Friction Skew-stir welding of lap joints in 5083-0 aluminium

A variant of the friction stir welding technique developed at TWI, called Skew-stir (tradename) was applied to the welding of lap joints in Al alloy AA5083 - 0. This technique differs from the conventional method in that the axis of the tool is given a slight inclination, or skew, to that of the machine spindle. It is particularly advantageous in instances where a wide weld region is required, such as lap joints in which the interface is perpendicular to the machine axis. The microstructures and mechanical properties of welds made using both a conventional pin type probe and the rotary Skew-stir technique with an A-Skew ( tradename) probe were studied. The joints made using the Skew-stir technique sustained significantly higher tensile loads and had longer fatigue lives compared with those made using the conventional pin type probe.