Showing 5 results for Austenitic Stainless Steel
A. Poladi, M. Zandrahimi,
Volume 5, Issue 3 (9-2008)
Abstract
Abstract: Austenitic stainless steels exhibit a low hardness and weak tribological properties. The
wear behaviour of austenitic stainless steel AISI 316 was evaluated through the pin on disc
tribological method. For investigating the effect of wear on the changes in microstructure and
resistance to wear, optical microscopy and scanning electron microscope were used. The hardness
of the worn surfaces was measured with a micro-hardness tester. Worn surfaces were analyzed
through X-ray diffraction. Results showed that with increasing the sliding distance and applied
load, the austenite phase partially transformed to ά martensite, and there was no trace of ε phase
detected. Due to the formation of probably hard and strong martensite phase, as the sliding
distance and applied load increased, the hardness and the wear resistance of the material was
increased. Wear mechanism was on the base of delamination and abrasion.
M. Mahmoudiniya, Sh. Kheirandish, M. Asadi Asadabad,
Volume 14, Issue 1 (3-2017)
Abstract
Nowadays, Ni-free austenitic stainless steels are being developed rapidly and high price of nickel is one of the most important motivations for this development. At present research a new FeCrMn steel was designed and produced based on Fe-Cr-Mn-C system. Comparative studies on microstructure and high temperature mechanical properties of new steel and AISI 316 steel were done. The results showed that new FeCrMn developed steel has single austenite phase microstructure, and its tensile strength and toughness were higher than those of 316 steel at 25, 200,350 and 500°C. In contrast with 316 steel, the new FeCrMn steel did not show strain induced transformation and dynamic strain aging phenomena during tensile tests that represented higher austenite stability of new developed steel. Lower density and higher strength of the new steel caused higher specific strength in comparison with the 316 one that can be considered as an important advantage in structural applications but in less corrosive environment
A. Jafari Tadi, S.r. Hosseini, M. Naderi Semiromi,
Volume 14, Issue 3 (9-2017)
Abstract
Influence of formation of surface nano/ultrafine structure using deep rolling on plasma nitriding and tribological properties of the AISI 316L stainless steel was investigated. Initially, the deep rolling process was carried out on the bar-shaped specimens at 15 cycles with 0.2 mm/s longitudinal rate and 22.4 rpm bar rotation. Then, plasma nitriding treatment was applied on the as-received and deep rolled kinds at 450 °C and H2-25% Vol. N2 gas mixture for 5 h. Surface micro-hardness and un-lubricated pin-on-ring sliding wear tests were carried out on the as-received, deep rolled, plasma nitrided and deep rolled-plasma nitrided kinds. Results revealed that deep rolled-plasma nitrided kind is shown the highest wear resistance than the others, due to the further increased surface hardness achieved via the combined process.
H. Fathi, B. Mohammad Sadeghi, E. Emadoddin, H. Mohammadian Semnani,
Volume 16, Issue 3 (9-2019)
Abstract
Abstract
In the present research, the behavior of 304L austenitic stainless steel in the deep drawing process has been studied at the room temperature through experimental and finite element simulation method. Magnetic method calibrated by XRD was used to measure induced-martensite. Martensite volume fraction in the various portion of the deep drawn cup under optimum Blank Holder Force (BHF) and in the rupture location was evaluated. Findings of the present study indicated that higher martensite volume fraction occurred in the flange portion in the drawn cup due to higher strain and stress concentration in this area. Also, rupture happened at the arc portion of the wall of drawn cup with higher blank diameter due to higher strain, work hardening and martensitic transformation. Both experimental and simulation results showed that maximum LDR of 2 obtained in the forming process. All experimental procedures were simulated by LS-DYNA software, employing MAT_TRIP, and experimental results were in good agreement with the FE simulation.
Mohammad Javad Sohrabi, Hamed Mirzadeh, Saeed Sadeghpour, Reza Mahmudi,
Volume 20, Issue 4 (12-2023)
Abstract
Deformation-induced α΄-martensite generally forms at shear bands in the coarse-grained austenite, while it nucleates at grain boundaries in the ultrafine-grained (UFG) austenite. The available kinetics models are related to the nucleation on the shear band intersections, and hence, their application to investigating the kinetics of α΄-martensite formation for the UFG regime cannot be justified. Accordingly, in the present work, the general Johnson–Mehl–Avrami–Kolmogorov (JMAK-type) model was implemented for comparing the kinetics of α΄-martensite formation in the UFG and coarse-grained regimes using an AISI 304L stainless steel. On the experimental front, the X-ray diffraction (XRD) patterns and the electron backscattered diffraction (EBSD) maps were used for phase and microstructural analyses, respectively. It was revealed that the simple JMAK-type model, by considering the dependency of the volume fraction of α΄-martensite on the strain, is useful for modeling the experimental data, predicting the nucleation sites based on the theoretical Avrami exponents, and characterizing the transformation kinetics at low and high strains.
