Design Method of Strip Would Die for Metal Extrusion Process Based on Fatigue Theory

In this paper, failure of die for metal extrusion process is discussed and failure types of the dies are presented firstly. A novel pre-stressed structure named after strip would die is brought forward, which is pre-pressed by thin high-strength steel strips and can provide a radial pre-stress on the external surface of die. The detailed structure of the strip would die is presented. The strip would die is designed according to the iso-strength theory, which means that the steel strip and the die body have the same fatigue lives. Based on the fatigue theory, Analytical model of the die body and the strip is established. Using numerical method and the analytical model, number of the strip layers, pre-stress and the winding tension are determined. Therefore, the design method of strip would die for metal extrusion process based on fatigue theory can be established.