The Effects of Process-Induced Residual Stress on Rolling Contact Stress of Hard Machined Components

Abstract

Compared with grinding, hard turning is a competitive manufacturing process that in many cases has substantial benefits. The most significant difference between hard turning and grinding is that hard turning may induce a relatively deep compressive residual stress. However, the interactions among the residual stress profile, applied load, and surface material, and their effects on component life in rolling contact are poorly understood. Further, contact stresses and strains are difficult to measure using the current experimental techniques due to the small-scale of the phenomena. A new simulation model of rolling contact has been developed to account for a process-induced residual stress profile. It has shown that distinct residual stress patterns hardly affect neither the magnitudes nor the locations of peak stresses and strains below the surface. However, they have a significant influence on surface deformations. The slope and depth of a compressive residual stress profile are key factors for rolling contact fatigue damage, which was substantiated by the available experimental data. Equivalent plastic strain could be a parameter to characterize the relative fatigue damage. The magnitudes of process-induced residual stress are reduced in rolling contact. The predicted residual stress pattern and magnitude agree with the test data in general. In addition, rolling contact is more sensitive to normal load and residual stress pattern than tangential load.