Reactor vessels for high temperature, high pressure hydrogen services such as hydrocracking, hydrodesulfurizing, and coal conversion, have internal attachments as shown in Fig. 1. Cr-Mo steel base metal is covered by stainless steel suitable for the environment in the reactor. For hydrocracking and hydrodesulfurizing, Type 347 stainless steel is favored due to its better resistance to polythionic acid corrosion1 . In order to maintain an effective thickness of the stainless steel, an approximately 5/16 inch thick double layer weld overlay is applied. A first layer of Type 309 alloy is usually applied followed by a second layer of Type 347 material. Internal rings and pedestals which support trays, beams, and baskets are attached by welding to the overlaid surface. Type 321 stainless steel internals welded by Type 347 filler metal are commonly used in hydrocracking and hydrodesulfurizing reactors.

Subject
Materials, Hydrogen content, Reactors, Ferrite content, Stress cracking, Base metals, Stainless steel, Fatigue, Ferrite, Cracks, Weld metal, Ductility, Hydrogen
© 1977 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).
1977
Association for Materials Protection and Performance (AMPP)
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