The technological properties of aluminum alloy castings are usually understood as the most outstanding combination of those properties during mold filling, crystallization and cooling. Fluidity, shrinkage, air tightness, casting stress, air suction. These characteristics of aluminum alloy depend on the composition of the alloy, but they are also related to casting factors, alloy heating temperature, mold complexity, gating and riser system, gate shape and so on. (1) fluidity refers to the ability of alloy liquid to fill the mold. Fluidity determines whether the alloy can cast complex castings. Among aluminum alloys, * * * crystal alloy has the best fluidity. There are many factors that affect the fluidity, mainly the composition, temperature and solid particles of pollutants such as metal oxides and metal compounds in the alloy liquid, but the external fundamental factors are pouring temperature and pouring pressure (commonly known as pouring head). In actual production, when the alloy has been determined, in addition to strengthening the smelting process (refining and slag removal), it is necessary to improve the casting process (sand mold permeability, metal mold exhaust and temperature) to increase the pouring temperature without affecting the casting quality, so as to ensure the fluidity of the alloy. (2) Shrinkage is one of the main characteristics of cast aluminum alloy. Generally speaking, from liquid casting to solidification cooling to room temperature, the alloy can be divided into three stages, namely liquid shrinkage, solidification shrinkage and solid shrinkage. The shrinkage of alloy has a decisive influence on the quality of castings, which affects the shrinkage cavity size, stress generation, crack formation and size change of castings. Usually, the shrinkage of castings is divided into volume shrinkage and linear shrinkage, and the linear shrinkage is generally used to measure the shrinkage of alloys in actual production. Mold preparation (container for making liquid metal into solid castings) can be divided into sand mold, metal mold, ceramic mold, clay mold, graphite mold, etc. According to the use times, it can be divided into disposable mold, semi-permanent mold and permanent mold. Mold quality is the main factor affecting the quality of castings;

Melting and pouring of casting metal, casting metal (casting alloy) mainly includes all kinds of cast iron, cast steel and casting non-ferrous metals and alloys;

Casting processing and inspection, casting processing includes removing foreign bodies from the core and surface of the casting, cutting off the riser, shoveling off burrs, caulking and other protrusions, heat treatment, shaping, rust prevention and rough machining. The casting process can be divided into three basic parts, namely, casting metal preparation, mold preparation and casting treatment. Casting metal refers to the metal material used for casting in casting production, which is an alloy composed of a metal element as the main component and other metal or nonmetal elements, and is customarily called casting alloy.