Failure Analysis of Welded Pipe in Water Supplies for Apartment

Abstract

Galvanized Steel pipes have been widely used in industries and apartments. Unexpected early leakage has been found in an apartment. Tunneling corrosion or penetration was found in the water supply pipes. The chemical compositions of the pipes and properties of coating layer were evaluated. The pipes met the specification of KS D 3507. The cause of early failure was analyzed through the examination of macrostructures and microstructures. It was found that the pipes were failed by grooving corrosion, which resulted from galvanic corrosion of weld bead and matrix.