Metal products. Aluminum alloy belongs to metal, and curtain rail invoicing belongs to metal products. In addition to the general characteristics of aluminum, aluminum alloy has some special characteristics because of the different types and quantities of alloying elements. The density of aluminum alloy is 2.63-2.85g/cm, which has high strength, specific strength close to that of high alloy steel, specific stiffness higher than that of steel, good castability and plasticity, good electrical and thermal conductivity, good corrosion resistance and weldability, and can be used as structural materials in aerospace field.