A full ethylene pyrolysis furnace coil was removed after 20 months of service and analyzed. Magnetic and metallurgical analyses determined that the carburization distribution along the coil was very nonuniform, with severe carburization more prevalent near burners. Hot spots at these locations caused the localized areas of severe carburization. A more uniform temperature distribution within the firebox should reduce localized carburization and extend tube life.

In addition, chemical analyses determined the extent of carbon increase in the carburized case, and electron microprobe studies determined the chemical contents of several phases which precipitated as a result of the extended high temperature service.

Subject
Coils, Carburization, Carbides, Correlation, Microstructure, Tubes, Chromium, Microprobes, Walls, Furnaces, Carbon, Samples, High temperature
© 1983 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).
1983
Association for Materials Protection and Performance (AMPP)
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