Thermal deformation behavior and microstructural analysis of 12Cr13 martensitic stainless steel
Based on the isothermal hot compression experimental data,the flow stress model and the hot processing maps for 12Cr13 steel were constructed with deformation temperatures of 950-1150℃and strain rates of 0.1-10 s-1.By the study of the microstructural evolu-tion law of metal during thermal deformation process and the optimization the process,the large angle grain boundary and the grain bound-ary density of martensite were significantly increased.The research results show that under the condition of low temperatures and low strain rate(950℃/0.1 s-1),the atomic vacancy diffusion and dislocation slip are difficult,dynamic recrystallization is insufficient,and dy-namic recovery dominants the deformation mechanism.However,under the condition of high temperature and medium strain rate(1100℃/1 s-1),the number of recrystallized grains increases significantly,which exhibits the characteristics of serrated discontinuous dynamic recrystallization.The grains are refined and the strength and toughness of the material are improved.In the meantime,the proportion of the δ ferrite phase is relatively small,the δ ferrite phase distribution is equiaxial,and the grain boundary edges morphology is stable.Fur-ther research finds that both the deformation temperature and strain rate have a significant effect on the solid-state phase transformation in martensitic steel.Higher strain rate has a positive effect on the precipitation of the δ ferrite phase,while the effect of deformation tempera-ture is attributed to the driving force of solid-state phase transformation.
NETL
NSTL
万方数据
