交变纵向磁场作用下MIG焊电弧行为研究

Research on MIG welding arc under alternating longitudinal magnetic field

为了研究交变纵向磁场作用下MIG焊接电弧的物理特性,提高焊接质量,分析了交变纵向磁场作用下电弧带电粒子的受力情况和运动状态,并利用高速摄像手段研究了交变纵向磁场对电弧形态的影响。结果表明,无外加交变纵向磁场时,自由电弧稳定燃烧,电弧轴线与焊丝轴线相重合;当加入交变纵向磁场时,电弧围绕焊丝轴线做逆时针和顺时针交替变化的旋转运动,电弧轴线偏离焊丝轴线;随着励磁电流的增加,电弧的旋转半径增大,电弧偏离焊丝轴线的角度增大,电弧烁亮区域面积减小;当励磁电流为30 A时,电弧的最大偏转角度为45°,此时电弧燃烧变得不稳定,甚至息弧,焊接过程不稳定。

In order to study physical characteristics of MIG welding arc under longitudinal magnetic field and improve welding quality,the stress and motion state of charged particle in the welding arc under longitudinal alternating magnetic field were analyzed,and the impact of longitudinal alternating magnetic field on the arc shape were studied by a high-speed video camera.The results show that the free arc burned stably and arc axis coincided with the welding wire axis without external alternating longitudinal magnetic field.When alternating longitudinal magnetic field was introduced into welding process,the welding arc rotated around the welding wire axis clockwise and counter-clockwise alternately,and arc axis deviated from the welding wire axis.As the exciting current increased,rotating radius of arc increased and arc angle of deviation from the wire axis increased and arc brightness decreased.When the excitation current was 30 A,the large deflection angle of arc was 45°,the arc became unstable combustion,or even arc was extinguished and welding process become unstable.