Preferential corrosion of carbon steel weld corrosion and its inhibition were studied by corrosion tests in a flow loop. Eight weld metal/parent metal combination were tested at 60 °C, 1 bar CO2, pH 5-6. Results from 3 selected welds are presented. The tests were carried out in high and low conductivity NaCl brines (0.35 and 35 g/L). It was found that corrosion inhibition could prevent preferential weld corrosion when inhibitor was dosed at sufficiently high concentration. A higher concentration was needed to inhibit the corrosion on some of the weld metals than the parent steel. Furthermore, it was found that too low concentrations of inhibitor could initiate galvanic corrosion of the weld and accelerate preferential corrosion.

Subject
Weld attack, Electrochemical impedance spectroscopy, Inhibitor performance, Corrosion rate, Flow velocity, Corrosion loops, Precorrosion, Corrosion inhibitors, Brines, Galvanic current, Cathodic inhibitors, Conductivity, Anodic inhibitors
Keywords:
corrosion, carbon dioxide, carbon steel, welds, inhibition
© 2005 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).
2005
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.