Plain fatigue and fretting fatigue behavior of sensitized SUS 304 stainless steel under pressurized hot water at 7.3MPa and 288°C was investigated. The results obtained are summarized below.
1. Fatigue strengths for plain fatigue and fretting fatigue almost coincided under pressurized hot water at 7.3MPa and 288°C.
2. Fretting contact could accelerate nucleation of a localized small SCC crack near the contact region,which can be used as a small SCC precrack for investigating subsequent SCC crack propagation behavior.
3. Small SCC precracks tended not to grow but to coalesce with each other to form a main crack in the direction perpendicular to the loading direction during fatigue cycle.
4. The threshold value for small SCC crack propagation was about 4MPa⋅m1/2, which was significantly low compared to that for long SCC crack. This suggests the importance of small crack problem in SCC.