| The effects of melting temperature and holding time on nucleation behavior of graphite were studied thor gray cast iron and for spheroidal graphite cast iron . As melting temperature and holding time were increased, the starting temperature for graphite-austenite eutectic solidification became lower, and the number of eutectic cell became less for the gray cast iron. For the spheroidal graphite cast iron, the degree of undercooling for the reaction became smaller and the amount of cell increased when holding time was 20 minutes, while, when the holding time was 40 minutes, an opposite trend was observed due to an effect of residual Mg within the molten stock. The effect of melting temperature on the amount of eutectic cell was more significant in the gray cast iron than in the spheroidal graphite cast iron. Dissolution of spheroidal graphite into the iron melt was observed to be more difficult than that of flake graphite. |
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