Several candidate materials were evaluated by corrosion testing in autoclaves containing white and black liquors for batch digesters. The relationship between corrosion rate and corrosion potential was determined for ASTM SA516-Grade 70 carbon steel, UNS S30403 (Type 304L) austenitic stainless steel, UNS S31803 (“2205”) and UNS S32550 (“2605”) duplex stainless steels, and two stainless steel weld overlays, applied by the GMAW (gas metal are welding) and SAW (submerged are welding) processes. The tests revealed that SA516-Grade 70 carbon steel and type 304L stainless steel can experience high rates of corrosion. For the duplex stainless steels and weld overlays, corrosion resistance improved with chromium content. A chromium content of at least 25% was found to be necessary for good corrosion resistance.

Subject
Digesters, Materials, Corrosion rate, Liquor, Chromium, Black liquors, Penetration, Carbon steel, Corrosion resistance, Duplex stainless steel, Stainless steel, Corrosion potential, Thermal spray coatings
Keywords:
austenitic stainless steel, black liquor, carbon steel, corrosion testing, duplex stainless steel, pulp and paper, thermal spray, weld overlay, white liquor
© 1997 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).
1997
Association for Materials Protection and Performance (AMPP)
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