A Study on Changes of Bead Shape and Metal Transfer Mode Affected by Molten Pool Behavior for Welding Position in GMAW Process

Abstract

In gas metal arc welding, the molten pool is affected by gravity and this affects welding phenomena. This study investigated the changes in bead shape and metal transfer mode caused by the molten-pool behavior. We conducted gas metal arc welding with various welding positions. Images from high-speed camera and signals from current and voltage sensors were used to determine the differences with welding positions. Bead shapes were quantified through transverse cross-sectional bead images and image processing. Molten-pool images from the camera were analyzed through the molten-pool length and distance from the wire position. These were used to explain the differences between transverse and longitudinal cross-sectional bead images with welding positions. Changes in metal transfer based on current and voltage signals were investigated. To determine the exact change in metal transfer, the number of short-circuit transfers and spray transfers within the same time was captured by the welding position camera.