The forming characteristics of radial–backward extrusion

The rigid–plastic finite element method is employed for the quantitative analysis of the radial extrusion process combined with backward extrusion. Various variables such as gap size, die corner radius and frictional conditions are adopted as design or process parameters for analysis. The emphasis is focused on the analysis of metal flow into a can and flange. Due to various die geometry and process conditions, the metal flow into a can and flange shows different patterns and its characteristics are well summarized quantitatively in this paper. Experimental data are compared with the simulation results in terms of forming load and the volume ratio of flange to can to verify the usefulness of simulation work. The comparison between experiment and simulation gives good agreement. Extensive simulation work leads to the quantitative relationships between the process conditions, volume ratio of the flange to can, and the size of the flange or can. As expected, the volume ratio of the flange to can increases as the gap size and/or die corner radius increase. However, it is found that the friction condition has little influence on the forming load and the deformation pattern. Under a certain condition of die geometry, can size turns out to be smaller than that of the initial billet. The work presented in this paper could be a good reference for process design in radial–backward extrusion.