Type 420 stainless steel (13 Cr) production tubing is being used successfully in deep sour gas wells in the Tuscaloosa Trend. Despite their reputation for poor H2S cracking resistance in laboratory tests, 12-13% Cr steels continue to perform well in sour environments. NACE Tensile Test and Shell bent beam test results indicate Type 420 is more resistant to H2S cracking than Type 410, but is not as resistant as carbon steel, at the 586-690 MPa (85-100 ksi) yield strength level. In addition to evaluating Type 420 stainless steel in the standard NACE Tensile and Shell bent beam tests, the effects on cracking tendency of chloride concentration, pH, and H2S gas concentration in the NACE Test solution were also examined. Cracking tendency of Type 420 increases as the NaCl concentration in the NACE Tensile Test is increased from 0% to 5%. Above 5% NaCl, cracking susceptibility remains constant. Cracking susceptibility is reduced when the initial pH of the NACE solution is adjusted to 4.0. Cracking tendency is also reduced when the H2S concentration in the gas used for the NACE test is reduced below the standard 100%. Type 420 appears to be more resistant to H2S cracking than is indicated by standard laboratory tests, at least in low H2S level sour environments.

Subject
Materials, Manufacturing, Yield stress, Hydrogen concentration, Tubes, Sodium chloride, Tensile tests, Cracking resistance, Sodium chloride solution, Tubing, Stainless steel, Cracking, Yield strength
© 1984 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).
1984
Association for Materials Protection and Performance (AMPP)
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