METHOD FOR PREVENTING CARBURIZING INTO LOW CARBON CASTING PRODUCT IN CONSUMABLE PATTERN CASTING METHOD

摘要

PURPOSE:To prevent carburizing into a low carbon casting product by arranging a guide hole for molten metal communicated with a gate hole in a product pattern of lost foam pattern composed of foamed resin, etc., and increasing exhausting area of heat decomposed product with the molten metal. CONSTITUTION:The consumable pattern 3 composed of a runner 4, gate 5 and the product pattern 6 made of the foamed resin, etc., is set in a flask 1. Successively, unbonded molding sand 2 is packed into the flask 1 around the product pattern 6 while vibrating. By pouring the molten metal into the above consumable pattern 3 from a sprue cup 10, the molten metal is replaced with the above pattern 6 while the pattern 6 is burnt and consumed, and the product having entirely the same shape and dimension as the product pattern 6 is cast. In the above consumable pattern casting method, the guide hole 7 for molten metal communicated with the gate hole is arranged in the product pattern 6 and desirably, coating 11 containing additive contg. oxidizing source of iron oxide, etc., is supplied. By this method, the exhausting area of heat decomposed product with the molten metal is increased, and the vaporization and consumption of the heat decomposed product is accelerated and the carburizing into the low carbon casting product is prevented.