Change in the structure of steel ShKh15SG after hot deformation during HTTMT

Abstract

1. The hardening effect after HTTMT depends on the combination of the austenitizing and deformation temperature and the degree of deformation and isothermal holding time between the end of deformation and quenching, which determine the development of fragmentation within the original hot worked grains. 2. With differences in the conditions of heating, deformation, and isothermal holding, the rate of dynamic recrystallization processes varies, leading to the formation of fragments (tens of microns), detected in ordinary metallographic analysis, and a fine network of subboundaries within the original grains. 3. Fine subgrains (1–3μ) due to dynamic polygonization are formed within the fragments during hot deformation, since the stages of dynamic recrystallization in place and dynamic polygonization overlap. The structure of steel hardened by HTTMT can be determined accurately only by a combination of electron microscopic and metallographic analyses.