To obtain a metal tube wherein the shape of a cross section whose inside is partitioned with a partition wall is uniform in the longitudinal direction and the partition wall is welded to a tube part via a sound weld zone.
A metal plate 20 for a partition wall is held between a pair of metal plates 10 for a tube body wherein a half-circle part 11 equivalent to a tube body divided in half is formed, and a fin part 13 is cut after welding three plates penetratingly. Any of a straight linear shape, shape curved in the intermediate part, curved shape may be used as the half-circle part 11 which is formed into the metal plate 10 for the tube body. When the half-circle part 11 is formed in the bent metal plate 10 for the tube body, a metal tube having a three-dimensionally bent partition wall is manufactured. Single or plural half-circle parts 11 are formed in the metal plate 10 for the tube body. When the metal plate for the tube body wherein plural half-circle parts are formed is used, the metal tube is simultaneously manufactured at the time of cutting the fin part after being integrally welded with the metal plate for the partition wall. The metal tube whose inside is partitioned with the partition wall is also manufactured through a continuous line wherein a metal band plate is used.
NAKAHARA NORIYUKI
INOUE SHOJI
