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激光-双MIG(熔化极稀有气体保护)电弧复合焊具有熔深大、熔敷效率高、焊接质量好等特点,然而由于其耦合机理复杂,给应用带来了一定的困难。基于电磁场理论提出了激光与双电弧耦合机制,当激光光致等离子体中间部位的电子受到两个电弧产生的洛伦兹力和电场力相差较大时,等离子体两端的电子分布会不均匀,这使得一端电弧发生弯曲,沿焊丝轴向的促进力减小,熔滴过渡困难。当激光光致等离子体中间部位的电子受到两个电弧产生的洛伦兹力和电场力大致平衡时,电子能够比较均匀地分布在等离子体的两端,吸引稳定电弧,利于熔滴过渡。采用高速摄影系统和电信号采集系统研究激光-双MIG电弧复合焊接过程,结果表明:当工艺参数不合适时,电弧发生弯曲,导致不稳定的大颗粒过渡和短路过渡;当工艺参数合适时,两个电弧根部被固定在激光光致等离子体的下部,形成稳定的射流过渡。
Laser - double MIG arc welding has the characteristics of large penetration, high deposition efficiency and good welding quality. However, due to its complicated coupling mechanism, it brings some difficulties to the application. Based on the theory of electromagnetic field, the coupling mechanism between laser and double arc is proposed. When the Lorentz force and the electric field force generated by the two arcs are large, the electron distribution at the plasma ends will not be uniform. This makes one end of the arc bending, along the axis of the wire to reduce the promotion of the droplet transfer difficult. When the electrons in the middle part of the laser-induced plasma are roughly balanced by the Lorentz force and the electric field generated by the two electric arcs, the electrons can be distributed more evenly at both ends of the plasma to attract the stable arc and facilitate the droplet transfer. The laser-double MIG arc hybrid welding process was studied by using high-speed photography system and electric signal acquisition system. The results show that when the process parameters are not suitable, the arc is bent, resulting in unstable large particles transition and short circuit transition. When the process parameters are suitable, The two arc roots are fixed to the lower part of the laser photo-plasma, forming a stable jet transition.