The Growth of Grey Cast Iron : Third Report

Abstract

The present investigation was carried out to make clear the relation between the growth of grey cast iron due to the abnormal expansion at Ar transformation and that due to oxidation. The various kinds of dilatometer were used for this purpose. According to the author's results, when grey cast iron is repeatedly heated at a high temperature in air, growth takes place principally due to oxidation and growth of this kind is much larger than that due to the abnormal expansion at Ar transformation. It is acceptable that grey cast iron becomes susceptible to oxidation by passing through its Ar critical range, hence its growth is accelerated by oxidation. But the author cannot agree with the investigations who believe that the abnormal expansion at Ar transformation is a direct cause of growth in every case, the effect of oxidation being indirect.