STRAIN RATE SENSITIVITY OF FLOW-STRESS AT LOW-TEMPERATURES IN 304N STAINLESS-STEEL

Strain rate and temperature effects on the flow stress of 304N stainless steel were investigated using data obtained from torsion tests on thin-walled tubular specimens, at given strain rates of between 10(-3) and 10(3) S-1 with temperatures ranging from 83 to 296 K. Initially, the apparent strain rate sensitivity of the flow stress, obtained at test temperatures of 83, 153, 213, and 296 K, was examined. The strain dependence and the strain rate dependence of the mechanical threshold stress (the flow stress at 0 K) at strains less than 0.1 and at strain rates of 2.4 x 10(-3) and 8.3 x 10(2) S-1, is also discussed. It was concluded from the experimental results that the mechanical threshold stress depends not only on the strain but also on the strain rate.