3-Dimensional CFD modelling of flow round a threaded friction stir welding tool profile

Abstract This paper describes the application of the computational fluid dynamics (CFD) code, FLUENT, to modelling the 3-dimensional metal flow in friction stir welding (FSW). A standard threaded tool profile is used for the analysis and features such as the tool rake angle, heat generation and heat flow are included. The primary goal is to gain a better understanding of the material flow around a complex FSW tool and to demonstrate the effect of the tool rake angle, and weld and rotation speed. The model captured many of the real process characteristics, but gave poor predictions of the welding forces. The model also generated an excessive amount of heat, which led to a large over-prediction in the weld temperature. These shortcomings can be overcome by using a viscosity relationship that includes material softening near the solidus or material slip at the tool interface.