Laser beam and laser‐GMAW‐hybrid welded joints made of high‐strength fine‐grained structural steels

In the case of fine-grained structural steels with the currently highest nominal yield strengths of up to 1300MPa, the execution of high-quality welded joints represents a particular challenge. Innovative welding processes, such as laser beam and laser hybrid welding, show high application potential, but have only rarely been used due to a lack of experience so far. Part 1, therefore, presents a weld characterisation carried out on four different materials (S960MC, S1100M, S1100QL, S1300QL) and two welding process variants (laser beam welding without filler metal, laser-GMAW-hybrid welding). The investigations of butt welds include visual, dye penetration and X-ray tests as well as transverse tensile tests and hardness field measurements. The weld zones show remarkably small dimensions and only moderate softening, which is particularly concentrated in the tempering zone. Exceptions are the joints of the S1100M, where no softening is observed in the tempering zone.