Chrome ore sand, also known as chromite sand, is a special sand for foundry. It is a natural spinel mainly made of chromite, which is crushed, ground, and sieved into a specified particle size, suitable for modeling (core making) sand. Chrome ore is mainly used for sand on the surface of large steel castings to prevent adhesion of the surface of the castings. So what are the applications of chrome ore in foundry?
Casting chrome ore is a product processed by natural chromite ore through crushing and screening processes, and its main chemical composition is Cr2O3. This kind of sand has the advantages of stable volume and high thermal conductivity. It not only has good anti-alkali slag function when it comes into contact with molten metal, but also does not chemically react with iron oxide. It also has the characteristics of solid phase sintering, which can prevent the penetration of molten metal. , To avoid the formation of sand defects.
2. During the molten metal casting process, the chromium ore itself undergoes solid phase sintering, which prevents the penetration of molten metal, thereby preventing mechanical sand sticking;
3. The thermal conductivity of chromium ore sand is several times greater than that of silica sand, which can increase the cooling rate of castings. Therefore, chromium ore sand can play the role of external chilled iron in practical applications;
The harmful impurity in chromium ore is carbonate. When it comes into contact with high-temperature metals, it decomposes CO2, which is easy to cause pores in the casting; usually, chromium ore containing carbonate is roasted at high temperature to decompose the carbonate. The effect of the particle size of chrome ore on its refractoriness The particle size of chrome ore can significantly affect its refractoriness.
The surface of the sand mold and core is usually sprayed with a certain thickness of paint, so that the surface finish of the casting is almost unaffected. There are also some special situations such as: some small water pump industries, considering economic factors, replace zircon sand with chromium ore.