Effect of submerged entry nozzle structures on liquid surface flow behavior of slab continuous casting mold
LIU Yan-bin1, TANG Hai-yan1, WANG Kai-min1, MA Yu1, SHANG Guang-hao2, ZHANG Li-ping2, ZHANG Jia-quan1
1. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China; 2. Henan Xinjinhui Stainless Steel Industry Co., Ltd., Xuchang 461000, Henan, China
Abstract：Aiming at the phenomena of mold powder involvement and warping defects in the surface of stainless steel strip products, the correlation between the flow behavior of molten steel in the continuous casting mold and the involved process parameters of submerged entry nozzle was experimentally studied based on the actual production conditions. A water model of geometrical ratio 0.65∶1 was set up based on similarity principle, and the hydrodynamic behavior of mold liquid level under different submerged entry nozzle structures and casting process parameters was evaluated and optimized. The effects of casting speed, nozzle immersion depth, side port upward angle (4°, 8°, 15°) and nozzle port shape (rectangular and inverted trapezoid) on the mold level fluctuation and surface velocity were studied experimentally. The results show that the influence of casting speed and immersion depth on liquid level fluctuation is greater than that of nozzle structure. The increase in casting speed and the decrease in nozzle immersion depth aggravate the fluctuation of liquid level in the mold obviously. With the nozzle upward angle increasing from 4° to 8° and 15°, the flow velocity on the mold surface tends to drop, and the jet flow impact depth decreases, which results in an increasing mold level fluctuation at the meniscus. It has been revealed that the appropriate nozzle structure is an inverted trapezoidal one with upward angle of 8°. At casting speed of 1.10 m/min and nozzle immersion depth of 110-120 mm with the recommended nozzle, its measured wave height of mold liquid level is 1.1-1.2 mm and the average surface velocity is around 0.103 m/s. Meanwhile, the optimized scheme is compared with the original scheme by numerical simulation, showing that the liquid level of the optimized scheme is relatively stable and the probability of the shearing slag entrapment is low.
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2022, Vol. 41 
