球状黒鉛鋳鉄の高温疲労強度について
1974 年 23 巻 251 号 p. 640-645
詳細
1974 年 23 巻 251 号 p. 640-645
The rotating bending fatigue tests were perfomed on the specimens of nodular cast iron with unnotch, semicircular notch and 60°V-notch at room temperature, 150°C, 300°C, 400°C, 550°C, and 800°C with the frequency of 3600rpm. Their values of fatigue strength were obtained at 107 cycles.
The results are as follows:
(1) The fatigue strength of the unnotched specimen decreases with the rising test temperatures. At about 400°C, however, the fatigue strength takes the slightly high value due to the blue brittleness. Beyond the range of 500°C to 550°C, the fatigue strength decreases rapidly.
(2) The fatigue strength of the notched specimens decreases with the rising test temperatures. At about 300°C to 400°C, however, the fatigue strength shows a near constant value. Beyond 400°C, the fatigue strength decreases rapidly.
(3) The value of fatigue notch factor gradually increases with the elevating temperatures above room temperature and then increases rapidly beyond about 400°C to 500°C.
