Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 17 No. 5 October 2007|
（State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Materials Science and Engineering,Dalian University of Technology, Dalian 116023, China ）
Abstract:In order to study the effect of the stirring flow on the grain diameter and solute concentration of hollow billet, the couple model of the two-phase solidification and electromagnetic field was built to simulate the solidification process of Sn-3.5%Pb hollow billet with the traveling magnetic field and rotating magnetic field. The effects of different kinds of flows on the temperature field, concentration field and grain diameter of molten metal during solidification were analysed. The results show that, there are different flow patterns in the molten metal induced by the traveling magnetic field and rotating magnetic field. Both flows can refine the grains in the hollow billet because of change of the temperature gradient and cooling rate of molten metal. The bigger the stirring velocity is, the smaller the grain diameter. Both flows can result in the macro-segregation in the hollow billet because of the non-homogeneous flows. The bigger the stirring velocity, the more serious the macro-segregation of the hollow billet. So, the stirring intensity should be controlled to acquire the high quality hollow billet.
Key words: Sn-3.5%Pb alloy; traveling magnetic field; rotating magnetic field; hollow billet; temperature field; concentration field