Hot working behavior of a nitrogen-alloyed Fe-18Mn-18Cr-N austenitic stainless steel

The hot workability of a nitrogen-alloyed Fe-18Mn-18Cr-N austenitic stainless steel was investigated through hot compression tests using a Gleeble simulator in a temperature range of 700-1100 °C and at strain rates of 0.01-5 s−1. From stress(σ)-strain(ε) curves obtained in the hot compression tests, a processing map was established to estimate the hot workability, based on the dynamic material model (DMM). The processing map predicted that the optimum hot working regimes are in the temperature range from 1050 °C to 1100 °C at strain rate of 0.01 s−1. After the hot compression tests, intergranular cracking arose under most conditions, except for the optimum hot working condition predicted by the processing map. This study discusses the cause of the intergranular cracking in terms of the precipitation of intergranular Cr2N particles. In addition, hot ductility tests were carried out for a better understanding of the decrease in the hot workability, and a significant loss of ductility was observed with intergranular Cr2N precipitation.