旁路耦合微束等离子弧焊熔滴过渡特性分析

Analysis of Droplet Transfer Characteristics in Bypass Double-electrode Micro-plasma Arc Welding

使用高速摄影采集不同旁路电流、送丝速度和离子气流量下旁路耦合微束等离子弧焊的熔滴过渡图像,研究了熔滴过渡过程,并采用静力平衡理论,分析了熔滴所受的主要作用力。结果表明,当焊接总电流一定时,随着旁路电流的增大熔滴过渡频率随之减小,熔滴尺寸随之增大,旁路电弧对熔滴过渡起阻碍作用;其它参数不变的情况下,熔滴过渡频率随送丝速度的增大先增大后减小,随离子气流量的增大而增大。当焊丝在等离子弧边缘熔化时,重力是促进熔滴过渡的主要作用力,且由于斑点力在水平方向上的分力大于电磁力在水平方向上的分力,熔滴呈排斥过渡;当焊丝在等离子弧中心熔化时,等离子流力是促进熔滴过渡的主要作用力。

The droplet transfer pictures during double-electrode micro-plasma arc welding were collected by using the high speed camera under different bypass currents, wire feeding speeds and plasma gas flow rates, and the droplet transfer process was studied. And the main force acting on droplets was analyzed by using Ihe static equilibrium principle. The results show that when the welding current is constant, the droplet transition frequency decreases and the size of the droplet increases with the increase of bypass current. The bypass arc hinders the droplet transfer. With other parameters unchanged, the droplet transition frequency increases ftrstly and then decreases with the increase of wire feeding speed and it increases with the increase of ion gas flow rate. When the wire is melted at the edge of the plasma arc, the gravity is the main force to promote the droplet transfer, and because the force of the speckle force in the horizontal direction is bigger than that of the electromagnetic force in the horizontal direction, the droplet transition shows exclusive transition. When the wire is melted in the center of the plasma arc, the plasma flow force is the main force to promote the droplet transfer.