Analysis of the mechanisms of hardening of high-carbon steels during surface treatment with a highly concentrated plasma jet

The microstructure, phase composition and parameters of the crystalline structure of high-carbon steels (65G, U8 and U10) after plasma surface hardening were studied. It has been established that the strengthening of martensite is caused by its solid-solution strengthening, an increase in the dislocation density, the presence of a large number of subboundaries, and the release of nanodispersed carbides during self-tempering. This leads to a 3.5-4.5 times increase in hardness compared to the initial state and by 120-170 HV compared to volumetric hardening. As a result of the research, a methodological approach to controlling structure formation was developed for the process of plasma surface hardening (nanostructuring) of high-carbon steels.