The four basic processes in die casting aluminum industry are annealing, normalizing, quenching and tempering, which are called "four fires" in die casting. In the process of die casting, quenching and tempering are closely related, and both are indispensable. It is understood that annealing is to heat the workpiece. When the workpiece is heated to a suitable temperature, according to the different materials selected, the die casting is slowly cooled and the internal structure of the metal is close to balance. Normalization is to heat the workpiece to a suitable temperature and then cool it in the air, which is mainly used to improve the cutting function of materials, and can also be used as the end of die casting for some parts with low requirements. Quenching is to heat and insulate the workpiece, and then quickly cool it in inorganic salt solutions such as water and sodium hydroxide. After this process, the steel parts produced will become hard and brittle at the same time. In order to reduce the brittleness of steel parts, the quenched steel parts can be kept at a temperature below 650 degrees Celsius and higher than normal temperature for a long time, and then cooled, which is called tempering. Application of Aluminum Die Casting Aluminum materials and aluminum alloys have good fluidity and plasticity, and can manufacture various die castings with complex shapes and great difficulties. The castings made of aluminum alloy and metallic aluminum have high precision and high surface finish, which greatly reduces the processing capacity of castings, greatly reduces the labor intensity and saves electricity and metallic materials. Because of its high internal and external quality, aluminum die-casting parts are widely used in automobile manufacturing, internal combustion engine production, motorcycle manufacturing, motor manufacturing, transmission machinery manufacturing, precision instruments, landscaping, electric power construction and other industries, and become the new favorite of die-casting industry.