Radius ratio estimation and fold situation prediction of the deformation profile in forging–extrusion process

Application of the finite element method in conjunction with abductive network is presented to investigate the geometrical shape of the deformation profile and its related fold defect during forging–extrusion process. The geometrical shape of the deformation profile may be characterized by a parameter of radius ratio that is defined as the ratio of the radius at the equatorial plane to that at the end surfaces of the deformed workpiece. Different geometrical conditions combined with various frictional constraints are taken into account as the process variables in this study. During the forging–extrusion process, several barrels with different radius of curvature may be successively formed along the lateral free surface of the workpiece and the extrusions of the free surfaces of the billet into the aperture surfaces within the dies are accompanied. A finite element based code is utilized to investigate the material flow characteristics resulting in different shapes of the deformation profile, and the abductive network is then applied to synthesize the data sets obtained from the numerical simulation. Finally, the prediction models are established for radius ratio estimation of the barrels and fold occurrence situation judgment under various combinations of process variables.