关键词: IF钢, 300t RH循环时间, 脱氧, Al₂O₃夹杂

Abstract: The oxygen content in IF steel (/% ：≤0.005C, ≤0.04Si, 0.05~0.20Mn, ≤0.015P, ≤0.015S, 0.03~0.06Als) before adding aluminium in RH refining process is 340 x 10^-6~467 x 10^-6, and the types, size and number of inclusions in steel after adding aluminium for 2~10 min have been studied by ASPEX scanning electron microscope. Results show that the main type of inclusions in IF steel alter deoxidation by adding aluminium in RH refining process is alumina, with increasing circulation time of RH refining the number of inclusions in liquid decreases ； with after adding aluminium for 6 min it is available to alloying operation and further prolonging circulation time the removing rate of inclusions in liquid slows down； as the initial oxygen content in IF liquid before adding aluminium is rather higher, it may be appropriate to extend circulation time to 8 min then to alloying.

Key words: IF Steel, 300 t RH Circulation Time, Deoxidation, Al₂O₃ Inclusions