Today, the term "lightweight" has evolved from a term in the automotive industry to a high-frequency vocabulary in media news. In "Made in China 2025", lightweight has also been regarded as an important direction for the development of the automotive industry. To put it simply, light weight is to reduce the weight of the vehicle as much as possible on the premise of ensuring the strength and safety performance of the car, thereby improving the power of the car, reducing fuel consumption, and reducing exhaust pollution. In recent years, due to the increasingly strict requirements for environmental protection and energy saving, automobile lightweight has become an unstoppable trend in the development of the world's automobiles. According to the report of the European Aluminum Association, for every 100kg of automobile quality reduction, 0.6L of fuel can be saved per 100km, and CO2800-900g can be reduced. The density of aluminum is only 1/3 of that of steel, and it has good plasticity and recycling. It is an ideal lightweight material for automobiles. During the first and second oil crisis in the 1970s, in the face of rising oil prices, automakers around the world tried to use aluminum alloys to manufacture previously steel radiators, cylinder heads, bumpers and other components to improve Fuel efficiency. Since then, the proportion of aluminum alloys in automobiles has continued to increase. Research data released by the famous consulting company Ducker Worldwide (Ducker Worldwide) shows that the average aluminum consumption in Europe has tripled since 1990, from 50kg to the current 151kg, and will increase to 196kg in 2025.

At present, the lightening trend of automobiles is becoming more and more intense, and aluminum alloys are widely used in wheels, engines, radiators, and oil pipes. The body mass accounts for about 40% of the total mass of the car. For the weight reduction of the entire vehicle, the weight reduction of the body plays an important role. According to the EuroCarBody 2016 data, the application rate of aluminum alloys has reached more than half of the quality of body-in-white (ie, welded but unpainted bodies) of some high-end models. For example, the application rate of Aston Martin DB11 aluminum alloy is as high as 86.1%, the second-generation Honda NSX (Acura NSX) reaches 79.0%, and the fifth-generation Land Rover Discovery (Land Rover Discovery) reaches 62.9%. However, the use of aluminum alloys on the body of ordinary models is still relatively small. Data from the well-known consulting company Ducker Worldwide shows that the penetration rate of aluminum alloy plates in automobile bodies was only 4% in 2015. Today, all-aluminum body manufacturing is still a technology at the tip of the pyramid, which is only applicable to some high-end models. Lightweight body is an important research topic in the current lightweight development of auto manufacturers.