Three failure analyses involving iron-nickel-chromium alloys (Alloy 800H and niobium modified HP-40) in high temperature steam service 1300°F to 1450°F (704°C to 788°C) are presented. Boiler water carryover conditions led to steam-side salt deposits containing sodium, chlorine, and sulfur species. The unique conditions of extremely high temperatures and localized accumulation of aggressive salt species resulted in component failures that involved a molten salt attack mechanism not typically observed in steam-side environments.

Subject
Materials, Salts, Metal surfaces, Tubes, Chromium, Bellows, Iron, Magnification, Corrosion products, Mechanical failure, Metals, Deposit corrosion, Nickel
Keywords:
Alloy 800H, UNS No. N08810, UNS No. N08811, Incoloy 800H, HP-40, HP-40Nb, niobium modified HP-40, molten salt attack, mixed molten salt attack, steam-side failures
© 1996 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).
1996
Association for Materials Protection and Performance (AMPP)
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