Liu Wenhui, Meng Yanbing, Zhao Jun, Wen Wen, Gong Ming, Wu Shixiong, Li Songmei, Yu Mei, Liu Jianhua
School of Material Science and Engineering, Beihang University, Beijing 100191, China.
PipeChina Science and Technology Institute, Langfang 065000, China.
Materials (Basel). 2022 Aug 11;15(16):5526. doi: 10.3390/ma15165526.
For the application of X80 pipelines in Northeast China, it is important to establish the correct cathodic protection (CP) potential. To achieve this, potentiodynamic polarization; electrochemical impedance spectroscopy (EIS); a slow strain rate test (SSRT); and a scanning electron microscopy (SEM) fracture morphology analysis were carried out for an X80 steel gas pipeline at several temperatures in Heilongjiang Province, China. The results show that the hydrogen evolution potential of X80 steel in soil at different temperatures was about -900 mV (vs. CSE). The generated hydrogen atoms can be adsorbed on the surface of the pipelines to reduce the surface energy, or they can be diffused into the substrate and accumulate to the critical concentration, inducing the decohesion between different structures and generating additional plastic deformation through dislocation motion. With the peak impedance potential as the minimum potential and the hydrogen embrittlement potential as the maximum potential, the CP potential of X80 steel in the soil at 30 °C, 45 °C, and 60 °C ranged from -900 mV to -1100 mV (vs. CSE), temperatures at which the X80 steel does not corrode or cause hydrogen embrittlement.
对于X80管道在中国东北地区的应用，确定正确的阴极保护（CP）电位很重要。为此，在中国黑龙江省对一条X80钢燃气管道在多个温度下进行了动电位极化、电化学阻抗谱（EIS）、慢应变速率试验（SSRT）以及扫描电子显微镜（SEM）断口形貌分析。结果表明，不同温度下X80钢在土壤中的析氢电位约为-900 mV（相对于饱和硫酸铜参比电极，CSE）。产生的氢原子可吸附在管道表面以降低表面能，或者扩散到基体中并积累至临界浓度，引发不同组织间的脱粘，并通过位错运动产生额外塑性变形。以峰值阻抗电位为最小电位、氢脆电位为最大电位，30℃、45℃和60℃时X80钢在土壤中的CP电位范围为-900 mV至-1100 mV（相对于CSE），在此温度范围内X80钢不会发生腐蚀或导致氢脆。
