A Three Dimensional Numerical Investigation of a Donor Material in Friction Stir Welding

Excessive tool wear generated during the plunge phase of Friction Stir Welding has slowed the pace of expanding the Friction Stir Welding process to hard materials such as steel. This research uses a finite element model of the Johnson-Cook material constitutive law to investigate the shear stresses, axial forces, and temperatures experienced by the tool and the workpiece during the plunge stage of Friction Stir Welding. The model in this research was developed using the commercially available finite element analysis software ABAQUS/Explicit and consists of both a deformable workpiece and a deformable tool. By implementing the concept of using a donor material during the initial plunge phase, we are able to minimize the forces on the tool and generate localized pre-heating, therefore reducing tool fracturing and subsequent production replacement costs. Initial donor material experiments were conducted in order to confirm the feasibility of applying this method to the FSW process. Both numerical simulation and experimental data supports the concept of using a donor material to reduce tool wear and the need to implement this concept to further experimental work for further verification and setting of industry standards.