Stress corrosion cracking mechanism of prestressing steels in bicarbonate solutions

Abstract

This paper presents the valuation of a new method of controlled localized attack used to study the susceptibility of the high strength steels resistance to Stress Corrosion Cracking (SCC). The innovation of this method resides in raising the study of the growth of the fissure combining electrochemical and mechanical parameters. The method consists of several stages: constant load and controlled potential test in the media, mechanical test in air and fractographic study. It allows calculating the crack propagation rate and the fracture toughness in the same test, where the crack is not produced by fatigue. First of all, the way of concentration of the damage has been selected. Before, a few tests were carried out to know the influence of the applied potential on the crack propagation. Finally, it has been possible to apply the Surface Mobility Mechanism (SMM) in order to approach the identification of the SCC mechanism operating.