高频交变磁场对大电流GMAW熔滴过渡和飞溅率的影响

在熔化极气体保护焊过程中，采用大送丝速度，增大焊接电流和焊丝伸出长度是提高焊接熔敷率的直接途径.但当熔滴过渡转变为旋转射流过渡时，电弧不稳，飞溅增大，焊缝成形变差.施加不同频率的纵向交变磁场，对焊缝成形进行控制.采用高速摄像技术，拍摄焊接过程中的电弧形态和熔滴过渡，研究不同频率的磁场对熔滴过渡和焊接飞溅率的影响规律.结果表明，熔滴过渡形式不同，产生飞溅的机理不同；外加频率为1 000 Hz纵向交变磁场时，电弧的旋转半径减小，电弧的挺度增大，旋转射流过渡时电弧更稳定，焊接飞溅率降低，焊缝成形改善.

Effect of high frequency longitudinal alternating magnetic field on droplet transfer and spatter rate in high current GMAW welding

In the process of gas shielded arc welding (GMAW), it is a direct way to increase the welding deposit rate by adopting high wire feeding speed, increasing welding current and dry elongation. However, when the droplet transfer is changed into rotating jet transfer, the arc is unstable, the spatter increases and the weld formation becomes worse. A longitudinal alternating magnetic field with different frequencies is applied to control the weld formation. The arc shape and droplet transfer during welding were photographed by high-speed video camera. The effects of magnetic field with different frequencies on droplet transfer and welding spatter rate were studied. The results show that the mechanism of spatter is different with different droplet transfer modes; when the applied frequency is 1 000 Hz longitudinal alternating magnetic field, the rotating radius of arc decreases, the stiffness of arc increases, the arc is more stable, the welding spatter rate decreases, and the weld shape is improved.