Abstract: In order to solve the problem of peeling off on the surface of the camshaft,it is necessary to improve the wear resistance and mechanical properties of the parts,especially the uniformity of medium frequency quenching,in order to improve the fatigue strength.By using multiple preheating cycles and scanning heating,the depth of the hardening layer in the lifting range is increased without deepening the hardening layer at the cam tip,reducing the influence of negative curvature on the heating efficiency within the range of current penetration depth,and significantly improving the uniformity of the hardening layer and surface stress state of high-power irregular camshaft.