Regular Article

Research on the oxygen content in 304L stainless steel during VOD-LF-CC process based on IMCT

¹ State Key Laboratory of Advanced Metallurgy, University of Science and Technology, Beijing 10083, PR China
² Hongxing Iron & Steel Co. Ltd., Jiuquan Iron and Steel Group Corporation, Jiayuguan 735100, Gansu, PR China

^* e-mail: chengguoguang@metall.ustb.edu.cn

Received: 23 January 2019
Accepted: 27 September 2019

Abstract

The total oxygen in 304L stainless steel produced by the VOD-LF-CC process is investigated in this research. The equilibrium oxygen content in the molten steel during the smelting process is calculated based on the ion-molecule coexistence theory. The results show that it is feasible to use the developed thermodynamic model for calculating the equilibrium oxygen content in CaO–SiO₂–Al₂O₃–MgO–FeO–Cr₂O₃ slags equilibrated with 304L molten steel. The variation law for total oxygen is in good agreement with the equilibrium oxygen content. The oxygen content of the oxide-inclusion decreases with the number density of inclusions, which decrease at different stages in the process. The content of FeO and Cr₂O₃ in the slag has no obvious effect on the equilibrium oxygen content when the basicity of the slag remains constant. Combining the proposed method with industrial practice, the optimum VOD process parameters for obtaining a low equilibrium oxygen content are as follows: 1600–1650 °C of the temperature after the VOD stage, 0.4–0.5% of the Si content after reduction, and 2.2–2.5 of the slag basicity.