Duplex stainless steel has become the preferred material of construction for new kraft digesters, both for reasons of excellent corrosion resistance and cost effectiveness compared with other materials of construction. Most duplex stainless steel digesters have been constructed using UNS S32205 (type 2205) stainless steel due to the greater availability of this material compared with other duplex stainless steel alloys. UNS S32304 (type 2304) duplex stainless steel has slightly superior corrosion resistance and is also a candidate material of construction for new kraft digesters. This paper describes experiences with duplex stainless steel digesters including replacement of a continuous digester top, replacement of an impregnation vessel, shop construction of batch digesters, and field replacement of a batch digester cylindrical shell.

Subject
Digesters, Test methods, Materials, Liquor, Quality assurance, Welding, Corrosion testing, Construction, Carbon steel, Duplex stainless steel, Stainless steel, Cracking, Cracks
Keywords:
alkaline pulping liquors, corrosion testing, digesters, quality assurance, welding, white liquor
© 2004 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).
2004
Association for Materials Protection and Performance (AMPP)
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