| 摘要 |
PROBLEM TO BE SOLVED: To provide a forming roll of a special shaped tube with which a layout pattern in the concave parts and the number of the concave parts are freely changeable in addition to that the dimensions of the concave parts can be kept in a prescribed accuracy without changing the forming rolls, and a forming method of the special shaped tube the strain of which is reduced. SOLUTION: This roll is a forming roll 1 in which small holes 2 for fixing pins 3 are provided on the concave bottom surface 11 and the pins 3 for forming the concave parts 5 on a tubular body are mounted in these small holes 2 freely attachably and detachably. The special shaped tube is formed at a single working stage by assembling the forming rolls 1 to a single forming stand. Furthermore, many projections 8 and projecting line parts 6 are provided on the bottom surface 11 of the roll by arranging many small holes 2 in the circumferential direction of the bottom surface 11 of the roll like the sequence of points. COPYRIGHT: (C)2004,JPO&NCIPI
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