Friction Stir Welding
Friction stir welding is a metal joining alternative to vacuum furnace brazing, laser welding, gun drilling, heat pipes, and conventional welding. Friction stir welding is accomplished by rotating a cylindrical tool along a seam to be joined. The tool is shouldered with a profiled pin that projects into the parts being joined. Heat is generated via rotational friction between the tool and parts. The heat causes the materials to soften without reaching melting point and allows the pin to traverse along the joint. As the tool moves, the material in front of the pin is plasticized by the frictional heat and displaced to the back of the pin. The material cools to form a solid state full penetration weld.
Applications:
- Joining raw plates to support large monolithic parts
- Liquid cooled cold plates for high heat electronics – design internal cooling paths and integral heat sinks and FSW for strength and high pressures
- Sealing cryogenic and aviation fuel tanks
- Military rockets and missiles
- Lens plates
Benefits:
- Can be welded and machined in the same set up
- Unlike conventional welding, all grades of aluminum can be FSW
- Low distortion, even in long welds and thin materials
- Depending on the application, can be 80% to 90% of the base metal characteristics
- No porosity
- Eliminates most joint prep and post weld processing
