Strain-Rate-Dependent Stress-Strain Curves for 304 Stainless Steels in Wide Range of Strain Rate

Abstract

In this study, tensile tests of austenitic stainless steel 304 at room temperature were performed under various strain rate conditions ranging from 0.001/s to 1,000/s using smooth round bar specimens. From experimental stress-strain data, stresses at various strain levels were extracted and the fitting results using the Johnson-Cook strength model were compared. As the strain rate increases, yield strength increases monotonically, but tensile strength decreases and then increases. Uniform elongation also decreases and increases slightly with the increasing strain rate. These trends are related to the strain-induced transformation of metastable austenite γ phase to α’-martensite phase. Because of these complex behaviors, fitting results using the Johnson-Cook strength model vary depending on the strain level.