In completion of a series of NACE papers about hydrogen permeation in supermartensitic stainless steels, the present contribution highlights hydrogen uptake and diffusion in respective TIG weld microstructures. Three different weld zones, namely the weld metal center-line, the fusion line region and the heat affected zone have been studied and compared to the base material. Similar to previous studies, such investigations have been carried out with a high and a medium alloyed steel, both have been welded with same type of matching high alloyed supermartensitic filler wire. It turned out that the diffusion coefficient of the HAZ and the weld metal as compared to that of the base material is significantly dependent on the filler wire composition and on the amount of retained austenite. This also means that the joint regions of tubular supermartensitic stainless steel components, as for instance subsea flowlines, have more carefully to be considered with respect to a different hydrogen transport in the weld zones and their cracking resistance, respectively.

Subject
Materials, Microstructure, Diffusion, Supermartensitic stainless steel, Welding, Wiring, Inspection, Permeation, Steel, Weld metal, Austenite, Heat affected zone, Hydrogen
Keywords:
hydrogen permeation, supermartensitic stainless steel, weld microstructure, diffusion coefficient, subsurface concentration, free corrosion, chemical composition
© 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)
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