Influence of Lamellar Direction in Pearlitic Steel Wire on Mechanical Properties and Microstructure Evolution

During cold drawing of pearlitic steel wire, the lamellar structure becomes gradually aligned with the drawing axis, which contributes to the ultra-high strength. A direct simulation about the mechanical behaviors and microstructural evolution of pearlitic lamellae was presented. A representative volume element (RVE) containing one pearlitic colony was established based on the real transmission electron microscope (TEM.) observation. The deformation of pearlitic colony during tension, shear and wire drawing were successfully simulated. The numerical results show that this metallographic texture leads to a strong anisotropy. The colony has higher yielding stress when the lamellar direction is parallel and perpendicular to the tensile direction. The lamellar evolution is strongly dependent on the initial direction and deformation mode. The formation of typical period shear bands is analyzed. In the wire drawing, the pearlitic colony at the sub-surface experiences a complex strain path: rotation, stretching along the die surface, and rotation back.