method of producing a heat exchanger, and a heat exchanger in accordance with the procedure law

摘要

PURPOSE:To prevent exactly leakage of a liquid of a flat tube, by recessing positively a weld part by a very small quantity, and absorbing exactly a brazing material, when a strip material is bend-formed to form a cylinder by welding the end parts, and also to form a flat shape. CONSTITUTION:A brass strip material 21 is bend and formed like a circle by use of a roll, and its end face is heated and welded with pressure, to form a cylinder 60 by welding. In this regard, the projection amount of welding beads 24, 25 of its weld 23 is made equal to plate amount of welding beads 24, 25 of its weld 23 is made equal to plate thickness of the strip material 21 through about 1/3. When this cylinder 60 is made round by a roll, the weld is recessed by the projection amount of the bead 25. Subsequently, when the cylinder 60 is formed to a flat tube 6 by a flattening-forming roll, the weld part 23 is further recessed and a groove 26 is formed. In this state, when said cylinder is made to pass through a solder-plating tank, solder 34 stays exactly in the groove 26, and a welding failure part can be restored. Subsequently, a corrugated fin is soldered to the flat tube 6.