Abstract
A numerical investigation by axi-symmetric finite element method (FEM) assumed the die deformation was carried out on diameter changing in a bar and a wire under cold-drawn through a wire drawing die. The mechanism of diameter changing was made clear and the factors influencing diameter were investigated. As a result, the final diameter of drawn bar is depend on the die expansion by contact pressure, the diameter decreasing at bearing area (Under shoot effect) and the spring back during drawing and unloading. The most influencing factors which are usually changed in field operation are approach semi angle, back tension, reduction and F value.
