Friction welding is a class of solid-state welding processes that generates heat through mechanical friction between a moving workpiece and a stationary component, with the addition of a lateral force called "upset" to plastically displace and fuse the materials.
Technically, because no melt occurs, friction welding is not actually a welding process in the traditional sense, but a forging technique. However, due to the similarities between these techniques and traditional welding, the term has become common. Friction welding is used with metals and thermoplastics in a wide variety of aviation and automotive applications.
Friction Welding Video
Advantages
Dissimilar metals can often be easily joined, even some considered incompatible or unweldable.
The Friction Welding process is at least twice - and up to 100 times - as fast as other welding techniques.
Friction welders are versatile enough to join a wide range of part shapes, materials and sizes.
Joint preparation isn't critical... machined, saw cut, and even sheared surfaces are weldable.
Resulting joints are of forged quality, with a 100% butt joint weld through the contact area.
Since there is no melting, no solidification defects occur, e.g. gas porosity, segregation or slag inclusions.
Powder metal components can be welded to other powder metals, forgings, castings or wrought material.
No consumables required - no flux, filler, or shielding gases required.
The machine - controlled process eliminates human error, and weld quality is independent of operator skill or attitude.
It's ecologically clean - no objectionable smoke, fumes, or gases are generated that need to be exhausted.
No weld spatter and few sparks produced.
Power requirements are as low as 20% of that required of conventional welding processes.
No special foundations or power supplies are needed.
Process parameters easily monitored.
Friction Welding equipment is easily automated for high production rates.
Pre-calculable parameters for most materials and geometry. The process can, therefore, be mathematically scaled (i.e. small samples can be used for large parts development).