The Importance of Governing Metal Thickness for Resistance Spot Welding of Aluminium

A study was carried out to investigate the effect of governing metal thickness (GMT) on weld quality and strength of resistance spot welded (RSW) AA5754 aluminium. Quasi-static joint strengths were evaluated for 27 different joint stack-ups in three test geometries: lap-shear, coachpeel and cross-tension; whilst micro examination was conducted on some of the samples to assess weld quality. The results derived from over 1000 samples show the importance of GMT and its various effects: the GMT has a significant effect on welding quality and joint strength by controlling the attainable weld diameter, regardless of stack-ups; depending on loading conditions, its effect may differ.