き裂状表面欠陥を有するステンレス鋼の疲労限度および下限界応力拡大係数範囲に及ぼす過大予荷重の影響

抄録

The effects of overload on the fatigue limit and threshold stress intensity factor range (Δk_th) of SUS316 were studied. Tensile or compressive overload were applied to the bending fatigue test specimens with a small crack-like surface defect and fatigue tests were carried out to determine the fatigue limit and Δk_th. It was found that the Δk_th increased by tensile overloading. The increasing rate of Δk_th in the CT specimen is larger than that in the bending fatigue test specimen with a small crack-like surface defect. Thus, the crack size effects on the improvement of Δk_th after overloading were observed. The results are discussed from the viewpoint of fracture mechanics.