Friction Stir WeldingFriction welding is a solid state welding process that may be used for welding a wide range of materials. It uses the heat generated when two metallic surfaces are rubbed together at very high speeds. This normally involves rotating one of the components while the other is held stationary. Pressure is applied to the hot components, forcing the two surfaces together and some hot metal is pushed out of the joint area. The process, once initiated, runs automatically, and needs no filler metal or shielding gas. The equipment for friction welding requires drive motors to rotate and push the moving component and tooling to hold the stationary component. It is large and expensive and the cost increases as the size of components capable of being handled increases. At least one of the components needs to be of a cylindrical, or near-cylindrical, shape. The process is suitable for welding most metals and alloys. It is particularly useful for dissimilar metal joints where adverse metallurgical reactions prohibit use of fusion welding, such as joining aluminium to copper. The main safety issues are rotating machinery and hot metal.
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