A method of friction welding comprises providing a first workpiece having a first weld surface and a second workpiece having a second weld surface. The first workpiece is arranged such that it tapers away from the first weld surface, the first workpiece converges in a direction away from the first weld surface. The first and second workpieces are arranged such that the first weld surface abuts the second weld surface. The first and second workpieces are oscillated relative to each other such that at least one of the weld surfaces of at least one of the workpieces moves relative to the other weld surface of the other workpiece such that the temperature increases at the weld surfaces to create a weld interface. The oscillation is stopped and the first and second weld surfaces are allowed to cool to weld the first and second workpieces together. The tapering of the first workpiece reduces the flow rate of weld flash material during the oscillation of the first and second workpieces relative to each other to reduce the formation of strain-induced porosity at the edges of the weld.