Friction Stir Welding (FSW)

State-of-the-art joining process for a variety of applications

FSW - Welding the unweldable

Friction Stir Welding (FSW) is a solid-state welding process which is used in various industries, such as aerospace, automotive, and shipbuilding. 

A wear-resistant rotating tool is plunged into the joining surface of the join partners and is subsequently traversed along the weld line. During cooling, an appropriate weld seam is produced between the respective components. The stirring process is done by a non-consumable rotating tool.

The shoulder of the tool applies force to the top of the material. The friction between the rotating shoulder of the tool and the material generates the heat input which plasticizes the material. The tool traverses the joint line, the plasticized material cools down and is forming a metallurgical joint.

Friction stir welding can be principally applied to all materials which can be plasticized. The joining process, however, is particularly suitable for welding aluminum in all alloy and manufacturing forms for thicknesses from 0.5mm up to over 50mm. Apart from that, the process enables the joining of different (dissimilar) materials. For friction stir welding of aluminum alloys, the globally valid standard DIN EN ISO 25239 – Part 1-5 can be applied.

Advantages of Friction Stir Welding (FSW)

The advantages of Friction Stir Welding

  • High Joint Strength
    FSW produces welds with excellent mechanical properties, due to no solidification and a forged, fine-grained microstructure.
  • Minimal distortion
    FSW operates at lower temperatures and low heat input compared to fusion welding, welded components have a reduced distortion and residual stress levels, ideal for welded parts with tight tolerances.
  • Excellent fatigue behavior
    FSW generates a fine-grained forged microstructure in the joint line, which lead to excellent fatigue properties.
  • Joining dissimilar materials
    FSW can join dissimilar materials due to the low heat input high forcing action, including different aluminum alloys, like wrought aluminum to aluminum cast or aluminum to steel or copper, and even advanced composites.
  • Environmentally friendly
    FSW produces no fumes, gases, or radiation; no protective gas, additional material or preparation of the joining edges required.
  • Automatization
    easy to automate and monitor because it´s a mechanic mixing process.

The disadvantage is the remaining exit hole, the high forces during the welding process, require a rigid machine and a tight clamp.

Weldable Materials – Friction Sir Welding

Weldable Materials

  • Aluminum in all different alloy groups
  • Aluminum of different manufacturing processes (e.g.cast and wrought alloys)
  • Aluminum / Copper
  • Aluminum / Steel
  • Aluminum / Magnesium
  • Copper / Steel
  • Thermoplastics

Applications for Friction Stir Welding (FSW)



The cooling circuits of battery trays, stator housings, and inverter housings in electric vehicles are sealed watertight using Stirtec's FSW machines. Stirtec's FSW machines are excellently suited for manufacturing battery trays due to their high welding quality. 
HV Inverter Housings
Electronic Motor Housings
EV / PHEV Battery Trays
Find out more about E-Mobility
Dominik Kaineder

Your contact person: Dominik Kaineder

Are you interested in determining the feasibility of a new concept using Friction Stir Welding? Or do you require assistance in choosing the most-sufficient system for serial production for your application?
Please contact us directly - we'll gladly provide guidance and support.
+43 676 30 93 922