油气管道带磁原因及退磁方法

在油气长输管道维修更换作业中,为了缩短更换作业周期及减少剩磁对管道焊接质量的影响,需要对管道进行退磁作业。分析了导致油气管道带磁的原因:管道检测;外部存在磁场、电场;管道焊接与摩擦等。探讨了管道带磁对管道焊接、其他检测方法与管道寿命的影响。基于油气管道的退磁原理,提出3种管道退磁方法:直流退磁法、交流退磁法及永磁铁退磁法,以此提高油气管道在线焊接质量。研究结果对于工程实践中油气管道退磁方法的选择有一定的指导作用。

The reasons and demagnetization methods for magnetic oil and gas pipelines

During the maintenance and replacement of long-distance oil and gas pipelines, it is necessary to demagnetize the pipelines in order to shorten the replacement cycle and reduce the effect of residual magnetism on the welding quality of pipelines. In this paper, the reasons for the magnetism of oil and gas pipelines were analyzed, e.g. pipeline inspection, external magnetic field and electric field, pipeline welding and friction. Then, the effect of the magnetism of pipeline on its welding and service life and other pipeline inspection methods were studied. Finally, with the demagnetization principle of oil and gas pipeline as the beginning, three pipeline demagnetization methods were proposed to improve the on-line welding quality of oil and gas pipelines, including DC demagnetization method, AC demagnetization method and permanent magnet demagnetization method. The research results play a certain role in guiding the selection of demagnetization methods for oil and gas pipelines in engineering practice.