The "full ring" test has been recently developed as an intermediate type of test between small coupon tests and full scale testing under internal pressure in order to evaluate a linepipe for sour service conveniently. Factors of this test and their effects on test conditions or results have been Investigated in order to characterize the full ring test.

The electrochemical hydrogen permeation measurement was effective to quantify the effects of environmental factors on test conditions. The hydrogen permeation coefficient (JxL) through a tested pipe was affected by not only pH and H2S content but also the galvanic corrosion and surface conditions.

The metallurgical factors for hydrogen cracking were both nonmetallic inclusions in linepipe steels and welding defects in circumferential weldments. The JxL was also used to estimate a resistance exactly. The threshold value estimated from the full ring test results will show an excellent resistance in the actual environment.

Subject
Pipe surfaces, Materials, Hydrogen permeation, Piping, Linepipe, Weldments, Welding, Internal stress, Stress cracking, Stress, Internal surfaces, Steel, Hydrogen stress cracking
Keywords:
full ring test, linepipe, circumferential welding, stress, hydrogen permeation, hydrogen induced cracking (HIC)
© 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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