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Title: Microstructural changes caused by yttrium addition to NbTi-modified centrifugally cast HP-type stainless steels

Abstract

Centrifugally cast heat-resistant HP stainless steels are particularly suitable for applications where service conditions comprise high temperatures and aggressive environments; thus, they are extensively used in reformer furnaces, in which hydrogen production takes place. The demand for better performance has motivated developments in these steels. The addition of Nb and Ti as microstructural modifiers has proved successful in providing a more stable microstructure. In this work yttrium was added to centrifugally cast NbTi-modified HP steels. It was observed that its presence increased the level of fragmentation of the chromium carbides, a positive aspect for creep resistance. The main cause of the fragmentation is the formation of yttrium carbides, which serve as heterogeneous nucleation sites for the other carbides. One of the tubes, with a lower titanium content, showed the best creep performance among those tubes studied owing to the presence of a smaller volume fraction of the deleterious G phase.

Authors:
 [1];  [2];  [3];  [3];  [4]
  1. Federal University of Rio de Janeiro (UFRJ), C.P. 68505, Ilha do Fundao, Rio de Janeiro (Brazil). E-mail: fcnunes@gmail.com
  2. Federal University of Rio de Janeiro (UFRJ), C.P. 68505, Ilha do Fundao, Rio de Janeiro (Brazil)
  3. Free University of Brussels, C.P. 194/03, Av. F. D. Rooselvelt, 50, B-1050, Brussels (Belgium)
  4. Metallurgical Consulting Services, P.O. Box 5006, Saskatoon, SK, S7K 4E3 (Canada)
Publication Date:
OSTI Identifier:
21003528
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 58; Journal Issue: 2; Other Information: DOI: 10.1016/j.matchar.2006.04.007; PII: S1044-5803(06)00104-5; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CASTING; CASTINGS; CHROMIUM CARBIDES; CREEP; FRAGMENTATION; FURNACES; HEAT; HYDROGEN PRODUCTION; MICROSTRUCTURE; NUCLEATION; PERFORMANCE; STAINLESS STEELS; TITANIUM; YTTRIUM; YTTRIUM ADDITIONS; YTTRIUM CARBIDES

Citation Formats

Nunes, F.C., Almeida, L.H. de, Dille, J., Delplancke, J.-L., and Le May, I. Microstructural changes caused by yttrium addition to NbTi-modified centrifugally cast HP-type stainless steels. United States: N. p., 2007. Web. doi:10.1016/j.matchar.2006.04.007.
Nunes, F.C., Almeida, L.H. de, Dille, J., Delplancke, J.-L., & Le May, I. Microstructural changes caused by yttrium addition to NbTi-modified centrifugally cast HP-type stainless steels. United States. doi:10.1016/j.matchar.2006.04.007.
Nunes, F.C., Almeida, L.H. de, Dille, J., Delplancke, J.-L., and Le May, I. Thu . "Microstructural changes caused by yttrium addition to NbTi-modified centrifugally cast HP-type stainless steels". United States. doi:10.1016/j.matchar.2006.04.007.
@article{osti_21003528,
title = {Microstructural changes caused by yttrium addition to NbTi-modified centrifugally cast HP-type stainless steels},
author = {Nunes, F.C. and Almeida, L.H. de and Dille, J. and Delplancke, J.-L. and Le May, I.},
abstractNote = {Centrifugally cast heat-resistant HP stainless steels are particularly suitable for applications where service conditions comprise high temperatures and aggressive environments; thus, they are extensively used in reformer furnaces, in which hydrogen production takes place. The demand for better performance has motivated developments in these steels. The addition of Nb and Ti as microstructural modifiers has proved successful in providing a more stable microstructure. In this work yttrium was added to centrifugally cast NbTi-modified HP steels. It was observed that its presence increased the level of fragmentation of the chromium carbides, a positive aspect for creep resistance. The main cause of the fragmentation is the formation of yttrium carbides, which serve as heterogeneous nucleation sites for the other carbides. One of the tubes, with a lower titanium content, showed the best creep performance among those tubes studied owing to the presence of a smaller volume fraction of the deleterious G phase.},
doi = {10.1016/j.matchar.2006.04.007},
journal = {Materials Characterization},
number = 2,
volume = 58,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}