Journal of Failure Analysis and Prevention

, Volume 11, Issue 4, pp 357–362 | Cite as

Caustic Corrosion Failure of Back Wall Riser Tube in a High-Pressure Boiler

  • M. Mobin
  • A. U. Malik
Case History---Peer-Reviewed


This article describes the results of an investigation concerning the failure of the back wall riser tube of a high pressure boiler in a SWCC dual purpose power/water cogeneration plant. The failure occurred in one tube (facing furnace) which contained eight ruptured openings covering a length of approximately 1.8 m. The tube material was carbon steel (SA 210A1). The cause of the failure was determined by on-site visual inspection of the boiler and detailed macro and micro examinations of inner and outer scales on the tube. The in situ non-destructive testing of selected boiler riser tubes was carried out using boroscope and ultrasonic test (UT). The composition of the tube material and fire and water-side scale deposits were analyzed by energy dispersive x-ray (EDX) and inductively coupled plasma (ICP) techniques. The cause of the failure of the riser boiler tube appears to be caustic attack. The inside brown scale that developed during service resulted in overheating, wall thinning due to caustic corrosion, and the associated ruptures of the tube in areas of high stress. The escaping steam eroded the outer surface of the tube resulting in heavy loss of metal around the rupture points (punch). Recommendations are given to prevent/minimize such failures.


Boiler riser tube Caustic corrosion Over heating High pressure boiler Energy dispersive x-ray 


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Copyright information

© ASM International 2011

Authors and Affiliations

  1. 1.Department of Applied Chemistry, Faculty of Engineering and TechnologyAligarh Muslim UniversityAligarhIndia
  2. 2.Saline Water Desalination Research InstituteSaline Water Conversion Corporation (SWCC)Al-JubailSaudi Arabia

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