Effect of angular velocity of the pin on material flow during friction stir welding

Finite element method was used to model the material flow of alloy Al 6061-T6 in friction stir welding (FSW) process and the relationship between the material flow and the angular velocity of the pin. The results show that the material flow on the retreating side is faster than that on the advancing side. With the increase of the angular velocity, the material flow becomes faster. The material in front of the pin moves upward due to the extrusion of the pin and is forced to rotate around the pin and then, the material behind the pin is forced to move downward, which makes the friction stir process continuing. The equivalent plastic strain correlates well with the boundaries of the different microstructure zones. With the increase of the angular velocity, the equivalent plastic strain is increased.