FIELD: metal working and mechanical engineering. SUBSTANCE: invention relates to surface strengthening of machine parts using environmentally harmless technologies. Method includes determining critical rate of hardening of diffusion layer in order to properly select hardening medium when hardening parts; nitrocementation of parts at temperature below A with adding triethanolamine into furnace; and hardening of parts followed by light annealing. Method makes it possible to avoid using high temperatures (above 900 C), retain viscous kernel, and obtain high hardness and wear resistance of diffusion layer with its being sufficiently deep. Method is e.g. applicable when manufacturing parts for production treble in oil production industry. Method does not require non-standard equipment. EFFECT: enhanced efficiency of procedure. 2 cl, 3 tbl
