<p>Eutectoid steel wire rods are widely employed in the automotive and construction sectors, where service life and mechanical performance are strongly governed by microstructural features. In this work, controlled thermal cycling was applied to modify the microstructure of the wire rods. Distinct fractions of spheroidized cementite were obtained through repeated heating and cooling sequences (4, 6, 8, and 10&#xa0;cycles). Each cycle involved brief austenitization at ~ 830°C followed by cooling to ~ 700°C with short holding periods. The purpose of spheroidization was to enhance ductility and toughness while retaining adequate strength. Mechanical behavior was assessed via tensile testing at a strain rate of 0.005&#xa0;s⁻¹, and corrosion response was examined using potentiodynamic polarization under conditions representative of industrial environments. The results show that increasing spheroidization improves tensile ductility while reducing corrosion resistance. The decline in corrosion resistance was attributed to increased ferrite exposure, which acted anodically relative to spheroidized cementite cathodes, thereby accelerating galvanic attack. Overall, ductility rose with increasing cycles, whereas strength decreased. Tensile deformation revealed a two-stage transition from elastic to plastic flow. Microstructural changes were characterized using scanning electron microscopy, and dilatometry provided further insight into phase transformations during cyclic heat treatment.</p>