Abstract
In the previous study on pipe with wall thinning, wall thinning part has been assumed as smooth. Therefore the effects of multi surface pits which occurred in the wall thinning part on low cycle fatigue strength of pipes are not clarified. In this study, plane bending fatigue test was performed using the specimen having multi surface pits and their effects on low cycle fatigue strength for pipes were evaluated. Consequently, it was found that the effect of pits on the number of cycle to failure(N_f) was small when N_f was less than 10^3. The universal slope method gave a safety evaluation of N_f for specimens having pits.
