Research on Precision Die Forging Utilizing Divided Flow : First report, Theoretical analysis of processes utilizing flow relief-axis and relief-hole

Abstract

In the conventional closed die forging, working loads increase rapidly at the stroke end and a complete filling up of materials into die cavity is impossible. A new precision forging process is proposed in this research. A flow relief-hole is prepared in the middle of a die or a specimen to reduce working loads by causing an inward material flow by forming a relief-axis or by shrinking the diameter of the relief-hole in this process. The reduction of working loads enlarges the depression and causes a preferable outward material flow to occur, which contributes to the complete filling up. In this report, the filling up behavior in a barrelled disk specimen will be analyzed theoretically by the upper bound theory and possibility of decreasing working loads will be made clear.