Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
The Relationships among Graphite Precipitation, Gas Exhaustion, Specific Heat and Dilatation of Various Species of Pig Iron during Heating
Kokichi Otani
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1958 Volume 44 Issue 2 Pages 116-121


In regard to the graphite precipitation of various species of pig iron, the author measured the specific heat and the thermal dilatation with the specimens which had been vacuum-heated for gas exhaustion, and the results of these tests were indicated as follows:
1) Gas exhaustion: The temperature of gas exhaustion from charcoal grey iron made by the Teikoku Seitetsu Co. was 200 to 300°C, and that from the Teikoku charcoal mottled iron was 1, 000 to 1, 200°C. The gas of Kamaishi grey iron was exhausted at a temperature of about 300 to 400°C, and the temperature of gas exhaustion from the electric white iron made by the Nisso Seiko Co. was not examinated by this test.
2) Anomalous specific heat of vacuum-remelted specimens: The coarse microstructure of specimens of the virginal charcoal iron turned to the fine microstructure and the anomalous specific heat of it was not presumed a principal consequence by the vacuum-remelting. In the coke pig iron, the flake graphite was changed to the eutectic graphite and the anomalous specific heat became greater. In the Nisso electric iron, however, the microstructure & the anomalous specific heat were not changed at all.
3) Thermal dilatation: In regard to the Teikoku charcoal iron, the thermal dilatation at a temperature higher than 500°C in vacuum was much more than that in argon gas under 1atm. Therefore, it was presumed that the graphite precipitation was more prominent in vacuum than in argon.
In regard to the Nisso electric iron, the thermal dilatation of the iron at a temperature lower than 600°C was less than that of the other species of pig iron in both of vacuum & the argon under the pressure of 1atm. At a temperature of about 800°C, the thermal dilatation in vacuum was more remarkable than that in the argon under the pressure of 1atm.

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© The Iron and Steel Institute of Japan
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