PURPOSE: To obtain a molten metal for highly graphitizable cast iron made low in chill crystallization without adding or inoculating any alloy to the molten metal, by using shaft furnace molten iron having unmelted graphite present therein as a molten stock materal.

CONSTITUTION: Molten iron tapped from a shaft furnace is mixed in an amount of 40W80% as a stock material for melting. By this method, unmelted graphite carried by the molten iron is present in molten cast iron as it is and, because it acts as a solidification nucleus, extent of super cooling becomes small and chill crystallization is prevented while graphitization is promoted. By this method, because of the sensible heat possessed by the molten iron itself, power consumption and a melting time can be reduced.