电磁铸造移动磁场发生器磁场分布规律及其作用分析

研究了用于电磁铸造的移动磁场发生器上磁场强度变化及其对金属产生的力的作用.结果表明,磁感应强度分量By和Bz的变化趋势相反.By的存在使金属流动充型过程中产生表面凹坑型缺陷,Bz明显提高金属液流动速度,而在提高充型能力的同时,会使金属液流前端截面减小而形成反向充填,引发冷隔缺陷.铁磁性上模可以减弱By、增强Bz,提高表面质量.金属在移动磁场中受到的力与其投影面积有关,而且存在临界投影面积,小于该临界值后,电磁力不足以拉动该金属.

Magnetic Field Distribution of the Traveling Magnetic Field Generator Used for Electromagnetic Casting and its Action on the Melt

Magnetic flux density distribution of traveling magnetic field generator used for electromagnetic casting and its action on the melt were investigated. The results show that magnetic flux density in z and y direction (B z and B y) varies inversely.Existence of B z results in pit defects in surface during mold filling.Although B z can obviously accelerate the melt flow velocity to improve the ability to filling mold, section of the melt front is decreased to take converse filling mold, resulting in cold shut defects. The surface quality can be improved by ferromagnetic up-mold via enhancing B z and weakening B y. The pulling force exerted on metal from magnetic field is related to the projective area of metal on the inductor. The metal cannot be moved even in the existence of electromagnetic force with the projective area less than a critical projective area.