This paper describes the results of a laboratory study under the direction of a petroleum industry committee involving the use of several standard and non-standard methods for the evaluation of steels for cracking in wet H2S environments. This investigation includes samples of two commonly used pressure vessel steel (ASTM A 516-70 and A 285C) and several test methods including: (1) NACE TM0177 - 90A tensile test, (2) NACE TM0177 - 90A tensile test with one-side (OS) exposure, (3) NACE TM0284, (4) NACE TM0284 with TM0177 solution, (5) TM0284 with OS exposure and (6) Non standard Double Beam (DB) specimen in 4 point bending with both immersion (IMM) and OS exposure. The test results indicated that all test methods showed an higher susceptibility to HIC in the A 516-70 steel used in this study than in the A285 C samples. However, at high applied stress levels both materials exhibited high susceptibility to SOHIC as determined by high values of crack thickness ratio (CTR) in the tensile specimens. OS exposure conditions typically of that found in refinery vessels was significantly less severe from the standpoint of the extent of internal hydrogen cracking produced in both steels. Using DB specimens, the effects of orientation were determined. Specifically, the orientations among the rolling, welding and stressing direction were systematically evaluated. It was found that the condition where the welding direction was parallel (WD - L) to the rolling direction and the stress direction was perpendicular (SD - T) to the rolling direction produced the highest apparent susceptibility to SOHIC (highest CTR values) when the crack measurements were made on the LT plane.

Subject
Hydrogen induced cracking, Test methods, Materials, Welding, Refineries, Rolling, Stress cracking, Base metals, Tensile stress, Steel, Stress oriented hydrogen induced cracking, Hydrophobic interaction chromatography, Sulfide stress cracking
Keywords:
refinery equipment, hydrogen sulfide, hydrogen induced cracking (HIC), stress oriented hydrogen induced cracking (SOHIC), sulfide stress cracking (SSC), test methods, pressure vessels
© 1994 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).
1994
Association for Materials Protection and Performance (AMPP)
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