FE-simulation-based hot forging process optimization for duplex fork

摘要

Automotive steering knuckle, flange fork, universal joint forks and other components with the fork-shape feature are difficult to forge because of the complex shape of the fork. The duplex fork is a typical forkpiece of automobile transmission shaft, which can be formed by hot forging. But in practical production with one forging step, this part is easily scrapped because of serious folding defect. In order to improve the quality of duplex fork formed by hot forging and decrease the defect rate, a methodology based on orthogonal experiment analysis and FEsimulation was applied to the process parameters optimization of one-step hot forging for duplex forks. Firstly, the finite element simulation tool was used to simulate the original scheme, and it shows that the metal's flow velocity field around the defect area is in disorder. And then, an orthogonal experiment was designed and the flow velocity fields near the folding defect at different process parameters were obtained. By comparing the velocity difference on the section near folding defect at different process parameters, the influence of these parameters including forging temperature, dimensions of die and lubrication condition were analyzed. Finally, optimized process parameters of hot forging for dupleY fork were proposed to reach lower defect rate and better process stability.