Prediction of Hot Deformation Flow Curves of 1.4542 Stainless Steel

Abstract

The ability of four constitutive equations, Johnson–Cook (JC), Zerilli–Armstrong (ZA), Arrhenius-type constitutive equations and a newly developed phenomenological model for describing the hot flow behavior of 1.4542 stainless steel was evaluated. The hot flow curves were obtained from hot compression tests in the temperature range of 900–1050 °C and at strain rates of 0.001–1 s−1. The JC model was not able to predict the softening part of the flow curves owing to the separated effects of strain, strain rate and temperature on the flow stress. The original ZA model was found to be useful at large strains but the overall consistency between the experimental and the calculated flow curves was not good. The subsequent modifications of the ZA model for low strain levels resulted in acceptable predictions. It is observed that the Arrhenius-type predicted flow curves well agree with the experimental results especially at low strain rates. However, at high strain rates where the steady state condition is shifted to large strains, some deviations were observed at low strain levels. Finally, a phenomenological model was constructed based on the nonlinear estimation of work hardening. The flow curves developed by the model could predict the experimental ones with satisfactory precision.