Effect of Chemical Components of Mould Flux on Dissolution Rate of Al2O3 into Molten Flux for High Manganese High Aluminum Steel

A mass of Al2O3 tends to form during the continuous casting process of high manganese high aluminum steel, and the properties of mould flux and the quality of slab are seriously affected. The dissolution rate of Al2O3 into the CaO-SiO2-MgO-Al2O3-F--Na2O-Li2O-BaO-B2O3 slag system has been investigated at 1573 K by employing rotating cylinder method. This paper focuses on the effect of Na2O, Li2O, B2O3, F-, Al2O3 contents and (CaO+ BaO)/(Al2O3+SiO2) ratio on the dissolution rate. Experimental results show that the dissolution rate increases with increasing Na2O, Li2O, B2O3 contents and decreasing Al2O3 content, among which Li2O has the greatest effect on increasing dissolution rate; the dissolution rate increases with increasing F-content in slag A-1, but decreases with that in slag A-2; the dissolution rate increases with (CaO+ BaO)/(Al2O3+SiO2) ratio within the range from 0.91 to 1.31. The dissolution rate of Al2O3 into molten flux is mainly affected by the viscosity of the molten flux and the thermodynamic driving force.