Effect of non-isothermal deformation of austenite on phase transformation and microstructure of 22SiMn2TiB steel

The microstructure evolution and phase transformation of high strength 22SiMn2TiB steel during non-isothermal deformation were investigated in detail. The results indicate that deformation temperature range and amount play a predominant role in phase constitution and volume fraction of the microstructure formed in the process of the non-isothermal compressive deformation. The start martensitic phase transformation temperature Ms is monotonously decreased with the deformation amount and slightly influenced by the deformation rate, and not affected by the cooling rate and initial deformation temperature. The diffusional transformation, such as polygonal ferrite and bainitic ferrite, is promoted by the non-isothermal deformation of austenite under specific circumstances where the deformed austenite passes through its transformation temperature region.