Pouring temperature of lost foam casting for bridge support

Pouring temperature is a key factor affecting the quality of EPC Castings. If the pouring temperature is too high, the body shrinkage and gas content of molten metal will be increased, and the casting defects such as shrinkage cavity, shrinkage porosity and air hole will be easily caused; if the pouring temperature is too low, the metal filling ability will be poor, and the casting will easily produce cold shut and insufficient pouring.

Because the pyrolysis and gasification of foam pattern is endothermic reaction, the heat of molten metal needs to be consumed, so the pouring temperature of lost foam casting is higher than that of casting cavity casting. At the same time, higher pouring temperature can improve the filling ability of molten metal, which is conducive to the discharge of pyrolysis products and reduce casting defects such as slag inclusion and carburization.

However, when the casting temperature reaches a certain value, increasing the pouring temperature will increase the air gap pressure between the metal liquid and the foam pattern, and then reduce the filling ability, partially or completely offset the beneficial effect of increasing superheat on the filling ability. According to the production experience, the pouring temperature of EPC cast steel is generally 50 ℃ ~ 80 ℃ higher than that of sand casting.

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