Evolution of Grain Size in 34CrNiMo6 Steel as a Function of Thermo-mechanical Process Route

Abstract

The main purpose of the isothermal deformation processes is to quantify the austenite grain size at different deformation conditions and determine the stress strain behaviour of the 34CrNiMo6 low alloy steel. In this study we have simulated the deformation process conditions experienced in the large scale forging of 34CrNiMo6 low alloy steel in order to understand and optimize the thermo-mechanical process parameters that determine microstructure and thus the final mechanical properties. Isothermal hot working tests over the temperature range of 900°C - 1260°C, strain rates of 0.1, 0.5 and 1s¯¹, and strains of 0.4, 0.6 and 0.8, while a range of microscopy methods will be used for microstructure analysis. The peak stress and peak strain for initiation of dynamic recovery (DRV) and recrystallization (DRX) at different temperatures and strain rates were calculated. The relation between grain size diameter and both of Zener-Hollomon parameter and deformation temperatures with changing of strain rate at both austenitising temperatures of 1100°C and 1260°C were determine. All these data are going to be used through the general constitutive equations to determine the hot working constants