| 摘要 |
A method for producing an ultrathin-wall seamless metal tube by a cold rolling method that employs a cold pilger mill of mechatronics drive type including a mechanism to give a feed and a turn angle to a tube material not only immediately before the start of a forward stroke but also immediately before the start of a backward stroke of rolling, the cold rolling method utilizing a roll having a tapered groove whose diameter gradually increases or gradually decreases from an engaging entry side to a finishing exit side of a pair of rolls, and a tapered mandrel whose diameter similarly gradually increases from the engaging entry side to the finishing exit side to elongate the tube material by reducing a wall thickness while expanding a mid-wall diameter of the tube material. In the above described method, by giving amounts of a turn angle and/or a feed equivalent or nearly equivalent to those of forward stroke to the tube material immediately before the start of a backward stroke as well, it is made possible to achieve a further increase in the reduction-rate of rolling, a further reduction of wall thickness and improvement of dimensional accuracy of the product. |
