Method and Apparatus for Producing Strip Having a Variable Thickness

1 . Method for producing strip having a variable thickness in its length direction, in particular a repetitive thickness variation, using a stand of a rolling mill, wherein the strip has a thickness D 1 when entering the mill stand and a thickness D 2 when leaving the mill stand, comprising

using the speed of the strip when leaving the mill stand as an input to control the speed of the rolls in the mill stand, and

keeping the strip between the mill stand and equipment downstream of the strip at a certain tension, the tension of the strip being used as an input for controlling at least one member of the group consisting of the speed of the mill stand and the speed of the downstream equipment.

2 . The method according to claim 1 , wherein a decoiler supplies the strip to the rolling mill and a coiler takes up the rolled strip,

wherein a first tension measuring device measures the tension in the strip entering the rolling mill and a second tension measuring device measures the tension in the strip leaving the rolling mill,

wherein a speed measuring device measures the speed of the strip leaving the rolling mill,

wherein the speed and tension measured with the speed measuring device and the second tension measuring device are used as input to control the rolling speed of the rolling mill.

3 . The method according to claim 2 , wherein the speed and tension measured with the speed measuring device, the first tension measuring device and the second tension measuring device are used as input to control the tension in the strip entering the rolling mill using a dancer between the decoiler and the rolling mill.

4 . The method according to claim 2 , wherein the speed and tension measured with the speed measuring device, the first tension measuring device and the second tension measuring device are used as input to control the decoiling speed of the decoiler.

5 . The method according to claim 1 , wherein the speed of the strip leaving the mill stand is kept approximately constant.

6 . The method according to claim 1 , wherein the strip leaving the mill stand is given a repetitive thickness variation having a repeating profile length of at most 4 meter.

7 . The method according to claim 1 , wherein a program is provided for determining the thickness D 2 in the strip, the program controlling the gap of the mill stand.

8 . The method according to claim 1 , wherein a program is provided for controlling the speed of the strip when entering the mill stand.

9 . The method according to claim 1 , wherein the rolling mill used is a single stand rolling mill.

10 . Apparatus for producing strip having a variable thickness in its length direction, the apparatus comprising:

a stand of a rolling mill,

upstream equipment,

downstream equipment,

a tension measuring device for measuring the tension in the strip leaving the mill stand and/or a speed measuring device for controlling the speed of the strip leaving the mill stand,

wherein a dancer or looper has been placed between the upstream equipment and the mill stand to accommodate changes in strip length, and

wherein no dancer or looper has been placed between the mill stand and the downstream equipment.

11 . The apparatus according to claim 10 , wherein a further tension measuring device has been provided for measuring the tension in the strip entering the mill stand.

12 . (canceled)

13 . The method according to claim 1 , wherein the strip's variable thickness in its length direction comprises a repetitive thickness variation.