Hot Deformation Behavior and 3D Processing Maps of Mn18Cr18N Steel

The isothermal hot deformation behavior in the ranges of 1023-1473 K (750-1200 degrees C) and 0.001-10 s(-1) for 0.53 wt% N-bearing Mn18Cr18N steel is studied with a Gleeble-3500 thermomechanical simulator. The results indicate that the peak stress decreases with decreasing strain rate and increasing temperature. The calculated deformation activation energy of the experimental steel is 449.118 kJ mol(-1) by regression analysis. At the same time, 3D processing maps are established based on experimental data and the principles of the dynamic materials model. The domain of stable deformation gradually expands with the increase in strain, while the instability region shrinks accordingly. From the microstructure of specimens and the processing maps established, it is clear that dynamic recrystallization emerges in the peak power dissipation efficiency domain, 1000-1150 degrees C/0.002-0.1 s(-1), which is the optimum region of hot working of the steel.