抄録
Tension-compression fatigue tests were carried out by using high strength steels with different strength levels and the endurance limit diagrams were obtained.
The main results are as follows:
(1) The shape of the endurance limit curves of various high strength steels differed largely depending on their strength level. It also differed when the strength level was varied by changing tempering temperature for the same material.
(2) The endurance limit curves of the steels with tensile strength higher than 150kg/mm2 abruptly decreased with the increase of mean stress in the region from the completely reversed tension-compression to the pulsating tension, and when the mean stress was further increased and exceeded a certain value, the curve became flat at low stress amplitude level, and was independent of mean stress.
(3) The endurance limit curves of the steels with tensile strength lower than 150kg/mm2 showed the same tendency as those of the ordinary carbon steels.
