A Study On Effect Of Electromagnetic Vibration On The Collision And Agglomeration Of Non-metallic Inclusions

A new method to remove the fine inclusions from the alloy melts isproposed in this paper, which is agglomerating the fine inclusions into largeclusters or particles that can be easily separated with the application ofelectromagnetic vibration. The primary silicon particles in Al-20%wtSi alloy areregarded as nonmetallic inclusions. Electromagnetic vibration is induced bysimultaneous application of an alternating electric field and a stationarymagnetic field with an experimental apparatus. The collision and agglomerationbehavior of primary silicon particles in Al-Si molten alloy under the effect ofelectromagnetic vibration and the influence law of the collision andagglomeration behavior of silicon particles affected by the parameters ofelectromagnetic vibration are investigated by experiment. The mechanism ofcollision and agglomeration behavior of primary silicon particles under theeffect of electromagnetic vibration is studied based on experimental results.The research discovers that:(1) the application of either the stationarymagnetic field or alternating electric field alone cannot cause agglomeration ofthe silicon particles in Al-Si alloy melt. Only the application of electromagneticvibration during the solidification process can cause the silicon particles toagglomerate into clusters.(2) The collision probability of silicon particles inAl-Si alloy melt is highly improved with the application of electromagneticvibration. In order to reduce the surface energy, the silicon particles are inclinedto agglomerate together after collision.(3) With the increase of the alternatingelectric current of electromagnetic vibration, the number of silicon particles in acluster and the sizes of the clusters decrease and the clusters become morecompact. With the increase of the magnetic field of electromagnetic vibration,the silicon clusters have the same changing trend. But with the increase of thefrequency of electromagnetic vibration, the compact degree does not changevery much.(4) With the increase of electromagnetic force, the velocity of thesilicon particles in Al-Si alloy melt increase and the silicon particlesagglomerate into compact clusters after collision. When the electromagnetic force is small, the main effect of electromagnetic vibration is prompting thesilicon particles to collide and agglomerate. When the electromagnetic force islarge, the effect of electromagnetic vibration will not only be prompting thesilicon particles to collide and agglomerate, but also include detaching thesilicon particles from agglomeration clusters. Therefore the number of siliconparticles in clusters and the sizes of clusters will decrease with the increase ofelectromagnetic force.The research indicates that: electromagnetic vibration has an effect ofprompting the non-metallic inclusions in Al-Si alloy to collide and agglomerate.The fine inclusions in Al-Si alloy melts can agglomerate into large and compactclusters or particles with the application of electromagnetic vibration. The sizesand the compact degree of inclusion clusters can be controlled by adjusting theparameters of electromagnetic vibration. Therefore the method to remove thefine non-metallic inclusions from the Al-Si alloy with the application ofelectromagnetic vibration proposed in this paper is very feasible.