Nitriding of titanium carbide-steel materials

Abstract

A study was made of the nitriding of TiC-Kh6V3M steel materials in ammonia; the variable parameters were titanium carbide content (0.40%), amount of combined carbon in the TiC (18.2 and 19.2%), and physicochemical treatment temperature (500, 750, and 1020°C) and time (30–60 min). Nitriding at temperatures of 500 and 1020°C with subsequent oil quenching increased the hardness of the materials, which was a result of diffusional impregnation of the steel binder with nitrogen. Increasing the duration of impregnation, lowering the amount of TiC in the alloys, and decreasing the deficiency of carbon in the TiC had a beneficial effect on nitriding. The thickness of the nitrided layer was determined by layer-by-layer phase analysis and measurements of the microhardness of the steel binder on transverse microsections. It is recommended that nitriding at 500°C should be the final operation, but when it is performed at about 1000°C it should be followed by quenching.