Influencia de las tensiones residuales en la corrosión bajo tensión de los aceros de pretensado

Influence of residual stresses on the stress corrosion of prestessed concrete wires

The aim of this paper is to show the influence of residual stresses, due to cold-drawing, on the stress corrosion susceptibility of pearlitic wires used for prestressing concrete. Surface residual stresses were measured by X-ray diffraction and a 3D finite element model was used to simulate the drawing process. Stress corrosion susceptibility was evaluated through rupture times in NH4SCN tests. A very good correlation was found between rupture times in NH4SCN tests and residual stresses at the surface of the wires. The presence of residual stresses may help in explaining the scatter in times to rupture, the disappearance of a stress threshold, the differences in times to rupture of steel wires with the same microstructure, surface quality and mechanical properties, or the saturation in rupture time above certain values of the testing load.