The mechanical properties of cast steel are higher than cast iron, but the casting properties are worse than cast iron. Because the melting point of cast steel is high, the liquid steel is easy to oxidized, the fluidity of molten steel is poor, and the shrinkage is large, the shrinkage rate of the body is 10 ~ 14%, and the linear shrinkage is 1.8 ~ 2.5%. In order to prevent defects such as insufficient pouring, cold isolation, shrinkage and porosity, cracks and sand, steel casting is customized, and more complex process measures must be taken than cast iron:
1, due to the poor fluidity of the liquid steel, in order to prevent the steel casting cold insulation and insufficient pouring, the wall thickness of the steel casting can not be less than 8mm; The structure of the pouring system is simple, and the section size is larger than that of cast iron. Use dry casting or hot casting; Appropriately increase the pouring temperature, generally 1520° ~ 1600 ° C, because the pouring temperature is high, the superheat of molten steel is large, the liquid time is long, and the fluidity can be improved. But too high pouring temperature will cause coarse grain, hot cracking, porosity and sand and other defects. Therefore, generally small, thin-walled and complex castings, the pouring temperature is about the melting point temperature of steel +150℃; Customized steel casting, large, thick wall casting casting temperature is about 100℃ higher than its melting point.
2, because the shrinkage of cast steel is much more than that of cast iron, in order to prevent the casting of shrinkage holes, shrinkage defects, most of the measures such as riser and cold iron and subsidies are used in the casting process to achieve sequential solidification. In addition, in order to prevent the production of shrinkage holes, porosity, porosity and cracks in the steel casting, the steel casting should be customized to make its wall thickness uniform, avoid sharp corners and right Angle structures, add sawdust in the mold sand, add coke in the core, and use hollow core and oil sand core to improve the yield and permeability of the sand or core.
Changshu Hongqiao Cast Steel Co., Ltd. mainly produces various specifications of carbon steel, high, middle and low alloy steel, stainless steel, heat-resistant steel, high manganese steel, high chromium cast iron. For petroleum, chemical industry, metallurgy, mining machinery, coal mining machinery, wind power, nuclear power, Marine and other industries to provide high-quality steel casting, and export abroad. Changshu Hongqiao Cast Steel Co., Ltd. cast steel custom