Research on the Thermal Plasticity of the 18Mn-18Cr-0.77N-2Mo High Nitrogen Austenitic Stainless Steel

摘要

Hot compression tests of the 18Mn-18Cr-0.77N-2Mo high nitrogen austenitic stainless steel were performed on a GLEEBLE-2000 thermomechanical simulator under different deformation temperatures and strain rates. The microstructure of the compression samples were observed by optical microscope. The model of the resistance to deformation was built, and the recrystallization activation energy, stress exponent and other parameters were obtained through analyzing the experimental data. The dynamic recrystallization model was established, and the distribution map of the dynamic recrystallization critical condition was given. The microstructure of the compression samples showed that there were equiaxed grains on the edge of the samples and recrystallization grains in the core. Under the same strain rate, the dynamic recrystallization became more sufficient under higher deformation temperature. But the grain coarsened and the plastic plasticity decreased when the temperature was above 1150°C. The recrystallization grain size was bigger and the amount of recrystallization grain became more under lower strain rate.