<論文>フェライト質片状黒鉛鋳鉄の熱膨張式について

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Gray cast iron, subjected to repeated heating at higher temperature in vacuum, shows a tendency to increase in volume. According to the suggestion recently made by K. Nagaoka, I. Hagiwara and M. Soma, an essential condition of this growth is the generation of the porosities which are generated in the graphite crystals in cast iron, accumulating some of the vacancy which is generated when carbon atoms on their surface are dissolved into the matrix iron in the process of heating. But the presence of porosities is yet to be proved hereaffer, and no one has ever ascertained the temperature of the generation of the porosities and the quantity of the porosities. Therefore, to ascertain these points, the total volume of the vacant space in terms of quantity of the carbon dissolved into iron was calculated, and finally the amount of thermal expansion of cast iron according to the degree of the retaining of vacant spaace was calculated. And then it was compared with experimental thermal expansion. Thus it has been recognized that flaky graphite cast iron, a most popular cast iron, expands almost as calculated. And generally a few parts of the vacant space diffuse out of cast iron, and the rest remains in it.
1980-03-15