结晶器电磁搅拌对高强齿轮钢大圆坯凝固行为的影响  

Effect of Mold Electromagnetic Stirring on the Gear Steel Solidification Behavior of Its Large-sized Round Casting

作　　者：王璞 肖红 沈厚发[3] 陈希青 陈列 兰鹏[1] 张家泉[1] WANG Pu;XIAO Hong;SHEN Houfa;CHEN Xiqing;CHEN Lie;LAN Peng;ZHANG Jiaquan(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083;Electromagnetic Center,Hunan Zhongke Electric Co.,Ltd.,Yueyang 414000;School of Materials Science and Engineering,Tsinghua University,Beijing 100084;Jianlong Beiman Special Steel Co.,Ltd.,Qiqihar 161041)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]湖南中科电气股份有限公司电磁中心,岳阳414000 [3]清华大学材料科学与工程学院,北京100084 [4]建龙北满特殊钢有限责任公司,齐齐哈尔161041

出　　处：《机械工程学报》2021年第2期105-111,共7页Journal of Mechanical Engineering

基　　金：国家自然科学基金资助项目(U1860111)。

摘　　要：结晶器冶金对于特殊钢连铸过程凝固与后续产品质量至关重要。以高强齿轮钢42CrMo以铸代锻?650 mm特大断面圆坯连铸生产工艺为背景,基于三维电磁-流动-传热-凝固耦合模型,研究了结晶器电磁搅拌(Mold electromagnetic stirring,M-EMS)器安装位置对大圆坯连铸结晶器冶金行为的影响。结果表明,结晶器铜管磁屏蔽效应导致搅拌器安装位置越低,搅拌效率越高;电磁搅拌可显著减轻因水口侧孔射流冲刷所造成的坯壳生长不均匀性、强化钢液过热耗散,也会不同程度地增强液面波动。搅拌器位置由330 mm下移至730 mm三个代表性工况下,钢液面最大波高差降低2.5 mm,坯壳凝固前沿最大冲刷速度增加0.069 m/s,铸流中心钢液过热耗散位置后移0.159 m,结晶器出口坯壳厚度极差降低1.1 mm。综合认为,搅拌器安装位置在弯月面下约530 mm时,既有利于控制合适的液面波动与坯壳生长均匀性以改善铸坯表面质量,也有利于因钢液过热耗散促进等轴晶形成而提高大圆坯的中心质量。Mold metallurgy is a key aspect for the control of solidification in continuous casting process and the final product quality of special steel. Based on the ?650 mm large-sized round casting process for 42 CrMo steel semi-products,the initial solidification behavior with mold electromagnetic stirrer(M-EMS) and its installation have been studied by aids of a three-dimensional coupled model for the complex magnetic, fluid flow, heat transfer and solidification behavior. The results show that the copper tube of the mold has a magnetic shielding effect, which leads to a higher working efficiency of the stirrer can only be achieved by its lower installation position. Electromagnetic stirring can reduce the jet flow impingement on the initial shell through the side-ports of the nozzle, which can enhance the superheat dissipation and intensify meniscus fluctuations. As the stirrer installation position moves downward from 330 mm to 730 mm, the maximum meniscus level fluctuation is reduced by 2.5 mm, and the maximum tangential velocity of liquid steel at solidification front is increased by 0.069 m/s, the location of zero superheat degree of the center molten steel moves down by 0.159 m, and the range of uneven shell thickness at mold exit is reduced by 1.1 mm. It is suggested that when the M-EMS is installed at 530 mm below the meniscus, it is not only beneficial to the control of the mold level fluctuation and the uniformity of the shell growth for an improved surface quality of the strand, but also beneficial to the formation of equiaxed crystal owing to the dissipation of superheat at mold exit.

关 键 词：高强齿轮钢 大圆坯连铸 M-EMS安装位置 结晶器液面波动 过热耗散 

分 类 号：TF777[冶金工程—钢铁冶金]