EFFECT OF AR BUBBLING ON REMOVAL RATE OF ALUMINA INCLUSION IN AL DEOXIDIZED STEEL

Effect of Ar bubbling on the deoxidation rate of molten steel with Al has been investigated in 20 kg scale induction furnace. The results ar e summarized as.(1) The deoxidation was completed within 5 to 15 min d epending on experimental conditions. The final total oxygen content wa s 30 to 45 ppm. (2) The deoxidation model has been proposed in which d eoxidation rate should be determined by the balance of removal and ree ntrainment rates of alumina inclusion; (3) The removal rate constant w as obtained at each condition. The apparent activation energy was obta ined as 284, 355, 368 kJ/mol, respectively with Ar now rate of 0, 5, 1 01(STP)/min. (4) The removal rate constant was expressed as a function of total stirring energy density for induction stirring (epsilon(ind) ) and Ar gas stirring (epsilon(B/B)), namely, k-k(1)(epsilon(ind) + ep silon(B/B))(n). The value of n was obtained as 0.50 to 0.65. (5) The c ontribution of entrapment of inclusion in bubbles was estimated quanti tatively. The transfer coefficient of inclusion migration to bubble wa s also estimated.