PURPOSE:To prevent the stripe pattern and sand floating on the surface of a casting mold by adjusting respectively the average grain size and standard deviation of the grain size distribution of sand within specific ranges and using a binder composed of a novolak or resol type phenolic resin or a resin mixture composed of both resins which have respectively average mol.wt. in specific ranges. CONSTITUTION:The average grain size of the grain size distribution of the molding sand is adjusted to =70mum and =350mum in a sand mold method of a centrifugal casting method. The standard deviation of the grain size distribution is adjusted to =50% average grain size. The binder to be used is the novolak type phonolic resin or resol type phenolic resin or the resin mixture composed of both resins. The stripe pattern and sand floating on the surface of the casting mold are eliminated when the average mol.wt. of the respective resins are adjusted 250-600.
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