METHOD OF CARBURIZATION Russian patent published in 1995 - IPC

FIELD: metallurgy. SUBSTANCE: method provides for heating, carburization under temperature over Ac₃, discrete short cooling, for example, by dipping in boiling layer or by neutral gas blasting. Cooling in every cycle is stopped as surface is cooled to temperature of 600 750 C and repeated after surface is heated due to accumulated heat. Cycles are repeated till temperature of pieces after heating is lowered to below Ar₁. Then heating for hardening and hardening itself are carried out. Method allows to increase depth of hardened layer 1.5 3 times as much, to increase hardness up to 600-700 kg/mm² and more at bigger depth and to decrease time period of some cooling to 1.5 2.5 minutes. EFFECT: increased depth of layer of high hardness layer due to much uniform dispersion of carbon. 2 cl, 1 dwg, 2 tbl