Performing a numerical analysis in the nonlinear range requires entering appropriate input data for the material. For this purpose, the actual stress-strain characteristic is used for the finite element calculation. In order to establish the actual stress-strain curve, a simple tensile test of a steel specimen was performed. The stress-strain curve obtained from the numerical analysis was compared with the tensile test result. Additionally, the work compares the use of three material models for the screw connection of cold-bent elements on the basis of the numerical analysis performed. One of the models used for the calculations was based on the characteristics of a bilinear material with gain. The remaining ones were defined on the basis of the tensile test curve and the real curve obtained from transformations.