This work presents electrochemical data measured during the corrosion of X70 pipeline steel immersed in aqueous environments containing dissolved H2S. Four different conditions were evaluated: a 3wt% NaCl solution, 3wt% NaCl + 100 ppm H2S, 3wt% NaCl + 650 ppm H2S and a 3 wt% NaCl solution saturated with H2S. The following electrochemical techniques were used in this assessment at stationary conditions: Linear Polarization Resistance (LPR) and Electrochemical Impedance Spectroscopy (EIS). All this information is meant to gain understanding of sour corrosion process in hydrocarbon transport pipelines. Scanning electron microscopy (SEM) images are presented in order to characterize the morphology of the corrosion attack.
Keywords: corrosion, EIS, hydrogen sulfide, LPR, X70 steel.