Anisotropía de la fragilización por hidrógeno en acero perlítico trefiladoRecordando el “Cristo muerto” de Andrea Mantegna

Abstract

Progressive cold drawing in eutectoid steel produces a preferential orientation of pearlitic colonies and ferrite/cementite lamellae, thus inducing strength anisotropy in the steel and mixed mode propagation. While in the hot rolled steel (not cold drawn) the pearlitic microstructure is randomly oriented and the crack progresses in hydrogen by breaking the ferrite/cementite lamellae, in heavily drawn steels the pearlitic microstructure is fully oriented and the predominant mechanism of hydrogen assisted cracking is the delamination (or decohesion) at the ferrite/cementite interface. A link is established between the oriented microstructure of the heavily cold drawn pearlitic steels wires and their anisotropy of hydrogen embrittlement behaviour associated with hydrogen assisted cracking path deflection with angle close to 90º, thereby resembling the Mantegna’s “Dead Christ”.