Nitriding

Nitriding is a process of getting superhard surface. However, it can only be employed effectively for alloy steels. In this operation metal is heated up in presence of ammonia at a temperature between 600 to 650^oC. The nitrogen (obtained by the dissociation of ammonia) combines with the surface constituents of the alloy to form extremely hard nitrides. This procedure is quite time consuming but requires no further heat treatment. The surface of nitrided part does not need machining. Wear resistance, fatigue strength and resistance to corrosion also increase by nitriding.