| For the purpose of investigating the behaviour of residue Mg in the spheroidal graphite cast iron, the effect of additional amount of Fe-Si-Mg and cooling velocity on the graphite shape were studied by photomicrograph and EPMA. The principal results are as follows. (1) As the additional amount of Fe-Si-Mg and cooling velocity decreased, the degree of graphite spheroidization increased partly. (2) In the case of different cooling velocity, in spite of the same degree of graphite spheroidization the shape of graphite distribution was different. (3) There were little residue Mg and Si in the graphite, but they are much in a boundary of graphite and matrix. In case of spheroidal graphite, the degree was more extreme than that of flake graphite. (4) Silicon content was greater where the residual Mg remained more. |
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