Study on H₂S and CO₂ Corrosion Behavior of High Strength and Toughness 15Cr Stainless Steel

The corrosion behavior of high-strength and toughness 15 Cr stainless steel under H₂S and CO₂ production conditions was studied by sulfide stress cracking（SSC）, stress corrosion cracking（SCC） tests, high temperature and high pressure corrosion simulation tests and in-situ electrochemical tests. The results show that under NACE TM0177 standard conditions（B solution） and simulated working conditions（90 ℃, 3 MPa CO₂, 2 kPa H₂S）, the SSC and SCC sensitivity of high-strength and toughness 15 Cr stainless steel are low, showing excellent resistance to hydrogen sulfide stress corrosion cracking. Under the conditions of ultra-high temperature, ultra-high CO₂ and low H₂S partial pressure, the high strength and toughness 15 Cr exhibits good resistance to uniform corrosion and local corrosion. Compared with the partial pressure of CO₂ and H₂S, the influence of temperature on the corrosion rate is more significant, and its applicable temperature can reach 220 ℃（with a uniform corrosion rate of 0.09 mm/a and no obvious pitting corrosion）. Under simulated conditions, p-n bipolar passivation film is formed on the surface of high-strength and toughness 15 Cr. Compared with Super 13 Cr, it has lower doping concentration(N_A=7.95×10²²cm^-3, N_D=1.87×10²²cm^-3), higher pitting protection potential（E_p=-148 mV）, and polarization resistance（R_p=6048.69 Ω ·cm²）, and higher corrosion resistance. The research results provide a theoretical basis for the use of high strength and toughness 15Cr stainless steel in H₂S and CO₂ environment.