Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Investigations concerning the electrochemical corrosion behaviour of low carbon (LC) and ultra-low carbon (ULC) steels are relatively scarce and limited. The present study aims to compare electrochemical impedance parameters and potentiodynamic polarization curves of an LC steel and an ULC Ti-interstitial free (IF) steel evidencing the effects of carbon content and pearlite fraction on the electrochemical corrosion behaviour. Corrosion tests were carried out in a 0.5 M NaCl solution at 25 degrees C with a pH range between 6.5 and 6.8. It was found that the IF steel sample presents an electrochemical corrosion resistance, which is slightly higher than that of the LC steel sample.615407411Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAEPEX-UNICAMPConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)