Corrosion of new 13Cr martensitic stainless steel OCTG in severe CO{sub 2} environment

Resistance of a new 13Cr martensitic stainless steel (0.025C-13Cr-4Ni-1Mo) to CO{sub 2} corrosion and to SSC was investigated and the application limit in oil and gas environments was clarified. The new 13Cr steel had a better CO{sub 2} corrosion resistance than the conventional 13Cr (0.2C-13Cr) due to Ni addition. The new 13Cr steel can be used at a CO{sub 2} pressure of up to 5mpa at 150 C, compared with that of only below 0.5MPa for the conventional 13Cr. The new 13Cr steel had also better SSC resistance. The new 13Cr steel did not crack in the U-bend test in the 5%NaCl solution saturated with 0.003MPa H{sub 2}S at 50 C, while the conventional 13Cr steel cracked. This is attributed to the decrease in dissolved hydrogen though the reduction of hydrogen production and penetration due to Ni addition.