As the first step for development of the corrosion resistant superheater tube materials of 500°C, 100 ata used in high efficient waste-to-energy plants, field corrosion tests of six conventional alloys were carried out at metal temperatures of 450°C and 550°C for 700 and 3000 hours in four typical Japanese waste incineration plants.

The test results indicate that austenitic alloys containing approximately 80 wt% [Cr+Ni] show excellent corrosion resistance. When the corrosive environment is severe, intergranular corrosion of 40~200 μm depth occurs in stainless steel and high alloyed materials. It is confirmed quantitatively that corrosion behavior is influenced by environmental corrosion factors such as Cl concentration and thickness of deposits on tube surface, metal temperature, and flue gas temperature. The excellent corrosion resistance of high [Cr+Ni+Mo] alloys such as Alloy 625 is explained by the stability of its protective oxide, such that the time dependence of corrosion nearly obeys the parabolic rate law.

A good correlation was observed between the laboratory corrosion test obtained by means of crucible method and field corrosion tests in comparison with coating method.

Subject
Waste incineration, Materials, Corrosion resistant alloys, Tubes, Molybdenum alloys, Corrosion testing, Flue gas, Thickness loss, Metals, Ash, Corrosion resistance, Intergranular corrosion, Wastes
Keywords:
fireside corrosion, municipal waste, incineration, hot corrosion, superheater tube material, high temperature corrosion resistant alloys, chlorine corrosion, field corrosion test
© 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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