The mechanical properties of stainless steel precision casting are higher than that of cast iron, but its casting performance is lower than that of cast iron, which belongs to precision casting or precision casting. Its melting point is higher, the steel liquid is easy to oxidize, the liquid of steel water is poor, shrinkage is large, the stainless steel precision casting not only applies to various kinds, various alloy casting.
Process characteristics of stainless steel precision casting:
1, because of the stainless steel precision casting shrinkage considerably more than cast iron, to prevent casting shrinkage cavity, shrinkage defects, using riser and mostly on the casting process, cold iron and subsidies and other measures, in order to realize the solidification sequence.
To prevent stainless steel castings, shrinkage cavity, shrinkage, porosity and crack defects, should make its uniform thickness, avoid sharp corners and rectangular structure, sawdust are added into the mould with sand, add coke to the core, and the hollow core and sand core and so on to improve the sand mold or core of breathable and back down.
2. Due to the poor liquidity of the steel liquid, the wall thickness of the cast steel parts should not be less than 8mm to prevent the casting of steel castings from being cold and inadequate. Dry cast or hot cast; Properly increasing pouring temperature, average of 1520 ° ~ 1600 ℃, because of the high pouring temperature, liquid steel superheat, keep long liquid, liquid can be improved. However, the temperature is too high, which can cause the defects such as coarse grain, hot crack, stoma and sand. So generally small, thin wall and complex shape precision castings, the pouring temperature is about steel melting point temperature of + 150 ℃; The structure of the pouring system is simple and the section size is larger than that of cast iron. Large, thick wall castings pouring temperature about 100 ℃ higher than the melting point.