Flow Behavior and Dynamic Recrystallization Mechanism of CSS-42L Bearing Steel During Hot Compression Deformation

In this work, flow behavior and dynamic recrystallization (DRX) mechanism of a low carbon martensitic stainless bearing steel, CSS-42L, were investigated using a thermomechanical simulator under the temperature and strain rate ranges of 900 to 1100 °C and 0.1 to 20 s⁻¹, respectively. The Arrhenius-type constitutive equation was established based on the flow stress curves. Moreover, the peak stress decreased with the increase in deformation temperature and the decrease in strain rate. There were two DRX mechanisms during hot deformation of the current studied steel, the main one being discontinuous dynamic recrystallization mechanism, acting through grain boundary bulging and migration, and the auxiliary one being continuous dynamic recrystallization mechanism, working through the rotation of sub-grains. On the basis of microstructural characterizations, power dissipation maps and flow instability maps, the optimized hot deformation parameters for CSS-42L bearing steel were determined as 1050 °C/0.1 s⁻¹ and 1100 °C/1 s⁻¹.