In situoptical measurement of liquid drop surface tension in gas metal arc welding

Abstract
The surface tension of detached liquid drops in pulsed gas metal arc welding was determined in situ from the period of the prolate-oblate oscillations initiated by the detachment event. The oscillating drops were imaged by an optical shadowgraph technique utilizing laser illumination. Images obtained during the welding process were recorded with a high-speed video camera and stored for subsequent analysis. For 4047 aluminium alloy wire, surface tension values in the range 0.54-0.7 were obtained for various droplet sizes.