借助CPFEM-CZM探究X80掺氢管道氢致裂纹扩展行为  

Investigation of hydrogen-induced crack propagation in X80 hydrogen-blended pipelines using CPFEM-CZM

作　　者：白熙贤 徐涛龙 贾彦琨 熊峰 荣恒 李又绿 BAI Xixian;XU Taoong;JIA Yankun;XIONG Feng;RONG Heng;LI Youv(School of Oil&Natural Gas Engineering,Southwest Petroleum University;PipeChina West-East Gas Pipeline)

机构地区：[1]西南石油大学石油与天然气工程学院 [2]国家管网集团西气东输分公司

出　　处：《管道保护》2025年第2期25-33,共9页

基　　金：国家自然科学基金项目“X80掺氢天然气管道环焊缝区微结构-应力-氢协同效应与氢脆失效机理多尺度研究”(52374068)。

摘　　要：利用现有天然气管网进行掺氢输送是实现氢能大规模利用的有效手段,然而管线钢的氢脆问题正制约着掺氢管道的快速发展,亟待通过试验与数值模拟相结合的手段开展氢致裂纹扩展行为研究,为掺氢管道的建设运行提供安全保障。以X80管道环焊缝热影响区为研究对象,通过电子背散射衍射观测试验获取了晶体取向与尺寸参数,并基于晶体塑性本构建立了有限元模型,将零厚度的内聚力单元嵌入晶粒之间模拟晶界,分析细观尺度下晶间微裂纹在不同氢气体积分数中的萌生与扩展行为。结果表明,内聚力单元晶界模型与已有观测试验结果相吻合,微裂纹易在多晶粒连接处的应力集中区域萌生并沿晶界向高应力区双向扩展;而在临氢环境下,初始裂纹扩展过程中逐渐有新裂纹生成与扩展,随后与原有裂纹相互合并,这一现象导致了与无氢环境的裂纹扩展路径不一致。此外,氢气的掺入降低了裂纹萌生应变,增加了微观结构裂纹萌生与扩展的风险。Utilizing the existing natural gas pipeline network for hydrogen-blended transportation is an effective approach to facilitate the large-scale adoption of hydrogen energy.However,hydrogen embrittlement in pipeline steel hinders the rapid development of hydrogen-blended pipelines.Urgent research on hydrogen-induced crack propagation behavior,incorporating both experiments and numerical simulations,is essential to ensure the safety of constructing and operating hydrogen-blended pipelines.Focusing on the heat-affected zone of X80 pipeline girth welds,crystal orientation and size parameters were determined through electron backscatter diffraction tests.A finite element model was developed using the crystal plasticity constitutive framework,with zero-thickness cohesive elements embedded between grains to simulate grain boundaries.This model was used to analyze the initiation and propagation of intergranular microcracks at the mesoscale for different hydrogen volume fractions.The results indicated that the cohesive element grain boundary model aligns with existing observational test outcomes.Microcracks are likely to initiate in stress concentration areas at the junction of multiple grains and propagate bidirectionally along grain boundaries toward high-stress areas.In a hydrogen environment,new cracks gradually form and expand during the initial crack propagation process,subsequently merging with the original cracks.This phenomenon results in a differing crack propagation path compared to that in a hydrogen-free environment.Additionally,hydrogen blending decreases crack initiation strain and heightens the risk of microstructural crack initiation and propagation.

关 键 词：X80掺氢管道 热影响区 氢致裂纹扩展 晶体塑性有限元法 内聚力模型 

分 类 号：TE89[石油与天然气工程—油气储运工程]