镁锭坯金属内套结晶器电磁铸造工艺数值模拟

针对传统低频电磁铸造工艺中,镁合金熔体与保温帽的高反应性,严重影响了生产效率与产品质量的问题,通过数值模拟方法研究了采用全金属内套结晶器时电磁场参数对电磁场分布及其对镁合金熔体作用效果的影响.结果表明:电磁频率同时影响洛伦兹力大小与方向,低频电磁作用深、焦耳热小、熔体受约束作用弱、对流作用强、液穴浅;高位线圈有利于提高电磁作用深度,但也加强了熔体表面的外推速度与强度;高电阻率内套具有较小的焦耳热.

Numerical Simulation of LFEC Process of Magnesium Billets with a Metal Bushing Mold

It was found that the mold with hot top was unsuitable for magnesium ingots in the DC low-frequency electromagnetic casting (LFEC)process, because of the high reactivity between hot top and magnesium melt which will affect greatly the productivity and quality of the billets.The effects of the electromagnetic (EM)parameters on the EM distribution and how they affect the magnesium melt were investigated by numerical simulation with a metal bushing attached to the mold. The results indicated that EM frequency affects not only the magnitude of Lorentz force but also its direction. In the low-frequency EM field, the long penetration depth, low Joule heat,weak magnetic confinement, strong convection and shallow melt trap can all be achieved. When the excitation coil is held at high level, the EM penetration becomes deeper with the melt pushed outwards more rapidly, and the Joule heat in the high-resistivity bushing becomes lower.