Abstract
The maximum crack size rendered harmless on the weld toe of type 316 stainless steel welded joint by conducting Portable Pneumatic needle-Peening (PPP) was estimated focusing on stress intensity factor of crack tip. Stress intensity factor of external force and that of residual stress introduced by conducting PPP were calculated by FEM analysis. Then, it was found that the maximum crack size rendered harmless is 1.44 mm by comparing the stress intensity factor of semi-circular slit and the threshold stress intensity factor. The estimate value coincided with the result of bending fatigue test.
