TWI

In relation to the implementation of friction stir welding (FSW) for stringer-skin type lap joint fabrication in aeronautical applications, an investigation is presented into the overlap welding of an extruded profile AA 7050-T7651 aluminium alloy stringer to AA 2024-T3 and Al-clad AA 7475-T761 alloy sheet skin materials (thickness 2 mm). FSW tests were conducted using a Kuka KR500-3MT robotic system equipped with a specific FSW spindle and force control operational capability. Different FSW tool designs (threaded probe or threaded+3 flat probe, probe length 2.2 or 2.5 mm) and process parameters (rotational speed 1000 or 800 rpm, travel speed 150 or 250 mm/min) were employed to study their effects on lap joint formation and weldment properties. Cross-sectional microstructure was observed by optical microscopy. Mechanical properties were characterised by Vickers microhardness measurements and static pull-out tests.

12th International Symposium, 26-28 Jun 2018, Session 5B: Joint Interfaces, Paper 02