Influence of barreling in deformation and densification behaviour of sintered powder forged preforms

The present research establishes a relationship between density and combined axial and hoop strain experienced by the powder metallurgy (P/M) preforms during processing and an experimental investigation on the cold upsetting of a Cu-7%Al-1.8%Si preform is studied in the present work. Preforms with three different aspect ratios (height-to-diameter ratio), namely, 0.4, 0.6 and 1 were prepared by primary P/M operations followed by furnace cooled. Further these preforms were subjected to secondary operations such as cold upsetting under dry friction condition. The calculated barrel radius conformed to the experimentally measured barrel radius and a linear behaviour was observed between the measured and calculated radius of curvature of the barrel. Also, a relationship is established between barrelling and density and other influencing physical parameter such as the stress ratios, namely, (σ_z⁄σ_m ),(σ_θ⁄σ_m ) and(σ_θ⁄σ_eff ), which were determined using dimensional output and density measurements