For aluminum alloy welding, tooling in the form of point contact is used to reduce the contact area between the tooling and the workpiece. If the tooling is in surface contact with the workpiece, it will quickly take away the heat of the workpiece and accelerate the solidification of the molten pool, which is not conducive to the elimination of weld pores. The pressure of the tooling hydraulic system is controlled at 9～9.5 MPa. 　　

The pressure is too small to achieve the purpose of anti-deformation, but too much pressure will increase the restraint of the aluminum alloy structure. Due to the large linear expansion coefficient of aluminum alloy and poor high-temperature plasticity, large thermal stress is likely to occur during welding, which may cause cracks in the aluminum alloy structure. Aluminum alloy welding protection measures　　
1. Use mechanical or chemical methods to remove oxides on the groove and surrounding parts of the workpiece and the surface of the welding wire before welding; 　　
2. Use qualified shielding gas for protection during welding; 　　
3. In the gas welding, flux is used, and the oxide film on the surface of the molten pool is constantly picked up by the welding wire during the welding process.

The definition, properties and uses of cast aluminum alloy] The definition, properties and uses of cast aluminum alloy is to add appropriate amounts of other elements to industrial pure aluminum to make the essence of aluminum to meet the needs of industry and people’s lives. Various needs. Because of its small specific gravity, high specific strength, and good overall performance, it is widely used in the aviation industry, automobile manufacturing, power meters, tools, and civil vessel manufacturing. Cast aluminum alloy is a kind of aluminum alloy, which is mainly used to produce products with complex shapes and mass production. It mainly adopts aluminum alloy gravity casting, low pressure casting, sand casting and other processes for production. After casting, heat treatment can be carried out to increase the strength, hardness and elongation of the casting, which is a main method of aluminum alloy application.