Residual Stresses in an Induction Hardened Gear Tooth Mapped by Synchrotron X-ray Diffraction

Abstract

Surface hardening in components subjected to severe contact loading, such as gears, is accompanied by the generation of a layer of residual stress. Compressive residual stresses in surface engineered components are often induced deliberately to provide improved toughness and wear resistance. However, a near-surface layer of compressive stress often generates a balancing region of tensile stress deeper within the component, which may accelerate damage in this region and promote failure. To quantify the effect of treatment on the stress distribution, residual strains in an induction hardened gear tooth were mapped using high energy synchrotron diffraction on Station 16.3 at SRS, Daresbury. White beam mode and an energy dispersive detector were used, and two components of strain and stress in the plane transverse to the gear axis were evaluated.