ASCERTAINMENT OF THE CHANGE OF THE DUCTILITY IN CORRODED STEEL SPECIMENS BY EXPERIMENT

The studies of the ductility of the materials date back to ancient times. The basic values of the stress-strain diagram, which determines the groups in the main zones - the elastic zone, the yield zone, the strengthening zone and the fracture zone, are known. There are main construction steel elements always where corrosion is at an advanced stage. The corrosion of construction steel is an inevitable process. The negative consequences that indicate the corrosion of the steel elements have been partially established and opportunities for solving them should be sought. We conducted an experiment to determine how the ductility and main values of the stress-strain curve of corroded steel samples changed. We used S355JR steel and applied a galvanostatic electrochemical accelerated corrosion method. After that, we performed a tensile test of the samples, we took the values from the stress-strain diagrams and we calculated how the basic stress-strain values and the corresponding ductility changed. We used the stochastic method to process the results. We have come to the conclusion that corrosion affects the basic values, the ductility and the structural change of the material and when (and if) it is elastic-plastic, according to the stress-strain diagram, it is transformed into brittle material.