Cold Radial Extrusion of a Gear-Like Element with Flow Relief Opening

Abstract

When divided material flow is enabled during extrusion process, the required forming load is lower compared to a conventional process. The reduction of forming load leads to higher quality of extruded part and longer tool life. One way to achieve divided material flow is the application of a relief opening, either in the billet or in the tool. In this paper, theoretical solution based upon the Upper bound theorem was used to determine the forming load for radial extrusion of a gear-like element with straight parallel flank profile. Two possible positions of relief openings were analysed - in the centre of the billet and in the centre of the punch. Theoretical solution was compared to experimental results. Material of billets was Al 99,5. Comparison between theoretical and experimental values of the forming load showed fairly good agreement. Further development of the proposed theoretical solution should lead to better process description and more accurate value of the forming load.

Keywords

• extrusion
• gear-like element
• relief opening
• upper bound