聚乙烯燃气管道电熔连接界面失效部位老化性能研究

Study on the Aging Performance at Failure Sites of Polyethylene Gas Pipeline Electrofusion Joint Interface

摘要: 近年来，随着聚乙烯管道(HDPE)在城镇燃气管网领域的广泛应用，城镇PE燃气管道失效漏气引发的安全问题得到极大关注，城镇燃气管网漏气部位多发生在管道电熔连接处。本文基于城市PE燃气管漏气失效案例，对漏气失效的电熔连接管件进行结构缺陷与老化性能的深入剖析。结果表明，电熔连接界面的质量缺陷部位发生了老化性能劣化，结晶度逐渐降低，氧化诱导时间显著缩短，热氧化稳定性下降；同时，电熔连接界面存在显著的孔洞、微裂纹及界面不均匀性，漏气附近电熔连接界面剥离时表现出明显的脆性断裂特征；服役环境的应力作用在结构弱化的电熔连接界面，导致PE燃气管道电熔连接部位失效漏气；提出PE燃气管道的漏气与服役环境、结构之间的关系。

Abstract: In recent years, with the widespread application of polyethylene (HDPE) pipelines in urban gas networks, the safety issues caused by failures and gas leaks in PE gas pipelines have gained significant attention. The majority of leaks in urban gas networks occur at the electrofusion joints of the pipelines. This study, based on cases of leakage failures in urban PE gas pipelines, conducts an in-depth analysis of structural defects and aging performance in failed electrofusion joints. The results reveal that areas of quality defects in the electrofusion interface exhibit degradation in aging performance, with crystallinity gradually decreasing, oxidation induction time significantly shortening, and thermal oxidative stability deteriorating. Furthermore, the electrofusion interface shows notable defects, including pores, microcracks, and interface irregularities. When peeling the electrofusion joint near the leakage site, clear signs of brittle fracture were observed. The combined effects of environmental stress and structural weakening at the electrofusion interface ultimately lead to failures and gas leaks in PE gas pipelines. The study also establishes the relationship between gas leakage, service conditions, environmental factors, and structural integrity in PE gas pipelines.