Airbus to Implement Friction Stir Welding?
If you're into the technology side, check out The TWI World Centre for Materials Joining Technology site. Tons of links there.
Quick summation here:
In friction stir welding, a cylindrical, shouldered tool with a profiled probe is rotated and slowly plunged into the joint line between two butted-together pieces of sheet or plate material. The parts have to be clamped onto a backing bar in a manner that prevents the abutting joint faces from being forced apart. Frictional heat is generated between the wear resistant welding tool and the material of the workpieces. This heat causes the latter to soften without reaching the melting point and allows traversing of the tool along the weld line. The plasticised material is transferred from the leading edge of the tool to the trailing edge of the tool probe and is forged by the intimate contact of the tool shoulder and the pin profile. It leaves a solid phase bond between the two pieces. The process can be regarded as a solid phase keyhole welding technique since a hole to accommodate the probe is generated, then filled during the welding sequence.