The Studies of Material Two-Dimensional Plastic Flow in Friction Stir Welding

The sew horizontal material flow in friction-stir-butt-welded LF6 was investigated by using insert tracer material which was made of T1. The result indicated that the sew material flow was asymmetrical during friction stir welding. In advancing side, some material flowed forward and some flowed back. In retreating side, the material only flowed forward and some flowed into advancing side. To analyze the sew horizontal material flow pattern, a tentative two-dimension extrusion mode was presented based on the assumption that there was a thermal plastic zone closed to the pin and the shape of the zone was steady during welding. We studied the thermal plastic material flow around the pin using the theory of action separation and combination, and the result that the tracer material flow was simulated by the mode could explain what we investigaed in experiment.