Abstract: The apparatus for joint sealing using tube expansion and friction welding includes a friction welding apparatus including a clamping assembly and a tube expansion apparatus. A tube having a beveled edge is inserted into an aperture in a tube sheet. The tube expansion apparatus expands the end of the tube with the beveled edge to swage the tube to the sheet. A tube sleeve having an edge beveled at an angle complementary to the beveled edge of the tube is clamped to the spindle of the friction welding apparatus. The tube sleeve is abutted to the beveled edge of the tube with the application of pressure and the spindle is rotated or oscillated to friction weld the tube sleeve to the tube and the tube sheet, forming a sealed joint. The process may be repeated to form a heat exchanger tube assembly having sealed joints.

Abstract: The tool for friction stir welding is a tool adapted to operatively engage a tube and a tubesheet to form a sealed joint. The tool has two components. The first component is a shoulder having orthogonal faces for simultaneously engaging the sheet and the tube, the shoulder defining a bore terminating in an aperture at the junction of the faces. The second component is a stir welding probe that is insertable into the bore and has an end exiting the aperture at the end of the bore. A forging pressure urges the shoulder against the junction of the tube and tubesheet. The probe is rotated about its axis, penetrating the tube and tubesheet and generating heat through friction to weld the tube to the tubesheet, while the shoulder is rotated about the tube so that the weld forms a seal about the circumference of the tube.