A Study of Decomposition of Supercooled Austenite in High-Strength Medium-Carbon Complexly Alloyed Cold-Resistant Steels

Special features of structural and phase transformations, position of critical points, quantitative parameters of the structure, and hardness under continuous transformation of supercooled austenite in steels 30KhNMFRA, 30KhGNMFRA and 30KhN3MFRA are determined. Thermokinetic diagrams of decomposition of supercooled austenite in the steels are plotted using a Gleeble 3500 research complex. Recommendations are developed for selection of chemical composition and cooling rate for billets in order to provide a high strength and enough impact toughness of the steels after quenching and low tempering. The results may be used for development of high-strength cold-resistant steels and modes of their heat hardening.