Structural integrity of progressively cold-drawn pearlitic steels: From Raffaello Sanzio to Vincent van Gogh

This papers deals with fracture behavior and structural integrity of progressively cold-drawn pearlitic steels on the basis of their microstructural evolution during manufacturing by multi-step cold drawing. It is seen that the manufacture technique by progressive cold drawing in several steps produces a microstructural evolution in the form of progressive slenderizing and orientation (in the wire axis or cold drawing direction) of the pearlitic colonies (first microstructural level), as well as increasing orientation and densification of the ferrite/cementite lamellae (second microstructural level) linked with a decrease of pearlite (ferrite/cementite) interlamellar spacing. Thus the microstructure of the cold-drawn pearlitic steel wires becomes progressively oriented as the cold-drawing degree increases and this microstructural fact influences their macroscopic behavior by inducing anisotropic fracture and crack path deflection. Therefore, this paper offers a micro- and macro-approach to the fracture and structural integrity of cold-drawn pearlitic steels, introducing the new concept of microstructural integrity.