Corrosion failure analysis of L485 natural gas pipeline in CO2 environment

•The work studies corrosion failure analysis of L485 pipeline in CO2 environment.•The corrosion scale mainly consists of FeCO3.•The actual corrosion rate is at the range of 1.413–1.978mm/a.•The Mn content of L485 steel exceeds the standard compared with API Spec 5L.•Corrosion undergoes the bare metal, scale-covered, reaction destruction period.