Method for processing material to be rolled on a rolling line, and rolling line

Abstract

A method for machining rolled stock (6) in a rolling train (2), the train including at least one rolling block (20, 20a, 20b) having at least two rolling stands (4) with each stand including at least one roll (13). Each rolling stand (4) has a separate drive (8) with a speed controller (14) for its roll (13). A time (t.sub.zw) that is dependent on the point in time (tB) that an actual loading moment is applied to the drive (8) of the first rolling stand (4) of the rolling block (20, 20a, 20b), for controlling the speed of the drive (8). An additional value (ZW), dependent on an expected actual loading moment, is fed to the speed controller (14) of each drive (8). Also, a rolling train (2) for machining rolled stock (6), is disclosed having the features above and having an open-loop/closed-loop control unit (24), in which software for the method is implemented.

Claims

1. A method for rolling materials to be processed in an advancing direction on a rolling line wherein the rolling line includes at least one rolling section, each rolling section having at least two roll stands arranged in the advancing direction, each roll stand having at least one roll configured and operable for enabling movement of the materials in the advancing direction; a separate respective drive with a rotational speed regulator for the at least one roll of each roll stand for moving the materials in the advancing direction; the method comprising: determining a first point in time at which a real load moment is imposed on the drive of the first roll stand by material tracking of the material being rolled; and at a second point in time, which depends on the first time point at which the real load moment caused by the materials moving in the advancing direction is imposed on the drive of the first roll stand in the rolling section, feeding a supplementary value, which is a function of an expected real load moment, to the rotational speed regulator of each drive, wherein the feeding of the supplementary value is simultaneous with the rotational speed regulator of the drive of the first roll stand and with the rotational speed regulators of the drives of the subsequent roll stands in a same rolling section such that the supplementary value regulates the rotational speed regulators to regulate the rotation speeds of the drives.

2. The method as claimed in claim 1, wherein the rotational speed regulator incorporates a PI-regulator and the method further comprising feeding the supplementary value as preloading of an I-component of the PI-regulator.

3. The method as claimed in claim 2, further comprising determining the expected real load moment and the supplementary value by reference to a pass plan for processing the materials.

4. The method as claimed in claim 1, wherein: determining said second point in time for feeding said supplementary value to the rotational speed regulator of each said drive takes into account delays in the rotational speed regulator and in the drives.

5. A method for rolling materials to be processed in an advancing direction in a rolling line wherein the rolling line includes at least one rolling section, each rolling section having at least two rolling stands arranged in the advancing direction, each roll stand having at least one roll configured and operable for enabling movement of the materials in the advancing direction; a separate respective drive with a rotational speed regulator for the at least one roll of each roll stand for moving the materials in the advancing direction; the method comprising: determining a first point in time at which the real load moment is imposed on the drive of the first roll stand by reference to a measurement of a rolling force at the first roll stand; and at a second point in time, which depends on the first time point at which the real load moment caused by the materials moving in the advancing direction is imposed on the drive of the first roll stand in the rolling section, feeding a supplementary value, which is a function of an expected real load moment, to the rotational speed regulator of each drive, wherein the feeding of the supplementary value is simultaneous with the rotational speed regulator of the drive of the first roll stand and with the rotational speed regulators of the drives of the subsequent roll stands in a same rolling section such that the supplementary value regulates the rotational speed regulators to regulate the rotational speeds of the drives.

6. The method as claimed in claim 5, further comprising: determining the point in time at which the real load movement is imposed on the drive of the first roll stand by using a strain gauge for measuring the rolling force.

7. A rolling line for the processing of materials to be rolled, the rolling line comprising: at least one rolling section having at least two roll stands, and each roll stand having at least one roll; and a separate drive with a rotational speed regulator configured for driving and regulating the at least one roll of each roll stand; and a control/regulation unit configured and operable for controlling the speed regulators for the rolls such that at a first point in time at which a real load moment caused by the materials moving in an advancing direction is imposed on the drive of the first roll stand in the rolling section determined by material tracking of the material being rolled by one or more hot metal detectors, and at a second point in time which depends on the first time point, feeding a supplementary value, which is a function of an expected real load moment, to the rotational speed regulator of each drive, wherein the feeding of the supplementary value is simultaneous with the rotational speed regulator of the drive of the first roll stand and with the rotational speed regulators of the drives of the subsequent roll stands in a same rolling section such that the supplementary value regulates the rotational speed regulators to regulate the rotation speeds of the drives.

8. A rolling line for the processing of materials to be rolled, the rolling line comprising: at least one rolling section having at least two roll stands, and each roll stand having at least one roll; and a separate drive with a rotational speed regulator configured for driving and regulating the at least one roll of each roll stand; and a control/regulation unit configured and operable for controlling the speed regulators for the rolls such that at a first point in time at which a real load moment caused by the materials moving in an advancing direction is imposed on the drive of the first roll stand in the rolling section determined by material tracking of the material being rolled by a measurement device for measuring the rolling force on the first roll stand, at a second point in time which depends on the first time point, feeding a supplementary value, which is a function of an expected real load moment, to the rotational speed regulator of each drive, wherein the feeding of the supplementary value is simultaneous with the rotational speed regulator of the drive of the first roll stand and with the rotational speed regulators of the drives of the subsequent roll stands in a same rolling section such that the supplementary value regulates the rotational speed regulators to regulate the rotation speeds of the drives.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a further description of the invention, reference is made to the exemplary embodiments in the drawings. Shown in a schematic sketch of the principle are:

(2) FIG. 1 schematically represents a section of a rolling line with successive roll stands and with a separate drive for each roll stand,

(3) FIG. 2 is a schematic representation of a rotational speed regulation for the drives on the rolling line.

DESCRIPTION OF EMBODIMENTS

(4) FIG. 1 shows a section of a rolling line 2 with two rolling sections 20, e.g. an intermediate section 20a and a finishing section 20b. A rolling section 20 incorporates at least two roll stands 4 each with at least one roll 13, e.g. two rolls 13, for the processing of a material to be rolled 6. FIG. 1 shows, by way of example, eight successive roll stands 4, for the sake of clarity only illustrating those for the finishing block 20b, of a rolling section 20 through which passes the material to be rolled 6, e.g. a billet which is being rolled down to wire.

(5) Assigned to each roll stand 4 is a separate drive 8, incorporating a motor 10 and a gearbox 12, with a rotational speed regulator 14 which, for the sake of clarity, in FIG. 1 is only drawn in for one roll stand 4. The rotational speed regulator 14 regulates the rolls 13 of the drive 8 concerned to a setpoint value, n.sub.Soll, for the rotational speed. For this purpose, an actual value of the rotational speed, n.sub.Ist, is continuously sensed by the rotational speed regulator 14 of the drive 8, is compared with the setpoint value for the rotational speed, n.sub.Soll, which is determined e.g. by reference to a pass plan, and is adjusted to it. For the purpose of control and regulation by the rotational speed regulator 14, the rolling line 2 incorporates a control/regulation unit 24also shown for only one roll stand 4in which is implemented software for carrying out the method.

(6) FIG. 2 shows a rotational speed regulator 26, for a rolling section 20 with several roll stands 4, for regulating the rotational speeds n.sub.Ist,i of all the drives 8, and thus of the rolls 13 of the roll stands 4 in the rolling section 20, e.g. of the finishing section 20b. Assigned to each drive 8 is a rotational speed regulator 14, which incorporates a PI-regulator, which senses and regulates a difference to be regulated between the actual value of the rotational speed n.sub.Ist,i and the setpoint value for the rotational speed n.sub.Soll,i. In addition, the rotational speed regulator 26 incorporates for each drive 8 a current or torque regulation loop 28, as appropriate, which supplies the motor 10 with current and controls it to a desired operating point, and which in its regulation takes into consideration the moments of inertia of the drive.

(7) At a point in time t.sub.B, the first roll stand 4 of the rolling section 20 has imposed on it a real load moment. At a time point t.sub.zw, which depends on this time point t.sub.B, a supplementary value ZW, which depends on the expected real load moment, is fed to the rotational speed regulator 14 of each drive 8 for the purpose of regulating the rotational speeds of the drives 8. So all the drives 8 are preloaded with a supplementary value ZW at a point in time t.sub.zw, which has been determined as a function of the time point t.sub.B and which lies, for example shortly before, at, or shortly after the time point t.sub.B of the load imposition. This is fed to the relevant PI-regulator of the drive 8 concerned, as a preloading of the I-component. Thus at the time point t.sub.zw the relevant supplementary value ZW is fed to each drive 8, or to the relevant rotational speed regulator 14, as appropriate. By this means, a drop in the rotational speed, that is a reduction in the actual rotational speed n.sub.Ist,i, at all the roll stands 4 is decreased or largely avoided, so that the ratio of the rotational speeds of the individual roll stands 4, to each other and to the last roll stand in the rolling section 20a, remains constant.

(8) The expected real load moment and the supplementary value ZW concerned are here determined by reference to a pass plan and are fed to the PI-regulator of the relevant rotational speed regulator 14 at a time point t.sub.zw. After the preloading of the I-component with the supplementary value, in the next cycle of the system the rotational speed regulator 14 is released again and regulates the difference to be regulated, between the actual value of the rotational speed n.sub.Ist,i and the setpoint value of the rotational speed n.sub.Soll,i.

(9) In order to determine the time point t.sub.B at which the load is imposed, there is a measurement device 22, as shown in FIG. 1. Using this measurement device 22, the time point t.sub.B at which the load is imposed on the first roll stand 4 is determined from the actual load moment, for example by reference to a measurement of the rolling force M. The measurement device 22 for measuring the rolling force is constructed as a strain gauge, which is arranged in the first roll stand 4.

(10) In addition, the time point t.sub.B at which the real load moment is imposed on the first roll stand 4 is determined by means of material tracking. For this purpose, the measurement device 22 has a hot metal detector 23, which is arranged before the first roll stand 4 and which detects the point in time at which it is passed by the material being rolled 6. The point in time t.sub.B at which the real load moment will be imposed on the first roll stand 4 is thus determined even before the material being rolled 6 enters into the first roll stand 4 of the rolling section 20. The time point t.sub.zw is then determined as a function of the point in time t.sub.B at which the real load moment is imposed on the first roll stand 4. At the time point t.sub.zw, the material being rolled 6 is, as indicated in FIG. 1 by dashed lines, still before the first roll stand 4.

(11) In determining the time point t.sub.zw as a function of the time point t.sub.B, account is also taken of delays, for example, the moment of inertia of the motor torque M.sub.mot,I as it rises, which typically causes a delay of 10 to 50 ms. Correspondingly, the feeding of the supplementary value ZW takes place at a time point t.sub.zw which lies shortly before the point in time t.sub.B of the imposition of the load. Because a relevant supplementary value ZW is fed to all the rotational speed regulators 14, a drop in the rotational speed, when the material being rolled 6 enters the first roll stand 4 of a rolling section 20, is minimized at all the drives 8. This ensures the synchronicity of the individual roll stands 4 in the rolling section 20b and of the last stand of the rolling section 20a, that is, the ratio of their rolling speeds to one another, when the material being rolled 6 enters the rolling section 20b. Hence, a rotational speed ratio for the roll stands 4, prescribed in the pass plan, remains constant during the entire processing of the material being rolled 6. By this means, loop formation between the individual roll stands 4 of a rolling section 20, and between the rolling sections 20a and 20b, is prevented.

(12) Furthermore, during the processing of the material being rolled 6 the relevant supplementary value ZW is adjusted by reference to correction factors K.sub.i, by which means the supplementary values can still be trimmed for each drive, and can thereby be made a better match by eliminating incalculable effects from contamination.

(13) Although the invention has been illustrated and described in more detail by the preferred exemplary embodiment, the invention is not restricted by the examples disclosed, and other variations can be derived from it by a person skilled in the art without going outside the scope of protection of the invention.