高频电磁悬浮熔炼的设计与实践

 介绍了高频电磁悬浮熔炼技术的原理、悬浮力和吸收功率的理论计算,悬浮的稳定性、悬浮线圈的结构设计以及影响悬浮熔炼的工艺性因素。同时,给出了这方面的研究结果。

DESIGN AND PRACTICE OF HIGH FREQUENCY ELECTROMAGNETIC LEVITATION MELTING

The Principle of high frequency electromagnetic levitation melting technique was described in terms of electromagnetic field theories.W.Brisley's and E.Fromm's levitation force formulae were modified and used to calculate the levitation forces of two typical levitation coils designed by the authors on Al and Ni samples. The authors' calculations showed that thesetwo formulae could produce results very close whith each other although the former was more accurate the qretically, and hence that the latter was much more practical in use because it required less complicated computations. E.Fromm's power absorption formula was also modified and applied to the calculations of the electrical power absorbed by Al and Ni samples in the two typical levitation coils. Besides, the levitation stability of non-magnetic and ferro-mag-netic materials was analyzed.It was concluded that non-magnetic materials were easy to levitate while ferro-magnetic materials could be levitated stably only when their temperatures exceeded their Curie points. The authors' experimental results about levitation coil design were presented as well, which indicated that cylindrical solenoid coils could provide stronger levitation forces but maintain less levitation stability than conical ones, that pancake helix stability-controlling turns could prevent the lateral drifting of the levitated samples effectively, and that regulating the distance between the stability-controlling turns and the main windings of a levitation coil could modulate the levitation stability and control the levitation height of asample. Finally discussed in the present paper were the influences of the matching among the high frequency power source and the levitation coil, power source frequencies, material properties, sample shapes and sizes as well as melting conditions on the high frequency electromagnetic levitation melting process.