| 摘要 |
PURPOSE:To surely prevent generation of shape defects when a line speed is decelerated by changing over tension and elongation constant control to tension and rolling force constant control when the line speed is decelerated and returning said control to the tension and elongation constant control when the speed is reset. CONSTITUTION:The constant tension and constant elongation control is changed over to the constant tension and constant rolling force control simultaneously when or just before the rolling force at the deceleration of the line speed attains the predetermined lowest pressure at which edge seams are generated. The control is thereafter changed over to the constant tension and constant elongation control when the speed is reset. The lower limit of the rolling force is so set as to prevent said force from dropping down to the lowest rolling force at which the shape defects of a material having a certain width and thickness are generated or below in the above-mentioned manner. The elongation is changed when the line speed lowers. The drop of the rolling force is thereby compensated and the generation of the shape defects such as edge seams and middle waviness is surely prevented.
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