A new proposal for defining the ductility of concrete-reinforcement steels by means of a single parameter

Modern testing machinery currently enables the highly-accurate and complete measurement of the trend of the stress-strain diagram for a given type of steel, particularly with respect to the evaluation of elongation at the start of the strain-hardening phase, (E-sh), and. under maximum load, i.e. uniform elongation (E-u). Associating these values with those of the yield strength, f(y), and ultimate tensile strength, f(t), enables an evaluation of the area coming within these four parameters (that we shall call A*(nom)), which unequivocally defines the deformation work of the material during the strain-hardening phase. In our opinion, this area summarizes the concept of ductility and consequently provides a further parameter for qualifying steels in terms of their deformative features. This proposal is applied to B500 steels, illustrating the operational methods involved and enabling a comparison of the results obtained using the standard criteria with those achieved by measuring the area (A*(nom)).