Abstract: A control is provided for a friction stir welding apparatus comprising a pin tool which includes a shoulder and a rotating pin extending outwardly from the shoulder of the pin tool and which, in use, is plunged into a workpiece formed contacting workpiece members to stir weld the members together. The control system controls the penetration of the pin tool into the workpiece members which are mounted on a support anvil. The control system includes a pin length controller for controlling pin length relative to the shoulder and for producing a corresponding pin length signal. A pin force sensor senses the force being exerted on the pin during welding and produces a corresponding actual pin force signal. A probe controller controls a probe extending outwardly from the pin, senses a parameter related to the distance between the probe and the supporting anvil and produces a corresponding probe signal.

Abstract: There is provided an apparatus for forming a weld joint between abutting ends of first and second tubular members. The welding apparatus includes a support ring defining an aperture therethrough. The support ring has first and second sides defining a channel therebetween. The first and second sides of the support ring define a plurality of supports spaced about the circumference of the support ring, each of which defines a gripping surface for contacting at least a portion of the exterior surface of a corresponding tubular member to thereby secure the abutting ends of the first and second tubular members at least partially within the aperture of the support ring. The welding apparatus includes at least one friction stir welding tool, which is movably and rotatably mounted within the channel defined by the support ring and projects toward the abutting ends of the first and second tubular members.

Abstract: An apparatus and method for friction stir welding a seam in a hollow container from the inside. The apparatus includes a weld head convertible between a retracted state to an expanded state. The retracted weld head fits through an opening in the container and then expands to enable formation of the weld. The weld head includes a frame and a least one friction stir welding spindle convertible between a retracted position adjacent the frame and an expanded position away from frame. The container may be a pressure vessel tank, with a circular weld being formed between a tubular mid-section and a hemispherical end cap. Desirably, multiple friction stir welding spindles that expand into a common plane are provided, and relative rotation between the weld head and container forms the circular seam. Force balance arms intermediate adjacent friction stir welding spindles expandable to contact the interior of the container may also be provided to help maintain the position of the weld head.

Abstract: A friction stir weld system for welding and weld repair has a base foundation unit connected to a hydraulically controlled elevation platform and a hydraulically adjustable pin tool. The base foundation unit may be fixably connected to a horizontal surface or may be connected to a mobile support in order to provide mobility to the friction stir welding system. The elevation platform may be utilized to raise and lower the adjustable pin tool about a particular axis. Additional components which may be necessary for the friction stir welding process include back plate tooling, fixturing and/or a roller mechanism.

Abstract: A friction stir welding tool is provided generally comprising three parts: a rotatable welding tool body (22) that has an outer threaded surface (32) and a probe (24) extending from a distal end of the body, a shoulder (26), which has a threaded inner surface (40) and a bore (36) at a distal end of the shoulder, and a jam nut (28), which has a threaded inner surface (42). The shoulder is threaded onto the tool body such that the probe extends from the shoulder through the bore by a preferred length. The jam nut is then threaded onto the tool body to secure the shoulder. The tool is operatively connected to a drive motor for rotating the tool body. The shoulder may include a knife edge projecting from the distal end (38) thereof adjacent the bore. The knife edge inhibits the weld material from migrating along the probe to intrude inside the shoulder, where it may prevent separation of the tool body and the shoulder when readjustment of the tool is necessary.

Abstract: An auto-adjusting pin tool for friction stir welding is presented wherein the pin tool automatically adjusts for welding materials of varying thicknesses, and the pin can be incrementally withdrawn from the workpieces thus eliminating any crater or keyhole in the weld. The inventive apparatus is comprised of a welding head housing a motor connected to a controller instrument package and an arbor supported by bearings. The arbor forms an interior cylinder and is encircled by a stationary slip ring though which are ported hydraulic passageways into the interior cylinder of the arbor such that a piston housed therein may be moved axially. Coupled to the piston is a pin tool which is treaded on its lower end and which is moveably seated in, and extending through, a shoulder housing having concave lower face. When welding, the rotating treaded end of the pin enters and stirs the workpieces while the lower face of the shoulder housing compacts the workpieces.