2014 年 100 巻 8 号 p. 974-983
In order to reduce the weight of the suspension springs by increasing the strength level of the steels used, improvement of the corrosion fatigue property is the most important issue. This study investigated, the effect of residual stress, artificial corrosion pit depth and diffusible hydrogen on rotary bending fatigue properties of specimens after double shot and triple shot peening. The following conclusions were obtained:
(1) Fatigue limits of specimens having the artificial corrosion pit of 250 μm depth with and without the charged hydrogen are improved remarkably by the triple shot peening.
(2) Fish-eye fatigue fracture with an inclusion as the fatigue crack initiation site occurs frequently due to the charged hydrogen.
(3) A good relationship between fatigue limit after shot peening and compressive residual stress at the bottom of the artificial corrosion pit is obtained regardless of the depth of the artificial corrosion pit.
