An analytical approach to the stress field in the extrusion of bimetallic tubes

this paper an analytical solution for the extrusion of bimetallic tubes is deduced by assuming an axially-symmetric radial flow through a conical die. Different extrusion conditions and different material combinations are considered to assess the stress levels at critical zones. Solutions for the two possible locations of the harder material (acting as an inner or outer lining) are presented. The analysis highlights the effects on the extrusion process of a number of parameters, such as the yield stress ratio between the materials, the die angle and the volume fraction of the harder component. A ductile failure factor is introduced and evaluated for all the cases contemplated in the paper.