ブローホール欠陥発生に及ぼす耐火物・溶鋼間反応の影響

抄録

The effect of the inner porous refractories-molten steel reaction on the incidence of blisters and the mechanism whereby the incidence of blisters is prevented by using an immersion nozzle with a silicaless inner porous refractories that does not react with the molten steel were studied. The following results were obtained :
(1)Blisters are caused by 0.5 mm and larger argon gas bubbles, and particularly 1.0 mm and larger argon gas bubbles have a direct bearing on the incidence of blisters in the sheet product.
(2)The mechanism whereby the incidence of blisters depends on the number of sequence cast heats can be explained by the increase in argon gas bubble diameter with the increase in the inner porous refractories-molten steel reaction in the later heats in the sequence cast.
(3)Fine argon gas bubbles can be stably injected into the molten steel by using an immersion nozzle with a silicaless inner porous refractories that does not react with the molten steel. This stable injection of fine argon gas bubbles helps prevent the occurrence of blisters in the sheet product.