Aluminum alloy is the most widely used non-ferrous metal structural material in industry. It has been widely used in aviation, aerospace, automobile, machinery manufacturing, shipbuilding and chemical industry. With the rapid development of industrial economy, the demand for aluminum alloy welded structural parts is increasing day by day, which makes the research on aluminum alloy weldability deepen. At present, aluminum alloy is the most widely used alloy.

Automobile beam is a kind of automobile chassis structure, but now the automobile basically does not adopt the beam chassis design, only trucks and buses will adopt it. The girder of a large truck is a pair of parallel channel steel connected by beams. The auxiliary beam is a beam set above and close to the main beam, so as to evenly distribute the load on the main beam.