NEW FORMULA FOR CALCULATING FLOW CURVES FROM HIGH-TEMPERATURE CONSTITUTIVE DATA FOR 300 AUSTENITIC STEELS

The high temperature flow curves for 301, 304 and 317 stainless steels can be calculated up to the peak stress sigma(p) and peak strain epsilon(p) by: sigma/sigma(p) = [(epsilon/epsilon(p)) exp(1 - epsilon/epsilon(p))]c. The values of sigma(p) may be derived from the sinh-Arrhenius constitutive equation for which the constants have already been published based on torsion tests. Epsilon(p) is shown to be linearly related to sigma(p) for each alloy. The values of the shape constant c are shown to have averages of 0.203 for 301, 0.216 for 304 and 0.200 for 317 with average errors of less than 2.6%. The value of c decreases only slightly with rising strain rate and declining temperature. An average value of 0.204 (including 316 with c = 0.193 previously published) may be employed for all the steels without significant increase in the error.