The Study On Laser Welding Process Of High Strength Aluminum Alloy With Surfactant

The high strength aluminum alloy has the excellent mechanical property, such asthe high strength-to-weight ratio, corrosion resistance, nonmagnetic, good lowtemperature resistance and so on, but because of the high thermal conductivity, laserreflectivity and oxidation of aluminum alloy, the laser welding of high strengthaluminum alloy has many problems.This paper applies the active laser welding to the butt welding of7075aluminumalloy plate with3mm thickness, which is used to study the influence of technologicalparameters on penetration and welding gap, such as laser power, defocusing amount,shielding gas angle, shielding gas flux and so on. The Laser-TIG hybrid welding isapplied to the overlay welding of2219aluminum alloy plate with8mm thickness, andthe surfactant is applied into the hybrid welding to study the influence of surfactant onpenetration and welding process under different technological parameters, such aslaser power, defocusing amount, arc current, pulse frequency of TIG arc and so on.Simultaneous, for the reason that the surfactant will change the Laser-TIG hybridwelding penetration of high strength aluminum alloy, this paper design an experiment oftwo-sheet tungsten to explore the influence of surfactant on flowage of welding pool.Besides, the microstructure and microhardness test for butt weld of Laser-TIGhybrid welding7075aluminum alloy plate with3mm thickness is analyzed. It isfound that the weld joint appears obviously softening phenomenon, and the proportionof fine grained zone, columnar zone, fusion zone and heat affected zone will changeswhen the surfactant is applied to hybrid welding.This paper also discusses some reasons, such as the influence of surfactant on theLaser-TIG hybrid welding of high strength aluminum alloy, the influence of differentshielding gas on active laser welding of high strength aluminum alloy, the influence ofdifferent surfactant and so on.