Automatic control method and apparatus for a rolling mill

Claim 2

In the method of controlling the gauge of work strip material passing through a tandem rolling mill having a plurality of roll stands, with each of said roll stands being initially adjusted in speed and roll opening for maintaining a desired relatively constant mass flow passage of said material through the roll stands with a desired tension condition between at least one pair of said roll stands, said method including the steps of: sensing a tension deviation from said desired tension condition, changing the speed of a selected one of said pair of roll stands in response to said tension deviation to correct said tension and adjusting the roll opening of the latter of said pair of roll stands in relation to the direction of the passage of said work strip material in response to the change of speed in said selected one roll stand and concurrently changing the speed of said selected one roll stand in response to resulting change in tension, for restoring said desired mass flow condition.

Claim 3

The method of claim 1 including the steps of: providing initial settings for the speeds and the roll openings of at least said pair of stands for said desired mass flow condition when the rolling mill operation is thread speed operation and threading the work strip material through said roll stands with said tension deviation sensing and speed adjustment steps being conducted during said thread speed operation of the rolling mill.

Claim 4

The method of claim 2, wherein said speed and roll opening adjusting steps are effected concurrently and with the speed adjusting step being performed with a faster response than the roll opening adjusting step.

Claim 5

In the method of controlling the gauge of work strip material passing through a tandem rolling mill having a plurality of roll stands adjustable in speed and roll opening, with the speeds and roll openings of the roll stands being initially adjusted to provide a desired mass flow of the strip material through the roll stands and such initial adjustment being effected at thread speed before the rolling mill is accelerated to normal run speed, said method including the steps of: sensing the tension of said work strip material between at least one pair of adjacent stands to determine a tension error in relation to a desired tension; controlling the speed relationship between the work rolls of said pair of stands in response to said tension error; controlling the opening between the rolls of the subsequent one of said adjacent roll stands in the direction of flow of the workstrip material in response to said tension error; with said speed and roll opening steps being coordinated to establish said desired mass flow condition at said thread speed while mAintaining the tension between said adjacent stands substantially in accordance with said desired tension.

Claim 6

In the method of controlling the gauge of work strip material passing through a tandem rolling mill having a plurality of roll stands adjustable in speed and roll opening, with the speeds and roll openings of the roll stands being initially adjusted to provide a desired mass flow of the strip material through the roll stands and such initial adjustment being effected at thread speed before the rolling mill is accelerated to normal run speed, said method including the steps of: sensing the tension of said work strip material between at least one pair of adjacent stands to determine a tension error in relation to a desired tension; controlling the speed relationship between the work rolls of said pair of stands in response to said tension error; controlling the opening between the rolls of the subsequent one of said adjacent roll stands in the direction of flow of the workstrip material in response to said tension error; with said speed and roll opening steps being coordinated to establish said desired mass flow condition at said thread speed while mAintaining the tension between said adjacent stands substantially in accordance with said desired tension.

Claim 11

The method of claim 6 including repeating the above recited steps for any pair of adjacent stands successively; the roll opening of the first of all the roll stands being accurately adjusted initially.

Claim 12

The method of claim 7 with the above recited steps being conducted at thread speed and including the further step of accelerating the mill to normal run speed after all tension errors between roll stands have been successively eliminated.

Claim 13

In apparatus for controlling the passage of a strip of material through a plurality of tandem roll stands with each said roll stands being adjustable in roll speed and roll opening to maintain a relatively constant mass flow condition for the material passing through said plurality of roll stands with a desired tension condition between said stands, the combination of: means for sensing a tension error between a selected two adjacent roll stands; means for converting said tension error into a speed correction signal; faster response means for controlling the speed of one of said two adjacent roll stands in response to said speed error correction signal; and slower response means for controlling the roll opening of the subsequent one of said two adjacent roll stands in response to said speed error correction signal.

Claim 14

In apparatus for controlling the passage of a strip of material through a plurality of tandem roll stands with each said roll stands being adjustable in roll speed and roll opening to maintain a relatively constant mass flow condition for the material passing through said plurality of roll stands with a desired tension condition between said stands, the combination of: means for sensing a tension error between a selected two adjacent roll stands; means for converting said tension error into a speed correction signal; faster response means for controlling the speed of one of said two adjacent roll stands in response to said speed error correction signal; and slower response means for controlling the roll opening of the subsequent one of said two adjacent roll stands in response to said speed error correction signal.

Claim 15

The apparatus of claim 9 with said faster response means being operative with a speed reference signal.

Claim 16

The apparatus of claim 9 with said means for sensing a tension error including a ramp function.

Claim 17

The apparatus of claim 9 wherein each pair of said roll stands is provided with such said means for sensing a tension error relative to adjacent roll stands, means for converting said tension error, faster response means and slower response means, and including means responsive to the speed of at least one of said work stands exceeding a predetermined transition speed level for disabling at least one of said faster response means and said slower response means to prevent operation thereof, said transition speed level corresponding to acceleration of the rolling mill to normal run speed.

Claim 18

The apparatus of claim 9 including means for providing a signal corresponding to the area of the work strip of material for modifying the operation of said sLower response means.

Claim 19

The apparatus of claim 9 including means for providing a signal corresponding to the velocity of said work strip material for modifying the operation of said slower response means.