Aluminum welding standards
Aluminum welding standards
Aluminum welding method: almost all kinds of welding methods can be used for welding aluminum and aluminum, but aluminum and aluminum alloy welding method of the adaptability of various different kinds of welding method has its own applications. Gas welding and arc welding methods, equipment is simple, easy to operate. Welding can be used for less demanding on the welding quality of the welding of aluminum sheet and casting. SMAW welding for aluminum alloy castings. Inert gas welding (TIG or MIG) is the most widely used method for welding aluminum and aluminum alloys. Aluminum and aluminum alloy sheet can be tungsten or tungsten AC TIG pulse welding. Aluminum and aluminum alloy plate can be tungsten arc welding of helium, argon-helium mixed gas tungsten arc welding, MIG welding, pulsed MIG welding. MIG welding, pulsed MIG welding is widely applied (argon or argon / helium mixture) for 1 before welding, cleaning before welding: aluminum and aluminum welding, welding should be strictly removed before welding jobs port and wire surface oxide film and oil; 1) Chemical Cleaning Chemical cleaning, high efficiency, stable quality, and size for little clean-up wire, batch production of parts. Soak and scrub the law can be used both methods. Used acetone, gasoline, kerosene and other organic solvents to the oil surface, with 40 ℃ ~ 70 ℃ in 5% ~ 10% NaOH solution Caustic 3 min ~ 7 min (aluminum take longer but not more than 20 min), mobile water rinse and then at room temperature to 60 ℃, 30% HNO3 acid solution 1 min ~ 3 min, mobile wash, dry or cold dry. 2) Mechanical cleaning: large size in the piece, the production cycle is longer, multi-layer welding or chemical cleaning and then stained, usually with mechanical cleaning. First with acetone, gasoline, etc. Wipe the surface with degreasing solvent, and then directly with a diameter of 0.15 mm ~ 0.2 mm of copper wire brush or stainless steel wire brush, brush the exposed metallic luster so far. Generally should not use ordinary sanding wheel or so left on the metal surface sand, welding slag into the molten pool generated defects. There is also available scraper, file and other clean surface to be welded. If stored too long after the clean-up (if more than 24 h) should be reprocessed. 2, plate: aluminum alloy at high temperature, low strength, good flow properties of liquid aluminum in the weld metal welding prone to staying phenomenon. In order to ensure penetration but not collapse, welding often in and around the plate to lift up the metal bath. Plate can be graphite plate, stainless steel, carbon steel, copper or brass rod and so on. Plate to open a circular-shaped surface groove, in order to ensure the weld negative shape. May not add side welding plate forming, but requiring a skilled operator or take strict energy of arc welding automatic feedback control and other advanced technology measures. 3, preheat: thin, small pieces of aluminum generally do not warm up, the thickness of 10 mm ~ 15 mm preheating before welding can be carried out, according to the different types of alloy preheating temperature for 100 ℃ ~ 200 ℃, the oxygen available an acetylene flame, furnace or other heating blowtorch. Preheating can reduce the deformation of the weldment, reducing porosity and other defects. Treatment after welding (1) clean up after welding and after welding to stay in the vicinity of the weld and weld slag and other residual flux will destroy the passive film on aluminum surfaces, and sometimes corrosion of aluminum parts should be cleaned up. Simple shapes, requiring general or workpiece can be washed with hot water, steam blowing easy way to clean brushes, etc.. Demanding and complex shape of the aluminum parts, using a stiff brush in hot water after brushing, and then at about 60 ℃ ~ 80 ℃, the concentration of 2% to 3% of the chromic acid or potassium dichromate solution in the immersion solution 5 min ~ 10 min, and scrubbing with a stiff brush, then wash in hot water washing, drying oven, or hot air drying can also be dry. (2) post weld heat treatment of aluminum containers generally do not require post-weld heat treatment