激光功率对铝合金激光-MIG复合焊熔滴过渡行为及飞溅的影响

Influence of Laser Power on Droplet Transfer Behavior and Spatter in Laser-MIG Hybrid Welding of Aluminum Alloy

为研究激光功率对铝合金激光-MIG复合焊接过程稳定性的影响,采用高速摄像及NI USB-6251数据采集卡对复合焊接过程中电弧参数、熔滴过渡行为及飞溅产生行为进行了研究。结果表明:随着激光功率增大,电弧峰值电流减小,而峰值电压增大;在4 kW激光功率时,以射滴过渡为主,偶尔发生短路过渡情况,随激光功率小幅增加,短路过渡现象消失;当激光功率增大到5.5 kW时,稳定的一脉一滴过渡中出现了两脉一滴的过渡形式,降低了熔滴过渡稳定性。激光功率增大,金属蒸气对匙孔壁上液态金属剪切力也随之增强,导致匙孔壁上方飞溅产生次数增加。当激光功率为4~4.5 kW时,匙孔后壁飞溅产生次数明显多于匙孔前壁,但激光功率大于5 kW后,匙孔前后壁飞溅次数相当。最后,对匙孔前后壁熔池金属进行了受力分析,并总结了匙孔壁上方飞溅产生的机理。

To examine the influence of laser power on the stability of laserMIG hybrid aluminum alloy welding process,a highspeed camera and NI USB6251 data acquisition card were used to study the arc parameters,droplet transfer behavior,and spatter generation behavior in the hybrid welding process.The results indicated that as the laser power increased,the peak current of the arc decreased,whereas the peak voltage increased.Under the laser power of 4 kW,the projected droplet transfer was dominant,and shortcircuit transition occurred occasionally.When the laser power increased slightly,the shortcircuit transition phenomenon disappeared.However,when the laser power increased to 5.5 kW,there was a transition form of one droplet every two pulses in the stable transition of one drop per pulse,reducing the stability of the droplet transition.As the laser power increased,the metal vapor shearing force on the liquid metal on the keyhole wall increased,resulting in an increased number of spatters above the keyhole wall.When the laser power was 4‒4.5 kW,the number of spatters on the rear keyhole wall was significantly higher than that on the front keyhole wall.However,when the laser power was more than 5 kW,the number of spatters on the front and back keyhole walls was almost equivalent.In addition,the force of the molten pool metal on the keyhole walls was analyzed,and the mechanism of spatters above the keyhole wall was summarized.