Strain rate dependence of strength-differential effect in two steels

Tensile and compression tests have been performed on specimens of steels 30CrNiMo8 and 25CrMo4 at strain rates from quasi-static to high strain rates up to ≈ 5x103s-1. The flow stress under tensile loading shows a different behaviour than that under compression. Constitutive equations are developed to describe the behaviour in both cases. The strength-differential values are calculated from experimental data and from constitutive equations, and are presented as a function of strain and strain rate