Experience has shown that stainless steels can suffer from Hydrogen Induced Stress Cracking (HISC) under cathodic protection in seawater. During the last years major research projects have been executed to establish a better understanding of the mechanisms and to develop qualification methods and design procedures. It is a common understanding that the probability of HISC initiation increase with decreased temperature. Most of the testing has therefore been executed at room temperature or at lower temperatures. What about higher temperatures – will HISC still be a problem at temperatures above 80°C?

This paper presents results from a test program examining the HISC susceptibility of 25% Cr super duplex stainless steel (UNS S32750) at temperatures up to 150°C. Both Slow Strain Rate Testing (SSRT) and Single Edge Notch Test (SENT) specimens were tested in 3.5% NaCl solution. The SSRT results from hydrogen charged specimens were compared to specimens tested in air (no hydrogen charging).

The results from the testing indicated that 25% Cr super duplex stainless steel was susceptible to HISC even at 150°C.

Subject
Scanning electron microscopy, Cathodic polarization, Constant load, Test methods, Materials, Yield stress, Stress cracking, Stress, Elongation, Duplex stainless steel, Fracture, Austenite, Hydrogen
Keywords:
Hydrogen Induced Stress Cracking, seawater, cathodic protection, elevated temperature, duplex stainless steel
© 2011 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).
2011
Association for Materials Protection and Performance (AMPP)
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