US3574280A
Expired / Lapsed
US
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Predictive gauge control method and apparatus with adaptive plasticity determination for metal rolling mills
Assignee: Westinghouse Electric Corp
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Filing: 1968-11-12
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Granted: 1971-04-13
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Expires: 1988-11-12
Abstract
Abstract A programmed computer control system provides on line predictive roll force gauge control and screwdown offset gauge control for a tandem hot steel strip mill. A gauge control program calculates corrective screwdown movement including that predictively required at each gauge controlled stand for optimum or near optimum gain correction of roll force error on the basis of on line detected roll force and screwdown position values at that stand and on the basis of a mill spring constant which is predetermined for that stand and a determined workpiece plasticity value for that stand. The workpiece plasticity values in determining the screwdown control action at each stand are adaptively modified during the workpiece rolling period on the basis of in process measurements of roll force and screwdown position at that stand. The control system operates the mill screwdowns in accordance with the program calculations made from the updated plasticity values.
Inventors
- 👤 Andrew W Smith Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:30
CPC Classifications
B; B21; B21B; B21B37/00; B21B37/16
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
192 words
A gauge control system for a rolling mill having at least one rolling stand with a screwdown controlled roll opening through which a workpiece is transported, said system comprising means for detecting roll force at the rolling stand, means for detecting the rolling stand screwdown position, means for determining roll force error on the basis of detected roll force and screwdown position values and predetermined roll force and screwdown position reference values, means for determining screwdown movement to provide for correct gauge, said screwdown movement determining means including means for predictively determining the amount of screwdown movement needed for correcting determined roll force error in accordance with a predetermined relationship with determined roll force error and predetermined values of workpiece plasticity and the stand spring constant, said screwdown movement determining means further including means responsive to said roll force detecting means and said screwdown position detecting means for making at least one on line determination of a value of the workpiece plasticity substantially as a function of the change in roll force produced by a screwdown position change at the stand, and means for controlling screwdown position to effect corrective screwdown movement.
Claim 2
Dependent Claim
192 words
A gauge control system for a rolling mill having at least one rolling stand with a screwdown controlled roll opening through which a workpiece is transported, said system comprising means for detecting roll force at the rolling stand, means for detecting the rolling stand screwdown position, means for determining roll force error on the basis of detected roll force and screwdown position values and predetermined roll force and screwdown position reference values, means for determining screwdown movement to provide for correct gauge, said screwdown movement determining means including means for predictively determining the amount of screwdown movement needed for correcting determined roll force error in accordance with a predetermined relationship with determined roll force error and predetermined values of workpiece plasticity and the stand spring constant, said screwdown movement determining means further including means responsive to said roll force detecting means and said screwdown position detecting means for making at least one on line determination of a value of the workpiece plasticity substantially as a function of the change in roll force produced by a screwdown position change at the stand, and means for controlling screwdown position to effect corrective screwdown movement.
Claim 3
Dependent Claim
65 words
A gauge control system as set forth in claim 1 wherein said workpiece plasticity determining means operates repeatedly to update the workpiece plasticity value as the screwdowns undergo movement during at least a portion of the workpiece rolling period, each of the operations of said workpiece plasticity determining means involving determination of the roll force change associated with the screwdown position change for that operation.
Claim 4
Dependent Claim
36 words
A gauge control system as set forth in claim 2 wherein each of the operations of said workpiece plasticity determining means requires a predetermined minimum amount of screwdown movement before execution of the operation is permitted.
Claim 5
Dependent Claim
20 words
A gauge control system as set forth in claim 3 wherein the minimum screwdown movement is at least 0.005 inches.
Claim 6
Dependent Claim
24 words
A gauge control system as set forth in claim 2 wherein said workpiece plasticity determining means is operative substantially throughout the workpiece rolling period.
Claim 7
Dependent Claim
129 words
A gauge control system as set forth in claim 2 wherein the rolling mill is a tandem mill having a plurality of roll force gauge controlled stands, at least one of each of said detecting means is provided for each of the roll force gauge controlled stands, said roll force error and screwdown movement determining means determine roll force error and predictively determine roll force corrective screwdown movement for each of the roll force gauge controlled stands, said plasticity determining means makes on line updating plasTicity determination for each of the roll force gauge controlled stands respectively on the basis of roll force changes associated with screwdown position changes at those stands and said screwdown controlling means makes corrective screwdown movement at the corresponding roll force gauge controlled stands.
Claim 8
Dependent Claim
82 words
A gauge control system as set forth in claim 2 wherein said roll force error and screwdown movement determining means include a digital computer system, said computer system having an input coupled to said detecting means and an output coupled to said screwdown controlling means, and means for operating said computer system to make the updating workpiece plasticity determinations from the determined roll force and screwdown position changes, said computer operating means further making the roll force error and screwdown movement determinations.
Claim 9
Dependent Claim
49 words
A gauge control system as set forth in claim 1 wherein the workpiece plasticity is determined in accordance with the equation where K equals the stand spring constant and DF equals the change in the stand roll force associated with DS which is the measured change in screwdown position.
Claim 10
Dependent Claim
96 words
A gauge control system as set forth in claim 8 wherein said determining means include a digital computer system having an input coupled to said detecting means and an output coupled to said screwdown controlling means, and means are provided for operating said computer system to determine the plasticity P and to determine roll force corrective screwdown movement from roll force error and the quantity where P equals the workpiece plasticity in units of force divided by units of distance and K equals the stand spring constant in units of force divided by units of distance.
Claim 11
Independent Claim
151 words
A method for providing gauge control in a rolling mill having at least one rolling stand with a screwdown controlled roll opening through which a workpiece is transported, the steps of said method comprising detecting roll force at the rolling stand, detecting the rolling stand screwdown position, determining roll force error on the basis of detected roll force and screwdown position values and predetermined roll force and screwdown position reference values, determining corrective screwdown movement to provide for correct gauge, said corrective screwdown movement step including predictively determining the amount of roll force corrective screwdown movement in accordance with determined roll force error and predetermined values of the workpiece plasticity and the stand spring constant, making at least one workpiece plasticity determination on line as a function of the change in roll force produced by a screwdown position change at the stand, and controlling screwdown position to effect corrective screwdown movement.
Claim 12
Independent Claim
151 words
A method for providing gauge control in a rolling mill having at least one rolling stand with a screwdown controlled roll opening through which a workpiece is transported, the steps of said method comprising detecting roll force at the rolling stand, detecting the rolling stand screwdown position, determining roll force error on the basis of detected roll force and screwdown position values and predetermined roll force and screwdown position reference values, determining corrective screwdown movement to provide for correct gauge, said corrective screwdown movement step including predictively determining the amount of roll force corrective screwdown movement in accordance with determined roll force error and predetermined values of the workpiece plasticity and the stand spring constant, making at least one workpiece plasticity determination on line as a function of the change in roll force produced by a screwdown position change at the stand, and controlling screwdown position to effect corrective screwdown movement.
Claim 13
Independent Claim
130 words
A method for operating a digital computer system employed for controlling the gauge of a workpiece transported through a screwdown controlled roll opening of at least one rolling stand, the steps of said method comprising determining roll force error on the basis of detected roll force and screwdown position values and predetermined roll force and screwdown position reference values, determining corrective screwdown movement to provide for correct gauge, said corrective screwdown movement step including predictively determining the amount of roll force corrective screwdown movement in accordance with determined roll force error and predetermined values of the workpiece plasticity and the stand spring constant, and making at least one workpiece plasticity determination on line as a function of change in roll force produced by a screwdown position change at the stand.
Claim 14
Independent Claim
130 words
A method for operating a digital computer system employed for controlling the gauge of a workpiece transported through a screwdown controlled roll opening of at least one rolling stand, the steps of said method comprising determining roll force error on the basis of detected roll force and screwdown position values and predetermined roll force and screwdown position reference values, determining corrective screwdown movement to provide for correct gauge, said corrective screwdown movement step including predictively determining the amount of roll force corrective screwdown movement in accordance with determined roll force error and predetermined values of the workpiece plasticity and the stand spring constant, and making at least one workpiece plasticity determination on line as a function of change in roll force produced by a screwdown position change at the stand.
Claim 15
Dependent Claim
96 words
A computer method as set forth in claim 11 wherein the workpiece plasticity is determined in accordance with the equation where K equals the stand spring constant and DF equals the change in the stand roll force associated with DS Which is the measured change in screwdown position, and wherein roll force corrective screwdown corrective movement is determined from roll force error and the quantity where P equals the workpiece plasticity in units of force divided by units of distance and K equals the stand spring constant in units of force divided by units of distance.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-12 | 1974-10-12 | 1975-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-12 | 1978-10-12 | 1979-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-12 | 1982-10-12 | 1983-04-13 | $7700.00 | Window Closed / Lapsed |