激光-电弧复合焊接是一类稳定、可靠、加工效率高的新型制造技术, 急需在国内工业制造领域进行推广应用。基于标准正交试验设计方法, 分析探讨了4 mm厚5A06高强铝合金光纤激光-MIG电弧复合焊接的表面成形规律与气孔特性。实验结果表明, 工艺参数对试样熔深的影响由大至小依次为焊接速度、电弧焊接参数、离焦量、激光功率、光丝间距。实验参数为焊接速度25 mm/s、离焦量＋2 mm、送丝速度9 m/min、电流123 A、电压23 V、激光功率3 kW、光丝间距3 mm时, 可获得良好的试样表面成形。相比铝合金纯激光填丝焊接, 稳定的光纤激光-MIG电弧复合焊接无需对母材进行精细的氢来源控制和复杂的焊接前后处理, 即可有效地减少甚至完全消除铝合金试样的接头氢气孔。抑制气孔的机理主要从优化熔池流动行为、增强熔池小孔稳定性、降低熔池凝固速率三方面考虑。

Laser-arc hybrid welding is a new kind of manufacturing technology with reliable processing ability and high efficiency which is urgent to be applied in domestic manufacturing industry. In this paper, the surface forming law and porosity features of 4 mm-5A06 high strength aluminum alloy using fiber laser-MIG arc hybrid welding are analyzed based on the standard orthogonal experiments. The experimental results show the degressive influence of processing parameters on the penetration depth of the welding samples, as the order from large to small, which are the welding speed, the defocusing amount、the arc parameters, the laser power, and the laser-arc distance. At the welding speed of 25 mm/s, the defocusing amount of +2 mm, the wire feeding speed of 9m/min, current of 123 A, voltage of 23 V, laser power of 3 kW, fine surface forming qualities of welding samples are obtained. Compared with laser welding of the aluminum alloy with filler wire, the stable laser-MIG arc hybrid welding process could effectively reduce or completely eliminate the porosities of aluminum alloy samples without exquisite control measures of hydrogen input and complicated processing treatment. The mechanism of the porosity inhibition are mainly considered from three aspects which are the changed flowing behavior of molten pool, the stability of the laser keyhole and the reduction of the solidification rate.