Comparative characterisation of Brazilian and Land craft industrial steel rebars: microstructural, wear, and electrochemical corrosion behaviour

This study presents a comparative characterisation of 16 mm Brazilian imported and locally produced Land craft industrial (LCI) reinforcement steel rebars through chemical analysis, ImageJ microstructural evaluation, sliding wear testing, and electrochemical corrosion assessment in 1 M H2SO4. Chemical analysis showed that Brazilian steel exhibited lower levels of detrimental impurities – sulphur (0.014 %), phosphorus (0.0097 %), and copper (0.013 %) – relative to LCI steel (0.056 %, 0.106 %, and 0.253 %, respectively), indicating superior compositional purity. Microstructural analysis revealed a significantly finer grain structure in Brazilian steel (average grain size: 201.94 µm2; Feret diameter: 11.61 µm) compared to coarser-grained LCI steel (1776.30 µm2; 20.71 µm). Sliding wear tests demonstrated that LCI steel lost less mass (0.029 g) than Brazilian steel (0.038 g) under identical sliding conditions, indicating better wear resistance attributed to its coarser, carbide-rich microstructure. Electrochemical evaluation, supported by open-circuit potential measurements, potentiodynamic polarisation curves, and scanning electron microscopy/energy dispersive spectrum (SEM/EDS) post-exposure compositional analysis, revealed distinct corrosion susceptibilities between the two steels in acidic medium: LCI steel showed a higher polarisation resistance (Rp = 23.8 Ohm vs. 6.0 Ohm), a lower corrosion current density (icorr ≈ 128 vs. ≈ 1267 µA/cm2), and a lower corrosion rate (CR ≈ 1.49 vs. ≈ 14.7 mm/y) than Brazilian steel, with compositional and microstructural differences playing a significant role. These results provide a quantitative basis for assessing the corrosion and wear behaviour of both imported and domestically manufactured reinforcement steels under the tested conditions.