An upper bound solution of forging load in cold radial forging process of rectangular cross-section billet

Abstract

Investigation in the radial forging process for rectangular cross-section billet is scarce. In this paper, a kind of radial forging method for rectangular cross-section billet is studied. For simplicity, a rectangular cross-section billet, being forged in one hammer stroke at the middle part by two pairs of hammers, is considered. Based on a kinematically admissible velocity field, a three-dimensional model by the upper bound method (UBM) is proposed to predict the forging load in the radial forging process. Because of the non-steady flow of material in one stroke of the forging process, the forging process is divided into finite steps so that each step can be assumed as steady flow. The accuracy of the UBM model is verified by the results acquired through radial forging experiments and that of the three-dimensional finite element simulation. Then, the influences of various process parameters on the forging load and longitudinal flow of material are discussed.