Abstract
This paper presents a study on optimum profile of hardened layer for bending fatigue strength of induction hardened gears. The measurement of hardened layer and the bending fatigue test were carried out for induction hardened gears made of as-rolled and thermally refined S35C and S45C steels, and then profiles of hardened layer and S-N curves were obtained. Effects of the pre-treatment, the heating time, the electric power and the frequency on profile and micro structure of hardened layer of induction hardened gears were examined. The relationship between the bending fatigue strength and the profiles of hardened layer was determined. An optimum profile of the hardened layer for the bending fatigue strength of induction hardened S35C and S45C steel gears were indicated.
