Mold Simulator Study of the Initial Solidification of Molten Steel in Continuous Casting Mold. Part I: Experiment Proces

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ce defects in the final rolled product have been found to be associated with the surface defects of the strands,[1–3] and most of these surface defects, such as oscillation mark, depression originate from the initial shell solidification. Many efforts have been conducted to study the effects of casting parameters, mold oscillation together with mold flux properties on the formation of slab surface defects. The methods to conduct above issue include on-site operational experiments, pilot scale experiments, cold-state simulate experiments, mathematic model, and laboratory scale experiments. Conducting experiments on an industrial continuous casting mold and pilot plant[4] are considered to be an ideal way for the study of the initial solidification behavior of molten steel, but it is not always feasible due to the practical constraints of various process variables which makes the control of the experiments extremely difficult. The cold-state simulate experiments through the using of low melting point material, such as organic substances[5] or Sn-Pb[6–8] alloys, are convenient and efficient to study the effect of different operation parameters on the initial shell solidification behaviors. However, this method cannot reflect the actual molten HAIHUI ZHANG, Ph.D. Student, WANLIN WANG, Shenghua Professor, FANJUN MA and LEJUN ZHOU, Lecturers, are with the School of Metallurgy and Environment, Central South University, Changsha, 410083 Hunan, P.R. China. Contact e-mail: wanlin. [email protected] Manuscript submitted January 7, 2015. Article published online July 9, 2015. METALLURGICAL AND MATERIALS TRANSACTIONS B

steel solidification behavior, in which the mold flux infiltration in between the mold and shell was missing. Mathematic models have been developed for such investigations, and analytical expressions[9,10] have been established to predict the initial shell solidification, the oscillation marks formation, and the slag infiltration. Besides, numeric simulation[11–14] regarding to the mold oscillation has been carried out to simulate the shell solidification and the possible shell surface defects formation during the initial shell solidification. Recently, Thomas, et al.[15] have built a numeric model combined with Badri’s[16,17] mold simulator data and shin’s[18] plant measurements to simulate the initial shell solidification and predict the slag consumption. However, the results from mathematic model do not completely reflect the practical outcome due to the fact that mathematic model is only the logic description and restriction of the observed phenomena. Therefore, laboratory scale experiment technique[19,20] has been developed to study the initial shell solidification. Works by Badri et al.[16,17] and Sohn et al.[21,22] have shown that the mold simulator could provide an ideal way for the study of the initial shell solidification and the lubrication of liquid mold flux. In this study, a mold simulator was used to study the initial solidification phenomenon of a low carbon steel in the continuous casting mold. Then the responding inmold hot s