Friction stir welding also known as FSW means that the metal is
not melted during the process of joining. This is a solid-state
process in which you use a third "body" tool to join two surfaces.
Between the tool and material a lot of heat is created which
results in a soft region in the metal close to the FSW tool.
Friction welding or FRW is also a solid-state welding process
whereby heat is generated through friction between a moving tool
and the component being worked on. A so-called lateral force
"upsets" the materials being joined in such a way as they are
fused. No melt occurs during the process, friction welding is
therefore not really a welding process in the sense of electrode or
gas welding. It is a technique for forging metals together.
Friction welding is commonly used with special metals in the
aviation and the automotive industries.
