Several materials were evaluated for use in nuclear steam generators (NSG). These materials were exposed to corrosive conditions representative of those found in nuclear steam generators. The materials evaluated were gold, titanium, tantalum, niobium, Hastelloy C-276, Hastelloy G, Nickel 200, nickel- base Alloy 625, and heat-treated nickel- base Alloy 600. The test environments simulated acid pitting attack, caustic stress corrosion cracking and reduced sulfur attack.

In the pitting environment, the monolithic materials did well, however Nickel 200, nickel-base Alloy 600 and Hastelloy G3 did poorly. The remaining alloys, nickel-base Alloy 625 and Hastelloy C-276 were relatively unaffected in the pitting environment.

Tantalum, titanium, niobium, nickel-base Alloy 625 performed poorly in the environment designed to evaluate resistance to caustic cracking. Nickel- base Alloy 600 (stress-relieved), Hastelloy C-276, Hastelloy G-3 and Nickel 200 compared fair to good in the caustic sodium. The gold was unaffected in the hot caustic solution.

In the environment selected to represent a reduced sulfur environment, nickel-base Alloy 625 and Hastelloy C-276 exhibited considerable resistance. The nickel-base Alloy 600 was attacked within a relatively short period of time.

Subject
Acids, Pits, Sulfur, Materials, Tantalum, Corrosion resistant alloys, Nickel based alloys, Steam generators, Gold, Pitting, Caustic stress corrosion cracking, Titanium alloys, Alloys
© 1986 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).
1986
Association for Materials Protection and Performance (AMPP)
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