Case hardening is a simple method of hardening steel. It is less complex than through hardening and is used for steels with a low carbon content.
Case hardening involves heating to high temperatures in a carburizing atmosphere, thereby increasing the carbon content at the surface of the component. Following heat treatment, the steel is quenched. The result is a component with a hard surface and a comparably soft core. This gives the case hardened steel extra durability as the core retains the ability to absorb shock, while the hard outer case provides extra strength and durability.