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Friction stir welding (FSW)

Sapa has led the R&D efforts in the field of friction stir welding (FSW) since the beginning. Using FSW, Sapa can join profiles into panels up to three meters in width, and lengths in accordance with customer requirements.

FSW is a technique that joins flush metal surfaces through the mechanical action of a rotating tool. With the effects of pressure and heat, a new, homogenous structure is achieved.

Compared with fusion welding, FSW provides better properties and less heat deformation. FSW is an established technique – Sapa’s series production started in 1996.

Besides conducting R&D work in the area of FSW tooling and process development, we are involved in characterizing FSW processes and examining weld properties, as well as non-destructive testing methods for quality assessment of friction stir welds.

We monitor worldwide development trends, communicate relevant information to internal FSW users, and support in the development of an ISO standard for FSW.


Our FSW lab is equipped with a powerful, yet accurate, MTS I-STIR process development system, capable of welding any aluminium grade from 1 mm to 30 mm thick. The system supports conventional, adjustable pin and self reacting (bobbin) welding modes. The MTS I-STIR system is fully instrumented to measure and record all important process parameters.

We also use a retrofitted five-axis milling machine for complex path welding.

In-house IWE (International Welding Engineer) competence allows us to qualify production processes and personnel for FSW and arc welding methods.

We offer support to Sapa’s FSW users on:

  • Development of FSW tools and processes
  • Analysis and testing of different joining methods MIG, TIG, friction welding, fastening. Development of FSW tools and process parameters
  • Characterization of processes
  • Investigation of weld properties and examination of weld quality
  • Qualification of processes and personnel
  • Short consultations and troubleshooting