不同CMT工艺2014-T6焊缝成形及气孔分析

分别采用3种不同的冷金属过渡(CMT)焊接工艺进行2014-T6铝合金平板堆焊成形,研究不同CMT工艺对铝合金焊缝成形特征及气孔的影响. 结果表明,保持送丝速度7.5 m/min、电弧长度和保护气体纯Ar流量25L/min不变,2014-T6铝合金常规CMT焊缝具有明显的指状熔深特征,焊缝气孔缺陷严重且呈全焊缝分布特征;脉冲CMT(CMT-P)焊缝的指状熔深特征减缓,气孔显著减少,焊接速度0.6 m/min时焊缝基本无气孔;变极性复合脉冲CMT(CMT-PADV)焊缝熔深仅约0.4 mm,成形呈显著球形特征,气孔明显减少,焊接速度0.4 m/min时基本无气孔.

Weld formation and porosity of 2014-T6 aluminum alloy welds produced by cold metal transfer process

The weld formation and porosity characteristics of 2014-T6 aluminum alloy using three different cold metal transfer welding processes were investigated. Experimental results show that, with constant wire feed speed of 7.5 m/min, contact tip to work distance of 15 mm and pure argon shielding gas flow rate of 25 L/min, finger-shape penetration is observed using the conventional CMT process and there are many gas pores in the lower and upper part of the weld. The volume of the finger-shape weld metal is decreased and the gas pore is reduced significantly using the pulsed CMT process. The porosity is almost eliminated using the welding speed of 0.6 m/min. Spherical-shape weld is achieved using the CMT welding process. The gas pore is also significantly reduced and drop to zero with the welding speed of 0.4 m/min.