Sapa Extrusion is the world’s leading aluminum solutions company, but we don’t just offer aluminum products. Sapa provides many post-extrusion operations and value-added fabrication services, including brazing and welding aluminum, for clients in virtually every industrial, commercial and consumer market.
To take advantage of aluminum's full potential in structural applications, the metal must be readily weldable. Before the inert gas welding processes (GTAW & GMAW) were developed, the arc welding of aluminum involved a flux-coated welding electrode, but the end result was often corrosion cause by flux entrapment and excessive porosity.
With the introduction in the 1940s of welding processes that used an inert gas to protect the molten aluminum during welding, it became possible to make high-quality, high-strength welds at high speeds and in all positions, without corrosive fluxes. Aluminum welding methods today include:
Aluminum TIG Welding – Tungsten Inert Gas (TIG) welding, also known as Gas Tungsten Arc Welding (GTAW), is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. This method welds more metals and alloys than any other welding process.
TIG welding was developed in the 1940s, and is still extensively used to successfully weld aluminum alloys today. In fact, many of the highest quality welds used in critical applications are made almost exclusively with this welding process. It is particularly useful for welding thin sections and delicate pieces that require a lighter touch to avoid destroying the integrity of the metal object or sheet.
Alternating current (AC) is used for most applications, but direct current (DC) power is employed for some specialized applications. Argon gas is typically used to protect the weld puddle from contamination, no flux is required, and TIG welding produces fewer sparks, fumes and smoke than other methods. Pure argon is a cost effective gas solution, and helium can be added to increase arc stability.
Aluminum MIG Welding – Metal Inert Gas (MIG) welding, also referred to as Gas Metal Arc Welding (GMAW), is another method used for welding aluminum, and is the most common industrial welding process.
The MIG method uses a continuously feeding spool of wire to burn, melt and fuse the base and parent metals together. The continuously fed wire keeps both hands free for welding, improving the welding speed, quality of the weld, and overall control, and the process can be easily mechanized (robotic welding).
The main difference between the tungsten arc welding process and the MIG process is in the difference of the electrodes. MIG welding is a very versatile process and can weld a wide range of metals and alloys, but the welds are not usually as neat or controlled compared to TIG welds.
FSW Welding – Friction-stir welding (FSW) is a solid-state joining process (meaning the metal is not melted during the process) and is used for applications where the original metal characteristics must remain unchanged as far as possible and weld distortion must be minimized.
FSW involves joining flush metal surfaces through the mechanical action of a rotating tool. With the effects of pressure and heat, a new, homogenous structure is achieved.
Compared with melt welding, FSW provides greater strength and less heat deformation, and reduces the thermal stresses in the material. This makes it possible to weld alloys that are difficult or impossible to weld by fusion welding.
With nearly 40 years of experience in custom aluminum fabrication, Sapa has the expertise to accomplish projects that other shops may turn down. Our welding expertise also includes laser welding, which is capable of welding aluminum to aluminum without any bimetallic effects; ultrasonic welding, which can weld copper tubes to aluminum sheets; and Continuous Step Welding (CSW), a new technology that uses very low amounts of energy and also deforms the tubes to introduce turbulence.
Get in touch with Sapa Extrusions to see how our state-of-the-art solutions can solve your custom design challenges.