Gravity casting aluminum production
Gravity casting of aluminum alloy generally refers to the method of complete mold filling and solidification of liquid aluminum alloy under the action of gravity, including sand casting, gravity casting, investment casting, gypsum casting, etc. in a narrow sense, it refers to metal mold casting, that is, the casting process of aluminum alloy casting is to pour the liquid aluminum alloy into the steel mold, take it out after cooling and forming, so it is also called gravity casting aluminum, or steel mold Casting, steel mold casting.
The process can produce products with high dimensional accuracy, beautiful appearance, good compactness and high strength, especially for T6 heat treatment, so that the aluminum castings have high strength, hardness and elongation, and can be used in some application fields with high mechanical property requirements, such as aerospace, etc. aluminum hub in automobile, railway, medical and other industries is a typical application of automobile. Many friends think it's die cast. It is not true. The aluminum wheel hubs all over the world are made by gravity casting or low-pressure casting. It cannot be made by die casting. The die-casting aluminum hub is filled with a lot of gas, forming a lot of small bubbles. On the one hand, it reduces the mechanical properties, on the other hand, it is guided by the existence of bubbles, so T6 heat treatment cannot be carried out, and the mechanical properties cannot be further improved. The aluminum alloy parts produced by aluminum alloy die casting process need high iron content, which determines the elongation of gravity casting aluminum parts. If the iron content is high, the elongation of aluminum castings is low, which is usually called brittleness and poor impact resistance. Therefore, aluminum alloy castings with high strength, high safety and impact resistance, such as aluminum hub, cannot be produced by aluminum alloy die casting process.