Nitrocarburising is a variation of the case hardening process. It is a thermochemical diffusion process where nitrogen, carbon, and to a very small degree, oxygen atoms diffuse into the surface of the steel part, forming a compound layer at the surface, and a diffusion layer. This process is done mainly to provide an anti-wear resistance on the surface layer and to improve fatigue resistance. The process also increases abrasion and wear resistance and improves bending and contact fatigue properties. The process also decreases a part’s coefficient of friction. It also forms a thin, corrosion-resistant layer of iron oxide which significantly increases corrosion resistance.

Benefits

• Relative low cost
• High resistance to wear
• Excellent scuffing and seizure resistance
• Fatigue properties improved by up to 120%
• Considerably improved corrosion resistance
• Good surface finish
• Negligible shape distortion
• Predictable growth characteristics
• Alloy substitution – plain carbon steels replacing low alloy steels.

Application & Materials

Advantages of the process include the ability to harden materials which are not pre-hardened, the relatively low temperature of the process which minimises distortion, and relative low cost in comparison to carburising or other case hardening processes.