1. Because ofPrecision cast steelThe shrinkage of cast iron is much higher than that of cast iron. In order to prevent shrinkage cavities and shrinkage defects in castings, most of the casting processes adopt measures such as risers, chilled iron, and subsidies to achieve sequential solidification.

In order to prevent the occurrence of shrinkage holes, shrinkage porosity, pores and cracks in stainless steel castings, the wall thickness should be uniform, sharp corners and right-angle structures should be avoided, sawdust is added to the molding sand, coke is added to the core, and hollow type is used. Cores and oil sand cores, etc. to improve the retreatability and air permeability of sand molds or cores.

2. Due to the poor fluidity of molten steel, in order to prevent cold barriers and insufficient pouring of steel castings, the wall thickness of steel castings should not be less than 8mm; use dry casting or hot casting; appropriately increase the pouring temperature, generally 1520°~ 1600°C, because the pouring temperature is high, the molten steel has a high degree of overheating, and it stays liquid for a long time, and the fluidity can be improved. However, if the pouring temperature is too high, it will cause defects such as coarse grains, thermal cracks, pores and sand sticking. Therefore, generally small, thin-walled and complex-shapedLost wax castingThe casting temperature is about the melting point temperature of steel +150°C; the structure of the casting system is simple and the section size is larger than that of cast iron; the casting temperature of large, thick-walled castings is about 100°C higher than its melting point.