Corrosion Failure of an In-service Economizer Tube

Abstract

This investigation was primarily aimed to examine the in-service failure of an economizer tube. Apart from preliminary visual examination, the analysis for the probable cause of failure was supplemented with radiographic examination, metallographic examination, energy dispersive spectroscopy, and scanning electron microscopy. Finally, it was concluded that there was seepage of water from an unusual blowhole-like through-thickness hole in the weld region of the economizer tube. This water vaporized and reacted with the flue gases and caused localized corrosion and led to the ultimate failure of the tube.