Visco-plastic constitutive models of steel at high temperature

Two constitutive elasto-visco-plastic models are adopted to simulate the behavior of plain carbon steel at high temperature, specifically at the austenitic range (950–1300°C), being particularly appropriate for the numerical simulation of casting and hot-working processes. The response in hardening, creep and non-uniform loading conditions is analyzed and compared with experimental data. An efficient numerical integration scheme is proposed and its accuracy is evaluated using iso-error maps. The consistent isothermal tangent matrix is computed and the final models are implemented into an FEM code. Several tests are performed to evaluate the accuracy and robustness of the integration scheme. Finally an application concerning the analysis of the thermal stresses produced at the early stage of a steel continuous casting process is shown.