US3677045A - Method of feed-forwardly controlling a tandem rolling mill - Google Patents

Method of feed-forwardly controlling a tandem rolling mill Download PDF

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Publication number
US3677045A
US3677045A US877927A US3677045DA US3677045A US 3677045 A US3677045 A US 3677045A US 877927 A US877927 A US 877927A US 3677045D A US3677045D A US 3677045DA US 3677045 A US3677045 A US 3677045A
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United States
Prior art keywords
thickness
roll stand
stand
roll
screw down
Prior art date
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Expired - Lifetime
Application number
US877927A
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English (en)
Inventor
Tohru Arimura
Masamoto Kamata
Morio Saito
Hiromu Suzuki
Masakazu Iguchi
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JFE Engineering Corp
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Nippon Kokan Ltd
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Publication of US3677045A publication Critical patent/US3677045A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/16—Control of thickness, width, diameter or other transverse dimensions
    • B21B37/165—Control of thickness, width, diameter or other transverse dimensions responsive mainly to the measured thickness of the product
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/16—Control of thickness, width, diameter or other transverse dimensions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B21B1/24—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a continuous or semi-continuous process

Definitions

  • the thickness of the input material is measured at the entry side of the first roll stand and this value is related to the predetermined desired final thickness of the output material of the mill.
  • the screw down mechanism of the first roll stand and the peripheral speed of the rolls of the first roll stand are then adjusted as a function of the measured and desired final thicknesses to produce an output strip having uniform thickness.
  • the screw down and peripheral roll speeds are adjusted to maintain the incoming volumetric feed rate of the input material substantially constant.
  • This invention relates to a method of controlling a tandem rolling mill, such as a cold tandem or a hot tandem rolling mill, by means of preliminarily measuring the thickness of the input material in order to eliminate deviations of the thickness of the material produced.
  • One prior art control apparatus utilizes a feed-back control system in which the strip thickness is measured after rolling and the rolling mill is then adjusted to produce material of the required thickness.
  • the strip thickness measuring device (or meter) is provided at the delivery side of a rolling stand.
  • the strip thickness is then automatically controlled by feed-back from the meter by adjusting the screw down and/or the roll peripheral speed of the previous rolling stand.
  • the adjustment is a function of the deviation between the strip thickness at the delivery side and the predetermined desired thickness. Accordingly, the speed of response in controlling the strip thickness is very slow due to a time lag from the roll to the thickness measuring device.
  • strip thickness is controlled only after a deviation is detected, the deviation of thickness which initiates the operation of the adjustment mechanism cannot be corrected, and a defective length of material not having the desired thickness will be produced.
  • Another object of this invention is to provide an automated rolling system having substantially no interstand interaction which would otherwise cause thickness deviations.
  • a method of controlling a tandem rolling mill to produce output material having a predetermined desired thickness comprises the steps of detecting the thickness of the input material at the entry side of the first roll stand of said mill, adjusting the screw down mechanism of the first roll stand as a function of the detected thickness of the input material and as a function of the predetermined thickness of the final output material; and simultaneously adjusting the forward slip rate by adjusting the peripheral speed of the rolls of the first roll stand during the rolling operation, such that the final output material from the rolling mill has the desired thickness.
  • FIG. I is a schematic drawing of a prior art control system for a tandem rolling mill
  • FIG. 2 is a schematic drawing of a feed-forward control system according to the present invention.
  • FIG. 3 is a graph illustrating strip thickness variations for the present invention in contrast with the prior FIG. 1 shows a typical prior art feed-back system for a tandem rolling mill.
  • An X-ray thickness meter 2 is located at the delivery side of the roll stand to measure the thickness of the strip produced thereby. When the measured thickness of the strip differs from the desired thickness, the thickness is adjusted to the desired thickness by means of moving the screwdown 3 in the roll-stand.
  • Another X-ray thickness meter 4 is located at the delivery side of the final roll stand 5 (No. 5 stand) where the thickness of strip going out of the final stand 5 is measured. When the measured thickness differs from the desired one, the roll peripheral speed of the roll-stand is altered and inter-stand tension between No.
  • An alternative prior art method of measuring strip thickness comprises detecting the rolling load (p) and indirectly correlating the rolling load to strip thickness from a predetermined relation represented by the equation h Sr+ P/K.
  • FIG. 2 shows a schematic block diagram of the present invention.
  • a thickness meter 7 is provided at the entry side of the No. I roll stand which comprises rolls 8 and a screw down mechanism 9 coupled to the rolls 8.
  • a thickness meter 10 is provided at the delivery side of the No. 1 roll stand.
  • the screw down mechanism 9 is controlled by a screw down motor ll, and the mill rolls 8 are driven by the driving motor 12 which is controlled by speed control device 17.
  • Signals corresponding to the desired thickness of the strip or sheet is fed by an input device 13 to a thickness control device 14, the output of which is fed to two delay circuits 15.
  • the output of one delay circuit 15 controls motor speed control 17 and the output of the other delay circuit 15 controls the screw down mechanism 9 by means of screw down control circuit 16 and motor 11.
  • input device 18 feeds in signals corresponding to the desired value of the thickness of the sheet at the delivery side of the No. 1 roll stand to a control device 19, which compares the desired value with the measured value from meter 10 to further cause the thickness to be controlled by feed-back.
  • the thickness of the input material is measured by thickness meter 7.
  • This value is fed to control device 14 which relates it with the final desired value to provide an output signal for controlling roll stand No. l to provide the proper output strip.
  • the output of control device 14 is fed, via a delay 15, to control the screw down mechanism 9.
  • inter-stand tension between the No. 1 stand and the No. 2 stand (not shown) will vary. This variation is transmitted to the final roll stand and will affect the thickness of output products. Therefore, this inter-stand tension is simultaneously compensated for by altering the roll peripheral speed in No. I stand.
  • Another output of control device 14 is fed to the motor speed control circuit 17 to vary the roll peripheral speed.
  • the thickness measuring device 10, circuits I8 and 19 and averaging circuit A provided at the delivery side of the No. 1 roll stand, detect deviations of the outgoing strip thickness as a constant deviation signal.
  • the output of circuit 19 is fed back to adjust the screw down mechanism 9 in No. 1 stand so that the constant deviation may be compensated.
  • Control circuits 14 and 19 may be special purpose electronic computing circuits or may comprise part of a larger computer. These circuits, and particularly circuit 14, combine values in accordance with a predetermined equation (or equations) to produce an output. Various factors, such as the nature of the material being operated on are taken into account. The particular design of these circuits is dictated by specific system requirements and will vary from system to system. Implementation of such circuits should be apparent to those skilled in the art within the spirit of this invention.
  • this invention is characterized by stabilizing the thickness of the outgoing strip and its speed in the No. 1 roll stand by means of a. feed-forward control system.
  • the invention resides in keeping the incoming volumetric speed of strips at a constant value.
  • incoming volumetric speed is required to be constant in order to keep the strip thickness of the following roll stands at a constant desired value.
  • U is the incoming volumetric speed
  • h is the outgoing strip thickness of the No. 1 roll stand
  • v is the outgoing strip speed of the No. 1 roll stand
  • hr is the outgoing strip thickness of the final roll stand
  • the numeral l used in the above equations represents the No. 1 stand.
  • the coefiicients (2P/2H) l, (ZflZH) l and forward slip rate fl must be changed by the actual value obtained from the pass schedule during the rolling operation and in this case, of course, the time lag determined by the position of the thickness meter must be taken into consideration.
  • the graph of FIG. 3 shows the manner in which the strip thickness varies at the delivery side of the No. 1 stand in the present invention, compared with variations present in the conventional feed-back systems of the prior art.
  • the dotted line shows the prior art thickness variations and the solid line shows the thickness variations in the present invention.
  • This invention is not, of course, limited to the above described embodiment and can also be utilized in a hot tandem mill.
  • the system of this invention must be provided at the entry side of the No. 1 stand to measure both the thickness and the temperature of strip. This information will be fed to a device such as control device 14 which will generate output signals to control operation of the No. 1 stand.
  • Apparatus for use in a tandem rolling mill during continuous operation thereof to produce output material having a predetermined desired thickness using a feed-forward technique comprising:
  • a thickness measuring device located at the entry side of a first roll stand of said mill for measuring the thickness of the input material
  • Apparatus according to claim 1 further comprising:
  • a second thickness measuring device located at the output side of said first roll stand for measuring the thickness of the output material from said first roll stand
  • a feed-forward method for continuously controlling a tandem rolling mill during continuous operation thereof to produce output material having a predetermined desired thickness comprising the steps of:
  • a method according to claim 3 further comprising the steps of:
  • a method according to claim 3 comprising delaying adjusting of the screw down mechanism of said first roll for a predetermined period of time substantially corresponding to the amount of time required for the strip to pass from the point of thickness detection to the first roll stand.
  • a method according to claim 3 comprising delaying adjusting the peripheral speed of the rolls of the first stand for a predetermined period of time substantially corresponding to the amount of time required for the strip to pass from the point of thickness detection to the first roll stand.
  • said adjusting means includes first delay means for delaying adjustment of said screw down mechanism of said first roll by a time corresponding to the amount of time required for the strip to pass from the point of thickness detection to the first roll stand.
  • said adjusting means includes a second delay for delaying adjusting of said peripheral speed of said rolls of said first stand by a predetermined time which substantially corresponds to the amount of time required for the strip to pass from the point of thickness detection to the first roll stand.
US877927A 1968-11-19 1969-11-19 Method of feed-forwardly controlling a tandem rolling mill Expired - Lifetime US3677045A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8419868 1968-11-19

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US3677045A true US3677045A (en) 1972-07-18

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US (1) US3677045A (xx)
DE (1) DE1958162A1 (xx)
FR (1) FR2022985A1 (xx)
GB (1) GB1292310A (xx)
NL (1) NL6917282A (xx)
SU (1) SU405189A3 (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3863478A (en) * 1972-09-06 1975-02-04 Nippon Steel Corp System for controlling rolling mills
US4030326A (en) * 1975-08-25 1977-06-21 Hitachi, Ltd. Gage control apparatus and method for tandem rolling mills
CN102950155A (zh) * 2012-10-16 2013-03-06 河北钢铁股份有限公司唐山分公司 一种基于秒流量计算厚度的agc控制方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2808888C2 (de) * 1978-03-02 1983-03-10 SMS Schloemann-Siemag AG, 4000 Düsseldorf Walzanlage
DE19636560A1 (de) * 1996-09-09 1998-03-12 Siemens Ag Justierfrei einstellbare Kontaktkraft an Hilfsschaltern

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2325190A (en) * 1939-06-05 1943-07-27 Wheeling Steel Corp Metal rolling
US2883895A (en) * 1954-10-15 1959-04-28 Carl A Vossberg Rolling mill thickness control system
US3049036A (en) * 1957-04-08 1962-08-14 Westinghouse Electric Corp Automatic strip thickness control apparatus
US3101016A (en) * 1959-02-26 1963-08-20 British Iron Steel Research Rolling mills
US3169421A (en) * 1960-10-24 1965-02-16 Allis Chalmers Mfg Co Automatic gauge control
US3170344A (en) * 1961-09-19 1965-02-23 Gen Electric Method and apparatus for controlling the thickness of rolled strip material
US3186201A (en) * 1961-06-21 1965-06-01 Steelworks Automation Ltd Production of metal strip
US3212310A (en) * 1962-05-31 1965-10-19 Armco Steel Corp Automatic gauge and tension control system
US3332263A (en) * 1963-12-10 1967-07-25 Gen Electric Computer control system for metals rolling mill
US3507134A (en) * 1968-02-20 1970-04-21 Westinghouse Electric Corp Interstand tension control for tandem cold rolling mills
US3531961A (en) * 1968-03-13 1970-10-06 Westinghouse Electric Corp Method and system for controlling strip thickness in a tandem reduction mill

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2325190A (en) * 1939-06-05 1943-07-27 Wheeling Steel Corp Metal rolling
US2883895A (en) * 1954-10-15 1959-04-28 Carl A Vossberg Rolling mill thickness control system
US3049036A (en) * 1957-04-08 1962-08-14 Westinghouse Electric Corp Automatic strip thickness control apparatus
US3101016A (en) * 1959-02-26 1963-08-20 British Iron Steel Research Rolling mills
US3169421A (en) * 1960-10-24 1965-02-16 Allis Chalmers Mfg Co Automatic gauge control
US3186201A (en) * 1961-06-21 1965-06-01 Steelworks Automation Ltd Production of metal strip
US3170344A (en) * 1961-09-19 1965-02-23 Gen Electric Method and apparatus for controlling the thickness of rolled strip material
US3212310A (en) * 1962-05-31 1965-10-19 Armco Steel Corp Automatic gauge and tension control system
US3332263A (en) * 1963-12-10 1967-07-25 Gen Electric Computer control system for metals rolling mill
US3507134A (en) * 1968-02-20 1970-04-21 Westinghouse Electric Corp Interstand tension control for tandem cold rolling mills
US3531961A (en) * 1968-03-13 1970-10-06 Westinghouse Electric Corp Method and system for controlling strip thickness in a tandem reduction mill

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3863478A (en) * 1972-09-06 1975-02-04 Nippon Steel Corp System for controlling rolling mills
US4030326A (en) * 1975-08-25 1977-06-21 Hitachi, Ltd. Gage control apparatus and method for tandem rolling mills
CN102950155A (zh) * 2012-10-16 2013-03-06 河北钢铁股份有限公司唐山分公司 一种基于秒流量计算厚度的agc控制方法

Also Published As

Publication number Publication date
GB1292310A (en) 1972-10-11
NL6917282A (xx) 1970-05-21
SU405189A3 (xx) 1973-10-22
DE1958162A1 (de) 1971-01-14
FR2022985A1 (xx) 1970-08-07

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