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Microstructural aspects of the thermal treatment of Inconel Alloy 600

Journal Article · · Metallography; (United States)
It has been reported that the stress corrosion cracking (SCC) resistance of Inconel 600 can be improved by a thermal treatment in the carbide precipitation regime. Microstructural changes that occur when Inconel 600 is thermally treated in the temperature range 593-870/sup 0/C (1100 to 1600/sup 0/F) have therefore been studied in order to provide a better understanding of the factors controlling the SCC resistance of thermally treated Inconel 600. A total of 13 thermal treatments were used to provide a wide range of grain-boundary microstructures. Microstructural analysis concentrated on three aspects of grain-boundary structure: (1) grain-boundary precipitate morphology, (2) grain-boundary chromium depletion, and (3) grain-boundary segregation. There was a wide range of grain-boundary precipitate morphologies with the associated chromium depletion being prevalent in material annealed at the lower temperatures for the shorter times. Phosphorus was segregated to the grain boundaries in all the thermally treated material. These microstructural observations were correlated with previously published data on the SCC resistance in caustic and lead-doped water environments. The maximum improvement in intergranular SCC resistance correlated with the presence of a semicontinuous grain-boundary carbide precipitate.
Research Organization:
Westinghouse Research and Development Center, Pittsburgh, PA
OSTI ID:
5409684
Journal Information:
Metallography; (United States), Journal Name: Metallography; (United States) Vol. 13:1; ISSN MEIJA
Country of Publication:
United States
Language:
English