| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to remarkably suppress the occurrence of wrinkles and make it possible to improve column strength when forming a constricted part in a subsequent step in a can body of a DI can subjected to DI processing by using a punch sleeve.SOLUTION: A punch sleeve 30 is provided for subjecting a cup-shaped body to DI processing to form a bottomed, cylindrical DI can. A can body 11 includes: a part 18 to be reduced in diameter which is positioned on a side closer to a can bottom than an opening end part 11a, and which is to be subjected to diameter-reducing processing in such a way that a diameter becomes smaller from the can bottom toward the side of the opening end part 11a; and a part 19 to be expanded in diameter which is positioned between the opening end part 11a and the part 18 to be reduced in diameter, and which is to be subjected to diameter-expanding processing in such a way that the diameter becomes larger from the can bottom toward the side of the opening end part 11a. In the outer peripheral surface of the punch sleeve 30, in a range corresponding to a region along a can axis O direction of the can body 11 at least from the opening end part 11a to the part 18 to be reduced in diameter, an outer diameter difference between a part corresponding to the opening end part 11a and a part corresponding to a portion other than the opening end part 11a is less than 10 μm.SELECTED DRAWING: Figure 6 |
