Methods for quantitatively measuring the level of accumulated waterside deposits in cut boiler tube samples are reviewed. For moderate deposit loading, mechanical procedures-either scraping/crimping or short-duration glass-bead blasting-produce consistent and reliable deposit weight density (DWD) measurement (mg/cm2or g/ft2). Glass-bead blasting is preferred for measuring thin and tenacious scales because it completely removes deposits in a short time frame with very limited metal loss. Although the conventional solvent (inhibited acid) technique is useful in removing scales in test areas that are resistant to scraping or blasting, it typically produces high DWD-loading estimates because it corrodes the surface metal. As the deposit mass on the test surface increased (above 20 mg/cm2), the data produced by these three measurement methods showed greater similarity. Also, differences produced by irregular deposit distribution on heavily scaled samples were perceived to be greater than the specific variances of the three techniques.

Subject
Abrasive blasting, Acids, Test methods, Coating removal, Glass, Metal surfaces, Tubes, Beads, Solvents, Scraping, Scale, Boilers, Deposit corrosion
© 1988 Betz Laboratories Inc. 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 prior written permission. 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
Betz Laboratories Inc
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