Modelling and measurements of mechanical behaviour in multi-pass drawing process

The paper focuses on the theoretical considerations as well as experimental investigations concerning cylindrical bar drawing processes with different drawing schedules. The single- and multi-pass drawing technologies were analysed. The finite element method calculations resulted in obtaining the distributions of strain rate tensor components, effective strain rate, effective strain and temperature. The deformation of the grid of coordinates was also determined experimentally in order to describe the strain state in the die deformation zone. The experiments included the measurements of strains and mechanical properties distributions on the cross sections of drawn products. The obtained results describing theoretical distributions of effective strain were compared with the experimental data. The changes of mechanical properties of final products drawn in single- and;multi pass technologies, applying various drawing velocities, were analysed. As a result of investigations which have been carried out the answer was obtained to the question: whether and to what extent the properties of the products obtained in multi-stage technologies of deformation are connected with the parameters used in individual single operations and what conditions have to be fulfilled in order to obtain the final product of proper quality. The materials being investigated were stainless steel and copper. (C) 1998 Elsevier Science S.A. All rights reserved.