This paper describes a research program conducted to determine susceptibility of steels used in low-pressure (LP) turbine rotors of power plants to stress corrosion cracking (SCC) in LP turbine environments. Slow-strain-rate tests were conducted on samples from two 3.5 NiCrMoV forgings over a temperature range of 93 to 157°C (200 to 315°F) in three potential LP turbine environments--water, NaCl solutions, and dilute caustic-chloride solutions. The effect of oxygen also was investigated. A limited number of constant-load tests were conducted in 10% NaOH solutions and in a dilute caustic-chloride solution. Results indicate cracking occurs under specific conditions of temperature and electrode potential. Transgranular cracking occurred in chloride solutions and in oxygenated water. Cracking in dilute caustic-chloride solutions was both transgranular and intergranular. Results of constant-load tests were found to depend upon procedures followed in establishing test conditions.

Subject
Strain rate, Water, Turbines, Sodium chloride, Stress cracking, Intergranular cracking, Crack depth, Sodium chloride solution, Steel, Oxygen, Cracking, Stress corrosion cracking, Electrode potential
© 1984 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).
1984
Association for Materials Protection and Performance (AMPP)
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