Effect of cold-drawn induced anisotropy on the failure of high strength eutectoid and duplex steel wires

• Comparative analysis of the failure behaviour of damaged duplex and eutectoid wires.
• Fracture anisotropy governs the failure mechanism of both type of wires.
• Damaged eutectoid wire fails under combined tension and bending plastic collapse.
• Damaged duplex steel wire fails by plastic collapse in tension.

The paper presents a comparative analysis of the failure behaviour of duplex and eutectoid cold-drawn wires carried out from the experiments performed to produce the failure of the wires when damaged. The failure mechanisms at micro and macro scales are described according to relevant optical and scanning electron microscopy observations, and modelled analytically on the basis of elementary theory of mechanical behaviour. The microstructure orientation is the determinant factor of the fracture anisotropy, which governs the failure mechanism of both duplex, and eutectoid cracked wires. The damage tolerance exhibited by the duplex cracked wires agrees with the load upper bound given by the plastic collapse of the resistant ligament in simple tension, whereas the damage tolerance exhibited by the eutectoid wires deviated from this upper bound, with failure occurring under combined tension and bending plastic collapse.