Control Technology of Aluminum Content and Inclusion Composition in High-silicon and Aluminum-controlled Steel

In present paper，the control technology of aluminum content and inclusion composition was analyzed for high-silicon and aluminum-controlled steel by technological test. The results showed that content of Al in steel can be controlled within 0.0040% by using low basicity slag with alkalinity below 1.5，while the Al content is higher than 0.006% by using high basicity slag with basicity 2.5 - 3.5. The decrease of Al₂O₃ content in slag is beneficial to decrease the amount of Al increase in molten steel.The oxide inclusion component in low basicity slag steel is SiO₂-MnO-Al₂O₃-MgO-CaO series ， which achieves the control of inclusion plasticization. The oxide inclusion component in high basicity slag steel is Al₂O₃-SiO₂-MgO-CaO series with high Al₂O₃content， and the plastic deformation ability of the inclusion material is insufficient. High clean steel with oxygen content less than 0.001 2% and fine inclusions can be obtained after RH control processing， although deoxygenation effect of the steel with low basicity slag is poor in the refining process.