The resistance of various mechanical splice closures to stress corrosion cracking (SCC) and pitting corrosion in the manhole environment and aerial atmosphere of Taiwan was studied and evaluated in the laboratory and field. A constant-load SCC test with cathodic charging and pitting induction time measurement at open circuit potential were carried out to simulate the complex field condition. In addition, different mechanical closures were exposed at two exposure sites and also installed in a working underground test plant. A follow-up examination was made within two years.

Through the laboratory test and field observation, it was found that the 304 stainless steel closure covering bolt was the only part suffering slight stress corrosion cracking; and hydrogen assisted stress cracking did not occur.

The pitting induction time(ti)for 304 stainless steel under open circuit condition in air-saturated chloride solution follows the following relationships: log ti = c - 0.59log[Cl−] at 20°c - 80°c and log ti - K1 + 1.76/T at 40°c - 80°c.

These results illustrate that increasing temperature and chloride concentration can effectively increase the susceptibility of 304 stainless steel to pit initiation by shortening the pit initiation time.

Subject
Pits, Steel surfaces, Marine environments, Water, Chloride solutions, Cables, Pitting, Immersion, Stainless steel, Chlorides, Stress corrosion cracking, Hydrogen, Chloride stress corrosion cracking
© 1989 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).
1989
Association for Materials Protection and Performance (AMPP)
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