Spheroidisierbehandlungsverfahren molten metal of cast iron with nodular graphite

A graphite-Spheroidisiermittel comprising: 30 to 80 wt% Si;. mg; .. RE (rare earth element), the weight Ce with a purity of 80 to 100% by weight or La with a purity of 80 to 100% contains; Ca; and Al is used. The graphite-Spheroidisiermittel is added so that the conditions are satisfied, that an amount of RE, equivalent weight to 0.001 to 0.009.% Of the total weight of the molten metal, an amount of Ca, wt 0.001 to 0.02.% Of the total weight the molten metal is equivalent, and an amount of Al, 0.001 to 0.02 wt.% of the total weight of the molten metal equivalent, is added to the molten metal and the molten metal 0.03 to 0.07 wt.% mg after the graphite Spheroidisierbehandlung. It is possible to suppress the crystallization of chunky graphite in a thick portion of spheroidal graphite cast iron and the deterioration of mechanical properties at low cost.