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Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand—known as casting sand—as the mold material. The term "sand casting" can also refer to an object produced via the sand casting process. Sand castings are produced in specialized factories called foundries. In 2003, over 60% of all metal ...
Ablation casting is a sand casting process that uses water to wash away the mold while the metal solidifies. This process produces castings with high mechanical properties, reduced defects, and a fine microstructure. Here are some steps in the ablation casting process:
A molding sand mixture, usually green sand or bentonite, is blown into a rectangular steel chamber using compressed air. The molding sand is then squeezed between two patterns, which are on the two ends of the chamber. After squeezing, one of the chamber plates swings open and the opposite plate pushes the finished mold onto a conveyor.
In the simplest sand casting procedure, the drag is placed upside down on a board, around a pattern of the part to be cast. The pattern is a model of the desired casting. Talcum powder is often dusted over the pattern to aid in the removal of the pattern. Sand is sifted over the pattern until the model is covered by a few inches of sand.
Sand casting is one of the earliest forms of casting practiced due to the simplicity of materials involved. It still remains one of the cheapest ways to cast metal because of that same simplicity. Other methods of casting, such as those using shell molds , boast higher quality of surface finish but have a higher cost.
For example, a cold-box sand casting core binder is sodium silicate which hardens on exposure to carbon dioxide. [5] Special binders are used in air-set sands to produce core at room temperature. These sands do not require a gas catalyst because organic binders and a curing catalyst are mixed together in the sand which initiates the curing process.
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Evaporative-pattern casting is a type of casting process that uses a pattern made from a material that will evaporate when the molten metal is poured into the molding cavity. The most common evaporative-pattern material used is polystyrene foam. [1] The two major evaporative-pattern casting processes are: [1] Lost-foam casting; Full-mold casting