Effect of W addition on hot deformation and precipitation behaviors of 19Cr2Mo ferritic stainless steel

The hot deformation behavior of 19Cr2Mo and 19Cr2Mo1W ferritic stainless steels was studied by using uniaxial hot compression tests on a thermomechanical simulator. The hot deformation was carried out at temperature ranging from 800 to 1150 °C and strain rates from 0.01 to 10 s⁻¹. Microstructure change and precipitation behavior during hot deformation were investigated by optical microscopy, electron probe microanalysis and transmission electron microscopy. The effects of temperature and strain rate on deformation behavior were obtained by a classical equation in Zener–Hollomon parameter. Since W addition to 19Cr2Mo1W steel could refine the size of the precipitates to enhance the precipitation strengthening and also had the effect of solution strengthening, the dynamic recrystallization, dynamic recovery and grain growth of 19Cr2Mo1W ferritic stainless steel were inhibited to a certain extent. The precipitate size of 19Cr2Mo1W steel was finer than that of 19Cr2Mo steel under the same deformation condition, which is due to the fact that the atomic diffusion is suppressed by W addition. W addition increased the amount of Laves phase in 19Cr2Mo1W steel, and thus Laves phase in 19Cr2Mo1W steel could be formed at higher temperature than that in 19Cr2Mo steel.