Influence of cerium on hot workability of 00Cr25Ni7Mo4N super duplex stainless steel

The effect of Ce on hot workability of 00Cr25Ni7Mo4N steel melted in vacuum induction furnace was studied by Gleeble thermal simulation machine and scanning electron microscopy (SEM). The results showed that ductility of the steel with Ce addition was increased significantly because of increasing content of austenite, segregation of Ce at grain boundaries and modification of inclusion. The optimum range of Ce content in the steel was 0.030 wt.%–0.047 wt.%, and the optimum value was about 0.047 wt.%. The effect of rare earth on the improvement of hot workability would decrease after adding 0.062 wt.% Ce because of generation of bigger aggregated inclusions and formation of brittle intermetallic phases (Ce-Fe-Cr-Mn-Mo). The temperature of steady plastic deformation of the steel with Ce addition was reduced to 1000 °C at a strain rate of 10/s and 1050 °C at a strain rate of 50/s, respectively.