Microstructural characterization of modified 25Cr-35Ni centrifugally cast steel furnace tubes
HP steels modified with Nb and Nb-plus-Ti, produced in the form of centrifugally cast tubes, were characterized by means of light optical microscopy, scanning electron microscopy (SEM) with secondary and backscattered electron imaging, and transmission electron microscopy (TEM) with energy-dispersive spectroscopy (EDS) and selected area diffraction. A complete description of the phases present in the as-cast, welded, and aged condition was made as a function of the modifying elements. The chromium carbide stoichiometry, secondary precipitation, NbC instability at elevated temperatures, the G-phase transformation, and the effect of Ti on this reaction are discussed. It is indicated that partial transformation of G-phase in the alloy modified with Ti is one of the explanations for the superior creep properties observed in this material.
- OSTI ID:
- 20748674
- Journal Information:
- Materials Characterization, Vol. 49, Issue 3; Other Information: DOI: 10.1016/S1044-5803(03)00013-5; PII: S1044580303000135; Copyright (c) 2003 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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