Supermartensitic stainless steels have been widely used for line pipe application because of their high strength and excellent corrosion resistance in corrosive conditions. However, field failures due to stress corrosion cracking (SCC) near the fusion line of girth weld joints were found in early applications. Post weld heat treatment (PWHT) was effective to eliminate sensitivity of SCC. In this paper, the effect of PWHT temperature on SCC behavior of low C-13 %Cr steels weld joints in hot acid environments is examined. Low C-13 %Cr-2%Mo supermartensitic stainless steel was welded by GMAW using superduplex stainless steel wire. PWHT temperature was changed from 550 degree C to 850 degree C. Lower PWHT temperature leads to cracking near fusion line of girth weld joints. Higher PWHT temperature leads to environmental cracking in weld metal due to sigma phase precipitate. Adequate PWHT temperature range seems to be from 600 degree C to 700 degree C.

Subject
Acids, Sigma phase, Environmental cracking, Supermartensitic stainless steel, Welding, Wiring, Joints, Welded joints, Cracking, Cracks, Stress corrosion cracking, Test specimen, Martensite
Keywords:
Supermartensitic stainless steel, Superduplex GMAW wire, Welded joints, PWHT, SCC
© 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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