Cold Drawn Eutectoid Pearlitic Steel Wires as High Performance Materials in Structural Engineering

摘要

This paper reviews the fracture performance in air and aggressive environment (stress corrosion cracking) of eutectoid prestressing steel wires with different levels of cold drawing. In air environment, a microme-chanical model of fracture is proposed to rationalize the results on the basis of the microstructure of the steels after drawing and the model of Miller & Smith of fracture of pearlitic microstructure by shear cracking of the ce-mentite lamellae. In hydrogen assisted cracking (HAC), a microstructure-based model is proposed on the basis of the Miller & Smith model and the mechanism of hydrogen enhanced decohesion or, more properly, hydrogen enhanced delamination (or debonding) between similar microstructural units (colonies or lamellae). In aggressive environments promoting localised anodic dissolution (LAD), the micromechanical model is based on the phenomenon of crack tip blunting and the preferential dissolution of ferrite which favours cornered crack tip shape over smooth crack tip profile.