| 摘要 |
<p>PURPOSE:To roll a seamless steel pipe so that its wall thickness is constant in the longitudinal direction, by controlling the caliber height of rolling rolls so that the rolling loads at least at the final two stands of a mandrel mill maintain the prescribed values. CONSTITUTION:While a shell 2 is being rolled by a mandrel mill consisting of plural stands, and at least at the final two stands of the plural stands; the shell 2 is passed, together with a mandrel bar 3 arranged in the inside of the shell 2, through a gap between rolling rolls 1a, 1b having calibers respectively; the rolling loads are detected by load cells, etc. to output the detected results to an arithmetic device 7. The device 7 calculates the height K of the caliber between a pair of the rolls 1a, 1b basing on the detected values so that a rolling load attains a prescribed value, to output a control signal to a caliber-height controller 5 basing on the calculated values, thereby controlling a caliber height controller 4.</p> |
