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

To investigate fatigue properties of a low activation ferritic steel (9Cr-2 W steel, JLF-1), low cycle fatigue tests were performed in air at room temp erature 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 unt il the final failure, though the plastic strain range did not change signif icantly. Tensile peak stresses in hysteresis curves measured at around half the number of cycles to failure depended on the total strain range. The dr op in the peak stress by the cyclic strain-softening increased with decreas ing total strain range. The regression curve of the total strain range agai nst the fatigue life was formulated using the Manson-Coffin equation and th e fatigue life of JLF-1 steel was compared with that of 8Cr-2W steel. (C) 2 000 Elsevier Science B.V. All rights reserved.