Control of Material Flow and Improvement of Fracture Limit in Upsetting of Cylinder Using Mildly Wedged Upper Die

Abstract

Upsetting using a mildly wedged upper die was attempted in order to produce a non-axisymmetric part with an oval cross section. The advantage of this upsetting method was that it required no container and caused low forging load. The mild wedge on the upper die promotes dividing material flow in the single direction. The ratio of the major axis to the minor axis of the oval cross section was 1.49 after the compression ratio of 70% in upsetting. The fracture limit of the material was improved by using a mildly wedged upper die with a round top.