THOMAS Piotr Kielce University of Technology

Combined extrusion can be described as simultaneous forward extrusion of the cylindrical part and backward extrusion of the sleeved part of the stamping. The paper presents results of the computer simulation of the combined extrusion for different values of the relative deformations in the ranges of stress forces and unitary stresses. Obtained results were verified experimen-tally. The paper presents the also simulation and experimental research results of backward and forward extrusion for the same relative deformations. It has been proved that in the case of combined extrusion stress forces are smaller than in the case of shaping of stampings of this type by two operations, when the first operation is the extrusion of the cylindrical part of the stamping and the second one is the backward extrusion of the sleeved part. Application of combined extrusion decreases labouriousness of the production of stampings of this type, tool costs and due to decreased stress forces increases their durability.