Cross wedge rolling and bi-directional forging of preforms for crankshafts

Abstract

Preforming is an essential step in flashless forging processes. This paper describes the development of a four stage process chain for flashless forging of a two cylinder crankshaft with pin and flange. The process consists of cross wedge rolling, lateral extrusion, bi-directional forging and final forming, with cross wedge rolling being the essential step. The finite-element-analysis (FEA) performed with the software Forge 3 and experimental tests are executed with different process parameters, like billet and tool temperature, rolling velocity and steel. To reduce process steps, like lateral extrusion, a direct combination of cross wedge rolling and bi-directional forging is analysed with FEA-software Forge 3 for a one cylinder crankshaft without pin and flange. The one cylinder crankshaft is selected to reduce development effort. The results of the FEA give suitable forming angles α for cross wedge rolling and several geometric parameters for a modification of the bi-directional tool.