What is heat treatment and why is it done?

Heat treatment can be described as a combination of operations or processes in which cooling and heating of an alloy or metal is done in order to obtain desirable characteristics without changing compositions. Some of the purpose or motives of heat treatment are as below:

> In order to improve hardness of metals.

> For the softening of metal.

> In order to improve machinability of the metal.

> To change grain size.

> To provide better resistance to corrosion, heat, wear etc.

Heat treatment is normally performed in the subsequent ways:

> Annealing

> Normalizing

> Hardening

> Spheroidising

> Surface or case hardening

> Tempering