Simple constitutive equations for steel at high temperature

This work develops and investigates simple unified constitutive equations to model the mechanical behavior of plain carbon steel in the austenite temperature region for use in finite element stress analysis of processes such as continuous casting. Four different forms of constitutive relations are considered: constant structure, time-hardening, strain-hardening, and simultaneous time- and strain-hardening models. Each relation is judged on its ability to reproduce experimental data from both tensile and creep tests and its ability to exhibit reasonable behavior under complex loading conditions. Three of the equations appear suitable for small strain monotonic loading conditions for a wide range of low strain rates (10^-3 to 10^-6 s^-1), high temperatures (950 °C to 1400 °C), and varying carbon contents (0.005 to 1.54 wt pct C).