【作者】 陶应龙；

【导师】 程晓敏；

【作者基本信息】 武汉理工大学 ， 材料学， 2004， 硕士

【摘要】 铝合金材料具有质量轻、强度高、耐腐蚀、耐疲劳等优异性能，在航天航空、机械制造、IT业等领域得到了越来越广泛的应用。然而，铝合金材料中的金属夹杂物和非金属夹杂物等缺陷，严重影响材料质量和使用安全。传统的过滤净化技术虽然能有效地清除微米级大小的夹杂物，但存在过滤效率随时间下降的问题。电磁净化方法，可以从根本上克服上述方法的不足。电磁净化方法的基本原理是液态金属中杂质颗粒的电导率与金属液的电导率不同，夹杂颗粒在电磁场中受到电磁力的作用而产生定向迁移，与金属液分离，从而达到金属净化的目的。本文在实验研究基础上，对影响电磁净化效果的工艺参数进行了分析，为提高电磁净化效率提供理论依据。 本文在电磁流体力学基本理论的基础上，运用积分方程法建立了分离器气隙的电磁场数学模型。对磁场的分布情况进行了模拟计算，并对计算结果进行了分析讨论，实验结果表明计算结果与实际测量结果基本一致。气隙中磁场分布是稳恒的，可以用来分离铝熔体中的夹杂颗粒。 实验表明：熔体温度显著影响电磁净化效果。当熔体温度过低时，粘度大，流动性差，不易于杂质颗粒流动分离；当熔体温度过高时，熔体的导电率降低，杂质颗粒受到的电磁力或电磁挤压力减小，分离效果则下降。 增大磁场强度能够有效地提高铝熔体的净化效率。但过分增大磁场强度可能导致涡流的产生，分离的杂质颗粒又重新进入熔体，从而降低净化效率。 通过增大外加直流电流和延长保温静置时间，可以提高电磁净化效率。实验结果表明，杂质粒径越大，其所受到的电磁力或电磁挤压力就越大，迁移速度也越大，也就越易于从铝熔体中分离出来。更多还原

【Abstract】 With the good property of lightweight, higher intensity, resisting corrosion, resisting fatigue, the aluminum alloy material is widely used in the field of aircraft manufacturing, car product, mechanical manufacturing and IT product. However the metallic and nonmetallic inclusions in the aluminum alloy will affect the property of quality and safety. Tradition separation methods have low removal efficiency to the time and can’t remove the small dimension inclusions. The new method of electromagnetic separation can overcome the faults. Its basic theory, the inclusions and aluminum melt have different electric conductivity, so different force will be exerted on them. The force exerted on inclusions will remove them from the aluminum melt. In this paper we will study the different processing parameters of electromagnetic separation from aluminum melt according to experiments and give the study results.In this paper mathematics model of electromagnetic field for separator gap was built by integral equation according to the theory of electromagnetic hydrodynamics. The distributing of electromagnetic field in separator gap was calculated and the results were discussed. The calculating results and measuring results are almost same. The electromagnetic field in separator gap is steady and can remove the inclusions in the aluminum melt.The temperature of aluminum melts remarkably affects the efficiency of electromagnetic separation. From the experiments we know that under the low temperature the viscosity of aluminum melts was high and the melts flow difficultly. Thus the inclusions in aluminum melts are difficult to be separated. If the temperature of aluminum melts was high, the conductivity of aluminum melts will reduce and the electromagnetic force or the electromagnetic repulsive force exerted on inclusions will reduce. Thus it will also reduce the efficiency of electromagnetic separation.The efficiency of electromagnetic separation will be improved by increasing the intensity of magnetic field influence. In fact it is difficult to get strong electromagnetic field. In the meantime if the magnetic field is a variable, there will be a agitation in the aluminum melt. The separated inclusions will go into the aluminum melt again. It will lead to low efficiency of separation.From the experiments, we know that increasing the value of DC current and long processing time can make for higher separation efficiency in the same condition. With the increasing volume of inclusion, the electromagnetic force or the electromagnetic repulsive force exerted on inclusion and the velocity of inclusion will also increase. The inclusions can be easily separated from the aluminum melt.更多还原