冷間圧延におけるオフゲージ低減の理論と実際

抄録

The causes of off gauge at the top and tail end of strip cold rolled on a tandem mill have been clarified theoretically and experimentally. Some counter-measures for reducing the length of off gauge have been adopted at the No. 3 cold tandem mill in Kimitsu Works of Nippon Steel Corp.,
(1) The off gauge at the top of strip is caused by reducing the rolling speed when the top edge of the strip is threaded through each stand by the off set of the rolling speed and by the decreasing in front slip. As the counter measures taken for these phenomena, current delay compensation and minor speed control by digital computer are efficient in reducing off gauge at the top of strip.
(2) The off gauge at the bottom of strip is caused by the rapid increasing of strip thickness at the i stand which is caused by the loss in back tension immediately after the tail end of strip leaves the i-1 stand. The counter-measure developed, reducing the back tension by narrowing the roll gap of the i stand before the tail end of the strip leaves the i-1 stand, is efficient in reducing off gauge at the bottom of strip.
The off gauge length of strip has been reduced by almost 50% by the adoption of these counter-measures.