Influence of Strain Rate on TRIP Effect in SUS301L Metastable Austenite Steel

Abstract

In order to investigate the effect of strain rate on TRIP effect in metastable austenitic steels, tensile deformation behavior of a JIS-SUS301L steel was examined at wide range of strain rates between 103/s and 10−3/s, in addition of the comparison with data of stable austenitic steel (JIS-SUS310S). Concerning of the SUS301L steel, the 0.2% proof stress increased and the uniform elongation decreased with increasing of strain rate. The tensile strength decreased with an increase in strain rate between 10−3/s and 101/s and then increased again at strain rate more than 101/s. The significant difference between the strain rate dependences on tensile strength and uniform elongation of SUS301L and SUS310S was clarified especially at strain rates between 10−3/s and 100/s. As far as the effect of strain rate on stress-induced martensitic transformation behaviors is concerned, the volume fraction of stress-induced martensite at the same true strain decreased with increasing of strain rate. These stress-induced transformation behaviors were associated with the tensile strength and uniform elongation of SUS301L steel between 10−3/s and 100/s. The conditions of stress-induced martensitic transformation in order to obtain better uniform elongation at a high strain rate of 100/s were discussed by the calculations using the Weng secant method.