An Investigation of the Failure of the Hydrogenated Copper Pipes in the Water Supply Systems

Abstract

The failure of the water copper pipes was investigated on the specimens hydrogenated under different hydrogenation conditions. The strength and ductility of the copper pipe specimens were significantly reduced by hydrogenation. The effect of hydrogenation on the strength and ductility of copper pipes was monitored by applying different hydrogenation conditions such as current density and hydrogenation time. The severity of strength and ductility degradation depends on the hydrogenation condition applied to the copper pipes. Thus, the strength and ductility of the copper pipes were decreased with increasing the current density and hydrogenation time applied to them. Moreover, the copper pipes were hydrogenated at a fixed current density and for different times in the first series of experiments. While in the second series of experiments, the copper pipes were hydrogenated at a fixed time and various current densities. The results showed that the copper pipes hydrogenated for longer time at a fixed current density exhibited more severe decrease in the strength and ductility than those hydrogenated at different current densities for a fixed hydrogenation time. The fracture surfaces of the hydrogenated copper pipe specimens consisted of mixed fracture mode, brittle fracture was found in the outer periphery of the cross sectional areas while ductile fracture was observed in the center of the fracture surfaces of the hydrogenated material. Moreover, the brittle fracture area is increased with increasing the current density applied to the copper pipes. The service life of copper pipes in the water supply systems is reduced significantly by absorbed hydrogen.

Keywords: Copper pipes, Hydrogenation, Strength and ductility.