X70钢在高温高压二氧化碳酸性溶液中的腐蚀行为

Corrosion behavior of steel X70 in acid solution of carbon dioxide at high temperature and under 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X70钢在3种不同高温条件下及2 MPa分压的饱和CO2环境介质中的腐蚀行为.结果表明,在所研究的温度范围内,X70钢在CO2环境介质中表现出高的腐蚀速率;随着温度的升高,腐蚀速率呈上升再下降的趋势,120℃时为最大值;表面腐蚀产物膜的主要成分为Fe3C和FeCO3;CO2腐蚀的作用形成了钢表面点蚀、条状腐蚀特征,EPMA分析显示碳元素也呈条状分布;试样中沿轧制方向的两相对平行侧面的点蚀特征明显,而垂直于轧制方向的两相对平行侧面点蚀极少;CO2腐蚀是各种因素相互作用的结果.

The corrosion behavior of steel X70 under the condition of three sets of high temperatures and in the environment of CO2 under 2 MPa partial pressure were investigated in autoclave with weight loss method, SEM, XRD, and electron-probe micro-analysis. The result showed that, within the temperature ranges used, the steel X70 was corroded seriously by the COz environment medium; with increasing temperature, the corrosion rate showed the tendency of increasing first and then decreasing, and the maximum rate appeared at the temperature of 120 ℃ ; the main corrosion scale was of FesC and FeCO3; the CO2 corrosion made the surface of steel X70 of the corrosion feature such as point-corrosion, strip-corrosion , and the map distribution of element carbon, （analyzed by the EPMA）, also exhibited strip feature. The two sides of sample, parallel to the rolling direction exhibited remarkable point-corrosion feature. Other two parallel sides of sample, perpendicular to the roiling direction exhibited little point-corrosion feature. The corrosion of CO2 was the result of interaction of multiple factors.