针对激光深熔焊过程中易出现的气孔问题 ,本文研究了激光焊接时脉冲频率对焊缝气孔倾向及焊缝成形的影响规律。利用自制的斩波盘式激光脉冲调制机构和 3kW快轴流CO₂ 激光器进行了 5mm低碳钢板的激光焊接 ,分析了不同脉冲频率条件下焊缝成形和气孔分布。结果表明 ,厚板连续激光焊接时 ,气孔倾向十分严重 ,在未焊透的焊缝中 ,气孔主要分布在焊缝的根部 ,而采用频率在 15-20Hz范围的脉冲激光焊接 ,能显著减少焊缝中的气孔

Porosity is apt to occur in deep penetration laser beam welding.Repression of porosity sith pulse modulation in CO₂ laser welding was inestigated,A 3 kW fast axial CO₂ laser was used to perform bead-on -plate welding of mild steel,and a chopper device was developed to produce 50% duty ane 0-50Hz frequency pulse laser,The influence of pulse frequency on the weld bead formation and porosith was studied.The experimental results indicate that pulse modulated laser within range of 15-20Hz frequency can significantluy reduce porosity in the weld metal