PRODUCTION OF NODULAR GRAPHITE CAST IRON AND INOCULANT USED THEREFOR

PURPOSE:To crystallize nodular graphite as cast effectively by adding an inoculant for alloys of iron contg. rare earth metals, Si, Mg and Ca in molten gray cast iron. CONSTITUTION:An alloy contg., by weight, 5-15% rare earth elements (RE), 40-80% Si, 0.5-2% Mg and 0.1-1.5% Ca and consisting of the balance Fe and unavoidable impurities is added to molten gray cast iron. Since this simply necessitates addition by changing, foundry treatment is easy, reaction time is extremely short, and the reduction in the temp. of the molten metal is reduced. Since no special elements such as Ti remain at the remelting of the return materials, there is no need for strict control of the return materials. Further, the less generation of oxides in the surface of the molten metal after the treatment and the high cleanliness of the molten metal lead to the considerable improvement in fluidity and the reduction in the amt. of addition of fuming elements such as Mg.