摘要
采用高温高压动态腐蚀模拟实验,研究普通J55油管在65℃不同CO2分压条件下的的腐蚀行为,测量其腐蚀速率,使用扫描电镜观测腐蚀产物的结构特性,利用X-射线衍射分析腐蚀产物的成分。结果表明,J55油管腐蚀速率随CO2分压的增大呈先减小后增大的趋势,在1 MPa CO2分压时取得最小值;CO2分压越高,J55油管的腐蚀越严重,但腐蚀速率增长变缓;在高CO2分压条件下,不仅介质的腐蚀性增强,而且腐蚀产物膜保护性能降低,膜层局部缺陷(如孔洞)是导致J55油管基体表面点蚀的主要诱因;CO2分压的升高促进了钙盐和镁盐的沉积,在高CO2分压条件下,腐蚀产物不仅含有FeCO3和少量的Fe3C,还含有复盐Fe(Ca,Mg)(CO3)2。
The corrosion tests of J55 tubing under different CO2 partial pressures at 65℃ were carried out by using high-temperature and high-pressure autoclave. The mass loss of J55 tubing under different CO2 partial pressures were measured, the structural features of corrosion scales were observed by SEM, and the composition of corrosion scales were analyzed by XRD. The results show that with CO2 partial pressure increasing, the average corrosion rate of J55 tubing decreases firstly and then increases, and the minimum value is presented under 1MPa CO2 partial pressure. The higher CO2 partial pressure, the bigger the corrosion rate, while the slower the gradient of the corrosion rate. At higher CO2 partial pressure, the corrosivity of the solution increases, the protection property of corrosion scales becomes worse, and the local defects （such as holes） of corrosion scales are responsible for the pitting corrosion of metal matrix. Increasing CO2 partial pressure can promote the deposition of calcium salt and magnesium salt. CO2 corrosion scales of J55 tubing are composed of double salt Fe（Ca, Mg）（CO3）2 besides FeCO3 and a trace of Fe3C at high CO2 partial pressure.
出处
《热加工工艺》
CSCD
北大核心
2014年第4期59-63,共5页
Hot Working Technology
基金
西安石油大学博士科研启动项目(2012BS001)
