Research on the dynamic recrystallization behavior of GCr15 steel

The dynamical recrystallization (DRX) of GCr15 steel was investigated at deformation temperatures of 950–1150 °C and strain rates of 0.1–10 s−1 on a Gleeble-3800 thermo-mechanical simulator. The stress–strain curves at lower strain rates are typical of the occurrence of DRX and exhibit a peak in the flow stress before reaching steady state. The flow stress at higher strain rates increases rapidly to the maximum too, but followed by a steady region. The microstructures after deformation certify that DRX takes place in all specimens. And the results show that DRX occurs more easily with the decrease of strain rate and the increase of deformation temperature. Using regression analysis, the DRX activation energy of the steel, the relationship of critical strain and deformation conditions were determined. In order to determine the recrystallized fraction under different conditions, an approximate model based on the stress–strain curves was investigated, and the kinetic model for DRX was established.