TWI

An abrasion circle friction stir spot welding (ABC-FSSW) technique was employed to fabricate dissimilar metal joints between aluminium and steel automotive sheets, and the microstructure, mechanical properties and weld formation mechanisms of the joints were investigated. The materials studied were AA 6111-T4 (Al, 0.75%Mg, 0.69%Si, 0.75%Cu) and DC04 low carbon steel (0.08%C, 0.4%Mn). Lap welding experiments were performed by ABC-FSSW with a scroll-profile steel shoulder tool and a tapered WC probe at a shoulder plunge depth of 0.1 mm and translation speeds of 60-2000 mm/min. Welded joint microstructure was observed by TEM equipped with energy-dispersive X-ray spectroscopy. Mechanical properties were characterised by hardness profile measurement and lap-shear testing to determine the failure load and fracture energy.

9th International Symposium, 15-17 May 2012, Session 9B: FSSW, Paper 01