外径1422 mm、X80高钢级输气管道的消磁技术  

Degaussing technology for OD 1 422 mm X80 high steel grade gas line pipes

作　　者：刘少柱[1] 徐葱葱 李景昌[1] 齐健龙 张洪雷[2] 于雷[2] 王强[3] 陈久龙[2] LIU Shaozhu;XU Congcong;LI Jingchang;QI Jianlong;ZHANG Honglei;YU Lei;WANG Qiang;CHEN Jiulong(PetroChina Pipeline Company,Langfang,Hebei 065000,China;Daqing Oil&Gas Transportation Sub-Company,PetroChina Pipeline Company,Daqing,Heilongjiang 163000,China;Hohhot Oil&Gas Transportation Sub-Company,PetroChina Pipeline Company,Hohhot,Inner Mongolia 010000,China)

机构地区：[1]中国石油管道公司,河北省廊坊市065000 [2]中国石油管道公司大庆输油气分公司 [3]中国石油管道公司呼和浩特输油气分公司

出　　处：《天然气工业》2020年第9期131-137,共7页Natural Gas Industry

基　　金：国家重点研发计划项目“公共安全风险防控与应急技术装备”重点专项“油气长输管道及储运设施检验评价与安全保障技术”(编号:2016YFC0802100)。

摘　　要：油气管道组对焊接过程中,管端管口处经常存在着剩磁,当剩磁较大时易发生磁偏吹,有可能影响焊接施工进度和焊接质量。中俄东线天然气管道工程首次采用外径1 422 mm大口径、X80高钢级管道,现有的消磁方法和消磁设备对其适用性难以确定。为此,通过分析管道剩磁产生的机理,探讨了不同消磁技术的原理和优缺点,选取直流消磁技术开展现场试验,分析了国内外典型直流消磁设备的消磁能力,进而开展了磁感应强度对焊接影响、经验判断方法和空间分布规律试验。研究结果表明:①现有的直流消磁设备消磁能力差异较大,试验所选用的A型号直流消磁设备针对外径1 422 mm、X80管道最大消磁能力可达490 mT,并且具有电压补偿功能,消磁能力和稳定性较高,而其余设备的消磁能力则相对较弱,难以满足大口径、高钢级输气管道强磁力情况下的现场消磁需求;②直流焊机以及永磁铁等消磁方法的消磁能力较弱,可以作为在施工现场没有专用消磁设备时的一种备选消磁法,仅适用于磁感应强度较低、局部开展消磁的情况;③为了确保焊接质量,实际作业过程中,当管口剩磁小于5 mT时方可进行焊接作业,此时剩磁对焊接影响可忽略;④剩磁在管端轴向和周向上分布不均匀,现场消磁时需局部调整。结论认为,该研究成果可以为大口径、高钢级输气管道消磁及焊接作业提供支撑。During the assembly welding of oil and gas line pipes, there is often residual magnetism at the pipe ends. And when the amount of the residual magnetism is higher, magnetic blow tends to occur easily and may impact welding schedule and welding quality. The Russia-China Eastern Route Pipeline Project adopts OD 1 422 mm X80 high steel grade pipes for the first time, so it is difficult to define the applicability of existing degaussing methods and equipment to such pipes. by analyzing the formation mechanisms of residual magnetism, this paper discussed the principles, advantages and disadvantages of different degaussing technologies. Then, DC degaussing technology was selected for field tests, and the degaussing capacity of domestic and foreign typical DC degaussing equipments was analyzed. Finally, the welding influence, empirical discriminant method and spatial distribution law of magnetic induction intensity were tested. And the following research results were obtained. First, existing DC degaussing equipment varies greatly in degaussing capacity. Type A DC degaussing equipment adopted in the test can provide the maximum degaussing capacity of 490 mT in OD 1 422 mm X80 pipes. And it has the function of voltage compensation and its degaussing capacity and stability is higher. However, the rest equipment has lower degaussing capacity and can hardly meet the field degaussing needs of large-diameter high steel grade gas pipes under a strong magnetic force. Second, DC welding machine and permanent magnet have lower degaussing capacity, so they can be used as an alternative degaussing method when there is no special degaussing equipment on site, and it is only suitable for low magnetic induction intensity and local degaussing. Third, in order to ensure the welding quality in the actual operation, it is required that welding operation be conducted when the residual magnetism at the pipe end is less than 5 mT. At this time, the influence of residual magnetism on welding operation can be ignored. Fourth, residual magnetis

关 键 词：中俄东线天然气管道工程 外径1422 mm管道 X80钢级 大口径管道消磁技术 直流消磁 焊接 维抢修 

分 类 号：TE973.3[石油与天然气工程—石油机械设备]