Upper-bound and finite element analyses of multi-row sprocket during cold semi-precision forging process

The cold semi-precision forging of a multi-row sprocket was investigated using upper-bound (UB) and finite element methods combined with experiments. Based on the design of a new tooth profile for the sprocket, a cold semi-precision forging process and a kinematically admissible velocity field for filling the die cavity were proposed. Using the UB method, the velocity fields of the sprocket billet in the forming process were divided theoretically and calculated. The process of forging a multi-row sprocket was simulated using the FEM package Deform-3D V6.1 to obtain the distributions of the velocity field and the effective stress field in filling the die cavity. Similar to the simulated results, the experiment on cold forging a 5052 aluminum alloy sprocket was successfully performed. By comparing the calculated (UB method), experimental and simulated load-stroke curves, the calculated and simulated results were basically in accordance with the experimental results. The study provides a theoretical foundation for the development of the precision forging of multi-row sprockets.