In situ corrosion characterization of simulated weld heat affected zone on API X80 pipeline steel

Subject to Gleeble processing, microstructures of weld heat affected zone were simulated in X80 steel. Corrosion behavior of the simulated specimen with a microstructure gradient was studied by polarization, local electrochemical impedance spectroscopy and scanning vibrating electrode technique. Microstructure of granular bainite mixed with ferrite (region B) showed the highest charge transfer resistance and the most positive current density value. Acicular ferrite base metal displayed the lowest charge transfer resistance and the most negative current density. Both the positive and negative peak current densities increased at the first few hours of immersion followed by a decrease.