Mechanical behaviour of steels under hot-working conditions

The constitutive behaviour of a C-Mn steel (BS grade 430) is described in terms of the exponential-saturation equation earlier proposed by Sah et al., modified accordingly to include dynamic recrystallization effects. The Sellars-Tegart-Garofalo model is employed for describing the correlation of the stress parameters involved in this equation with temperature and strain rate. The Newton-Gauss method is used for the optimization of the seven parameters that enter into the constitutive equation. The resulting constitutive equation is observed to describe quite closely both the stress-strain behaviour and the work-hardening rate of the material.