Corrosion Behaviors of Pipeline Steel in NaCl Solutions Containing H₂S and CO₂

The corrosion behaviors of an oil pipeline steel in NaCl solutions coutaining carbon dioxide and hydrogen sulfide were studied by electrochemical experiments and slow strain rate test(SSRT). The results of electrochemical experiments of 15# steel showed a state of active dissolution without active-passive transition, and the corrosion rate increased as the following order: in NaCl solution < in NaCl-CO2 solution < in NaCl-CO2-H2S solution < in NaCl-H2S solution, SSRT showed that the reduction in area decreased as the following order: in NaCl > in NaCl-CO2 > in NaCl-CO2-H2S > in NaCl-H2S solution. But the brittleness and stress corrosion cracking sensitivity increased gradually under the same conditions.