Abstract :
In the past twenty to thirty years, metal forming technology has been developed in a tangible speed never seen before, of which, the application of computer simulation turns out to be the most declared token. Compared with conventional metal forming technology, the modern processing techniques put much emphasis on the design of blank and die and the control of material plastic flow. The trial-and-error method based on past experience can no longer meet the requirements therefore put forward. In this paper, a quasi thermal-mechanical coupled rigid visco-plastic model for bearing ring forging is created on the bases of metal forming principle and nonlinear FEM theory. The key problems for valid forging simulation are investigated and influences of the main factors such as strain rate, forging force, punch rounding, initial temperature of die and forging pieces are studied for forging process control. Simulation and test results of the correlations between pre-forming pattern of forging piece and forging force level indicate that the work piece forming pattern in the die during the later stage of the forging process tends to cause great influence on the punch force level and final forging quality. Based on this, optimal criteria for the pre-forming pieces are set up and an optimal pre-forming forging blank is designed, which gives improved forging quality and reduction of forging force level by more than 50%.
