METHOD FOR GAS, LOW-TEMPERATURE NITROCARBURISING OF TOOLS MADE OF HIGH-CHROMIUM DIE STEELS (SATURATION LAYERS FROM 0.08 TO 0.15 mm) WITH A MINIMAL CARBONITRIDE HIGH-NITROGEN SURFACE LAYER IN VACUUM FURNACES Russian patent published in 2023 - IPC C23C8/32 

FIELD: metallurgy.

SUBSTANCE: invention relates to thermochemical treatment of tools made of stainless die steels X12MF, 40X13, and other steels, and can be used to harden all types of die tools operating in settings of intense friction and dynamic loads. Method for low-temperature nitrocarburising of die tools made of high-chromium stainless die steel in a vacuum draw furnace includes the following operations. Evacuating the draw furnace up to 10^-2 mmHg; filling with ammonia up to 100 mmH2O while heating to a temperature of 520 to 570 °C and holding for 2 hours in order to remove the oxide film from the surface of the tool. Ammonia and exothermic gas are then supplied at a ratio of 1:1, holding for 6 to 15 hours, followed by cooling in a nitrogen gas medium to a temperature of ≤200 °C.

EFFECT: increase in the operating life of die tools made of high-chromium stainless die steels in an environmentally sustainable gas process by a factor of 2–3 and a reduction by a factor of 3 in the costs as compared to the cyanide bath treatment method.

1 cl, 1 ex