Metal heat treatment is an important process in steel plate manufacturing, one compared with other processing, heat treatment generally does not change the overall shape of the workpiece and the chemical composition, but by changing the internal microstructure of the workpiece, or to change the chemical composition of surface to give or improve parts of the performance. Its characteristics are to improve the intrinsic quality of the workpiece, which is not generally the naked eye can see. To make the metal parts with the required mechanical properties, physical and chemical properties, in addition to a reasonable selection of materials and a variety of forming processes, the heat treatment process is often essential. Steel is the most widely used in machinery industry of materials, steel complex microstructure can be controlled by heat treatment, steel heat treatment of metal so the heat of the main content. In addition, aluminum, copper, magnesium, titanium and its alloys can also be changed by heat treatment the mechanical, physical and chemical properties, to achieve different performance.

The most common heat treatment methods are as follow: