Galvanic corrosion of electric resistance welded X52 steel in CO2-containing solution

Purpose – This paper aims to report an experimental investigation of the galvanic corrosion that occurs between the base metal and the welds in X52 carbon steel petroleum pipelines when exposed in carbon dioxide (CO2)-containing saltwater at pH 4 at room temperature. The pipeline was fabricated by electric resistance welding (ERW). Design/methodology/approach – The experimental setup was a closed glass cell equipped with a silver/silver chloride (Ag/AgCl) reference electrode, two working electrodes (the weld metal and the parent steel specimens) and a gas bubbler. The corrosion potential and polarization resistance of the base metal and the weld were determined using electrochemical testing methods: potentiodynamic polarization scans and linear polarization resistance measurement. The galvanic currents of the base metal when coupled to the weld metal were measured using zero resistance ammetry. Findings – The weld metal was the anode of the couple for a very short time at the beginning of the experiment a...