Rotary Welding, commonly referred to as Rotary Friction Welding, is the most popular type of friction welding. It is primarily used for parts where at least one component has a rotationally symmetrical shape, such as tubes or bars. In this solid-state process, one part rotates at high-speed while being pressed against a stationary part. The frictional heat generated at the interface softens the material, allowing the parts to forge together when the rotation stops. Rotary Welding is highly effective for creating strong, consistent joints in automotive, aerospace, and manufacturing applications.
Linear Welding, or Linear Friction Welding, is used when the moving part does not need to be rotationally symmetrical. Instead of rotating, one part moves in a high-speed linear motion while pressing against a stationary part. This process is ideal for jet engine components, near-net shapes, and other applications where the limitation is based on the moving part’s mass rather than the interface geometry.
In comparison, Friction Stir Welding (FSW) is used for seam or butt welds in aluminum plates, extrusions, and sheets. A rotating pin tool moves along the seam between two stationary parts, creating a solid-state weld with high strength and low distortion. FSW is particularly effective for joining thin components without a length restriction, making it ideal for long, continuous welds.