流动状态下X65管线钢CO_2腐蚀产物膜结构和力学性能的评价

INVESTIGATION OF STRUCTURE AND MECHANICAL PROPERTIES OF CO_2 CORROSION SCALE FORMED UNDER VARIOUS FLOW RATES

针对油气行业常用的X65管线钢,研究了含CO_2腐蚀介质中钢表面形成的腐蚀产物膜结构和力学性能的特征以及介质流动造成的影响。结果表明,静态条件下形成的腐蚀产物膜的主要成分为(Fe,Ca,Mg)CO_3,动态条件下的主要成分为(Fe,Ca)CO_3;介质的流动能够促进腐蚀产物膜的形成,但对膜的硬度以及杨氏模量影响不大;腐蚀产物膜的断裂韧性随着流速的增大先下降后上升,流动状态下内层腐蚀产物膜的致密性较好,膜与基体的结合强度较高。

The structure and mechanical properties of CO2 corrosion scale formed on X65 pipeline steel in simulated CO2 corrosion environment in oil field under various flow rates were investigated.XRD and EDS analysis indicate that at static condition,the composition of the scale is（Fe,Ca,Mg）CO3,while the scale changes to（Fe,Ca）CO3 at dynamic conditions.The increment in flow rate increased the thickness of the scale remarkably,but had little influence on the hardness and Young s modulus of the scale.The fracture toughness of the scale exhibited the lowest value at the flow rate of 0.5 m/s, whereas the adhesion strength increased with increasing the flow rate.