Experimental investigation and analysis of the influence of tool edge geometry and work piece hardness on surface residual stresses, surface roughness and work-hardening in hard turning of AISI D2 steel

Abstract

Surface integrity of the machined component significantly affects its in-service performance in terms of fatigue life and resistance to corrosion. Residual stresses, work hardening, microstructure alterations and surface roughness are the major issues that constitute the surface integrity of a machined surface which are a resultant of the plastic deformation. The current study attempts to investigate the effect of the different tool edge geometries and the process parameters in CBN hard turning of AISI D2 steel on the tri-axial surface residual stresses, surface roughness and work hardening in the machining affected region. XRD in conjunction with nano indentation has been utilized for measurement of the surface integrity parameters. The behavior of the residual stresses is correlated to the input parameters. Sensitivity of the tri-axial stresses to the input parameters is obtained by Monte Carlo Simulation and optimum ranges of the input parameters and the probabilities of inducing compressive stresses have been determined. The sensitivity analysis indicates that the axial residual stress has maximum sensitivity to depth of cut while the radial and circumferential residual stresses and surface roughness are most sensitive to feed rate. The certainty analysis indicates that machining with light honed tool edge geometry in the low to moderate range of process parameters induces a compressive state of residual stresses and better surface quality.