A Study of the Effect of Nickel on Structural and Phase Transformations and Properties of High-Strength Medium-Carbon Complexly Alloyed Steel

The effect of nickel content in a high-strength medium-carbon complexly alloyed steel on the structural and phase transformations, location of critical points, quantitative parameters of microstructure and critical quenching rate is studied. Thermokinetic diagrams of decomposition of supercooled austenite in the steel with original composition are plotted and the characteristic types of microstructure forming under cooling at different rates are described. The effect of nickel on the combination of mechanical properties of thick rolled sheets after quenching and low-temperature tempering is determined. The results obtained may be used for development of high-strength cold-resistant steels and modes of their heat hardening.