Research On Texture Intheritance Of Cold Drawn Steel Wire And The Effect On Deformation

In this paper, a systematic research was conducted on the microstructure and texture evolution pattern of cold drawn pearlitic steel wire, as well as the texture inheritance phenomenon and its influence to the deformation after wise, by using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), X-ray Diffraction analysis method (XRD), Electron Backscattered Diffraction (EBSD) system and related mechanical properties testing methods. The evolution of dislocation configuration in deformation was studied. The effect of ferrite crystal orientation on dislocation configuration was also discussed.The tensile strength of steel wires increases as the deformation strain increases. The equiaxed pearlite becomes fibrosis and the lamellar spacing decreases as the strain increases. The lamellar which had a large angle from the drawing axis will occur kink bending deformation. The intensity of<110> fiber texture in the ferrite increases with the deformation strain.The texture inheritance phenomenon after austenitizing treatment to cold drawn pearlitic steel wire was studied. The results show that:the ferrite<110> texture can be partly inherent after austenitizing treatment. The intensity of the inherent texture increases with the increase of the original strain of the steel wire, decreases with the increase of austenitizing temperature and the prolongation of austenizing holding time.The effect of inherent texture on deformation was studied. The results show that:the steel wires with inherent texture have larger work hardening rate than steel wires without inherent texture. The intensity of texture in steel wires with inherent texture is always higher than that of steel wires without inherent texture during drawing process. The amount of shear deformation bands in steel wires with inherent texture decreases 27% than the steel wires without inherent texture. The shear deformation band has weaker microstructure mechanical properties than the straight lamellar. Thus, the shear deformation band is not conducive to the increase of strength of steel wire.The dislocation configuration in pearlite steel wires during deformation was studied. The results show that:1) there are a number of dislocations in non-deformed pearlite.2) As the strain increases, the ferrite dislocation slip changed from single slip stage to multiple slip stage. High density dislocations area forms in specimen with large strain.3) In the steel wires with small deformation strain, dislocation lines are perpendicular to the lamellae which has a <110> orientated lamellar ferrite, and the dislocation lines have an angle to the lamella in non <110> orientated lamellar ferrite. With the increasing of deformation strain, multiple slip of dislocations will first happen in the non<110> orientated lamellar ferrite produce more, and then took the lead in the formation of high-density dislocations area which have adverse effect on the mechanical properties of steel wires.