Combined rod and tube extrusion: Numerical solution of axi-symmetric slip-line fields and associated velocity fields

Abstract

Numerical method of construction of axi-symmetric slip-line fields and associated velocity fields in the form of computographic plots of axial and radial velocity components, earlier given by the authors for rod extrusion and tube extrusion, was extended to the solution of two types of combined rod and tube extrusions: (i) where the rod and tube are extruded in opposite direction to each other and (ii) where, both the rod and tube move in the same axial direction as the punch movement during the extrusion process. Computographic plots of slip-line fields and associated velocity fields in the ( r, z) plane are given and the deficiencies noticed in the solutions are highlighted. The results of specific punch pressures are observed to compare well with those estimated, using simple upper bound analysis and the experimental work of the authors.