Although they do occur, dramatic failures of boiler and superheater tubes are somewhat rare. More often the failure modes are subtle. Often a fine line must be drawn between “failure” and normal deterioration with normal life expectancy.

This paper’s primary focus is an integrated approach to elucidation of the mechanisms and causes of boiler and superheater failures used by the author. Examples documented by photos and micrographs are offered. The scope is limited to the waterside of fired boilers, ranging from high pressure utility units through intermediate pressure co-generation, to low pressure process and heating boilers.

Both subtle and classic failures are represented. Techniques include visual observation, metallography, and scanning electron microscopy. Failure mechanisms cited include: stress corrosion cracking, caustic gouging, fatigue, high temperature oxidation, decarburization, and oxygen attack. Subsequent causes include: water treatment practices, manufacturing defects, construction storage and pre-startup, and operation.

Subject
Scanning electron microscopy, Corrosion failures, Tubes, Fracture surfaces, Transgranular stress corrosion cracking, Metallography, Surfaces, Failure analysis, Waterwalls, Boilers, Pitting, Oxygen, Visual assessment
© 1988 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1988
Association for Materials Protection and Performance (AMPP)
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