Low-carbon micro-alloyed oil and gas pipeline steel: effect of different heat treatment processes on the electrochemical corrosion behavior

Purpose This study aims to investigate the impact of two distinct heat treatment processes on the electrochemical corrosion behavior of low-carbon micro-alloyed steel. Design/methodology/approach The first process transforms the banded ferrite–pearlite microstructure into a quasi-polygonal ferrite structure with sporadic austenite at grain boundaries. The second process uses quenching and partitioning to develop a bainitic microstructure containing interlath and sporadic blocks of retained austenite. Electrochemical analyses, including potentiodynamic polarization and electrochemical impedance spectroscopy, were conducted to assess corrosion resistance. Findings Results indicate that both heat treatment procedure improves the corrosion resistance of the micro-alloyed steel with the quasi-polygonal ferrite structure exhibiting superior corrosion resistance compared to the bainitic structure. The presence of retained austenite in both microstructures influences corrosion behavior, with its distribution and morphology playing a critical role. Originality/value These findings provide valuable insights into optimizing heat treatment processes to enhance the corrosion resistance of low-carbon micro-alloyed steels for industrial applications.