SUS304ステンレス鋼における下限界近傍真空中高温疲労き裂進展挙動の周波数依存性

概要

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The loading frequency dependence of fatigue crack growth in the near-threshold region in SUS304 stainless steel was investigated using constant K_<max> and ΔK decreasing test method at 350℃, 550℃ and 650℃ in a vacuum below 2.7×10^<-4> Pa. Loading frequency was changed from 30 Hz to 3 Hz and vice versa, and crack growth rates at f=30 Hz and 3 Hz were compared. It was found that crack growth behavior in the region below the conventional threshold value was dependent on the loading frequency. Furthermore crack growth rates per unit hour at f=30 Hz and 3 Hz were compared in order to examine the effect of oxides on the crack surfaces on crack growth behavior. It was suggested that the amount of crack growth was rather time-dependent than cycle-dependent in the region below the conventional threshold in a vacuum.
2007-05-25