Constitutive modelling for high temperature behaviour of 12CrNiMoWV martensitic stainless steel

Abstract

Hot deformation behaviour of 12CrNiMoWV steel was investigated by hot compression tests on a Gleeble 1500 simulator in a wide range of temperatures (950–1150°C) and strain rates (0·1–10 s⁻¹). The results show that the stress–strain curves at lower strain rate (0·1 s⁻¹) exhibit a single peak stress, indicating a typical dynamic recrystallisation (DRX) behaviour of the steel. In addition, further microstructural observation confirms the occurrence of the DRX behaviour. The stress level decreases with increasing deformation temperature and decreasing strain rate, which can be predicted by the Zener–Hollomon Z parameter in the Arrhenius type equation. The influence of strain was incorporated in the constitutive equation by considering the effect of strain on the material constants. By taking the arithmetic average of the mean errors of flow stress for each of the stress–strain curves, almost all the values are under 5%, which validates the efficiency of the constitutive equation in describing the hot deformation behaviour of this steel.

Keywords:

• 12CrNiMoWV steel
• Hot deformation
• Flow stress
• Constitutive equation
• Microstructural evolution

The present investigation has been carried out with the support from Dongfang Turbine Co., Ltd, Deyang, China.