Gravity casting of aluminum alloy is a process of injecting aluminum liquid into the mold under the action of gravity of the earth. Gravity casting can be divided into sand casting, metal (steel) casting, lost foam casting and so on. The mould is made of heat-resistant alloy steel. The strength, size and appearance of aluminum castings are higher than those of other casting processes.
The gravity casting aluminum liquid is usually poured into the gate by hand. According to the self weight of the metal liquid, the mold cavity is filled, vented, cooled and opened to obtain the sample. The process flow is generally: aluminum smelting, casting filling, exhaust, cooling, opening, cleaning, heat treatment and processing. The features of aluminum alloy gravity casting parts are as follows:
1. The surface finish of the product is not high, and it is easy to produce pits after shot peening.
2. Aluminum casting has few air holes and can be heat treated.
3. The product has low density, slightly poor strength, but high elongation.
4. The die has low cost and long service life.
5. Low production efficiency increases production cost.
6. The technology of gravity casting aluminum is simple and not suitable for producing thin-walled parts.