Studies on flow behavior of aluminum using vision system during cold upsetting

Cylindrical specimens of Electrical Conductivity grade aluminum were upset between flat platens to study the metal flow at room temperature. Platen-specimen-interface lubrication and specimen aspect ratio (height/diameter) were studied as process parameters. A vision system using PC-based video recording with a CCD (charge coupled device) camera was used to study the predrawn grid deformation at the midplane of the specimen and corresponding flow behavior. The forming process has been modeled and analyzed using the finite element software ANSYS. Lubrication minimized barreling of the lateral-free surface. Barreling decreased with increased aspect ratio. Microhardness studies reveal nonuniform deformation within the specimen. This effect was pronounced with high friction and low aspect ratio. [PUBLICATION ABSTRACT]