Abstract
In order to investigate the fatigue strength behavior under fully reversed impact torsional load, two types of the impact fatigue tesing machines were newly developed. By using these testing machines, a series of experiments were carried out on a structural alloy steel JIS. SCM435.
The following characteristics of impact torsional fatigue strength behaviors were revealed : (1) the fatigue strength of the plain specimen in impact fatigue is higher than that in non-impact fatigue in the entire range of this experiment ;(2) the fatigue strength of the hole-notched specimen in impact fatigue shows a trend to become lower comparing with the results in non-impact fatigue in high stress cycles region ; (3) the crack growth rate in impact fatigue is lower than in non-impact fatigue.
