The purpose of this work is to evaluate the stress corrosion cracking (SCC) behaviour of two NiCrMoV alloys of Italian production, that are materials used for low pressure (LP) turbine discs in LWR nuclear plants.

All the tests reported in this investigation have been performed using the slow strain rate technique (SSRT).

A first set of experiments has been conducted in pure deaerated caustic solutions in a static Ni autoclave system, in order to determine the effects of temperature and NaOH concentration on the SCC behaviour of these materials.

In a second set of tests, the influence of the oxygen content on cracking was studied; for this purpose, specimens were strained to fracture at 200°C in pure water with various amounts of oxygen; a refreshed autoclave system was used to permit a continuous monitoring of the chemical parameters.

Both alloys showed a decreasing SCC susceptibility as NaOH concentration and temperature decreased. The alloy with lower Ni content seemed to behave slightly better in caustic solutions and somewhat worse in pure oxygenated water.

Subject
Scanning electron microscopy, Strain rate, Water, Autoclaves, Fracture surfaces, Pure water, Mechanical failure, Elongation, Heat, Steel, Oxygen, Caustic stress corrosion cracking, Stress corrosion cracking
© 1987 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).
1987
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.