Preparation of rivet shape head from sintered aluminum specimen at varying strain rates by cold forging

Abstract

Nowadays industries are taking strength enhancement and weight reduction its main criteria’s for selecting any material. This paper analyses the process of slow speed, shape heading forging where the initially circular porous aluminum powder specimen fixed by one of its ends, is headed into a circular shaped head rivet by appropriate yield criterion, friction law and using an upper bound approach. For the relative average forging pressure of the specimen for different strain intensity, a mathematical model was formulated. The specimens were prepared and subjected to upset rivet head forging process for strain rates of 1.5, 50, 100 and 150 mm/min under lubricated end conditions. Parametric analysis showing deviation of the average forging pressure with percentage reduction in height during rivet head forging process was done graphically. Theoretically and experimentally obtained values of forging load versus percentage reduction in height of the specimen during the process were plotted and a satisfactory equivalence was perceived. Effects of strain rate on load forging during the process of forming the circular rivet head versus percentage height reduction were analyzed and critically addressed.