Theoretical analysis of bimetallic rods extrusion process in double reduction die

The analysis of strain–stress state in bimetallic rods composed from two different metals was done in this work. The analysis was accomplished for two different extrusion ratios in conical die and in double reduction die. The initial material was composed from copper coat and pure aluminium core by explosive method. During the extrusion process of such composites there can be differences between material properties of components that caused significant non-uniform metal flow in deformation zone and appearing defects like chevron cracking or delamination (for composed rods) especially for significant total elongation. It is proposed to use the double reduction die to decrease the values of tensile stresses and maximal stresses between component layers. The results of approximation of mathematical experiment allowed carrying out an equation helpful to define the maximal stress σx max on a boundary between layers of bimetal. FORGE2® commercial software based on the FEM was applied to analysis.