There are 5 main FSW defects:
- Flash or burr on the edges of the weld ;
- Wormhole or tunnel which i.e. a porosity present on all or part of the length of the weld ;
- Lack of penetration which is an internal defect of the weld ;
- Hooking which i.e. a rise in surface of the material;
- Kissing-bond that appears when the adhesion is zero.
Flashes and wormholes are common defects in butt and through weld configurations. Find in our article detailed information on the main defects encountered in friction stir welding.