Hot ductility and microstructure in casted 2205 duplex stainless steels

The effects of the warm parameters (the strain rate and forming temperature) on the deformation behavior and microstructure in 2205 duplex stainless steels (DSS) was studied. The hot deformation behavior of 2205 DSS was investigated through hot tensile and hot compression testing on a Gleeble-1500 thermal-mechanical simulator within the temperature range of 1023–1623 K, in order to determine their reduction of area, resistance to deformation, deformability, and microstructure. The experimental results show that the hot deformation curves of the test steel has a high temperature brittlement region at temperatures higher than 1523 K, and the optimum hot ductility region is in the temperature range of 1423–1523 K. The microstructure of the steel obtained after hot deformation is much finer compared with the as-cast microstructure of the steel. It was found that dynamic recovery only occurs within the γ-phase during hot deformation, but the δ phase undergoes dynamic recrystallization. Small secondary γ′ phase islands are precipitated on the δ matrix, as demonstrated by TEM analysis, which can markedly promote hot ductility behavior.