STUDIES OF THE BEHAVIOUR OF HIGH FREQUENCY PULSED MICRO-PLASMA WELDING ARC

In this paper, the temperature field of DC high frequency pulsed microplasma are was studiod by the infra-red photograph microcomputer image processing method. The arc and gas flow were observed by the laser display technique. The axial pressure of arc was measured by a micro-pressure measuring instrument. Results show that the axial temperature gradient in the center of hi h frequency arc is lower than that of DC arc. When the pulse frequency is over 10 kHz, the diameter of high frequency arc constricts with the frequency increment. This is more so at low current. The gas flow surrounding the high frequency arc is as stable as that in the case of DC arc. The maximum axial, pressure of the high frequency arc is higher than that of the DC arc. When the pulse frequency is over 10 kHz, the maximum axial pressure of high frequency arc decreases with the increase of pulse frequency.