To make it possible to control the outflow rate of molten steel stable in multiplex casting as well by press molding a compd. contg. graphite and refractory aggregate composed mainly of alumina, then firing the molding.
The compd. is obtd. by compounding 3 to 25 wt.% graphite, such as flaky graphite, 75 to 97 wt.% alumina, and the refractory aggregate consisting of 100 wt.% refractory raw material, such as zirconia, magnesia and spinel and 0.5 to 4 wt.% (outer) antioxidant selected from Al, Si, Mg, B4-C, Al-Si and Al-Mg, etc. A phenolic resin and/or a binder of ≤0.05 grain size, such as pitch, is added to the compd. and after the mixture is kneaded, the mixture is press molded by a rubber press, friction press, oil press, etc., and the molding is fired at 800 to 1400°C in a reducing atmosphere, by which a stopper head for a tundish not contg. an SiO2 component or contg. SiO2 at <1 wt.% and having the chemical characteristics corresponding to the wear by the reaction with molten steel is obtd.
SOMA MASAHIRO
NAKAMURA MAKOTO
SAI KATSUAKI
NIPPON STEEL CORP