Product Code: ICAL08_1004

Defects and Process Tolerances in Welding of Thick Plates
Authors:
Frank Vollertsen, BIAS; Bremen Germany
Stefan Gruenenwald, Bias; Bremen Germany
Presented at ICALEO 2008

Laser welding and laser-GMA hybrid welding using an 8 kW fiber laser was investigated. Steel plates from low alloyed steel (e. g. pipeline steel X65) having a thickness of 10 mm up to 20.5 mm were joined under various conditions. Single layer laser welding and laser-GMA hybrid welding as well as multi layer hybrid welding were investigated for different seam preparation types. Butt welds and different types of single-V butt welds with broad root face have been tested. The gap and the edge misalignment have been varied intentionally to investigate the process window as it is intended to use the process in rough environment also. 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 welding resulted in pore formation while single layer (hybrid) welding showed reasonable good results.