脉冲磁场下电磁力特性研究:凝固实验

On the Characteristics of Pulsed Electromagnetic Force:Solidification Experiment

采用低熔点金属伍德合金研究了工频脉冲磁场对金属液面波动行为的影响规律:工频脉冲磁场的周向电磁力搅拌熔体使其形成环状涡流;而径向电磁力在其表现为压力作用时使熔体在中心形成圆形液柱,表现为拉力作用时使熔体在中心形成圆形漩涡.另外,采用Sn-20%Pb合金研究了工频脉冲磁场对铸坯质量的影响:工频脉冲磁场的作用不仅使Sn-Pb合金的微观组织明显细化,而且使铸坯的表面质量得到明显改善.在本实验条件下,当脉冲放电频率为3.9和6.6 Hz时,金属熔体的液面发生共振运动,加速了熔体内的流动,从而增强了脉冲磁场的细化效果.

With the low-melting-point Wood＇s metal used,how the PMF（pulsed magnetic field） affects the fluctuation behavior of melt meniscus in PMF was investigated,where the melt was stirred with the peripheral electromagnetic force to form a vertex,while the radial electromagnetic force formed a liquid cylinder and vertex at the central part of melt if the force played a role of compression and tension,respectively.Moreover,the Sn-20wt% Pb alloy was applied to investigating the effect of the PMF on the quality of billet.The results showed that the microstructure of the alloy is obviously refined with the surface quality of billet improved greatly.Also,under the experimental conditions,when the pulsed discharge frequency is 3.9 or 6.6A4!Hz,a resonance occurs on the surface of molten metal so as to accelerate the flowability in the melt,thus enhancing the grain refining effect of the PMF.