Two weldable martensitic SS grades (1.5Mo and 2.5Mo) have been welded using matching consumables. Both seam welds and girth welds have been undertaken testing with respect to sensitivity towards sulphide stress cracking (SSC). The effect of chloride concentration, either simulating condensed water situation or simulated formation water situation, and H2S partial pressure has been investigated. Based on these studies application limits are evaluated. Under condensed water conditions the critical partial pressure of H2S increased 1-2 decades when the NaCl concentration was reduced from 1000 to 100 ppm. At 100 ppm of NaCl the critical partial pressure of H2S was > 0.01 MPa independent of weld (seam or girth) and post treatment (grit blasting and pickling) of weld. At 1000 ppm of NaCl the critical partial pressure varied dependent on the surface conditions. The same situation was observed when testing in formation water conditions. The data also show a large increase in the SSC resistance when the seam welds were grit blasted prior to pickling and passivation.

Subject
Test methods, Seams, Water, Materials, Pickling, Girth welds, Sodium chloride, Partial pressures, Condensed water, Cracking, Sulfide stress cracking, Alloys, Chlorides
Keywords:
SSC, welding, martensitic stainless steels, application limits
© 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)
You do not currently have access to this content.