Effects of Active Gases on Droplet Transfer and Weld Morphology in Pulsed-Current NG-GMAW of Mild Steel

Abstract The current research of narrow-gap gas metal arc welding (NG-GMAW) primarily focuses on improving the sidewall fusion and avoiding lack-of-fusion defect. However, high cost operation difficulty methods limit industrial application. In this study, small amount active gases CO 2 O were added into pure argon inert shielding to improve weld formation pulsed-current mild steel. Their effects droplet transfer behavior investigated. A high-speed visual sensing system was utilized observe process morphology. When proportion , being gas, changes from 5% 25%, mode pulsed spray streaming projected transfer, while it remains when 2% 10% is added. Both are favorable stabilizing process. even more effective than . likely cause slags surface, can appearance in some sense. surface concavity NG-GMAW greatly influenced by addition but width penetration almost keep constant. This study proposes a new method which beneficial bead stability.