高温高压CO_2环境介质中X60钢的腐蚀

Corrosion Behavior of X60 Steel in CO_2 Environment at High Temperature and High Pressure

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X60钢在不同高温条件下及2MPa分压的饱和CO_2的环境介质中的腐蚀行为。结果表明:在90℃、120℃、150℃温度下,X60钢发生了严重的CO_2腐蚀,表现出高的腐蚀速率,且腐蚀速率随着温度的升高呈先上升再下降的趋势,120℃时最大,表面腐蚀产物膜的主要成分为Fe_3C和FeCO_3。腐蚀过程显示局部腐蚀特征,为不同程度的点蚀和条状腐蚀。研究发现,Cl^-为点蚀的"激发剂",促进了点蚀的发生和发展。CO_2腐蚀受温度、腐蚀产物膜、钢的显微组织、Cl^-等影响,是各种因素相互作用的结果。

The corrosion characteristics of X60 steel at three high temperatures and in the environment of CO2 at 2MPa partial pressure were investigated in autoclave by weight loss evaluation along with SEM, XRD and electronprobe micro-analysis. The results showed that at 90℃, 120℃ and 150℃, the steel was attacked seriously by the CO2 and exhibited rather high corrosion rate. With the temperature increasing, the corrosion rate showed a peak, and the maximum rate appeared at 120 ℃. The main corrosion scale consisted of Fe3C and FeCO3. In the experimental process, the features of localized corrosion was presented, i. e. pitting corrosion and strip corrosion. Cl^- was the excitant to pitting corrosion. The CO2 corrosion was affected by a series of factors including temperature, corrosion product scale, microstructure of steel, and Cl^-, etc.