Friction welding has been industrially exploited for over four decades and there are numerous examples of its successful use in reclamation and repair. For instance, plugging the leaking boiler tubes of a CEGB (UK Central Electricity Generating Board) power plant unit. For this application, TWI developed a specialised method of friction taper plug welding and then the CEGB built a machine to carry out the repairs remotely.
Reclamation of a damaged electric motor shaft is another example. In this case, the damaged portion was removed and a new section friction welded directly to the end of the shaft - without having to remove the armature windings. This proved to be a very straightforward and inexpensive repair.
A further example is the attachment of sacrificial anodes to offshore structures, above and below water. For this, a portable friction stud welding machine was used to 'electrically' attach the aluminium alloy-based anodes.
Lockheed Martin Space Systems have used friction taper stitch and friction stir welding to repair weld defects in the external fuel tank used to launch the space shuttle. The tank is made from a weight-saving aluminium-lithium alloy. See reference below.
FAQ: What is friction stitch welding?
(explains friction taper plug welding)
'Friction plug weld repair of space shuttle external tank', Welding and Metal Fabrication, September 2000, vol.68, no.8, pp.6-8.
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