Abstract: A friction stir processing system can include a rotatable die assembly. The rotatable die assembly can include a die body and a plurality of die segments. The die body includes a die base and a die stem. The die stem extends axially from the die base, the die stem defines an extrusion cavity, and the die body is formed from a first material. The plurality of die stems are coupled to the die stem. The plurality of die segments are disposed around the extrusion cavity to collectively form a die surface opposite to the die base. The plurality of die segments are formed from a different material than the die body.

Abstract: A friction stir processing system can include a rotatable die assembly. The rotatable die assembly can include a die body and a plurality of die segments. The die body includes a die base and a die stem. The die stem extends axially from the die base, the die stem defines an extrusion cavity, and the die body is formed from a first material. The plurality of die stems are coupled to the die stem. The plurality of die segments are disposed around the extrusion cavity to collectively form a die surface opposite to the die base. The plurality of die segments are formed from a different material than the die body.

Abstract: A process that uses friction stir welding to connect a tube, for example a thin gauge tube having a wall thickness of about 2.54 mm (0.100 inch) or less, to another element, such as a tube sheet of a heat exchanger. The process employs a tubular anvil that is installed into the end of the tube and which, in one embodiment, can provide material during the friction stir welding process. After the weld is complete, the weld zone between the tubular anvil and the tube is machined away and the anvil tube removed.

Abstract: A friction-stir mandrel includes a textured end portion integral with a body portion. The textured end portion is configured to friction-stir process a starting material forced across the textured end portion and through a die in a plasticized state to form a pipe. A pipe can be formed by forcing a starting material across a textured end of the mandrel and through a die in a plasticized state, so that the textured end of the mandrel breaks up existing grains of the starting material. The pipe is formed from material that is forced through the die. The friction-stir mandrel can be used with porthole die friction-stir extrusion, seamless tube friction-stir extrusion, and tube friction-stir drawing processes to provide tubing in which the grains are broken up by the textured portion of the friction-stir mandrel. The textured portion can include features, such as threads, ridges, studs, protrusions, and the like.