X65钢在高温高压CO2酸性溶液中的腐蚀行为

利用高温高压釜,通过失重法、SEM、XRD以及电子探针微观结构分析等方法,研究了X65钢在四种不同高温条件下及1 MPa分压的饱和CO2的NACE酸性溶液中的腐蚀行为。结果表明:(1)在所研究的温度范围内,X65钢在CO2腐蚀介质中表现出高的腐蚀速率;随着温度的升高,腐蚀速率呈先下降再升高的趋势,90℃时最小;(2)表面生成了FeCO3为主的腐蚀产物膜;(3)CO2腐蚀的作用形成了钢表面点蚀、坑蚀、台地腐蚀特征;(4)Cl-为点蚀的"激发剂",并且在点蚀坑内富集,导致局部Cl-浓度差不同,促进点蚀发生;(5)CO2腐蚀是各种因素相互作用的结果。

Corrosion Behavior of X65 Steel in Carbon Dioxide Solution under High Temperature and High Pressure

Corrosion characteristics of X65 steel under four different high temperatures and in NACE solution saturated with CO2 at 1 MPa partial pressure were investigated by using autoclave,SEM,XRD,weight loss methods and electron-probe micro-analysis.The result showed that in the studied temperature ranges,X65 steel was corroded seriously by CO2.With the temperature increasing,the corrosion rate of X65 steel had a tendency of decreasing first,then increasing,and the minimum rate appeared at the temperature of 90℃.The main corrosion scale is ferrous sulfide.The effect of CO2 corrosion made the surface of X65 steel have a feature of point corrosion,pitting corrosion and mesa corrosion.Cl-excited point corrosion and enriched in the pit of point corrosion,which brought the concentration of Cl-on part surface of sample different,and accelerated the point corrosion reaction.The corrosion of CO2 was the result of interaction of multi-factors.