长期服役环境下城镇PE燃气管道电熔焊接界面结构与老化性能研究  

Structure and Aging Performance of Electro-fusion Welded Interfaces in Urban PE Gas Pipelines under Long-term Service Conditions

作　　者：邱迪 李孟垠 种万臣 倪志国 王飞 辛妍 李翌翀 高瑾 QIU Di;LI Mengyin;ZHONG Wanchen;NI Zhiguo;WANG Fei;XIN Yan;LI Yichong;GAO Jin(Beijing Gas Group Co.,Ltd.,Beijing 100032,China;Institute of Advanced Materials Technology,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京燃气集团有限责任公司,北京100032 [2]北京科技大学新材料技术研究院,北京100083

出　　处：《装备环境工程》2025年第2期114-125,共12页Equipment Environmental Engineering

摘　　要：目的 研究电熔焊接界面在长期服役期间的老化性能及其变化规律。方法 以服役30 a的PE燃气管道电熔焊接管件和新焊管件为样本,通过超声相控阵无损检测和解剖的方法分析焊接界面的结构性能,通过氧化诱导时间测试、红外光谱测试和结晶度测试对PE管的中间部位、焊接界面的老化行为进行对比研究。通过对服役焊接管件附近土壤进行分析,确定影响管件服役老化的化学介质。结果 长期服役的PE电熔焊接界面存在不同程度的结构缺陷,尤其在焊接界面处发生了明显的性能弱化。焊接界面的热氧稳定性和结晶性能均低于管材中间部位,而管材中间部位的性能则低于新焊界面。相比新焊管件,服役30 a的PE电熔焊接界面出现C—O—老化峰,发生一定程度老化。经检测,土壤中存在的胺类、酮类和醇类有机物(如十二烷基二甲基叔胺)具有显著的化学活性,会对PE材料产生老化作用。结论 土壤的温度及化学介质带来PE燃气管道电熔焊接部位C—O老化基团的产生,将破坏聚乙烯的结构规整性,导致其结晶度的下降,影响到了电熔焊接界面的力学结合性能。本研究证实了土壤环境对PE带来的负面影响,影响其使用寿命和安全性,应加强关注土壤环境对PE燃气管道的长期服役安全问题。The work aims to study the aging performance and its changing law of the electro-fusion welded interfaces under long-term service.With the electro-fusion welded pipeline fittings and new welded pipeline fittings of PE gas pipeline in service for 30 years as samples,the structural performance of the welded interface was analyzed by ultrasonic phased array nondestruc-tive testing and dissection,and the aging behavior of the middle part and welded interface of the PE pipeline was compared by oxidation induction time test,infrared spectrum test and crystallinity test.By analyzing the soil near the welded pipeline fittings in service,the chemical medium that affected the aging of the pipeline fittings in service was determined.The PE electro-fusion welded interface had different degrees of structural defects under long-term service,especially the obvious performance weak-ening at the welded interface.The thermal oxygen stability and crystallization properties of the welded interface were lower than those of the middle part of the pipeline,while the properties of the middle part of the pipeline were lower than those of the new welded interface.Compared with the new welded pipeline,the electro-fusion welded interface of PE in service for 30 years had C-O-aging peak,which led to a certain degree of aging.After testing,amines,ketones and alcohols(such as dodecyl dime-thyl tertiary amine)existing in the soil had obvious chemical activity and caused aging effect on PE materials.The temperature of soil and chemical medium bring about the generation of C-O aging groups in the electro-fusion welded part of PE gas pipe-line,which will destroy the structural regularity of polyethylene,lead to the decrease of its crystallinity,and affect the mechani-cal bonding performance of the electro-fusion welded interface.This study confirms the negative impact of soil environment on PE,affecting its service life and safety,so more attention should be paid to the long-term service safety of PE gas pipeline.

关 键 词：电熔焊接 界面老化 PE管道 土壤环境 城市燃气 

分 类 号：TU996.7[建筑科学—供热、供燃气、通风及空调工程]