On the residual life assessment of high-speed railway axles due to induction hardening

Abstract

Surface hardening treatment can significantly increase the hardness of axle surface and introduce negative residual stress field into the axle. This work proposed an integrated stress rebuilding strategy of unit pressure and proportional integral approach to conduct the residual life prediction of an induction hardened axles and a load spectrum. A large crack aspect ratio a/c = 0.9 at the transition was used to predict the residual lifetime. It is well found that the hardened layer can provide a considerable fatigue resistance. Moreover, the critical stress region transfers to the inside of the axle or beneath the hardening layer rather than the free surface. Due to compressive residual stress, the evolved crack shape of hardened axles is completely different from original axles, showing a large aspect ratio. Totally, surface strengthened axles can acquire a prospective extended residual life.