Stainless steel castings, as the name implies, are the general term for steel castings made from various stainless steel materials. It has a wide range of applications. The key point is its casting process. Here is a brief introduction to the characteristics of the casting process of the product:
1. Since the shrinkage of cast steel greatly exceeds that of cast iron, in order to prevent castings from shrinking holes and shrinking defects, most measures such as riser sum, cold iron and subsidies are adopted in the casting process to achieve sequential solidification.
2. The melting point of cast steel is high
1. Correspondingly, its pouring temperature is also high. At high temperatures, the molten steel interacts with the mold material, which is easy to produce sticky sand defects. Therefore, artificial quartz sand with high refractoriness should be used as the mold.
2. Brush the coating made of quartz powder or zirconium sand powder on the surface of the casting mold. In order to reduce the gas source, improve the fluidity of the molten steel and the strength of the casting mold, most of the steel castings are cast with dry or quick-drying molds. CO2 hardened water glass sand mold.
3. Poor mobility of molten steel
1. Properly increase the pouring temperature, generally 1520° ~ 1600°C, because the pouring temperature is high, the superheat of the molten steel is large, the liquid stays for a long time, and the fluidity can be changed.
2. Therefore, dry casting or hot casting is adopted. In order to prevent the cold separation and insufficient pouring of the steel castings, the wall thickness of the steel castings should not be less than 8mm. The structure of the pouring system strives to be simple, and the cross-sectional size is larger than that of cast iron.
3. Excessive pouring temperature will cause defects such as coarse grains, hot cracks, porosity and sticky sand. Therefore, the casting temperature of generally small, thin-walled and complex-shaped castings is about the melting point temperature of steel +150℃. The pouring temperature of large, thick-walled castings is about 100°C higher than its melting point.
4. In order to prevent shrinkage, shrinkage, porosity and crack defects, the wall thickness should be uniform, sharp and right angle structures should be avoided, sawdust should be added to the molding sand, coke should be added to the core, and the hollow type should be used. Core and oil sand core to change the yield and breathability of sand mold or core.