The manufacturing process by cold drawing in pearlitic steels produces important microstructural changes at the two levels of pearlitic colonies and lamellae which become progressively oriented in a direction quasi-parallel to the wire axis or cold drawing direction.The behaviour of the notched geometries of high strength pearlitic steel with different degrees of cold drawing depends on both the yield strength and the notch geometry, the former influencing the size of the curve and the latter controlling the shape of it and the kind of fracture (brittle/ductile) behaviour.The fractographic appearance of the broken surfaces shows that the fracture surface becomes more stepped as the degree of cold drawing increases, it being macroscopically flat in slightly drawn steels and very irregular (containing 90 deg steps) in heavily drawn steels.The very high triaxiality and constraint generated by the shallowest and deepest notch geometry produces a macroscopically brittle behaviour and increases the critical stress very well above the yield strength and the ultimate tensile strength of the prestressing steel.From the fractographic viewpoint, there is a materials science relationship between the microstructural orientation (in the wire axis direction) produced by cold drawing and the appearance of the fracture profile which becomes more stepped as the degree of cold drawing increases.
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