鑄鐵の生長に就て

Abstract

The growth of gray cast iron during repeated heatings and coolings has been studied by many investigators and three different theories were maintained as follows: (1) The permanent elongation is produced by the expansion of the occluded gases in the metal at high temperatures; that is, the gases in minute cavities expand at high temperatures and make the content of the cavities permanently larger, thus giving a great porosity and apparent growth to the metal.(2) The growth of gray cast iron is principally shown to be the result of the oxidations of carbon, silicon as well as iron. (3) The growth of gray cast iron during the first heating through 700°C to 800°C is partly attributable to the decomposition of cementite and the next continuous growth during heating and cooling through the A1 range is the effect of the differential expansion at different microportions of the same casting, numerous fissures or cavities being thus formed, in the region of graphite flakes; and in an oxidising attmosphere, the growth is accelerated by oxides formed and filling the fissures or cavities during Ar1 transformation, thus the effect of oxidation on the growth of cast iron is indirect. In this investigation, the effects of some elements as carbon, silicon, manganese, phosphorus, tin and chromium upon the growth of gray cast iron repeatedly heated were studied and also the growth on black heart malleable cast iron was observed. From these results of the experiments, the authour was discussed the above three theories on the growth of cast iron and given some complements to his previous theory explained in the above term (3)