Determination of surface and in-depth residual stress distributions induced by hard milling of H13 steel

In the present study, an experimental investigation was conducted to determine the effects of surface texture, cutting parameters and phase transformation on the surface and in-depth residual stress distributions induced by hard milling of AISI H13 steel (50 ± 1HRc) with the coated carbide tools. The results show that the surface residual stress distribution between two adjacent machined lays has the same periodic variational regularity as the surface profiles, which means that the surface residual stress distribution has a high correlation with the machined surface texture. Surface residual stresses in the pick direction are much more compressive than that in the feed direction; at the same time, radial depth of cut and feed are the main cutting parameters affecting surface residual stresses. Very thin white layer forms or even no obvious microstructural alteration appears in the subsurface. Phase transformations of the subsurface material deeply affect the in-depth residual stress distribution, a ‘hook’ shaped residual stress profile beneath the machined surface is generated in which the maximum compressive stresses occur at the depth of 3–18 μm below the surface.