Английский для сварщиков. Гричин С.В. - 91 стр.

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Text 1. Friction Stir Welding (FSW)

H.H. Bhadeshia

Friction stir welding, a process invented at TWI, Cambridge in 1991,

involves the joining of metals without fusion or filler materials. It is used

already in routine, as well as critical applications, for the joining of structural

components made of aluminium and its alloys. Indeed, it has been

convincingly demonstrated that the process results in strong and ductile

joints, sometimes in systems which have proved difficult using conventional

welding techniques. The process is most suitable for components which are

flat and long (plates and sheets) but can be adapted for pipes, hollow sections

and positional welding. The welds are created by the combined action of

frictional heating and mechanical deformation due to a rotating tool. The

maximum temperature reached is of the order of 0.8 of the melting

temperature.

The tool has a circular section except at the end where there is a

threaded probe or more complicated flute; the junction between the

cylindrical portion and the probe is known as the shoulder. The probe

penetrates the work piece whereas the shoulder rubs with the top surface. The

heat is generated primarily by friction between a rotating-translating tool, the

shoulder of which rubs against the work piece. There is a volumetric

contribution to heat generation from the adiabatic heating due to

deformation near the pin. The welding parameters have to be adjusted so that