航天器用微泵激光焊接气孔形成机理研究

Porosity Formation Mechanism Research in Laser Welding of Micro-pump

为研究微泵激光焊接过程中的气孔形成机理,通过试验分析了激光焊接速度、离焦量、保护气体种类和吹气方式对微泵焊缝气孔率的影响规律。结果表明,随着激光离焦量的增加,焊缝气孔率逐渐降低,当激光离焦量小于+3 mm时,激光焊接模式为深熔焊,焊缝内部存在较多的工艺型气孔和冶金型气孔;激光离焦量大于+5 mm时,激光焊接模式为热导焊,焊缝内部气孔率显著降低。随着焊接速度的提高,气孔上浮速度可能低于熔池凝固速度,导致内部气孔率增加。降低焊接速度、采用N2保护气和采用尾吹吹气方式均有助于降低微泵焊缝气孔率。

This paper investigates the mechanism of pore formation in the micro-pump laser welding process and analyzes the influence of laser welding speed,defocus amount,type of shielding gas,and blowing method on the porosity of micropump weld seams.The research results indicate that as the laser defocus amount increases,the porosity of micro-pump weld seams gradually decreases.When the laser defocus amount is less than+3 mm,the laser welding mode is deep penetration welding,and there are many process-induced pores and metallurgical pores inside the weld seam.When the laser defocus amount is greater than+5 mm,the laser welding mode is heat conduction welding,and the porosity inside the weld seam significantly decreases.Lowering the welding speed,using N2 as the shielding gas,and adopting the trailing blowing method all contribute to reducing the porosity of micro-pump weld seams.