The need for a nondestructive test for evaluating levels of sensitization in Alloy 800H led to the modification of the electrochemical potentiokinetic reactivation test technique previously developed for AISI 304 stainless steel. The test technique utilized and the results of testing on Alloy 800H specimens aged at temperatures between 450°C and 700°C for zero to 5000 hours are presented. Results indicated that sensitized materials exhibit a peak in measured current density at approximately -30 mV vs. a saturated calomel electrode (SCE) in addition to a general surface activation peak at approximately -150 mV vs. SCE. Unsensitized material exhibited only the general surface activation peak. A current density at a potential of -30 mV vs. SCE of greater than ∼1.6 x 104 micro-amps per centimeter squared of grain boundary area corresponded to complete grain encirclement and grain boundary ditching. Using this criterion and the aging conditions investigated, a time-temperature-sensitization profile was generated for Alloy 800H.

Subject
Test methods, Materials, Stainless alloys, Metal surfaces, Passive films, Current densities, Sensitization, Passivation, Stainless steel, Grain boundary, Alloys, Electrochemical potential, Electrolytes
Keywords:
sensitization, electrochemical, reactivation, Alloy 800H
© 1994 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).
1994
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.