Taking pipe welding as an example, radial friction welding involves rotation and radial compression of a solid bevelled ring into a V-preparation provided by the pipe ends (see illustration).
The pipe ends are butted together and clamped securely to stop them rotating or moving apart. A mandrel is located in the bore, at the weld location, to prevent collapse of the pipe ends and penetration of upset metal formed during the weld sequence.
The ring, made from a compatible material, is more sharply bevelled than the pipes to promote metal flow from the base of the weld preparation. This also reduces the initial torque demand normally associated with the start of the friction cycle, when cold surfaces come into contact.
As with other friction welding processes, no additional filler material is used and welding takes place in the solid phase, i.e. no macroscopic melting is observed.
Radial friction welding has also been demonstrated for attaching ductile bands to projectiles and producing wear resistant surfaces on shafts.
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