高速保护气流向对光纤激光深熔焊接羽辉的影响

Influence of flow direction of high-speed shielding gas on plume in fiber laser deep penetration welding

光纤激光深熔焊接羽辉可分为底部摆动羽辉和类似于激光束聚焦形态的狭长形羽辉.采用6 kW的光纤激光焊接低碳钢,对比研究了旁轴高速保护气流对这两部分羽辉的影响.结果表明,高速保护气流对狭长形羽辉具有明显的抑制效果,但其流向对焊接过程稳定性的影响则明显不同:气流逆焊接方向时飞溅多、熔深浅、焊缝成形差;气流沿焊接方向时飞溅少、熔深加深、焊缝成形良好,保护气流逆焊接方向时,小孔口前部凸起液柱发生偏折,小孔口缩小、熔池波动更剧烈.进一步分析表明,保护气流逆焊接方向时,小孔口前部凸起液柱向小孔口偏折并堵塞小孔、影响底部摆动羽辉的喷发是致使焊接过程稳定性恶化的主要原因.在光纤激光焊接中,布置保护气时应该考虑其流向对底部摆动羽辉喷发状态的影响.

Plume is an inherent physical phenomenon in the process of fiber laser deep penetration welding.The plume consisted of two parts:the oscillating part at the bottom and has a serious negative impact on the laser welding process.At present,the removal method of narrow and long plume is mainly horizontal blowing with supersonic air curtain,but there is no targeted removal method for the swing part at the bottom.In this paper,6 kW fiber laser is used to weld low carbon steel,and the influence of side shaft high-speed protective air flow on these two parts of plume is compared and studied.At the same time,the influence of protective airflow direction on the welding process was studied,the welding process was observed and the weld morphology was analyzed.