CORROSION BEHAVIOR OF WELDED JOINT OF COPPER PIPE IN SEAWATER

The copper seawater pipe system often leaks at welded joints due to pitting damage and corrosion resulting from the heterogeneity of structure and composition.Experiment results showed that the metallographic structure of the welded joint formed by using brass welding rod was α+β phase.The brass welded joint with α+β phase was subject to corrosion in seawater as a result of dezincification.On the other hand,the cupronickel welded joint formed by using cupronickel rod had better corrosion resistance in seawater due to the microstructure of Cu-Ni-Zn ternary alloy solid solution with single-phase structure of α.