Effect of austenite deformation in high-temperature thermomechanical treatment on stability of high-carbon martensite during low tempering

The effect has been studied of peculiarities of fine structure of hot-deformed (by a high-temperature mechanical treatment) austenite upon the change in the structure of martensite in the two-phase breakdown stage by considering 80Kh5 steel. The quantitative evaluation of two-phase breakdown of martensite on low tempering is made using the X-ray diffraction method. It is shown that lattice parameters of tempered martensite are governed by the degree of the two-phase breakdown. The high-temperature mechanical treatment, as a rule, accelerates self-tempering in hardening cooling, whereas its effect upon the two-phase breakdown of martensite in low tempering depends on the conditions of hot deformation of austenite