Constitutive equation to predict elevated temperature flow stress of V150 grade oil casing steel

The true stress–strain data from isothermal hot compression tests, in a wide range of temperatures (1173–1473 K) and strain rates (0.01–10 s−1), were employed to study the deformation behavior and develop constitutive equation of V150 grade oil casing steel based on an Arrhenius-type equation. The flow stress increases with the decrease of deformation temperature and the increase of strain rate, which can be represented by Zener–Hollomon parameter in an exponential equation. The influence of strain was incorporated in the developed constitutive equation by considering the effect of strain on material constants. The flow stress predicted by the constitutive equation shows good agreement with the experimental value through the whole experimental temperature and strain rate range except a slight deviation for predicting the stress deformed at 1173 K under 0.01 s−1, and the average relative error is 4.21%.