Failure Analysis of Cu/Ni Tubing used in a Desalination Plant

Wires from a failed conveyer belt exhibited rupture. The conveyer belt is part of an industrial cooking spiral oven. The fractured wires exhibited both corrosion initiated fatigue and stress corrosion cracks. Corrosion fatigue requires a cyclical stress, and SCC involves a static tensile stress. Both corrosion fatigue and SCC propagate perpendicular to the applied stress. The networks of branched cracks documented in the metallographic results of the conveyer belt demonstrated the classic lighting strike appearance for chloride induced stress corrosion cracking.