The results of the study of anhydrous carbohydrogenation influence in a smoldering discharge on the
microhardness of a hardened 12XH3A steel layer depending on the propane content and pressure of the gas environment
are presented in the paper. In accordance with the developed methodology of studying the influence of
technological parameters of the process of carbonylation on the properties of structural materials, optimal modes
of hardening of 12XH3A steel, depending on the operating conditions have been found.