炭素鋼焼なまし材の回転曲げ疲労強度に及ぼす表面加工層の影響

抄録

In order to study the effect of surface layers formed by lathe turning on the fatigue strength, rotating bending fatigue tests of an annealed carbon steel were carried out. The results obtained are as follows. The fatigue limit of annealed carbon steel specimens turned by a cermet tool, increases by 34 % in comparison with electropolished specimens. Because of work hardening and compressive residual stress in the surface of the specimen formed by lathe turning, crack initiation was restrained. In the specimens formed by turning, a long crack beyond the worked layer size propagated with almost the same speed as that of a crack in the nonworked layer.