Wire drawing dies with prescribed variations of strain rate

摘要

The strain-rate variation experienced by a metal-matrix composite or aluminum alloy of the 2xxx/7xxx series as it flows through the die is an important factor in the success of the drawing process. This paper presents an efficient method incorporating the yield criterion and the velocity field with the die angularity that can give an accurate prediction of the die shape based on the prescribed strain rate. A transition zone is introduced to eliminate the unfavorable influence of the inlet die angle on the strain-rate distribution. Numerical integration of only one ODE is needed to solve the die shape. The influences of the die angle, reduction, aspect ratio of the die, interfacial friction and drawing velocity on the die geometry are studied. Different material properties such as hardening due to strain and strain rate are also considered. FEM simulation of the strain-rate distribution and drawing stress is performed to validate the new method.