Abstract
The growth of spheroidal graphite cast iron made by calcium addition was examined during repeated heatings from 600° to 900°C and compared with the growth of some other cast irons i. e. the spheroidal cast iron made by magnesium or comparatively high nickel and the flaky graphite cast iron of normal type. If the spheroidal iron made by calcium silicide gave a nearly perfect structure of spheroidal graphite, the growth hardly occurred, while the mixed structure with flaky and quasi flaky graphite gave an appreciable growth. Because of the silicon content over 3 per cents in the spheroidal graphite iron, a ferrite-type structure was apt to be detected. For these cast irons, the transformation point existed in a few repeatings of heating, and disappeared after a several periods of repeated heating.
