2D and 3D finite element analysis of a three stage forging sequence

The particular cold forging process presented in this paper is the method used to form a spline shape on the head of an aerospace fastener in three forging blows. The workpiece material was Ti–6AL–4V. The first two figures of this paper illustrate the change in workpiece geometry during the final forging operation. This complicated process is a combination of extrusion (forward and backward) and forging of a very complex spline geometry. The first two stages of the forging operation were modelled using 2D finite element analysis (FEA) because of the symmetry in the workpiece geometry. Between stages two and three (shown in the first two figures), the stresses within the 2D workpiece were imported into a 3D model to enable the simulation of the spline formation. By analysing the strain, damage and flow patterns in all three stages, an in-depth understanding of the operation was obtained. The result from this analysis illustrates the powerful application of modern FEA packages for a large-scale deformation forging process.