Abstract
Sintered ferrous alloy gears are used in wide engineering fields. However, it is difficult for them to be applied to the parts loading at high stress levels, because their strength is poorer than that of the wrought materials. In this study, sintered ferrous alloy gears were rolled and their tooth root bending fatigue strengths were investigated. The effect of rolling conditions on the porosity distribution and hardness at tooth root, and the tooth root bending fatigue strength were determined. As the amount of stock rolled was increased, the porosity of the vicinity of the surface was decreased and the hardness was increased, and also the tooth root bending fatigue strength was increased to certain level, and then the fatigue strength was decreased. This seemed to be due to the shaving when the gear was rolled.
