Carbonitriding is a metallurgical surface modification technique that is used to increase the surface hardness of a metal, thereby reducing wear.

Carbon Nitriding

Carbonitriding is a case hardening process similar to Carburizing. It is generally performed at lower case hardening temperatures with the addition of nitrogen (via NH3 gas). This increases wear resistance and surface hardness through the creation of a hardened surface layer, which is diffused at these lower temperatures. The diffusion of nitrogen at these lower temperatures provides a more resistant case and increases the hardenability of low carbon steels. Carbonitriding is also well suited for Thrust Washers and small stampings that require reduced distortion and wear resistant case properties. Normal processing parameters for Carbonitriding range from 1475-1600°F (802-871°C). The atmosphere consists of 0.5 to 0.8% carbon and 0.2-0.4% (< 5%) nitrogen. Case depths for Carbonitriding are generally much less than that of Carburized parts varying from a low of .003 to .030 inches (.08mm to .76mm). Parts are commonly quenched in oil and tempered at range of 300-350°F (149-177°C) to reduce distortion and brittleness.