Metal heat treatment is one of the important processes in mechanical manufacturing, compared with other processing processes, heat treatment generally does not change the shape of the workpiece and the overall chemical composition, but by changing the microstructure of the workpiece, or change the chemical composition of the workpiece surface, give or improve the performance of the workpiece.Its characteristic is to improve the inherent quality of the workpiece, which is generally not visible to the naked eye.

In order to make the metal workpiece with the required mechanical properties, physical properties and chemical properties, in addition to the rational selection of materials and various forming processes, heat treatment process is often essential.

The mechanical, physical and chemical properties of aluminum, copper, magnesium, titanium and their alloys can be changed by heat treatment to obtain different performance.

Heat treatment process generally includes heating, heat preservation, cooling three processes, sometimes only heating and cooling two processes.These processes are interlinked and cannot be stopped.