Spot pressure, as an arc repelling force, hinders the metal transfer process and has a negative effect on welding process stability in CO₂ gas shielded welding. In addition, the direction of the spot pressure changes uncontrollably with the deflection of the droplet. Therefore, it is particularly critical to provide an additional force to improve droplet transfer characteristics without disturbing the arc stability. To this end, a new approach of the pulsed laser enhanced metal transfer (PLE-MT) process in CO₂ gas shielded welding was proposed to control metal transfer behavior. The results demonstrate that: different from the uncontrollable deflection of droplets caused by laser incident on the solid–liquid interface (S-L-I) of the droplet, the irradiation of solid-state welding wire (S-W) can fundamentally solve the droplet deflection problem. The cut droplet can enter into the molten pool smoothly along the axis, and the change of the incident height does not significantly change the droplet's detachment velocity. The droplet’s detachment time at three different laser incident heights (0.5, 1, and 1.5 mm) remained almost unchanged, all of which were about 6–8 ms. When the wire feeding speed is 4 m/min and the voltage is 25 V, after laser irradiation is added, the metal transfer frequency increases from 5 to 25 Hz. The droplet transfer mode changes from SC transfer to spray transfer, and it avoids the short-circuit spatter. However, the metal evaporation mass produced by laser heating liquid droplet or welding wires is about 3.5% of the droplet mass. Under the condition of direct current electrode negative (DCEN), although the melting efficiency of the wire can be effectively improved, the droplet will be repelled until the arc is extinguished, and the stability of the arc will also deteriorate due to the rise of the arc. The irradiation of the pulsed laser can impede the climb of the droplet (cut off the droplet when its size is small before the arc climbs up), promote metal transfer, and improve the stability of the welding process in DCEN. While expanding the process interval of CO₂ welding, an efficient spatter-free, low-pollution metal transfer process was obtained under a relatively small current through the PLE-CO₂ welding process.

中文翻译：

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CO2气体保护焊中脉冲激光增强金属转移行为的过程控制

点压作为一种电弧排斥力，会阻碍金属转移过程，并对 CO ₂气体保护焊的焊接过程稳定性产生负面影响。此外，点压力的方向随着液滴的偏转而不受控制地变化。因此，在不干扰电弧稳定性的情况下提供额外的力以改善熔滴转移特性尤为关键。为此，脉冲激光增强金属转移 (PLE-MT) 工艺在 CO _{2 中}的新方法提出了气体保护焊来控制金属转移行为。结果表明：与激光入射在液滴的固液界面（SLI）上导致液滴不可控偏转不同，固态焊丝（SW）的辐照可以从根本上解决液滴偏转问题。切割后的液滴可以沿轴线顺利进入熔池，入射高度的变化不会显着改变液滴的脱离速度。液滴在三种不同激光入射高度（0.5、1 和 1.5 毫米）下的脱离时间几乎保持不变，所有这些都约为 6-8 毫秒。当送丝速度为4m/min，电压为25V时，加入激光照射后，金属转移频率从5Hz增加到25Hz。液滴传输方式由SC传输变为喷雾传输，避免了短路飞溅。然而，通过激光加热液滴或焊丝产生的金属蒸发质量为液滴质量的约3.5％。在直流电极负极（DCEN）条件下，虽然可以有效提高焊丝的熔化效率，但熔滴会被排斥直至电弧熄灭，电弧的稳定性也会因电压的升高而恶化。弧。脉冲激光的照射可阻止熔滴的爬升（在电弧爬升前将熔滴尺寸较小时切断熔滴），促进金属转移，提高DCEN焊接过程的稳定性。在扩大CO的处理间隔的同时 并且避免了短路飞溅。然而，激光加热液滴或焊丝产生的金属蒸发质量约为液滴质量的3.5%。在直流电极负极（DCEN）条件下，虽然可以有效提高焊丝的熔化效率，但熔滴会被排斥直至电弧熄灭，电弧的稳定性也会因电压的升高而恶化。弧。脉冲激光的照射可阻止熔滴的爬升（在电弧爬升前将熔滴尺寸较小时切断熔滴），促进金属转移，提高DCEN焊接过程的稳定性。同时扩大CO的工艺间隔 并且避免了短路飞溅。然而，激光加热液滴或焊丝产生的金属蒸发质量约为液滴质量的3.5%。在直流电极负极（DCEN）条件下，虽然可以有效提高焊丝的熔化效率，但熔滴会被排斥直至电弧熄灭，电弧的稳定性也会因电压的升高而恶化。弧。脉冲激光的照射可阻止熔滴的爬升（在电弧爬升前将熔滴尺寸较小时切断熔滴），促进金属转移，提高DCEN焊接过程的稳定性。同时扩大CO的工艺间隔 在直流电极负极（DCEN）条件下，虽然可以有效提高焊丝的熔化效率，但熔滴会被排斥直至电弧熄灭，电弧的稳定性也会因电压的升高而恶化。弧。脉冲激光的照射可阻止液滴的爬升（在电弧爬升之前，当液滴的尺寸较小时将其切断），促进金属转移，并提高DCEN中焊接过程的稳定性。同时扩大CO的工艺间隔 在直流电极负极（DCEN）条件下，虽然可以有效提高焊丝的熔化效率，但熔滴会被排斥直至电弧熄灭，电弧的稳定性也会因电压的升高而恶化。弧。脉冲激光的照射可阻止熔滴的爬升（在电弧爬升前将熔滴尺寸较小时切断熔滴），促进金属转移，提高DCEN焊接过程的稳定性。同时扩大CO的工艺间隔 脉冲激光的照射可阻止液滴的爬升（在电弧爬升之前，当液滴的尺寸较小时将其切断），促进金属转移，并提高DCEN中焊接过程的稳定性。同时扩大CO的工艺间隔 脉冲激光的照射可阻止熔滴的爬升（在电弧爬升前将熔滴尺寸较小时切断熔滴），促进金属转移，提高DCEN焊接过程的稳定性。同时扩大CO的工艺间隔₂焊接，通过 PLE-CO ₂焊接工艺在相对较小的电流下获得了有效的无飞溅、低污染的金属转移工艺。