外加纵向磁场对CO_2焊接短路液桥的影响

为了减少CO_2焊接飞溅,利用高速摄像装置拍摄外加纵向磁场作用下CO_2焊熔滴过渡过程,对液桥形成段、液桥缩颈段进行了研究.结果表明,当施加低频磁场时,随着磁场频率的增加,熔滴半径随之增大并在磁场频率为60 Hz时达到最大值,此时球状熔滴的体积最大;随着磁场频率的增加,液桥形成段缩短,促进了短路初期的熔滴过渡过程.当施加高频磁场时,液桥缩颈段赤道面的最小半径减小,促进了短路末期的熔滴过渡过程.外加纵向磁场可以有效促进熔滴的短路过渡过程,从而减小CO_2焊接飞溅.

Influence of external longitudinal magnetic field on short circuit liquid bridge of CO2 welding

In order to reduce CO₂ welding spatter, the droplet transfer process of CO₂ welding under the action of external longitudinal magnetic field was shot with high-speed camera, and the formation stage and shrinking period of liquid bridge were investigated. The results show that when the low frequency magnetic field is imposed, with increasing the magnetic field frequency, the droplet radius increases, reaches the maximum value at the magnetic field frequency of 60 Hz, and has the largest globular droplet volume at this time. With increasing the magnetic field frequency, the formation period of liquid bridge shortens, and the droplet transfer process at the early stage of short circuit is promoted. When the high frequency magnetic field is imposed, the minimum radius of equatorial plane in the shrinking period of liquid bridge reduces, and the droplet transfer process at the terminal stage of short circuit is promoted. The external longitudinal magnetic field can effectively promote the short circuit transfer of droplet, and thus can reduce the CO₂ welding spatter.