Fracture Analysis of Stress Corrosion Cracking in Heat Exchanger Tubes

Abstract

The serious leakage in the tube bundles of a heat exchanger was found in a plant. By using the Macro and Micro morphology of cracks, chemical composition analysis, metallographic inspection and corrosion products energy dispersive spectroscopy (EDS) analysis, the leakage failure cause of the tube bundles was analyzed. It has been proved that the branch-shape cracks are generated from the outer wall of the tube bundles. Both ends of the crack were even and there was no significant plastic deformation. The crack propagation zone was covered with thick corrosion products. The results of EDS show high levels of oxygen and sulfur in the region, which showed that sulfide stress corrosion is the main cause of tube cracking.