The heat treatment of mold steel is a process to heat, heat and cool the metal material in a solid state to change its internal structure and obtain the required performance.

The heat treatment of mold steel is divided into preliminary heat treatment and final heat treatment. Preliminary heat treatment includes annealing, normalizing, quenching and tempering, etc. The function of normalizing and annealing is to eliminate the internal stress of the hot processed blank, refine the grain, adjust the structure, improve the machinability, and prepare the organization for the subsequent heat treatment process.

Quenching and tempering is to improve the comprehensive mechanical properties of the parts and prepare for the final heat treatment. The process position is generally arranged after the blank production is completed and before cutting; after rough machining and before finishing. The heat treatment of the final die steel includes various quenching and tempering and chemical heat treatment. After this heat treatment, the hardness of the parts is very high. Except for grinding, it is generally not suitable for other cutting processes. The process position is generally arranged after semi-finishing and before grinding (finishing). For high-precision parts, in order to eliminate the stress caused by machining and reduce the deformation of the parts, stress relief annealing can be arranged after rough machining.

The purpose of die steel heat treatment can not only improve the processing performance of the material, but more importantly, it can give full play to the potential of the die steel material, improve the performance, save costs, and extend the service life of the workpiece.

According to different heating and cooling methods, the common heat treatments are classified as follows:

① Overall heat treatment: annealing, normalizing, quenching, tempering, etc.

②Surface heat treatment: surface quenching, physical vapor deposition and chemical vapor deposition, etc.

③Chemical heat treatment: carburizing, nitriding, carbonitriding, etc.