Low cycle fatigue properties of a low activation ferritic steel (JLF-1) at room temperature

To investigate fatigue properties of a low activation ferritic steel (9Cr–2W steel, JLF-1), low cycle fatigue tests were performed in air at room temperature under axial strain control for a complete push–pull condition. The strain rate was 0.4% s−1. Cyclic strain-hardening was observed within the initial 20 cycles, and then cyclic strain-softening occurred gradually until the final failure, though the plastic strain range did not change significantly. Tensile peak stresses in hysteresis curves measured at around half the number of cycles to failure depended on the total strain range. The drop in the peak stress by the cyclic strain-softening increased with decreasing total strain range. The regression curve of the total strain range against the fatigue life was formulated using the Manson–Coffin equation and the fatigue life of JLF-1 steel was compared with that of 8Cr–2W steel.