Corrosion behaviour of low-alloy steel containing 1% Cr ( 1Cr) with normalized ( ferritic- pearlitic ) and quenched-and-tempered ( tempered martensitic ) microstructures was investigated in CO2 environments at 60℃.As compared to carbon steel N80,the severe localized corrosion disappears for low-alloy steel 1Cr due to the occurrence of the compact and self-repairable Cr-rich scale.For low-alloy steel,the corrosion resistance of 1Cr with ferritic-pearlitic microstructure is better than that of tempered martensitic microstructure.A severe corrosion scale spallation is obviously observed on the surface of quenched-and-tempered 1Cr,however,only slight scale spallation was observed for normalized ICr.