METHOD FOR MANUFACTURING EXPANDED CAN BARREL

PROBLEM TO BE SOLVED: To provide a method for manufacturing an expanded can barrel for obtaining the expanded can barrel having a smooth outer surface by use of a plurality of split type tools.SOLUTION: A first expanding shaping process of pressing the inner circumferential face of the can barrel 1 by press faces 4 of the respective split type tools 3 to expand the can barrel 1 to a prescribed outside diameter by inserting the plurality of split type tools 3 into the can barrel 1 in a convergence state and thereafter radially moving the respective split type tools 3 to the outside is performed. Next, a press position change process of making the press faces 4 of the split type tools 3 face to expansion marks 14 by separating the respective split type tools 3 from the inner circumferential face of the can barrel 1 and thereafter rotationally moving the can barrel 1 or the respective split type tools 3 in the circumferential direction of the can barrel 1 is performed. Subsequently, a second expanding shaping process of expanding the can barrel 1 to the prescribed outside diameter by pressing the expansion marks 14 in the inner circumferential face of the can barrel 1 by the press faces 4 of the respective split type tools 3 by radially moving the respective split type tools 3 to the outside in a position changed in the press position change process is performed.