Product Code: ICA12_1505

Laser GMA Hybrid Welding for Thick Wall Applications of Pipeline Steel with the Grade X70
Authors:
Oliver Seffer, Laser Zentrum Hannover e.V.; Hannover Germany
Jasmin Lindner, Laser Zentrum Hannover e.V.; -
André Springer, Laser Zentrum Hannover e.V.; Hannover Germany
Stefan Kaierle, Laser Zentrum Hannover e.V.; Hannover Germany
Volker Wesling, Laser Zentrum Hannover e.V.; Hannover Germany
Heinz Haferkamp, Laser Zentrum Hannover e.V.; Hannover Germany
Presented at ICALEO 2012

For the joining of heavy plates hybrid processes have been established. The presented approach of one side welding of thick metal sheets combines a laser beam and two GMA welding torches in one setup. Using this hybrid process for joining high material thicknesses, manufacturing time can be significantly reduced in comparison to conventional multilayer arc welding processes. Additionally, new constructional opportunities allow savings of additive materials.
In order to benefit from these economic advantages and to make brilliant high power lasers in pipeline manufacturing useful, this hybrid process needs to run robustly for conventional welding positions as well as for common gap and tolerance ranges. The process time will be significantly decreased due to the use of disc lasers with a maximum output power of 16 kW combined with two GMA sub-processes compared with the conventional methods. For process development, steel sheets with a thickness of 23 mm of grade X70 have already been joined in flat position within a single process step over the whole thickness.
Based on these parameter studies the process limitations have been determined with regard to energy input, gap bridgeability, vertical edge offset and a depositioning of the energy sources to the welding gap. The variable applicability and the robustness of the developed hybrid process have already been approved in application oriented processes.