An update on joint characterization of three sheet friction stir lap welds (FSLW) in three aluminum alloys (7xxx, 5xxx, and 6xxx) for automotive assembly application is presented. Welding speed of 0.3-2.9m/min was used with pin length >5mm with the aim to reduce upturn hooking on the retreating side and avoid wormhole defect on the advancing side. Joints were also made in to enable T peel and U peel testing. Stitch welds were used to understand effects of weld length and ramp length on T peel performance. Hat sections were joined for 3-point bending and axial crush testing and tested with promising results. Several key issues that require further investigations are identified including flash management near the trim edge, weld quality with limited clamping, tool failures at speeds greater than 0.5m/min, and propensity of incipient melting for 7xxx stack-up.
Published: May 12, 2021
Citation
Upadhyay P., H. Das, and D.D. Graff. 2021.Three Sheet Al alloy assembly for automotive application. In Friction Stir Welding and Processing XI, The Minerals, Metals & Materials Series, edited by Y. Hovanski, et al. Cham:Springer.PNNL-SA-157267.doi:10.1007/978-3-030-65265-4_2