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推导了一个适用于中小尺寸板状熔体表面电磁压力的计算公式。该式给出了电磁压力系数ｐ 与板厚ａ、电流频率ｆ 、以及材料的电磁参数μγ之间的准确关系。主要结果如下：（１） 当ｆ， ａ ， 以及μγ足够大， 使得板的厚度ａ 与电流集肤厚度δ的比ａ／δ＞ ２ ．２ 时， 电磁压力系数是一个常数（ ｐ ＝ １） ，电磁压力可由公式ｐｍ ＝ Ｂ２／２ μ计算。（２） 但若ｆ， ａ ， 以及μγ比较小， 使ａ／ δ＜ ２ ．２ ， 则电磁压力必须由系数ｐ 进行修正。也就是说， 电磁压力不仅由熔体表面的磁感应强度Ｂ 决定而且也由板的厚度ａ ，电流频率ｆ ， 以及材料的电磁参数μγ决定。
A formula for calculating the electromagnetic pressure on the surface of small and medium sized plate-like melt is deduced. The equation gives the exact relationship between the electromagnetic pressure coefficient p and the plate thickness a, the current frequency f, and the material’s electromagnetic parameter μγ. The main results are as follows: (1) When f, a, and μγ are large enough, the ratio of plate thickness a to δ is greater than 2. 2, the electromagnetic pressure coefficient is a constant (p = 1) and the electromagnetic pressure can be calculated by the formula pm = B2 / 2 μ. (2) But if f, a, and μγ are relatively small, a / δ <2. 2, the electromagnetic pressure must be corrected by the coefficient p. That is, the electromagnetic pressure is determined not only by the magnetic flux density B on the melt surface but also by the plate thickness a, the current frequency f, and the material’s electromagnetic parameter μγ.