A section from an alloy 800 reformer tube, which served satisfactorily in a steam-methane reformer for more than 19 years, was removed for examination after the permanent shut-down of the operation. The operating conditions for this section of tube had been about 140 psig at 1450°F (788°C).

The maximum penetration of intergranular oxidation from the outside surface was 0.006 in. (0.15 mm) while the total depth of attack due to oxidation and carburization from the inside surface was 0.025 in. (0.64 mm).

The most abundant secondary phase present was σ. The σ phase had not affected the 1400°F (760°C) tensile properties but had reduced the room-temperature tensile and stress-rupture properties.

Subject
Sigma phase, Carburization, Materials, Metal surfaces, Tubes, Walls, Magnification, Tensile properties, Tubing, Oxide surfaces, Alloys, Weld metal, Oxidation
© 1986 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).
1986
Association for Materials Protection and Performance (AMPP)
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