The effect of shielding gas composition in CO 2 laser

Abstract

In carbon dioxide (CO₂) laser—gas metal arc hybrid welding, a shielding gas is supplied to isolate the molten metal from the ambient air, suppress the laser-induced plasma, remove the plume out of the keyhole, and stabilize the metal transfer. In this study, a shielding gas consisting of helium, argon, and CO₂ was used, and its effects on the composition of the welding phenomena, such as behaviours of laser-induced plasma generation, molten pool flow, and droplet transfer in gas metal arc welding, were investigated. High-speed video observation was used to investigate the welding phenomena inside the arc regime. Consequently, helium was found to have a dominant role in suppressing laser-induced plasma; minimum helium content at a laser power of 8 kW was suggested for laser autogenous and hybrid welding. Argon and CO₂ govern the droplet transfer and arc stability. A 12 per cent addition of CO₂ stabilizes the metal transfer and eliminates undercut caused by insufficient wetting of molten metal.

Keywords

gas metal arc welding (GMAW)hybrid welding laser-induced plasma shielding gas

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The effect of shielding gas composition in CO 2 laser—gas metal arc hybrid welding

Abstract

Keywords

References