Surface Treatment

Numerous industrial application need a hardwear-resistant surface called as the case, and a relatively tough, soft inside called as the core. There are five principal methods of case or surface treatment.

a.    Carburizing
b.    Nitriding
c.    Cyaniding or carbonitriding
d.    Flame hardening
e.    Induction hardening

The first three methods modified the chemical composition carburizing by the adding up of carbon, nitriding by the addition of nitrogen and cyaniding by addition of carbon and nitrogens both. The final two methods do not change chemical composition and are essentially shallow-hardening methods. In flame & induction hardening the surface should be capable of being hardened, in the sense that appropriate carbon percentage is exist. These methods were described and thus not repeated here.