Aluminum alloy profiles have been widely used in aviation, aerospace, automobile, machinery manufacturing, shipbuilding, construction, decoration and chemical industry.With the rapid development of science and technology and industrial economy in recent years, the demand for welded structural parts of aluminum alloy is increasing, which makes the research on the weldability of aluminum alloy deeper.

The wide application of aluminum alloys has promoted the development of aluminum alloy welding technology, and the development of welding technology has expanded the application field of aluminum alloys. 

Therefore, the welding technology of aluminum alloys is becoming one of the hotspots of research. 

The density of pure aluminum is small, about 1/3 of iron, and the melting point is low (660 °C). Aluminum is a face-centered cubic structure, so it has a high plasticity (δ: 32~40%, ψ: 70~90%). It is easy to process, and can be made into various profiles and plates, with good corrosion resistance.But the strength of pure aluminum is very low, so it is not suitable for structural materials.Through long-term production practice and scientific experiments, people gradually strengthen aluminum by adding alloy elements and using heat treatment methods, which gives a series of aluminum alloys. 

The alloy formed by adding certain elements can have higher strength while maintaining the advantages of pure aluminum such as light weight. This makes its "specific strength" (the ratio of strength to specific weight σb/ρ) better than many alloy steels, making it an ideal structural material. It is widely used in machinery manufacturing, transport machinery, power machinery and aviation industry. 

The fuselage, skin and compressor of aircraft are often made of aluminum alloy to reduce the dead weight. 

The welding of aluminum alloy instead of steel plate material can reduce the structure weight by more than 50%.