Effect of die geometry on residual stress level present after bar drawing

A new drawing die designed to reduce the residual stresses in bar after dra wing is presented. The die design consists of two consecutive straight tape r portions, and the outlet portion has a very small die angle. The marked b eneficial effect of adding the outlet portion was predicted by finite eleme nt modelling (FEM), and subsequently verified by measuring the residual str esses in drawn bars. The optimum range of the outlet die angle was determin ed using FEM. The new design requires a slightly longer die length than the conventional one, but it is short enough to be adopted in current producti on lines.