The influence of plate thickness on the penetration in GTAW has been investigated and a front pool width penetration control approach has been studied, which controls the penetration under the variation of plate thickness. A theoretical heat flow model for a plate of a finite thickness has been utilized to investigate the relationship of the pool widths on both sides. A penetration control system for autogenous GTA welding has been utilized which uses a coaxial weld pool imaging system and computer vision processing to sense the width of the GTA weld pool. Empirical results show the good performance of this penetration control approach in the presence of variations in a joint root thickness of 1 mm (0.04 inch) to 3 mm (0.125 inch).
