Sand casting refers to the casting method of producing chemical pump castings in sand molds. Steel, iron, and most non-ferrous alloy castings can be obtained by sand casting method. Due to the low cost and easy availability of molding materials used in sand casting, as well as the simplicity of mold manufacturing, it has been a basic process in casting production for a long time and can adapt to single piece production, batch production, and mass production of castings.

The basic raw materials for manufacturing sand molds are casting sand and molding sand binders. The commonly used casting sand is siliceous sand. When the high-temperature performance of silica sand cannot meet the requirements for use, special sand such as quartz sand, chromite iron ore sand, and corundum sand should be used. To ensure that the sand mold and core produced have a certain strength and do not deform or be damaged during transportation, molding, and pouring of liquid metal, it is generally necessary to add sand binder in casting to bond loose sand particles together to form sand. The most widely used sand binder is clay, and various dry or semi dry oils, water-soluble silicates or phosphates, and various synthetic resins can also be used as sand binders. The external sand molds used in sand casting are divided into three types: clay wet sand mold, clay thousand sand mold, and chemically hardened sand mold based on the type of binder used in the sand and the method of establishing strength.