Casting has a variety of classification methods: according to their different use of metal materials, divided into cast steel, cast iron, cast copper pieces, cast aluminum, cast pieces of magnesium, cast zinc, cast titanium and so on. And each type of casting can be further divided into different types according to their chemical composition or metallographic organization. Such as cast iron can be divided into gray cast iron, ductile iron, vermicular graphite cast iron, malleable cast iron, alloy cast iron, etc .; according to the different molding methods, casting can be divided into ordinary sand casting, metal casting, , Centrifugal castings, continuous castings, investment casting, ceramic castings, electroslag remelting castings, bimetallic castings and so on. Which is the largest application of ordinary sand casting, accounting for about 80% of all castings. The aluminum, magnesium, zinc and other non-ferrous metal castings, mostly die castings.