APPARATUS FOR ADJUSTING SCREW-DOWN POSITION OF MILL ROLL WHICH CONSTITUTES THREE-ROLL TYPE MANDREL MILL, AND METHOD FOR MANUFACTURING SEAMLESS PIPE

摘要

[Problem to be Solved] There is provided a device for adjusting the rolling positions of rolling rolls, which is capable of, for example, restraining poor roll-biting of the front edge part of a pipe material rolled by a three-roll mandrel mill. [Solution] The device 100 for adjusting the rolling positions of rolling rolls R1 to R6 constituting the three-roll mandrel mill includes pressing-down devices 1 (P1 to P6) for moving the rolling rolls R1 to R6 in the rolling direction and a control unit 2 for controlling the pressing-down devices 1. Immediately after the front edge part of a pipe material T has begun to be rolled by the rolling rolls disposed on at least one rolling stand of the rolling rolls R1 to R6, the control unit 2 controls the pressing-down device 1 to move the rolling rolls in the closing direction. Preferably, the control unit 2 moves the rolling rolls disposed on at least one rolling stand of the rolling rolls R1 to R6 in the closing direction at a speed of 16 mm/sec or higher by using the pressing-down device 1.