永磁式流量计安装焊接过程中的磁偏吹影响及其应对措施  

The influence of magnetic bias blowing during installation and welding of permanent magnet flowmeter and its countermeasures

作　　者：杨洪旭 王超 邹明伟 邓立新 陈圣勇 慕长莉 YANG Hongxu;WANG Chao;ZOU Mingwei;DENG Lixin;CHEN Shengyong;MU Changli(CNNP Xiapu Nuclear Power Co.,Ltd,Xiapu 355100,China;Chongqing Chuanyi Automation Co.,Ltd,Chongqing401121,China)

机构地区：[1]中核霞浦核电有限公司,霞浦355100 [2]重庆川仪自动化股份有限公司,重庆401121

出　　处：《自动化与仪器仪表》2022年第6期228-232,共5页Automation & Instrumentation

基　　金：国家重点研发计划项目“特种工况实时在线测量仪表开发与示范应用”(2018YFB2003900)。

摘　　要：永磁式流量计在安装焊接时,焊接电弧受到电磁力的作用发生磁偏吹现象,影响正常焊接和焊缝质量。对磁偏吹产生的各种原因进行了介绍,并进行了理论分析,提出了相应的减小磁偏吹的措施。根据永磁流量计在安装焊接中遇到的实际问题,分析得到产生磁偏吹的主要原因为永磁流量计的磁钢漏磁造成焊接时焊接位置的磁场不对称性。针对该原因提出了应对措施,设计焊接屏蔽工装屏蔽漏磁,消除磁钢对焊接的影响。通过焊接试验并对焊缝进行X射线探伤和渗透探伤,发现该措施能够到达消除磁偏吹的目的,分析得到焊缝处的磁通密度在5 mT以内时,磁偏吹现象非常微弱,可以正常焊接,焊接完成后观察到焊缝外观良好,焊缝无缺陷。When the permanent magnet flowmeter is installed and welded,the welding arc is subjected to electromagnetic force to cause magnetic bias,which affects the normal welding and weld quality.This article introduces the various causes of magnetic bias,and carries out a theoretical analysis,and proposes corresponding measures to reduce the magnetic bias.According to the actual problems encountered in the installation and welding of the permanent magnetic flowmeter,the main reason for the magnetic bias blow is analyzed:the magnetic steel leakage of the permanent magnetic flowmeter causes the asymmetry of the magnetic field at the welding position during welding.This article proposes countermeasures for this reason,designing welding shielding tooling to shield magnetic leakage,and eliminate the influence of magnetic steel on welding.Through welding tests,X-ray inspection and penetrant inspection of welds,it is found that this measure can achieve the purpose of eliminating magnetic bias.The analysis shows that when the magnetic flux density at the weld is within 5 mT,the phenomenon of magnetic bias is very weak.Welding can be done normally.After the welding is completed,the appearance of the weld seam is observed to be good,and the weld seam is free of defects.

关 键 词：焊接电弧 磁偏吹 永磁式流量计 磁屏蔽 磁通密度 焊缝探伤 

分 类 号：TH814[机械工程—仪器科学与技术]