Process Encyclopaedia

Case hardening

Other names / variants: Carburising, Nitriding

Overview

Carburising and nitriding are both forms of case hardening and are primarily used to improve the mechanical properties of the surfaces of steel components. The component to be treated is put into a special gas atmosphere (gas carburising) at a high temperature. The process works by altering the surface chemistry because of the diffusion of gas into the solid.

The process is quite slow because it depends on diffusion, so it is normally automated by using a conveyor belt. It is also possible to use certain liquids (liquid carburising) which speed up the diffusion so cycle times are shorter.

The main advantages of these processes are: the main disadvantages are: