| 摘要 |
PURPOSE:To prevent thickness increasing phenomena and to roll a pipe without decreasing a line speed in the stage of drawing of a metallic pipe by heating the tail end of a preceding pipe and the top end of a succeeding pipe in the fore stage of a rolling mill, restraining and holding the pipes, and joining the pipes by butting and pressing the same. CONSTITUTION:The preceding end of a material 4 discharged from a heating furnace 3 is brought into contact with the rear end of a material 6 during rolling with a stretch reducer 5 and both ends are heated and joined by a joining device 7 in the stage of drawing a metallic pipe with the rolling mill. The tail end part of the preceding pipe and the top end part of the succeeding pipe are heated with a heating coil 9 or the like in this stage and at least one material 8 of both pipes is restrained in the circumferential direction of the pipe by using at least one of tools 10, 11 located on both sides of the coil 9. The tools 10, 11 are moved to butt both end parts of the preceding pipe and the succeeding pipe and both end parts are joined by compressive force. The drawing of the pipe is accomplished continously without fluctuating the rolling speed by the above- mentioned method. |
