Retraction friction stir welding is a new kind of friction stir welding technology developed to eliminate the keyhole after welding. The shoulder of the tool and the pin are separated. The up and down movement of pin can be adjusted by the driving machine, so that the pin is gradually withdrawn into the shoulder before the welding is completed, so as to fill and eliminate the keyhole of the weld (no keyhole). The retraction friction stir technique is especially suitable for welding products such as cylinder weld, which effectively guarantees the integrity of the product structure after welding.
Retraction FSW tool
（1）Common aluminum alloy(4XXX, 5XXX, 6XXX）
1.The keyhole can be filled or eliminated (no keyhole);
2. Widely used in FSW of cylinders and enclosure;
Wheels, cylinders, tanks, etc.
（2）High-strength aluminum alloy
（3）Cast aluminum alloy