Dynamic Recrystallization Behavior of GCr15SiMn Bearing Steel during Hot Deformation

Abstract

The hot deformation behavior of GCr15SiMn steel was studied through high temperature compression tests on the Gleeble-1500 thermal-mechanical simulator. The initiation and evolution of dynamic recrystallization (DRX) were investigated with microstructural analysis and then the process variables were derived from flow curves. In the present deformation conditions, the curves of strain hardening exponent (n) and the true strain (ɛ) at the deformation temperature of 1423 K and strain rates of 0.1, 1 and 10 s−1 exhibit single peak and single valley. According to Zener-Hollomon and Ludwik equation, the experimental data have been regressed by using linear method. An expression of Z parameter and hot deformation equation of the tested steel were established. Moreover, the Q values of GCr15SiMn and GCr15 steels were compared. In order to determine the recrystallization fraction under different conditions, the volume fraction of DRX as a function of process variables, such as strain rate (ɛ), temperature (T), and strain (ɛ), was established. It was found that the calculated results agreed with the microstructure of the steel at any deformation conditions.