Abstract
Electrolytic iron and crystalline electrode graphite or non-graphitizing carbon materials (furnace and channel carbon blacks, furan resin carbon and saccharose carbon) with different facility of graphitization compared with electrode graphite, were subjected to carburizing treatment at 1573 K or 1873 K in a high frequency induction furnace in vacuum. The influences of various carbon materials on the properties of cast iron melt were investigated by examining the micro-structure and the average carbon contents of samples obtained. In the case of electrode graphite, although carburizing into solid iron was very difficult, the dispersion of graphite into liquid iron occured easily and thus the electrode graphite promoted the nucleation and growth of stable graphite-γ eutectic. In the case of non-graphitizing carbon materials, although carburizing into solid and liquid iron was easier with a decrease in the degree of graphitization, and the dispersion of carbon matelials into liquid iron were promoted with an increase in the degree of graphitization. The nucleation and growth of graphite-γ eutectic were more difficult with a decrease in the degree of graphitization, while those of the metastable cementite-γ eutectic were promoted. Though carbon content in the melts at 1873 K hardly changed for all carbon meterials, their behavior to the iron differed remarkably by the sort of carbon precursor and graphitization temperature of carbon materials. These facts indicate clearly that the properties of carburized melt (the state of the presence of carbon-microgroups) depend on the structural characteristics of carbon materials.
