Alloy 803 was developed for applications in the chemical process industries such as ethylene pyrolysis that require enhanced resistance to oxidation and carburization. In addition to carburization resistance, ethylene pyrolysis furnace tube alloys must also possess adequate stress rupture strength. In environments containing mixed oxidants (oxygen and sulfur), and a high carbon activity such as coal combustion systems, it is known that accelerated oxidation/sulfidation is generally preceded by carburization. An alloy that has a superior oxidation and carburization resistance, would be expected to perform better in environments containing mixed oxidants. This paper will present corrosion performance data for the newly developed alloy in a mixed oxidant environment as well as oxidation and carburization environments. In the case of carburization tests, experiments were conducted to study the effect of carburization on the stress rupture strength of alloy 803 by exposing the stress rupture test specimens in H2-5.5 %CH4-4.5%CO2 for 300 hours at 982°C (1800°F) and then stress rupture testing at 982°C/20.7 MPa (1800°F/3ksi). The results of these tests and other mechanical properties will be presented and compared with alloy HPM, an alloy that is also used for ethylene pyrolysis tubing. Suitable filler metals and welding electrodes to join alloy 803 will also be covered.

Subject
Carburization, Materials, Corrosion resistant alloys, Filler metals, Nickel based alloys, Chromium, Welding, Stress, Furnaces, Aluminum alloys, Titanium alloys, Alloys, Oxidation
Keywords:
alloy 803, alloy HPM, cyclic oxidation, carburization, sulfidation, stress rupture strength, weldability
© 1995 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).
1995
Association for Materials Protection and Performance (AMPP)
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