Structural integrity of copper-nickel to steel using metal inert gas welding

Abstract

Metal inert gas (MIG) welding may be used as a technique to attach copper-nickel panels to steel substrates to minimize the corrosion and biofouling of offshore structures and ship hulls. A series of plug welds must be located on each panel in order to eliminate bowing when the panels are subjected to compressive loadings. Laboratory tests on MIG plug-welded specimens have shown that the fatigue life of the plug welds is the same as the fatigue life of the copper-nickel cladding without the plug welds. The possible increase in fatigue life attributed to the lack of bowing of the sheets is offset by the stress concentration created by the weld. SEM examination of the failed weld site showed that fracture was predominantly intergranular in the regions adjacent to the weld, while regions remote from the weld exhibited fatigue striations.