Low-cycle Fatigue Behavior and Constitutive Relations for a Ferritic Stainless Steel at Elevated Temperatures

Abstract

In this paper, the tensile and strain-controlled cyclic deformation behavior of a ferritic stainless steel which is developed for the exhaust manifold of automobiles is evaluated experimentally at different temperatures. The effect of temperature on monotonic tensile responses such as yield strength and ultimate tensile strength and the effect of temperature and strain amplitude on the evolution of peak stress are assessed. The objective of this study is also to reveal the mixed mode of cyclic hardening–softening behavior of the ferritic stainless steel under strain-controlled fatigue test conditions. A parameter, critical accumulated plastic strain, is introduced to the constitutive equations for the material for describing the hardening - softening responses. The nonlinear constitutive equations for describing the cyclic responses are implemented into Finite Element code using determined parameters for obtaining numerical simulation. The stabilized hysteretic responses obtained from experiment and predicted from numerical simulation are compared and found to be realistic.