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What is Linear Friction Welding?


Linear friction welding involves moving one component in a linear reciprocating motion, through a small amplitude at a suitable frequency, across the face of the second, rigidly clamped component (see illustration).

Reciprocation is maintained until adequate heat and metal flow has taken place, then the moving part is brought into alignment while the axial load is maintained or increased to finalise the weld sequence.

Linear motion normally produces a sinusoidal velocity profile changing from zero to maximum in one direction, then repeating in the opposite direction. However, other velocity profiles are possible on TWI's 'Linfric' machine.

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.

Linear friction welding is most suited to rectangular and irregular cross-sections and is used in complex parts with a number of weld sites and multiple parts, e.g. welding blades to discs in aero-engines and for additive manufacture of components.

Materials which can be welded with this process include carbon-manganese and stainless steels, aluminium, nickel alloys and titanium. In principle, any material which can be rotary friction welded can be linear friction welded.

For further information please see Joining Technologies or contact us.

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