M. Q. Johnson, P. Burgardt, Los Alamos National Labratory, Los Alamos, NM; N. Ames, EWI, Columbus, OH

Summary: This study clearly demonstrates that surface tension induced fluid flow is the predominant mechanism causing increased penetration when using oxide based fluxes and the GTAW process. A hypothesis was presented to explain why flux effectiveness decreases when welding thin plate (< 1 mm) and when welding thick plate (> ~ 20 mm).