CO2激光-MAG电弧复合焊接过程中熔滴受力及过渡特征研究

以5.0mm高强钢板为试验材料,进行了CO2激光与金属活性气体(MAG)电弧复合焊接试验。通过高速摄像和熔滴的受力分析研究了激光能量、电弧能量、光丝间距对复合焊接过程中熔滴过渡特征的影响。结果表明,激光的加入稳定了电弧,降低了射滴过渡的临界焊接电流值,由于激光对电弧的引导和压缩作用,改变了熔滴内电流线分布及电磁收缩力的大小及方向,进而影响了熔滴过渡特征。同时激光匙孔中喷射出大量的金属蒸气产生反作用力,改变了熔滴原来的受力状态,使熔滴过渡模式发生改变。随着焊接电流的增加,电弧变得更加稳定,能量更加集中,等离子体流力成为熔滴过渡的主导力。光丝间距的大小影响了熔滴过渡的频率,在光丝间距为4mm时熔滴频率最大。

Research on Force State and Transfer Characteristics of Droplets in CO2-MAG Hybrid Welding Process

A CO2 laser-metal active gas(MAG) hybrid welding is used to weld the high strength steel of 5.0 mm thickness.Droplet transfer is observed with high speed camera and the forces on droplet are investigated in detail.The droplet transfer is strongly affected by laser power,arc power and the distance between laser and arc.The results indicate that laser could make arc plasma more stable and decrease the critical current of spray transfer for its leading and constricting felnctions on the arc by the laser.There are changes in the current distribution within droplet and the magnitude and direction of electromagnetic force.At the same time,a large number of metal gas from the keyhole makes a metal steam reaction,changing the force state of the droplet so that the droplet transfer mode is changed.With the increase of the welding current,the arc becomes more stable and the power of arc is more concentrated,making the plasma drag force decisive.The distance between laser and arc has an effect on the frequency of the droplet transfer.When the distance is 4 mm,the frequency of the droplet transfer is the maximum.