NACE Standard MR0175-2003 permits the use of all copper alloys without any restrictions, but cautions that “Copper-based alloys may undergo accelerated mass-loss corrosion in sour oilfield environments, particularly if oxygen is present”. In order to better understand the environmental limitations of four copper-based alloys laboratory immersion tests were performed in a highly corrosive sour environment and stress cracking tests were performed in accordance with NACE TM0177.

Aluminum-bronze alloy (UNS C63000), aluminum-bronze alloy (UNS C62730), beryllium-copper alloy (UNS C17200), and copper-nickel alloy (UNS C96900) were tested. Additionally, samples of type 17-4PH stainless steel (UNS S17400), type 410 stainless steel (UNS S41000), type 660 stainless steel (UNS S66286), nickel-based alloy 718 (UNS N07718), and nickel-based alloy 625 (UNS N06625) were subjected to the same tests to establish baseline levels of corrosion resistance against which the performance of the four copper-based alloys could be compared. The results presented in this paper demonstrate that the four copper-based alloys were subject to much higher levels of mass-loss corrosion than any of the baseline materials. Duplicate tests confirmed the difference in mass-loss corrosion behavior demonstrated by the individual copper-based alloys. The aluminum-bronze alloys (UNS C63000 and UNS C62730) were shown to be free from sulfide stress cracking in the NACE TM0177 test for the specific material conditions tested.

Subject
Test methods, Materials, Corrosion resistant alloys, Stainless alloys, Corrosion rate, Materials performance, Nickel based alloys, Sour environments, Copper nickel alloys, Corrosion resistance, Stainless steel, Aluminum alloys, Sulfide stress cracking
Keywords:
aluminum-bronze, beryllium-copper, copper alloy, stainless steel, nickel alloy, mass-loss, sulfide stress cracking, H2S environment, UNS C63000, UNS C62730
© 2004 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).
2004
Association for Materials Protection and Performance (AMPP)
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