Defects and process tolerances in welding of thick plates Available to Purchase

Laser welding and laser-GMA-hybrid welding using 8 kW, 20 kW and 30 kW fiber lasers was investigated. Steel plates from low alloyed steel (e.g. pipeline steel X65) having a thickness of 16 mm up to 28 mm were joined under various conditions. Single layer laser-GMA-hybrid welding as well as multi layer hybrid welding were investigated for different seam preparation types. Butt welds and different types of Y-welds have been tested. The air gap and the edge misalignment have been varied intentionally to investigate the process window as it is also intended to use the process in rough environment. Different types of phenomena which reduced the efficiency of the process (measured by the welding depth) were detected. In laser welding a significant influence of the focal length was seen, in which a short focal length reduced the penetration depth strongly. Multi layer hybrid welding resulted in pore formation while single layer hybrid welding showed reasonable good results.