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Influence of Electromagnetic Swirling Flow in Nozzle on Solidification Structure and Macrosegregation of Continuous Casting Square Billet |
Chunlei WU,Dewei LI,Xiaowei ZHU,Qiang WANG( ) |
1. Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819, China 2. School of Metallurgy, Northeastern University, Shenyang 110819, China 3. School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao 066004, China |
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Abstract During continuous casting production of square billet, the quality of steel billet is determined by equiaxed grain rate and defect grade of centerline segregation. The application of mold electromagnetic stirrer (M-EMS) can improve the quality, but it also brings some negative effects. Some researchers have attempted to make a swirling flow generated in submerged entry nozzle keep rotating in the mold to replace M-EMS. In this work, the influence of electromagnetic swirling flow in nozzle (EMSFN) on morphology of solidification structure and macrosegregation characteristics of carbon and sulfur was studied under different industrial test conditions, and the results were compared with those obtained by M-EMS. The results show that when the current frequency of EMSFN device is 50 Hz, with the current intensity increasing from 200 A to 600 A, the quantity of equiaxed grains increases gradually, while the severity of centerline segregation decreases first and then increases. The optimum value of centerline segregation was obtained when solidification structure was dominated by fine columnar crystals. Therefore, the swirling flow intensity of molten steel in submerged entry nozzle can be changed by adjusting the current parameters of EMSFN device, and thus the billets with different morphology of solidification structure and severity of macrosegregation can be obtained. Under the experimental condition, when the current parameters of EMSFN device reach certain values, EMSFN can achieve the same or even better effect as M-EMS in improving the quality of billet.
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Received: 30 October 2018
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Fund: National Key Research and Development Program of China(No.2017YFB0304400);National Natural Science Foundation of China—Joint Research Fund for Iron and Steel of Baosteel Group Co., Ltd.(No.U1560207);Program for Liaoning Innovative Research Team in University(No.LT2017011) |
Corresponding Authors:
Qiang WANG
E-mail: wangq@epm.neu.edu.cn
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