基于矫顽力的管道环焊缝应力测量及应力集中分布的研究

Research on Stress Measurement and Stress Concentration Distribution of Pipeline Girth Weld Based on Coercivity

长输管道沿线地貌地质错综复杂,由于地质、气候灾害(沉降、滑坡、冻胀等)的影响,埋地管道容易发生变形,产生应力集中,严重时会导致管道断裂失效,给管道的安全运行带来严重隐患。根据管道事故调查显示管道失效位置大多在管道的焊缝区,因此寻找一种快速、不损伤管道、无辐射污染的便捷检测评价管道焊缝应力及应力集中的方法具有重要的研究意义。本文对矫顽力测试应力的基本原理、研究现状和生产实践进行了调研,在实验室采用盲孔法、超声法、矫顽力法进行了X80焊接管段环焊缝应力的测量实验,结果表明矫顽力法应力测量技术可以实现管道焊缝区应力的测量和应力集中快速评估。相比于盲孔法,矫顽力法测量速度快、操作简便、无需打磨、对管道没有损伤,更适合现场进行应用。

The geomorphology along the long-distance pipeline is very complicated.Due to the influence of geological and climatic disasters(subsidence,landslide,frost heave,etc.),buried pipelines are prone to deformation and stress concentration,which will lead to pipeline fracture and failure in serious cases,bringing serious hidden dangers to the safe operation of pipelines.According to the pipeline accident investigation,the failure location of the pipeline is mostly in the weld zone of the pipeline.Therefore,it is of great research significance to find a fast and convenient method to detect and evaluate the stress and stress concentration of the pipeline weld without damaging the pipeline and radiation pollution.In this paper,the basic principle,research status and production practice of coercivity testing stress are investigated.In the laboratory,blind hole method,ultrasonic method and coercive method were used to measure the stress of girth weld of X80 welded pipe segment.The results show that the coercivity stress measurement technique can realize the stress measurement and stress concentration evaluation in the weld zone of pipeline.Compared with the blind hole method,the coercivity method is more suitable for field application because of its high speed,simple operation,no grinding and no damage to the pipeline.