Influence of molten steel composition on modification effect of inclusions during calcium treatment
LI Chao1, LI Jian-xin1, JIANG Jing-yu2, YIN Zheng-yuan3, ZHANG Fei1, LIU Zhan-li1
1. Technology Research Institute, HBIS Group, Shijiazhuang 050023,Hebei, China; 2. Wusteel, HBIS Group, Wugang 462500, Henan, China; 3. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
Abstract：Calcium treatment is a common method to solve the problem of nozzle clogging in aluminum killed steel production. The influence of molten steel composition on modification effect of inclusions during calcium treatment was studied by industrial experiments and theoretical calculation. The thermodynamic calculation of FactSage showed that the modification of inclusions during calcium treatment was closely related to the relative content of oxygen and sulfur in the molten steel at a certain temperature. When the oxygen content was fixed, within a certain range, the higher the sulfur content, the smaller the maximum liquid phase ratio of inclusions at equilibrium, and the narrower the process window of feeding calcium. While, when the sulfur content was fixed, the higher the oxygen content within a certain range, the larger the maximum liquid phase ratio of inclusions at equilibrium. In the industrial test, the typical inclusions in steel with low oxygen content and high sulfur content were magnesium aluminum spinel and CaS composite inclusions with high melting point. However, the typical inclusions in steel with relatively high oxygen content and low sulfur content were mainly calc-aluminate with low melting point. The results of industrial experimental analysis were consistent with the trend of theoretical calculation.
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2020, Vol. 30 
