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

Friction Stir Welding

The FSW-technology

Friction Stir Welding (FSW) is a solid-state joining method, i.e. the welding process is performed below the materials melting temperature in the solid state.


Functional principle
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.
Friction stir welding can be principally applied to all materials which can be plasticized. The joining process, however, is particularly suitable for welding aluminium 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 aluminium alloys, the globally valid standard DIN EN ISO 25239 – Part 1-5 can be applied.

FSW of steel

Basically, the technological advantages of friction stir welding can be expanded to materials with high melting points as well. One important aspect of FSW is its applicability for joining of higher-strength steels, since the use of conventional welding methods such as arc welding is limited. The Stirtec-solution is based on the application of FSW-tools that are characterized by a high process reliability at comparatively low tool costs.

Friction Stir Spot Welding

The RFSSW technology


The Refill Friction Stir Spot Welding (RFSSW) is a special form of Friction Stir Spot Welding (FSSW), in this process, the end hole is closed with the material, which is displaced during penetration. The result is a clean, closed surface.

The RFSSW provides, inter alia, a good alternative to the attachment method, such as Clinching or riveting. In contrast to riveting, intermetallic corrosion can be ruled out in the case of joints of the same type.

This process also uses the proven Stirtec quality control tool to provide 100% traceability.

The FSSW technology

Friction Stir Spot Welding (FSSW) is a special variant of the classical “linear” FSW process. The FSSW-method is particularly attractive for joining tasks, at which sealing and adhesive media are applied to the surfaces between the components to be joined.

Benefits FSSW & RFSSW

  • high process stability
  • process tolerant with respect to deviations in shape in the joining zone
  • can also be used when using sealants or adhesives in the joint zone or for coated metal sheets
  • environmentally and workplace friendly joining process
  • low distortion due to low heat input
  • little influence on the back of the weld
  • easy to automate
  • RFSSW: flat surface

Friction Stir Processing

The FSP technology

The increasing demands on the quality and the properties of manufactured components demand new cost-effective solution methods in order to be able to meet these requirements on the material.

A new method is the microstructure preparation by using Friction Stir Processing, or FSP.

The FSP method can be used on the one hand to change the microstructure in layers close to the surface, but also to repair small pores, for example in die castings, to achieve a local improvement of the microstructure through FSP.

Benefits FSP

  • microstructural modification of cast alloys
  • fine-grained structure
  • variety of material shapes and sizes possible
  • good surface structure


Groundbreaking ceremony for the new FSW technology center
Kleine Zeitung (Primus, "Made in Austria") 28.05.2022, p.11
High-tech welding technology "Made in Styria"
Kleine Zeitung (Primus, Innovationsmotor Mobilität) 13.10.2021, p.15/16
Joining technology specialist Stirtec: In the big club
Friction Stir Welding of Steel for Pipeline Fabrication
Toguyeni, G.; Pfeiffer, C.; Caliskanoglu, O.; Oppeneiger, L.: Pipeline Technology Journal 4/2020. S. 28-37
A partner for welding the unweldable
Aluminium Times Jan/Feb 2017, p. 45.
Effect of RTE treatment on toughness of HSS weld metal
Cerjak, H-H.; Enzinger, N.; Caliskanoglu, O.; Figner, G.; Pudar, M.; Mendez Martin, F.; Domankova, M.: Proceedings 10th International Conference on Trends in Welding Research (2016). Tokyo, p. 213-216

Joining for Hydrogen

Applications for Solid State Joining

Due to the excellent gas-tightness, the wide application range is between Aluminum and High Strength Steel.

Market launch/feasibility using the patented Stirtec technology in the following industries started:

SSJ Hydrogen-1


Contact us for more information:

Solid State Joining (SSJ)

Stirtec technology fits perfectly in the future hydrogen economy by using Solid State Joining.

Unique features of Solid State Joining:

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FSW Applications for E-Mobility


Advantages of FSW

  • Suitable for serial production
  • Welding of die-cast aluminum
  • Gas-tight up to 20 bar
  • High reproducibility

for our FSW applications in the e-mobility sector

  • Electric motor housings
  • Large battery trays for BEV
  • Battery housings for PHEV
  • Electronic boxes (inverter, DCDC converter, booster, …)
  • Safety related structural parts
  • cable harnesses