Deformation Characteristics of Metallic Preforms

Abstract

Forming technology of sintered preforms is being absorbed rapidly in industrial culture for product development. This paper presents an investigation into the deformation characteristics of iron powder sintered preforms during cold forging using vibrating dies. Experiments are conducted to study the variation of preform density and barrelling profiles with reduction in height along with increasing processing load. The formability of all the preforms were noted when cracks were observed on the equatorial free surface during reduction in height. In order to have uniform deformation interfacial friction was reduced by using the concept of vibrating dies. Accordingly, composite friction law and velocity fields are developed. Using appropriate yield criteria, interfacial friction law, velocity field and the concept of vibrating dies, mathematical model has been developed for processing load and interfacial pressure using energy method approach. The results are presented graphically with processing parameters such as velocity, amplitude of vibration and percentage of deformation.

Results so obtained are quite useful for industrialists and research persons who are interested in technology of sintered preforms.

Keywords- Forming technology, Sintered preform, Vibrating dies, Barrelling profiles, Formability, Interfacial friction.