China Nonferrous Metallurgy

The size of alumina inclusions significantly affects the properties of steel, and the properties of steel can be enhanced by refining or eliminating the inclusions. The modification process of inclusions was simulated through adding different proportions of rare earth oxides La₂O₃/CeO₂ and Al₂O₃ at 1200℃ and 1600℃. The modification processes of La, Ce and Al oxides were characterized via X-ray diffraction and Raman spectroscopy. The half-height and width data of XRD peaks were calculated by using Jade 6 and Halder-Wagner (H-W) model to calculate the average grain size after sintering. The results indicate that under the conditions of Al₂O₃:(Al₂O₃+La₂O₃) being 0.4 and a sintering temperature of 1600℃, La shows the best modification effect on alumina inclusions. The characteristic peaks of the product AlLaO₃ are significantly enhanced, with no characteristic peaks of La₂O₃ observed, and the characteristic peaks of Al₂O₃ are noticeably weakened. The minimum grain size of the sintered product is 0.1347μm. Under the conditions of Al2O3:(Al₂O₃+CeO₂) being 0.4 and a sintering temperature of 1600℃, Ce demonstrates the best modification effect on alumina inclusions. The main sintering products are CeAlO₃, CeO₂ and Al₂O₃ and the characteristic peaks of the product CeAlO₃ are also significantly enhanced. The minimum grain size 0.5261μm. Both La and Ce can effectively improve alumina inclusions, undergoing processes of encapsulation, gradual substitution, and phase transition, ultimately transforming irregular, angular Al₂O₃ into nearly spherical, oval, or block-shaped rare earth aluminates. La exhibits a better modification effect on alumina inclusions compared to Ce.