The kinetics and microstructural evolution during metadynamic recrystallization of medium carbon Cr–Ni–Mo alloyed steel

The metadynamic recrystallization (MDRX) behavior of a medium carbon Cr–Ni–Mo alloyed steel 34CrNiMo was investigated using two-stage hot compression test on a Gleeble thermal-mechanical simulator in the temperature range of 1273–1423 K, strain rate range of 0.1–5.0 s−1, and interval times of 0.5–5 s. The softening of the flow stress at the second stage of compression and microstructure observation confirm the occurrence of MDRX at the elevated temperatures within very short interval time. Then the MDRX softening fraction was calculated based on the flow stress curves. The results indicate that the MDRX softening fraction increased with increasing interval time, deformation temperature, and strain rate. The kinetics of MDRX softening behavior was established using Avrami equation and the apparent activation energy of MDRX for 34CrNiMo steel was evaluated as 93 kJ/mol. The predicted results show good agreements with the experimental ones, indicating the efficiency of proposed kinetics equation.