Abstract
On making ductile cast iron, molten iron is treated with inoculant such as magnesium. But the ability of inoculation thus obtained fades away after a while. The phenomenon of fading was studied by observing structural changes in gray iron and ductile iron melted with varying melting condition. The fading behaviour is effected by the condition whether melting is made under oxidizing condition or reducing condition. That is, fading occurs only under oxidizing condition but not under reducing. The degree of fading is changed with changing the kind of nodularized. For example fading more rapidly occurred in Mg. treated molten iron than in yttrium treated molten iron. When Mg. treated molten iron is remelted by using highly reducing flux such calcium carbide, no fading occurred, even though all the magnesium vaporized away from the molten iron.
