Deformation behavior of Al–4Cu–2Mg alloy during cold upset forging

Upsetting of cylinders is a standard test which determines the ability of material to be forged either in cold or warm worked condition without cracking. In the present work, cylindrical specimens of aluminum–4% copper–2% magnesium alloy are upset between flat platens to study the metal flow at room temperature. Lubrication at the interface of the die/work piece and the specimen aspect ratio (H0/D0) are studied as process parameters. Lubrication minimized the barreling of lateral free surface. Microstructural studies reveal the non-uniform deformation within the specimen. This effect is pronounced with high friction and low aspect ratio. Machine Vision system using PC-based video recording with CCD camera is used to study the pre-drawn square grid deformation at the equatorial plane of the specimen. The system is used to measure the axial and circumferential strain components during deformation. Finite element analysis of cold upsetting process is carried out in both dry and lubricated conditions with aspect ratios of 1.0 and 1.5. Rigid-flexible contact analysis is performed for the forming process. When the stress values obtained from finite element analysis are compared to the measurement of grids using the Machine Vision system it is found that they are in close proximity.