Online prediction method of slag entrainment in mold based on numerical simulation
ZHOU Hai-chen1,2,3, LIU Guo-liang1,2,3, LI Hai-bo1,2,3, DENG Xiao-xuan1,2,3, JI Chen-xi1,2,3, LUO Yan-zhao1,2,3
1. Research Institute of Technology, Shougang Group Co., Ltd., Beijing 100043, China; 2. Beijing Key Laboratory of Green Recyclable Process for Iron and Steel Production Technology, Beijing 100043, China; 3. Beijing Engineering Research Center of Energy Steel, Beijing 100043, China
Abstract：When the mold flux is entrained in the molten steel, it is easy to be captured by the growing solidified shell. Finally, the surface defects caused by the mold slag entrainment will be formed on the cold rolling sheet,which seriously deteriorate the quality of steel products. The phenomenon of slag entrainment in the mold is effected by the molten steel composition,temperature,flow pattern,and argon flow rate. The velocity of molten steel at the top surface of mold is an important parameter that reflects whether slag entrainment occurs at the steel-slag interface. However,the maximum velocity of molten steel at the top surface under different casting speeds, argon flow rates,and submergence depths of SEN cannot be predicted online in the actual casting process. An online prediction method of slag entrainment in the mold based on the numerical simulation of multiphase flow in the slab continuous casting mold was proposed. First,a 3D mathematical model of the multiphase flow was built and the behavior of molten steel flow with different casting speeds,argon flow rates, and submergence depths of SEN was simulated. Then,the calculated maximum velocity of molten steel at the top surface was fitted and the prediction equation of the maximum velocity under the fixed mold section was obtained. Finally,the accuracy of the method was verified by nail board measurements in a steel plant. The results shown that the speed of molten steel on the top surface had a trend of increasing first and then decreasing along the mold width and had a maximum value at the 1/4 mold width under different casting parameters. The speed had a larger value near the narrow face and the SEN under the smaller and larger casting speed,respectively. It had a larger value near the SEN and the narrow face under the smaller and larger argon flow rate,respectively. With the increasing of submergence depth of SEN,the speed varied small near the SEN and the narrow face. Based on the fitted equation of the molten steel velocity,the online prediction of slag entrainment in the mold was realized through comparing the maximum speed of the molten steel with the critical speed of slag entrainment at the steel-slag interface.
周海忱, 刘国梁, 李海波, 邓小旋, 季晨曦, 罗衍昭. 基于数值模拟的结晶器卷渣在线预测方法[J]. 钢铁, 2022, 57(8): 103-110.
ZHOU Hai-chen, LIU Guo-liang, LI Hai-bo, DENG Xiao-xuan, JI Chen-xi, LUO Yan-zhao. Online prediction method of slag entrainment in mold based on numerical simulation[J]. Iron and Steel, 2022, 57(8): 103-110.
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