Microstructure-based modelling of localized anodic dissolution in pearlitic steels

This paper analyzes the process of stress corrosion cracking by localized anodic dissolution in pearlitic steels which are increasingly cold drawn in the course of manufacturing to produce prestressing steel wires used in prestressed concrete. A microstructure-based modelling of the environmentally-assisted fracture phenomenon is proposed to rationalize the results for different degrees of drawing. The model is based on the preferential dissolution of ferrite and on the progressive microstructural orientation by cold drawing (manufacturing technique) of the two basic microstructural levels of the pearlite colonies and pearlitic lamellar microstructure, which could influence the magnitude of crack tip blunting and the blunting mode itself by favouring cornered crack tip shape (by preferential dissolution) over smooth crack tip profile, thus increasing the effective crack tip radius (blunting effect).