Weld Pool Oscillation as a Tool for Penetration Sensing during Pulsed GTA Welding

摘要

This paper deals with weld pool oscillation duringpulsed gas tungsten arc (GTA) welding of unalloyed steel. Experiments were carried out in which the weld pool was triggered into oscillation during both the base time and the pulse time by short current peaks, superimposed on the pulsed welding current. The arc voltage was continuously measured during welding and the oscillation frequency spectrum was calculated on-line from the voltage variations by means of Fast Fourier Transform analysis, using a computer program. It was found that the obtained frequency distribution gives direct information about the penetration of the weld pool and can serve as a basis for sensing and in-process control of weld penetration.