摘要
目的研究在役天然气管道掺氢输送条件下氢原子在管道腐蚀缺陷处的扩散和分布情况及应变对腐蚀缺陷处氢扩散行为的影响。方法利用COMSOL软件,将固体力学模型和扩散模型相结合,建立了基于有限元的氢原子扩散渗透模型,研究了在纵向拉伸应变作用下X80钢制管道不同尺寸腐蚀缺陷处氢原子的分布情况。结果在没有拉伸应变的情况下,氢原子一旦进入管道内,在浓度梯度的驱动下,沿径向梯度扩散到管道内。当在管道上施加应变时,氢原子的扩散受到静水应力的驱动。氢原子在腐蚀缺陷处的最大浓度超过了进入管道的氢原子初始浓度。结论氢原子在腐蚀缺陷处聚集。此外,施加的拉伸应变也影响氢原子聚集的位置,随着缺陷长度的减小和深度的增大,在内壁腐蚀缺陷处,更多的氢原子会集中在缺陷中心和尖端。
One potential issue in using existing natural gas pipelines to transport hydrogen in the form of hydrogen blending natural gas is hydrogen damage of high-strength pipeline steel.The hydrogen damage of pipelines is closely related to the diffusion and trapping of hydrogen atoms in pipeline steel.The diffusion and distribution of hydrogen atoms at corrosion defects in in-service natural gas pipelines under the condition of hydrogen blending transportation,and the effect of strain on hydrogen diffusion behavior at corrosion defects are unclear.In this paper,a hydrogen atoms diffusion model was established based on the finite element method by COMSOL software to combine the solid mechanics model and the diffusion model.The distribution of hydrogen atoms at different sizes of corrosion defects in X80 pipelines under longitudinal tensile strain was studied.The mechanical curve of X80 steel was obtained through experiments before modeling.This article adopted the Ramberg-Osgood(R-O)relationship for X80 steel in order to obtain better computational efficiency and accuracy,and to better describe the nonlinear mechanical properties of the material.For further analyzing the effect of strain on the hydrogen atom diffusion at the corrosion defect,a geometric model containing corrosion defects on the inner wall of the pipeline was established,in which the thickness of the pipeline wall was 12.7 mm and the length of the pipeline section was 3000 mm.For boundary conditions,assuming that no hydrogen atoms initially entered the steel,the initial diffusion surface was the interface between hydrogen and the inner surface of the pipeline(i.e.the inner wall of the pipeline),and the initial diffusion hydrogen atom concentration was 10 mol/m^(3).The loads were 0%,0.1%,0.2%,0.3%,0.5%,0.8%,and 1%longitudinal tensile strains to simulate the effect of ground motion.The local strain at the corrosion defect was variable.Afterwards,the grid was divided and solved using the direct solver MUMPS.Analyzing the results could lead to the following c
作者
刘韦辰
韦博鑫
尹航
许进
于长坤
孙成
LIU Weichen;WEI Boxin;YIN Hang;XU Jin;YU Changkun;SUN Cheng(Liaoning Shenyang Soil and Atmosphere Corrosion of Material National Observation and Research Station,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of MaterialsScience and Engineering,University of Science and Technology of China,Shenyang 110016,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2024年第8期84-92,132,共10页
Surface Technology
基金
国家自然科学基金(51871228)
中国科学院金属研究所创新基金(2023-PY12)。
关键词
X80管道
氢扩散
腐蚀缺陷
应变
有限元模拟
点蚀
X80 pipelines
hydrogen atom diffusion
corrosion defect
strain
finite element modeling
pitting
