danielshaw
Ansys Employee

Probably.  SN is only valid for high-cycle fatigue (HF) using elastic stresses.  A predicted fatigue life for a ductile metal of only 4392 cycles is probably indicating low-cycle fatigue (LCF) produced by plastic strains.  The predicted life of 4392 cycles is probably conservative, but if you want a more accurate life prediction, you should use EN.