Die fatigue life improvement through the rational design of metal-forming system

In metal-forming industries, die is an important tool for fabrication of metal-formed products. Die service life, which is defined as the maximum product number produced by die before it fails, and die performance directly determine the quality of metal-formed product and production cost. In cold forming process, die service life basically refers to the die fatigue life. The die fatigue life is determined by the design of metal-formed product and die, forming process configuration, die stress and the entire metal-forming system. In this paper, a methodology for optimization of die fatigue life is developed via the rational design of metal-forming system in such a way that the die stress is optimal and further the die design in terms of its service life is the best. To realize this thought, the S–N approach is employed for evaluation of die fatigue life. The die stress is first identified via the integrated simulation of billet plastic flow and the die deformation during the forming process. The die stress is then optimized via the rational design of the combination of metal-formed product, die and process configuration. The optimal die life is thus determined. Furthermore, a framework for implementation of this methodology is developed and case studies are used for verification and validation of the developed methodology.