Abstract: Nowadays, the BOF-RH-CC technology process of producing ultra-low carbon steel is often applied. Through the slag blocking measures is applied during BOF tapping process, the slag in converter is still inevitable mixed with molten steel, the top slag has a strong oxidability. Many researchers found that high oxidizing slag deteriorate the cleanliness of molten steel and the oxygen content in the tundish. Tanaka pointed out that the mass fraction of FeO is more than 12% in slag will oxidate alloy elements such as Al, Ti in liquid steel, the formation of reoxidation inclusions that is easy to cause the clogging, affecting the surface quality of steel. While the top slag modified as an effective means of reducing slag oxidation has been widely recognized, the reasonable control of slag oxidation resistance is essential to the cleanliness of liquid steel. The high oxidation slag can cause reoxidation of molten steel in the subsequent process, traditionally oxidizing slag reduced to a lower level in the BOF tapping process, but the unkilled steel will cause the oxygen in the molten steel transfer to slag during the RH process, so in this paper slag deoxidant is added on the slag surface after BOF tapping to reduce slag oxidation, in the end of RH vacuum slag deoxidant evenly put into the slag surface further reducing slag oxidation, the TFe content in slag was reduced by adding slag deoxidant twice, the CaO/Al2O3 ratio is also considered in a reasonable range, reduce the oxidation of molten steel, improve the cleanliness of molten steel, which has important guidance in steelmaking.
Authors: Luo Yanzhao, Ji Chenxi, Wang Leichuan, Shan Wei, Cui Yang, and Tian Zhihong
Keywords: Slag Modification, Slag Oxidation, IF Steel, Inclusions