铝合金铸造工艺性能（Aluminum alloy, casting process, property）.doc

铝合金铸造工艺性能（Aluminum alloy, casting process, property） 1 、 aluminum alloy casting process performance The casting process performance of aluminum alloys is usually understood as the synthesis of those which are most outstanding in the process of casting, crystallization and cooling. Fluidity, shrinkage, air tightness, casting stress and aspiration. The properties of aluminum alloys depend on the composition of the alloy, but also on the casting factors, the alloy heating temperature, the complexity of the casting, the gating system and the shape of the gate. (1) liquidity Fluidity is the ability to fill a mold with an alloy liquid. The size of the fluidity determines whether the alloy can be cast with complex castings. In aluminum alloy, the fluidity of eutectic alloy is the best. Many factors influence the liquidity, is the main component, temperature and alloy liquid metal oxide, metal compounds and other pollutants of solid particles, but the fundamental external factors for pouring temperature and pouring pressure (commonly known as the pouring head height). (2) contractility; Shrinkage is one of the main characteristics of cast aluminum alloy. Generally speaking, the alloy is poured from liquid to solidification until it reaches the room temperature. It is divided into three stages, namely liquid contraction, solidification contraction and solid contraction. The shrinkage of alloy has a decisive influence on the quality of casting. It affects the size of shrinkage hole, stress, crack formation and size change of casting. Generally, shrinkage of casting is divided into body contraction and linear contraction. In actual production, linear shrinkage is used to measure the shrinkage of alloy. The shrinkage of aluminum alloys is usually expressed in terms of percentage, called shrinkage. Body contraction Body contraction consists of fluid contraction and coagulation contraction. The casting alloy liquid from pouring to solidification, in the final solidification place