Numerical Study of the Workpiece Rotation Effect on the Strain and Residual Stress Distribution in the Cold Radial Forging Process

Radial forging is an open die forging process used for reducing the diameters of shafts, tubes, stepped shafts and axels, and for creating internal profiles in tubes. In this study, the effect of the workpiece rotation (the circumferential feed) on the strain and residual stress distribution in the inner surface of the tube in the cold radial forging process is investigated using nonlinear three dimensional finite element modeling. To verify the model, the predicted radial forging load is compared with the published experimental data which shows a good agreement. It is shown that for achieving a more favorable residual stress distribution in the workpiece inner surface, the rotation angle associated with each stroke should be reduced. Furthermore, a total rotation angle of 90° seems to be sufficient for finalizing the strain and residual stress distribution in the workpiece inner surface and using additional rotation is just a waste of time and energy in this respect.