Phenomenon of barrelling in square billets of aluminium during cold upset forging

Experiments were carried out to generate data on the upset forging of square billets of annealed aluminium. The measured curvatures of the barrelled aluminium square billets were found to conform with calculated values using experimental data. The calculations were made on the assumption that the curvature of the barrel followed the geometry of a circular arc. 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 square billets. Further empirical relationships were found to exist between the measured radius of curvature of the barrel and independently with other variables like hydrostatic stress and stress ratio parameter.