The wrought, nickel-molybdenum (Ni-Mo) and nickel-chromium-molybdenum (Ni-Cr-Mo) alloys are very important materials of construction in the chemical process, pharmaceutical, petrochemical, and oil and gas industries. The objective of this study is to compare the resistance of “as welded” and PWHT samples of several alloys to chloride-induced stress corrosion cracking (SCC), pitting, and crevice corrosion, using standard ASTM test procedures. Commercial alloys HASTELLOY® B-3® (UNS N10675)*, C-22® (UNS N06022)*, C-276 (UNS N10276)*, C-2000 ® (UNS N06200) *, G-35® (UNS N06035)* and HYBRID-BC1® (UNS N10362)* were selected in this study. The gas tungsten arc (GTAW/TIG) welding process was used in sample preparation. The primary conclusion from this study is that no benefit appears to accrue from PWHT regarding resistance to SCC and pitting corrosion. However, there are some distinct advantages of PWHT with regard to crevice attack for UNS N06200, UNS N06035 and UNS N10362 alloys.

Subject
Weld attack, Corrosion resistant alloys, Corrosion rate, Nickel based alloys, Nickel chromium molybdenum alloys, Acid attack, Crevices, Corrosion attacks, Pitting, Corrosion resistance, Alloys, Stress corrosion cracking, Chloride stress corrosion cracking
Keywords:
stress corrosion cracking, pitting and crevice corrosion, corrosion resistant alloys, hydrochloric acid, sulfuric acid, sensitization
© 2021 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).
2021
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.