Galvanic corrosion behavior in oil and gas environments when the metal specimens were mechanically scratched was investigated in electrochemical method by using material combinations from carbon steels to duplex stainless steels. Galvanic current and coupled potential soared by mechanical scratching and immediately started to decrease and finally returned to the value before scratching in both sweet and sour environments. Therefore, an increase in galvanic corrosion rate by scratching is negligible small for the long term and localized corrosion due to mechanical scratching does not occurrs. The change in coupled potential immediately after scratching was small in sweet environments and large in sour environments. It is considered that in case of rapid forming corrosion film of less noble metal, galvanic current after scratching decreased rapidly, however, in case of slow forming corrosion film of less noble side, galvanic current after scratching decreased gradually.

Subject
Noble potential, Films, Materials, Sour environments, Density, Current densities, Film formation, Steel, Galvanic current, Galvanic corrosion, Corrosion potential, Electrode potential, Low alloy steel
Keywords:
galvanic corrosion, oil country tubular goods, carbon steel, stainless steel, mechanical scratch, wireline, sour environments, sweet environments
© 1997 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).
1997
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.