Anisotropic fracture behaviour of cold drawn steel: a materials science approach

In this paper the fracture performance of axisymmetric notched samples taken from pearlitic steels with different levels of cold drawing is studied. To this end, a real manufacture chain was stopped in the course of the process, and samples of all intermediate stages were extracted. Thus the drawing intensity or straining level (represented by the yield strength) is treated as the fundamental variable to elucidate the consequences of the manufacturing route on the posterior fracture performance of the material. A materials science approach to the phenomenon is proposed, so that the strongly anisotropic fracture behaviour of the steels with high level of strain hardening (which exhibit a 90° step in the fracture surface) is rationalized on the basis of the markedly oriented pearlitic microstructure of the drawn steels which influences the operative micromechanism of fracture in this case.