Hard turning versus grinding - the effect of process-induced residual stress on rolling contact

Compared with grinding, hard turning may induce a relatively deep compressive residual stress while still achieving an equivalent surface finish. Although it is generally agreed that deep compressive residual stresses are beneficial to component life in rolling contact, the interactions between the residual stress profile, applied load, and surface material are poorly understood at present. With the input of process-induced residual stress profile instead of one point "surface" residual stress, a simulation model of rolling contact for hard-machined components has been developed by directly modeling the interaction between the roller and the machined surface, rather than moving the assumed Hertzian pressure and tangential surface traction across the surface of the traditional method. The equivalent plastic strain could characterize relative fatigue damage under the influence of process-induced residual stress. The slope of a compressive residual stress profile as well as its depth were identified as key factors for rolling contact fatigue damage. Rolling contact tend to reduce the initial compressive residual stress. The predicted residual stress pattern and magnitude agree with the test data in general. The increase of friction dramatically increases the magnitude of peak compressive residual stress but not its location. The normal load shifts the location of peak compressive residual stress much deeper below the surface. (C) 2003 Elsevier B.V. All rights reserved.