COLLAPSIBLE MOLDING MATERIAL

摘要

PURPOSE:To obtain a molding material of good collapsing property by mixing the ethyl silicate prepd. by adding an alkali to mixed powder consisting of quicklime powder and added with silica powder and adding water to make these into a slurry. CONSTITUTION:Mixed powder consisting of 65-95wt% quicklime powder of <=80 meshes and the balance silica powder is prepd. Ethyl silicate added with about 1% alkali is added to the mixed powder and these are mixed; further, water is added thereto to prepare a slurry. When this slurry is cast into molds, it is geled and caked by the hydrolysis of the ethyl silicate to form a mold. This is calcined at 900-1,100 deg.C. This mold collapses easily and the strength of core is extremely weak.