How to prevent casting grade chromite sand from sticking to sand
1. Chromite sand is not easily wetted by high-temperature molten steel. The transparency of the molten steel is not easy to penetrate into the sand particles, and it is not easy to form mechanical sand sticking. Chromite sand has good resistance to alkaline slag and does not react with iron oxide, so it can also avoid the defects of chemical sand sticking.
2. The thermal conductivity and heat storage coefficient of the cathode iron ore are relatively large (several times larger than that of silica sand), so the cooling speed is fast, so that the metal on the surface of the casting is quickly cooled, and the low melting point generated during the next step of the metal liquid casting is generated At the same time, the material solidifies rapidly with the rapid cooling of the metal. Due to the much accelerated cooling rate, an amorphous glass phase is formed between the mold shell and the casting. This glass phase easily falls off from the surface of the casting. Therefore, it is easy to assemble the castings after sand cleaning. The surface finish of the castings after sand cleaning is high, and the defects of sand sticking to the surface are avoided.
3. Chromite sand has a high conductivity coefficient and heat storage coefficient, so it generates a chill on the high-temperature metal surface after casting. Its function is equivalent to an external cold iron, which strengthens the sequential flow of the catalyst metal and improves the production rate. Eliminates the formation of shrinkage cavities and porosity. The quenching process refines the crystal particles of the metal, improves the mechanical properties of the metal, and thereby improves the overall quality of the casting.