Enhancing the formability of FeSi6.5 steel by the anodic polarization

The effect of anodic polarization on the plastic deformation behavior and formability of FeSi6.5 steel at room temperature was experimentally investigated through uniaxial tensile and drawing of wire specimen in sulfuric acid solution with current densities of 0–40 mA/cm². The formability of the FeSi6.5 steel was significantly improved after the anodic polarization. The plastic elongation of the specimen as an anode in the electrochemical environment was 4.4%–7%, but 2.7% in the air. The drawing force under the anodic polarization decreased by 12.5%–26% compared to that in deionized water. The softening is mainly attributed to the relief in work hardening caused by surface atomic dissolution. The work hardening mechanism of the FeSi6.5 steel wires under anodic polarization condition was analyzed using Hollomon equation and Voce relation combined with the Kocks-Mecking approach. These data support the view that the surface atom dissolution facilitates dislocation slip. FeSi6.5 steel wires were obtained using electrochemical cold drawing and presented a smooth surface and good ductility without crack after five-pass drawing with a total cross-section area reduction of 88%. The drawing with the assistance of anodic polarization is a promising technology for processing hard and brittle metal materials.