Fatigue life and fatigue crack propagation behavior of JLF-1 steel

The objective of this study is to investigate fatigue life and fatigue crack propagation behavior in the reduced activation ferritic steel JLF-1. The experiment of fatigue life for JLF-1 steel have been carried out for the stress ratio R=0 at room temperature and 400 °C. The fatigue crack propagation behavior of the JLF-1 steel was investigated by the constant amplitude loading test for the stress ratios R=0.1, 0.3 and 0.5, respectively. The effects of stress ratios and specimen size on the fatigue crack growth behaviors for JLF-1 steel were discussed within the Paris law. The fatigue life test performed under the room temperature and 400 °C. At room temperature, the fatigue limits of longitudinal and transverse direction to the rolling direction were 480 and 490 MPa at 1×107 cycles, respectively. Also, at 400 °C, the fatigue limits of longitudinal and transverse direction to the rolling direction were 400, 416 MPa at 1×107 cycles, respectively. The base material of JLF-1 steel showed the isotropic behavior in fatigue properties of the rolling direction and the test temperature. The fatigue crack propagation rate of a half size specimen was similar to that of a full size specimen at the stress ratios of 0.1, 0.3 and 0.5, respectively. The fatigue crack propagation behavior of this material can be evaluated by using half size specimens.