Precision casting manufacturers briefly describe the causes of pores

Published on:

2020-12-23

Porosity refers to the smooth hole defects in individual positions of precision castings. It is one of the common precision casting defects. This situation is usually found after machining. The following precision casting manufacturers combine years of workshop production experience to provide you with this problem Describe the reason, hope it will be helpful to your future operation.
　　 1. Reasons for formation:
　　 1). Because of the shell-making process or shell-shaped materials, the gas permeability of the shell is too poor, and the gas in the cavity is difficult to discharge, and it enters the molten metal to form pores.
　　2). Casting pores caused by the failure of the air drawn into the molten steel during pouring to be discharged.
　　3). In most cases, pores appear mainly because the precision casting mold shell is not sufficiently roasted. When the molten steel is poured, a large amount of gas is generated in the mold shell and cannot be discharged smoothly, and then invades into the molten metal to form pores.
Precision casting manufacturers briefly describe the causes of pores

　　 2. Prevention methods:
　　1). When the precision casting conditions permit, set up vent holes at the height of the casting with complex structure.
　　2). When designing the gating system, fully consider the exhaust gas demand of the shell.
　　3). When dewaxing, the wax should be completely eliminated.
　　4). The baking temperature and time of the mold shell should be reasonable, and the holding time should be sufficient.
　　5). Reduce the distance from the ladle nozzle to the sprue cup appropriately, and the pouring speed should be uniform to ensure that the molten steel fills the cavity smoothly, and the air in the molten steel is as little as possible so that the gas in the cavity and the molten steel can be discharged smoothly.
　　 Ruifeng Metal is a professional precision casting manufacturer, mainly engaged in the research and development, production and sales of stainless steel valves, stainless steel flanged ball valves, stainless steel PPR valves, stainless steel pipe fittings and precision castings. If you have relevant product requirements, please feel free to contact us.
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