Samples of carbon steel tubes were removed from the radiant section of a fired heater after 40 years operation at 950°F to 1000°F (510°C to 538°C) tube metal temperature. The tubes exhibited significant microstructural degradation in the form of advanced pearlite decomposition and graphitization (graphite nodules). However, no evidence of linking of graphite nodules was observed. This paper highlights the results of an API 579 Fitness for Service analysis using the MPC Omega creep methodology to help show that the tubes have significant remaining creep strength and are suitable for continued service, contrary to the results of an API 530 analysis1,2.

Subject
Materials, Corrosion rate, Heaters, Microstructure, Tubes, Walls, Nodules, Graphite, Mechanical failure, Creep, Carbon steel, Graphitization, Oxidation
Keywords:
creep, fired heater assessment, refinery, MPC Omega, graphitized carbon steel, graphitization, graphite nodule, API RP530, API RP579, WRC Bulletin 489
© 2005 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).
2005
Association for Materials Protection and Performance (AMPP)
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