The crevice corrosion behavior of 22%Cr duplex stainless steel, which has come into wide use for its high strength and SCC resistance, was investigated in the simulated sour gas conditions below 80°C.

The crevice corrosion is accelerated by the following factors; partial pressure of H2S, temperature, decreasing pH of the test solution, and the addition of elemental sulfur. Compared the duplex stainless steel and Type 316 stainless steel, the former was more resistant to the crevice corrosion in H2S-Cl- environment.

A simple model of the crevice corrosion was proposed, in which the generation process and the crevice corrosion mode were discussed. The incubation time of crevice corrosion based on this model was calculated and the effect of the crevice gap, the rate of the metal dissolution, the depassivation pH, and the initial pH of the test solution was clarified. The mode of crevice corrosion was changed with the partial pressure of H2S, which can be explained by the stability of NiS film and the depassivation pH in the crevice.

Subject
Sour environments, Metal dissolution, Partial pressures, Acidity, Constants, Incubation, Crevices, Current densities, Corrosion modeling, Crevice corrosion, Steel, Duplex stainless steel, Corrosion potential
© 1987 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).
1987
Association for Materials Protection and Performance (AMPP)
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