Abstract
It is said that the characteristics of charcoal pig iron is a better suitablity for producing chilled iron rolls than the case of other pig irons, such as the coke pig iron, the electric pig iron, and the remelted pig iron.
In practice the following facts are the reason why the charcoal pig iron is used for manufacture of chilled iron rolls: its improvement of chilling effect, reduction of the mottle portion, least shrinkage difference between chill and gray iron, preferable graphitization in the gray iron core, slow cooling rate and increased fluidity of the molten iron.
Up to this time investigators have given no comment on these problems. The principal point of these characteristics presumably is a presence of numerous graphite particles in the core and a high heat content of the molten iron.
These characteristics have been considered to be caused by the nitrogen, the oxygen, the hydrogen, and the impurities. The author investigated experimentally these characteristics.
Three laboratories in Japan (Mechanical Laboratory of Japanese Government, Metal Research Institute of Tohoku University, Laboratory of Mitsubishi Kozai Co. Ltd.) carried out the gas analysis of the charcoal pig iron, the coke pig iron, the electric pig iron, and the remelted pig iron. It was found from this analysis little difference between those determination.
If the characteristics of charcoal pig iron have reference to the gas content, it is probably due to the state of the gas that has been indicated by Hiromu Tanimura1).
