Process characteristics of stainless steel precision casting_Jiangxi Ruiguan Precision Casting Co., Ltd. | Stainless Steel Electronic Hardware | Lock Casting

Process characteristics of stainless steel precision casting

Date：

2022-06-24

Process characteristics of stainless steel precision casting

Stainless steel has higher mechanical properties than cast iron for precision casting, but not as good as cast iron. Due to the high melting point of stainless steel precision casting, the fluidity of molten steel is poor, the molten steel is easy to oxidize, and the shrinkage is large. The linear shrinkage is about 1.8-2.5%, and the volume shrinkage rate is about 10-14%. In order to prevent defects such as cold insulation, insufficient pouring, shrinkage porosity, shrinkage cavities, sand sticking and cracks in steel castings, more complex technological measures than cast iron must be taken:

1) The structure of the gating system is simple and the cross-sectional size is larger than that of cast iron. Generally, dry casting or hot casting is used; due to the poor fluidity of molten steel, in order to prevent cold insulation and insufficient pouring of steel castings, the The wall thickness should not be less than 8mm; increase the pouring temperature appropriately, because the pouring temperature is high, the superheat of the molten steel is large, and the fluidity can be improved for a long time in the liquid state. However, if the pouring temperature is too high, it will cause defects such as thermal cracking, coarse grains, sticky sand and pores. Therefore, the pouring temperature of general large and thick-walled castings is about 100°C higher than the melting point; for thin-walled, small and complex-shaped castings, the pouring temperature is about the melting point temperature of steel + 150°C.

2) Because the shrinkage rate of stainless steel is much larger than that of cast iron, in order to prevent shrinkage porosity and shrinkage cavity defects in castings, measures such as cold iron, risers and subsidies are mostly used in the casting process to achieve sequential solidification.

In addition, in order to prevent shrinkage porosity, shrinkage cavities, cracks and porosity defects in stainless steel castings, it should avoid sharp and right-angle structures, uniform wall thickness, add coke in the core, add sawdust in the casting sand, and use Oil sand cores and hollow cores are used to improve the permeability and concession of cores or sand molds.