Fibre laser welding for lightweight design

Two different high strength steel grades have been welded by a fibre laser to create a fillet corner joint. The purpose of this experiment is to use thinner materials of higher strength as a weight reduction strategy. The sensitivity of the welding process to the beam inclination angle, the beam position and the focal plane position were studied. High-speed imaging, process emission monitoring, measurement of the weld surface topography, mechanical testing and FE-analysis have been used to analyse the process and the resulting weld. A combined study by these methods gives a more comprehensive picture for studying the weld quality. A Bifurcation Flow Chart (BFC) has been applied as a new method to standardise and generalise the findings.