高含H_2S/CO_2环境中P110钢应力腐蚀

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

用恒载荷拉伸法,结合腐蚀电化学测试技术和断口扫描电镜(SEM)分析技术,研究了P110钢在H_2S/CO_2NACE标准溶液中的硫化物应力腐蚀(SSCC)行为。结果表明,随着溶液中的H_2S含量增高,P110钢的自腐蚀电位(E_(corr))急剧下降,至极小值后缓慢升高,约5 h后达到稳定值直至断裂,试样呈解理状脆性断口;随溶液中通入CO_2量的增大,P110钢的自腐蚀电位(E_(corr))稍有增高,自腐蚀电流(I_(corr))减小,试样断裂时间延长,断口由脆性解理向韧窝状韧性转化。这种现象的产生与H_2S/CO_2在钢表面的竞争吸附及P110钢在应力腐蚀环境中表面膜的拉伸破裂与再生有关。

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.