Abstract: A continuous mill plant for rolling steel plates having one or a plurality of rolling mills. The ratio of maximum rolling speed to minimum rolling speed of the plant is at least 3.0 but no more than 10.0 at the continuous rated output of an electric motor for driving the rolling mill.

Abstract: A cold-rolled strip manufacturing apparatus, in which a continuous cold reduction mill and a continuous annealing furnace are directly linked together, has a tension-leveller-type scale breaker for elongating hot-rolled breakdown by 2 to 7 percent, a scale scrubbing brush unit and an immersion-type continuous pickling tank installed upstream of the continuous cold reduction mill.Descaling of the hot-rolled strip coil is carried out by breaking the mill scale formed on its surface by causing the running strip to elongate and then the broken scale is removed from the surface. The percent elongation given to the strip is feedforward controlled on the basis of the manufacturing conditions of the hot-rolled strip coil and/or the properties and quantity of the mill scale formed. In another descaling method, the percent elongation given to the strip is feedback controlled on the basis of the condition of scale breaking and removing that is detected during the period in which the mill scale is broken and removed.

Abstract: A roll-changing apparatus for use with a rolling machine including a roll-changing truck, a roll-exchanging truck, a roll-setting truck and a roll rack facility which are used to transport sets of rolls in conjunction with one or more racks having vertically spaced-apart sets of rails for supporting and transferring the rolls. The rolls can be transferred by sliding them between individual racks mounted on each of the roll-changing truck, the roll-exchanging truck and the roll rack facility or a single rack can be rolled from the roll rack facility to the roll-exchanging truck and then to the roll-changing truck for transferring the rolls to and from the rolling machine. The roll-setting truck includes a set of vertically movable rails for aligning with a respective set of rails of a rack mounted on the roll rack facility. The roll rack facility includes a plurality of racks, each of which holds a set of used or reconditioned rolls.