Overview of valve casting in China

Casting is the process of pouring liquid metal into a mold cavity which is suitable for the shape of the part, and then solidifying to obtain the part with certain shape, dimension and surface quality.

Casting has a long history, about 3000 BC, mankind has cast a variety of exquisite bronzes. But for thousands of years, it was made of clay, sand and other natural materials by hand. The output of castings is very small. With the development of industrial revolution, the increase of mechanization and the increase of demand for castings, the pneumatic machine and artificial synthetic molding clay sand process were used in the 1930s. With the development of the times, all kinds of modeling methods come into being. For example, cement sand mold appeared in 1933, cement flow sand mold appeared in 1967, cooling resin coated sand mold appeared in 1944, hot resin coated sand mold appeared in 1955, furan resin self hardening sand mold appeared in 1958, CO2 hardened water glass sand mold appeared in 1947, and water glass (organic resin water glass) technology of organic hardener appeared in 1968. In recent years, new methods of mold making by physical means, such as magnetic shot molding, vacuum sealing molding, film loss molding, etc. Casting is widely used in various sectors of national economy, such as machinery manufacturing, mine metallurgy, transportation, petrochemical general equipment, agricultural machinery, energy power, light industry and textile, civil engineering, power electronics, aerospace, international military industry, etc., due to the advantages of selecting casting alloys with various compositions and properties, small processing capital investment, large process flexibility and short production cycle, It is the foundation of modern large machinery industry.

Casting has a long history in China, but the casting technology has been stagnant for a long time. Since the reform and opening up, China’s casting technology has made great progress, which is manifested in three aspects: the degree of mechanization and automation of molding and core making has been significantly improved; self hardening chemical molding sand has replaced dry clay sand and oil sand; the casting technology has changed from experience to science, such as: Computer simulation design. This series of reforms have played an important role in improving production efficiency, reducing labor intensity, improving production environment, improving internal and external quality of castings, and saving raw materials and energy.