Constitutive Modeling of 17-4PH Stainless Steel Sheet at Elevated Temperature and Statistical Optimization

The tensile flow behavior of 17-4PH stainless steel sheet was investigated from 650 °C to 850 °C at strain rates of 10−4 to 10−1 s−1. The result indicates that work hardening and dynamic recovery are exhibited in the tensile test in the temperature lower than 750 °C, and a steady stage of stress occurs higher than 750 °C because of dynamic recrystallization. After a step-by-step procedure for data analysis in the hot tensile test, the original constitutive model was given. Considering the strain compensation, several revised constitutive models of Arrhenius-type were constructed with statistical optimization and multi-strain correction. The comparison shows perfect accurate flow predictions through multi-strain modified models. Meanwhile, the flow behavior of random conditions is predicted accurately by a single correction model with Tikhonov regularization.