油田集输系统中不同CO2分压下16Mn钢的腐蚀行为

摘要

采用浸泡试验、电化学试验等方法研究了16Mn钢在模拟油田集输系统中不同CO2分压(0,0.15,0.3 MPa)下的腐蚀行为.结果表明:16Mn钢的腐蚀速率随CO2分压的增加呈先增大后减小的变化趋势;当CO2分压为0时,16Mn钢表面未形成腐蚀产物膜,为均匀腐蚀;当CO2分压为0.15 MPa时,腐蚀产物膜较完整致密,为均匀腐蚀;当CO2分压为0.30 MPa时,腐蚀产物膜变薄并有明显缺陷,为典型的台地腐蚀;16Mn钢表面的腐蚀产物主要是FeCO3;16Mn钢的腐蚀反应主要以阳极活化溶解为主,电化学阻抗谱的中频感抗弧与腐蚀产物的溶解吸收有关,低频容抗弧与腐蚀产物膜覆盖区的活化溶解有关.%The corrosion behavior of 16Mn steel in the stimulating environment of oil field gathering and transporting system with different CO2 partial pressure was investigated by dipping test and electrochemical test. The results show that the corrosion rate of 16Mn steel increased first then decreased with the increase of CO2 partial pressure.The corrosion product scale was not formed on the surface of 16Mn steel when CO2 partial pressure was 0 and the type of corrosion was uniform corrosion.The corrosion product scale was complete and compact at the CO2 partial pressure of 0.15 MPa and the type of corrosion was uniform corrosion.When CO2 partial pressure was 0.30 MPa,the corrosion product scale became thinner and defects occurred,and the type of corrosion was platform corrosion.The main corrosion product on the surface of 16Mn steel was FeCO3 .The major corrosion behavior of 16Mn steel was anodic active dissolution.The middle frequency inductive loop of electrochemical impedance spectroscopy was related to the dissolution and absorption of corrosion products.The low frequency capacitive loop was related to the active dissolution of corrosion scale covered area.