Laser beam submerged arc hybrid welding for thick metal sheets

摘要

The laser beam submerged arc hybrid welding technique (LB-SAW Hybrid) is a suitable welding process for joining thick metal sheets of up to 50 mm plate thickness in double-sided single pass technique. Especially in pipeline manufacturing, LB-SAW Hybrid has the potential to replace the currently used time-consuming conventional welding processes. However, despite the LB-SAW Hybrid being under constant research, the behaviour of this welding process is still not completely understood. This paper presents the latest welding results which were achieved with the LB-SAW Hybrid technique on metal sheets with a plate thickness of 40 mm. The influence of the inclination angle of the laser optics and the SAW torch regarding the penetration depth as well as the metallurgical composition of the hybrid weld metal are shown. Due to the hybrid process, it was possible to achieve an increase in the maximum reachable penetration depth of several millimetres compared to a serial process setup using the same power. Additionally, the intermixing of the alloying elements in the transition area between SAW- and laser beam-dominated weld seam area are demonstrat-ed in this contribution. Furthermore, the microstruc-ture of the hybrid weld metal is presented and discussed.