Changes in electromagnetic properties during thermal aging of duplex stainless steel
- Mitsubishi Heavy Industries, Ltd., Takasago (Japan)
- Mitsubishi Heavy Industries, Ltd., Kobe (Japan)
Cast duplex stainless steels used in primary pressure-boundary components of pressurized water reactors have been found to be susceptible to thermal aging embrittlement at reactor operating temperature. Extensive studies and investigations on the aging mechanism itself have been conducted in order to evaluate end-of-life aging. Three types of testing employing electromagnetic techniques, i.e., electric resistivity testing, coercivity measurement testing and Barkhausen noise testing have been investigated in order to search for an effective nondestructive method to evaluate the thermal aging of cast duplex stainless steels. Changes in impact strength, micro-Vickers hardness of ferrite phase and electromagnetic properties were studied in two CF8M materials with differing ferrite content that were subjected to long-term heating. The values measured using the electromagnetic techniques were correlated with Charpy-impact energy values and the observed microstructural changes were used to assess the potential that these techniques have for use as NDE methods. Each of these techniques was found to be sensitive to different processes that occur during thermal aging. Therefore, an integrated method using these techniques is now under development.
- OSTI ID:
- 86148
- Report Number(s):
- CONF-9505104--; ISBN 0-87170-548-6
- Country of Publication:
- United States
- Language:
- English
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