Characteristics and classification of heat treatment process

Heat treatment is a kind of metal hot working technology which can heat, heat and cool the metal material in a certain medium, and control its performance by changing the metallographic structure on the surface or inside of the material.

China is a big energy consumer, and machinery manufacturing industry is a very important part of it. With the continuous development of heavy industries such as parts and components, machinery manufacturing and so on, heat treatment plays an important supporting role in the revitalization and development of machinery manufacturing industry, and the development of machinery manufacturing industry will certainly drive the rapid development of China's heat treatment industry, and provide broad development space for the development of heat treatment industry.

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

In order to make the metal parts have the required mechanical, physical and chemical properties, in addition to the reasonable selection of materials and various forming processes, heat treatment process is often essential. Steel is the most widely used material in mechanical industry. The microstructure of steel is complex and can be controlled by heat treatment, so the heat treatment of steel is the main content of metal heat treatment. In addition, aluminum, copper, magnesium, titanium and their alloys can also change their mechanical, physical and chemical properties through heat treatment to obtain different service properties.

Metal heat treatment process can be generally divided into three categories: overall heat treatment, surface heat treatment and chemical heat treatment. According to the different heating medium, heating temperature and cooling method, each category can be divided into several different heat treatment processes. Different heat treatment processes can be used for the same metal to obtain different structures and different properties.