1.School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing,Beijing 100083,China;2. No.2 Steel Making Plant, Shougang Co Ltd, Beijing 100041, China
Abstract:The sources of inclusions in steel during the CASOB refining and slab continuous casting process were investigated by means of tracer method. Results show that the microinclusions in steel both in the refining process and after calcium treatment include La which is the tracer in ladle slag. Microinclusions in steel from tundish include both La and Ce which is the tracer in tundish flux. Micro-inclusions in slab include part of La, Ce, K and Na. The reason is that the deoxidization products in molten steel react with the ladle slag, tundish flux and mould flux. The macroinclusions in slab are mainly from the mould flux, and secondly from the ladle slag, and less from tundish flux. Macroinclusions include trace elements of La, Ce, K and Na simultaneously. Macroinclusions are composite inclusion of deoxidization products with the ladle slag, tundish flux and mould flux entangled into the molten steel.