| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for efficient production of a different-and small-diameter copper tube having diameters and plate thicknesses different in an axial direction, and to provide the different-and small-diameter copper tube.SOLUTION: There is provided the method for production of a different-and small-diameter copper tube 1C which comprises a large-diameter portion 2, a small-diameter portion 3C having smaller diameter than the large-diameter portion 2 and a tapered portion 4C connecting the large-diameter portions 2 and the small-diameter 3C together. The method includes forming the small-diameter portion 3C in a copper tube 1A to be worked, by drawing using a plurality of dies 13, 23 having holes with inner diameters smaller than the outer diameter of an original tube. The plurality of dies 13, 23 are the split dies 13, 23 capable of being split into the split die pieces. |
