Influence of pre-torsion deformation on microstructures and properties of cold drawing pearlitic steel wires

The influences of pre-torsion deformation on microstructures, tensile strength and microhardness of cold drawing pearlitic steel wires have been investigated in this study by twisting the wires to different number of revolutions. The results indicated that the tensile strength is very sensitive to torsion deformation and reduced distinctly after pre-torsion. Microhardness in the center layer and surface layer displayed different evoluting process with increasing number of the pre-torsion revolutions. Boundary strengthening reduced by fragmentation of cementite lamellae and work hardening enhanced by strain gradient induced by the pre-torsion were discussed to reveal the changes of the tensile strength and microhardness.