In the paper, the effect of beam oscillation frequency on zinc-induced spatter behavior was investigated for remote laser welding of thin-gage zinc-coated steel. The experimental study showed that welding with zigzag beam oscillation of 5 cycles/mm exhibited significantly improved weld aesthetics and less spatter-induced mass loss compared to the baseline condition by conventional straight-line welding. In addition, the weld quality varied with the oscillation frequency. To understand the above-mentioned phenomena, numerical simulations of welding processes by straight line and zigzag oscillations were carried out to study process physics including keyhole opening, zinc evaporation rate, molten pool flow and keyhole wall temperature. It was found that with keyhole penetration mode, variation of keyhole opening exhibited consistent frequency of 135 Hz across welding with the straight line and welding with various beam oscillation frequencies. Welding with beam oscillation frequency larger than the keyhole oscillation of 135 Hz was observed to have a relative stable keyhole and reduced process spatter as long as the frequency is not too high to cause reduced laser energy absorption and inadequate recoil pressure to hold keyhole stable. Further analysis showed that beam oscillation led to a wide and less dense laser energy distribution with low energy gradient, and an adequate oscillation frequency resulted in consistent laser energy input along the feed direction, such as 5 cycles/mm. Together they contributed to large molten pool mass, few hot spots in the laser keyhole rear wall, stable zinc evaporation rate and reduced peak magnitudes of recoil pressure. All these are beneficial to reduction of keyhole opening variation amplitude and prevention of spatter. The application of spatter occurrence measures Z_out and Z_p proposed in our previous work further confirmed the observation that the welding with oscillation frequency higher than the keyhole oscillation frequency has lower possibility of spattering.

在本文中，研究了光束振荡频率对薄规格镀锌钢远程激​​光焊接的锌诱导飞溅行为的影响。实验研究表明，与传统直线焊接的基线条件相比，采用 5 个周期/毫米的锯齿形梁振荡焊接显示出显着改善的焊接美观性和更少的飞溅引起的质量损失。此外，焊接质量随振荡频率而变化。为了解上述现象，对焊接过程进行了直线振荡和锯齿振荡数值模拟，研究了小孔开度、锌蒸发率、熔池流动和小孔壁温等工艺物理过程。结果发现，在钥匙孔穿透模式下，小孔开口的变化在直线焊接和不同光束振荡频率的焊接中表现出一致的 135 Hz 频率。观察到光束振荡频率大于 135 Hz 小孔振荡的焊接具有相对稳定的小孔和减少的工艺飞溅，只要频率不会太高导致激光能量吸收减少和反冲压力不足以保持小孔稳定。进一步的分析表明，光束振荡导致激光能量分布较宽且密度较低，能量梯度较低，足够的振荡频率导致沿进给方向一致的激光能量输入，例如 5 周期/毫米。它们共同导致熔池质量大，激光锁孔后壁的热点很少，稳定的锌蒸发速率和降低的反冲压力峰值。这些都有利于减小锁孔开口变化幅度和防止飞溅。飞溅发生措施的应用在我们之前的工作中提出的Z _out和Z _p进一步证实了一个观察结果，即振荡频率高于小孔振荡频率的焊接具有较低的飞溅可能性。