Contribution to the fatigue assessment of laser welded joints

AbstractLaser welded components are widely used in automotive industry enabling high quality joints with minimized heat energy input. This paper contributes to the feasible fatigue levels of disc laser welded joints made of 20MnCr5 and GJS620 using different process parameters. The fatigue behaviour of similar joints made of 20MnCr5 was also studied for two different contact conditions. The influence of the heterogeneous start and stop pilot region of the laser beam to fatigue life is also discussed. Accompanying fracture analysis detected the spot of technical crack initiation at the most stressed root surface. A high process quality for the laser welded joints was confirmed by examining both metallographic sections and the surface topography. Structural weld simulation work was performed to elucidate the local differences between the continuous seam and the overlapping laser weld pilot regions. Investigations showed that the notch stress approach with an effective radius of 0.05mm lead to S/N-curves which generally matched the standard recommendations regarding fatigue