Alloys exposed in gasifier environments for 3600-5000+ hrs at 500-800°C were examined in the laboratory to determine their suitability for long term use at temperatures above 500°C. The alloys contained 20-45% Ni, 20-27% chromium, with the balance being Fe.

Partially cooled specimens of alloy 800 and SS 310, with metal temperatures in excess of 600°C were heavily carburized internally and suffered from accelerated oxidation and sulfidation. Superheater tubes of the same alloys, with metal temperatures in the 500-550°C range showed incipient carburization and did not develop protective low sulfur, high chromia scales. The only alloy which did develop a low sulfur, high chromia scale contained 3% vanadium, in addition to 27% chromium. This alloy did not carburize.

Subject
Sulfur, Iron nickel chromium alloys, Carburization, Carbides, Metal surfaces, Nickel based alloys, Chromium, Corrosion scales, Oxide scales, Scale formation, Carbon, Sulfides, Alloys
© 1991 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).
1991
Association for Materials Protection and Performance (AMPP)
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