Conditions of austenite diffusional transformation in steel of Cr–3Ni–Mo–V-composition with high austenite stability
- 1 — Ph.D., Dr.Sci. Head of laboratory Central Research Institute of Structural Materials «Prometey» named by I.V. Gorynin of National Research Center «Kurchatov Institute»
- 2 — Ph.D. Head of sector Central Research Institute of Structural Materials «Prometey» named by I.V. Gorynin of National Research Center «Kurchatov Institute»
- 3 — engineer Central Research Institute of Structural Materials «Prometey» named by I.V. Gorynin of National Research Center «Kurchatov Institute»
Abstract
The paper investigated the bainitic steel of 10KHN3MFA grade, which is characterized by the increased tendency to display structural heredity in the forgings with large cross-sections. The samples have been studied for kinetics of diffusional transformation process both under continuous cooling and isothermal conditions, as well as its microstructure. It is determined that in the range of subcritical temperatures with cooling from 900 °C in the studied steel, the initial stage of separation of the ferrite phase takes place. It is shown for the first time that the diffusional ferrite-pearlite transformation fades. Previously it was believed that the beginning of transformation under isothermal conditions proceeds to the end. It was found out that the transformation begins immediately after the beginning of isothermal holding, without the generally accepted incubation period.
Funding
Experimental research was carried out on the equipment of the Center of the common facilities «Composition, structure and properties of structural and functional materials» SRC «Kurchatov Institute»– CRISM «Prometey» with the financial support of the state represented by the Ministry of Education and Science under the agreement N14.595.21.0004, unique NRFMEFI59517X0004.