Effect of friction on barrelling in square billets of aluminium during cold upset forging

This work deals with the generation of data on cold upset forging of square billets of annealed aluminium under different frictional conditions. Three different aspect ratios and constant load levels were considered for the above said upsetting experiment. The calculations were made on the assumption that the curvature of the barrel followed the geometry of circular arc. The measured radius of curvature of the bulge was found to confirm with calculated values obtained using experimental data. Relationships were established between the experimentally derived values of friction factors for different lubricants from standard compression tests and bulge parameters such as new hoop strain, geometrical shape factor and the stress ratio parameter and hydrostatic stress.