天然气放空管线断裂失效原因分析

埋地天然气放空管线是是集输体系重要的组成部分，借助宏观检查、材质分析、金相分析和力学性能测试等手段，对发生断裂的天然气埋放空线的宏观断1：7形貌、显微组织、力学性能等进行了研究，寻找管线发生断裂的原因，为以后类似管线的生产安装提供参考。结果表明，该管线在埋地过程中，管线受到了外力作用，使管线在最大变形处产生了很大的应力，最终发生脆性断裂。这就要求我们在埋地管线施工中，除了严格检查材料本身的质量依据有关标准，施工阶段合理保障管线不受外界因素的破坏，对每一个施工环节都要保证施工质量，确保管线能承压，不堵塞，符合设计的全部要求，才不至于出现一系列安全事故和质量事故的发生。

Cause Analysis of Fracture Failure of Natural Gas Vent Line

Buried natural gas vent line is an important part of gathering pipeline system.With the help of macro examination,material testing,metallographic analysis and mechanical performance testing,the fracture morphology,the microstructure and mechanical properties,etc are studied and cause of fracture of fractured buried NG vent lines are found out,which provides a good reference for the safe operation of similar pipelines.The results show that,in burying the pipeline,a great stress was produced at the highly deformed section of the pipeline due to the external force,resulting in brittle fracture.Therefore,in the construction of buried pipelines,the pipelines should be properly protected from the damages of external factors in addition to the strict inspection of pipeline quality in accordance with applicable standards before the construction.The pipeline should be protected from external damages.The construction quality must be controlled in each construction stage to guarantee that the pipeline can sustain the required pressure,there is no plugging and design requirements are met.These will make it possible that there will be no occurrence of safety and quality-related accidents.