Control of TIG Arc Behavior by YAG Laser and Development of Laser Weaving Method

Abstract

  TIG welding process is often used to join thin metal plates because of the stability of arc compared with the other arc welding processes. However, the temperature of the tungsten electrode of the TIG welding torch sometimes increases and oxidation occurs during welding process. Therefore, the electrode tip is consumed considerably, and the arc stability tends to decrease with welding time. Accordingly, it is important to administrate the electrode tip condition in order to keep the welding process stable. On the contrary, the laser beam has extraordinary stability and directivity because of the nature of the light beam. Therefore, the authors have proposed a new process to stabilize and control the unstable TIG arc by the laser beam. In this study, in order to discuss the mechanism of arc behavior control by the laser beam irradiation into weld fused metal, the temperature distribution of the weld was calculated by heat conduction analysis using the finite element method (FEM). Then the control of the arc behavior in TIG welding of thin metal plates using the YAG laser beam with relatively low power was experimentally investigated. Furthermore, butt welding experiments of SUS304 stainless steel plates were performed, and the effectiveness of the new process to oscillate TIG arc using the laser weaving method was confirmed.