Ductility is also one of the most important factors that
effects the spot weld quality. The ductility of a resistance
weld is determined by the composition of the base metal
and effect of high temperatures and subsequent rapid cooling
on that composition. The nearest thing to ductility
measurement is the hardness test since the hardness of
metal is usually an indication of its ductility [1]. Therefore,
the hardness measurement was performed on the weld nugget,
HAZ and the base metals of weldment as seen in
Fig. 7. The effect of peak current on the hardness across
the weldment was determined and result is shown in Fig. 7.