Influence of Flow Stress and Friction Upon Metal Flow in Upset Forging of Rings and Cylinders

Abstract

An upper-bound velocity field that considers bulging has been applied to cylinder and ring upsetting. Computer programs have been developed to (a) determine strain, strain rate, velocity, and flow-stress distributions, and (b) predict load and bulge profile at various reductions by simulating the upsetting process. The calibration curve for a 6:3:2 ring, the load-displacement curves for ring and cylinder upsetting, and flow stress from the ring test have been predicted. The experimental results, with annealed 1100 Aluminum samples, agree well with theory at the lower and practical range of friction, but they show some disagreement at high friction.