Inhomogeneous deformation and residual stress in skin-pass axisymmetric drawing

Skin-pass drawing is usually conducted in the final stage of wire, rod or shaped-section drawing or shape rolling. It helps improve shape accuracy and reduce residual stress of the drawn or rolled workpieces. However, its characteristic low reduction induces large Δ-parameter, and causes significant inhomogeneous deformation in the workpiece. In this work, finite-element software DEFORM 2D was utilized to investigate the effect of Δ-parameter on inhomogeneous deformation and residual stress of mid-carbon steel through various combinations of area reduction and die semi-angle. The effect of the friction was also investigated. The results showed that the inhomogeneity factor of effective strain decreased with area reduction and increased with die semi-angle and friction. The level of inhomogeneous deformation could be reduced by drawing with small die semi-angle, and the influence of the friction was only substantial near the surface of the drawn workpiece. The axial and circumferential residual stresses would approach to compressive on the drawn surface in extreme light reductions.