Castings are classified into steel castings, cast iron castings, cast copper castings, cast aluminum castings, cast magnesium castings, cast zinc castings and cast titanium castings. Each type of casting can be further divided into different types according to its chemical composition or metallographic structure. For example, cast iron can be divided into gray cast iron, nodular cast iron, vermicular cast iron, malleable cast iron, alloy cast iron, etc.

According to different casting methods, castings can be divided into ordinary sand casting, metal casting, die-casting, centrifugal casting, continuous casting, investment casting, ceramic casting, electroslag recasting casting, bimetallic casting, etc. Among them, ordinary sand casting is the most widely used, accounting for about 80% of the total casting output. And aluminum, magnesium, zinc and other non-ferrous metal castings, mostly die casting.

Castings are metal molding objects obtained by various casting methods, that is, molten liquid metal is injected into prepared casting molds by pouring, injection, suction or other casting methods, and the objects with certain shapes, sizes and properties are obtained after cooling and polishing.