电磁振荡下薄带坯水平连铸的凝固组织  

Solidification Structure of Horizontal Continuous Casting Ribbon Billets in the Condition of Electromagnetic Vibration

作　　者：黄锦锋[1] 江建明[1] 邓康[1] 余建波[1] 任忠鸣[1] 

机构地区：[1]上海大学材料科学与工程学院上海现代冶金与材料制备重点实验室

出　　处：《特种铸造及有色合金》2009年第8期738-741,共4页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(50674066)

摘　　要：主要研究了静磁场和交流电复合产生的电磁振荡在薄带坯水平连铸上的应用。以纯Sn与Sn-10Pb合金为对象,通过热态物理模拟试验,研究金属薄带坯水平连铸的凝固组织,及其与电磁振荡强度的相互关系。结果显示,在电磁振荡作用下,纯Sn的凝固组织明显细化,并且细化效果随所施加电流的增大而增强;Sn-10Pb合金的凝固组织显示,在凝固前沿施加电磁振荡作用将显著地促进等轴晶组织的形成,使薄带坯中心出现等轴晶区,而且该等轴晶区随电磁振荡的强度增大而扩大。在低强度电磁振荡条件下,凝固组织细化和等轴晶化的原因是:电磁振荡力对金属初生晶的周期性拉伸、压缩、剪切、折弯、扭转等机械作用,使其出现断裂和剥落,增加形核数量;电磁振荡的局部搅拌作用使固/液界面前沿的温度和成分趋于均匀化,导致梯度降低,抑制了柱状晶的生长。Effects of electromagnetic vibration from static magnetic and alternative current on solidification structure of horizontal continuous casting pure Sn thin ribbon and Sn-10Pb thin ribbon were analyzed by thermal-physical experiment. The results reveal that with electromagnetic vibration,solidification structure of pure Sn is greatly refined,which is refiner with increasing in current intensity. By applying electromagnetic vibration on solidification front of Sn-10Pb alloy,creation of equiaxed grain zone in the center of thin-ribbon can be distinctly accelerated,which is enlarged with increasing in electromagnetic intensity. Electromagnetic vibration forces can increase the nucleation rates through cracking and flaking primary phase as a result of periodical mechanical effects,such as tension,compression,shearing,bending and torturing,meanwhile,magnetic vibration can restrain the growth of columnar grain by decreasing gradient as a result of the homogeneous tendency of temperature and solute at solidification front of solid-liquid interface by partial stirring,which are responsible for the refinement and equiaxed grain formation of structure in condition of low intensity electromagnetic vibration.

关 键 词：薄带坯 水平连铸 电磁振荡 凝固 

分 类 号：TG249.7[金属学及工艺—铸造] TG111.4