Friction Stir Welding: The New Frontier in Welding
In 1991, an elegant new way to weld metals revolutionized the world. The process known as friction stir welding (FSW) moved welding out of the Stone Age and into the technology age, allowing precise, mess-free welding.
Friction stir welding is a solid-state joining process where a rotating and traversing FSW tool generates sufficient frictional heat along a joint between two metals to form a weld. It can be considered a “green” approach to joining since an external heating source is not needed and is more environmentally friendly than other methods since neither a flux nor a shielding gas are required.
There are several strength, speed, consumption, and cost benefits associated with friction stir welding. Many of these advantages are due to the fact that there is no microscopic melting during FSW, so the process is free of problems associated with traditional welding, such as porosity, lack of fusion, and change in material.
In this blog, we will discuss a remarkable benefit also associated with FSW: the ability to weld dissimilar aluminum alloys.
Welding of Dissimilar Alloys
Industries such as aerospace, military, transportation, manufacturing, and cargo ship production have a pressing need for welding dissimilar metals. Welding, instead of riveting, joints can produce significant cost savings while reducing the weight of their vessels or constructions.
However, the welding of dissimilar alloys poses quite a conundrum. The different chemical and physical properties of dissimilar alloys can cause havoc as metals flow into each other during a conventional welding process.
FSW’s ability for welding dissimilar aluminum alloys at an industrial level is aided by being a solid-state welding technique.
The Future of Friction Stir Welding and Dissimilar Alloys
Despite FSW’s success with aluminum, not every combination of metals can currently be welded by FSW, including some aluminum alloys. The formation of intermetallic compounds lowers weld quality.
Monumental efforts in research and development are being applied to the achievement of these FSW goals. This involves a lot of trial and error with spin speed, spin head and pin materials, and joint configurations.
Other options, such as submerged friction stir welding — submerging or having water run over the welding zone — might solve common problems associated with dissimilar welding alloys. The water helps extract heat from the joint, decreasing grain size and increasing tensile strength.
In other research areas, techniques such as friction stir knead welding have been used successfully to weld together very thin aluminum sheets with steel. The distinguishing feature of this variant of FSW is that it does not use the pin portion of the rotating tool.
Taber continues to extrude billet in a wide range of alloys and sizes and has diversified its markets beyond military since its inception to include aerospace, automotive, marine, infrastructure, and sporting goods, among many others. With in-house casting solutions, ultra-precision extrusion manufacturing, friction stir welding capacities, and a full range of hard and soft aluminum alloys, Taber continues to align itself as an industry leader in having the broadest available capabilities.
Today, Taber Extrusions is proud of its recently added VF-12 CNC machining line and a full offering of extruded aluminum components, value-added machining services, and raw material supply to the North American market. Adding these capabilities to a growing portfolio propels Taber into the future in a quest to continuously improve the quality and service we provide to our customers.