ダクチル鑄鐵の生長について

概要

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The growth of ductile cast iron by repeated cyclic heating were measured in air and vacuum in comparison with other type cast irons and in order to observe the process of growth, some experiments were performed by a dilatometer and micro-structure and strength of these cast irons after cyclic growth were also examined. The results obtained were as follows : (1) Growth of ductile cast iron both in air and vacuum were less than that of normal cast iron melted with same conditions except magnesium treatment in ladle, and the growth increased by remelting. (2) Growth increased with elevated heating temperatures (750∿950℃), but the effects were poor. (3) Oxidation effects and decrease of strength by cyclic heating were not apparent. (4) With the same rate of cooling and heating on the curves of length-change of ductile cast iron the Ar_1 expansion and the Ac_1 contraction apparently were not found, but with other type cast irons these changes appeared. Consequently in the microstructure of ductile cast iron more ferrite were observed. (5) The growth of ductile cast iron were caused namely by the locational irreversibility of graphite reformation during the heating and cooling, and growth of cast iron varied with the mechanism of ferrite formation through critical range and the effects of oxidation for each cast iron.
社団法人日本鉄鋼協会の論文
1953-11-25