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Abstract
Purpose of this paper is to show the effect of long-term service at elevated temperatures on microstructural changes of cast steel reformer tubes made of the alloy IN-519 (24%Cr, 24%Ni, Nb). The relationship between mechanical properties and microstructure degradation is discussed. Investigations were performed on five tubes taken from ammonia reformer furnace. Tubes worked at temperature of 880C and 3,2 MPa pressure. The operation time varied from 24000 to 95000 hours. Metallographic investigations of IN-519 cast steel catalytic tubes show that structural changes occur in non-monotonic way with operating time at elevated temperatures. For this reason the evaluation of tube degradation can not be based only on the microstructure examinations. The presence of a good correlation between mechanical properties of the catalytic tubes and service conditions, i.e. temperature, time, and internal stress was confirmed. The method for assessing the current degradation level and for predicting residual lifetime of creep-resistant tubes has been established.
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- Category:
- Articles
- Type:
- artykuły w czasopismach recenzowanych i innych wydawnictwach ciągłych
- Published in:
-
Journal of Achievements in Materials and Manufacturing Engineering
no. 43,
pages 244 - 251,
ISSN: 1734-8412 - Language:
- English
- Publication year:
- 2010
- Bibliographic description:
- Łabanowski J.: Evaluation of reformer tubes degradation after long term operation // Journal of Achievements of Materials and Manufacturing Engineering. -Vol. 43., nr. iss. 1 (2010), s.244-251
- Verified by:
- Gdańsk University of Technology
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