A Basic Study on Behavior of The Fatigue Fracture of Tension Bar

인장강봉(引張鋼捧)의 피로파괴거동(疲勞破壞擧動)에 관(關)한 기초적(基礎的) 연구

The fatigue tension tests were performed by use of the specimens without and with a hole, 1/4 crack and 1/2 crack, made of SS41 and S45C steel round bars. Followings were these results. It was shown that in the base metal and the specimen with a hole the fatigue strength of the high strength steel bars was lower than that of the low strength steel bars under the low stress range. It was shown that the fatigue strength of the specimen with a hole was nearly same as that of the base metal, but the fatigue strength of the specimens with the crack was much lower than that of the base metal. It was shown that the fatigue strength of the specimens with the crack was much lower than that of the other specimens under the high stress range.