TWI

Friction stir spot welding (FSSW) was employed to fabricate dissimilar lap joints between a 6000 series aluminium alloy (Al, 1%Si, 0.5%Mg) in the T4 condition and SPCC mild steel (0.05%C, 0.01%Si, 0.14%Mn) without formation of intermetallic compounds at the weld interface, and the microstructure and mechanical properties of the joints were investigated. FSSW experiments were conducted at rotation speeds of 1000-2000 rpm and residual Al alloy sheet thickness of 0.21-0.36 mm. Joint microstructure was observed by optical microscopy, SEM and TEM, and composition analysis was performed by electron probe microanalysis and energy dispersive spectroscopy. Mechanical properties were characterised by tensile shear tests. The relationship between joint strength, process parameters and stir zone area is discussed.

7th International Symposium, 20-22 May 2008, 2A: Spot 1 (Al-Steel), Paper 02