The evaluation of redundant deformation factors in axi-symmetric bar drawing of austenitic stainless steel

The strain distributions in the cross-section of austenitic 304 stainless steel bars, caused by axi-symmetric drawing under various conditions, were obtained using finite element method (FEM) simulations. Also, the effective tensile stress-strain curves of the initially annealed and of the drawn bars were determined. The FEM analysis and the tensile testing allowed the evaluation of redundant deformation factors for each drawing condition. The former involved an averaging of the strain distribution over the cross-section of the drawn bars, whereas the latter was based on the superposition of the stress-strain curves for the annealed and drawn material. The results from the FEM analysis are higher than those from the superposition technique, when Delta values are above 2. This is associated with the differing strain averaging procedures in the two methods. The superposition method reflects the hardening characteristics of the material and its consequent final mechanical properties. On the other hand, FEM simulations depend on these hardening characteristics only in as much the FEM codes are initially fed with tensile stress-strain curves for the material. (C) 2002 Elsevier Science B.V. All rights reserved.