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本文介绍了一种新的焊接方法——真空磁压缩等离子弧焊接。真空磁压缩等离子弧是将低真空中的自由电弧用与电极同轴向的磁场压缩后获得的。实验表明,随着气压的降低,自由电弧会越来越扩展,弧根区的电流密度越来越低,直至产生“旁弧”,不能稳定燃烧而熄灭。而且这种低真空自由电弧难以用和普通等离子弧相似的机械方法压缩。采用轴向磁场可以有效地压缩真空电弧。磁压缩的效果随气压的降低趋于明显,气压低于1.33×10~2Pa 时,几十分之一特斯拉(T)的磁场就可获得略粗于电极、上下直径近似相等的弧柱,我们称之为真空磁压缩等离子弧。使用真空磁压缩等离子弧作为热源,可以焊接一般金属和活泼金属,其熔透工件的能力可超过大气氩弧,并可用调节磁场强度的方法,调节电弧的能量分布。与常规氩弧焊、等离子孤焊、电子束焊相比,真空磁压缩等离子弧焊接有其独到的优点,可望在不久的将来获得广泛的应用。
This article describes a new welding method - vacuum magnetic compression plasma arc welding. Vacuum Magnetic Compression Plasma arc is obtained by compressing a free arc in a low vacuum with a magnetic field coaxial with the electrodes. Experiments show that as the barometric pressure decreases, the free arc will expand more and more, and the current density in the arc root zone will become lower and lower until a “para arc” occurs, which can not be stabilized and extinguished. Moreover, such a low vacuum free arc is difficult to compress by mechanical means similar to ordinary plasma arcs. The use of axial magnetic field can effectively compress the vacuum arc. The effect of magnetic compression tends to be noticeable with the decrease of gas pressure. When the gas pressure is lower than 1.33 × 10 -2 Pa, a few tens of Tesla (T) magnetic fields can obtain arcs slightly thicker than the electrodes and have approximately the same diameter up and down , We call it vacuum magnetic compression plasma arc. The use of a vacuum magnetic compression plasma arc as a heat source allows for the welding of metals and live metals in general and the ability to penetrate the workpieces over atmospheric argon arcs and to adjust the energy distribution of the arcs by adjusting the magnetic field strength. Compared with conventional argon arc welding, plasma arc welding and electron beam welding, vacuum magnetic compression plasma arc welding has its own unique advantages and is expected to be widely used in the near future.