Simulated dynamic high pressure sour gas transmission pipe tests were conducted using 20" (508 mm) diameter API grade X42 to X65 linepipes with various Hydrogen Induced Cracking (HIC) susceptibilities. The purpose of the tests was to assess the actual severity of sour gas pipeline environments and to establish a rational test method for evaluation of HIC resistance of linepipe steels. Hydrogen permeation rate was monitored by means of newly developed electrochemical cells during the tests, and HIC crack area ratio of the test pipes was measured by ultrasonic testing (UST) after the long-run tests. The results showed that hydrogen permeation behavior in the simulated tests is roughly classified into two types; one has a higher peak value and rapid decay, and the other has a lower peak value and slow decay. Under the flow rate of 10 ft/s (3.05 m/s), the former was observed at the high H2S partial pressure of 15 atm (1.5 MPa) and the latter at the low H2S partial pressure of 2 atm (0.2 MPa). From the UST, it was clarified that pipes which showed a crack area ratio of 20% or lower in the NACE, TM-01-77 solution exposure test exhibited no HIC in any simulated test.

Subject
Hydrogen induced cracking, Hydrogen permeation, Piping, Corrosion rate, Sour gas, Corrosion reactions, Permeation current, Partial pressures, Permeation, Steel, Brines, Hydrophobic interaction chromatography, Hydrogen
© 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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