PURPOSE: To obtain castings of high density wherein no shrinkage holes exist at all in the stage of solidifying by adding metals satisfying specific conditions in amts. larger than the rate of shrinkage in the stage of solidifying to molten metal.
CONSTITUTION: The conditions required for the metallic elements to be added to molten metal of a metallic melt are that their m.p. is lower than that of the molten metal, that at least part thereof melt in the stage of melting and that the elements hardly form solid solns. with the element of the molten metal in the stage of solidifying. The reasons for requeiring said conditions lie in that if the m.p. is lower than that of the molten metal and part of said elements dissolve the crystallied metal of the element of the molten metal is enclosed by the additive metallic elements and shrinkage holes are packed in the stage of solidifying. If the additive elements form solid solns. with the element of the molten metal, the elements crystallize together with the element of the molten metal, thus resulting in a decrease in th additive metallic elements and failure in satisfactory packing. Al base alloys and/or Cu base alloys are used for the element of the molten metal, and 1 or ≥2 kinds selected from the group consisting of Bi, Ga, Ge, Sb, Si, etc. are used as the additive metallic elements.
SATOU TOMOHIKO
SHIMAMURA KEIZOU
