Rotary bending fatigue tests were carried out on laser peened SUS316L and AC4CH with a pre-crack to investigate the effect of laser peening treatment on fatigue crack propagation properties in different f.c.c. materials. As the results, the surface crack propagation was prevented and the fatigue strength was improved in both materials. But there were differences in surface crack initiation life and restraint of surface crack growth in two materials. It is assumed that the reasons of the difference are the surface roughness and the surface hardness effects by LP treatment on SUS316L and AC4CH.
