Laser Welding Aluminum
The main problems of laser welding of aluminum alloy can be summarized into 6 aspects: weld hole, welding energy coupling, weld formation, stress deformation, joint strength, welding hot crack. When the aluminum alloy is welded by laser, the problems of porosity and heat crack are common. The formation mechanism of stomata is mainly the following: molten hydrogen hole; laser welding is the porosity of hole closure and process instability; and the evaporation of the low melting element causes the stomata. One of the effective measures to reduce the weld porosity of aluminum alloy is to cut off the source of hydrogen during welding, such as to thoroughly remove the oxide layer on the surface of aluminum alloy masterbatch and filler material, to keep the surface of aluminum alloy fully dry and to protect the molten pool surface with inert gases such as AR. The other is to improve the process method. If the laser additional arc heat source welding, reduce the solidification speed of the weld pool of aluminum alloy, so that the gas precipitation.
The absorption rate of aluminum alloy laser welding can be used in the following ways: welding structure design, laser parameter adjustment and proper surface pretreatment process.