Numerical study on the evolution of surface defects in wire drawing

In this study, a three-dimensional finite element analysis for multi- or single-pass wire drawing was carried out in order to evaluate the deformation behavior of various surface defects, such as longitudinal, transverse, oblique, and round, introduced during the manufacturing processes. For numerical simulations, a free surface contact treatment algorithm was employed to suppress node penetration by applying a penalty method. Simulation results were compared with the experimental data obtained by optical microscopy for multi-pass drawing samples of the medium carbon steel wire with a longitudinal round-type defect in terms of variation of the load requirement and evolution of the cross-sectional shape of the surface defect. Additional numerical studies were carried out to investigate changes of cross-sectional shapes of various surface defects depending on stress distributions in the single-pass wire drawing. It was found that the radial and circumferential stress components determined the final shape and aspect ratio of the defect. The current numerical approach can be helpful in determining a guideline to assess the acceptability of the surface quality of the drawn wire for the secondary manufacturing process based on the available data in the literature.