Abstract
In this report, the relation between graphitization and decarburization of white cast iron in the process of annealing of white heart malleable cast iron was studied. When free cementite in cast iron was diminished by decarburization, it changed to austenite or ferrite. When granule rtemper carbon was decarburized,however,sufficient carbon would diffuse to matrix at first. After some time this diffusion of carbon weakened because some gap broke out between temper carbon and matrix. Such a granular carbon declined by decarburization can not become a source of carbon on decarburization or a collecting nucleus of carbon on graphitization.
Many experimental results which occurred on annealing of white heart malleable cast iron can be explained by the fact mentioned above.
The effect of some elements contained in it such as C, Si, Mn,P, S, Ni and Cr on carbon concentration of decarburized zone was studied in comparison with the effect on graphitization, but could not find a definite connection between those phenomena.
