Corrosion-fatigue of Type 403 stainless steel turbine blades at The Geysers has affected the availability factor of the units. Blade and shroud failures have necessitated scheduling turbine overhauls more frequently than experienced with conventional fossil fired units. Analysis of broken turbine blades and shrouds from a number of different units and manufacturers1  has indicated that minor variations in tempering temperature within the typical range of 500 to 700°C can create large variations in microstructure in turbine grade Type 403 stainless steel. These microstructural variations are believed to be responsible for the significant fatigue strength variations seen in blading material at The Geysers. This investigation was undertaken in order to determine the effect of geothermal steam on the fatigue strength of AISI Type 403 and 422 stainless steels, and to determine the effect of heat treatment on the fatigue properties of these alloys in geothermal steam.

Subject
Geothermal energy, Corrosion fatigue, Materials, Microstructure, Turbines, Stress, Impurities, Stainless steel, Fatigue, Steam, Hardness, Heat treatment, Fatigue strength
© 1979 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).
1979
Association for Materials Protection and Performance (AMPP)
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