Solid‐State Welding Processes

Solid-state welding theory emphasizes that the driving force for two pieces of metal to spontaneously weld to each other exists if the barriers to welding can be eliminated. All solid-state welding processes are based on this concept, and use some combination of heat, pressure, and time to overcome the barriers. Approaches include Resistance, Friction, Diffusion, Explosion, and Ultrasonic Welding. There are a variety of ways to create frictional heating, but the friction welding processes which use the rotation of one part against another are Inertia and Continuous (or Direct) Drive Friction Welding. This chapter discusses some approaches to friction welding which include a method that allows rectangular shapes to be welded (Linear Friction Welding), and a method using an additional pin tool that can create friction welds using conventional joint designs such as butt joints.