Planteamiento y validación de una metodología de análisis de la fisuración inducida por ambiente basada en la teoría de las distancias críticas

Résumé

Environmentally Assisted Cracking (EAC) is a phenomenon that leads to catastrophic and unexpected failures. It is necessary to understand the behaviour of materials in aggressive environments in order to ensure the integrity of components and structures. This work provides a detailed analysis of the behaviour of two steels, used in the energy industry, and proposes and validates a methodology based on the Theory of Critical Distances. This methodology provides predictions of the crack propagation threshold cracked and notched components with great accuracy. The proposed methodology has been validated according to a solid experimental program that gathers slow strain rate tests in C(T) specimens with five notch radii, from 0.00 mm (crack-like defect) up to 2.00 mm, two different applied current densities (1 and 5 mA/cm2), which encourage the hydrogen adsorption into the material, and two very slow test rates (6·10-8 and 6·10-9 m/s). Tensile tests and hydrogen content have also been carried out under aggressive conditions. The failure mechanisms in the materials have also been analysed through the SEM. The main conclusion is that the proposed methodology predicts in an accurate way the behaviour of the materials studied under the aggressive environmental conditions analysed.