Benefits of very high feed rates for laser beam welding of AlMgSi aluminum alloys

The present paper shows that laser beam welding of AA6016 aluminum sheets without filler wire but at high feed rates in the order of several tens of m/min is beneficial with respect to depth fluctuation, pores, and centerline cracks. Welds in the overlap configuration with a laser power of 16 kW (cw) at feed rates of 30 m/min and above were investigated. A comparably large laser beam diameter of 630 μm enabled welding at more than 50 m/min without humping. Full penetration and partial penetration welds were accomplished with depths of 2.4 and 2.0 mm, respectively, without pore formation. The partially penetrated welds show negligible local depth fluctuations in the range of only a few μm. Full penetration welds were performed at edge distances of 4, 5, and 6 mm without occurrence of centerline cracks. This constitutes a significant reduction of the critical zone for the formation of centerline cracks at the close edge position compared to conventional laser beam welding parameters.