Change in Inclusion Composition during CaO Flux Powder Blowing under Reduced Pressure

Abstract

To examine the reaction mechanism of the variation of calcium content in inclusions and the molten steel and the effect of flux composition on the reaction, the variations of molten steel content and inclusion content during CaO, 60%CaO–40%CaF₂ or 50%CaO–50%CaSi powder blowing onto the molten steel under reduced pressure were investigated with 15 kg scale experiments. From the experimental results, it was found that the inclusion composition was changed from Al₂O₃ to Al₂O₃–CaO by CaO flux that did not contain CaSi alloy, and that the reaction path of the inclusion composition was changed remarkably by CaSi alloy in CaO flux. From the experimental results and the chemical thermodynamic calculation, the effects of the flux and CaSi alloy on the change in composition of inclusion and melts were examined.