Die design was optimized for suppressing the void growth in multi-pass drawing. The void index to evaluate the void fraction in multi-pass drawing was first proposed, based on the well-known equation to predict the fracture limit in cold working. Using finite element analysis, the influence of die geometries on the void index was investigated and dies were designed to have the effect of suppressing void with the least minimum die length. A series of experiments was then carried out to verify the validity of the numerical analysis. The densities of drawn bars were measured and voids in microstructures were observed to verify the validity of the proposed void index.
KomoriK.Simulation of chevron cracks in drawing. J. JSTP, 1996, 37 (426), 755–760.
3.
GursonA. L.Continuum theory of ductile rupture by void nucleation and growth: Part I. Yield criteria and flow rules for porous ductile media. Trans. ASME, J. Engng Mater. Technol., 1997, 99–1, 2–15.
4.
NakagiriA.MatsukawaK.WatanabeS.SasagawaY.Influence of die-wire contact length ratio on chevron crack and optimum drawing condition in wire drawing. J. JSTP, 1997, 39 (447), 380–384.
5.
AvitzurB.New, improved criterion for the prevention of central burst in wire drawing and extrusion. Wire J., November 1974, 77–86.
6.
KubokiT.AkiyamaM.NeishiY.KurodaK.Effect of final drawing with light reduction on the levelling of residual stress distribution in cold bar drawing. Proc. Instn Mech. Engrs, Part C. Journal of Mechanical Engineering Science, 2000, 214 (C11), 1389–1400.
7.
KubokiT.AkiyamaM.NeishiY.KurodaK.A study of the effect of die geometry on the residual stress levels present after bar drawing. Ironmaking and Steelmaking, 2001, 28 (1), 65–71.
