Study on Suppression of Bead-Meandering of Pure Ar-MIG Arc Welding using External Magnetic Field

Gas metal arc welding is typically performed by adding a minimal amount of oxygen to the shielding gas to protect the arc; this affects the toughness of the welded joints. This can be avoided by employing pure argon gas as the shielding environment. However, this leads to beadmeandering because the cathode spot on the base metal moves past the molten pool in search of O2 outside the shielding gas. In this study, we propose a method for controlling the cathode spot by using an external magnetic field for suppressing bead-meandering, the proposed method does not require changing the electrode wire or the shielding gas. Horizontal and vertical external magnetic fields are obtained when using DC and AC external magnetic fields, respectively. A bead-on-plate welding experiment is performed by applying an external magnetic field and using pure Ar as the shielding gas. The effect of the external magnetic field on the stability of the arc, shape of the bead, and penetration depth is evaluated, and the, effectiveness of pure Ar-MIG arc welding using external magnetic field is examined.