The sulfide stress corrosion cracking (SSCC) resistance of the quenched and tempered AISI 4137-H steel either bare or with a high or low nickel content coatings was studied for geothermal applications. The compari- sion was also performed with high alloyed stainless steels having a high or low nickel content, (26Cr-32Ni-4Mo and 22Cr-5.5Ni-3Mo) utilized for oil applications. The study was carried out using both smooth and precracked specimens in NACE environment and in environments simulating the geothermal fluids found in the area of Larderello (Italy). Some tests were carried out on the geothermal well Casaglia 2 (Ferrara, Italy). The commercial high nickel content coating seems to clearly improve the SSCC resistance of the AISI 4137-H steel. The nickel sulfides as corrosion products are among the factors possibly responsible for SSCC resistance. Altogether, the corrosion behaviour of the nickel-plated AISI 4137-H steel in geotermal applications seems to be comparable with, and even better than, the more expensive 22Cr- 5.5Ni-3Mo duplex stainless steel.

Subject
Acids, Nickel coatings, Zinc nickel coatings, Zinc rich coatings, Geothermal energy, Nickel content, Chemical composition, Corrosion products, Stress, Fluids, Steel, Sulfides, Nickel
© 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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