Abstract
In order to investigate the influence of shot peening on the surface durability of case-hardened steel gears, the case-hardened steel gears shot-peened with different shot velocity and shot diameter were fatigue tested using a power circulating type gear testing machine. The hardness, the compressive residual stress and the surface roughness of the gears increased by the shot peening. The failure mode of all the test gears was pitting. The surface durability of the gear shot-peened under medium condition in this experimental range was higher than that of non-peened gear, on the other hand those of lightly or strongly shot-peened gears were lower. Judging from the p_<max>-N curves and also the [A(δ_y/√<3> HV)]_<max>-N curves, it is proposed in this experimental range that the medium shot peening condition, that is, 60m/s shot velocity and 0.6mm shot diameter, should be selected in order to improve the surface durability of case-hardened steel gears.
