Abstract: A method and apparatus for ultrasonically welding the overlapped portions of a continuous metal strip that has been rolled about a longitudinal axis to form a tubular product. The metal strip is rolled around the outer surface of an internal mandrel by means of one or more forming tools disposed around the mandrel. At the exit end of the forming tool, a stationary, rigid, non-resonant anvil is formed by a portion of the outer surface of the mandrel so that the anvil is located inside the rolled metal strip and supported by that portion of the mandrel which extends outwardly between the longitudinal edges of the strip upstream of the point where the strip edges are brought together. As the rolled metal strip is advanced, the longitudinal edges thereof are overlapped and passed over the anvil.