Comparative analysis of GMA, laser and laser-GMA hybrid welding

Abstract

Laser welding and laser gas-metal arc (GMA) hybrid welding are being increasingly used in heavy industry. It is very typical that a product earlier welded by conventional arc welding needs changes to its design when laser or hybrid welding processes are considered. This presentation is based on a master’s thesis, the aim of which was to provide guidelines for structural designers. The material used in the welding tests was S355K2 (EN 10025). The joint geometry was butt joint and the material thicknesses were 4 and 6 mm. Groove preparations were made by laser cutting and machining. Welding tests were conducted using a Rofin Sinar diode pumped Nd:YAG laser with maximum 4.4 kW laser power and a Kemppi Pro4200 Evolution GMA power source. The quality target for the welding was class B, in accordance with EN ISO 13919-1 and EN ISO 5817. The welds were tested destructive and non-destructive in accordance with EN-ISO 15614-1/11. The results show that laser-GMA hybrid welding is more robust and has a higher welding speed than conventional GMA and laser welding. The average weld quality in laser-GMA hybrid welding and GMA welding is better than the average weld quality in laser welding.