The performance requirements of sand cast iron castings include the following aspects

Sand is the main molding material of iron castings and has an important influence on the quality of iron castings. The performance requirements of sand cast iron castings include the following aspects:

1. Chemical composition of molding sand for cast iron platforms: Quartz sand is generally used as a raw material for the production of gray cast iron platforms, and the mass fraction of silica is 90%-95%.

2. Granularity and shape of cast iron platform sand: In rivet platform castings, the decomposition of the rivet platform model during the pouring process mainly depends on the coating and molding sand. For clean molding sand, the permeability depends on the size of the sand particles, generally between 30-70 sieves. Round sand is generally used because of its good fluidity, compactness and high permeability.

3. Moisture of casting sand of cast iron platform: The moisture in casting sand is the root cause of many casting defects of cast iron platform. The use of dry sand that does not contain moisture also means that a large amount of heat required for gas moisture can be reduced, which is beneficial to the gasification conditions of cast iron platform models and ensures the quality of castings. The ideal molding sand has no moisture, but due to atmospheric humidity and condensation, it is inevitable that there will be trace moisture, so the moisture content of cast iron platform molding sand should be less than 1%.

4. The mud content of the casting sand: Due to the thermal action of the high-temperature molten metal, some components in the casting sand gasify to generate a large amount of gas, and at the same time form a high pressure. The mud content of the molding sand should be less than 1%-3%, and the sand can generally be washed with water.

5. Sand temperature of cast iron platform: The thermal stability of cast iron platform is poor. If the temperature of the molding sand is too high, it will soften the riveted platform model and increase the possible deformation of the model. In order to prevent the model from being deformed by heat, the temperature of the molding sand should be strictly controlled, generally not exceeding 60 °C.