Journal articles: 'Austenitic Stainless Steel-Microstructure'

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Shokohfar, A., S. M. Abbasi, Ali Yazdani, and Behnam Rabiee. "Application of Thermo-Mechanical Process to Achieve Nanostructure in 301 Austenitic Stainless Steels." Defect and Diffusion Forum 312-315 (April 2011): 51–55. http://dx.doi.org/10.4028/www.scientific.net/ddf.312-315.51.

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In this study, cold rolling and annealing are used to refine the austenite grains of 301 austenitic stainless steel. The 301 austenitic stainless steel was cold rolled for 70 and 90% strain and then annealed. Effects of cold rolling factors and temperatures and annealing times on microstructure, hardness and tensile properties have been studied.

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Brytan, Z. "The corrosion resistance of laser surface alloyed stainless steels." Journal of Achievements in Materials and Manufacturing Engineering 2, no. 92 (December 3, 2018): 49–59. http://dx.doi.org/10.5604/01.3001.0012.9662.

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Purpose: of this paper was to examine the corrosion resistance of laser surface alloyed (LSA) stainless steels using electrochemical methods in 1M NaCl solution and 1M H2SO4 solution. The LSA conditions and alloying powder placement strategies on the material's corrosion resistance were evaluated. Design/methodology/approach: In the present work the sintered stainless steels of different microstructures (austenitic, ferritic and duplex) where laser surface alloyed (LSA) with elemental alloying powders (Cr, FeCr, Ni, FeNi) and hard powders (SiC, Si3N4) to obtain a complex steel microstructure of improved properties. Findings: The corrosion resistance of LSA stainless steels is related to process parameters, powder placing strategy, that determines dilution rate of alloying powders and resulting steel microstructure. The duplex stainless steel microstructure formed on the surface layer of austenitic stainless steel during LSA with Cr and FeCr reveal high corrosion resistance in 1M NaCl solution. The beneficial effect on corrosion resistance was also revealed for LSA with Si3N4 for studied steels in both NaCl and H2SO4 solutions. Ferritic stainless steel alloyed with Ni, FeNi result in a complex microstructure, composed of austenite, ferrite, martensite depending on the powder dilution rate, also can improve the corrosion resistance of the LSA layer. Research limitations/implications: The LSA process can be applied for single phase stainless steels as an easy method to improve surface properties, elimination of porosity and densification and corrosion resistance enhancement regarding as sintered material. Practical implications: The LSA of single phase austenitic stainless steel in order to form a duplex microstructure on the surface layers result in reasonably improved corrosion performance. Originality/value: The original LSA process of stainless steels (austenitic, ferritic and duplex) was studied regarding corrosion resistance of the alloyed layer in chloride and sulphate solutions.

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Ravi Kumar, B., J. K. Sahu, and S. K. Das. "Influence of Annealing Process on Recrystallisation Behaviour of a Heavily Cold Rolled AISI 304L Stainless Steel on Ultrafine Grain Formation." Materials Science Forum 715-716 (April 2012): 334–39. http://dx.doi.org/10.4028/www.scientific.net/msf.715-716.334.

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AISI 304L austenitic stainless steel was cold rolled to 90% with and no inter-pass cooling to produced 89% and 43% of deformation induced martensite respectively. The cold rolled specimens were annealed by isothermal and cyclic thermal process. The microstructures of the cold rolled and annealed specimens were studied by the electron microscope. The observed microstructural changes were correlated with the reversion mechanism of martensite to austenite and strain heterogeneity of the microstructure. The results indicated possibility of ultrafine austenite grain formation by cyclic thermal process for austenitic stainless steels those do not readily undergo deformation induced martensite. Keywords: Austenitic stainless steel, Grain refinement, Cyclic thermal process, Ultrafine grain

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Dománková, Mária, Marek Adamech, Jana Petzová, Katarína Bártová, and Peter Pinke. "Microstructure Characteristics of Borated Austenitic Stainless Steel Welds." Research Papers Faculty of Materials Science and Technology Slovak University of Technology 26, no. 43 (September 1, 2018): 45–52. http://dx.doi.org/10.2478/rput-2018-0029.

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Abstract Borated austenitic stainless steel is used in nuclear industry due to the high neutron absorption efficiency. The plasma, laser and electron beam welding experiments were used for the study of the weld joints microstructure. The microstructure changes caused by welding process were observed by light optical microscopy and transmission electron microscopy. The microstructural characterization and microchemical analysis showed significant changes of the phase composition in the weld metal mainly. The austenitic dendrites were surrounded by eutectics, which were the mixture of the M2(C,B) and M23(C,B) borocarbides, δ-ferrite and austenite.

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Al-Fadhalah, Khaled J., Yousif Al-Attal, and Muhammad A. Rafeeq. "Microstructure Refinement of 301 Stainless Steel via Thermomechanical Processing." Metals 12, no. 10 (October 10, 2022): 1690. http://dx.doi.org/10.3390/met12101690.

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The current study applied thermomechanical processing (TMP) on 301 austenitic stainless steel to produce an ultrafine-grained austenitic structure, examining the dual effects of deformation at subzero temperature and TMP cycles on the strain-induced α′-martensitic transformation and austenite reversion occurring upon subsequent annealing. Three TMP schemes were adopted: (1) one cycle using a strain of 0.30, (2) two cycles using a strain of 0.20, and (3) three cycles using a strain of 0.15. Each cycle consisted of tensile deformation at −50 °C followed by annealing at 850 °C for 5 min. Compared to other schemes, the use of three cycles of the 0.15 strain scheme resulted in a significant formation of the martensitic phase to about 99 vol.%. Consequently, the austenite reversion occurred strongly, providing a mixture of the austenitic structure of reverted ultra-fine grains and retained coarse grains with an average grain size of 1.9 µm. The development of a mixed austenitic structure was found to lower the austenite stability and thus enhance the α′-martensitic transformation upon deformation in subsequent cycles. Moderate growth of high-angle grain boundaries occurred in the austenitic phase for all schemes, reaching a maximum of 64% in cycle 3 of the 0.15 strain scheme. The tensile behavior during subzero deformation was generally characterized by an initial strain hardening by slip (stage I), followed by a remarkable increase in strain hardening rate due to the strain-induced α′-martensitic transformation (stage II). Further straining promoted breakage of the α′-martensite banded lath structure for forming dislocation cell-type martensite, which was marked by a decline in strain hardening rate (stage III). Accordingly, the latter hardening stage had a lesser hardness enhancement of deformed samples with an increasing number of cycles. Nevertheless, the yield strength for samples processed by the 0.15 strain scheme improved from 450 MPa in cycle 1 to 515 MPa in cycle 3.

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Zong, Rui Lei, Bo Zhao, Qing Jiang Wang, Qing Feng Yin, and Dong Jin. "Study on Corrosion Behavior of Simulated Welding Microstructure of Austenitic Stainless Steel." Materials Science Forum 1066 (July 13, 2022): 55–59. http://dx.doi.org/10.4028/p-2y16kq.

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In this paper, the simulated welding structure of austenitic stainless steel is prepared by external heating, and the corrosion resistance of austenitic stainless steel in different areas of heat affected zone (HAZ) is evaluated by means of metallographic structure analysis, electrochemical impedance spectroscopy (EIS) test and equivalent circuit numerical fitting analysis. The result shows that the simulated welding structure of austenitic stainless steel had a growth trend with the increase of heating temperature, but the growth trend is not very obvious. The short thermal process has insufficient driving force for the growth of single-phase austenitic structure. The resulting of product resistance and charge transfer resistance of simulated welding microstructure of austenitic stainless steel is not completely consistent. The simulated welding microstructure of stainless steel shows the tendency of corrosion resistance degradation with the heating temperature increasing, and it has slightly lower when the maximum heating temperature locating at 1000-1100 °C.

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Liu, Xiao, and Jing Long Liang. "Effect of Ce on Microstructure and Mechanical Properties of 21Cr-11Ni Austenitic Stainless Steel." Advanced Materials Research 711 (June 2013): 95–98. http://dx.doi.org/10.4028/www.scientific.net/amr.711.95.

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The effect of Ce on structure and mechanical properties of 21Cr11Ni austenitic stainless steels were studied by metallographic examination, scanning electron microscope (SEM), tensile test. The results show that the proper amount of Ce can refine microstructure of austenitic stainless steel. Fracture is changed from cleavage to ductile fracture by adding Ce to austenitic stainless steel. 21Cr11Ni stainless steel containing 0.05% Ce can improve its high temerature strength, and the strength is increased 21.81% at 1073K respectively comparing with that of 21Cr11Ni stainless steel without Ce.

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Itman Filho, André, Wandercleiton da Silva Cardoso, Leonardo Cabral Gontijo, Rosana Vilarim da Silva, and Luiz Carlos Casteletti. "Austenitic-ferritic stainless steel containing niobium." Rem: Revista Escola de Minas 66, no. 4 (December 2013): 467–71. http://dx.doi.org/10.1590/s0370-44672013000400010.

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The austenitic-ferritic stainless steels present a better combination of mechanical properties and stress corrosion resistance than the ferritic or austenitic ones. The microstructures of these steels depend on the chemical compositions and heat treatments. In these steels, solidification starts at about 1450ºC with the formation of ferrite, austenite at about 1300ºC and sigma phase in the range of 600 to 950ºC.The latter undertakes the corrosion resistance and the toughness of these steels. According to literature, niobium has a great influence in the transformation phase of austenitic-ferritic stainless steels. This study evaluated the effect of niobium in the microstructure, microhardness and charge transfer resistance of one austenitic-ferritic stainless steel. The samples were annealed at 1050ºC and aged at 850ºC to promote formation of the sigma phase. The corrosion testes were carried out in artificial saliva solution. The addition of 0.5% Nb in the steel led to the formation of the Laves phase.This phase, associated with the sigma phase, increases the hardness of the steel, although with a reduction in the values of the charge transfer resistance.

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Silva Leite, Carla Gabriela, Eli Jorge da Cruz Junior, Mattia Lago, Andrea Zambon, Irene Calliari, and Vicente Afonso Ventrella. "Nd: YAG Pulsed Laser Dissimilar Welding of UNS S32750 Duplex with 316L Austenitic Stainless Steel." Materials 12, no. 18 (September 9, 2019): 2906. http://dx.doi.org/10.3390/ma12182906.

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Duplex stainless steels (DSSs), a particular category of stainless steels, are employed in all kinds of industrial applications where excellent corrosion resistance and high strength are necessary. These good properties are provided by their biphasic microstructure, consisting of ferrite and austenite in almost equal volume fractions of phases. In the present work, Nd: YAG pulsed laser dissimilar welding of UNS S32750 super duplex stainless steel (SDSS) with 316L austenitic stainless steel (ASS), with different heat inputs, was investigated. The results showed that the fusion zone microstructure observed consisted of a ferrite matrix with grain boundary austenite (GBA), Widmanstätten austenite (WA) and intragranular austenite (IA), with the same proportion of ferrite and austenite phases. Changes in the heat input (between 45, 90 and 120 J/mm) did not significantly affect the ferrite/austenite phase balance and the microhardness in the fusion zone.

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Ramesh, Aditya, Vishal Kumar, Anuj, and Pradeep Khanna. "Weldability of duplex stainless steels- A review." E3S Web of Conferences 309 (2021): 01076. http://dx.doi.org/10.1051/e3sconf/202130901076.

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Duplex stainless steel finds widespread use in various sectors of manufacturing and related fields. It has many advantages due to its distinctive structural combination of austenite and ferrite grains. It is the need of the current generation due to its better corrosive resistance over high production austenitic stainless steels. This paper reviews the weldability of duplex stainless steels, mentions the reason behind the need for duplex stainless steels and describes how it came into existence. The transformations in the heat-affected zones during the welding of duplex stainless steels have also been covered in this paper. The formation, microstructure and changes in high temperature and low temperature heat-affected zones have been reviewed in extensive detail. The effects of cooling rate on austenite formation has been briefly discussed. A comparison of weldability between austenitic and duplex stainless steel is also given. Finally, the paper reviews the applications of the various grades of duplex stainless steel in a variety of industries like chemical, paper and power generation and discusses the future scope of duplex stainless steel in various industrial sectors.

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Han, Fei, Gao Yong Lin, Qian Li, Rui Fen Long, Da Shu Peng, and Qing Zhou. "Influence of Different Deformation on Microstructure and Properties of 304 Austenitic Stainless Steel." Advanced Materials Research 500 (April 2012): 690–95. http://dx.doi.org/10.4028/www.scientific.net/amr.500.690.

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In this paper, a kind of 304 austenitic stainless steel sheets has been investigated, and systemic tests were conducted to study the law and mechanics of work hardening of 304 austenitic stainless steel. The results of microstructure analyzing of 304 austenitic stainless steels showed that when it was deformed by means of tensile testing at room temperature, obvious work hardening was caused by the changes of structure during the deformation. The strain-induced α-martensite, ε-martensite and deformation twins enhanced flow stress obviously, which is the main reason for the strong work hardening in FCC metals and alloys with low stacking fault energy as 304 austenitic stainless steel.

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12

Rivai, Abu Khalid, Nanda Shabrina, Bambang Sugeng, and Sulistioso Giat Sukaryo. "Microstructure Investigations of Phase Transformation in Cold Working AISI 316L Austenitic Stainless Steel." Journal of Physics: Conference Series 2243, no. 1 (June 1, 2022): 012063. http://dx.doi.org/10.1088/1742-6596/2243/1/012063.

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Abstract Development of high temperature and corrosion-resistant materials is one of the key issues for the deployment of advanced nuclear reactors and also to accommodate the problem that occurred in the conventional reactor as the lesson-learned from Fukushima Daiichi nuclear reactor power plant accident. One of the high performance materials for that purpose is austenitic stainless steel such as AISI 316L that widely used for power plant. In this study we investigate the characteristics of AISI 316L austenitic phase transformation if cold working is applied. In general, during the cold working process the mechanical characteristic and the phase of the austenitic steel will change. It is expected that the characteristic of AISI 316L austenitic steel will be improved by optimum cold working mechanism. Cold working of AISI 316L austenitic steel at various percentage reduction of 5%, 15%, 25% and 38% have been done. Afterward, the sample was characterized using X-Ray Diffraction and Optical Microscope to analyze the microstructure characteristics and phase transformation. The results showed that the phase transformation in AISI 316L austenitic steel occurred from austenite – gamma (FCC: Face-Centered Cubic lattice) to martensite – alpha prime (BCC: Body Centered Cubic lattice). The percentage of martensite phase was increasingly growth related to the increasing of the percentage of cold working value i.e. 8.3%, 21.6%, 29.6% and 37.1%, respectively. The hardness of AISI 316L austenitic steel increased with the increasing of the cold working percentage. AISI 316L double phases which covers of austenite-martensite intermix phase structure with higher hardness mechanical properties has been successfully developed.

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Abass, M. H., M. S. Alali, W. S. Abbas, and A. A. Shehab. "Study of solidification behaviour and mechanical properties of arc stud welded AISI 316L stainless steel." Journal of Achievements in Materials and Manufacturing Engineering 1, no. 97 (November 3, 2019): 5–14. http://dx.doi.org/10.5604/01.3001.0013.7944.

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Purpose: This paper aims to investigate the impact of arc stud welding (ASW) process parameters on the microstructure and mechanical properties of AISI 316L stainless steel stud/plate joint. Design/methodology/approach: The weld performed using ASW machine. The influence of welding current and time on solidification mode and microstructure of the fusion zone (FZ) was investigated using optical microscope and scanning electron microscope (SEM). Microhardness and torque strength tests were utilised to evaluate the mechanical properties of the welding joint. Findings: The results showed that different solidification modes and microstructure were developed in the FZ. At 400 and 600 A welding currents with 0.2 s welding time, FZ microstructure characterised with single phase austenite or austenite as a primary phase. While with 800 A and 0.2 s, the microstructure consisted of ferrite as a primary phase. Highest hardness and maximum torque strength were recorded with 800 A. Solidification cracking was detected in the FZ at fully austenitic microstructure region. Research limitations/implications: The main challenge in this work was how to avoid the arc blow phenomenon, which is necessary to generate above 300 A. The formation of arc blow can affect negatively on mechanical and metallurgical properties of the weld. Practical implications: ASW of austenitic stainless steel are used in multiple industrial sectors such as heat exchangers, boilers, furnace, exhaust of nuclear power plant. Thus, controlling of solidification modes plays an important role in enhancing weld properties. Originality/value: Study the influence of welding current and time of ASW process on solidification modes, microstructure and mechanical properties of AISI 316 austenitic stainless steel stud/plate joint.

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Wang, Min, and Hong Zhen Guo. "Influence of Deformation Heat Treatment on the Ultra-Fine Structure of Austenitic Stainless Steel." Materials Science Forum 551-552 (July 2007): 421–25. http://dx.doi.org/10.4028/www.scientific.net/msf.551-552.421.

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According to accommodate-state and big bulk 18-8 type austenitic stainless steel has the weakness of coarse-grained and low strength. Optical microscopy，electron microscopy and X-ray diffraction were used to analyze microstructure and grain size of austenitic stainless steel specimens after deformation heat treatment. The paper investigates the influence of recrystallization annealing on the ultra-fine structure of cold deformation austenitic stainless steel. The results show that austenitic stainless steel can produce deformation-induced martensite by cold rolling deformation， and that the content of martensite increases with deformation degree. During the annealing, ultra-fine grains can be obtained by the reversal transformation-induced martensite(M′→ γ ). After severe cold deformation, inside austenitic grains imported austenitic-martensite(γ /M) phase boundaries shall serve to add a great deal of forming nucleus location for recrystallization, to enhance forming nucleus ratio and refine grain. 1Cr18Ni9Ti austenitic stainless steel by severe cold deformation and recrystallization annealing can acquire ultra-fine grains.

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Surasno, Surasno. "Effect of Heat Input on Dilution, Hardness, and Microstructure in DMW Stainless Steel and Carbon Steel." Key Engineering Materials 884 (May 2021): 437–43. http://dx.doi.org/10.4028/www.scientific.net/kem.884.437.

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The success of Dissimilar Metal Welding (DMW) occurred in optimal Heat-input (HI) parameters. The quality of welding joints was affected by dilution, hardness value, and intermetallic microstructure. DMW quality research was carried out on stainless steel SA SS312-TP304 and SA 53GrB carbon steel using the GTAW (Gas Tungsten Arc Welding) process with Heat-input of 1866.6 to 2362.2 J/mm. Visual observation on weld joints was not found weld defects. The optimal dilution area in the Schaeffler Diagram was obtained 35.35% austenitic area and without ferrite content. The lowest hardness value on carbon steel was 145 HV. The highest hardness value of 197 HV occurred in filler-metal dilution on carbon steel, so the difference in the value of hardness was high. The hardness value on stainless steel was 184 HV and in filler-metal stainless steel dilution was 172– 90 HV, so the difference in hardness value was low. Microstructure filler-metal dilution on stainless steel was austenite-dendritic, filler-metal dilution on carbon steel was fine-grained dendritic, and on allweld metal coarse-grained dendritic metal. HAZ stainless steel austenite microstructure and ferrite-pearlite carbon steel with an indication of a ferrite net. Observation of dilution, hardness value, and microstructure in DMW did not have a significant effect. This welded joint could be used as a reference in the DMW fabrication process for stainless steel and carbon steel pipe connections.

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Zhang, Hui, Yanfeng Liu, Xian Zhai, and Wenkai Xiao. "Effects of High Temperature Aging Treatment on the Microstructure and Impact Toughness of Z2CND18-12N Austenitic Stainless Steel." Metals 10, no. 12 (December 18, 2020): 1691. http://dx.doi.org/10.3390/met10121691.

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During the casting cooling process or the forging process, austenitic stainless steel will remain at around 800 °C for some time. During this period, precipitate particle behaviors in austenitic stainless steel (containing ferrite) will cause a reduction in ductility, which can lead to material cracking. In this study, the effects of aging at 800 °C on the microstructure, impact toughness and microhardness of Z2CND18-12N austenitic stainless steel were systematically investigated. The precipitation processes of the χ and σ phases were characterized by color metallography and back scattered electron (BSE) signals. The toughness was investigated by the Charpy impact test. After the aging treatment, the χ and σ phases precipitated successively in the ferrite, and as the aging duration increased, the χ-phase dissolved and the σ-phase precipitated along the austenite grain boundaries. These all lead to a decrease in toughness and an increase in microhardness. Finally, the relationship between fracture morphology and aging time is discussed herein, and a crack mechanism is given.

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Degallaix, Suzanne, Florence Jaupitre, Djimedo Kondo, Philippe Quaegebeur, and Pierre Forget. "Identification and Modelling of the Behaviour of a Duplex Stainless Steel by Methods of Scale Changing." Materials Science Forum 482 (April 2005): 231–34. http://dx.doi.org/10.4028/www.scientific.net/msf.482.231.

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In order to model the mechanical behaviour of an austenitic-ferritic duplex stainless steel thanks to "composite" micromechanical non-linear models, its microstructure was analysed and the mechanical behaviour of each phase was characterised. The microstructural morphology of this steel was studied by selective dissolution of the austenitic phase. The microstructure consists of unconnected austenite islands dispersed in a ferritic matrix. Nano-indentation tests were carried out on each phase. These tests allowed to obtain the hardness and the Young modulus of each phase. A non-linear homogenization approach (secant and incremental formulations) was implemented and the results were compared to the monotonous macroscopic tensile tests carried out at constant strain rate. It allowed us to evaluate the relevance of the non-linear homogeneization models for the description of the elasto-plastic behaviour of the studied duplex stainless steel.

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Borgioli, Francesca, Emanuele Galvanetto, and Tiberio Bacci. "Surface Modification of a Nickel-Free Austenitic Stainless Steel by Low-Temperature Nitriding." Metals 11, no. 11 (November 17, 2021): 1845. http://dx.doi.org/10.3390/met11111845.

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Low-temperature nitriding allows to improve surface hardening of austenitic stainless steels, maintaining or even increasing their corrosion resistance. The treatment conditions to be used in order to avoid the precipitation of large amounts of nitrides are strictly related to alloy composition. When nickel is substituted by manganese as an austenite forming element, the production of nitride-free modified surface layers becomes a challenge, since manganese is a nitride forming element while nickel is not. In this study, the effects of nitriding conditions on the characteristics of the modified surface layers obtained on an austenitic stainless steel having a high manganese content and a negligible nickel one, a so-called nickel-free austenitic stainless steel, were investigated. Microstructure, phase composition, surface microhardness, and corrosion behavior in 5% NaCl were evaluated. The obtained results suggest that the precipitation of a large volume fraction of nitrides can be avoided using treatment temperatures lower than those usually employed for nickel-containing austenitic stainless steels. Nitriding at 360 and 380 °C for duration up to 5 h allows to produce modified surface layers, consisting mainly of the so-called expanded austenite or γN, which increase surface hardness in comparison with the untreated steel. Using selected conditions, corrosion resistance can also be significantly improved.

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Lin, Shao Pin, Ge Ping Yu, J. Y. Huang, H. J. Chen, R. C. Kuo, E. Wen Huang, and Jia Hong Huang. "The Effect of Shielded Metal Arc and Gas Tungsten Arc Welding Methods on 308L Stainless Steel Weldments." Materials Science Forum 783-786 (May 2014): 2753–57. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.2753.

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Shielded metal arc (SMA) and gas tungsten arc (GTA) weldments were investigated to study the welding effects on the mechanical behavior of 308L austenitic stainless steel weldments, respectively. Both SMA and GTA weldments showed dendritic microstructure. The observed austenitic stainless steel welds solidified to give primary ferrite and secondary austenite as the ferritic-austenitic solidification mode (FA-mode) solidification. However, the lower heat input with larger Cr-versus-Ni ratio in SMA weld process led to lathy ferrite morphology and more residual ferrite in the SMA welds, while vermicular ferrite morphology was shown in GTA weldments. The yield strength of the welds significantly increased with decreasing elongation, which was mainly due to the dual phase strengthening effect after rapid solidification during welding

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Wen, Ming, Wei Li, and Xiao Ming Cao. "Research on the Mechanical Properties for Medical Stainless Steel." Advanced Materials Research 383-390 (November 2011): 3976–79. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.3976.

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The stainless steel is more and more applications to the medical field; the most is the austenitic stainless steel. In this paper, 00Cr18Ni14Mo3 mechanical properties of austenitic stainless steel screw, compared to the solution of the former and the sample microstructure after solution treatment, energy spectrum and the torque angle reverse faults, compared to solution treatment found that mechanical properties of the samples after meet the standard can be applied to practice.

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Shen, Lie, Liang Wang, Jiu Jun Xu, and Ying Chun Shan. "Effect of Pre-Shot Peening on Plasma Nitriding Kinetics of Austenitic Stainless Steel." Advanced Materials Research 634-638 (January 2013): 2955–59. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.2955.

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The fine grains and strain-induced martensite were fabricated in the surface layer of AISI 304 austenitic stainless steel by shot peening treatment. The shot peening effects on the microstructure evolution and nitrogen diffusion kinetics in the plasma nitriding process were investigated by optical microscopy and X-ray diffraction. The results indicated that when nitriding treatments carried out at 450°C for times ranging from 0 to 36h, the strain-induced martensite transformed to supersaturated nitrogen solid solution (expanded austenite), and slip bands and grain boundaries induced by shot peening in the surface layer lowered the activation energy for nitrogen diffusion and evidently enhanced the nitriding efficiency of austenitic stainless steel.

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Fourlaris, G., and T. Gladman. "A TEM microscopical investigation of the magnetic domain structure of a metastable austenitic stainless steel." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 696–97. http://dx.doi.org/10.1017/s0424820100171213.

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Stainless steels have widespread applications due to their good corrosion resistance, but for certain types of large naval constructions, other requirements are imposed such as high strength and toughness , and modified magnetic characteristics.The magnetic characteristics of a 302 type metastable austenitic stainless steel has been assessed after various cold rolling treatments designed to increase strength by strain inducement of martensite. A grade 817M40 low alloy medium carbon steel was used as a reference material.The metastable austenitic stainless steel after solution treatment possesses a fully austenitic microstructure. However its tensile strength , in the solution treated condition , is low.Cold rolling results in the strain induced transformation to α’- martensite in austenitic matrix and enhances the tensile strength. However , α’-martensite is ferromagnetic , and its introduction to an otherwise fully paramagnetic matrix alters the magnetic response of the material. An example of the mixed martensitic-retained austenitic microstructure obtained after the cold rolling experiment is provided in the SEM micrograph of Figure 1.

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Mustofa, Salim, M. Dani, Parikin Parikin, Toto Sudiro, Bambang Hermanto, D. R. Adhika, Andon Insani, Syahbuddin Syahbuddin, Takanori Hino, and C. A. Huang. "HRPD and TEM Study of P/M 58Fe17Cr25Ni Austenitic Stainless Steel Synthesized by Spark Plasma Sintering." Acta Metallurgica Slovaca 28, no. 4 (December 13, 2022): 224–29. http://dx.doi.org/10.36547/ams.28.4.1548.

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58Fe17Cr25Ni austenite stainless steel has been fabricated using metal powder through sintering with a spark plasma at temperatures of 900 and 950°C for 5 minutes. High purity Fe, Ni and Cr powders were used as materials for this steel. Before sintering, the powder was mixed in a milling equipment which was processed for 5 hours, then it is formed into a coin by pressing it under a load of 25 tons. High resolution powder neutron diffractometer was used for identifying the crystal structure in the 58Fe17Cr25Ni austenitic stainless steel. The sintering process at temperatures of 900C and 950°C generally forms microstructure having matrix of equiaxed austenite grains, with a crystal structure of face-centered cubic which included in the Fm3m space group. Some particles with high Cr content, a'-Cr, are distributed in all austenite grains. The austenite grains seen in the 58Fe17Cr25Niaustenitic stainless steel sintered at 900°C are twin grains. Dislocations, slip planes and bands are also existed in those grains. These defects are expected to decrease with increasing sintering temperatures up to 950° C. This change was followed by the appearance of air bubbles and sub-grains as the dominant sub-structures in the 58Fe17Cr25Ni austenitic stainless steel sintered at 950°C.

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Krawczynska, Agnieszka T., Małgorzata Lewandowska, and Krzysztof Jan Kurzydlowski. "Recrystallization in Nanostructured Austenitic Stainless Steel." Materials Science Forum 584-586 (June 2008): 966–70. http://dx.doi.org/10.4028/www.scientific.net/msf.584-586.966.

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Recrystallization and grain growth were studied in an austenitic stainless steel 316LVM processed by hydrostatic extrusion (HE) to a total true strain of 2. HE processing produces in this material the microstructure which consists of nanoscale twins on average 19 nm in width and 168 nm in length. The samples after HE were annealed at various temperatures for 1 hour. The structural changes were investigated using TEM. The heat induced changes in nanotwinned austenitic steel are significantly different when compared to the ones in a conventionally deformed material. Microstructural changes take place at lower annealing temperature. Annealing at 600°C brings about a partial a nanostructure reorganization into nanograin of average size 54 nm. An uniform microstructure with nanograins of 68 nm in equivalent diameter was obtained after annealing at 700°C whereas conventional 316LVM steel fully recrystallizes after annealing at 900°C for 1h. Annealing at higher temperatures results in grain growth.

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Khdir, Younis K., Salim A. Kako, and Ramadhan H. Gardi. "Study of Welding Dissimilar Metals – Low-carbon Steel AISI 1018 and Austenitic Stainless Steel AISI 304." Polytechnic Journal 10, no. 1 (June 30, 2020): 1–5. http://dx.doi.org/10.25156/ptj.v10n1y2020.pp1-5.

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The aim of this study is to investigate the influence of different heat inputs on mechanical properties and microstructure of dissimilar electrical arc welded austenitic stainless steel AISI 304 and low-carbon steel (CS) joints. The mechanical properties of welded austenitic stainless steel type AISI 304 and low-CS are studied. Five different heat inputs 0.5, 0.9, 1.41, 2, and 2.5 KJ/min were applied to investigate the microstructure of the welded zone and mechanical properties. The results showed that the efficiency of the joints and tensile strength increased with increasing heat inputs, while excess heat input reduces the efficiency. Furthermore, changes in microstructure with excess heat input cause failure at the heat-affected zone.

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Oktadinata, Herry, Toto Triantoro, Aji Gumilar, and Unggul Ramadani Jatmiko. "Microstructure and Hardness Properties of AISI 321 Stainless Steel Welded Joints with Different Filler Metal." Key Engineering Materials 951 (August 7, 2023): 3–9. http://dx.doi.org/10.4028/p-gou7ql.

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Austenitic stainless steel is susceptible to sensitization when exposed to high temperatures. During welding operations, they tend to form chromium depletion zones and thus become susceptible to intergranular corrosion. The microstructure and hardness properties of AISI 321 austenitic stainless steel welds have been studied in this work. The phenomenon of sensitization of AISI 321 stainless steel during GTAW has also been investigated. This experiment observed three welded samples using different filler metals, ER316, ER308, and ER347. Weld sample analysis was studied using an optical microscope and a microhardness tester. The results demonstrated that the type of filler metal significantly affected changes in the microstructure and hardness of the weld joint.

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Wen, Ming, Wei Li, and Xiao Ming Cao. "Research on the Mechanical Properties for Medical Stainless Steel." Advanced Materials Research 433-440 (January 2012): 100–103. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.100.

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The stainless steels is more and more applications to the medical field, the most is the austenitic stainless steel. In this paper, 00Cr18Ni14Mo3 mechanical properties of austenitic stainless steel screw, compared to the solution of the former and the sample microstructure after solution treatment, energy spectrum and the torque angle reverse faults, compared to solution treatment found that mechanical properties of the samples after meet the standard can be applied to practice

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Wang, Shao Gang, Yan Li, and Wei Guo Zhai. "Microstructure and Corrosion Resistance of Dissimilar Welded Joints between Duplex Stainless Steel and Austenitic Stainless Steel." Advanced Materials Research 570 (September 2012): 43–51. http://dx.doi.org/10.4028/www.scientific.net/amr.570.43.

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The dissimilar metals components of duplex stainless steels are more and more used in engineering fields recently. But the welding of dissimilar metals is more a challenge than that of similar metals. The joints of dissimilar metals between 2205 duplex stainless steel and 304 austenitic stainless steel were produced by tungsten inert gas arc welding (GTAW) with welding wire ER2209 and ER309, respectively. The microstructural characterization of welded joints is systematically analyzed by using optical microscope and X-ray diffractometer. The pitting corrosion resistance of the joints is evaluated by electrochemical test. Results show that the microstructure of joint consists of austenite and ferrite, and no detrimental phases precipitate in the weldment. The biphase ratio of austenite (γ) / ferrite (α) is adequate both in weld metal and heat-affected zone (HAZ), which is advantageous to the performance of welded joints. The weld metals have relatively lower pitting corrosion resistance compared with the 2205 base metal, and the pitting corrosion resistance of the joint produced with ER2209 is better than that of the joint with ER309 in chloride solution.

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Ziewiec, A., E. Tasak, M. Witkowska, and K. Ziewiec. "Microstructure and Properties of Welds of Semi-Austenitic Precipitation Hardening Stainlees Steel after Heat Treatment." Archives of Metallurgy and Materials 58, no. 2 (June 1, 2013): 613–17. http://dx.doi.org/10.2478/amm-2013-0046.

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This paper presents the studies of the microstructure and properties of the welded joints made of 15-7Mo precipitation hardened semi-austenitic stainless steel welded by Tungsten Inert Gas. Microstructural changes in the heat treated welded joints was assessed. It was found that the joints of 15-7Mo steel in as welded state contain martensite, austenite and δ-ferrite. Scanning electron microscope study of the joints was carried out. The sub-zero and destabilization heat treatment were found to decrease or completely eliminate the austenite in the microstructure and increase hardness of the welded joint.

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30

Ryś, Janusz, and Małgorzata Witkowska. "Microstructure and Deformation Behavior of Cold-Rolled Super-Duplex Stainless Steel." Solid State Phenomena 163 (June 2010): 151–56. http://dx.doi.org/10.4028/www.scientific.net/ssp.163.151.

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The present examination is a part of project concerning a deformation behavior of duplex type ferritic-austenitic stainless steels. The investigations included the analysis of ferrite and austenite microstructures formed in cold-rolled sheet of super-duplex stainless steel, major deformation mechanisms operating in both constituent phases and changes in morphology of two-phase structure after the thermo-mechanical treatment and subsequent cold-rolling. Duplex type stainless steels develop the band-like ferrite-austenite morphology in the course of hot- and cold-rolling. This specific two-phase structure creates different conditions for plastic deformation in comparison to single phase steels. The interaction of both phases upon deformation exerts fairly significant influence on structure and texture formation in both constituent phases and in consequence affects the material properties and its behavior upon further processing.

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31

Gigović-Gekić, Almaida, Hasan Avdušinović, Amna Hodžić, and Ermina Mandžuka. "Effect of Temperature and Time on Decomposition of δ-ferrite in Austenitic Stainless Steel." Materials and Geoenvironment 67, no. 2 (July 27, 2020): 65–71. http://dx.doi.org/10.2478/rmzmag-2020-0007.

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AbstractMicrostructure of austenitic stainless steel is primarily monophasic, i.e. austenitic. However, precipitation of the δ-ferrite in the austenite matrix is possible depending on the chemical composition of steel. δ-Ferrite is stable on room temperature but it transforms into σ-phase, carbides and austenite during heat treatment. In this work, the results of analysis of influence of temperature and time on decomposition of δ-ferrite are presented. Magnetic induction method, microstructure and hardness analyses were used for testing the degree of decomposition of the δ-ferrite. Analysis of results showed that increase in temperature and time increases the degree of decomposition of δ-ferrite.

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32

Zbigniew, Brytan, Mirołsaw Bonek, Leszek Adam Dobrzański, Daniele Ugues, and Marco Actis Grande. "The Laser Surface Remelting of Austenitic Stainless Steel." Materials Science Forum 654-656 (June 2010): 2511–14. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2511.

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The laser surface remelting (LSR) process was successfully applied to restore localized corrosion resistance in sensitized stainless steel and also as a useful method to improve passivity of some martensitic stainless steels. The LSR process can be successfully applied to repair cracks and defects at the surface of highly thermo-mechanically loaded parts of stainless steel. The purpose of presented study was to evaluate the microstructure and properties of laser remelted surface of stainless steels. The wrought austenitic stainless steel and sintered in vacuum 316L type were studied. The laser treatment was performed with the use of high power diode laser (HPDL) and the influence of beam power of 0.7-2.1kW on the properties of the surface layer was evaluated. The geometrical characteristics and x-ray analysis of weld bead were studied as well as microhardness, surface roughness and corrosion resistance were measured. The increase of laser beam power of LSR resulted in the increase of hardness of sintered stainless steel due to the reduction of porosity and formation of fine dendritic and cellular-dendritic microstructure. The corrosion resistance of remelted surface increased for sintered materials, when remelted at 2.1kW. The wrought stainless steel revealed impairment of pitting corrosion when remelted at lower beam power rate.

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Xu, Qinhua, Jianxin Zhu, Yong Zong, Lihua Liu, Xiaoyong Zhu, Fuen Zhang, and Baifeng Luan. "Effect of drawing and annealing on the microstructure and mechanical properties of 304 austenitic stainless steel wire." Materials Research Express 8, no. 12 (December 1, 2021): 126530. http://dx.doi.org/10.1088/2053-1591/ac44d6.

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Abstract Plastic deformation at room temperature, and the proceeding heat treatments, are important processes for optimizing the microstructure and mechanical properties of austenitic stainless steel. The microstructure and mechanical properties of cold-drawn 304 austenitic stainless steel wire were investigated after annealing at 700 °C and 800 °C, with different times (20, 40 and 60 min) and drawing strain (0.4, 1.0 and 1.5). Electron backscattered diffraction (EBSD) techniques, transmission electron microscope (TEM) analysis, differential scanning calorimeter (DSC) and tensile tests were performed in order to study the microstructure evolution and mechanical properties during different annealing processes for the 304 austenitic stainless steel wire. The results showed that the quantity of α′ martensite and dislocations increased with an increase in the strain, which means that, while the ultimate tensile strength of the cold-drawn wires elevated, the elongation reduced. The mechanical properties of stainless steel wires also varied with the evolution of martensite transformation characteristics, density of stacking fault, dislocation and twin, as well as the recrystallization degree under various annealing conditions. The recrystallization temperature of steel wire was mainly determined by the magnitude of the strain, while the martensite reversal temperature was determined by the stacking fault energy and the deformation value. The temperature of recrystallization and martensite reverse in steel wire decreased with the increment of the strain. The balance of tensile strength and elongation of steel wire can be obtained by adopting the proper annealing process combined with cold-drawing deformation. In this paper, we showed that a good combination of strength and elongation in 304 austenitic stainless steel can be obtained with a strain of 1.5 annealed at 800 °C for 20 min.

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Herrera, Clara, Angelo Fernando Padilha, and R. L. Plaut. "Microstructure Evolution during Annealing Treatment of Austenitic Stainless Steels." Materials Science Forum 715-716 (April 2012): 913. http://dx.doi.org/10.4028/www.scientific.net/msf.715-716.913.

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Austenitic stainless steels of the AISI 304 and 316 grades, amongst over other hundred compositions of stainless steels available in the market, are the most frequently used ones worldwide. They are selected for numerous applications due to their favorable combination of characteristics such as low price, moderate to good corrosion resistance, excellent ductility and toughness along with good weldability. Their major limitation is in the yield strength, which is relatively low (about 200 MPa), in the annealed condition. Through cold working, this value can be easily multiplied by a factor of up to six, however ductility drops. The cold worked sub-structure of the austenitic stainless steels is formed by a planar array of dislocations and strain induced martensites, α (BCC) and ε (HCP). The microstructure evolution of austenitic stainless steels, AISI 304L and 316L, during cold rolling and subsequent annealing was studied (maximum thickness reduction - 90%). Samples were initially solution annealed at 1100°C for one hour with subsequent water quenched. Following, they have been cold rolled at room temperature, with cold reductions varying between 10 and 90%. After rolling, samples with approximately 90% thickness reduction have been submitted to annealing treatments in order to study martensite reversion, recovery and recrystallization. Annealing treatments have been performed between 200 and 900°C, with 100°C interval for one hour. The resulting microstructures were investigated by optical microscopy, scanning electron microscopy (with EBSD), magnetic measurements and hardness evaluation. As received (hot rolled) austenitic stainless steel sheet presented recrystallized equiaxial grains with austenite and islands of delta ferrite, in larger quantities mainly in the centre of the sheet. The solution annealing at 1100°C for one hour eliminated delta ferrite. During rolling, the austenite partially transforms into α martensite. The 50% αmartensite reversion temperature is close to 550°C for both steels. This temperature is practically independent of the amount of αmartensite present in the steel. The 50% recrystallization temperature of the 304L steel is lower than that of the 316L steel, about 700 and 800°C, respectively. The 316L steel shows a higher recrystallization resistance, due to its higher SFE and lower storage deformation energy than the 304L steel. Recrystallization temperature is about 150°C higher that the αmartensite reversion temperature. The percentage of αmartensite has a strong influence on the recrystallized grain size, the higher the percentage of this phase the smaller will be the grain size.

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35

Jiang, J. C., and E. I. Meletis. "Microstructure of Plasma-Nitrided 316 Austenitic Stainless Steel." Microscopy and Microanalysis 6, S2 (August 2000): 450–51. http://dx.doi.org/10.1017/s1431927600034747.

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Austenitic stainless steels plasma-nitrided at low temperature can have a tremendously improved surface hardness without affecting their excellent corrosion resistance. The surface layer of these nitrided materials was considered to be composed of an uncharacterized, so called “S-phase”. During the past decade, several research groups have studied “S” phase using X-ray diffraction and transmission electron microscopy (TEM), but its microstructure is not yet well understood and is still a topic of debate. In this paper, we characterize the microstructure of 316 stainless steel nitrided by intensified plasma-assisted processing (IPAP) using cross-sectional TEM.Samples of 316 austenitic stainless steel were nitrided for 1 hour by IPAP at a temperature of ∼ 400 °C. Plasma-nitrided samples were cross-sectioned and glued face-to-face by joining the nitrided surface. Crosssectional specimens for TEM observations were prepared by mechanical grinding, polishing and dimpling followed by Ar+ milling. TEM studies were carried out in a newly installed JEOL JEM 2010 electron microscope in the Materials Characterization Facility at the Louisiana State University.

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36

Shvab, Ruslan, Eduard Hryha, Petro Shykula, Eva Dudrová, Ola Bergman, and Sven Bengtsson. "Microstructure of High Cr-Alloyed Sintered Steel – Prediction and Analysis." Materials Science Forum 782 (April 2014): 473–79. http://dx.doi.org/10.4028/www.scientific.net/msf.782.473.

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Study of microstructure of high Cr-alloyed sintered austenitic stainless steel was performed in few stages XPS analysis of powder surface, theoretical prediction of microstructure by Thermo-Calc and JMatPro software and metallographic observation of sintered material. XPS analysis showed presence of thin iron oxide layer on the surface of powder particles and oxide islands formed by Si, Mn and Cr. Theoretical prediction made by Thermo-Calc and JMatPro calculations showed presence of austenite with chromium carbides and carbonitrides in equilibrium state. Both predictions are in good agreement. Metallographic observation of sintered material showed that microstructure contains small austenitic grains with size of 3-5 μm with fine carbides (1-2 μm) and carbonitrides distributed mostly on grain boundaries. Metallographic study of material confirmed theoretical predictions.

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37

Pereira, Juan Carlos, David Aguilar, Iosu Tellería, Raul Gómez, and María San Sebastian. "Semi-Continuous Functionally Graded Material Austenitic to Super Duplex Stainless Steel Obtained by Laser-Based Directed Energy Deposition." Journal of Manufacturing and Materials Processing 7, no. 4 (August 12, 2023): 150. http://dx.doi.org/10.3390/jmmp7040150.

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In this work, a semi-continuous functionally graded material (FGM) between an austenitic and a super duplex stainless steel was obtained. These materials are of great interest for the chemical, offshore, and oil and gas sectors since the austenitic stainless steel type 316L is common (and not so expensive) and super duplex stainless steels have better mechanical and corrosion resistance but are more expensive and complex in their microstructural phases formation and the obtention of the balance between their main phases. Using directed energy deposition, it was possible to efficiently combine two powders of different chemical compositions by automated mixing prior to their delivery into the nozzle, coaxially to the laser beam for melting. A dense material via additive manufacturing was obtained, with minimum defectology and with a semi-continuous and controlled chemical compositional gradient in the manufactured part. The evolution of ferrite formation has been verified and the phase fraction measured. The resulting microstructure, austenite/ferrite ratio, and hardness variations were evaluated, starting from 100% austenitic stainless-steel composition and with variants of 5% in wt.% until achieving 100% of super duplex steel at the end of the part. Finally, the correlation between the increase in hardness of the FGM with the increase in the ferrite phase area fraction was verified.

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38

Pańcikiewicz, Krzysztof, Aleksandra Świerczyńska, Paulina Hućko, and Marek Tumidajewicz. "Laser Dissimilar Welding of AISI 430F and AISI 304 Stainless Steels." Materials 13, no. 20 (October 13, 2020): 4540. http://dx.doi.org/10.3390/ma13204540.

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A dissimilar autogenous laser welded joint of AISI 430F (X12CrMoS17) martensitic stainless steel and AISI 304 (X5CrNi18-10) austenitic stainless steel was manufactured. The welded joint was examined by non-destructive visual testing and destructive testing by macro- and microscopic examination and hardness measurements. With reference to the ISO 13919-1 standard the welded joint was characterized by C level, due to the gas pores detected. Microscopic observations of AISI 430F steel revealed a mixture of ferrite and carbides with many type II sulfide inclusions. Detailed analysis showed that they were Cr-rich manganese sulfides. AISI 304 steel was characterized by the expected austenitic microstructure with banded δ-ferrite. Martensitic microstructure with fine, globular sulfide inclusions was observed in the weld metal. The hardness in the heat-affected zone was increased in the martensitic steel in relation to the base metal and decreased in the austenitic steel. The hardness range in the weld metal, caused by chemical inhomogeneity, was 184–416 HV0.3.

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Monteiro, Waldemar Alfredo, Silvio Andre Lima Pereira, and Jan Vatavuk. "Nitriding Process Characterization of Cold Worked AISI 304 and 316 Austenitic Stainless Steels." Journal of Metallurgy 2017 (January 18, 2017): 1–7. http://dx.doi.org/10.1155/2017/1052706.

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The nitriding behavior of austenitic stainless steels (AISI 304 and 316) was studied by different cold work degree (0% (after heat treated), 10%, 20%, 30%, and 40%) before nitride processing. The microstructure, layer thickness, hardness, and chemical microcomposition were evaluated employing optical microscopy, Vickers hardness, and scanning electron microscopy techniques (WDS microanalysis). The initial cold work (previous plastic deformations) in both AISI 304 and 306 austenitic stainless steels does not show special influence in all applied nitriding kinetics (in layer thicknesses). The nitriding processes have formed two layers, one external layer formed by expanded austenite with high nitrogen content, followed by another thinner layer just below formed by expanded austenite with a high presence of carbon (back diffusion). An enhanced diffusion can be observed on AISI 304 steel comparing with AISI 316 steel (a nitrided layer thicker can be noticed in the AISI 304 steel). The mechanical strength of both steels after nitriding processes reveals significant hardness values, almost 1100 HV, on the nitrided layers.

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40

LV, Xiang, De-ning Zou, Jiao Li, Yang Pang, and Yu-nong Li. "Effect of Co on microstructure and mechanical properties of precipitation hardening stainless steel." Metallurgical Research & Technology 117, no. 1 (2020): 116. http://dx.doi.org/10.1051/metal/2020006.

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The effects of Co element on the microstructure of precipitation hardening stainless steel was investigated by metallographic microscope (OM), transmission electron microscopy (TEM) and X-ray diffractometry (XRD), and the mechanical properties were measured by tensile, hardness and impact tests. The results show that with increasing Co content, the volume fraction of reversion austenite is increased. The precipitation of ε-Cu phase is remarkably decreased, leading to the improvement of ductility, while the strength and hardness are decreased. Co element improves the strength and toughness of stainless steel through fine-grain strengthening, solution strengthening and austenitic toughening.

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41

Xu, Ming Zhou, Jian Jun Wang, Li Jun Wang, Wen Fang Cui, and Chun Ming Liu. "Microstructure Evolution of a Metastable CrMnN Austenitic Stainless Steel during Compression Deformation." Advanced Materials Research 146-147 (October 2010): 26–33. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.26.

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Microstructural evolution of a metastable 18Cr12Mn0.55N austenitic stainless steel during compression deformation was investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). TEM observation showed the occurrence of deformation-induced phase transformation and atypical deformation twin, the deformation-induced phase cannot be identified as austenite or martensite. XRD test showed that the amount of deformation-induced phase is less than the detectable limit of XRD.

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42

Wang, Tian Yi, Ren Bo Song, Heng Jun Cai, Jian Wen, and Yang Su. "Influence of Cold Rolling Reduction on Microstructure and Mechanical Properties in 204C2 Austenitic Stainless Steel." Materials Science Forum 944 (January 2019): 193–98. http://dx.doi.org/10.4028/www.scientific.net/msf.944.193.

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The present study investigated the effect of cold rolling reduction on microstructure and mechanical properties of a 204C2 Cr–Mn austenitic stainless steel which contained 16%Cr, 2%Ni, 9%Mn and 0.083 %C). The 204C2 austenitic stainless steels were cold rolled at multifarious thickness reductions of 10%, 20%, 30%,40% and 50%, which were compared with the solution-treated one. Microstructure of them was investigated by means of optical microscopy, X-ray diffraction technique and scanning electron microscopy. For mechanical properties investigations, hardness and tensile tests were carried out. Results shows that the cold rolling reduction induced the martensitic transformation (γ→α ́) in the structure of the austenitic stainless steel. With the increase of the rolling reduction, the amount of strain-induced martensite increased gradually. Hardness, ultimate tensile strength and yield strength increased with the incremental rolling reduction in 204C2 stainless steels, while the elongation decreased. At the thickness reduction of 50%, the specimen obtained best strength and hardness. Hardness of 204C2 stain steel reached 679HV. Ultimate tensile strength reached 1721 MPa. Yield strength reached 1496 MPa.

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43

Karmanchuk, I. V., A. Y. Koval', N. V. Nikitina, and L. M. Butkevich. "Microstructure of single crystals of austenitic stainless steel." Russian Physics Journal 35, no. 10 (October 1992): 899–901. http://dx.doi.org/10.1007/bf00559879.

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Penha, R. N., L. B. Silva, C. S. P. Mendonça, T. C. Moreira, and M. L. N. M. Melo. "Effect of ageing time on microstructure and mechanical properties of SAF 2205 duplex stainless steel." Archives of Materials Science and Engineering 1, no. 91 (May 1, 2018): 23–30. http://dx.doi.org/10.5604/01.3001.0012.1382.

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Purpose: SAF 2205 duplex stainless steels (DSSs) are materials characterized by a favourable combination of the properties of ferritic and austenitic stainless steels. This type of stainless steel presents good weldability, corrosion resistance especially for stress corrosion cracking (SCC). However, this steel presents an unavoidable disadvantage that is its potential microstructural instability. Although duplex stainless steels design idea is to present two main types of microstructure, other phases and carbides or nitrides can precipitate. In the case of DSS SAF 2205, in addition to austenitic and ferritic microstructure, during heat treatment processing, welding or use may occur precipitation of undesirable intermetallic phases such as chi, Widmanstätten austenite, sigma besides carbides and nitrides. The precipitation of s-phase is associated with effects that cause both reduction of toughness and decreases the corrosion resistance on austenitic, ferritic and duplex stainless steels. Design/methodology/approach: This study evaluated the aging treatment effect on hardness, impact toughness and ferrite content of a SAF 2205 duplex stainless steel. Samples were solubilized at 1150°C, quenched in water and aged at 850°C during 1, 5, 10, 30, 60 or 180 minutes. After aging, cooling was to room temperature in air. Findings: Aging time promoted s-phase precipitation and hardness increase. Hardness and ferrite volume measurements, microscopy and the prediction of sigma phase bases the discussion. Impact toughness decreased with time aging and intermetallic phase precipitation. Research limitations/implications: As future work could be performed some corrosion test, vary the cooling rate after aging, and using other techniques to identify phases. Focus the research at lower aging times to try the describe Cr partitioning process to form sigma phase. Practical implications: High aging time should be avoided for SAF 2205 DSS. Originality/value: Usually sigma-phase precipitation on DDS is correlated to welding process. This paper correlates it to aging heat treatment.

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Baranowska, Jolanta, and Vicente Amigó. "Gas Nitriding of Sintered Austenitic Stainless Steel." Defect and Diffusion Forum 312-315 (April 2011): 524–29. http://dx.doi.org/10.4028/www.scientific.net/ddf.312-315.524.

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The results concerning gas nitriding of sintered stainless steel are presented in the paper. The samples made of 316L steel were gas nitrided at temperatures between 400-550°C. The microstructure of the layer was investigated by means of light and atomic force microscopy. The phase composition was identified using X-ray diffraction. Moreover, tribological and corrosion properties of the samples were evaluated. It was demonstrated that in case of gas nitriding it is possible to obtain nitrided layers also inside open pores, which can be beneficial for corrosion response of nitrided sintered austenitic stainless steel applied in corrosive environments.

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Lopez, Juan Manuel Salgado, María Inés Alvarado, Hector Vergara Hernandez, José Trinidad Perez Quiroz, and Luis Olmos. "Failure of Stainless Steel Welds Due to Microstructural Damage Prevented by In Situ Metallography." Soldagem & Inspeção 21, no. 2 (June 2016): 137–45. http://dx.doi.org/10.1590/0104-9224/si2102.03.

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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.

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Rodriguez vargas, Bryan ramiro, Luciano Albini, Giulia Tiracorrendo, Riccardo Massi, Giulia Stornelli, and Andrea Di Schino. "EFFECT OF ULTRAFAST HEATING ON AISI 304 AUSTENITIC STAINLESS STEEL." Acta Metallurgica Slovaca 29, no. 2 (June 20, 2023): 104–7. http://dx.doi.org/10.36547/ams.29.2.1833.

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This study explores the effects of ultrafast heating on AISI 304 austenitic stainless steel. The research shows that ultrafast heating can lead to fine-grained mixed microstructures in steel, making it a potential alternative for modifying microstructure in stainless steel. The study demonstrates that a minimum temperature of 980 °C is required to achieve a fully recrystallized microstructure. The results also suggest that a lower temperature can result in a finer recrystallized grain size compared to higher temperature results. The study provides valuable insights into the impact of ultrafast heating on the microstructural constituents, recrystallization temperatures, and mechanical properties of investigated steel.

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Makhatha, ME. "Effect of titanium addition on sub-structural characteristics of low carbon copper bearing steel in hot rolling." AIMS Materials Science 9, no. 4 (2022): 604–16. http://dx.doi.org/10.3934/matersci.2022036.

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<abstract> <p>The low carbon copper-bearing steel exhibits high toughness and better weldability. In the present investigation, 0.05C–1.52Cu–1.45Mn stainless steel and its titanium added counterpart which is 0.05C–0.05Ti–1.52Cu–1.45Mn stainless steel were subjected to hot rolling. The hot rolling test followed by quenching to retain the microstructure was done using a hot-rolling mill. The rolling was done at two different temperatures of 800 ℃ and 850 ℃. The characterization of microstructure was done using electron back scattered diffraction and transmission electron microscopy analysis. The 0.05C–1.52Cu–1.45Mn stainless steel when subjected to hot rolling at a lower temperature envisaged a deformed microstructure rather transformed one. However, the same steel at a higher temperature envisages a transformed microstructure. There was no variation in hardness was observed. However, the addition of 0.05 wt% of titanium in 0.05C–1.52Cu–1.45Mn stainless steel influenced the softening and the microstructure showed some recrystallization; the hardness was decreased with the increasing rolling temperature because the solubility of titanium in the austenite phase increased with temperature which leads to suppression austenitic grain/sub-grain growth and hardness. The mean sub-grain size for 0.05C–1.52Cu–1.45Mn stainless steel was 2.75 µm. However, the addition of titanium leads to a decrease in the mean sub-grain size. A marginally larger mean sub-grain size was observed when 0.05C–0.05Ti–1.52Cu–1.45Mn stainless steel was rolled at a higher temperature. A comparatively finer precipitate of copper, titanium and oxy-silicates of Ferrous/Manganese in order of nanometer was formed during rolling at a higher temperature.</p> </abstract>

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Zhou, Rui, Xuan Wang, Cheng Liu, and Derek O. Northwood. "Self-organized Formation of Multilayer Structure in a High Nitrogen Stainless Steel during Solution Treatment." MRS Advances 4, no. 5-6 (2019): 271–76. http://dx.doi.org/10.1557/adv.2019.42.

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ABSTRACTCompared with traditional stainless steels, high nitrogen stainless steels (HNSS), have been widely used due to their high strength, toughness along with excellent corrosion resistance and low cost, formed by partial replacement of Ni (austenite-forming element) by N. The evolution of the microstructure of a Cr19Mn19Mo2N0.7 stainless steel is investigated after solution treatment at 1010, 1060, 1200 or 1250°C for 30min. A complex multilayer structure has been found under a negative pressure vacuum. A white ferritic layer at the surface is formed, and a subsurface layer with full austenitic structure and a bulk microstructure comprising of austenite and ferrite are detected. With increasing solution temperature, the surface layer thickness increases. The formation of the multilayer structure is attributed to an outward diffusion, a diffusive retardation and an abnormal accumulation of nitrogen during solution treatment.

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50

Wang, Xiaoli, Qingxian Hu, Wenkang Liu, Wei Yuan, Xinwang Shen, Fengyin Gao, Douxi Tang, and Zichen Hu. "Microstructure and Corrosion Properties of Wire Arc Additively Manufactured Multi-Trace and Multilayer Stainless Steel 321." Metals 12, no. 6 (June 17, 2022): 1039. http://dx.doi.org/10.3390/met12061039.

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Because low thermal conductivity and high viscosity are common characteristics of austenitic steel, it is easy to cause a large amount of heat accumulation in the chip area, resulting in tool edge collapse or wear, and the traditional preparation method is unsuitable for preparing large and complex austenitic steel components. Wire + arc additive manufacturing (WAAM) provides a great application value for austenitic stainless steel because it can solve this problem. The cold metal transfer (CMT)-WAAM system with good control of heat input was used to fabricate the multi-trace and multilayer stainless steel 321 (SS 321) workpiece in this study. The microstructure and corrosion properties of the SS 321 workpiece were observed and compared with those of an SS 321 sheet. The results showed that the microstructure of the SS 321 workpiece from top to bottom was regularly and periodically repeated from the overlapping remelting zone, inter-layer remelting zone, and primary melting zone. There was white austenite matrix and black ferrite, and a small amount of skeleton and worm ferrite was distributed on the white austenite matrix. The average hardness value from the top to the bottom region was approximately uniform, indicating that the workpiece had good consistency. The corrosion properties in 0.5 mol/L H2SO4 solutions were compared between the SS 321 workpiece and the SS 321 sheet. The results showed that the corrosion properties of the top region of the workpiece were better than that of the middle and bottom part, and the corrosion properties of the SS 321 workpiece were better than that of the SS 321 sheet.

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Journal articles on the topic 'Austenitic Stainless Steel-Microstructure'

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