Abstract The electrochemical and stress corrosion cracking behavior of two pipeline steels commonly used in China were studied in a range of carbonate/bicarbonate solutions using potentiodynamic polarization techniques and the SCC tests. The influences of concentrations of carbonate, bicarbonate, oxygen and other compounds in solutions on their polarization characteristics as well as passivation behavior of pipeline steels were investigated. The SCC tests were conducted with bended tensile specimens and high concentration carbonate/bicarbonate solutions at 75°C. The sensitivity potentials were determined by fast and slow sweep rate curves and current-time curves. The typical corrosion stripes were observed on steel specimens after prolonged exposure to the solution used for the SCC tests at the sensitivity potentials that were believed as a premonitory of SCC. Two different surface films on the steels were found after SCC tests depending on the control potentials. Their morphology and composition were also analyzed using SEM and X-ray energy dispersion.