THE EFFECT OF TOOL GEOMETRY ON MATERIAL FLOW BEHAVIOR OF FRICTION STIR WELDING OF TITANIUM ALLOY

Based on the RNG k-e model, the finite volume model of friction stir welding of Ti6Al4V alloy is established by ANSYS FLUENT software. The effect of rotational tool geometry on titanium alloy flow behaviour is exhibited. The results of numerical simulation show that the flow direction of material near the rotational tool is the same as that of the rotational direction of the rotational tools.. The flow velocity of material near the rotational tool is much bigger than that of other regions in a weldment while the peak value appears near the shoulder edge. Changing either the rotational tool shoulder diameter or the pin tip diameter, the flow direction of material during the welding process will always remain unchanged. With an increase of the shoulder and pin tip diameter, the material flow velocity increases. However, from the point of view of elimination of root defects, increasing the diameter of the pin tip is better than increasing the diameter of the shoulder.