A deaeration process and an ammonia addition are made during shutdown periods for a thermal power plant operated using Oxygenated Water Treatment (OT). This paper describes the effects of such water condition changes on corrosion behaviors of carbon and low alloy steels, particularly from the viewpoint of oxide film characteristics. As hematite films formed by OT tend to dissolve under the All Volatile Treatment (AVT) condition, the corrosion proceeds in a stepwise manner due to the condition changes. Preoxidation in high pH and high dissolved oxygen concentration water (HipH/DO) forms very protective oxide films on the steels and suppresses corrosion in the OT condition.

Subject
Water, Materials, Oxide formation, Oxide films, Hematite, Acidity, Corrosion behavior, Film formation, Magnetite, Carbon steel, Carbon, Corrosion protection, Low alloy steel
Keywords:
Oxygenated Water Treatment, All Volatile Treatment, thermal power plant, carbon steel, low alloy steel, shutdown, corrosion inhibition, oxide films, magnetite, hematite
© 1994 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).
1994
Association for Materials Protection and Performance (AMPP)
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