The effect of microstructure and texture evolution on mechanical properties of low-carbon steel processed by the continuous hybrid process

In this paper, the continuous hybrid process is newly designed and applied for producing grain-refined long and large cross-section wires of low-carbon steel at high speed at room temperature. The initial specimen, with a diameter of 13 mm, continuously passes through the rolls, equal channel angular pressing (ECAP) dies, and wire-drawing dies in sequence during the process. The specimens deformed by the continuous hybrid process without and with the wire-drawing dies were obtained to investigate the role in the deformation separately. Their microstructures, textures, and mechanical properties were investigated by optical microscopy (OM), electron backscattering diffraction (EBSD), X-ray diffraction (XRD), tension, and Vickers micro-hardness tests and were compared with those for the case processed by the conventional wire-drawing process. According to the present investigation, the continuous hybrid process can more efficiently manufacture fine-grained wires with a strong shear texture in a continuous way than the conventional wire-drawing process can. In addition, the ultimate tensile strength value of the specimen processed by the continuous hybrid process was 23.9% higher, although the elongation was slightly lower than the one produced by the conventional wire-drawing process. The plastic deformation was mainly imposed by the ECAP dies, and the wire-drawing dies improve the dimensional accuracy and increase the local strain homogeneity in the continuous hybrid process. It is demonstrated that the continuous hybrid process might be beneficial in commercializing a continuous application of the severe plastic deformation process for producing grain-refined wires for industrial applications. (C) 2013 Elsevier B.V. All rights reserved.