Cast steel coated sand is a new type of coated sand product with excellent high-temperature performance and comprehensive casting performance. Cast steel coated sand has the characteristics of high strength, good flowability, fast solidification speed, high SiO2 content, strong high-temperature resistance, low gas generation, and good flowability. It is a widely used molding material for steel castings such as valve shells, buffer joints, steel shafts, engineering excavators, and container corners.

During the production process of cast steel coated sand, the pouring temperature of the steel liquid is relatively high, so the requirements for fire resistance of the raw sand are also high. Usually, the SiO content of the raw sand needs to be greater than 98%, and special attention should be paid to the particle size and distribution of the raw sand. The mature experience in selecting raw sand in China mostly draws on the cast steel coated sand produced by Longkou Green Sand Economic and Trade Co., Ltd., and uses special artificial sand with a fire resistance of up to 1900-2000 ℃, which not only has good particle shape, but also, Effectively preventing chemical sand sticking, with a small angular coefficient and moderate particle size, it can make the sand particles closer to a circular shape. With the same amount of resin added, the resin film is thicker, which is beneficial for improving the strength of the sand core.

The main component of quartz sand minerals in cast steel coated sand during phase transformation treatment is quartz, followed by feldspar, a small amount of mica, and iron oxides. Due to the low hardness and melting point of feldspar and mica, while quartz has a high hardness and expands greatly when heated, phase change treatment is required for quartz sand in the production process of cast steel coated sand to reduce the expansion of the original sand and reduce the content of feldspar and mica, ultimately improving the fire resistance of the original sand. Moreover, the surface of quartz sand after phase change treatment has a clean acid consumption value, effectively reducing the amount of resin and curing agent used.