Influence of the forming angle in cross wedge rolling on the multi-directional forging of crankshafts

In each industrial process for the production of crankshafts a low energy demand and a fast processing time are required. Crankshafts have a very complex geometry and are forged with a high percentage of flash compared to other forging parts. Recent research showed the feasibility of a flashless forging of crankshafts. One way to forge a flashless crankshaft within three steps is to use cross wedge rolling, multi-directional forging and final forging. This paper presents the investigation results regarding the influence of the forming angle α in cross wedge rolling on different parameters at multi-directional forging. First, the state of the art is presented. As a basis for the investigations the process development and tool design of cross wedge rolling and multi-directional forging are described. Afterwards the paper’s results regarding the influence of the forming angle α on flash generation, billet temperatures, forming degree, forming forces and effective strain will be presented as a parameter study. Generally, flash is generated because a rotation-symmetric billet is forced into an asymmetric movement. The influence of an increasing forming angle leads to a higher amount of flash at the bottom of the crankwebs.