| 摘要 |
PURPOSE: To reduce a top mark by an easy operation and remarkably improve the yield of a band steel by making the tip of the band steel, which becomes the beginning of the coiling of a coil into a saw-tooth shape. CONSTITUTION: The tip of a band steel 1, which becomes the beginning of coiling on a mandrel 4, is made in a saw-tooth shape 12. When coiling the band steel 1, a second wind is first placed upon the only tip of the saw-tooth shape 12. In this part, a sheet bend caused by a difference in level occurs but it is very small, and in the other parts, since placing one upon another does not occur, coiling is performed without causing the sheet bend. Therefore, a top mark is remarkably reduced. After coiling the band steel once, the occurrence states of the top mark and other sheet bends have been investigated by uncoiling a coil. As a result of the investigation, a flaw is observed in the position ofπD of a first wind but the outside of it is not much influenced when the diameter of the mandrel 4 including a rubber sleeve 5 is expressed as D.
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