Hitachi Metals, Ltd.

Hideharu Nakano

Masahide Kawabata

Masahiro Takahashi

Katsuhiko Kojo

Senri Okada

Yoshio Igarashi

Toshiki Yoshida

Kenya Matsuyama

An additive for use in producing spheroidal graphite cast iron of the present invention contains a fine particle of magnesium oxide having a purity of 90 weight % or more and at least one selected from the group consisting of a graphite-spheroidizing material, an inoculant and a graphite-spheroidizing inoculant. The fine particle of highly pure magnesium oxide increases the number of nuclei in a melt, and as a result thereof, increases the graphite spheroid count of a spheroidal graphite cast iron being produced. Another additive for use in producing spheroidal graphite cast iron of the present invention contains at least one selected from the group consisting of a graphite-spheroidizing material, an inoculant and a graphite-spheroidizing inoculant, and an oxide of a metal which has, at a temperature of a melt at a time when subjected to a graphite-spheroidizing treatment, an affinity for oxygen smaller than that of a graphite-spheroidizing element being used in the graphite-spheroidizing treatment. By adding to the melt the metal oxide which oxidizes the graphite-spheroidizing element in the melt to an oxide thereof, a great number of fine oxide particles of the graphite-spheroidizing element is dispersed in the melt to provide a spheroidal graphite cast iron having a great number of fine graphite spheroids and a small chill area ratio.

Additive for use in producing spheroidal graphite cast iron

Growing community of inventors

Tochigi-ken, Japan

Hideharu Nakano