A number of in-bed tube sections of five different steel alloys that had been exposed in the Point Tupper atmospheric fluidized bed combustor (AFBC) by the Canada Center for Mineral and Energy Technology (CANMET) were metallographically analyzed. The tubes had been exposed at temperatures from 450° to 850°C for time periods from 1000 to 10,000 hours. It was determined that, generally, more metal was lost from the bottom outer surfaces of the tubes than from the tops as the result of two different scale loss mechanisms. The scale loss mechanisms were related to the different impact angles and velocities of the particles which struck the top and bottom surfaces of the tubes. The presence of AFBC bed material on and in the scales modified the scale loss behavior and, in the instance of at least one of the alloys, the 9Cr1Mo steel, appeared to provide some protection.

Subject
Steel surfaces, Materials, Composition, Metal surfaces, Tubes, Oxide layers, Metal loss, Oxide scales, Oxide surfaces, Scale formation, Steel, Scale, Spalling
© 1987 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).
1987
Association for Materials Protection and Performance (AMPP)
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