片状黒鉛鋳鉄の疲労における切欠感度
1988 年 54 巻 507 号 p. 1962-1966
詳細
1988 年 54 巻 507 号 p. 1962-1966
Zero-to-tension fatigue tests were performed on flat and notched bars of three gray cast irons, and the notch sensitivity was discussed based on the stress distribution obtained by considering the nonlinear behavior of the material. In flake graphite iron, the notch factor for notches with form factors 1.6 and 2.8 was 1.1-1.2 near the fatigue limit, this is higher than the notch sensitivity in static strength, but lower than that at fatigue in ductile iron. Calculated stress under the notch exceeded the fatigue strength of flat specimen down to 0.6-1.4 mm depth depending on the number of cycles to failure, matrix ductility, and notch radii. The minimum depth was 1/2-1/3 of this value in static rupture, equal to 1-2 graphite eutectic cell diameters, and was considered a minimum stress depth for crack formation.
