Phenomenon of barrelling in aluminium solid cylinders during cold upset-forming

Experiments were carried out to generate data on the upset forging of solid cylinders of annealed aluminium. The curvatures of the barrelled aluminium cylinders measured physically were found to conform closely with the values calculated using the experimental data. The calculations were made on the assumption that the curvature of the barrel followed the geometry of a circular are. It was further found that the measured radius of curvature of the barrel exhibited a straight-line relationship with the new geometrical shape-factor, irrespective of the aspect ratios of the cylinders. Further empirical relationships were found to exist between the measured radius of curvature of the barrel and other variables such as the hydrostatic stress and the stress-ratio parameter. (C) 1997 Elsevier Science S.A.