连铸过程长水口理论吹氩流量分析  

Theoretical argon flow rate analysis of ladle shroud in continuous casting process

作　　者：张育萌 程树森[1] 冯永平 李积鹏[2] ZHANG Yumeng;CHENG Shusen;FENG Yongping;LI Jipeng(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 10o083,China;Carbon Steel and Thin Plate Plant,Jiuquan lron and Steel(Group)Co.,Ltd.,Jiayuguan 735100,Gansu,China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]酒钢集团宏兴钢铁股份有限公司碳钢薄板厂,甘肃嘉峪关735100

出　　处：《中国冶金》2024年第3期75-83,共9页China Metallurgy

基　　金：国家自然科学基金资助项目(62071034)。

摘　　要：连铸过程水口间接缝容易吸入空气,使得钢液二次氧化。生产中采用长水口吹氩来防止空气吸入,但吹氩流量控制不当会导致铸坯缺陷。水口吸入空气是由于水口内部压力低于大气压,目前水口吹氩流量控制与工艺参数调整并未建立联系。基于连续性方程和伯努利方程建立钢包到中间包的质量-能量守恒数学物理模型,研究长水口钢液流动时水口内压力分布,总结不同出口条件及吹氩流量下水口内流体分布状态,同时计算不同条件下的理论吹氩流量;探究浇注时间、拉坯速度、滑动水口及长水口直径、长水口浸入深度、吹氩流量对水口内压力分布的影响。研究发现,提高拉速、增加长水口浸入深度、减小滑动水口和长水口直径以及提高水口吹氩流量有利于减小水口内负压;当提高拉速、增加长水口浸入深度或增大水口直径时应当加大吹氩流量;使用喇叭型长水口可以降低出口钢液速度,其内部压力小于直筒型长水口,吹氩时其水口出口钢液速度增加量比直筒型长水口小。研究结果为制定长水口吹氩量提供了理论基础。In the continuous casting process, air can enter the nozzle through the gap between ladle shroud and collector nozzle and cause the molten steel to re-oxidize. Argon injection is used at the shroud to prevent air suction, but improper control of the argon flow rate will lead to defects in the billet. The air suction is due to the internal pressure of nozzle being lower than atmospheric pressure. At present, the control of nozzle argon flow rate is not related to the adjustment of process parameters. A mathematical and physical model of mass-energy conservation from ladle to tundish was established. The model was based on the continuity equation and the Bernoulli equation. The pressure distribution in the nozzles during the flow of molten steel in ladle shroud and the fluid distribution in the ladle shroud under different outlet conditions and argon flow rates were summarized. The effects of teeming time, casting speed, the diameter of slide gate and ladle shroud, immersion depth of ladle shroud, and the effect of argon flow rate on pressure distribution in the nozzles were investigated, and the theoretical argon flow rate under different conditions was calculated. The results show that increasing the casting speed, the immersion depth of the ladle shroud or the argon flow rate, and reducing the diameter of the slide gate or ladle shroud are beneficial to reduce the negative pressure in the nozzle. When increasing the casting speed, the immersion depth of the ladle shroud and the diameter of the nozzle, the argon flow rate should be increased. The use of trumpet ladle nozzle can decrease the outlet rate of molten steel, which has smaller pressure than the conventional ladle shroud, and more slowly increases the outlet rate of molten steel than that of the conventional ladle shroud in argon injection. The research results provide theoretical basis for determining the argon flow rate in the ladle nozzle.

关 键 词：长水口 伯努利方程 连续性方程 压力分布 吹氩流量 

分 类 号：TF777[冶金工程—钢铁冶金]