焊接工艺对7N01P铝合金激光-MIG复合焊接接头中气孔的影响

铝合金在激光-熔化极惰性气体保护（melt inert-gas，MIG）复合热源焊接过程中形成的气孔会引起应力集中、降低焊接接头的强度和塑性等问题，从而明显降低焊接接头的性能。采用激光-MIG复合热源焊接技术，对4 mm厚7N01P铝合金进行了对接焊接，分析了焊接工艺对焊接接头中气孔的影响。结果表明，采用复合热源焊接技术，在送丝速度为7.0、8.0、9.0 m/min，焊接速度为0.9、1.0、1.1 m/min，功率分别为2.3、2.4、2.5 kW时均可以实现7N01P 铝合金板材的单面焊双面成形。当激光功率为2.3 kW，送丝速度为9.0 m/min，焊接速度为1.0 m/min时，焊接接头中的气孔数量最少，气孔率约为1.2%。此外，激光功率的变化会影响焊接接头中气孔的形成，随着激光功率从2.3 kW增加到2.5 kW时，气孔数量先增加后下降；送丝速度的变化也会影响焊接接头中气孔数量，当送丝速度由7.0 m/min增加至9.0 m/min时，气孔数量有所降低；而焊接速度对焊接接头中气孔的影响是双向的，随着焊接速度的增加，气孔数量先减少（焊接速度从0.9 m/min到1.0 m/min）后增加（焊接速度在1.1 m/min）。可见，工艺参数的优化可以起到减少焊接接头中气孔的作用。

Influence of Welding Process on the Porosity of Laser-MIG Hybrid Welded 7N01P Aluminum Alloy Joint

The porosity of aluminum alloy formed in the process of laser melt inert-gas (MIG) hybrid heat source welding will cause stress concentration, reduction of strength and plasticity of the welded joint, and other problems, thus the performance of the welded joint is significantly decreased. The butt welding of 4 mm thick 7N01P aluminum alloy was carried out by using laser MIG hybrid heat source welding technology, and the influence of welding process on the porosity in the welding joint was analyzed. The results show that when the wire feeding speed is 7.0, 8.0 and 9.0 m/min, the welding speed is 0.9, 1.0 and 1.1 m/min, and the power is 2.3, 2.4 and 2.5 kW, the single side welding double side forming of 7N01P aluminum alloy sheet can be realized. In addition, the change of laser power will affect the formation of pores in the welded joint. With the laser power increased of from 2.3 kW to 2.5 kW, the number of pores first increases and then decreases. The change of wire feeding speed will also affect the number of pores in the welded joint. When the wire feeding speed is increased from 7.0 m/min to 9.0 m/min, the number of pores decreases. However, the effect of welding speed on porosity is bidirectional. With the increase of welding speed, the number of pores first decreases (welding speed from 0.9 m/min to 1.0 m/min) and then increases (welding speed at 1.1 m/min). It can be seen that the optimization of process parameters shows an effect of reducing the porosity in the welded joint.