How to weld two aluminum sheets seamlessly
Before aluminum alloy welding, the oxide film and oil stain on the surface of the welding port and welding wire of the workpiece should be carefully removed before welding. Under the action of air and oxygen, a thin and dense natural oxide film is formed on the surface of the aluminum plate, which is more oxidized than other metals. The film is formed quickly and is much thicker, thereby preventing further corrosion of harmful gases and moisture in the air, protecting the aluminum plate, but affecting the welding of the aluminum plate, eradicating the quality directly affects the welding process and quality of joints, such as the trend and mechanics of weld pores performance. Chemical cleaning and mechanical finishing are commonly used in two ways.
1) Chemical cleaning. High chemical cleaning efficiency and stable quality, suitable for finishing welding wires and small-scale, mass-produced workpieces. There are two types of dipping method and scrubbing method. Oil stains can be found in organic solvents such as gasoline. Wash with 5 percent 10 percent NaOH solution at 40 degree 70 degree for 3 min7 min, rinse with active water, and then pickle with 30 percent HNO3 solution at room temperature to 60 degree for 1 min3 min , rinse with active water, air dry or dry at low temperature.
2) When the workpiece is large in scale, long in production cycle, multi-layer welding or chemical cleaning and then dyeing, mechanical finishing is often selected. First wipe the surface with organic solvents such as gasoline to remove oil stains, and then brush directly with a copper wire brush or stainless steel wire brush with a diameter of 0.15mm to 0.2mm until the metallic luster is exposed. Usually, it is not suitable to use a grinding wheel or general sandpaper for grinding, so as to avoid the defects such as sand grains on the metal surface and welding into the slag pool. Alternatively, a scraper, file, etc. can be used to organize the appearance to be welded.