FSW (Friction Stir Welding)

Friction Stir Welding (FSW) is being one of the most popular trends in welding technology. FSW is a solid-state process of joining two solid materials, without filler material. The weld is created solely by mechanical string using heat made by friction. This technology is especially suitable for the welding of castings made under high pressure, while other welding processes and their high temperatures cause problems due to voids (porosities).

The process also enables joining materials of two different production technologies (eg. casting and extrusion). Increasing demand to lower down the temperature of electronics by liquid, this method offers a solution for heat-exchangers in the automotive industry.

It also offers solutions in structural parts, its high strength, and fatigue weld behaviour.

Kovolis Hedvikov has been supplying heat exchangers since the year 1996, method of FSW has been tested on a pilot project in 2021, particularly on exchangers for automotive.

This project was successful, tested on the join of castings, but also on the combination of casting and formed products from different materials.


  • Solid-state welding without filler material
  • Welding of different materials
  • Suitable for joining of castings made by HPDC technology
  • Low sensitivity to internal material defects
  • Excellent thermal and electrical conduction
  • High mechanical resistance: weld efficiency of 80-90%
  • Fatigue strength close to the base material
  • No leakage
  • Use in the automotive industry
    • e-mobility, heat exchangers to cool down electronics
    • structural parts with demand for specific mechanical properties

In Kovolis Hedvikov running since 2021 (a pilot project of heat exchanger).