Test on the degaussing technology used in the welding of China-Russia Eastern Gas Pipeline

During the construction, rerouting and maintenance & repairing of long-distance pipelines, the phenomenon of magnetic partial blowing often occurs at pipeline junctions, which leads to the deviation of electric arc in the process of welding operation. As a result, welding defects appear and even the welding operation cannot be carried out, so as to seriously impact the progress of the project and the essential security of the pipeline. OD 1 422 mm and X80 steel grade pipeline is used in the China-Russia Eastern Gas Pipeline Project, and the degaussing methods and degaussing devices used in the past are unable to satisfy the degaussing requirements of large diameter and high steel grade pipelines. In this paper, the applicability of different degaussing methods to the China-Russia Eastern Gas Pipeline was clarified by analyzing the generation mechanisms and influencing factors of pipeline remanence. After DC degaussing method was verified by conducting field tests, DC degaussing and DC welder degaussing were analyzed from the aspects of advantage, disadvantage and working parameters. In addition, the feasible recommendations were proposed.