Abstract
Studies were made on the crystallization of primary graphite in hyper-eutectic melts and on carbide matastabilizing tendency occuring at the time of solidification. It was found that the melts with high hyper-eutectic composition can crystallize the primary graphite even by rapid cooling such as quenching in water. As the contents of carbon and silicon increased, carbide metasrabilizing tendency decreased, and as the composition of alloy approached that with the liquidus of graphite of 1,450°C, cementite was not formed at all even in the castings which solidified in nearly five seconds. Presumably, such lowering of carbide metastabilizing tendency is caused by the existing primary graphite which absorbs the carbon formed by eutectic reaction L→γ+C, preventing the metastable reaction.
