外加横向磁场对高速GMAW焊缝成形的影响  

Effect of external transverse magnetic field on weld appearance

作　　者：王林[1] 高进强[1] 杨丰兆 

机构地区：[1]山东大学材料液固结构演变及加工教育部重点实验室,济南250061

出　　处：《焊接学报》2016年第10期9-12,129,共4页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(51275276)

摘　　要：对于高速熔化极气体保护焊接(GMAW)过程,当焊接速度超过临界值后,会出现驼峰焊道,焊缝成形变差.研究证明,熔池中动量很大的后向液体流是产生驼峰焊道的主要原因.研发了外加横向磁场发生装置,通过产生的电磁力来抑制后向液体流的动量,从而抑制驼峰焊道的形成.应用特斯拉计测试和考察了工件上磁感应强度大小及分布的影响因素.通过开展焊接工艺试验分析了不同强度的外加磁场作用下的焊缝成形规律.结果表明,外加横向磁场能明显调控熔池流态,有效抑制驼峰焊道和咬边等缺陷,显著改善焊缝成形,提高临界焊接速度.In high speed gas metal arc welding( GMAW)process,severe geometric defects such as humping bead and undercutting will occur if the welding speed exceeds the critical value. The previous experiments had shown that the backward flowing molten jet with high momentum in the weld pool is responsible for the formation of humping bead. In this study,an external tranverse magnetic field generator is developed so that the welding current in the weld pool interacts with the magnetic field to produce an additional EMF pointing toward the front part of weld pool. And the EMF can control the backward flowing molten jet in the weld pool and adjust fluid flow field to suppress the occurrence of the humping bead. Bead-on plate welding experiments were performed and the influences of the exerted magnetic flux density on the weld bead formation,the arc and the fluid flow behavior inside the weld pool were investigated. The mechanism of the suppressing humping bead by the external electromagnetic field was revealed. The results show that the external magnetic field can remarkably adjust the fluid flow field in weld pool and prevent the occurance of the weld defects such as humping bead and undercutting,so the quality of weld bead is remarkably improved,and the critical welding speed is notably increased.

关 键 词：高速GMAW 外加磁场 驼峰焊道 后向液体流 

分 类 号：TG444[金属学及工艺—焊接]