| 摘要 |
PURPOSE:To roll a seamless pipe so as to have the specified thickness in the longitudinal direction thereof by determining the outside diameter distribution of a mandrel bar from the temp. distribution thereof in the longitudinal direction measured right after the end of rolling the seamless steel pipe and controlling the caliber heights of rolling rolls of the stands with the measured values. CONSTITUTION:The outside diameter of a mandrel bar 3 measured in the longitudinal direction thereof right after the passage of the trailing end thereof through a final stand 1 (#n) upon ending of rolling of a seamless steel pipe (shell) 2 is inputted to a calculator 6. The calculator 6 calculates the spaces between the caliber surfaces of a pair of rolling rolls 1a, 1b and the surface of the 2nd and succeeding bars 3 in each stand in accordance with said measured value. More specifically, said calculator calculates the caliber height between the rolls 1a and 1b in the respective positions in the longitudinal direction of the 2nd and succeeding bars 3 for each of the stands so that the caliber height is kept constant in the longitudinal direction of the 2nd and succeeding bars 3. The calculator 6 controls a controller 6 in accordance with the calculated values, and the controller 6 adjusts an adjuster 4 in accordance with the signal from the calculator 6. |
