Viscoplastic Behavior and Modelization of an Austenitic Stainless Steel (17-12 SPH) at High Temperature (T = 600°C), Under In and Out of Phase Cyclic Tension-Torsion Loading

Abstract

The results of experiments performed on an austenitic stainless steel of the type 316L at a temperature of 600°C are presented. The tests were made under both unidirectional (1D) and bidimensional (2D) cyclic tension-torsion loading, both in and out of phase with one (case of 2D ratchet) or two cyclic components. For the 2D loadings, it is shown that a weak supplementary hardening ΔH+ appears which is mostly a function of the degree of phase difference φ between the strain components and the ratio R between the maximum amplitudes of these components. These observations conform qualitatively to those already reported for ambient temperature but quantitatively it is shown that the maximum amplitude of this supplementary hardening is a strongly decreasing function of the temperature. A simple phenomenological formulation is proposed which, when integrated into a unified viscoplastic model developed elsewhere, leads to a correct representation of the experimental results.