Influence of residual stress depth distribution on lifecycle behaviour of AISI4140

摘要

Surface integrity has a major influence on the fatigue behaviour of metallic components.Using deep rolling,the residual stress state can be influenced to a high degree under consideration of the contact stresses between workpiece and tool.This can be used to tailor the residual stress state to improve the fatigue and lifecycle behaviour of metallic componetens.To combine the existing knowledge about the relationship between mechanical load during deep rolling and the residual stress state and lifecycle experiments,a previously developed model is applied to quenched and tempered A1S14140 components to generate parts with similar surface residual stresses but different depth distributions.The parts are stressed using rotating bending tests and the influence of the residual stress state on the residual stress relaxation and lifespan is evaluated.The results show that it is possible to influence the residual stress state to a targeted profile by the adaption of the machining parameters.The performed deep rolling experiments result in two cases:Both parameter variations result in similar compressive surface residual residual stresses.Parameter set A(high pressure,low overlap)generates a higher residual stress penetration depth and a higher roughness,while set B(low pressure,high overlap)generates a lower penetration depth and a smoother surface.The rotating bending tests result in a higher lifetime and a lower residual stress relaxation for parameter set A.