Heat treatment is carried out to improve all properties of the material (hardness, toughness, strength, corrosion and abrasion resistance, etc.) by making changes in the atomic arrangement of the material.

In general, it is made by annealing metals at a certain temperature to bring their structures to the desired phase. The metal is then quenched and the granules are trapped at room temperature into a phase which is not a thermodynamically equilibrium phase. This phase is generally a phase in which the material exhibits superior mechanical properties. Although the theory of heat treatment is not well known, its practice was known and applied well before the industrial era. For example, it is a simple heat treatment for blacksmiths to cool down by sinking them into water after beating them to secure them. Similar applications; sharpness, hardness, abrasion resistance has been required in some other metal goods. Heat treatment is performed in vacuum, atmosphere controlled furnaces, induction flame surface hardening machines, fluidized beds and salt baths.