Establishment of hot processing map and work hardening mechanism of 0Cr11Ni2MoVNb stainless steel during hot compression process

Abstract

True stress versus true strain curves of 0Cr11Ni2MoVNb stainless steel were obtained from isothermal compression tests on Gleeble-1500 tester over a wide temperature range from 1223K to 1433K and a strain rate range from 0.01s−1 to 10s−1. Combined with the stress-strain data during hot deformation process, work hardening mechanism of of 0Cr11Ni2MoVNb steel was investigated. Besides, the developed MATLAB code was provided to generate hot processing map to analysis the influencing rule of various deformation parameters on instability region and energy dissipation under the strain degree of 0.3, 0.5 and 0.7. The main result shows that: (1) Based on dynamic materials modeling(DMM), the processing map was established, where the flow instability maybe occur when the strain rate is higher than 0.1 s-1. (2) the temperature and strain rate range for dynamic recovery and recrystallization become lager when strain increases, besides, the globularization intensities increasing obviously with decreasing of temperature and increasing of strain rate. (3) maximum values of the deformation activation energy under various strain degree are concentrated in the deformation region with the temperature over 1373K and the strain rate nearby 0.1s-1, and then the optimum temperature and strain rate ranges for hot ring rolling at different strain of the steel are determined according to the hot processing maps.