Some aspects on barrelling in aluminium solid cylinders during cold upset forging using a die with constraints

Experiments were carried out to generate data on cold upset forging of solid cylinders of annealed aluminium using a die with constraints. During the experiments, two barrels namely top barrel and bottom barrel were observed. The radius of curvatures of both barrels measured experimentally was found to conform one to one with the calculated values using experimental data. The calculations were made on the assumption that the curvature of the barrels were in the form of a circular arc. It was further found that the measured radius of curvature of both barrels exhibited a straight line relationship against the new geometrical shape factor, irrespective of the aspect ratio of the cylinders. Further empirical relationship was established between the measured radius of curvature of the barrels and parameters namely the stress ratio factor and the hydrostatic stress.