二冷区电磁搅拌换向周期对薄板坯中心等轴晶率的影响  

Effect of switching period of SEMS on central equiaxed crystal ratio of thin steel slabs

作　　者：王长军 刘中秋 李宝宽 WANG Changjun;LIU Zhongqiu;LI Baokuan(School of Metallurgy,Northeastern University,Shenyang 110819,Liaoning,China)

机构地区：[1]东北大学冶金学院,辽宁沈阳110819

出　　处：《连铸》2023年第5期64-70,94,共8页Continuous Casting

基　　金：国家自然科学基金资助项目(51974071);国家重点研发计划资助项目(2022YFB3705101);中央高校基本科研业务费资助项目(N2225011)。

摘　　要：在高拉速的薄板坯连铸过程中,增加等轴晶率对提升连铸坯凝固质量的提升至关重要。采用三相凝固模型对三维全尺寸薄板坯连铸过程中的流动模式和等轴晶率进行数值预测,分析了二冷区电磁搅拌换向周期对薄板坯中心等轴晶率的影响。研究结果表明,高温钢液在漏斗型结晶器内迅速凝固,结晶器出口处的铸坯凝固率达37%。当采用恒定方向电磁搅拌时,熔池内部形成上下两个环流,两者被中间聚集的过热钢液分隔,上环流核心区钢液处于过冷状态。当采用换向电磁搅拌后,二冷区会形成四涡甚至五涡的流动模式。随着换向周期的增加,等轴晶率先增加后降低,换向周期为16 s时对等轴晶率提升最明显,相较于恒定方向搅拌提升了17%,并且等轴晶相分布更加均匀。Increasing the equiaxed crystal ratio(ECR)is essential for the solidification quality of thin steel slabs dur-ing the high-speed continuous casting process.A three-phase solidification model was adapted to numerically predict the flow mode and ECR of a three-dimensional full-size thin slab continuous casting process.The effect of the switc-hing period of strand electromagnetic stirring(SEMS)on ECR was analyzed.The results showed that the molten steel solidified rapidly in the funnel-shaped mold,and the solidification rate at the mold outlet reached 37%.Two recirculation zones formed in the molten pool when the electromagnetic stirring direction was fixed,which were sep-arated by superheated molten steel.The liquid steel in the core of the upper recirculation was in a supercooled state.The flow pattern in the secondary cooling zone was composed of four or even five vortices after the stirring direction changed.ECR increased first and then decreased with the switching period of SEMS.ECR increased most signifi-cantly when the switching period was 16 s,which was increased by 17% compared with that of fixed stirring.And the distribution of the equiaxed phase became more uniform.

关 键 词：薄板坯连铸 凝固 等轴晶率 电磁搅拌 换向周期 

分 类 号：TF777[冶金工程—钢铁冶金]