Analytical and FEM Investigations on Boss Forming Process by Compression-drawing Method

In plate forging process, one of the major causes for dimple defect is large processing load with the nonuniform material flows of local plastic deformation. In the present work, a new solid boss forming process named compression-drawing method was proposed with a lower forming load. The theoretical formula of the radii of separation flow was deduced based on slab method, in which the radii of separation flow decreases gradually as the bottom thickness decreases. The finite element method (FEM) with DEFORM-3D was used to investigate the solid boss forming process. The results show that the boss height is found insufficient when the punch pressure is under 200KN while the fracture behavior occurs as the punch pressure reaches 670KN approximately. The FEM calculations are well agreement with the experimental results.