Effects of Slag Composition and Impurities of Alloys on the Inclusion Transformation during Industrial Ladle Furnace Refining
Chunyang Liu,
Yi Jia,
Lixia Hao,
Shaowei Han,
Fuxiang Huang,
Huixiang Yu,
Xu Gao,
Shigeru Ueda,
Shin-ya Kitamura
Affiliations
Chunyang Liu
Steelmaking Plant of Beijing Shougang Co., Ltd., No. 25 Zhao’an Street, Western Industrial Zone, Qian’an, Tangshan 064400, China
Yi Jia
Steelmaking Plant of Beijing Shougang Co., Ltd., No. 25 Zhao’an Street, Western Industrial Zone, Qian’an, Tangshan 064400, China
Lixia Hao
Steelmaking Plant of Beijing Shougang Co., Ltd., No. 25 Zhao’an Street, Western Industrial Zone, Qian’an, Tangshan 064400, China
Shaowei Han
Steelmaking Plant of Beijing Shougang Co., Ltd., No. 25 Zhao’an Street, Western Industrial Zone, Qian’an, Tangshan 064400, China
Fuxiang Huang
Steelmaking Plant of Beijing Shougang Co., Ltd., No. 25 Zhao’an Street, Western Industrial Zone, Qian’an, Tangshan 064400, China
Huixiang Yu
School of Metallurgical and Ecological Engineering, University of Science & Technology Beijing, 30 Xueyuan Road, Haidian Distinct, Beijing 100083, China
Xu Gao
School of Metallurgy and Environment, Central South University, Changsha 410083, China
Shigeru Ueda
Institute of Multidisciplinary Research on Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba ku, Sendai 980-8577, Japan
Shin-ya Kitamura
Emeritus Professor of Tohoku University, Sendai 980-8577, Japan
The inclusion of the MgO·Al2O3 (MA) spinel and CaO–Al2O3 are occasionally observed during the refining of Al–killed steel, even without the intentional additions of Ca and Mg. Many studies have focused on the source of Mg and Ca; however, especially for the formation of CaO–Al2O3–type inclusions, some recent results showed that Ca was difficult to dissolve from refining slag, even when the Al content in molten steel was high. To confirm these differences, industrial experiments were designed in this study, and the effects of the FeO and MnO contents, as well as the impurities of the alloying materials, were discussed. The results showed that, when the FeO and MnO contents in slag were high (about 10 mass%) at the start of LF (ladle furnace), all inclusions remained as Al2O3, despite alloying. Using the slag with low FeO + MnO content (2O3 inclusions changed to the MA spinel, but CaO–Al2O3 inclusions were not observed, indicating that CaO–Al2O3 inclusions were difficult to form by the steel/slag reactions under the current conditions. Only for the molten steel that contained a low level of dissolved oxygen and a large amount of Fe–Si, which contained Ca as the impurity was added, CaO–Al2O3 inclusions were generated.
