The intergranular stress corrosion cracking (IGSCC) susceptibility of the weld heat affect zone (HAZ) of 304L and 316L SS was evaluated in 288°C high purity water at ~+200mVSHE, representative of the boiling water nuclear reactor core environment. Slow strain rate tensile testing results show that both 0.031 wt.%C and 0.008 wt.%C 304L SS materials exhibit IG fracture morphology in the weld HAZ when aged between 450 and 550°C for times up to 2000 hours, while a 316L material exhibits only a trace of transgranular failure. The IG cracking is dependent on the corrosion potential and is sensitive to the surface condition. Double loop electrochemical potentiokinetic reactivation (DL-EPR) measurements indicate that the 304L SS specimens are slightly sensitized and metallographic examination reveals grain boundary precipitates. FEGSTEM and Auger electron analysis are in progress to determine if the weld HAZs are Cr depleted or possess grain boundary impurity segregants. Additional experiments are designed to separate the effects of thermal aging and cold work which may be enhancing the IGSCC susceptibility by promoting Cr depletion and/or impurity segregation.

Subject
Water, Materials, Intergranular stress corrosion cracking, Precipitates, Corrosion cracking, Metallography, Stress cracking, Mechanical failure, Impurities, Cracking, Fracture, Grain boundary, Corrosion potential
Keywords:
IGSCC, 304L, 316L, corrosion potential, cold work
© 1997 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).
1997
Association for Materials Protection and Performance (AMPP)
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