蠕虫状石墨铸铁的凝固过程

通过对各种处理剂处理的蠕虫状石墨铸铁凝固过程的研究，明确了共晶凝固时石墨的析出过程。共晶凝固过程可分为两个阶段：第一阶段形成球状石墨，随之被析出的奥氏体壳包围；第二阶段形成蠕虫状石墨，由于包围球状石墨的奥氏体部分熔解，使石墨与熔液接触生长。说明共晶凝固第一阶段形成的球状石墨成为蠕虫状石墨生长的起点。

SOLIDIFICATION PROCESS OF COMPACTED VERMICULAR GRAPHITE CAST IRON

Solidification process of CV graphite iron with the addition of various CV-graphitizing materials and the crystallization behavior of the graphite during. The eutectic reaction was clarified. The two ,arrest stage on the cooling curve during the eutectic freezing were observed in the cast iron with CV graphite. In the first stage of the arrest, the spheroidal graphite nucleated prior to the eutectic freezing and grew with austenite shell. The CV graphite was formed in the second stage and grew in contact with the liquid due to partial dissolution of the austenite shell surrounding the graphite spheroid. Accordingly, it was suggested that the graphite nodules formed in the first stage of e4tectic freezing were served as the starting point of CV graphite growth.