Abstract
A carbon steel pipe containing primarily ammonia at 750-850°F developed a nitrided case 15-20 mils (0.4-0.5mm) deep. This did not affect the performance of the pipe during operation, however, repair welding was not possible because of cracking. A laboratory procedure was developed wherein nitrided pipe could be successfully welded. The technique consisted of stress relieving the pipe before welding. No post weld stress relief was necessary to effect a sound weld.
Subject
Materials,
Piping,
Welding,
Walls,
Crack propagation,
Ammonia,
Carbon steel pipes,
Stress cracking,
Stress,
Nitrogen,
Nitriding,
Cracks,
Residual stress
© 1994 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).
1994
Association for Materials Protection and Performance (AMPP)
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