The density of cast aluminum alloy is lower than that of cast iron and cast steel, while the specific strength is higher. Therefore, using aluminum alloy castings under the same load can reduce the weight of the structure. Therefore, aluminum alloy castings are widely used in aviation industry, power machinery and transportation machinery manufacturing. Aluminum alloy has good surface gloss and good corrosion resistance in atmosphere and fresh water, so it is widely used in the manufacture of civil utensils. Pure aluminum has good corrosion resistance in oxidizing acid media such as nitric acid and acetic acid, so aluminum castings also have certain applications in chemical industry. Pure aluminum and aluminum alloys have good thermal conductivity. Heat exchange devices used in chemical production and parts requiring good thermal conductivity in power machinery, such as cylinder heads and pistons of internal combustion engines, are also suitable for manufacturing with aluminum alloys.
Aluminum alloy has good casting properties. Due to the low melting point (the melting point of pure aluminum is 660.230c, and the pouring temperature of aluminum alloy is generally about 730 ~ 750oc), casting methods such as metal mold and pressure casting can be widely used to improve the internal quality, dimensional accuracy, surface finish and production efficiency of castings. Due to the large solidification latent heat of aluminum alloy, under the condition of the same weight, the solidification process time of liquid aluminum is much longer than that of cast steel and cast iron, and the discharge fluidity is good, which is conducive to casting thin-walled and complex castings.