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

• Published in: Corrosion science Vol. 85; pp. 401 - 410
• Main Authors: Wang, L.W., Liu, Z.Y., Cui, Z.Y., Du, C.W., Wang, X.H., Li, X.G.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2014; Elsevier
• Subjects: A. Steel; Applied sciences; B. Polarization; B. SEM; C. Acid corrosion; C. Welding; Corrosion; Corrosion environments; Exact sciences and technology; Joining, thermal cutting: metallurgical aspects; Metals. Metallurgy; Welding; B. SEM; A. Steel; C. Welding; C. Acid corrosion; B. Polarization; Scanning electron microscopy; Acid corrosion; Welding; In situ; Pipeline; Oil industry; Welded joint; Microalloyed steel; Carbon steel; Heat affected zone; Application
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2014.04.053

•Heat affected zone was simulated by Gleeble thermomechanical treatment.•Granular bainite mixed with ferrite has the highest anodic current density.•Acicular ferrite has higher cathodic current density than other microstructures.•Both the anodic and cathodic peak current densities increased followed by a decrease. 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.