Investigation On Interaction Between MgO-Al₂O₃ Refractory And Molten Steel In Refining Process

With the higher demands of customer, inclusion controlling in the steel is the important problem among the steel manufactory recent. Ladle refining is one of the key methods to improve the purity of the steel. LF process is one of widely application ladle refining process, but this process gives a very rigid demand on the refractory materials for lining. The erosion and dissolving process of lining may reduce the purity of the molten steel. This kind of re-pollution of steel should be considered to reduce. Thus, the interactions and mechanism of reactions between the molten steel and refractory in LF furnace were instigated in this paper.Since the plenty of Magnesium and Aluminum resource in China, 82B steel was molting in the crucibles with different compositions of MgO or Al2O3 based castable as the raw material. The influence of different refractory to the inclusions in the steel was studied. The results showed that Si riched SiO₂-Al2O3 inclusion was found in the steel samples from Alumina riched crucible, the size of this inclusion was large, and the hardness of this inclusion was high. Silicate of Magnesium and Calcium is the main phase in the inclusion SiO₂-MgO-CaO system was found in the steel samples from magnesia riched crucible, the size of this inclusion was small, and the hardness of this inclusion was low, this inclusion has very good plasticity. Magnesia riched refractory may be good to the producing of clean steel.Refractory materials, which are applied in ladle now, dissolving into molten steel equilibriums, are considered. Spinel was found relative low solubility in the molten steel. MgAlON was also considered. MgAl₂O₄-MgAlON composite could reduce the corrosion of lining. It would be good to the refining and prolonging the life of the lining.MgAl₂O₄ and MgAl₂O₄-MgAlON composite were synthesized in lab, and the corrosions of these two refractory materials in molten steel were investigated also. The results showed that the increasing amount of MgAlON could reduce the solubility in the molten steel and increase the ability of anti-penetration. When the mass percent of MgAlON was 30%, the anti-corrosion capacity of MgAl₂O₄-MgAlON reached the maximum; it would be twice of the one for MgAl₂O₄.