Formation of the microstructure of the transition zone in steel subjected to interrupted quenching and structural inhomogeneity in two-stage cooling

Abstract

1. After a TMT with interrupted quenching or two-stage cooling, a transition zone is formed in the cross section of the specimen between the surface layer and the central zone. 2. In the process of interrupted quenching, the ferritepearlite structure of the transition zone disintegrates or we observe the formation of products of a polymorphic diffusionless transformation with structural-morphological features of martensite. After a TMT with two-stage cooling, a specimen of steel 35 possesses structural inhomogeneity over the cross section; the material has a layered structure. 3. The formation of the microstructure of the transition zone in TMT with interrupted quenching and of structural inhomogeneity in TMT with two-stage cooling is connected with the elevation of the stability of austenite and the redistribution of carbon between the layers under the action of phase stresses and their concentration on the interface of the α- and γ-solid solutions.