Aging of cast duplex stainless steels in LWR systems
A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. The existing data are evaluated to determine the expected embrittlement of cast components during the operating lifetime of reactors and to define the objectives and scope of the investigation. This presentation describes the status of the program. Data for the metallurgical characterization of the various cast stainless steels used in the investigation are presented. Charpy impact tests on short-term aged material indicate that CF-3 stainless steels are less susceptible to embrittlement than CF-8 or CF-8M stainless steels. Microstructural characterization of cast stainless steels that were obtained from Georg Fischer Co. and aged for up to 70,000 h at 300, 350, and 400/sup 0/C reveals the formation of four different types of precipitates that are not ..cap alpha..'. Embrittlement of the ferrite phase is primarily due to pinning of the dislocations by two of these precipitates, designated as Type M and Type X. The ferrite phase is embrittled after approx. 8 y at 300/sup 0/C and shows cleavage fracture. Examination of the fracture surfaces of the impact-test specimens indicates that the toughness of the long-term aged material is determined by the austenite phase. 8 figures, 3 tables.
- Research Organization:
- Argonne National Lab., IL (USA)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 6410369
- Report Number(s):
- CONF-8410142-38; ON: DE85003023
- Country of Publication:
- United States
- Language:
- English
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Aging degradation of cast stainless steel
Related Subjects
220200* -- Nuclear Reactor Technology-- Components & Accessories
36 MATERIALS SCIENCE
360103 -- Metals & Alloys-- Mechanical Properties
AGING
ALLOYS
CHARPY TEST
CHROMIUM ALLOYS
CORROSION RESISTANT ALLOYS
CRYSTAL STRUCTURE
DESTRUCTIVE TESTING
EMBRITTLEMENT
FRACTURE PROPERTIES
HIGH TEMPERATURE
IMPACT TESTS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MATERIALS TESTING
MECHANICAL PROPERTIES
MECHANICAL TESTS
MICROSTRUCTURE
REACTOR MATERIALS
REACTORS
STAINLESS STEELS
STEELS
TESTING
WATER COOLED REACTORS