TWI

Forces experienced by the pin and the workpiece during friction stir welding were measured and used to design a friction stir welding machine which would accept a curved workpiece fed through the machine by hand. Forces in three perpendicular directions were measured whilst friction stir welding aluminium alloy sheet. The flat backing plate beneath the workpiece in a conventional friction stir welding system was replaced by a vertically-mounted wheel with a width of 12.7 mm, driven by a DC motor. The friction stir welding tool is mounted vertically above the wheel, and the parts to be joining were fed (unclamped) between the two. A series of trials was undertaken to optimise the machine settings: the gap between workpieces; feed rate; horizontal position of tool relative to the wheel centre; tool angle to the vertical. Welds prepared in aluminium alloy 6061-T6 plate of 16 mm thickness were assessed visually and by measurements of the ultimate tensile strength.

4th International Symposium, 14-16 May 2003, Session 11: Process & Equipment 4, Paper 01