COMBINED ROD AND TUBE EXTRUSION - NUMERICAL-SOLUTION OF AXISYMMETRICAL SLIP-LINE FIELDS AND ASSOCIATED VELOCITY-FIELDS

Numerical method of construction of axi-symmetric slip-line fields and associated velocity fields in the form of computographic plots of axi al and radial velocity components, earlier given by the authors for ro d extrusion and tube extrusion, was extended to the solution of two ty pes of combined rod and tube extrusions: (i) where the rod and tube ar e extruded in opposite direction to each other and (ii) where, both th e 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 estim ated, using simple upper bound analysis and the experimental work of t he authors. Copyright (C) 1996 Elsevier Science Ltd.