Suppression of arc wandering during cold wire-assisted pulsed gas metal arc welding

The use of pulsed gas metal arc welding (P-GMAW) is fundamental to applications were versatility and control of heat input are required during deposition. However, when welding using pure argon shielding gas, a drawback is the instability derived from wandering of the cathode spots on the weld pool. This work investigates an alternative to weld steels using pure argon shielding gas with cold wire pulsed gas metal arc welding (CW-P-GMAW). A mechanism for enhanced stability is revealed in CW-P-GMAW, related to the migration of cathode spots to the cold wire which prevents the cathode spots from wandering around the weld pool. The migration of cathode spots is likely related to charging of oxides on the cold wire surface by ions formed in the arc plasma. The enhanced arc stability smooths the shape of bead profile, since wandering of the arc due to cathode motion is suppressed.