高純度鋳鉄の基地組織に及ぼす微量元素の影響 Effects of Trace Element on Ferritization of High Purity Cast Iron
The ferritizing process of high purity cast iron was investigated. Specimens used for the experiments were pure Fe-C-Si, Fe-C-Si-P, Fe-C-Si-S, Fe-C-Si-P-S alloys and commercial grade cast iron. The specimens used for the investigation were packed in a container with electrode graphite and fully annealed during two stages in air or argon atmospheres. The first stage was fixed at 1173K for 3 hours while the second stage, the cooling stage from 1173K to 973K was performed at various times such as 5, 10, 20, 40, 80 hours. The results obtained were as follows : 1) The ferritization of pure alloy is difficult to compare with that of commercial grade cast iron. 2) The pure alloys are ferritized easily in argon atmosphere annealing. 3) The titanium in the commercial grade cast iron combines with the nitrogen in iron to form TiN. As it decreases the effect of nitrogen on pearlitization, the ferritization is accelerated. 4) Due to the low Ti content of pure alloys, nitriding occurs when heat treatment is performed, thus preventing ferritization. 5) The ferritizing speed of the specimens decreases in the following order C. G. , 7P, 7P-4S, B, 4S.
- 鋳造工学 = Journal of Japan Foundry Engineering Society
鋳造工学 = Journal of Japan Foundry Engineering Society 70(8), 569-574, 1998-08