precipitation using transmission electron microscopy (TEM). 99 refs., 84 figs., 9 tabs

  16. Study of cyclic oxidation for stainless steels AISI 309 T 253 M A, with low additions of cerium; Estudio de la oxidacion ciclica de los aceros inoxidables AISI 309 T 253 MA, con pequenas adiciones de Cerio

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez F, G.L.; Martinez, M.; Ruiz, A. [Universidad Nacional Experimental Politecnica (UNEXPO) - Vicerrectorado de Puerto Ordaz, Centro de Estudios de Corrosion. Puerto Ordaz. venezuela (Venezuela)

    1998-12-31

    It has been detected that the addition of small amounts (<1%) of the so called `reactive elements` such as Cerium to Fe-Cr alloys that was utilized in oxidating environment at high temperatures improving its resistance to oxidation under isothermal and cyclic conditions. In this work, it was evaluated the behavior under cyclic oxidation conditions for an austenitic stainless steel at chromium-nickel (253MA) with cerium addition, and comparing it with the AISI 310S austenitic stainless steel. The cyclic oxidation essays consist of five cycles by 24 hours each one, following of a cooling in air until ambient temperature from the temperatures of 850, 900 and 950 Centigrade, registering the gain mass of the specimen at end of each cycle. In order to this were prepared samples with dimensions of 20 mm. x 10 mm. x 1 mm. Later to the oxidation essays was evaluated the morphology of the corrosion products layer by scanning electron microscopy. The present phases were identified by X-ray diffraction and by chemical microanalysis by Dispersive energy (EDAX). The results obtained show that the steel with cerium addition, presents a higher adherence and resistance to the spalling noting that the cerium promotes the casting anchor of the oxides layer to matrix and by reducing the grain size of the layer improving its plasticity. Additionally the cerium promotes the preferential oxidation of the forming elements of protective layers like the chromium. (Author)

  17. Tritiated Water Interaction with Stainless Steel

    International Nuclear Information System (INIS)

    Glen R. Longhurst

    2007-01-01

    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

  18. Stainless steels: general considerations and rates of crack growth

    International Nuclear Information System (INIS)

    Chator, T.

    1992-05-01

    This report describes the different types of stainless steels, and presents the laws governing the rates of crack growth for several stainless steels extensively used for the manufacture of structures in nuclear power plants. The laws are not discussed in detail in the report. After a brief review of the development of stainless steels, the main categories of stainless steels, their mechanical characteristics and corrosion resistance, are presented. Finally, the rates of crack growth are presented for various stainless steels, mainly austenitic. The study overall aim is an investigation of the cracking in the 900 MWe primary pump thermal barriers and shafts

  19. Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nikel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) seamless pipe and tube

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    Standard specification for Nickel-Chromium-Iron alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696), Nikel-Chromium-Cobalt-Molybdenum alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten alloy (UNS N06674) seamless pipe and tube

  20. Copper and nickel hexacyanoferrate nanostructures with graphene-coated stainless steel sheets for electrochemical supercapacitors

    Science.gov (United States)

    Wu, Mao-Sung; Lyu, Li-Jyun; Syu, Jhih-Hao

    2015-11-01

    Copper and nickel hexacyanoferrate (CuHCF and NiHCF) nanostructures featuring three-dimensional open-framework tunnels are prepared using a solution-based coprecipitation process. CuHCF shows superior supercapacitive behavior than the NiHCF, due to the presence of numerous macropores in CuHCF particles for facilitating the transport of electrolyte. Both CuHCF and NiHCF electrodes with stainless steel (SS) substrate tend to lose their electroactivity towards intercalation/deintercalation of hydrated potassium ions owing to the partial corrosion of SS. Formation of a protective and conductive carbon layer in between SS and CuHCF (NiHCF) film is of paramount importance for improving the irreversible loss of electroactivity. Thin and compact graphene (GN) layer without observable holes in its normal plane is the most effective way to suppress the corrosion of SS compared with porous carbon nanotube and activated carbon layers. Specific capacitance of CuHCF electrode with GN layer (CuHCF/GN/SS) reaches 570 F g-1, which is even better than that of CuHCF with Pt substrate (500 F g-1) at 1 A g-1. The CuHCF/GN/SS exhibits high stability with 96% capacitance retention over 1000 cycles, greater than the CuHCF with Pt (75%).

  1. Low temperature gaseous surface hardening of stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present contribution gives an overview of some of the technological aspects of low temperature thermochemical treatment of stainless steel. Examples of low temperature gaseous nitriding, carburising and nitrocarburising of stainless steel are presented and discussed. In particular......, the morphology, microstructure and characteristics of so-called expanite “layers” on stainless steel are addressed....

  2. Analysis of polypyrrole-coated stainless steel electrodes

    Indian Academy of Sciences (India)

    Analysis of polypyrrole-coated stainless steel electrodes - Estimation of specific ... is carried out on stainless steel electrodes using -toluene sulphonic acid. ... The feasibility of the electrode for supercapacitor applications is investigated.

  3. Tensile-property characterization of thermally aged cast stainless steels

    International Nuclear Information System (INIS)

    Michaud, W.F.; Toben, P.T.; Soppet, W.K.; Chopra, O.K.

    1994-02-01

    The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components

  4. Identification of sigma and chi phases in duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Llorca-Isern, Núria, E-mail: nullorca@ub.edu [Departament de Ciència dels Materials i Enginyeria Metallurgica, Facultat de Química, Universitat de Barcelona, Marti-Franqués 1, 08028 Barcelona (Spain); López-Luque, Héctor, E-mail: hlopezlu7@alumnes.ub.edu [Departament de Ciència dels Materials i Enginyeria Metallurgica, Facultat de Química, Universitat de Barcelona, Marti-Franqués 1, 08028 Barcelona (Spain); López-Jiménez, Isabel, E-mail: ilopezji9@alumnes.ub.edu [Departament de Ciència dels Materials i Enginyeria Metallurgica, Facultat de Química, Universitat de Barcelona, Marti-Franqués 1, 08028 Barcelona (Spain); Biezma, Maria Victoria, E-mail: maria.biezma@unican.es [Department of Earth, Materials Science and Engineering, University of Cantabria - UC, Gamazo, 1, 39004 Santander (Spain)

    2016-02-15

    The aim of this work is to find out the most suitable method for detecting and analyzing accurately the formation conditions of secondary phases, particularly Sigma-phase (σ-phase) and Chi-phase (χ-phase) in duplex stainless steels (UNS S32205 and UNS S32750). The microstructure was characterized after a solution annealing at 1080 °C followed by an isothermal heating at 830 °C for different time ranges, ranging from 1 min to 9 h, in order to enlighten the controversial point concerning the mechanism of χ-phase nucleation in relation with the σ-phase. Etched samples were observed using optical microscopy (MO), and scanning electron microscopy (FESEM) with a backscattered electron detector (BSE) was used on unetched samples. Compositional microanalysis (EDS) was carried out for identifying the different phases present in the steels. Sigma phase was easily observed using different etching procedures, whereas χ-phase was only clearly detected with FESEM–BSE on unetched samples. The compositional analyses showed that the molybdenum content in χ-phase almost doubles the content of this element in σ-phase, and as a result the kinetics of nucleation and growth were also found to be remarkably faster when the alloy content in the steel is higher. In addition, chromium nitrides and carbides were also observed to precipitate as a result of the heat treatments and, in the case of the chromium nitrides, they act as a favorable site for the nucleation of σ-phase and χ-phase. - Highlights: • Microscopy was used on heat treated duplex steels for microstructure identification. • FESEM–BSE observation on unetched samples provided the best contrast between phases. • Analyses of carbides, nitrides, chi and sigma phases were possible by EDS and WDS. • Chromium nitrides act as favorable site for the nucleation of chi and sigma phases. • Secondary phases nucleation kinetics are faster in superduplex than in duplex steels.

  5. Joining silicon carbide to austenitic stainless steel through diffusion welding; Stellingen behorende bij het proefschrift

    Energy Technology Data Exchange (ETDEWEB)

    Krugers, Jan-Paul

    1993-01-19

    In this thesis, the results are presented of a study dealing with joining silicon carbide to austenitic stainless steel AIS316 by means of diffusion welding. Welding experiments were carried out without and with the use of a metallic intermediate, like copper, nickel and copper-nickel alloys at various conditions of process temperature, process time, mechanical pressure and interlayer thickness. Most experiments were carried out in high vacuum. For reasons of comparison, however, some experiments were also carried out in a gas shielded environment of 95 vol.% Ar and 5 vol.% H2.

  6. Bioaccessibility, bioavailability and toxicity of commercially relevant iron- and chromium-based particles: in vitro studies with an inhalation perspective

    Directory of Open Access Journals (Sweden)

    Hedberg Yolanda

    2010-09-01

    Full Text Available Abstract Background Production of ferrochromium alloys (FeCr, master alloys for stainless steel manufacture, involves casting and crushing processes where particles inevitably become airborne and potentially inhaled. The aim of this study was to assess potential health hazards induced by inhalation of different well-characterized iron- and chromium-based particles, i.e. ferrochromium (FeCr, ferrosiliconchromium (FeSiCr, stainless steel (316L, iron (Fe, chromium (Cr, and chromium(IIIoxide (Cr2O3, in different size fractions using in vitro methods. This was done by assessing the extent and speciation of released metals in synthetic biological medium and by analyzing particle reactivity and toxicity towards cultured human lung cells (A549. Results The amount of released metals normalized to the particle surface area increased with decreasing particle size for all alloy particles, whereas the opposite situation was valid for particles of the pure metals. These effects were evident in artificial lysosomal fluid (ALF of pH 4.5 containing complexing agents, but not in neutral or weakly alkaline biological media. Chromium, iron and nickel were released to very low extent from all alloy particles, and from particles of Cr due to the presence of a Cr(III-rich protective surface oxide. Released elements were neither proportional to the bulk nor to the surface composition after the investigated 168 hours of exposure. Due to a surface oxide with less protective properties, significantly more iron was released from pure iron particles compared with the alloys. Cr was predominantly released as Cr(III from all particles investigated and was strongly complexed by organic species of ALF. Cr2O3 particles showed hemolytic activity, but none of the alloy particles did. Fine-sized particles of stainless steel caused however DNA damage, measured with the comet assay after 4 h exposure. None of the particles revealed any significant cytotoxicity in terms of cell death

  7. Chromium, Nickel and Zinc Induced Histopathological Alterations in ...

    African Journals Online (AJOL)

    Michael Horsfall

    fish, Labeo rohita to chlorides of chromium, nickel and zinc for 30 days. However ... toxicants such as salts of heavy metals, acids, organic matter ... nutritional supply becomes excessive. ... action), petrochemicals, and fertilizers and in steam.

  8. Cathodic cage nitriding of AISI 409 ferritic stainless steel with the addition of CH4

    Directory of Open Access Journals (Sweden)

    Rômulo Ribeiro Magalhães de Sousa

    2012-04-01

    Full Text Available AISI 409 ferritic stainless steel samples were nitrided using the cathodic cage plasma nitriding technique (CCPN, with the addition of methane to reduce chromium precipitation, increase hardness and wear resistance and reduce the presence of nitrides when compared to plasma carbonitriding. Microhardness profiles and X-Ray analysis confirm the formation of a very hard layer containing mainly ε-Fe3N and expanded ferrite phases.

  9. Study of the Sensitization on the Grain Boundary in Austenitic Stainless Steel Aisi 316

    Directory of Open Access Journals (Sweden)

    Kocsisová Edina

    2014-12-01

    Full Text Available Intergranular corrosion (IGC is one of the major problems in austenitic stainless steels. This type of corrosion is caused by precipitation of secondary phases on grain boundaries (GB. Precipitation of the secondary phases can lead to formation of chromium depleted zones in the vicinity of grain boundaries. Mount of the sensitization of material is characterized by the degree of sensitization (DOS. Austenitic stainless steel AISI 316 as experimental material had been chosen. The samples for the study of sensitization were solution annealed on 1100 °C for 60 min followed by water quenching and then sensitization by isothermal annealing on 700 °C and 650 °C with holding time from 15 to 600 min. Transmission electron microscopy (TEM was used for identification of secondary phases. Electron backscattered diffraction (EBSD was applied for characterization of grain boundary structure as one of the factors which influences on DOS.

  10. Testing of intergranular and pitting corrosion in sensitized welded joints of austenitic stainless steel

    Directory of Open Access Journals (Sweden)

    Bore V. Jegdic

    2017-06-01

    Full Text Available Pitting corrosion resistance and intergranular corrosion of the austenitic stainless steel X5Cr Ni18-10 were tested on the base metal, heat affected zone and weld metal. Testing of pitting corrosion was performed by the potentiodynamic polarization method, while testing of intergranular corrosion was performed by the method of electrochemical potentiokinetic reactivation with double loop. The base metal was completely resistant to intergranular corrosion, while the heat affected zone showed a slight susceptibility to intergranular corrosion. Indicators of pitting corrosion resistance for the weld metal and the base metal were very similar, but their values are significantly higher than the values for the heat affected zone. This was caused by reduction of the chromium concentration in the grain boundary areas in the heat affected zone, even though the carbon content in the examined stainless steel is low (0.04 wt. % C.

  11. Effect of temperature on corrosion of steels in high purity water

    International Nuclear Information System (INIS)

    Honda, Takashi; Kashimura, Eiji; Ohashi, Kenya; Furutani, Yasumasa; Ohsumi, Katsumi; Aizawa, Motohiro; Matsubayashi, Hideo.

    1987-01-01

    Effect of temperature on corrosion behavior of steels was evaluated in the range of 150 - 300 deg C in high purity water containing about 200 ppb oxygen. The exposure tests were carried out in actual and simulated reactor water of BWR plants. Through X-ray diffractometry, SIMS, XPS and chemical analyses, it was clarified that the chemical composition and morphology of oxide films formed on austenitic stainless steel changed above about 250 deg C. Chromium dissolved easily through corrosion above this temperature, and the oxide films primarily consisted of spinel type oxides containing high concentration of nickel. Further, as the protectivety of oxide films increased with temperature, the corrosion rate had a peak around 250 deg C after a long exposure period. A major phase of oxide films on carbon steel was magnetite in the whole temperature range. However, as the oxide films formed at high temperatures had very compact structures, the effect of temperature on the corrosion rate was similar to that observed on stainless steel. (author)

  12. Influence of Chromium and Molybdenum on the Corrosion of Nickel Based Alloys

    International Nuclear Information System (INIS)

    Hayes, J R; Gray, J; Szmodis, A W; Orme, C A

    2005-01-01

    The addition of chromium and molybdenum to nickel creates alloys with exceptional corrosion resistance in a diverse range of environments. This study examines the complementary roles of Cr and Mo in Ni alloy passivation. Four nickel alloys with varying amounts of chromium and molybdenum were studied in 1 molar salt solutions over a broad pH range. The passive corrosion and breakdown behavior of the alloys suggests that chromium is the primary element influencing general corrosion resistance. The breakdown potential was nearly independent of molybdenum content, while the repassivation potential is strongly dependant on the molybdenum content. This indicates that chromium plays a strong role in maintaining the passivity of the alloy, while molybdenum acts to stabilize the passive film after a localized breakdown event

  13. The influence of lead temperature on the accuracy of various stainless-steel sheathed, mineral-inulated nickel-chromium/nickel aluminium thermocouples

    International Nuclear Information System (INIS)

    Burnett, P.; Burns, J.S.

    1977-10-01

    Samples of three types of stainless steel sheathed MI thermocouples, such as are currently used in fire and furnace tests of transport flasks, have been subjected to high lead temperatures whilst the thermojunctions were kept at a constant low temperature. Both the lead temperature and the length of lead at temperature have been varied. As the lead temperature rises from ambient to a selected value, the emf output from the thermocouple initially decreases and then increases, taking up a final value dependent on the particular conditions. Below a threshold lead temperature, no significant steady state error occurs and the negative transient is generally negligible. Each thermocouple has its own threshold temperature, the lowest found being about 600 0 C, although the average lies at about 750 0 C. Above the threshold lead temperature, the thermal emf can be in error by the equivalent of more than 100 0 C, the highest error found being nearly 230 0 C at a temperature 250 0 C above threshold. The same thermocouple showed a negative transient of 13 0 C 3 minutes after start of heating to 890 0 C. It is probable that the steady state error arises because of the degradation of the thermocouple mineral insulation at elevated temperatures and recommendations are made on the use of such thermocouples in fire and furnace tests. The cause of the initial negative transient error has not been identified, but ways of minimising any resultant errors are suggested. (author)

  14. Experimental exposure of healthy subjects with emissions from a gas metal arc welding process--part II: biomonitoring of chromium and nickel.

    Science.gov (United States)

    Gube, Monika; Brand, Peter; Schettgen, Thomas; Bertram, Jens; Gerards, Kerstin; Reisgen, Uwe; Kraus, Thomas

    2013-01-01

    The objective of this study was to investigate whether there is a relationship between the external exposure dose of chromium and nickel caused by a metal active gas welding process with a solid high-alloyed steel welding wire and inner exposure of subjects. In order to perform welding fume exposure under controlled and standardized conditions, the investigations were conducted in the "Aachen Workplace Simulation Laboratory". To perform biological monitoring of chromium and nickel, blood and urine samples of 12 healthy male non-smokers who never worked as welders were collected before and after a 6-h exposure to ambient air (0 mg/m(3)) and to welding fumes of a metal active gas welding process once with a concentration of the welding fume of 1 mg/m(3) and once with a concentration of 2.5 mg/m(3). Although the internal exposure to chromium and nickel in this study was comparatively low, the subjects showed significantly increased concentrations of these metals in urine after exposure to welding fume compared to the values at baseline. Moreover, the observed increase was significantly dose dependent for both of the substances. For the biological monitoring of chromium and nickel in urine of subjects exposed to welding fumes, a dependency on exposure dose was seen under standardized conditions after a single exposure over a period of 6 h. Thus, this study contributes to a better understanding of the relationship between ambient and biological exposures from welding fumes and provides a good basis for evaluating future biological threshold values for these metals in welding occupation.

  15. Duplex stainless steel surface bay laser cladding

    International Nuclear Information System (INIS)

    Amigo, V.; Pineda, Y.; Segovia, F.; Vicente, A.

    2004-01-01

    Laser cladding is one of the most promising techniques to restore damaged surfaces and achieve properties similar to those of the base metal. In this work, duplex stainless steels have been cladded by a nickel alloy under different processing conditions. The influence of the beam speed and defocusing variables ha been evaluated in the microstructure both of the cladding and heat affected zone, HAZ. These results have been correlated to mechanical properties by means of microhardness measurements from cladding area to base metal through the interface. This technique has shown to be very appropriate to obtain controlled mechanical properties as they are determined by the solidification microstructure, originated by the transfer of mass and heat in the system. (Author) 21 refs

  16. Stainless Steel Round Robin Test: Centrifugally cast stainless steel screening phase

    Energy Technology Data Exchange (ETDEWEB)

    Bates, D J; Doctor, S R; Heasler, P G; Burck, E

    1987-10-01

    This report presents the results of the Centrifugally Cast Stainless Steel Round Robin Test (CCSSRRT). The CCSSRRT is the first phase of an effort to investigate and improve the capability and reliability of NDE inspections of light water reactor piping systems. This phase was a screening test to identify the most promising procedures presently available for CCSS. The next phase will be an in-depth program to evaluate the capability and reliability of inservice inspections (ISI) for piping. In the CCSSRRT, 15 centrifugally cast stainless steel pipe sections containing welds and laboratory-grown thermal fatigue cracks in both columnar and equiaxed base material were used. These pipe specimens were inspected by a total of 18 teams from Europe and the United States using a variety of NDE techniques, mostly ultrasonic (UT). The inspections were carried out at the team's facilities and included inspections from both sides of the weld and inspections restricted to one side of the weld. The results of the CCSSRRT make it apparent that a more detailed study on the capability and reliability of procedures to inspect stainless steel materials is needed to better understand the specific material and flaw properties and how they affect the outcome of an inspection.

  17. Fundamental problems on immiscibility, crystallization, and chemical interaction between stainless steel 304 and glasses for radioactivewaste glasses

    International Nuclear Information System (INIS)

    Inoue, Tadashi; Yokoyama, Hayaichi

    1982-01-01

    Immiscibility and crystallization, and chemical interaction with stainless steel, SUS 304, which is designed as a canister material, were investigated on non-radioactive glasses with simulated waste of 26.4 wt%. Although glasses whose initial color was black changed to yellow or yellow-brown by heat-treatment at 600 0 C, the change of color was hardly observed by the treatment at 850 0 C. Molybdenum oxide and molybdate were detected in all heat-treated glasses. It was deduced that the compounds were existing as meta-stable particle corresponding to immiscibility particle at 600 0 C and as stable crystallized particle at 850 0 C. The chemical interaction occurred at the interface between glasses and SUS 304, whose surface was attacked by boundary corrosion proceeding to uniform corrosion with increasing temperature and time. Chromium oxide layer was mainly formed in the region suffered chemical interaction. It was deduced that the chemical interaction was moderated due to the formation of protective layer, which mainly consisted of nickel oxide, at the same time as the formation of Cr 2 O 3 layer. (author)

  18. A comparative study on microgap of premade abutments and abutments cast in base metal alloys.

    Science.gov (United States)

    Lalithamma, Jaini Jaini; Mallan, Sreekanth Anantha; Murukan, Pazhani Appan; Zarina, Rita

    2014-06-01

    The study compared the marginal accuracy of premade and cast abutments. Premade titanium, stainless steel, and gold abutments formed the control groups. Plastic abutments were cast in nickel-chromium, cobalt-chromium and grade IV titanium. The abutment/implant interface was analyzed. Analysis of variance and Duncan's multiple range test revealed no significant difference in mean marginal microgap between premade gold and titanium abutments and between premade stainless steel and cast titanium abutments. Statistically significant differences (P < .001) were found among all other groups.

  19. SEM and TEM characterization of microstructure of stainless steel composites reinforced with TiB2

    International Nuclear Information System (INIS)

    Sulima, Iwona; Boczkal, Sonia; Jaworska, Lucyna

    2016-01-01

    Steel-8TiB 2 composites were produced by two new sintering techniques, i.e. Spark Plasma Sintering (SPS) and High Pressure-High Temperature (HP-HT) sintering. This study discusses the impact of these sintering methods on the microstructure of steel composites reinforced with TiB 2 particles. Scanning electron microscopy (SEM), wavelength dispersive spectroscopy (WDS), X-ray diffraction, electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used to analyze the microstructure evolution in steel matrix composites. The results of microscopic examinations revealed a close relationship between the composite microstructure and the methods and conditions of sintering. Substantial differences were observed in the grain size of materials sintered by HP-HT and SPS. It has been demonstrated that the composites sintered by HP-HT tend to form a chromium-iron-nickel phase in the steel matrix. In contrast, the microstructure of the composites sintered by SPS is characterized by the presence of complex borides and chromium-iron phase. - Highlights: •The steel-8TiB 2 composites were fabricated by Spark Plasma Sintering (SPS) and High Pressure-High Temperature (HP-HT). •Sintering techniques has an important effect on changes in the microstructure of steel-8TiB 2 composites. •New phases of different size and morphology were identified.

  20. Mechanistic issues for modeling radiation-induced segregation

    International Nuclear Information System (INIS)

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

    1993-03-01

    Model calculations of radiation-induced chromium depletion and radiation-induced nickel enrichment at grain boundaries are compared to measured depletions and enrichments. The model is calibrated to fit chromium depletion in commercial purity 304 stainless steel irradiated in boiling water reactor (BWR) environments. Predicted chromium depletion profiles and the dose dependence of chromium concentration at grain boundaries are in accord with measured trends. Evaluation of chromium and nickel profiles in three neutron, and two ion, irradiation environments reveal significant inconsistencies between measurements and predictions

  1. Improvements to the corrosion resistance of stainless steels for fuel cell applications : supplementary report for phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Kuyucak, S.; Li, J.; Liu, P.; Shehata, M.; Kruszewski, J.; Lo, J.; Guertsman, V.Y.; Gu, G.P. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Materials Technology Laboratory

    2007-07-15

    This paper reported on a newly developed method of making bipolar electrodes from type 304 stainless steel. Two stainless steels were cast, hot-rolled and heat treated. The microstructures were then examined to determine the chromium carbide formation. Plain and mechanically polished samples were sent to General Motors for conductivity measurements to investigate the thermo-mechanical treatment as a means of improving the contact resistance of stainless steel bipolar plates subject to the operating conditions in a proton-exchange membrane (PEM) fuel cell. The treatment induces precipitation of conducive particles. The surface of the stainless steel is etched so that particles protrude from the surface. When the bipolar plates are stacked with sufficient load, the protruding surface precipitates indent into adjacent graphite electrodes, making direct electrical contact. The most common precipitate is M{sub 23}C{sub 6} carbide. This paper described the carbide precipitation required for electrical conductivity and presented a model for electrical conductance across a bipolar plate. It included a description of inter-particle distance and carbide size; carbide formation in type 304 stainless steels; heat-treatment processing of 304 steel for electrical conductance and desensitization; and the effect of steel composition on carbide growth. The experimental work was outlined in terms of casting, hot rolling, cold rolling, heat treatment, aging treatment for carbide growth, and desensitization treatment. Both alloys that were subjected to the thermo-mechanical treatment in this study showed a uniform distribution of carbide precipitates. Their size varied from very small to about 0.8{mu}m. Scanning electron microscopy (SEM) analysis did not detect a change in particle size and population density of these particles with prolonged annealing at 800 degrees C. 4 refs., 6 tabs., 14 figs.

  2. Aortic valve replacement in a patient with severe nickel allergy.

    Science.gov (United States)

    Lusini, Mario; Barbato, Raffaele; Spadaccio, Cristiano; Chello, Massimo

    2011-11-01

    Nickel allergy can raise clinical problems in patients undergoing cardiac surgery who require sternal closure with stainless steel wire. We describe the case of a 51-year-old woman with severe nickel allergy who underwent aortic valve replacement with a nickel-free ON-X prosthesis and sternal closure by Fiberwire # 2 suture without complications. Considering its biocompatibility and its mechanical characteristics including optimal strength and knot resistance, this suture might be a viable alternative in patients in which the use of stainless steel wire is contraindicated. © 2011 Wiley Periodicals, Inc.

  3. High temperature vapor pressures of stainless steel type 1.4970 and of some other pure metals from laser evaporation

    International Nuclear Information System (INIS)

    Bober, M.; Singer, J.

    1984-10-01

    For the safety analysis of nuclear reactors vapor pressure data of stainless steel are required up to temperatures exceeding 4000 K. In analogy to the classic boiling point method a new technique was developed to measure the high-temperature vapor pressures of stainless steel and other metals from laser vaporization. A fast pyrometer, an ion current probe and an image converter camera are used to detect incipient boiling from the time-temperature curve. The saturated-vapor pressure curves of stainless steel (Type 1.4970), being a cladding material of the SNR 300 breeder reactor, and of molybdenum are experimentally determined in the temperature ranges of 2800-3900 K and 4500-5200 K, respectively. The normal boiling points of iron, nickel, titanium, vanadium and zirconium are verified. Besides, spectral emissivity values of the liquid metals are measured at the pyrometer wavelengths of 752 nm and/or 940 nm. (orig.) [de

  4. Stainless steel recycle FY94 progress report

    International Nuclear Information System (INIS)

    Imrich, K.J.

    1994-01-01

    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 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

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

    Science.gov (United States)

    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.

  6. Perspective on present and future alloy development efforts on austenitic stainless steels for fusion application

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1984-01-01

    The purpose of this paper is to address important questions concerning how to effect further alloy development of austenitic stainless steels for resistance, and to what extent the behavior of other properties under irradiation, such as strength/embrittlement, fatigue/irradiation creep, corrosion (under irradiation), and radiation-induced activation must be influenced. To summarize current understanding, helium has been found to have major effects on swelling and embrittlement, but several metallurgical avenues are available for significant improvement relative to type 316 stainless steel. Studies on fatigue and irradiation creep, particularly including helium effects, are preliminary but have yet to reveal engineering problems requiring additional alloy development remedies. The effects of irradiation on corrosion behavior are unknown, but higher alloy nickel contents make thermal corrosion in lithium worse. 67 refs

  7. Ex vivo study on root canal instrumentation of two rotary nickel-titanium systems in comparison to stainless steel hand instruments.

    Science.gov (United States)

    Vaudt, J; Bitter, K; Neumann, K; Kielbassa, A M

    2009-01-01

    To investigate instrumentation time, working safety and the shaping ability of two rotary nickel-titanium (NiTi) systems (Alpha System and ProTaper Universal) in comparison to stainless steel hand instruments. A total of 45 mesial root canals of extracted human mandibular molars were selected. On the basis of the degree of curvature the matched teeth were allocated randomly into three groups of 15 teeth each. In group 1 root canals were prepared to size 30 using a standardized manual preparation technique; in group 2 and 3 rotary NiTi instruments were used following the manufacturers' instructions. Instrumentation time and procedural errors were recorded. With the aid of pre- and postoperative radiographs, apical straightening of the canal curvature was determined. Photographs of the coronal, middle and apical cross-sections of the pre- and postoperative canals were taken, and superimposed using a standard software. Based on these composite images the portion of uninstrumented canal walls was evaluated. Active instrumentation time of the Alpha System was significantly reduced compared with ProTaper Universal and hand instrumentation (P < 0.05; anova). No instrument fractures occurred in any of the groups. The Alpha System revealed significantly less apical straightening compared with the other instruments (P < 0.05; Mann-Whitney U test). In the apical cross-sections Alpha System resulted in significantly less uninstrumented canal walls compared with stainless steel files (P < 0.05; chi-squared test). Despite the demonstrated differences between the systems, an apical straightening effect could not be prevented; areas of uninstrumented root canal wall were left in all regions using the various systems.

  8. Tritium distributing in stainless steel determined by chemical etchin

    International Nuclear Information System (INIS)

    Xiong Yifu; Luo Deli; Chen Changan; Chen Shicun; Jing Wenyong

    2009-01-01

    The depth distribution of tritium in stainless steel was measured by chemical etching. The results show that the method can more quantitatively evaluate the tritium distributing in stainless steel. The maximum amount of tritium which distributed in crystal lattice of stainless steel is limitted by its solubility at room temperature. The other form of tritium in stainless steel is gaseous tritium that are trapped by defects, impurities, fractures, etc. within it. The gaseous tritium is several times more than the solid-dissolved tritium. (authors)

  9. Intergranular aspects of the oxidation of austenitic stainless steels by water vapor at 6000C

    International Nuclear Information System (INIS)

    Hersubeno, J.B. de la S.

    1982-06-01

    This work deals with the corrosion of 17 Cr-13 Ni stainless steel poly- and bicrystals by steam at 600 0 C. For studying the reactions kinetics, several methods were used: discontinuous and continuous (thermobalance) gravimetric techniques, metallography on sections and analysis of the oxides layers (electronic microprobe and radiocrystallography). The main results are the following: - after an ''induction'' period of variable duration, the oxidation kinetics is roughly parabolic. The constants Ksub(p) of the parabolic laws (between 2 and 4x10 -2 μm 2 h -1 for the oxides layers thickness) as well as the induction durations (between 5 and 50 hours) depend on the orientation of crystalline faces exposed to the steam; - oxidation proceeds by formation of an iron, chromium and nickel spinel layer in contact with the alloy and of an external magnetite layer. The spinel layer nearly fills the space left by alloy regression; - the grains boundaries are subject to penetrations or thickness reductions of the spinel layer. This phenomena are strongly related to grains misorientations; for symetrical tilt bicrystals of [001] axis, the boundaries with low (8 0 , 15 0 ) and (67 0 ) misorientations are the most deeply oxidized [fr

  10. Palmtop EPMA by electric battery

    International Nuclear Information System (INIS)

    Imashuku, Susumu; Imanishi, Akira; Kawai, Jun

    2012-01-01

    The measurement pressure of a palmtop electron probe X-ray microanalyzer (EPMA) we previously reported was reduced using stainless steel vacuum flanges for the chamber instead of a borosilicate glass tube. The improved palmtop EPMA could reach the measurement pressure of 1 Pa in 5 minutes. The time was more than twice shorter than that to reach the measurement pressure of 5 Pa with the palmtop EPMA we previously reported. Titanium, copper K lines and silver Lα line were observed during 90 seconds measurement in addition to chromium, iron, and nickel K lines when titanium, copper, and silver plates were placed on the carbon sample stage. Chromium, iron, and nickel K lines came from stainless steel, and copper K lines came from copper rod and copper plate placed on the sample stage. The improved palmtop EPMA can analyze metals except for chromium, iron, nickel, and small amount of copper in 90 seconds.

  11. Structural materialization of stainless steel molds and dies by the low temperature high density plasma nitriding

    Directory of Open Access Journals (Sweden)

    Aizawa Tatsuhiko

    2015-01-01

    Full Text Available Various kinds of stainless steels have been widely utilized as a mold substrate material for injection molding and as a die for mold-stamping and direct stamping processes. Since they suffered from high temperature transients and thermal cycles in practice, they must be surface-treated by dry and wet coatings, or, by plasma nitriding. Martensitic stainless steel mold was first wet plated by the nickel phosphate (NiP, which was unstable at the high temperature stamping condition; and, was easy to crystalize or to fracture by itself. This issue of nuisance significantly lowered the productivity in fabrication of optical elements at present. In the present paper, the stainless steel mold was surface-treated by the low-temperature plasma nitriding. The nitrided layer by this surface modification had higher nitrogen solute content than 4 mass%; the maximum solid-solubility of nitrogen is usually 0.1 mass% in the equilibrium phase diagram. Owing to this solid-solution with high nitrogen concentration, the nitrided layer had high hardness of 1400 Hv within its thickness of 40 μm without any formation of nitrides after 14.4 ks plasma nitriding at 693 K. This nitrogen solid-solution treated stainless steel had thermal resistivity even at the mold-stamping conditions up to 900 K.

  12. Fuel Cell Electrodes Based on Carbon Nanotube/Metallic Nanoparticles Hybrids Formed on Porous Stainless Steel Pellets

    Directory of Open Access Journals (Sweden)

    S. M. Khantimerov

    2013-01-01

    Full Text Available The preparation of carbon nanotube/metallic particle hybrids using pressed porous stainless steel pellets as a substrate is described. The catalytic growth of carbon nanotubes was carried out by CVD on a nickel catalyst obtained by impregnation of pellets with a highly dispersive colloidal solution of nickel acetate tetrahydrate in ethanol. Granular polyethylene was used as the carbon source. Metallic particles were deposited by thermal evaporation of Pt and Ag using pellets with grown carbon nanotubes as a base. The use of such composites as fuel cell electrodes is discussed.

  13. Heat exchanger tubing materials for CANDU nuclear generating stations

    International Nuclear Information System (INIS)

    Taylor, G.F.

    1977-07-01

    The performance of steam generator tubing (nickel-chromium-iron alloy in NPD and nickel-copper alloy in Douglas Point and Pickering generating stations) has been outstanding and no corrosion-induced failures have occurred. The primary coolant will be allowed to boil in the 600 MW (electrical) CANDU-PHW reactors. An iron-nickel-chromium alloy has been selected for the steam generator tubing because it will result in lower radiation fields than the alloys used before. It is also more resistant than nickel-chromium-iron alloy to stress corrosion cracking in the high purity water of the primary circuit, an unlikely but conceivable hazard associated with higher operating temperatures. Austenitic alloy and ferritic-austenitic stainless steel tubing have been selected for the moderator coolers in CANDU reactors being designed and under construction. These materials will reduce the radiation fields around the moderator circuit while retaining the good resistance to corrosion in service water that has characterized the copper-nickel alloys now in use. Brass and bronze tubes in feedwater heaters and condensers have given satisfactory service but do, however, complicate corrosion control in the steam cycle and, to reduce the transport of corrosion products from the feedtrain to the steam generator, stainless steel is preferred for feedwater heaters and stainlss steel or titanium for condensers. (author)

  14. Dietary chromium and nickel enhance UV-carcinogenesis in skin of hairless mice

    International Nuclear Information System (INIS)

    Uddin, Ahmed N.; Burns, Fredric J.; Rossman, Toby G.; Chen, Haobin; Kluz, Thomas; Costa, Max

    2007-01-01

    The skin cancer enhancing effect of chromium (in male mice) and nickel in UVR-irradiated female Skh1 mice was investigated. The dietary vitamin E and selenomethionine were tested for prevention of chromium-enhanced skin carcinogenesis. The mice were exposed to UVR (1.0 kJ/m 2 3x weekly) for 26 weeks either alone, or combined with 2.5 or 5.0 ppm potassium chromate, or with 20, 100 or 500 ppm nickel chloride in drinking water. Vitamin E or selenomethionine was added to the lab chow for 29 weeks beginning 3 weeks before the start of UVR exposure. Both chromium and nickel significantly increased the UVR-induced skin cancer yield in mice. In male Skh1 mice, UVR alone induced 1.9 ± 0.4 cancers/mouse, and 2.5 or 5.0 ppm potassium chromate added to drinking water increased the yields to 5.9 ± 0.8 and 8.6 ± 0.9 cancers/mouse, respectively. In female Skh1 mice, UVR alone induced 1.7 ± 0.4 cancers/mouse, and the addition of 20, 100 or 500 ppm nickel chloride increased the yields to 2.8 ± 0.9, 5.6 ± 0.7 and 4.2 ± 1.0 cancers/mouse, respectively. Neither vitamin E nor selenomethionine reduced the cancer yield enhancement by chromium. These results confirm that chromium and nickel, while not good skin carcinogens per se, are enhancers of UVR-induced skin cancers in Skh1 mice. Data also suggest that the enhancement of UVR-induced skin cancers by chromate may not be oxidatively mediated since the antioxidant vitamin E as well as selenomethionine, found to prevent arsenite-enhanced skin carcinogenesis, failed to suppress enhancement by chromate

  15. Behaviour of carbon steel and chromium steels in CO2 environments

    International Nuclear Information System (INIS)

    Lefebvre, B.; Bounie, P.; Guntz, G.; Prouheze, J.C.; Renault, J.J.

    1984-01-01

    The behavior in aqueous CO 2 environments of steel with chromium content between 0 and 22% has been studied by autoclave tests. The influence of chromium and molybdenum contents has been investigated particularly on 13 Cr steel. Conventional electrochemical test results are related to the CO 2 autoclave test results. The influence of the environment: temperature, chloride concentration, partial pressure of CO 2 and some amount of H 2 S on the corrosion resistance are discussed

  16. Study on tempering behaviour of AISI 410 stainless steel

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  17. Thermal treatments effect on the austenite-ferrite equilibrium in a duplex stainless steel weld beads

    International Nuclear Information System (INIS)

    Belkessa, Brahim; Badji, Riad; Bettahar, Kheireddine; Maza, Halim

    2006-01-01

    Heat treatments in the temperature range between 800 to 1200 C, with a keeping at high temperature of 60 min, followed by a water quenching at 20 C, have been carried out on austeno-ferritic stainless steel welds (of type SAF 2205-UNS S31803). The heat treatments carried out at temperatures below 1000 C have modified the structure of the duplex stainless steel 2205 in inducing the formation of precipitates, identified by X-ray diffraction as being the intermetallic compound σ and the chromium carbides M 23 C 6 . The treatments applied to temperatures superior to 1000 C shift the δ-γ equilibrium towards the δ phase. Indeed, the increase of the ferrite rate with the treatment temperature is approximately linear. The ferrite rates are higher in the heat-affected zone, which has been submitted to a ferritizing due to the welding thermal effects. (O.M.)

  18. The corrosion of austenitic steel in flowing high-temperature water

    International Nuclear Information System (INIS)

    Asmundis, C. de; Weisgerber, P.; Mazzocchi, N.; Plog, C.

    1981-01-01

    This work represents an attempt to obtain data on the corrosion product formation, including corrosion products which are released to the water, of austenitic steel. AISI 316 or DIN Werkstoff No. 14401. The oxidation experiments were carried out in a small laboratory test loop, which was designed for this study. In the stainless water system considered during an oxidation time of 1800 h at 300 0 C, five zones of differing composition developed. 1. The base metal (for comparison) Fe/Cr/Ni = 67/20/13. 2. The metal at the metal/oxide interface nickel enriched, chromium and iron decreased Fe/Cr/Ni = 64/19/17. 3. The inner oxide chromium enriched and iron and nickel decreased Fe/Cr/Ni = 53/32/14. 4. The outer oxide iron enriched, chromium decreased Fe/Cr/Ni = 70/17/13. 5. The corrosion products released to the water, in total, i.e. particulate and dispersed matter, a Fe/Cr/Ni ratio rather close to that base metal: Fe/Cr/Ni = 68/19/13. (80% particulate: Fe/Cr/Ni = 72/23/5, 20% dispersed: Fe/Cr/Ni = 55/1/44)

  19. Sealing of thermally-sprayed stainless steel coatings against corrosion using nickel electroplating technique

    Directory of Open Access Journals (Sweden)

    Hathaipat Koiprasert

    2007-07-01

    Full Text Available Electric arc spraying (EAS is one of the thermal spray techniques used for restoration and to providecorrosion resistance. It can be utilized to build up coatings to thicknesses of several millimeters, It is easy to use on-site. Most importantly, the cost of this technique is lower than other thermal spraying techniques thatmay be suitable for part restoration. A major disadvantage associated with the electric arc sprayed coating is its high porosity, which can be as high as 3-8% making it not appropriate for use in immersion condition. This work was carried out around the idea of using electroplating to seal off the pore of the EAS coating, with an aim to improve the corrosion resistance of the coating in immersion condition. This research compared the corrosion behavior of a stainless steel 316 electric arc sprayed coating in 2M NaOH solution at 25oC. It was found that the Ni plating used as sealant can improve the corrosion resistance of the EAS coating. Furthermore, the smoothened and plated stainless steel 316 coating has a better corrosion resistance than the plated EAS coating that was not ground to smoothen the surface before plating.

  20. Determination of iron, nickel, and chromium in the Masurca simulation rods

    International Nuclear Information System (INIS)

    Brigaudeau, M.; Pierdet, S.

    1969-01-01

    A method has been developed for determining the iron, nickel and chromium content of sintered ternary oxide rods designed to simulate structural elements in the reactor Masurca. During this work a calculation was made of the conditional constant of the Fe-EDTA complex in a formic buffer solution, and of that, of the Ni-EDTA complex in an ammoniacal buffer. From these two values it appears that it is not possible to carry out the iron and nickel determinations with a standard EDTA solution when these two elements are present simultaneously. That is the reason for which, in this case, a separation of the Fe and Ni is carried out in 8 N HCl solution on an anion exchange resin. Each element is then dosed by titricolorimetry. Chromium is determined by the same technique without prior separation. The reproducibility of the method has been calculated for each of the three elements. The relative accuracy is: 0.58 per cent for the iron; 1.41 per cent for the nickel; 0.39 per cent for the chromium. (authors) [fr

  1. Chromium in aqueous nitrate plutonium process streams: Corrosion of 316 stainless steel and chromium speciation

    International Nuclear Information System (INIS)

    Smith, W.H.; Purdy, G.

    1994-01-01

    According to the measurements made in this study, the only situation in which chromium (+6) could exist in a plutonium process solution is one in which a feed containing chromium is dissolved in a glass pot dissolver in high nitric acid concentration and at high temperature. But when the resulting feed is prepared for ion exchange, the chemical treatment reduces chromium to the +3 state. Any solution being processed through the evaporator will only contain chromium in the +3 state and any chromium salts remaining in the evaporator bottoms will be chromium +3 salts

  2. Redemption of asthma pharmaceuticals among stainless steel and mild steel welders

    DEFF Research Database (Denmark)

    Kristiansen, Pernille; Jørgensen, Kristian Tore; Hansen, Johnni

    2015-01-01

    PURPOSE: The purpose was to examine bronchial asthma according to cumulative exposure to fume particulates conferred by stainless steel and mild steel welding through a proxy of redeemed prescribed asthma pharmaceuticals. METHODS: A Danish national company-based historical cohort of 5,303 male ever...... was estimated by combining questionnaire data on welding work with a welding exposure matrix. The estimated exposure accounted for calendar time, welding intermittence, type of steel, welding methods, local exhaustion and welding in confined spaces. Hazard ratios (HRs) with 95 % confidence intervals (CIs) were...... nonsignificant increased rate of redemption of asthma medicine was observed among high-level exposed stainless steel welders in comparison with low-level exposed welders (HR 1.54, 95 % CI 0.76-3.13). This risk increase was driven by an increase risk among non-smoking stainless steel welders (HR 1.46, 95 % CI 1...

  3. Austenitic stainless steel weld inspection

    International Nuclear Information System (INIS)

    Mech, S.J.; Emmons, J.S.; Michaels, T.E.

    1978-01-01

    Analytical techniques applied to ultrasonic waveforms obtained from inspection of austenitic stainless steel welds are described. Experimental results obtained from a variety of geometric and defect reflectors are presented. Specifically, frequency analyses parameters, such as simple moments of the power spectrum, cross-correlation techniques, and adaptive learning network analysis, all represent improvements over conventional time domain analysis of ultrasonic waveforms. Results for each of these methods are presented, and the overall inspection difficulties of austenitic stainless steel welds are discussed

  4. Microchemical evolution of irradiated stainless steels

    International Nuclear Information System (INIS)

    Garner, F.A.

    1980-01-01

    The precipitates that develop during irradiation play the dominant role in the response of 300 series alloys, which alters not only the diffusional properties of point defects but also the rate of acceptance of point defects at dislocations and voids. The major elemental participants are carbon, nickel and silicon. Carbon appears to function as a major governing factor of the route and rate by which the radiation-induced evolution proceeds. It is the sensitivity of carbon's response to a wide range of variables that accounts for much of the variability observed in the swelling of 316 stainless steel. Silicon's role is two-fold: while in solution it depresses void nucleation and determines the duration of the void incubation period, and it also coprecipitates with nickel. The eventual level of nickel in the alloy matrix appears to control the steady-state swelling rate and is determined by the silicon and carbon content. The other participating elements appear to affect primarily the distribution and activity of carbon. Dislocations introduced either by irradiation or cold work likewise appear to influence the role of carbon. Several new physical mechanisms appear to be operating: Inverse Kirkendall effect, interstitial-altered phase stability, solute-interstitial binding, infiltration-exchange process, and creation of radiation-stable precipitates. The sensitivity of the latter phenomenon to temperature and flux has been shown to account for much of the unusual behavior of AISI 316 during irradiation

  5. Microstructural-Scale Model for Surfaces Spreading of Intergranular Corrosion in Sensitized Stainless Steels and Aluminum-Magnesium (AA5XXX) Alloys

    Science.gov (United States)

    Jain, Swati

    Components from AA5XXX (Al-Mg alloys with more than 3 wt% Mg) alloys are X attractive due to availability of low cost, high strength to weight ratio and good weldability. Therefore, these alloys have potential applications in Naval ships. However, these alloys become susceptible to IGC (intergranular corrosion) due to beta-phase precipitation due to improper heat treatment or inadvertent thermal exposure. Stainless steels may also become susceptible due to carbide precipitation and chromium depletion on grain boundaries. IGC susceptibility depends on the interplay between the metallurgical conditions, electrochemical conditions, and chemical conditions. Specific combinations cause IGC while others do not. The objective of this study is to investigate the conditions which bring about surface spreading of IGC in these alloy classes. To accomplish this goal, a microstructure scale model was developed with experimental inputs to understand the 2-D IGC spreading in stainless steels and AA5XXX alloys. The conditions strongly affecting IGC spreading were elucidated. Upon natural and artificial aging, the stainless steels become susceptible to intergranular corrosion because of chromium depletion in the grain boundaries. After aging Al-Mg (AA5XXX) alloys show susceptibility due to the precipitation of the beta-phase (Al3Mg7) in the grain boundaries. Chromium depleted grain boundaries in stainless steels are anodically more active as compared to the interior of the grains. (3-phase rich grain boundaries have lower OCP (open circuit potential) and pitting potentials as compared to the Al-Mg solid solutions. A new approach to modeling the IGC surface spreading in polycrystalline materials that is presented. This model is the first to couple several factors into one granular scale model that illustrates the way in which they interact and IGC occurs. It sheds new information on conditions which cause IGC spreading in two alloy classes and describes a new theory for the critical

  6. Some observations on the carburization of type 316 stainless steel foil in a low carbon activity sodium environment

    International Nuclear Information System (INIS)

    Thorley, A.W.; Jeffcoat, P.J.

    1982-01-01

    Work currently being undertaken to establish the equilibrium composition of carbides which form in stainless steel foils during their exposure to low carbon activity sodium environment is described. The time it takes the carbon to reach equilibrium during exposure to sodium of different carbon activity is discussed. The lowest carbon activity measureable in test loops where the sodium is just above carburizing to stainless steel is reported. Analytical techniques are used to determine the composition of the carbide and the austenite matrix and hence estimate the carbon activity of the equilibrium structure. This provides a comparison with carbon activity values determined by alternative methods such as the Harwell Carbon Meter and nickel tab techniques

  7. Biofouling of Cr-Nickel Spray Coated Films on Steel Surfaces

    International Nuclear Information System (INIS)

    Yoshida, Kento; Kanematsu, Hideyuki; Kuroda, Daisuke; Ikigai, Hajime; Kogo, Takeshi; Yokoyama, Seiji

    2012-01-01

    Nowadays, corrosion of metals brings us serious economic loss and it often reaches several percentage of GNP. Particularly the marine corrosion was serious and the counter measure was very hard to be established, since the number of factors is huge and complicated. One of the complicated factors in marine corrosion is biofouling. Biofouling was classified into two main categories, microfouling and macrofouling. The former is composed of biofilm formation mainly. Marine bacteria are attached to material surfaces, seeking for nutrition in oligotrophic environment and they excrete polysaccharide to form biofilm on metal surfaces. Then larger living matters are attached on the biofilms to develop biofouling on metal surfaces, which often lead loss and failures of metals in marine environments. From the viewpoint of corrosion protection and maintenance of marine structures, biofouling should be mitigated as much as possible. In this study, we applied spray coating to steels and investigated if chromium-nickel spray coating could mitigate the biofouling, being compared with the conventional aluminium-zinc spray coating in marine environments. The specimens used for this investigation are aluminium, zinc, aluminium-zinc, stacked chromium/nickel and those films were formed on carbon steel (JIS SS400). And the pores formed by spray coating were sealed by a commercial reagent for some specimens. All of those specimens were immersed into sea water located at Marina Kawage (854-3, Chisato, Tsu, Mie Prefecture) in Ise Bay for two weeks. The depth of the specimen was two meter from sea water surface and the distance was always kept constant, since they were suspended from the floating pier. The temperature in sea water changed from 10 to 15 degrees Celsius during the immersion test. The biofouling behavior was investigated by low vacuum SEM (Hitachi Miniscope TM1000) and X-ray fluorescent analysis. When the spray coated specimens with and without sealing agents were compared

  8. Electrochemical aspects of stainless steel behaviour in biocorrosive environment

    International Nuclear Information System (INIS)

    Feron, D.

    1990-01-01

    Electrochemical measurements have been used to evaluate and follow, to understand and control microbial induced corrosion of stainless steels. Results include seawater loop tests and laboratory-based microbiological experiments. With natural flowing seawater, impedance spectroscopy measurements have been used to evaluate and follow biofilms on stainless steel tube-electrodes. With batch cultures of single bacterial strain (Sulphate Reducing Bacteria), open-circuit potential measurements and polarization curves performed on 316 L and 430 Ti stainless steels, have shown that the corrosion behaviour of these stainless steels is mainly dependent on the sulphide content of the culture media [fr

  9. Corrosion behavior of sensitized duplex stainless steel.

    Science.gov (United States)

    Torres, F J; Panyayong, W; Rogers, W; Velasquez-Plata, D; Oshida, Y; Moore, B K

    1998-01-01

    The present work investigates the corrosion behavior of 2205 duplex stainless steel in 0.9% NaCl solution after various heat-treatments, and compares it to that of 316L austenitic stainless steel. Both stainless steels were heat-treated at 500, 650, and 800 degrees C in air for 1 h, followed by furnace cooling. Each heat-treated sample was examined for their microstructures and Vickers micro-hardness, and subjected to the X-ray diffraction for the phase identification. Using potentiostatic polarization method, each heat-treated sample was corrosion-tested in 37 degrees C 0.9% NaCl solution to estimate its corrosion rate. It was found that simulated sensitization showed an adverse influence on both steels, indicating that corrosion rates increased by increasing the sensitization temperatures.

  10. Laves intermetallics in stainless steel-zirconium alloys

    International Nuclear Information System (INIS)

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

    1997-01-01

    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) 2+x , have both C36 and C15 crystal structures. A fraction of these intermetallics transform into (Fe,Cr,Ni) 23 Zr 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

  11. Nickel and its alloys as perspective materials for intermediate temperature steam electrolysers operating on proton conducting solid acids as electrolyte

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Jensen, Jens Oluf

    2012-01-01

    Several stainless steels, nickel-based alloys, Ta-coated stainless steel, niobium, nickel, platinum and gold were evaluated as possible materials for use in the intermediate temperature water electrolysers. The corrosion resistance was measured in molten KH2PO4 as simulated conditions corresponding...

  12. Effect of Zr addition on intergranular corrosion of low-chromium ferritic stainless steel

    International Nuclear Information System (INIS)

    Park, Jin Ho; Kim, Jeong Kil; Lee, Bong Ho; Seo, Hyung Suk; Kim, Kyoo Young

    2014-01-01

    Addition of Zr to low-Cr ferritic stainless steel forms a mixture of ZrC and Fe 23 Zr 6 precipitates that can prevent intergranular corrosion. Transmission electron microscopy and three-dimensional atom probe analysis suggest that the ZrC and Fe 23 Zr 6 mixture prevents intergranular corrosion in two ways: by acting as a strong carbide former to suppress the formation of Cr-carbide and by acting as a barrier against the diffusion of the solute Cr towards the grain boundary

  13. Experimental studies on improving the performance of electrochemical machining of high carbon, high chromium die steel using jet patterns

    Directory of Open Access Journals (Sweden)

    V. Sathiyamoorthy

    2014-03-01

    Full Text Available Electrochemical machining (ECM is a non-traditional process used mainly to cut hard or difficult-to-cut metals, where the application of a more traditional process is not convenient. Stiff market competition and ever-growing demand for better, durable and reliable products has brought about a material revolution, which has greatly expanded the families of difficult-to-machine materials namely highcarbon,high-chromium die steel; stainless steel and superalloys. This investigation attempts to analyze the effect of electrolyte distribution on material removal rate (MRR and surface roughness (SR on electrochemical machining of high-carbon, high-chromium die steel using NaCl aqueous solution. Three electrolyte jet patterns namely straight jet in circular, inclined jet in circular and straight jet in spiral were used for this experimentation. The results reveal that electrolyte distribution significantly improves the performance of ECM and the straight jet in spiral pattern performs satisfactorily in obtaining better MRR and surface roughness.

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

    Science.gov (United States)

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

    2017-11-01

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

  15. Radiation-induced sensitisation of stainless steels

    International Nuclear Information System (INIS)

    Norris, D.I.R.

    1987-01-01

    The book contains the proceedings of a symposium on radiation-induced sensitization of stainless steels, which took place at Berkeley, United Kingdom, 1986. The purpose of the symposium was to examine the mechanism leading to inter-granular corrosion of 20%Cr/25% Ni/Nb stainless steel cladding of AGR fuel following irradiation. Nine papers are presented, of which three are theoretical, two papers are based upon corrosion studies of 20%Cr/25%Ni/Nb steel, and the remaining are concerned with compositional redistribution and its measurement. (U.K.)

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

    Science.gov (United States)

    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.

  17. Effect of temperature and pressure on wear properties of ion nitrided AISI 316 and 409 stainless steels

    International Nuclear Information System (INIS)

    Fernandes, Frederico Augusto Pires; Heck, Stenio Cristaldo; Pereira, Ricardo Gomes; Casteletti, Luiz Carlos; Nascente, Pedro Augusto de Paula

    2010-01-01

    Stainless steels are widely used in chemical and other industries due to their corrosion resistance property. However, because of their low hardness and wear properties, their applications are limited. Many attempts have been made to increase the surface hardness of these materials by using plasma techniques. Plasma nitriding is distinguished by its effectiveness, and for presenting a relatively low cost and being a clean process, producing hard surface layers on stainless steels. Aiming to verify the influence of the temperature and pressure on the modified resultant layers, samples of AISI 316 and 409 stainless steels were plasma nitrided in two different temperatures (450 and 500°C) and pressures of 400, 500, and 600Pa for 5h. After the nitriding treatment, the layers were analyzed by means of optical microscopy and wear tests. Wear tests were conducted in a fixed-ball micro-wear machine without lubrication. After the plasma nitriding treatment on AISI 316 and 409 samples, homogeneous and continuous layers were produced and their thicknesses increased as the temperature increased, and as the pressure decreased. The nitriding treatment on the AISI 316 steel sample resulted on the formation of expanded austenite layers at 450°C, and chromium nitrides (CrN and Cr_2N) phases at 500°C. The nitriding treatment on AISI 409 sample yielded the formation of similar layers for both treatment temperatures; these layers constituted mainly by chromium (Cr_2N) and iron (Fe_2N, Fe3_N, and Fe_4N) nitrides. After the nitriding treatment, the AISI 316 steel sample presented higher wear resistance for lower temperature and pressure values. The increase on layer fragility, for higher temperature and pressure values can be responsible for this inverse tendency. The wear resistance of the nitrided AISI 409 sample followed a logic tendency: the harder the layer the better the performance, i.e. the performance was improved with the increase in both the temperature and pressure

  18. Study of the AISI 347 austenitic stainless steel sensitization through the potentiokinetic reactivation method

    International Nuclear Information System (INIS)

    Teodoro, Celso Antonio; Wolynec, Stephan

    1996-01-01

    The sensitization kinetics of AISI 347 austenitic stainless steel samples, removed from a forged bar, was investigated with an electrochemical potentiokinetic reactivation method. After the solution anneal at 1140 deg C, the steel was submitted to sensitization treatments at 550 deg C, 670 deg C, 790 deg C and 910 deg C during times that varied from 1 h to 62 h. It was found that samples treated at 550 deg C, 670 deg C and 790 deg C become sensitized. The activation energy was found to be 124 kJ/mol. The observed behaviour was discussed in terms of both carbon retention in solution after the solution anneal and kinetics of carbon combination with chromium and niobium. (author)

  19. Features of residual stresses in duplex stainless steel butt welds

    Science.gov (United States)

    Um, Tae-Hwan; Lee, Chin-Hyung; Chang, Kyong-Ho; Nguyen Van Do, Vuong

    2018-04-01

    Duplex stainless steel finds increasing use as an alternative to austenitic stainless steel, particularly where chloride or sulphide stress corrosion cracking is of primary concern, due to the excellent combination of strength and corrosion resistance. During welding, duplex stainless steel does not create the same magnitude or distribution of weld-induced residual stresses as those in welded austenitic stainless steel due to the different physical and mechanical properties between them. In this work, an experimental study on the residual stresses in butt-welded duplex stainless steel is performed utilizing the layering technique to investigate the characteristics of residual stresses in the weldment. Three-dimensional thermos-mechanical-metallurgical finite element analysis is also performed to confirm the residual stress measurements.

  20. Chromium Enrichment on P11 Ferritic Steel by Pack Cementation

    Directory of Open Access Journals (Sweden)

    Fauzi F. A.

    2016-01-01

    Full Text Available The future thermal power plant is expected to operate at higher temperature to improve its efficiency and to reduce greenhouse gas emission. This target requires better corrosion properties of ferritic steels, which commonly used as materials for superheater and reheater of boiler tubes. In this work, chromium enrichment on the surface of ferritic steel is studied. The deposited chromium is expected to become a reservoir for the formation of chromia protective layer. Chromium was deposited on the substrate of steel by pack cementation process for two hours at the temperature of 850ºC, 950ºC and 1050ºC, respectively. XRD analysis indicated that chromium was successfully deposited at all temperatures. Somehow, SEM cross sectional image showed that continuous layer of chromium was not continuously formed at 850oC. Therefore, this research clarify that chromium enrichment by pack cementation may be conducted at the temperature above 950°C.

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

    Science.gov (United States)

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

    2016-07-01

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

  2. Microstructure and wear resistance of spray-formed supermartensitic stainless steel

    Directory of Open Access Journals (Sweden)

    Guilherme Zepon

    2013-06-01

    Full Text Available Since the early 90's the oil industry has been encouraging the development of corrosion and wear resistant alloys for onshore and offshore pipeline applications. In this context supermartensitic stainless steel was introduced to replace the more expensive duplex stainless steel for tubing applications. Despite the outstanding corrosion resistance of stainless steels, their wear resistance is of concern. Some authors reported obtaining material processed by spray forming, such as ferritic stainless steel, superduplex stainless steel modified with boron, and iron-based amorphous alloys, which presented high wear resistance while maintaining the corrosion performance1,2. The addition of boron to iron-based alloys promotes the formation of hard boride particles (M2B type which improve their wear resistances3-9. This work aimed to study the microstructure and wear resistance of supermartensitic stainless steel modified with 0.3 wt. (% and 0.7 wt. (% processed by spray forming (SF-SMSS 0.3%B and SF-SMSS 0.7%B, respectively. These boron contents were selected in order to improve the wear resistance of supermartensitic stainless steel through the formation of uniformly distributed borides maintaining the characteristics of the corrosion resistant matrix. SF-SMSS 0.7%B presents an abrasive wear resistance considerably higher than spray-formed supermartensitic stainless steel without boron addition (SF-SMSS.

  3. Effect of nickel and MnS inclusions in the metal on the pitting corrosion of low-carbon stainless steels

    International Nuclear Information System (INIS)

    Frejman, L.I.; Nguen, The Dong; Volkov, D.E.; Konnov, Yu.P.

    1986-01-01

    The resistance to pitting corrosion of steels on the 03Kh17-03Kh18 base containing up to 20 % Ni at different levels of S and Mn impurities contamination is investigated. It is shown that up to 50 % of nickel introduced into ordinary steels with 5-6 % Ni is spent to compensate the resistance decrease caused by MnS inclusions. Full compensation is not attained even in the 10-20 %. Ni range in which nickel practically does not affect the resistance of neither ordinary, nor pure (without MnS) steels. Titanium introduction into ordinary steel on the Kh22N6 base permits to surpass the level of 03Kh17N3 pure steel resistance and attain the level of 03Kh17N6 pure steel almost by all characteristics (including passivated characteristics in sulfuric acid) besides pitting repassivity. In this property pure steels with Ni >or approx. 3 % surpass even the molybdenum containing 03Kh21NbM2T ordinary steel though they by far concede by passivation in sulfuric acid

  4. Effect of the Addition of Nickel Powder and Post Weld Heat Treatment on the Metallurgical and Mechanical Properties of the Welded UNS S32304 Duplex Stainless Steel

    Directory of Open Access Journals (Sweden)

    Ali Tahaei

    Full Text Available Abstract In this research, the effect of the addition of nickel powder and the application of a post weld heat treatment (PWHT on the welding properties of the UNS S32304 lean duplex stainless steel were investigated in order to improve the microstructure and mechanical properties. Nickel powder was directly poured inside the joint gap and mixed with the filler metal during the Gas Tungsten Arc Welding (GTAW process; moreover, the solution heat treatment was performed at 1100 °C for 10 min. The joints were characterized by optical microscopy (OM and the evolution of the phase percentages in the different zones was studied by means of the image analysis technique. Tensile and hardness tests were carried out on the joints in order to evaluate the improvement of the mechanical properties. The results showed that both the addition of nickel powder during the welding process and the post weld heat treatment made it possible to improve the mechanical properties of the weld joints. PWHT had the best effect in restoring the equal percentage of ferrite and austenite compared to the addition of nickel powder.

  5. Special stainless steels for sea water service

    International Nuclear Information System (INIS)

    Tomaselli, A.C.

    1983-01-01

    Very exacting demands are made on the corrosion resistance and mechanical properties of materials which in their service come into contact with seawater, and in many cases simultaneously with corrosive process solutions. The demand for higher alloy stainless steels for seawater application is rising in pace with the increasing requirements for safety and operation economy. The corrosion conditions in seawater and the resistance of stainless steels in this medium will be dealt with in the following. Sanicro 28 will then be compared with stainless steels, types AISI 304, 316 and 317, as well as with Alloy 20, Alloy 825 and SANDVIK 2RK65. (Author) [pt

  6. Study on the hydrogen embrittlement and corrosion of stainless steels used as NI/MHX battery containers

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, H.J.; Chan, S.L.I. [National Taiwan University, Taipei (China); Chen, S.Y. [Chung Shan Institute of Science and Technology, Lung-Tan (China)

    1998-07-01

    Stainless steels are used as the containers for Nickel-metal hydride (Ni/MHx) batteries. In this work stainless steel 304, 304L, 316, 316L, 17-4PH and 430 were selected to study their relative susceptibility to hydrogen embrittlement and alkaline corrosion under battery environments. Comparisons were made by immersion test under different hydrogen pressure over the electrolyte, U-bend tests and slow strain rate tensile test with cathodic H{sub 2} charging. The results showed that high strength 17-4PH suffered severe corrosion after long time immersion in the electrolyte solution and were sensitive to hydrogen embrittlement after hydrogen charging. Ferritic 430 performed better than 17-4PH during immersion test but lost its ductility after hydrogen charging. All the austenitic steels (304, 304L, 316, 316L) were found to be suitable as the materials for Ni/MHx battery container, and the present tests can not discriminate their relative resistance to the corrosion and hydrogen embrittlement in the electrolyte. 5 refs.

  7. The nitriding of solution treated A1S1 type 316 stainless steel in ammonia-hydrogen mixtures

    International Nuclear Information System (INIS)

    Tyfield, S.P.; Mackway, J.

    1975-08-01

    A study is described of the nitriding of 316 stainless steel in NH 3 /H 2 mixtures between 500 0 C and 800 0 C to examine the application of the rate data, so obtained, to nitriding in molecular nitrogen. The rate of nitriding in NH 3 -H 2 was found to be parabolic, at nitrogen potentials insufficient to produce surface iron nitrodes. The rate determining process is interpreted to be dependent on both chromium nitride precipitation and nitrogen diffusion. It is concluded that the kinetics of nitriding 316 stainless steel in molecular nitrogen between 500 0 C and 800 0 C are not reliably predicted on the basis of accelerated kinetic results produced either by increasing the nitrogen potential by the use of NH 3 /H 2 mixtures or by elevating the temperature as reported elsewhere. (U.K.)

  8. Comparison of chromium and nickel uptake of plants grown in different soils

    Energy Technology Data Exchange (ETDEWEB)

    Vago, I. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary); Gyoeri, Z. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary); Loch, J. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary)

    1996-03-01

    The chromium and nickel uptake of ryegrass has been examined in pot experiments in extremely different soils, poor sandy and fertile black chernozem. The effect of calcium carbonate doses and nitrogen supply on heavy metal uptake of the plant has been studied for chromium and nickel loadings (0-100 mg/kg Cr{sup 3+} or Ni{sup 2+}) applied as inorganic salts. The ability to uptake Cr{sup 3+} and Ni{sup 2+} differs significantly and is highly affected by the characteristics of soils, and depends on the metal investigated. The heavy metal uptake of the plant differs significantly in acid, colloid deficient sandy soils; while artificial chromium contamination did not modify the dry-matter production in the pots in either soil, a large quantity of nickel reduced the yields significantly. Nitrogen application did not change significantly the uptake of heavy metals. Lime application reduced the Ni{sup 2+} uptake of plants considerably, especially in sandy soil. In case of a calcium carbonate addition the dry-matter production of the plant was not affected by nickel. In chernozem soil the effect of lime application - i.e., the reduction of nickel uptake - was of a lesser degree. The significantly lesser Cr{sup 3+} uptake was further limited by a calcium carbonate application for both soils studied. A graphic presentation of these effects is given. (orig.). With 3 figs., 3 tabs.

  9. Soft-martensitic stainless Cr-Ni-Mo steel for turbine rotors in geothermic power stations

    International Nuclear Information System (INIS)

    Schonfeld, K.; Potthast, E.

    1986-01-01

    Steel Grade X5 Cr-Ni-Mo 12 6 containing 0.05% carbon, 12% chromium, 6% nickel, and 1.50% molybdenum is an advantageous material for turbine rotors in geothermic power stations because of its excellent strength and toughness properties in combination with good erosion and corrosion resistance. In terms of the phase diagram, this soft-martensitic steel has its place at the martensite/austenite/ferrite interface. Therefore, its chemical composition must be chosen so as to have a completely martensitic structure after hardening. The manufacture of and the mechanical properties of a turbine rotor 1200 mm in diameter by 5600 mm in length with a finished weight of approximately 21.5 tons are described in detail

  10. Fatigue life evaluation method of austenitic stainless steel in PWR water

    International Nuclear Information System (INIS)

    Sakaguchi, Katsumi; Nomura, Yuichiro; Suzuki, Shigeki; Kanasaki, Hiroshi; Higuchi, Makoto

    2006-09-01

    It is known that the fatigue life in elevated temperature water is substantially reduced compared with that in the air. The fatigue life reduction has been investigated experimentally in EFT project of Japan Nuclear Energy Safety Organization (JNES) to evaluate the environmental effect on fatigue life. Many tests have been done for carbon, low alloy, stainless steels and nickel-based alloy under the various conditions. In this paper, the results of the stainless steel in simulated PWR water environments were reported. Fatigue life tests in simulated PWR environments were carried out and the effect of key parameters on fatigue life reduction was examined. The materials used in this study were base and weld metal of austenitic stainless steel SS316, weld metal of SS304 and the base and aged metal of the duplex stainless steel SCS14A. In order to evaluate the effects of stain amplitude, strain rate, strain ratio, temperature, aging, water flow rate and strain holding time, many fatigue tests were examined. In transient condition in an actual plant, however, such parameters as temperature and strain rate are not constant. In order to evaluate fatigue damage in actual plant on the basis of experimental results under constant temperature and strain rate condition, the modified rate approach method was developed. Various kinds of transient have to be taken into account of in actual plant fatigue evaluation, and stress cycle of several ranges of amplitude has to be considered in assessing damage from fatigue. Generally, cumulative usage factor is applied in this type of evaluation. In this study, in order to confirm the applicability of modified rate approach method together with cumulative usage factor, fatigue tests were carried out by combining stress cycle blocks of different strain amplitude levels, in which strain rate changes in response to temperature in a simulated PWR water environment. Consequently, fatigue life could be evaluated with an accuracy of factor of 3

  11. Pitting and stress corrosion cracking of stainless steel

    Science.gov (United States)

    Saithala, Janardhan R.

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

  12. Substitution of modified 9 Cr-1 Mo steel for austentic stainless steels

    International Nuclear Information System (INIS)

    Sikka, V.K.

    1982-04-01

    This report describes the current program to develop a high-strength ferritic-martensitic steel. The alloy is essentially Fe-9% Cr-1% Mo with small additions of V and Nb and is known as modifed 9 Cr-1 Mo steel. Its elevated-temperature properties and design allowable stresses match those of type 304 stainless steel for temperatures up to 600 0 C and exceed those of other ferritic steels by factors of 2 to 3. The improved strength of this alloy permits its use in place of stainless steels for many applications

  13. Self-protective powder wire for semiautomatic welding of corrosion resistant chromium-nickel type 18-10 steels

    International Nuclear Information System (INIS)

    Lipodaev, V.N.; Kakhovskij, N.I.; Fadeeva, G.V.

    1977-01-01

    Self-protecting NP-ANV1 powder wire has been developed for welding 18-10 type stainless steels. The use of the wire provides for the same running properties of the welds as the TsL-11 electrodes, the welding being 3-5 times more efficient

  14. Fusion welding of borated stainless steels

    International Nuclear Information System (INIS)

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

    1993-01-01

    Borated austenitic stainless steels have been developed for use in the nuclear industry where storage, transport, and reprocessing of nuclear materials are required. The objective of this work is to develop appropriate joining technology for borated stainless steels based upon understanding the response of these materials to thermal processing involving melting. This understanding is being developed through the application of physical metallurgy techniques to determine the evolution of microstructure and mechanical properties within the various regions of the HAZ. Initial investigations include development of the kinetics of boride coarsening in the solid-state region of HAZ and the effect of boride coarsening on the impact properties of this region of the weld zone. Microstructures of the borated stainless steels, their response to high temperature isothermal heat treatments, and the implications of these heat treatments with respect to welding behavior will be presented

  15. HIP bonding between niobium/copper/stainless steel materials

    International Nuclear Information System (INIS)

    Inoue, Hitoshi; Fujino, Takeo; Hitomi, Nobuteru; Saito, Kenji; Yamada, Masahiro; Shibuya, Junichi; Ota, Tomoko

    2000-01-01

    We have used niobium flanges for the niobium bulk superconducting RF cavities, however, they are expensive. Stainless steel flanges instead of the niobium flanges will be used in the future large scale production of sc cavities like the KEK/JAERI joint project. For a future R and D of the vacuum sealing related to the clean horizontal assembly method or development of cavities welded a helium vessel in the KEK/JAERI joint project, a converter section of niobium material to stainless steel is required. From these requirements we need to develop the converter. We have tried a HIP bonding method between niobium materials and stainless steel or copper material. It was made clear that the technology could offer an enough bonding strength even higher than niobium tensile strength in the joined surface between niobium and stainless steel or copper. (author)

  16. Modeling of Ni Diffusion Induced Austenite Formation in Ferritic Stainless Steel Interconnects

    DEFF Research Database (Denmark)

    Chen, Ming; Alimadadi, Hossein; Molin, Sebastian

    2017-01-01

    Ferritic stainless steel interconnect plates are widely used in planar solid oxide fuel cell and electrolysis cell stacks. During stack production and operation, nickel from the Ni/yttria stabilized zirconia fuel electrode or from the Ni contact component layer diffuses into the interconnect plate......, causing transformation of the ferritic phase into an austenitic phase in the interface region. This is accompanied with changes in volume, and in mechanical and corrosion properties of the interconnect plates. In this work, kinetic modeling of the inter-diffusion between Ni and FeCr based ferritic...

  17. Properties of high temperature low cycle fatigue in austenitic stainless steel

    International Nuclear Information System (INIS)

    Kim, D. H.; Han, C. H.; Ryu, W. S.

    2002-01-01

    Tensile and fatigue tests were conducted at R. T. and 300 .deg. C for type 304 and 316 stainless steel. Tensile strength and elongation decreased and fatigue life increased with temperature for both type 304 and 316 stainless steel. Dislocation structures were mixed with cell and planar at R. T. and 300 .deg. C for both type 304 and 316 stainless steel. Strain induced martensite of type 316 stainless steel was less than that of type 304 stainless steel and decreased with temperature. It is considered that strain induced martensite is an important factor to increase fatigue life at 300 .deg. C

  18. Low-temperature creep of austenitic stainless steels

    Science.gov (United States)

    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.

  19. Effect of preparative treatment on the corrosion resistance of duplex stainless steel

    International Nuclear Information System (INIS)

    Rieder, E.S.; Eagleton, T.S.; Farr, J.P.G.; Li, X.; Strangwood, M.; Ashworth, M.A.

    1999-01-01

    The effect of surface treatment on the characteristics of the passive film on a super duplex stainless steel is addressed. Auger Electron Spectroscopy (AES) has been used to provide in-depth chemical profile analyses of the passivation film. This study showed that the constitution of the film is largely dependent on the electrolytic conditions under which it is produced or to which it is submitted. The passive films formed by polarisation in an alkaline solution (boric-borate solution) consist of two regions, an inner region rich in chromium and an outer region rich in iron, whilst the films produced in acid solution only present the chromium - rich region. The film thickness is also greatly affected by the polarisation conditions. It can vary from ca. 8 monolayers to about 20 monolayers for cathodically and anodically polarised specimens respectively. The microstructure of weldmetal is also discussed. (author)

  20. Stress corrosion cracking of nickel base alloys in PWR primary water

    International Nuclear Information System (INIS)

    Guerre, C.; Chaumun, E.; Crepin, J.; De Curieres, I.; Duhamel, C.; Heripre, E.; Herms, E.; Laghoutaris, P.; Molins, R.; Sennour, M.; Vaillant, F.

    2013-01-01

    Stress corrosion cracking (SCC) of nickel base alloys and associated weld metals in primary water is one of the major concerns for pressurized water reactors (PWR). Since the 90's, highly cold-worked stainless steels (non-sensitized) were also found to be susceptible to SCC in PWR primary water ([1], [2], [3]). In the context of the life extension of pressurized water reactors, laboratory studies are performed in order to evaluate the SCC behaviour of components made of nickel base alloys and of stainless steels. Some examples of these laboratory studies performed at CEA will be given in the talk. This presentation deals with both initiation and propagation of stress corrosion cracks. The aims of these studies is, on one hand, to obtain more data regarding initiation time or crack growth rate and, one the other hand, to improve our knowledge of the SCC mechanisms. The aim of these approaches is to model SCC and to predict components life duration. Crack growth rate (CGR) tests on Alloy 82 with and without post weld heat treatment are performed in PWR primary water (Figure 1). The heat treatment seems to be highly beneficial by decreasing the CGR. This result could be explained by the effect of thermal treatment on the grain boundary nano-scopic precipitation in Alloy 82 [4]. The susceptibility to SCC of cold worked austenitic stainless steels is also studied. It is shown that for a given cold-working procedure, SCC susceptibility increases with increasing cold-work ([2], [5]). Despite the fact that the SCC behaviour of Alloy 600 has been widely studied for many years, recent laboratory experiments and analysis ([6], [7], [8]) showed that oxygen diffusion is not a rate-limiting step in the SCC mechanism and that chromium diffusion in the bulk close the crack tip could be a key parameter. (authors)

  1. NEW SERDP Project: Copper- Beryllium Alternatives Alloys Development

    Science.gov (United States)

    2011-02-10

    Nitronic60, HBN 304 stainless steel , as well as low friction coating\\liner systems on PH stainless steel substrates • Compression strength and...ChemistryRefining Lath Martensite : Ms≥200°C Nickel: Cleavage Resistance Cobalt: SRO Recovery Resistance Chromium: Corrosion Resistance σuts > 280 ksi σys...against representative steels ). o Compression testing from each of the Cu- and Co-based alloys will be performed per ASTM E 9 o Pin-on-Disk test per

  2. 77 FR 32998 - Tin- and Chromium-Coated Steel Sheet From Japan

    Science.gov (United States)

    2012-06-04

    ...-Coated Steel Sheet From Japan Determination On the basis of the record \\1\\ developed in the subject five... order on tin- and chromium-coated steel sheet from Japan would be likely to lead to continuation or... USITC Publication 4325 (May 2012), entitled Tin- and Chromium-Coated Steel Sheet from Japan...

  3. Observations of a fcc helium gas-bubble superlattice in copper, nickel, and stainless steel

    International Nuclear Information System (INIS)

    Johnson, P.B.; Mazey, D.J.

    1980-01-01

    Transmission electron microscopy is used to investigate the spatial arrangement of the small gas bubbles produced in several fcc metals by 30 keV helium ion irradiation to high dose at 300 K. In what is a new result for this important class of metals it is found that the helium gas bubbles lie on a superlattice having an fcc structure with principal axes aligned with those of the metal matrix. The bubble lattice constant asub(i), is measured for a helium fluence just below the critical dose for radiation blistering of the metal surface (approximately 4 x 10 17 He/cm 2 ). Implantation rates are typically approximately 10 14 He ions cm -2 sec -1 . The values of asub(i) obtained for copper, nickel and stainless steel are (7.6 +- 0.3)nm, (6.6 +- 0.5)nm and (6.4 +- 0.5)nm respectively. Above the critical dose the bubble lattice is seen to survive in some blister caps as well as in the region between blisters. Bubble alignment is also observed in the case of hydrogen bubbles produced in copper by low energy proton irradiation to high fluence at 300 K. The presentation of this data was accompanied by a cine film illustrating the behaviour of the gas bubble lattice in copper during post-irradiation annealing in the electron microscope. A summary of the film is given in the appendix. (author)

  4. Effect of Silicon on Intergranular Corrosion Resistance of Ti-stabilized 11 wt% Cr Ferritic Stainless Steels

    International Nuclear Information System (INIS)

    Hyun, Youngmin; Kim, Heesan

    2013-01-01

    Ti-stabilized 11 wt% Cr ferritic stainless steels (FSSs) for automotive exhaust systems have been experienced intergranular corrosion (IC) in some heat-affected zone (HAZ). The effects of sensitizing heat-treatment and silicon on IC were studied. Time-Temperature-Sensitization (TTS) curves showed that sensitization to IC was observed at the steels heat-treated at the temperature lower than 650 .deg. C and that silicon improved IC resistance. The sensitization was explained by chromium depletion theory, where chromium is depleted by precipitation of chromium carbide during sensitizing heat-treatment. It was confirmed with the results from the analysis of precipitates as well as the thermodynamical prediction of stable phases. In addition, the role of silicon on IC was explained with the stabilization of grain boundary. In other words, silicon promoted the formation of the grain boundaries with low energy where precipitation was suppressed and consequently, the formation of Cr-depleted zone was retarded. The effect of silicon on the formation of grain boundaries with low energy was proved by the analysis of coincidence site lattice (CSL) grain boundary, which is a typical grain boundary with low energy

  5. Effect of Silicon on Intergranular Corrosion Resistance of Ti-stabilized 11 wt% Cr Ferritic Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Youngmin; Kim, Heesan [Hongik Univ., Sejong (Korea, Republic of)

    2013-06-15

    Ti-stabilized 11 wt% Cr ferritic stainless steels (FSSs) for automotive exhaust systems have been experienced intergranular corrosion (IC) in some heat-affected zone (HAZ). The effects of sensitizing heat-treatment and silicon on IC were studied. Time-Temperature-Sensitization (TTS) curves showed that sensitization to IC was observed at the steels heat-treated at the temperature lower than 650 .deg. C and that silicon improved IC resistance. The sensitization was explained by chromium depletion theory, where chromium is depleted by precipitation of chromium carbide during sensitizing heat-treatment. It was confirmed with the results from the analysis of precipitates as well as the thermodynamical prediction of stable phases. In addition, the role of silicon on IC was explained with the stabilization of grain boundary. In other words, silicon promoted the formation of the grain boundaries with low energy where precipitation was suppressed and consequently, the formation of Cr-depleted zone was retarded. The effect of silicon on the formation of grain boundaries with low energy was proved by the analysis of coincidence site lattice (CSL) grain boundary, which is a typical grain boundary with low energy.

  6. Cavitation erosion of chromium-manganese and chromium-cobalt coatings processed by laser beam

    International Nuclear Information System (INIS)

    Giren, B.G.; Szkodo, M.

    2002-01-01

    In this work the cavitation erosion of chromium-manganese and chromium-cobalt clads were tested, each of them for three cases: (1) without additional processing; (2) after laser heating of the solid state and (3) after laser remelting of the material. Armco iron, carbon steel 45 and chromium-nickel steel 0H18N9T were used as substrates. C.W. CO 2 laser with a beam power of 1000 W was used as a source of radiation. The investigated samples were subjected to cavitation impingement in a rotating disk facility. The results indicate that laser processing of the thick, electrode deposited coatings by laser beam leads in some cases to an increase of their cavitation resistance. Strong dependence of the coatings performance on the substrate, both for the laser processed or unprocessed parts of the materials was also discovered. (author)

  7. Arc brazing of austenitic stainless steel to similar and dissimilar metals

    Science.gov (United States)

    Moschini, Jamie Ian

    There is a desire within both the stainless steel and automotive industries to introduce stainless steel into safety critical areas such as the crumple zone of modem cars as a replacement for low carbon mild steel. The two main reasons for this are stainless steel's corrosion resistance and its higher strength compared with mild steel. It has been anticipated that the easiest way to introduce stainless steel into the automotive industry would be to incorporate it into the existing design. The main obstacle to be overcome before this can take place is therefore how to join the stainless steel to the rest of the car body. In recent times arc brazil g has been suggested as a joining technique which will eliminate many of the problems associated with fusion welding of zinc coated mild steel to stainless steel.Similar and dissimilar parent material arc brazed joints were manufactured using three copper based filler materials and three shielding gases. The joints were tested in terms of tensile strength, impact toughness and fatigue properties. It was found that similar parent material stainless steel joints could be produced with a 0.2% proof stress in excess of the parent material and associated problems such as Liquid Metal Embrittlement were not experienced. Dissimilar parent material joints were manufactured with an ultimate tensile strength in excess of that of mild steel although during fatigue testing evidence of Liquid Metal Embrittlement was seen lowering the mean fatigue load.At the interface of the braze and stainless steel in the similar material butt joints manufactured using short circuit transfer, copper appeared to penetrate the grain boundaries of the stainless steel without embrittling the parent material. Further microscopic investigation of the interface showed that the penetration could be described by the model proposed by Mullins. However, when dissimilar metal butt joints were manufactured using spray arc transfer, penetration of copper into the

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

    Directory of Open Access Journals (Sweden)

    Bibo Yao

    2016-03-01

    Full Text Available 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.

  9. Electrochemical reduction of nickel ions from dilute solutions

    NARCIS (Netherlands)

    Njau, K.N.; Janssen, L.J.J.

    1995-01-01

    Electrochemical reduction of nickel ions in dilute solution using a divided GBC-cell is of interest for purification of waste waters. A typical solution to be treated is the effluent from steel etching processes which contain low quantities of nickel, chromate and chromium ions. Reduction of

  10. Martensitic transformation in an intergranular corrosion area of austenitic stainless steel during thermal cycling

    International Nuclear Information System (INIS)

    La Fontaine, Alexandre; Yen, Hung-Wei; Trimby, Patrick; Moody, Steven; Miller, Sarah; Chensee, Martin; Ringer, Simon; Cairney, Julie

    2014-01-01

    An oxidation-assisted martensitic phase transformation was observed in an austenitic stainless steel after thermal cycling up to 970 °C in air in a solar thermal steam reformer. The intergranular corrosion areas were investigated by electron backscatter diffraction (EBSD), transmission Kikuchi diffraction (TKD) and transmission electron microscopy (TEM). The structural-and-chemical maps revealed that within intergranular corrosion areas this martensitic transformation primarily occurs in oxidation-induced chromium-depleted zones, rather than due to only sensitization. This displacive transformation may also play a significant role in the rate at which intergranular corrosion takes place

  11. Measurement and prediction of thermochemical history effects on sensitization development in austenitic stainless steels

    International Nuclear Information System (INIS)

    Bruemmer, S.M.; Charlot, L.A.

    1985-11-01

    The effects of thermal and thermomechanical treatments on sensitization development in Type 304 and 316 stainless steels have been measured and compared to model predictions. Sensitization development resulting from isothermal, continuous cooling and pipe welding treatments has been evaluated. An empirically modified, theoretically based model is shown to accurately predict material degree of sensitization (DOS) as expressed by the electrochemical potentiokinetic reactivation (EPR) test after both simple and complex treatments. Material DOS is also examined using analytical electron microscopy to document grain boundary chromium depletion and is compared to EPR test results

  12. Precipitation hardening in a 12%Cr-9%Ni-4%Mo-2%Cu stainless steel

    International Nuclear Information System (INIS)

    Haettestrand, Mats; Nilsson, Jan-Olof; Stiller, Krystyna; Liu Ping; Andersson, Marcus

    2004-01-01

    A combination of complementary techniques including one-dimensional and three-dimensional atom probe, energy-filtered transmission electron microscopy and conventional transmission electron microscopy has been used to assess the precipitation reactions at 475 deg. C in a 12%Cr-9%Ni-4%Mo-2%Cu precipitation hardening stainless steel. The continuous hardening up to at least 1000 h of ageing was attributed to a sequence of precipitation reactions involving nickel-rich precipitates nucleating at copper clusters followed by molybdenum-rich quasicrystalline precipitates and nickel-rich precipitates of type L1 0 . An estimate of the relative contributions to the strength increment during tempering based on measurements of particle densities was performed. Nickel-rich precipitates were found to play the most important role up to about 40 h of ageing after which the effect of quasicrystalline particles became increasingly important

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

    Directory of Open Access Journals (Sweden)

    Wenning Shen

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

  14. Low temperature plasma carburizing of AISI 316L austenitic stainless steel and AISI F51 duplex stainless steel

    OpenAIRE

    Pinedo,Carlos Eduardo; Tschiptschin,André Paulo

    2013-01-01

    In this work an austenitic AISI 316L and a duplex AISI F51 (EN 1.4462) stainless steel were DC-Plasma carburized at 480ºC, using CH4 as carbon carrier gas. For the austenitic AISI 316L stainless steel, low temperature plasma carburizing induced a strong carbon supersaturation in the austenitic lattice and the formation of carbon expanded austenite (γC) without any precipitation of carbides. The hardness of the carburized AISI 316L steel reached a maximum of 1000 HV due to ∼13 at% c...

  15. Low temperature plasma carburizing of AISI 316L austenitic stainless steel and AISI F51 duplex stainless steel

    OpenAIRE

    Pinedo, Carlos Eduardo; Tschiptschin, André Paulo

    2013-01-01

    In this work an austenitic AISI 316L and a duplex AISI F51 (EN 1.4462) stainless steel were DC-Plasma carburized at 480ºC, using CH4 as carbon carrier gas. For the austenitic AISI 316L stainless steel, low temperature plasma carburizing induced a strong carbon supersaturation in the austenitic lattice and the formation of carbon expanded austenite (γC) without any precipitation of carbides. The hardness of the carburized AISI 316L steel reached a maximum of 1000 HV due to ∼13 at% carbon super...

  16. Evaluation by the Double Loop Electrochemical Potentiokinetic Reactivation Test of Aged Ferritic Stainless Steel Intergranular Corrosion Susceptibility

    Science.gov (United States)

    Sidhom, H.; Amadou, T.; Braham, C.

    2010-12-01

    An experimental design method was used to determine the effect of factors that significantly affect the response of the double loop-electrochemical potentiokinetic reactivation (DL-EPR) test in controlling the susceptibility to intergranular corrosion (IGC) of UNS S43000 (AISI 430) ferritic stainless steel. The test response is expressed in terms of the reactivation/activation current ratio ( I r / I a pct). Test results analysed by the analysis of variance (ANOVA) method show that the molarity of the H2SO4 electrolyte and the potential scanning rate have a more significant effect on the DL-EPR test response than the temperature and the depassivator agent concentration. On the basis of these results, a study was conducted in order to determine the optimal operating conditions of the test as a nondestructive technique for evaluating IGC resistance of ferritic stainless steel components. Three different heat treatments are considered in this study: solution annealing (nonsensitized), aging during 3 hours at 773 K (500 °C) (slightly sensitized), and aging during 2 hours at 873 K (600 °C) (highly sensitized). The aim is to find the operating conditions that simultaneously ensure the selectivity of the attack (intergranular and chromium depleted zone) and are able to detect the effect of low dechromization. It is found that a potential scanning rate of 2.5 mV/s in an electrolyte composed of H2SO4 3 M solution without depassivator, at a temperature around 293 K (20 °C), is the optimal operating condition for the DL-EPR test. Using this condition, it is possible to assess the degree of sensitization (DOS) to the IGC of products manufactured in ferritic stainless steels rapidly, reliably, and quantitatively. A time-temperature-start of sensitization (TTS) diagram for the UNS S43000 (France Inox, Villepinte, France) stainless steel was obtained with acceptable accuracy by this method when the IGC sensitization criterion was set to I r / I a > 1 pct. This diagram is in

  17. IASCC susceptibility and IT'S improvement of austenitic stainless steels for core internals of PWR

    International Nuclear Information System (INIS)

    Yonezawa, T.; Arioka, K.; Kanasaki, S.; Fujimoto, K.; Otsuka, E.; Urata, S.; Mizuta, H.

    1998-01-01

    In this study, the cause of inter-granular cracking in BFBs was determined from the viewpoint of the metallurgical field based upon the experimental data and information published by EdF and the direction of the development on the IASCC resistance improvement of BFB materials are investigated. From the post-irradiation examinations and basic out of pile tests for 316CW and 347 stainless, the inter-granular cracking in BFBs seems to be caused by the PWSCC due to change in the grain boundary chemical composition to low chromium, high nickel and silicon under irradiation (IASCC), but not caused by SCC due to residual oxygen in the bolt stagnant region, alkaline SCC due to the dry and wet phenomenon or now pH SCC due to oxygen concentration cell. From the PWSCC test using simulated materials of grain boundary chemical composition after irradiation, increasing of chromium, purifying and precipitating the coherent grain boundary carbides must be very effective at improving the IASCC resistance. (authors)

  18. Biomarkers of exposure to stainless steel tungsten inert gas welding fumes and the effect of exposure on exhaled breath condensate.

    Science.gov (United States)

    Riccelli, Maria Grazia; Goldoni, Matteo; Andreoli, Roberta; Mozzoni, Paola; Pinelli, Silvana; Alinovi, Rossella; Selis, Luisella; Mutti, Antonio; Corradi, Massimo

    2018-08-01

    The respiratory tract is the main target organ of the inhaled hexavalent chromium (Cr-VI) and nickel (Ni) contained in stainless steel (SS) welding fumes (WFs). The aim of this study was to investigate the Cr and Ni content of the exhaled breath condensate (EBC) of SS tungsten inert gas (TIG) welders, and relate their concentrations with oxidative stress and inflammatory biomarkers. EBC and urine from 100 SS TIG welders were collected pre-(T 0 ) and post-shift (T 1 ) on a Friday, and pre-shift (T 2 ) on the following Monday morning. Both EBC and urinary Cr concentrations were higher at T 1 (0.08 μg/L and 0.71 μg/g creatinine) and T 0 (0.06 μg/L and 0.74 μg/g creatinine) than at T 2 (below the limit of detection [LOD] and 0.59 μg/g creatinine), and EBC Ni concentrations generally remained welding also play a role in generating lung oxidative stress. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. [The effect of hydrogen peroxide on the electrochemical corrosion properties and metal ions release of nickel-chromium dental alloys].

    Science.gov (United States)

    Wang, Jue; Qiao, Guang-yan

    2013-04-01

    To investigate the effect of hydrogen peroxide on the electrochemical corrosion and metal ions release of nickel-chromium dental alloys. The corrosion resistance of nickel-chromium dental alloys was compared by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PD) methods in artificial saliva after immersed in different concentrations of hydrogen peroxide for 112 h. The metal ions released from nickel-chromium dental alloys to the artificial saliva were detected after electrochemical measurements using inductively coupled plasma mass spectrometry (ICP-MS). The data was statistically analyzed by analysis of variance (ANOVA) using SPSS 13.0 software package. The electrochemical experiment showed that the sequence of polarization resistance in equivalent circuit (Rct), corrosion potential (Ecorr), pitting breakdown potential (Eb), and the difference between Ecorr and Eb representing the "pseudo-passivation" (δE) of nickel-chromium alloys in artificial saliva was 30% alloys to the artificial saliva, and the order of the concentrations of metal ions was 0% corrosion resistance of nickel-chromium dental alloys decrease after immersed in different concentrations of hydrogen peroxide for 112 h. Nickel-chromium dental alloys are more prone to corrosion in the artificial saliva with the concentration of hydrogen peroxide increased, and more metal ions are released in the artificial saliva.

  20. Martensitic Stainless Steels Low-temperature Nitriding: Dependence of Substrate Composition

    OpenAIRE

    Ferreira, Lauro Mariano; Brunatto, Silvio Francisco; Cardoso, Rodrigo Perito

    2015-01-01

    Low-temperature plasma assisted nitriding is a very promising technique to improve surface mechanical properties of stainless steels, keeping unaltered or even improving their surface corrosion resistance. During treatment, nitrogen diffuses into the steel surface, increasing its hardness and wear resistance. In the present work the nitriding process of different martensitic stainless steels was studied. As-quenched AISI 410, 410NiMo, 416 and 420 stainless steel samples were plasma nitrided a...

  1. The high temperature oxidation behaviour of austenitic stainless steels

    International Nuclear Information System (INIS)

    Hales, R.

    1977-04-01

    High temperature annealing in a dynamic vacuum has been utilised to induce the growth of duplex oxide over the whole surface of stainless steel specimens. It is found that duplex oxide grows at a rate which does not obey a simple power law. The oxidation kinetics and oxide morphology have also been studied for a series of ternary austenitic alloys which cover a range of composition between 5 and 20% chromium. A model has been developed to describe the formation of duplex oxide and the subsequent formation of a 'healing layer' which virtually causes the oxidation process to stop. This phase tends to form at grain boundaries and a relationship has been derived for the reaction kinetics which relates the reaction rate with grain size of the substrate. (author)

  2. Corrosion behaviour of dissimilar welds between ferritic-martensitic stainless steel and austenitic stainless steel from secondary circuit of CANDU NPP

    International Nuclear Information System (INIS)

    Popa, L.; Fulger, M.; Tunaru, M.; Velciu, L.; Lazar, M.

    2016-01-01

    Corrosion damages of welds occur in spite of the fact that the proper base metal and filler metal have been correctly selected, industry codes and standards have been followed and welds have been realized with full weld penetration and have proper shape and contour. In secondary circuit of a Nuclear Power Station there are some components which have dissimilar welds. The principal criteria for selecting a stainless steel usually is resistance to corrosion, and white most consideration is given to the corrosion resistance of the base metal, additional consideration should be given to the weld metal and to the base metal immediately adjacent to the weld zone. Our experiments were performed in chloride environmental on two types of samples: non-welded (410 or W 1.4006 ferritic-martensitic steel and 304L or W 1.4307 austenitic stainless steel) and dissimilar welds (dissimilar metal welds: joints between 410 ferritic-martensitic and 304L austenitic stainless steel). To evaluate corrosion susceptibility of dissimilar welds was used electrochemical method (potentiodynamic method) and optic microscopy (microstructural analysis). The present paper follows the localized corrosion behaviour of dissimilar welds between austenitic stainless steel and ferritic-martensitic steel in solutions containing chloride ions. It was evaluated the corrosion rates of samples (welded and non-welded) by electrochemical methods. (authors)

  3. Study on tempering behaviour of AISI 410 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Gopa, E-mail: gopa_mjs@igcar.gov.in [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Das, C.R.; Albert, S.K.; Bhaduri, A.K.; Thomas Paul, V. [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Panneerselvam, G. [Chemistry Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Dasgupta, Arup [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India)

    2015-02-15

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

  4. Chromium Enrichment on P11 Ferritic Steel by Pack Cementation

    OpenAIRE

    Fauzi F. A.; Kurniawan T.; Salwani M. S.; Bin Y. S.; Harun W. S. W.

    2016-01-01

    The future thermal power plant is expected to operate at higher temperature to improve its efficiency and to reduce greenhouse gas emission. This target requires better corrosion properties of ferritic steels, which commonly used as materials for superheater and reheater of boiler tubes. In this work, chromium enrichment on the surface of ferritic steel is studied. The deposited chromium is expected to become a reservoir for the formation of chromia protective layer. Chromium was deposited on...

  5. Ultrasonic testing of austenitic stainless steel welds

    International Nuclear Information System (INIS)

    Nishino, Shunichi; Hida, Yoshio; Yamamoto, Michio; Ando, Tomozumi; Shirai, Tasuku.

    1982-05-01

    Ultrasonic testing of austenitic stainless steel welds has been considered difficult because of the high noise level and remarkable attenuation of ultrasonic waves. To improve flaw detectability in this kind of steel, various inspection techniques have been studied. A series of tests indicated: (1) The longitudinal angle beam transducers newly developed during this study can detect 4.8 mm dia. side drilled holes in dissimilar metal welds (refraction angle: 55 0 from SUS side, 45 0 from CS side) and in cast stainless steel welds (refraction angle: 45 0 , inspection frequency: 1 MHz). (2) Cracks more than 5% t in depth in the heat affected zones of fine-grain stainless steel pipe welds can be detected by the 45 0 shear wave angle beam method (inspection frequency: 2 MHz). (3) The pattern recognition method using frequency analysis technology was presumed useful for discriminating crack signals from spurious echoes. (author)

  6. Corrosion in lithium-stainless steel thermal-convection systems

    International Nuclear Information System (INIS)

    Tortorelli, P.F.; DeVan, J.H.; Selle, J.E.

    1980-01-01

    The corrosion of types 304L and 316 austenitic stainless steel by flowing lithium was studied in thermal-convection loops operated at 500 to 650 0 C. Both weight and compositional changes were measured on specimens distributed throughout each loop and were combined with metallographic examinations to evaluate the corrosion processes. The corrosion rate and mass transfer characteristics did not significantly differ between the two austenitic stainless steels. Addition of 500 or 1700 wt ppM N to purified lithium did not increase the dissolution rate or change the attack mode of type 316 stainless steel. Adding 5 wt % Al to the lithium reduced the weight loss of this steel by a factor of 5 relative to a pure lithium-thermal-convection loop

  7. Simplified Estimation of Tritium Inventory in Stainless Steel

    International Nuclear Information System (INIS)

    Willms, R. Scott

    2005-01-01

    An important part of tritium facility waste management is estimating the residual tritium inventory in stainless steel. This was needed as part of the decontamination and decommissioning associated with the Tritium Systems Test Assembly at Los Alamos National Laboratory. In particular, the disposal path for three, large tanks would vary substantially depending on the tritium inventory in the stainless steel walls. For this purpose the time-dependant diffusion equation was solved using previously measured parameters. These results were compared to previous work that measured the tritium inventory in the stainless steel wall of a 50-L tritium container. Good agreement was observed. These results are reduced to a simple algebraic equation that can readily be used to estimate tritium inventories in room temperature stainless steel based on tritium partial pressure and exposure time. Results are available for both constant partial pressure exposures and for varying partial pressures. Movies of the time dependant results were prepared which are particularly helpful for interpreting results and drawing conclusions

  8. Passivation behavior of Type 304 stainless steel in a non-aqueous alkyl carbonate solution containing LiPF6 salt

    International Nuclear Information System (INIS)

    Myung, Seung-Taek; Sasaki, Yusuke; Saito, Takamitsu; Sun, Yang-Kook; Yashiro, Hitoshi

    2009-01-01

    Passivation behavior of type 304 stainless steel in a non-aqueous alkyl carbonate solution containing LiPF 6 salt was studied using electrochemical polarization, X-ray photoelectron spectroscopy (XPS) and time of flight-secondary ion mass spectroscopy (ToF-SIMS). Cathodic polarization to 0 V vs. Li/Li + resulted in most but not complete reduction of the air-formed film from oxides to metal on the stainless steel, as confirmed by XPS. For complete elimination of the air-formed film, the surface of the stainless steel was scratched under anodic polarization conditions. At 3 V vs. Li/Li + where an anodic current peak appeared, only an indistinct layer was recognized on the newly scratched surface, according to ToF-SIMS analysis. Above 4 V vs. Li/Li + , substantial passive films were formed, which were composed of oxides and fluorides of iron and chromium. The origin of oxide was due to water contained in the non-aqueous alkyl carbonate solution, and that of fluorides were the result of the decomposition of electrolytic salt, LiPF 6 , especially at higher potential. The resultant passive films were stable in the non-aqueous alkyl carbonate solution containing LiPF 6 salt.

  9. Strengthening of stainless steel weldment by high temperature precipitation

    OpenAIRE

    Sergio Neves Monteiro; Lucio Fabio Cassiano Nascimento; Édio Pereira Lima, Jr.; Fernanda Santos da Luz; Eduardo Sousa Lima; Fábio de Oliveira Braga

    2017-01-01

    The mechanical behavior and the strengthening mechanism of stainless steel welded joints at 600 °C have been investigated. The welds were composed of AISI 304 stainless steel, as base metal, and niobium containing AISI 347 stainless steel, as weld metal. The investigation was conducted by means of creep tests. The welded specimens were subjected to both high temperature (600 °C) and long periods (up to 2000 h) under constant load, and both mechanical properties and microstructural changes in ...

  10. Chemical decontaminating method for stainless steel

    International Nuclear Information System (INIS)

    Onuma, Tsutomu; Akimoto, Hidetoshi.

    1990-01-01

    Radioactive metal wastes comprising passivated stainless steels are chemically decontaminated to such a radioactivity level as that of usual wastes. The present invention for chemically decontaminating stainless steels comprises a first step of immersing decontaminates into a sulfuric acid solution and a second step of immersing them into an aqueous solution prepared by adding oxidative metal salts to sulfuric acid, in which a portion of the surface of stainless steels as decontaminates are chemically ground to partially expose substrate materials and then the above-mentioned decontamination steps are applied. More than 90% of radioactive materials are removed in this method by the dissolution of the exposed substrate materials and peeling of cruds secured to the surface of the materials upon dissolution. This method is applicable to decontamination of articles having complicate shapes, can reduce the amount of secondary wastes after decontamination and also remarkably shorten the time required for decontamination. (T.M.)

  11. Reliability and performance evaluation of stainless and mild steel ...

    African Journals Online (AJOL)

    Reliability and performance of stainless and mild steel products in methanolic and aqueous sodium chloride media have been investigated. Weight-loss and pre-exposure methods were used. There was a higher rate of weight-loss of mild steels and stainless steels in 1% HCl methanolic solution than in aqueous NaCl ...

  12. Development of nuclear grade stainless steels at KCSSL

    International Nuclear Information System (INIS)

    Balachandran, G.; Dhere, M.; Mahadik, A.; Hinge, N.M.; Balasubramanian, V.

    2011-01-01

    Kalyani Carpenter Special Steels Ltd is an alloy steel plant, where a variety of alloy steel grades are produced for automotive, defence, nuclear and aerospace applications. The plant has developed expertise in processing of several alloy steel grades of superior quality that meets stringent specifications. Primary steel is processed through a combination of electric arc furnace, ladle furnace and vacuum degassing where stringent control over dephosphorisation, desulphurization, deoxidation is effected to get a refined high quality steel. The molten steel is cast through continuous casting of slabs or ingot casting. In grades specific to nuclear application, the primary cast products are further subjected to electroslag remelting to achieve further freedom from inclusions and to achieve a favourable solidification grain structure, which ultimately improve the hot workability of the alloy steel. Appropriate choice of slag and operating parameters are needed for realising the required ingot quality. The present study would examine the processing and quality aspects of some important grades of steels used in nuclear industry namely ferritic 9Cr-1Mo steel, martensitic stainless steels 403, 410, precipitation hardenable 17-4 PH stainless steel and austenitic 321, 316LN stainless steel, which were made and supplied for applications to Indian nuclear industry. The expertise developed in processing the steels in terms of melting, heat treatment and their relationship to structural features and mechanical properties would be highlighted. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Karaman, Ibrahim [Texas A& M Engineering Experiment Station, College Station, TX (United States); Arroyave, Raymundo [Texas A& M Engineering Experiment Station, College Station, TX (United States)

    2015-07-31

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

  14. Stainless steel in contact with food and bevarage

    Directory of Open Access Journals (Sweden)

    Sveto Cvetkovski

    2012-12-01

    Full Text Available Stainless steels are probably the most important materials in the food and beverage industries. The main reason for such broad implementation of stainless steel in contact with food are excellent properties which they possess such as corrosion resistance, resistance to high and low temperatures, very good mechanical and physical properties, aesthetic appeal, inertness of surface, durability, easy cleaning and recycling. Low thermal conductivity of these steels produces steeper temperature coefficient provoking an increased distortion, shrinkage and stresses compared with carbon steel.

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

    Science.gov (United States)

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

    2015-07-01

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

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

    Science.gov (United States)

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

    2009-12-01

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

  17. Tool degradation during sheet metal forming of three stainless steel alloys

    DEFF Research Database (Denmark)

    Wadman, Boel; Nielsen, Peter Søe; Wiklund, Daniel

    2010-01-01

    To evaluate if changes in tool design and tool surface preparation are needed when low-Ni stainless steels are used instead of austenitic stainless steels, the effect on tool degradation in the form of galling was investigated with three different types of stainless steel. The resistance to tool ...

  18. Carburization behavior of AISI 316LN austenitic stainless steel - Experimental studies and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Sudha, C. [Physical Metallurgy Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India); Sivai Bharasi, N. [Corrosion Science and Technology Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India); Anand, R. [Physical Metallurgy Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India); Shaikh, H., E-mail: hasan@igcar.gov.i [Corrosion Science and Technology Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India); Dayal, R.K. [Corrosion Science and Technology Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India); Vijayalakshmi, M. [Physical Metallurgy Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India)

    2010-07-31

    AISI type 316LN austenitic stainless steel was exposed to flowing sodium at 798 K for 16,000 h in the bi-metallic (BIM) sodium loop. A modified surface layer of 10 {mu}m width having a ferrite structure was detected from X-ray diffraction and electron micro probe based analysis. Beneath the modified surface layer a carburized zone of 60 {mu}m width was identified which was found to consist of M{sub 23}C{sub 6} carbides. A mathematical model based on finite difference technique was developed to predict the carburization profiles in sodium exposed austenitic stainless steel. In the computation, effect of only chromium on carbon diffusion was considered. Amount of carbon remaining in solution was determined from the solubility parameter. The predicted profile showed a reasonably good match with the experimental profile. Calculations were extended to simulate the thickness of the carburized layer after exposure to sodium for a period of 40 years. Attempt was also made to predict the carburization profiles based on equilibrium calculations using Dictra and Thermocalc which contain both thermodynamic and kinetic databases for the system under consideration.

  19. Process for recovering uranium

    Science.gov (United States)

    MacWood, G. E.; Wilder, C. D.; Altman, D.

    1959-03-24

    A process useful in recovering uranium from deposits on stainless steel liner surfaces of calutrons is presented. The deposit is removed from the stainless steel surface by washing with aqueous nitric acid. The solution obtained containing uranium, chromium, nickel, copper, and iron is treated with an excess of ammonium hydroxide to precipitnte the uranium, iron, and chromium and convert the nickel and copper to soluble ammonio complexions. The precipitated material is removed, dried and treated with carbon tetrachloride at an elevated temperature of about 500 to 600 deg C to form a vapor mixture of UCl/ sub 4/, UCl/sub 5/, FeCl/sub 3/, and CrCl/sub 4/. The UCl/sub 4/ is separated from this vapor mixture by selective fractional condensation at a temperature of about 500 to 400 deg C.

  20. A New Method to Produce Ni-Cr Ferroalloy Used for Stainless Steel Production

    Science.gov (United States)

    Chen, Pei-Xian; Chu, Shao-Jun; Zhang, Guo-Hua

    2016-08-01

    A new electrosilicothermic method has been proposed in the present paper to produce Ni-Cr ferroalloy, which can be used for the production of 300 series stainless steel. Based on this new process, the Ni-Si ferroalloy is first produced as the intermediate alloy, and then the desiliconization process of Ni-Si ferroalloy melt with chromium concentrate is carried out to generate Ni-Cr ferroalloy. The silicon content in the Ni-Si ferroalloy produced in the submerged arc furnace should be more than 15 mass% (for the propose of reducing dephosphorization), in order to make sure the phosphorus content in the subsequently produced Ni-Cr ferroalloy is less than 0.03 mass%. A high utilization ratio of Si and a high recovery ratio of Cr can be obtained after the desiliconization reaction between Ni-Si ferroalloy and chromium concentrate in the electric arc furnace (EAF)-shaking ladle (SL) process.

  1. Improvement in mechanical properties of chromium-nickel sintered compacts by repeated rolling and annealing; Kuromu nickel shoketsuzai no kurikaeshi atsuen shodon ni yoru kikaiteki seishitsu no kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Y. [Toyohashi University of Technology, Aichi (Japan); Omori, M. [Hiroshima-Denki Institute of Technology, Hiroshima (Japan); Ando, H. [Nippon Steel Glass Co. Ltd., Tokyo (Japan); Matsui, H. [Tadano Ltd., Kagawa (Japan); Okita, T. [Honda R and D Co. Ltd., Tokyo (Japan)

    1998-09-20

    Chromium-nickel sintered compacts containing 50 and 80 mass%Cr were tried to improve their mechanical properties by means of a thermo-mechanical treatment, i.e., repeated rolling and annealing. Specimens from the as-sintered compacts showed no ductility at room temperature and small ductility at temperatures higher than 1000 K because of poor alloying of nickel with chromium. Tensile properties of the sheets repeatedly rolled with the intermediate annealing at 1173 K were very similar to those of the as-sintered specimen. While the sheets rolled with the annealing at 1573 K were excellently improved in their strength and ductility due to the considerable interdiffusion of chromium and nickel. The intermediate temperature embrittlement, that is, the ductility minimum well observed around 1000 K in a chromium-nickel alloy appeared also in the sheets rolled with the annealing at 1573 K. 15 refs., 13 figs., 1 tab.

  2. Metal-ceramic joint assembly

    Science.gov (United States)

    Li, Jian

    2002-01-01

    A metal-ceramic joint assembly in which a brazing alloy is situated between metallic and ceramic members. The metallic member is either an aluminum-containing stainless steel, a high chromium-content ferritic stainless steel or an iron nickel alloy with a corrosion protection coating. The brazing alloy, in turn, is either an Au-based or Ni-based alloy with a brazing temperature in the range of 9500 to 1200.degree. C.

  3. Effects of microstructure on ultrasonic examination of stainless steel

    International Nuclear Information System (INIS)

    Kupperman, D.S.; Reimann, K.J.

    1976-01-01

    Ultrasonic inspection of cast stainless steel components or stainless steel welds is difficult, and the results obtained are hard to interpret. The present study describes the effects of stainless steel microstructure on ultrasonic test results. Welded coupons, 2.5 and 5.0 cm thick, were fabricated from Type 304 stainless steel, with Type 308 stainless steel as the weld material. Metallography of the base material shows grain sizes of 15 and 80 μm, and dendrites aligned from the top to the bottom surface in cast material. X-ray diffraction and ultrasonic velocity measurements indicate a random crystal orientation in the base material, but the cast sample had aligned dendrites. The weld material exhibits a dendritic structure with a preferred (100) direction perpendicular to the weld pass. Spectral analysis of ultrasonic broad-band signals through the base materials shows drastic attenuation of higher frequencies with increasing grain size (Rayleigh scattering). Annealing and recrystallization increases the ultrasonic attenuation and produces carbide precipitation at grain boundaries. The microstructural differences of the base metal, heat-affected zone, and weld metal affect the amplitude of ultrasonic reflections from artificial flaws in these zones. Data obtained from two samples of different grain sizes indicate that grain size has little effect when a 1-MHz transducer is used. When going from a 15 to an 80-μm crystalline structure, a 5-MHz unit suffers a 30-dB attenuation in the detection of a 1.2 mm deep notch. The anisotropy of the dendritic structure in stainless steel renewed the interest in the effect of shear-wave polarization. In the (110) crystallographic orientation of stainless steel, two modes of shear waves can be generated, which have velocities differing by a factor of two. This effect may be helpful in ''tuning'' of shear waves by polarization to obtain better penetration in large grain materials such as welds

  4. Material physical properties of 12 chromium ferritic steel

    International Nuclear Information System (INIS)

    Ando, Masanori; Wakai, Takashi; Aoto, Kazumi

    2003-09-01

    High chromium ferritic steel is an attractive candidate for structural material of the next Fast Breeder Reactor, since both of thermal properties and high temperature strength of the steel are superior to those of conventional austenitic stainless steels. In this study, physical properties of 12Cr steels are measured and compared to those obtained in the previous studies to discuss about stochastic dispersions. The effect of measurement technique on Young's modulus and the influence of the specimen size on coefficient of thermal expansion are also investigated. The following conclusions are obtained. (1) Young's modulus of 12Cr steels obtained in this study tends to larger than those obtained in the previous studies especially in high temperature. Such a discrepancy is resulted from the difference in measurement technique. It was clarified that Young's modulus obtained by free vibration method is more adequate those obtained by the cantilever characteristic vibration method. Therefore, the authors recommend using the values obtained by free vibration method as Young's modulus of 12Cr steels. (2) Both instant and mean coefficient of thermal expansion of 12Cr steels obtained in this study is in a good agreement with those obtained in the previous studies. However, the obviously different values are obtained from the measurement by large size specimens. Such a discrepancy is resulted from heterogeneous during heating process of the specimens. Therefore, the authors recommend using the values obtained by φ4 x 20 mm specimens as instant and mean coefficient of thermal expansion of 12Cr steels. (3) Specific heat of 12Cr steels obtained in this study agree with those obtained in the previous studies with a few exceptions. (4)Thermal conductivity of 12Cr steels obtained in this study agree with those obtained in the previous studies. (5) It was confirmed that instant and mean coefficient of thermal expansion, density, specific heat and thermal conductivity of 12Cr steels

  5. Behaviour of stainless steel in natural seawater

    OpenAIRE

    Compere, Chantal; Le Bozec, Nathalie

    1997-01-01

    In this paper, investigations performed in natural and artificial seawater on stainless steels will be presented. They concerned studies on: biofilm formation, passive layers composition, electrochemical behaviour, localised corrosion and the evolution of these different parameters as a function of ageing time. According to literature surveys, the different aspects will be discussed. Some conclusions will be drawn concerning the actual knowledge on the behaviour of stainless steels in seawater.

  6. NDE of explosion welded copper stainless steel first wall mock-up

    International Nuclear Information System (INIS)

    Taehtinen, S.; Kauppinen, P.; Jeskanen, H.; Lahdenperae, K.; Ehrnsten, U.

    1997-04-01

    The study showed that reflection type C-mode scanning acoustic microscope (C-SAM) and internal ultrasonic inspection (IRIS) equipment can be applied for ultrasonic examination of copper stainless steel compound structures of ITER first wall mock-ups. Explosive welding can be applied to manufacture fully bonded copper stainless steel compound plates. However, explosives can be applied only for mechanical tightening of stainless steel cooling tubes within copper plate. If metallurgical bonding between stainless steel tubes and copper plate is required Hot Isostatic Pressing (HIP) method can be applied. (orig.)

  7. Embrittlement and life prediction of aged duplex stainless steel

    International Nuclear Information System (INIS)

    Kuwano, Hisashi

    1996-01-01

    The stainless steel, for which the durability for long term in high temperature corrosive environment is demanded, is a complex plural alloy. Cr heightens the oxidation resistance, Ni improves the ductility and impact characteristics, Si improves the fluidity of the melted alloy and heightens the resistance to stress corrosion cracking, and Mo suppresses the pitting due to chlorine ions. These alloy elements are in the state of nonequilibrium solid solution in Fe base at practical temperature, and cause aging phenomena such as segregation, concentration abnormality and precipitation during the use for long term. The characteristics of stainless steel deteriorate due to this. Two-phase stainless cast steel, the example of the embrittlement of the material for an actual machine, the accelerated test of embrittlement, the activation energy for embrittlement, and as the mechanism of aging embrittlement, the spinodal decomposition of ferrite, the precipitation of G phase and the precipitation of carbides and nitrides are described. Also in the welded parts of austenitic stainless steel, delta-ferrite is formed during cooling, therefore, the condition is nearly same as two-phase stainless steel, and the embrittlement due to long term aging occurs. (K.I.)

  8. Strengthening of stainless steel weldment by high temperature precipitation

    Directory of Open Access Journals (Sweden)

    Sergio Neves Monteiro

    2017-10-01

    Full Text Available The mechanical behavior and the strengthening mechanism of stainless steel welded joints at 600 °C have been investigated. The welds were composed of AISI 304 stainless steel, as base metal, and niobium containing AISI 347 stainless steel, as weld metal. The investigation was conducted by means of creep tests. The welded specimens were subjected to both high temperature (600 °C and long periods (up to 2000 h under constant load, and both mechanical properties and microstructural changes in the material were monitored. It was found that the exposure of the material at 600 °C under load contributes to a strengthening effect on the weld. The phenomenon might be correlated with an accelerated process of second phase precipitation hardening. Keywords: Stainless steel, Weld, AISI 304, Precipitation hardening

  9. Cathodic protection of steel by electrodeposited zinc-nickel alloy coatings

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, K.R.; Smith, C.J.E. [Defence Research Agency, Farnborough (United Kingdom). Structural Materials Centre; Robinson, M.J. [Cranfield Univ. (United Kingdom). School of Industrial and Manufacturing Science

    1995-12-01

    The ability of electrodeposited zinc-nickel alloy coatings to cathodically protect steel was studied in dilute chloride solutions. The potential distribution along steel strips partly electroplated with zinc-nickel alloys was determined, and the length of exposed steel that was held below the minimum protection potential (E{sub prot}) was taken as a measure of the level of cathodic protection (CP) provided by the alloy coatings. The level of CP afforded by zinc alloy coatings was found to decrease with increasing nickel content. When nickel content was increased to {approx} {ge} 21 wt%, no CP was obtained. Surface analysis of uncoupled zinc-nickel alloys that were immersed in sodium chloride (NaCl) solutions showed the concentration of zinc decreased in the surface layers while the concentration of nickel increased, indicating that the alloys were susceptible to dezincification. The analysis of zinc-nickel alloy coatings on partly electroplated steel strips that were immersed in chloride solution showed a significantly higher level of dezincification than that found for uncoupled alloy coatings. This effect accounted for the rapid loss of CP afforded to steel by some zinc alloy coatings, particularly those with high initial nickel levels.

  10. Biosorption characteristics of copper (II), chromium (III), nickel (II), and lead (II) from aqueous solutions by Chara sp. and Cladophora sp.

    Science.gov (United States)

    Elmaci, Ayşe; Yonar, Taner; Ozengin, Nihan

    2007-09-01

    The aim of this research was to expose individual removals of copper, chromium, nickel, and lead from aqueous solutions via biosorption using nonliving algae species, Chara sp. and Cladophora sp. Optimum pH values for biosorption of copper (II), chromium (III), nickel (II), and lead (II) from aqueous solutions were determined to be 6, 7, 7, and 3 for Cladophora sp. and 5, 3, 5, and 4 for Chara sp. respectively. Maximum adsorption capacities of Chara sp. [10.54 for chromium (III) and 61.72 for lead (II)] and Cladophora sp. [6.59 for chromium (III) and 16.75 and 23.25 for lead (II)] for chromium (III) and lead (II) are similar. On the other hand, copper (II) and nickel (II) biosorption capacity of Cladophora sp. [14.28 for copper (II) and 16.75 for nickel (II)] is greater than Chara sp. [6.506 for copper (II) and 11.76 for nickel (II)]. Significantly high correlation coefficients indicated for the Langmuir adsorption isotherm models can be used to describe the equilibrium behavior of copper, chromium, nickel, and lead adsorption onto Cladophora sp. and Chara sp.

  11. Damage evolution and failure mechanisms in additively manufactured stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Carlton, Holly D., E-mail: carlton4@llnl.gov [Materials Engineering Division, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Haboub, Abdel [Lincoln University, Life and Physical Sciences Department, 820 Chestnut St, Jefferson City, MO 65101 (United States); Gallegos, Gilbert F. [Materials Engineering Division, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Parkinson, Dilworth Y.; MacDowell, Alastair A. [Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

    2016-01-10

    In situ tensile tests were performed on additively manufactured austenitic stainless steel to track damage evolution within the material. For these experiments Synchrotron Radiation micro-Tomography was used to measure three-dimensional pore volume, distribution, and morphology in stainless steel at the micrometer length-scale while tensile loading was applied. The results showed that porosity distribution played a larger role in affecting the fracture mechanisms than measured bulk density. Specifically, additively manufactured stainless steel specimens with large inhomogeneous void distributions displayed a flaw-dominated failure where cracks were shown to initiate at pre-existing voids, while annealed additively manufactured stainless steel specimens, which contained low porosity and randomly distributed pores, displayed fracture mechanisms that closely resembled wrought metal.

  12. Relationship between nickel allergy and diet

    OpenAIRE

    Sharma Ashimav

    2007-01-01

    Nickel is a ubiquitous trace element and it occurs in soil, water, air and of the biosphere. It is mostly used to manufacture stainless steel. Nickel is the commonest cause of metal allergy. Nickel allergy is a chronic and recurring skin problem; females are affected more commonly than males. Nickel allergy may develop at any age. Once developed, it tends to persist life-long. Nickel is present in most of the dietary items and food is considered to be a major source of nickel exposure for the...

  13. Nanosecond laser surface modification of AISI 304L stainless steel: Influence the beam overlap on pitting corrosion resistance

    International Nuclear Information System (INIS)

    Pacquentin, Wilfried; Caron, Nadège; Oltra, Roland

    2014-01-01

    Surface modifications of AISI 304L stainless steel by laser surface melting (LSM) were investigated using a nanosecond pulsed laser-fibre doped by ytterbium at different overlaps. The objective was to study the change in the corrosion properties induced by the treatment of the outer-surface of the stainless steel without modification of the bulk material. Different analytical techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and glow discharge optical emission spectrometry (GDOES) were used to characterize the laser-melted surface. The corrosion resistance was evaluated in a chloride solution at room temperature by electrochemical tests. The results showed that the crystallographic structure, the chemical composition, the properties of the induced oxide layer and consequently the pitting corrosion resistance strongly depend on the overlap rate. The most efficient laser parameters led to an increase of the pitting potential by more than 300 mV, corresponding to a quite important improvement of the corrosion resistance. This latter was correlated to chromium enrichment (47 wt.%) at the surface of the stainless steel and the induced absence of martensite and ferrite phases. However, these structural and chemical modifications were not sufficient to explain the change in corrosion behaviour: defects and adhesion of the surface oxide layer must have been taken into consideration.

  14. Standard test method for electrochemical critical pitting temperature testing of stainless steels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 This test method covers a procedure for the evaluation of the resistance of stainless steel and related alloys to pitting corrosion based on the concept of the determination of a potential independent critical pitting temperature (CPT). 1.2 This test methods applies to wrought and cast products including but not restricted to plate, sheet, tubing, bar, forgings, and welds, (see Note 1). Note 1—Examples of CPT measurements on sheet, plate, tubing, and welded specimens for various stainless steels can be found in Ref (1). See the research reports (Section 14). 1.3 The standard parameters recommended in this test method are suitable for characterizing the CPT of austenitic stainless steels and other related alloys with a corrosion resistance ranging from that corresponding to solution annealed UNS S31600 (Type 316 stainless steel) to solution annealed UNS S31254 (6 % Mo stainless steel). 1.4 This test method may be extended to stainless steels and other alloys related to stainless steel that have a CPT...

  15. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    OpenAIRE

    Prabhu Paulraj; Rajnish Garg

    2015-01-01

    Duplex Stainless Steels (DSS) and Super Duplex Stainless Steel (SDSS) have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic pha...

  16. Aluminide Coating on Stainless Steel for Nuclear Reactor Application: A Preliminary Study

    International Nuclear Information System (INIS)

    Hishamuddin Husain; Zaifol Samsu; Yusof Abdullah; Muhamad Daud

    2015-01-01

    Stainless steels have been used as structural materials in the nuclear reactor since its first generation. Stainless steels type 304 and 316 are commonly used in structural components. Since the first generation materials, improvements were made on Stainless steels. This includes addition of stabilizing elements and by modification of metallurgical structure. This study investigates the formation of aluminide coating on Stainless steels by diffusion to help improve corrosion resistance. Stainless steels type 304 and 316 substrates were immersed in molten aluminium at 750 degree Celsius for 5 minutes. Interaction between molten aluminium and solid to form the outer aluminide coating by hot dipped aluminizing is studied. (Author)

  17. Advances in stainless steels

    International Nuclear Information System (INIS)

    Baldev Raj; Jayakumar, T.; Saibaba, Saroja; Sivaprasad, P.V.; Shankar, P.

    2010-01-01

    This book covers a broad spectrum of topics spanning the entire life cycle of stainless steel-from alloy design and characterization to engineering design, fabrication, mechanical properties, corrosion, quality assurance of components, in-service performance assessment, life prediction and finally failure analysis of materials and components. The contents provide useful feedback for further developments aimed at effective utilization of this class of materials. The book comprises articles that bring out contemporary developments in stainless steels and is thematically classified into the following sections. 1. Component design, modelling and structural integrity, 2. Manufacturing technology, 3. Property evaluation, 4. Alloy development and applications, 5. NDE methods, 6. Corrosion and surface modification. The book commences with articles on component design and structural integrity, thus opening up the areas of challenge for researchers and academia. The articles in the book relevant to INIS are indexed separately

  18. TiC-Maraging stainless steel composite: microstructure, mechanical and wear properties

    Institute of Scientific and Technical Information of China (English)

    Akhtar Farid; GUO Shiju; FENG Peizhong; Khadijah Ali Shah; Syed Javid Askari

    2006-01-01

    Particulate TiC reinforced 17-4PH and 465 maraging stainless steel matrix composites were processed by conventional powder metallurgy (P/M). TiC-maraging stainless steel composites with theoretical density >97% were produced using conventional P/M. The microstructure, and mechanical and wear properties of the composites were evaluated. The microstructure of the composites consisted of (core-rim structure) spherical and semi-spherical TiC particles depending on the wettability of the matrix with TiC particles. In TiC-maraging stainless steel composites, 465 stainless steel binder phase showed good wettability with TiC particles. Some microcracks appeared in the composites, indicating the presence of tensile stresses in the composites produced during sintering. The typical properties, hardness, and bend strength were reported for the composites. After heat treatment and aging, an increase in hardness was observed. The increase in hardness was attributed to the aging reaction in maraging stainless steel. The specific wear behavior of the composites strongly depends on the content of TiC particles and their interparticle spacing, and on the heat treatment of the maraging stainless steel.

  19. Environmentally assisted cracking of non-sensitized stainless steels - possible affecting phenomena

    International Nuclear Information System (INIS)

    Ehrnsten, Ulla; Haenninen, Hannu

    2006-09-01

    Intergranular, environmentally assisted cracking (EAC) has been observed, not only in sensitized austenitic stainless steels, but also in non-sensitized stainless steels. This type of cracking has so far been connected to cold-worked stainless steels and it has been reported to occur in the oxidising environments, but it may also be a potential degradation mode in non-oxidising environments (i.e., both in BWR and PWR conditions). Localisation of plastic deformation and the interactions between oxidation and strain localisation are most probably playing the key role in cracking of cold-worked stainless steels. In this paper, the possible affecting phenomena are reviewed with the main emphasis on dynamic strain ageing. However, also environmentally enhanced creep, dynamic recovery, microstructures of the cold-worked austenitic stainless steels and relaxation are briefly discussed. Mechanistic understanding of the effects of these main factors affecting intergranular stress corrosion cracking of cold-worked, non-sensitized austenitic stainless steels is important, especially as the trend in the NDE inspection strategy is moving towards risk informed inspection. (authors)

  20. Parallel between steels alloyed with chrome-nickel and Fe-Mn-Al-C steels, in their response to fracture and wear (Review)

    International Nuclear Information System (INIS)

    Ramos, J; Perez, G.A

    2008-01-01

    The big worldwide demand for chrome-nickel alloy steels ('conventional steel') leads to the need for advanced materials for applications in different engineering systems that operate at high temperatures and in aggressive environmental conditions, favoring research and development in alternate alloys. In this technological race in search of these new materials, the FeMnAlC alloys ('new steels') have attracted attention for their excellent mechanical and tribological properties as well as for their good performance in corrosive-oxide environments, which make them similar to conventional steel. There are two important similarities between these two steels. First, an agent that causes the passive film to become stainless appears in both steels: chrome in the conventional steel, and aluminum in the FeMnAl alloy. The second similarity is that a stabilizing agent of the austenitic phase (FCC) appears in both, so that excellent mechanical properties can be obtained: nickel in the conventional steel, and manganese in the FeMnAl alloy. In certain sectors, such as aeronautics, conventional steel is rarely used because it is a very heavy material. This conventional steel is almost three times heavier that aluminum (7.85/2.7). Two advantages that the new FeMnAIC steels have compared to the conventional steels are that they are about 13% lighter in weight and they are less expensive. The FeMnAl also have excellent mechanical properties and good corrosion-oxidation resistance, which generates big expectations for their application in a broad scientific spectrum. This work reports the state of the information currently available about FeMnAlC alloys, comparing the mechanical and tribological behaviors of conventional alloy steels with chrome and nickel alloys, specifying the scopes of their application. A condition that favors the steels' fragility is the high speed of deformation and impact, where the FCC crystalline structure materials do not have a fragile ductile transition

  1. Effect of the oxygen partial pressure on ferritic stainless steel AISI 441 at high temperatures

    International Nuclear Information System (INIS)

    Salgado, M.F.; Carvalho, I.S.; Santos, R.S.; Correa, O.V.; Ramanathan, L.V.

    2014-01-01

    Stainless steels can be exposed to aggressive gases at high temperatures. To understand the behavior of oxidation of the steel AISI 441 was made oxidation at temperatures between 850 ° C and 950 ° C, at two different atmospheres: synthetic air, using tubular furnace and Argon, containing 1ppm O_2, in thermobalance. The kinetics of oxidation of the films was established by measuring the mass gain per unit of area as a function of the oxidation time. The microstructure and chemical composition of the oxides were analyzed by SEM, EDS and XRD. Chemical analysis showed that films formed on steel AISI 441 had mostly chromium oxide and the following elements: Cr, Mn, Fe, Ti and Si. Regarding the kinetics of oxidation, it was observed that in synthetic air, the steel oxidation increased gradually with the temperature, but in argon, it showed the highest oxidation at 900 ° C and the lowest oxidation at 950 ° C. (author)

  2. The effects of a common stainless steel orthodontic bracket on the diagnostic quality of cranial and cervical 3T- MR images: a prospective, case-control study.

    Science.gov (United States)

    Cassetta, Michele; Pranno, Nicola; Stasolla, Alessandro; Orsogna, Nicola; Fierro, Davide; Cavallini, Costanza; Cantisani, Vito

    2017-08-01

    To evaluate the effect of orthodontic stainless steel brackets and two different types of archwires on the diagnostic quality of 3-T MR images. This prospective, case-control study was conducted following Strengthening the Reporting of Observational Studies in Epidemiology guidelines. The recruitment was conducted among orthodontic patients. 80 subjects, requiring MRI for the presence of temporomandibular disorders, were enrolled and divided into four groups: 20 patients using aligners (control group); 20 patients with stainless steel brackets without archwires; 20 patients with stainless steel brackets and nickel-titanium archwires; and 20 patients with stainless steel brackets and stainless steel archwires. Two experts in neuroradiology evaluated the images to determine the amount of distortion in 6 regions and 48 districts. A score was subjectively assigned according to a modified receiver operating characteristic method of distortion classification. Any disagreement was resolved through consensus seeking; when this was not possible, a third neuroradiologist was consulted. The following statistical methods were used: descriptive statistics, Cohen's kappa coefficient (k), Kruskal-Wallis test, pairwise comparisons using the Dunn-Bonferroni approach. The significance was set at p ≤ 0.05. The presence of stainless steel brackets with or without archwires negatively influenced MRI of the cervical region, paranasal sinuses, head and neck region, and cervical vertebrae but did not influence MRI of brain and temporomandibular joint regions. Patients with a stainless steel multibracket orthodontic appliance should remove it before cervical vertebrae, cervical region, paranasal sinuses, and head and neck MRI scans. The brain and temporomandibular joint region MRI should not require the removal of such appliances.

  3. HIP bonding for the different material between Niobium and Stainless steel

    International Nuclear Information System (INIS)

    Inoue, H.; Saito, K.; Abe, K.; Fujino, T.; Hitomi, N.; Kobayashi, Y.

    2000-01-01

    In the future advanced cryomodule for superconducting RF cavities, a helium vessel made from titanium or stainless steel has to be welded directly to the niobium cavity wall in order to be simple structure. For that, we need a transformer from niobium to titanium or stainless steel. Stainless steel will have many benefits if the reliable bonding to the niobium is developed. We have tested the niobium/stainless steel bonding by HIP (Hot Isostatic Pressing) with the heat shock between 1023K and 2K. The bonding interface was also observed by SEM. These test results will be presented. (author)

  4. Applications of nitrogen-alloyed stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Sundvall, J.; Olsson, J. [Avesta Sheffield AB (Sweden); Holmberg, B. [Avesta Welding AB (Sweden)

    1999-07-01

    A selected number of applications for different types of nitrogen-alloyed stainless steels are described. The applications and grades are based on how nitrogen improves different properties. Conventional austenitic grades of type 304 and 316 can be alloyed with nitrogen to increase the strength and to maintain the austenite stability after cold deformation when exposed to cryogenic temperatures. Such examples are presented. The addition of nitrogen to duplex grades of stainless steel such as 2205 improves the pitting resistance, among other things, and also enables faster reformation of the austenite in the heat affected zone. This means that heavy plate can be welded without pre-heating or post-weld heating. Such applications are covered. Modern highly alloyed austenitic stainless steels almost always contain nitrogen and all reasons for this are covered, i.e. to stabilise the austenite, to increase the strength, and to improve the pitting resistance. The increased strength is the characteristic exemplified the least, since the higher strength of duplex grades is well known, but examples on austenite stability and improved pitting resistance are presented. (orig.)

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

    International Nuclear Information System (INIS)

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

    1995-01-01

    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

  6. Characterization and assessment of dermal and inhalable nickel exposures in nickel production and primary user industries.

    Science.gov (United States)

    Hughson, G W; Galea, K S; Heim, K E

    2010-01-01

    The aim of this study was to measure the levels of nickel in the skin contaminant layer of workers involved in specific processes and tasks within the primary nickel production and primary nickel user industries. Dermal exposure samples were collected using moist wipes to recover surface contamination from defined areas of skin. These were analysed for soluble and insoluble nickel species. Personal samples of inhalable dust were also collected to determine the corresponding inhalable nickel exposures. The air samples were analysed for total inhalable dust and then for soluble, sulfidic, metallic, and oxidic nickel species. The workplace surveys were carried out in five different workplaces, including three nickel refineries, a stainless steel plant, and a powder metallurgy plant, all of which were located in Europe. Nickel refinery workers involved with electrolytic nickel recovery processes had soluble dermal nickel exposure of 0.34 microg cm(-2) [geometric mean (GM)] to the hands and forearms. The GM of soluble dermal nickel exposure for workers involved in packing nickel salts (nickel chloride hexahydrate, nickel sulphate hexahydrate, and nickel hydroxycarbonate) was 0.61 microg cm(-2). Refinery workers involved in packing nickel metal powders and end-user powder operatives in magnet production had the highest dermal exposure (GM = 2.59 microg cm(-2) soluble nickel). The hands, forearms, face, and neck of these workers all received greater dermal nickel exposure compared with the other jobs included in this study. The soluble nickel dermal exposures for stainless steel production workers were at or slightly above the limit of detection (0.02 microg cm(-2) soluble nickel). The highest inhalable nickel concentrations were observed for the workers involved in nickel powder packing (GM = 0.77 mg m(-3)), although the soluble component comprised only 2% of the total nickel content. The highest airborne soluble nickel exposures were associated with refineries using

  7. Corrosion resistance of stainless steel pipes in soil

    Energy Technology Data Exchange (ETDEWEB)

    Sjoegren, L.; Camitz, G. [Swerea KIMAB AB, Box 55970, SE-102 16 Stockholm (Sweden); Peultier, J.; Jacques, S.; Baudu, V.; Barrau, F.; Chareyre, B. [Industeel and ArcelorMittal R and D, 56 rue Clemenceau, BP19, FR-71201 le Creusot, Cedex (France); Bergquist, A. [Outokumpu Stainless AB, P.O. Box 74, SE-774 22 Avesta (Sweden); Pourbaix, A.; Carpentiers, P. [Belgian Centre for Corrosion Study, Avenue des Petits-Champs 4A, BE 1410 Waterloo (Belgium)

    2011-04-15

    To be able to give safe recommendations concerning the choice of suitable stainless steel grades for pipelines to be buried in various soil environments, a large research programme, including field exposures of test specimens buried in soil in Sweden and in France, has been performed. Resistance against external corrosion of austenitic, super austenitic, lean duplex, duplex and super duplex steel grades in soil has been investigated by laboratory tests and field exposures. The grades included have been screened according to their critical pitting-corrosion temperature and according to their time-to-re-passivation after the passive layer has been destroyed locally by scratching. The field exposures programme, being the core of the investigation, uses large specimens: 2 m pipes and plates, of different grades. The exposure has been performed to reveal effects of aeration cells, deposits or confined areas, welds and burial depth. Additionally, investigations of the tendency of stainless steel to corrode under the influence of alternating current (AC) have been performed, both in the laboratory and in the field. Recommendations for use of stainless steels under different soil conditions are given based on experimental results and on operating experiences of existing stainless steel pipelines in soil. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. A study of the prospects for development of low-activation martensitic stainless steels for first-wall and blanket structures in fusion reactors

    International Nuclear Information System (INIS)

    Tupholme, K.W.; Orr, J.; Dulieu, D.; Butterworth, G.J.

    1986-04-01

    This study examines the potential of the elemental substitution approach to the design of low-activity martensitic stainless steels, subject to the requirement that the contact γ dose rate falls to a value that would allow essentially unrestricted handling of discarded material after a cooling period of 100 years. The factors governing the structure and properties of the 9-12%Cr martensitic steels are reviewed. Practicable substitutes for the proscribed elements molybdenum, nickel and niobium include tungsten, tantalum and an increased vanadium content in conjunction with optimised carbon, nitrogen and boron levels. Given the generally attractive combination of properties offered by the martensitic steels, the prospects for developing a satisfactory low-activity composition appear favourable. A series of experimental compositions and a programme of investigations are proposed to explore possible alloys with the objective of reproducing, as far as possible, the characteristics of existing fully martensitic high strength stainless steels. (author)

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

    Science.gov (United States)

    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.

  10. Optimization of the A-TIG welding for stainless steels

    Science.gov (United States)

    Jurica, M.; Kožuh, Z.; Garašić, I.; Bušić, M.

    2018-03-01

    The paper presents the influence of the activation flux and shielding gas on tungsten inert gas (A-TIG) welding of the stainless steel. In introduction part, duplex stainless steel was analysed. The A-TIG process was explained and the possibility of welding stainless steels using the A-TIG process to maximize productivity and the cost-effectiveness of welded structures was presented. In the experimental part duplex, 7 mm thick stainless steel has been welded in butt joint. The influence of activation flux chemical composition upon the weld penetration has been investigated prior the welding. The welding process was performed by a robot with TIG equipment. With selected A-TIG welding technology preparation of plates and consumption of filler material (containing Cr, Ni and Mn) have been avoided. Specimens sectioned from the produced welds have been subjected to tensile strength test, macrostructure analysis and corrosion resistance analysis. The results have confirmed that this type of stainless steel can be welded without edge preparation and addition of filler material containing critical raw materials as Cr, Ni and Mn when the following welding parameters are set: current 200 A, welding speed 9,1 cm/min, heat input 1,2 kJ/mm and specific activation flux is used.

  11. Antibacterial effect of silver nanofilm modified stainless steel surface

    Science.gov (United States)

    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.

  12. Microstructure and mechanical properties of resistance upset butt welded 304 austenitic stainless steel joints

    International Nuclear Information System (INIS)

    Sharifitabar, M.; Halvaee, A.; Khorshahian, S.

    2011-01-01

    Graphical abstract: Three different microstructural zones formed at different distances from the joint interface in resistance upset butt welding of 304 austenitic stainless steel. Highlights: → Evaluation of microstructure in resistance upset welding of 304 stainless steel. → Evaluation of welding parameters effects on mechanical properties of the joint. → Introducing the optimum welding condition for joining stainless steel bars. -- Abstract: Resistance upset welding (UW) is a widely used process for joining metal parts. In this process, current, time and upset pressure are three parameters that affect the quality of welded products. In the present research, resistance upset butt welding of 304 austenitic stainless steel and effect of welding power and upset pressure on microstructure, tensile strength and fatigue life of the joint were investigated. Microstructure of welds were studied using scanning electron microscopy (SEM). X-ray diffraction (XRD) analysis was used to distinguish the phase(s) that formed at the joint interface and in heat affected zone (HAZ). Energy dispersive spectroscopy (EDS) linked to the SEM was used to determine chemical composition of phases formed at the joint interface. Fatigue tests were performed using a pull-push fatigue test machine and the fatigue properties were analyzed drawing stress-number of cycles to failure (S-N) curves. Also tensile strength tests were performed. Finally tensile and fatigue fracture surfaces were studied by SEM. Results showed that there were three different microstructural zones at different distances from the joint interface and delta ferrite phase has formed in these regions. There was no precipitation of chromium carbide at the joint interface and in the HAZ. Tensile and fatigue strengths of the joint decreased with welding power. Increasing of upset pressure has also considerable influence on tensile strength of the joint. Fractography of fractured samples showed that formation of hot spots at

  13. Evolution of stainless steels in nuclear industry

    International Nuclear Information System (INIS)

    Tavassoli, Farhad

    2010-01-01

    Starting with the stainless steels used in the conventional industry, their adoption and successive evolutions in the nuclear industry, from one generation of nuclear reactors to another, is presented. Specific examples for several steels are given, covering fabrication procedures, qualification methods, property databases and design allowable stresses, to show how the ever-increasing demands for better performance and reliability, in particular under neutron irradiation, have been met. Particular attention is paid to the austenitic stainless steels types 304L, 316L, 316L(N), 316L(N)-IG, titanium stabilized grade 321, precipitation strengthened alloy 800, conventional and low activation ferritic/martensitic steels and their oxygen dispersion strengthening (ODS) derivatives. For each material, the evolution of the associated filler metal and welding techniques are also presented. (author)

  14. Microstructure, Corrosion and Magnetic Behavior of an Aged Dual-Phase Stainless Steel

    Science.gov (United States)

    Ziouche, A.; Haddad, A.; Badji, R.; Zergoug, M.; Zoubiri, N.; Bedjaoui, W.; Abaidia, S.

    2018-03-01

    In the present work, the effect of the precipitation phenomena on corrosion and magnetic behavior of an aged dual-phase stainless steel was investigated. Aging treatment caused the precipitation of the σ phase, chromium carbides and secondary austenite, which was accompanied by the shifting of the δ/γ interfaces inside the δ ferrite grains. Aging between 700 and 850 °C strongly deteriorated the pitting corrosion resistance of the studied material. Magnetic investigation of the aged material using the vibration sample magnetic technique revealed the sensitivity of the intrinsic magnetic properties to the smallest microstructural change. This was confirmed by the Eddy current technique that led also to the evaluation of the aging-induced localized corrosion.

  15. Method of chemical decontamination of stainless steel

    International Nuclear Information System (INIS)

    Onuma, Tsutomu; Akimoto, Hidetoshi.

    1989-01-01

    The present invention concerns a decontamination method of chemically decontaminating radioactive metal wastes of passivated stainless steels to a radioactivity level identical with usual wastes, in which the amount of oxidizable metal salts used is decreased. Metal wastes of stainless steels contaminated at their surface with radioactive materials are immersed in a sulfuric acid solution. In this case, a voltage is applied for a certain period of time so that the potential of the stainless steels comes to an active region. Then, oxidizable metal salt (tetravalent cerium) is added into the sulfuric acid solution. According to this method, since most of radioactive materials are removed in the immersing step to the sulfuric acid solution, the amount of the tetravalent cerium used is as less as 1/700 and the decontamination time is as short as 1/4 as compared with those in the conventional method. (K.M.)

  16. Compresibility and sinterability of HCx PM steel diluted with stainless steels

    Directory of Open Access Journals (Sweden)

    Elena Gordo

    2003-12-01

    Full Text Available HCx powder metallurgy steel contains in its composition high contents of Cr and C, and significant quantities of alloy elements typical of tool steels (Mo, V, W, to provide the corrosion resistance of stainless steel with wear resistance of tool steels. HCx appears to be a suitable material for applications in aggressive environments, as valve seat inserts in automotive engines. However, this steel presents a low compressibility leading to high production costs. In this work, some results carried out to improve the compressibility of HCx are presented. The way to attempt this improvement is the dilution of base material with two stainless steels, the ferritic 430LHC and the austenitic 316L. The powder mixes prepared were uniaxially pressed to study the compressibility. The sinterability was study by determining of density, hardness, transverse rupture strength (TRS and microstructural evolution after vacuum sintering at different temperatures. As a result, better compressibility is observed in the mixes although not all of them present the properties required.

  17. 78 FR 63517 - Control of Ferrite Content in Stainless Steel Weld Metal

    Science.gov (United States)

    2013-10-24

    ... NUCLEAR REGULATORY COMMISSION [NRC-2012-0231] Control of Ferrite Content in Stainless Steel Weld... Ferrite Content in Stainless Steel Weld Metal.'' This guide (Revision 4) describes a method that the NRC staff considers acceptable for controlling ferrite content in stainless steel weld metal. It updates the...

  18. Shaping abilities of two different engine-driven rotary nickel titanium systems or stainless steel balanced-force technique in mandibular molars.

    Science.gov (United States)

    Matwychuk, Michael J; Bowles, Walter R; McClanahan, Scott B; Hodges, Jim S; Pesun, Igor J

    2007-07-01

    The purpose of this study was to compare apical transportation, working-length changes, and instrumentation time by using nickel-titanium (Ni-Ti) rotary file systems (crown-down method) or stainless steel hand files (balanced-force technique) in mesiobuccal canals of extracted mandibular molars. The curvature of each canal was determined and teeth placed into three equivalent groups. Group 1 was instrumented with Sequence (Brasseler USA, Savannah, GA) rotary files, group 2 with Liberator (Miltex Inc, York, PA) rotary files, and group 3 with Flex-R (Union Broach, New York, NY) files. Pre- and postoperative radiographs were superimposed to measure loss of working length and apical transportation as shown by changes in radius of curvature and the long-axis canal angle. Sequence rotary files, Liberator rotary files, and Flex-R hand files had similar effects on apical canal transportation and changes in working length, with no significant differences detected among the 3 groups. Hand instrumentation times were longer than with either Ni-Ti rotary group, whereas the rotary NiTi groups had a higher incidence of fracture.

  19. Temporal sealing material of tritium-contaminated stainless steel

    International Nuclear Information System (INIS)

    Wen Wei; Dan Guiping; Zhang Dong; Qiu Yongmei; Zhang Li

    2010-01-01

    Tritium can be released from the exterior of tritium-contaminated stainless steel by slight stirring while decontaminating and disassembling. In order to avoid secondary tritium contamination to environment and operators, it is necessary to cover with an effective coating to tritium on the exterior of tritium-contaminated stainless steel and fill an effective substance to tritium inside. The results of tritium sealed experiments show that sealing efficiency of neutral silicone rubber is more than 85% for condition of static state and more than 99% for foam concrete condition of dynamic state. Neutral silicone rubber and foam concrete which have finer sealing efficiency can be used as temporal sealed material for the decontamination and disassembly of tritium-contaminated stainless steel. (authors)

  20. Effect of fluoride mouthwash on tensile strength of stainless steel orthodontic archwires

    Science.gov (United States)

    Fatimah, D. I.; Anggani, H. S.; Ismah, N.

    2017-08-01

    Patients with orthodontic treatment are commonly recommended to use a fluoride mouthwash for maintaining their oral hygiene and preventing dental caries. However, fluoride may affect the characteristics of stainless steel orthodontic archwires used during treatment. The effect of fluoride mouthwash on the tensile strength of stainless steel orthodontic archwires is still unknown. The purpose of this study is to know the effect of fluoride mouthwash on the tensile strength of stainless steel orthodontic archwires. Examine the tensile strength of 0.016 inch stainless steel orthodontic archwires after immersion in 0.05%, 100 ml fluoride mouthwash for 30, 60, and 90 min. There is no statistically significant difference in the tensile strength of stainless steel orthodontic archwires after immersed in fluoride mouthwash. The p-values on immersion fluoride mouthwash for 30, 60, and 90 min consecutively are 0.790; 0.742; and 0.085 (p > 0.05). The use of fluoride mouthwash did not have an effect on the tensile strength of stainless Steel orthodontic archwires.