Creep-Fatigue Behavior with Hold Type for High Cr Martensitic steel

9Cr steel has high strength and high thermal conductivity, low thermal expansion, and high resistance to the swelling by irradiation. 9C steel is applied to structures of future reactor such as cladding of nuclear fuel, heat exchanger, and reactor pressure vessel and pipe. Thermal fatigue by temperature gradient due to heat-up and cool down and creep during normal operation are important factors to limit structural life. Interaction of fatigue and creep is more damaged than fatigue and creep which are applied separately. In this study, creep-fatigue behaviors of 9Cr steel with hold type and hold time are evaluated