To provide a graphite spheroidizing agent by which the additive quantity can be made to a value equal to or lower than that in the case of treatment using conventional graphite spheroidizing alloy by a sandwich method and further treatment under gentle reaction can be done and also the amount of generation of magnesium-silicate-type and calcium-type dross and slag can be minimized.
The inside of a sheath material 3 composed essentially of iron is filled with a granular filler 2 composed of a mixture of metal magnesium Mg and iron powder. The weight ratio of the Mg component in the filler 2 is made to 3-12% based on the whole of the compound graphite spheroidizing agent, and the balance of the filler 2 is composed essentially of iron. Further, the weight proportion of the sheath material 3 is made to ≥60% based on the whole of the compound graphite spheroidizing agent, and also pressing is carried out so that the density of the filler becomes ≥4.0.
MIYAKE MAKOTO
ITO YUJI
TAKEUCHI KOJI
MATSUDA KOKICHI
