A new 15%Cr stainless steel developed for OCTG shows improved general corrosion resistance in CO2-containing well environments as compared with the conventional 13%Cr martensitic stainless steels. This steel can be used in the well at up to 180°C in 10%NaCl solution containing CO2 with small amounts of H2S. General corrosion resistance is able to be estimated by Cr-12C+0.75Ni+10N = GCI (General Corrosion Index). High toughness and good productivity are achieved by reducing the δ-ferrite phase. The lower Ni content is desirable for the cost performance. From these results, we manufacture L-80 grade 15%Cr steel tubulars with 0.11%C, 0.5%Mo, 1.5%Ni and 0.08%N. This steel can replace a part of ferritic/austenitic duplex stainless steels in some gas wells producing CO2 with small amounts of H2S.

Subject
Costs, Immersion tests, Materials, Manufacturing, Corrosion rate, Productivity, Steel, Pitting, Corrosion resistance, Duplex stainless steel, Toughness, Types of corrosion, Martensitic steel
Keywords:
15%Cr stainless steel, oil country tubular goods, general corrosion resistance, pitting corrosion resistance, CO2-containing well environment, 13%Cr martensitic stainless steels, Chromium, Carbon, Nickel, Molybdenum
© 1991 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).
1991
Association for Materials Protection and Performance (AMPP)
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