Aluminum TIG Welding
There are many processes that can join aluminum, but, in thin metal, the most visually appealing and mechanically strong process is aluminum TIG welding, also known as Gas Tungsten Arc Welding (GTAW).
The TIG process is similar to welding with an oxy-acetylene torch - with the torch in one hand and the other hand feeding a filler rod. In order to create clean connections, a shielding gas (argon or helium) is used in the surrounding area. It is most often used to weld lightweight metals that need a lighter touch to avoid destroying the integrity of the metal object or sheet.
The gas-shielded arc welding process developed slowly during the late 19th and early 20th centuries and continues to develop today. In 1941, Russell Meredith of Northrop Aircraft perfected the process, using a tungsten electrode arc and an inert gas (helium) as a shielding gas, for the purpose of welding light weight materials. His welding process was originally called Heliarc.
The electrode was prone to overheating, however, and the buildup of heat could not be controlled until alternating current units were developed. Further improvements were made through the decades and, today, there are a variety of useful methods, including tot wire, dabber, and pulsed-current TIG welding.
Advantages of TIG Welding
•Welds more metals and alloys than any other process
•Provides precise, high quality welds
•Ideal for cosmetic welds
•Superior arc and weld puddle control
•Especially good for welding thin sections and delicate pieces
•Produces fewer sparks, fumes and smoke unless the base metal being welded contains contaminants or elements such as, oil, grease, paint, lead or zinc
•Argon gas protects the weld puddle from contamination, so no flux is required, making cleanup easy
•No slag to block the view of the weld puddle
•Filler material is not required
•Offers greater control over welds
•Welds can be made in all positions - flat, horizontal, vertical or overhead
Disadvantages of TIG Welding
•Requires good hand-to-eye coordination
•Is more complex than MIG welding
•More expensive and slower than MIG welding, particularly in thicker metals
Challenges Unique to Welding Aluminum
Aluminum and its alloys are easily weldable; however, there are several issues unique to aluminum that must be considered, such as:
1.Aluminum’s excellent thermal conductivity means that the heat for melting it has to be more intense than the heat needed to melt steel.
2.Aluminum’s high electrical conductivity (only one-third less than copper) means that it won’t change color when heated and will appear to be cold. This requires extra care so as not to touch hot metal.
3.Aluminum’s thin coating of naturally occurring oxide prevents corrosion, but has to be removed before welding to avoid fusion due to its high melting point. It’s also very porous and easily traps moisture, oil, grease and other materials.
4.Aluminum’s non-magnetic properties make magnetic lifting devices ineffective.
After welding, heat treatable alloys can be heated to restore strength lost during welding. Cold working or strain hardening can increase the strength in non-heat treatable alloys.
Sapa Extrusions is the world’s leading soft alloy aluminum extruder. We offer the industry’s broadest product capabilities in press sizes and tonnages (direct and indirect extrusion), alloy selection, circle sizes, profile types and “green” billet.”
In addition, we provide a comprehensive suite of services for clients in virtually all commercial, industrial and consumer markets. We have extensive experience in joining technologies, including aluminum TIG welding, MIG welding, and Friction Stir welding (FSW), and can satisfy your most challenging requirements.