Design method of electromagnetic field applied to Al-alloy electromagnetic casting

The electromagnetic pump imposes the electromagnetic motive force (Lorentz force) on the liquid metal directly and makes it move along the definite direction by using the function of electric current and magnetic field in the conducting fluid. Compared with the traditional die casting, the system of counter-gravity casting can effectively control the speed of filling to make Al-alloy liquid fill steadily by adjusting controlled-current. So the foundry defects can be decreased or avoided effectively by this system. Based on the theory of electromagnetic pump, the design method of electromagnetic field in electromagnetic pump was investigated emphatically. The rule of magnetic induction intensity B influenced by the divided electromagnet airgap's size was founded. Furthermore, the empirical formula of magnetic induction intensity B in a magnetic airgap for an open magnet in the saturated state was deduced by mathematics regression analysis. Counter-gravity casting applied to the Al-alloy electromagnetic filling was developed with this method. Besides, the electromagnetism filling counter-gravity casting process of the turbo-charge blade wheel was also fixed. The eligibility rate of blade wheel produced by such technique can be increased to 98%. The casts have compact structure and excellent capability.

铝合金电磁充型低压铸造电磁场设计方法

根据电磁泵原理,着重对电磁泵中电磁场的设计方法进行了研究,获得了分体式电磁铁磁隙宽度和磁极结构对磁隙中磁感应强度B的影响规律。结果表明,磁感应强度B与铁芯横截面积S的平方根S、磁感应强度B的自然对数lnB与磁隙宽度δ以及与铁芯的中心线长度L0和铁芯横截面积S的平方根之比L0/S～(1/2)均成线性关系。利用数学回归分析的方法,推导出开口磁铁在饱和阶段磁隙间的磁感应强度B的经验计算公式。

铝合金扁锭电磁连铸结晶器内磁感应强度的分布

用特斯拉计测量了电磁连铸铝合金扁锭结晶器内的磁感应强度。实验结果表明,结晶器内同一高度平面上磁感应强度在角部处最大,短边中心次之,长边中心磁场较短边中心处稍弱,平面中心处最小;沿高度方向上各点磁感应强度在感应线圈高度的1/2处附近达到最大值。感应线圈上表面的磁场较小,中心平面内的磁场较大,磁感应强度的大小和分布情况能够满足软接触电磁连铸的要求。中心平面的磁场分布规律较好而且磁场分布均匀,这样更有利于软接触的实现。各点的磁感应强度均随电流的增大而增大。