SUS304鋼の高温疲労き裂伝ぱ挙動に及ぼす予クリープ損傷の影響
1988 年 37 巻 414 号 p. 322-327
詳細
1988 年 37 巻 414 号 p. 322-327
In order to investigate the effect of previous creep damage on the fatigue crack propagation behavior at elevated temperature, stress-controlled fatigue crack propagation tests were carried out at 650°C on SUS304 steel.
The results obtained were summarized as follows:
(1) For the fatigue crack propagation test, the data of crack propagation rate could be arranged by ΔJ. As a result, the crack propagation rate of the previously creep-damaged material was half of that of the virgin material when the degree of previous creep damage and the creep stress level were larger than some critical values. This may be caused by the change in microstructure of the material, that is, the introduction of the subgrain boundaries due to the strong cell formation during the previous creep loading.
(2) For the creep-fatigue test, the data of crack propagation rate could be arranged by ΔJc. As a result, the crack propagation rate of the previously creep-damaged material was almost same as that of the virgin material. It seems that the crack propagation rate was not affected by the change in microstructure inside the grain due to the previous creep loading because the creep-fatigue crack propagated along the grain boundaries.
