Abstract: A tube can be repaired from its interior surface by inserting into the tube a cylindrical repair member The cylindrical repair member is a memory metal which has a first martensitic size that is less than the internal diameter of the tube, and a second austenitic size that is at least as large as or larger than the internal diameter of the tube. The cylindrical repair member is inserted into the tube in the martensitic state and heated, causing it to revert to the austenitic state thereby expanding and covering said hole, forming a tight bond with the internal surface of the tube.

Abstract: A memory metal plug adapted to seal tubes includes a central shaft and a plurality of discs extending radially from said shaft. The shaft extends beyond the first and last disc. The juncture of the discs and the shaft is radiused, and, further, the thickness of the discs decreases near the perimeter of each disc. This allows the discs to be swaged significantly without breaking, which, in turn, facilitates their use in plugging tubes.

Abstract: A plug assembly for a tube includes a tapered wedge and a sleeve. The sleeve fits over the wedge and is placed in a tube. Relative movement of the wedge and the sleeve causes the sleeve to expand and plug the tube. The exterior surface of the wedge and the interior surface of the sleeve include annular grooves. One or more compression rings in either the grooves in the sleeve or wedge permit motion of the sleeve relative to the wedge only toward the large diameter portion of the wedge. This prevents the sleeve from separating from the wedge after being installed in a tube.