Ductility Improvement of Drawn High-carbon Steel Wire by Alternate Wire Drawing

Drawing a high-carbon steel wire increases the strength of the wire but significantly reduces its ductility. In addition, leading to the delamination, which is characteristic of a high-carbon steel wire and occurs in wires with reduced ductility, appears, and this is the biggest factor in the inhibition of high-strength wire. We investigated the possibility of suppressing delamination by using the alternating wire drawing process, which suppresses additional shear strain during drawing and increases ductility. First, we conducted tension tests on alternately and conventionally drawn wire to investigate changes in mechanical properties, with alternately drawn wire at a breaking strain of 1.9% and conventionally drawn wire at a breaking strain of 1.5%. Next, we conducted a torsion test, as stipulated in the Japanese Industrial Standards, and confirmed that the alternate wire drawing process suppressed the delamination. We also examined whether the alternate wire drawing process suppressed axial tensile residual stress on the wire surface by using the slit method and Finite element method analysis.