PURPOSE:To reduce the amount of production of free carbon and make possible application to cast steel of less carbon contents by incorporating resins of olefin base as the main components of the pattern. CONSTITUTION:A foamed resin pattern 1 is formed by the material comprising being composed primarily of olefin-base resins such as polyethylene and adding foaming agents, etc. A sprue 4 is also formed by the same material. The foamed pattern 1 is put in a flask 2 and is buried in molding sand 3, whereby molding is done. Molten metal is poured through the sprue 4 and the pattern 1 is extincted by the heat of the molten metal to fill the molten metal in the cavity created thereby, whereby the molding is made. Since this pattern using the olefin-base resins is high in stability to solvent, the pattern does not deform and the casting of high dimensional accuracy is obtained.
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