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Reoxidation of Al‐ K illed Molten Steel by Fe 2 O 3 and Cr 2 O 3 in the Magnesia‐ C hromite Refractory
Author(s) -
Jiang Fang,
Cheng Guoguang,
Xie You,
Qian Guoyu,
Rui Qixuan,
Song Yunxia
Publication year - 2013
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201200311
Subject(s) - chromite , metallurgy , materials science , magnesium , chromium , steelmaking , molten salt
In the present work, the reoxidation of Al‐killed molten steel from the magnesia‐chromite refractory was investigated. Firstly, the composition and the phases of magnesia‐chromite bricks from three different steelmaking shops were analyzed. Secondly, the magnesia‐chromite bricks were immersed in Al‐killed molten steel for a determined time to observe the reaction mechanism. Finally, the reoxidation of Al‐killed molten steel by the magnesia‐chromite bricks was evaluated based on a comparison with the pure magnesia crucibles. The XRF showed the Fe 2 O 3 content of the magnesia‐chromite bricks is about 6 mass%, and the Cr 2 O 3 content is in a range of 13–19 mass%. The XRD pattern showed the phases in the bricks are mainly MgO and (Mg,Fe)(Cr,Al,Fe) 2 O 4 . The fracture surface of magnesia‐chromite bricks after immersion in Al‐killed molten steel indicated that there exists a reacted layer, and the reacted layer formed after immersion in the low Cr steel is more obvious than that formed after immersion in the high Cr steel. The SEM–EDS of magnesia‐chromite bricks showed that (Mg,Fe)(Cr,Al,Fe) 2 O 4 in the reacted layer decreased after immersion in Al‐killed molten steel, especially in the low Cr molten steel. Compared with steel melted in pure magnesia crucibles, the total oxygen of steel melt in magnesia‐chromite crucibles showed a lower decreasing rate, and the rate of Cr increase and Al loss were much larger, especially in the low Cr molten steel.