|Case hardening steels are a group of suitably alloyed low carbon steels. These steels, when heat treated, absorb and diffuse carbon onto the surface. This is known as Carburization.
The addition of alloying elements improves hardenability, much the same as with High Tensile steels. When quenched, following carburizing, a hard wear resistant layer is formed, supported by a High Tensile core. The alloy additions also allow the use of slower quenching methods to minimise distortion. Case hardening steels are selected taking into account the required core strength and the susceptibility of the components to distortion.