This paper reports a study of the effects of impurities on the sensitizaton and intergranular corrosion of Type 304 stainless steel. The impurities considered are sulfur, phosphorus, silicon and nitrogen. It is shown that sulfur has little effect on the intergranular corrosion, except at the high electrochemical potentials of the Huey test and oxalic acid test. At these potentials chromium sulfides precipitated at the grain boundaries and in the matrix are preferentially attacked. Phosphorus has little effect on intergranular corrosion as measured by the modified Strauss test, but it greatly accelerates intergranular corrosion in the Huey test. The magnitude of this effect depends on the extent of chromium depletion. Silicon has little effect on intergranular corrosion. Nitrogen, however, reduces susceptibility to sensitization. Thus, in the nitrogen doped heats longer times are required at any temperature to reach a given level of sensitization.

Subject
Sulfur, Phosphorus, Purity, Corrosion attacks, Impurities, Heat, Steel, Sensitization, Carbon, Stainless steel, Elements, Grain boundary, Alloys
© 1981 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).
1981
Association for Materials Protection and Performance (AMPP)
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