Friction Stir Welding
Friction stir welding is a solid-state joining process where a rotating tool plasticizes and stirs the material along the joint edge without melting. It is excellent for hard-to-weld aluminum alloys.
Physical-Chemical Mechanism of Action
Friction stir welding uses the plasticity of the metal to shape and stir it along the joint edge. A rotating tool plasticizes the material under pressure without melting it. This results in a fine mixture of materials at the joint edge.
Metallurgical Relevance & Risks in Welding
Friction stir welding is especially suitable for hard-to-weld alloys like aluminum, as it does not require melting processes. It reduces the risk of porosity and increases the mechanical properties of the joint zone. However, incorrect application can lead to uneven plasticizing or too high pressure, causing cracks or deformation in the workpiece.
Workshop Practice & Instructions
For successful friction stir welding, it is crucial to set the correct tool and pressure. A typical pressure is between 100 and 200 N/mm². The tool rotation speed should be between 500 and 1000 rpm. It is important to prepare the joint edge cleanly and continuously monitor the process to ensure no deformation or cracks occur.