饱和CO_(2)溶液中Cl^(-)浓度对马氏体不锈钢应力腐蚀敏感性的影响  

Effect of Cl^(-) Concentration on the Stress Corrosion Sensitivity of Martensitic Stainless Steel in Saturated CO_(2) Solution

作　　者：赵雪会 刘君林[3] 曾瑞华[4] 胥聪敏 徐秀清[1] ZHAO Xue-hui;LIU Jun-lin;ZENG Rui-hua;XU Cong-min;XU Xiu-qing(CNPC Tubular Goods Research Institute,State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Fquipment Materials,Xi'an 710077,China;Xi'an Jiaotong University,State Key Laboratory for Mechanical Behavior of Materials,Xi'an 710049,China;Drilling and Production Technology Research Instiute of Qinghai Oifield,Dunhuang 736202,China;Engineering and Technology Department of South Petroleum Exploration and Development Co,Lid.,Haikou 570100,China;School of Materials Science and Engineering,Xi'an Shiyou University,Xi'an 710065,China)

机构地区：[1]中国石油集团石油管工程技术研究院石油管材及装备材料服役行为与结构安全国家重点实验室,陕西西安710077 [2]西安交通大学金属材料强度国家重点实验室,陕西西安710049 [3]青海油田钻采工艺研究院,甘肃敦煌736202 [4]南方石油勘探开发有限责任公司工程技术处,海南海口570100 [5]西安石油大学材料学院,陕西西安710065

出　　处：《材料保护》2021年第1期36-44,共9页Materials Protection

基　　金：国家自然科学基金青年科学基金项目(51904331);中国石油天然气集团公司重大专项科技项目(2014E-3603)资助。

摘　　要：为了明确Cl-浓度的变化对超级13Cr马氏体不锈钢耐蚀性能的影响规律,利用电化学动电位测试技术对比分析了Cl-浓度对超级13Cr腐蚀电位的影响关系;采用慢应变速率拉伸(SSRT)应力腐蚀开裂(SCC)试验方法和应力-应变曲线(σ-ε)、扫描电镜(SEM)等分析手段,研究了饱和CO2环境下在一定慢应变速率条件下Cl-浓度的变化对超级13Cr马氏体不锈钢的抗拉强度、延伸率、应力腐蚀敏感指数(ISSRT)的影响,并结合断口形貌分析了材料的断裂特征。结果表明:在Cl-浓度≤60 g/L的饱和CO2溶液中,超级13Cr相对于空气中强韧性变化不大,属于韧性断裂模式;随着Cl-浓度的增大,材料的断裂寿命和伸长率均逐渐降低;材料断裂模式由韧性断裂逐渐转变为韧性-脆性混合断裂模式;当Cl-浓度增大到90 g/L时,断口侧面开始出现二次裂纹;当Cl-浓度≥120 g/L时,材料点蚀电位明显降低,点蚀敏感性增大,同时断口侧面出现点蚀现象,进一步促进了应力腐蚀开裂。The purpose of this paper is to clarify the influence rule of Cl- concentration changes on the corrosion resistance of super 13 Cr Martensite stainless steel. The influence of Cl- concentration on the corrosion potential of super 13 Cr was compared and analyzed by electrochemical potentiometric test. In addition,the influence of Cl- concentration on the tensile strength,elongation and stress corrosion sensitivity index( ISSRT) of super 13 Cr martensitic stainless steel under a certain slow tensile rate in saturated CO2 solutions were studied by the means of slow strain rate tensile( SSRT) SCC test,stress-strain curve( σ-ε) and scanning electron microscope( SEM). Furthermore,the fracture characteristics of the materials were researched by the fracture morphology. Results showed that in the saturated CO2 solution with Cl- concentration lower than 60 g/L,super 13 Cr had little change in strength and toughness compared with that in the air,which belonged to the ductile fracture mode;with the increase of Cl-concentration,the fracture life and elongation of the material decreased gradually;the fracture mode of the material changed from the ductile fracture to the ductile brittle mixed fracture mode;when Cl- concentration increased to 90 g/L,the second crack began to appear at fracture side. When Cl-concentration was higher than 120 g/L,the pitting potential of the material decreased significantly,the pitting sensitivity increased,and the pitting phenomenon appeared on the side of the fracture,which further promoted the stress corrosion cracking.

关 键 词：超级13Cr不锈钢 SCC 应力-应变 断裂 点蚀 Cl-浓度 饱和CO2环境 

分 类 号：TG172[金属学及工艺—金属表面处理]