PURPOSE: To prevent the generation of a material short in length and to enhance the yield of material by reducing the allowance in pipe length and weight, by deciding whether or not the measured weight of a mother pipe or a stock is larger than an instruction weight, in performing a titled control basing on the weight of stock and the measured value of the length of pipe before and after rolling.
CONSTITUTION: In a case that the measured weight WBM of a mother pipe or a stock is larger than the instruction weight of said pipe or stock, and the instruction length LT of a rolled pipe is obtained even when the wall-thickness of pipe is made to be an ordinary target value; draw rolling is performed by setting the target length LTA of a rolled pipe, basing on an equation I , so that the wall thickness of rolled pipe is constant. Further, in a case that the weight WBM is less than the weight WB, the lower limit of the wall thickness of rolled pipe is larger than a securable set value, and the length LT can be secured by reducing the wall thickness of rolled pipe; the draw rolling is performed basing on, for instance, an equation II. Furthermore, in a case that the weight WBM is less than said set value and the length LT can not be secured even when the wall thickness of rolled pipe is reduced; the draw rolling is performed by setting the length LTA basing on the equation I so that the wall thickness of rolled pipe is constant.
| JPS62187508 | STRETCH REDUCING MILL |
| JP2682387 | [Title of Invention] Cold Rolling Method for Steel Pipe |
| WO/2003/068448 | PIPE WELDING DEVICE |
FUNIYUU YUTAKA
OKUMURA KIYOSHI
| JPS5340671A | 1978-04-13 | |||
| JPS5561308A | 1980-05-09 |