METHOD FOR ION-PLASMA NITRIDING OF PARTS FROM TOOL STEEL Russian patent published in 2016 - IPC C23C8/38 C23C14/48 C21D9/22 C23C8/24 

FIELD: metallurgy.

SUBSTANCE: invention relates to chemical-thermal treatment of articles from tool steel. Tool is heated in vacuum chamber in argon medium at pressure 0.2-0.67 Pa to temperature not lower than 450° and not above Ac₁-(50-70) °C to ensure ion cleaning of surface, then at specified temperature of heating is performed by ion-plasma nitriding in plasma of nitrogen or argon and nitrogen gas mixture with concentration of nitrogen of not less than 20 % by two-stage vacuum-arc discharge, where current of arc is (80-100)±0.5 A, and current intensity of additional anode - (70-90)±0.5 A when tool bias voltage is within range of -50 to -900 V for 0.5-2 hours, cooling is performed in chamber, and hardening and tempering is performed at standard mode for given steel to produce a nitrated layer depth 2-2.5 mm.

EFFECT: increased depth of azotised layer over a short period of time, higher wear resistance of sharpened tool made of annealed workpieces.

1 cl, 2 ex