STRESS CORROSION CRACKING OF P110 IN ENVIRONMENT OF HIGH CONTENTS OF H_2S AND CO_2

The constant load tensile test,with combination of electrochemical corrosion technology and SEM analysis method,were performed to study sulfide stress corrosion cracking(SSCC)of P110 steel in H_2S/CO_2 NACE standard solution.The results show that,with the increase H_2S content,the corrosion E_(corr)of P110 steel dropped sharply and increaseed slowly again after reaching minimum point.Then the corrosion E_(corr)increased to constant point about five hours until fracture phenomenon occurring,and the sample appear brittle cleavage fracture.With the content of CO_2 increasing in the solution,the E_(corr)potentials of steel P110 increased, the corrosion current decreased,the time of fracture extended and the brittle cleavage fracture transformed to toughness dimples.The generation of this phenomenon has the relevant combination of competitive adsorption of H_2S/CO_2 in steel surface and tensile breakdown and regeneration of P110 surface membrance in stress corrosion environmental.