Research and application on high casting speed technology of low-carbon steel MCCR line
WANG Hao1, WANG Guo-lian1, MA Shuo1, WANG Sheng-dong1, TANG Ping2, LIU Yan-qiang3
1. Steel Rolling Department, ShougangJingtang Iron and Steel Co., Ltd., Tangshan 063200, Hebei, China; 2. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China; 3. Manufacture Division, ShougangJingtang Iron and Steel Co., Ltd., Tangshan 063200, Hebei, China
Abstract：Through statistics and analysis of field data, it is concluded that the main factors limiting the increase of continuous casting speed of low-carbon steel for thin slab in MCCR line are cold teeth in thermal image and liquid level fluctuation in the mold. The causes of cold teeth and level fluctuation were studied, and effective control measures were proposed. The research results show that cold teeth thermal image in the mold are related to the solidification shrinkage characteristics of the mold meniscus, and affected by the thickness of mold copper plate, carbon equivalent, casting speed and mold powder. It is reflected that there are depression or crack defects on the slab. The optimal parameter combination should be formed by reasonable matching to reduce the risk of steel leakage caused by cold teeth. When the thickness reduction of the mold copper plate is within 6.7%, the primary cold water maintains the original design value; when the thickness reduction of the mold copper plate is 6.8%-11.1%, the water flow of primary cooling shall be reduced by 10% at the speed more than 4.0 m/min; when the thickness reduction of the mold copper plate is 11.2%-15.6%, the water flow of primary cooling shall be reduced by 18% at all speeds, and high alkalinity B-type mold powder shall be used at the same time. Aiming at the problem of mold level fluctuation under high speed, the effects of submerged nozzle immersion depth, casting speed, mold section width and electromagnetic braking on the flow field and temperature field in the mold were studied through numerical simulation. The reasonable configuration of electromagnetic braking current under different speeds and sections at high speed was obtained. When the speed reaches 5.5 m/min, the maximum speed of mold level was still less than 0.3 m/s. Through the application of the above research, the cold teeth problem of the mold has been effectively alleviated, the maximum speed of 110 mm thin slab has reached 5.8 m/min, the mold level fluctuation is controlled within ±1 mm, the thickness of mold liquid powder layer is maintained at 8-10 mm, the heat flow of the mold is stable, and the smooth and stable production at high speed has been realized.
王皓, 王国连, 马硕, 王胜东, 唐萍, 刘延强. MCCR产线低碳钢高拉速技术研究与应用[J]. 中国冶金, 2022, 32(12): 88-97.
WANG Hao, WANG Guo-lian, MA Shuo, WANG Sheng-dong, TANG Ping, LIU Yan-qiang. Research and application on high casting speed technology of low-carbon steel MCCR line[J]. China Metallurgy, 2022, 32(12): 88-97.
Suzuki Mikio,Suzuki Makoto,Nakada Masayuki. Perspectives of research on high-speed conventional slab continuous casting of carbon steels[J]. ISIJ International,2001,41(7):670.
[4]
LI Lin-ping,WANG Xin-hua,DENG Xiao-xuan,et al. Application of high speed continuous casting on low carbon conventional slab in SGJT[J]. Steel Research International,2014,85(11):1.
LI Lin-ping,WANG Xin-hua,DENG Xiao-xuan,et al. Process and quality control during high speed casting of low carbon conventional slab[J]. Journal of Iron and Steel Research International,2015,22(S1):1.
[7]
Kromhout J A. Mold powder development for continuous casting of steel[J]. Transactions of the Indian Institute of Metals,2013,66(5/6):587.
LIU He-ping,YANG Chun-zheng,ZHANG Hui,et al. Numerical simulation of fluid flow and thermal characteristics of thin slab in the funnel-type molds of two casters[J]. ISIJ International,2011,51(3):392.
2022, Vol. 32 
