It has excellent properties such as small specific gravity, high strength per unit weight and high chemical stability, which makes Al-Mg alloy and its magnesium alloy die castings popular, and the metal magnesium industry develops rapidly. Magnesium alloy used in automobile industry has the advantages of high strength, heat resistance, wear resistance and light weight, which makes it gradually replace plastic products and steel parts with large specific gravity in automobile industry, mainly replacing the original engine, steering wheel, seat base and so on. For example, the "Polaris V-8" engine of American General Motors Company has 65,438+05 pounds (6.8 kilograms) of magnesium die castings, and this engine is assembled on Cadillac. In the mid-1990s, the company produced 25,000 ~ 30,000 such cars every year and needed magnesium. The annual output of general motors in the United States has remained above 9 million, and that of Toyota in Japan has also remained above 9 million.