US3768286A - Interstand tension regulator for a multistand rolling mill - Google Patents

Interstand tension regulator for a multistand rolling mill Download PDF

Info

Publication number
US3768286A
US3768286A US00230300A US3768286DA US3768286A US 3768286 A US3768286 A US 3768286A US 00230300 A US00230300 A US 00230300A US 3768286D A US3768286D A US 3768286DA US 3768286 A US3768286 A US 3768286A
Authority
US
United States
Prior art keywords
stands
speed
tension
error signal
strip material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00230300A
Other languages
English (en)
Inventor
R Peterson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AEG Westinghouse Industrial Automation Corp
Original Assignee
Westinghouse Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Application granted granted Critical
Publication of US3768286A publication Critical patent/US3768286A/en
Assigned to AEG WESTINGHOUSE INDUSTRIAL AUTOMATION CORPORATION reassignment AEG WESTINGHOUSE INDUSTRIAL AUTOMATION CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: WESTINGHOUSE ELECTRIC CORPORATION
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • B21B37/48—Tension control; Compression control
    • B21B37/52—Tension control; Compression control by drive motor control

Definitions

  • ABSTRACT An interstand tension regulator for tandem rolling
  • a method and apparatus are provided for controlling the gauge of strip material issuing from a tandem rolling mill by varying tension in the strip material between any two stands in the mill through control of one of the stands speed.
  • Tension between any two stands of the mill can be increased by decreasing the speed of the front stand or by increasing the speed of the rear stand. While the embodiment of the invention shown herein varies tension between the-last two stands with the tension regulator operating on the last stand speed, it should be understood that the tension regulator shown herein can be used on any stand to vary tension between it and either a preceding or succeeding stand.
  • the method of the invention contemplates generating an.electrical signal proportional to actual tension between the last two stands, generating an electrical signal proportional to desired tension between the last two stands, comparing the actual and desired signals to derive an error signal for varying the speed of the last stand, and modifying the error signal I as a function of the cross-sectional area of the strip between the last two stands and the speed of the next to the last stand to compensate for changes in the aforesaid transfer function.
  • FIG. 1 is an overall schematic diagram of the rolling mill gauge control system of the invention
  • FIG. 2 is a block diagram of the tension regulator shown in FIG. 1;
  • FIG. 3 is a schematic circuit diagram of the tension correction amplifier utilized in. the system of FIG. 2.
  • a five-stand tandem rolling mill is shown ineluding five stands S1, S2, S3, S4 and S5, only the rolls for stands S4 and S5 being shown in full lines since these are the only stands with which the tension regulating system shown herein is concerned, although the regulator of the invention can be used between any two stands.
  • Strip material 10 to be rolled passes between the rolls of the successive stands Sl-S5 and is progressively reduced in gauge while the speed of the strip material increases at the output of each stand.
  • the rolls for each of the stands are provided with drive motors, only motors M4 and M5 being shown in FIG. 1.
  • Motors M4 and M5 are controlled by speed regulators SR4 and SR5, respectively, which receive a master speed reference signal on lead 12 from a master mill speed controller, not shown.
  • the gauge of the strip material issuing from the last stand S5 is measured by an X-ray gauge 14 or the like which produces a signal on lead 16 proportional to actual gauge.
  • the signal from X-ray gauge 14 is compared at summing point 18 with a gauge reference sig nal on lead 20 determined by the operator of the mill, or possibly by a computer, this gauge reference signal being proportional to the desired output gauge. If the desired output gauge signal on lead 20 is not equal to the actual gauge signal on lead 16, an error signal is developed which is applied to an automatic gauge control circuit 22, the details of which may be had by reference to copending application Ser. No. 230,299, filed concurrently herewith and assigned to the Assignee of the present application.
  • a signal derived from a tachometer or pulse generator 23 is also applied to the automatic gauge control circuit 22. This signal is proportional to the circumferential speed of the last stand S5 and, hence, the speed of the strip material issuing from the mill.
  • the output signal from the automatic gauge control circuit 22 is then summed at summing point 24 with a tension references signal on lead 26 and with an actual tension signal on lead 28 derived from a tensiometer 30 in engagement with the strip material 10 between the last stands S4 and S5.
  • the signal from the gauge control circuit 22 and the tension reference signal 26 are summed and compared in subtractive relationship at point 24 with the actual tension signal from tensiometer 30.
  • the resulting signal is then applied as an error signal to the tension regulator 32 of the present invention.
  • the gauge of the strip material between stands S1 and S2 is measured by X-ray gauge 34 and applied to circuit 36 along with signals from tachometer generators or pulse generators 38 and 40.
  • Tachometer generator 38 is connected to the rolls of stand S1 and hence, produces an output signal proportional to the speed of stand 81; whereas tachometer generator 40 is connected to the rolls of stand S4 and produces an output signal proportional to the speed of stand S4.
  • X-ray gauge 34 of course, produces a signal proportional to the thickness of the strip material between the first and second stands.
  • G and G the gauges of the strip material entering and leaving the second stand S2; V and V the velocities of the strip material entering and leaving the second stand S2; and W the width of the strip material. Consequently, by knowing the gauge of the strip material between the first and second stands, the speed of the first stand, and the speed of the fourth stand, the area A of the strip material between the fourth and fifth stands S4 and S5 can be determined from the equation:
  • Circuit 36 therefore, performs this computation and derives a signal on lead 42 proportional to A the area of the strip material between stands S4 and S5.
  • This signal on lead 42 is applied to the tension regulator 32 of the present invention as shown in FIG. 1.
  • the tension regulator 32 controls the interstand tension between stands S4 and S5 by controlling stand S5 speed as shown in the block diagram of FIG. 1. However, it is important that the dynamics of stand S5 speed do not change throughout the operating speed range.
  • the tension error signal from summing point 24 is caused to pass through circuitry having a transfer function which is the inverse of that given by Equation (1) above, whereby the gain of the loop will not be altered for changes in strip cross-sectional area and mill speed.
  • FIG. 2 This circuitry is shown in block diagram form in FIG. 2 where the tension regulator 32 is enclosed by broken lines and includes a tension correction amplifier 46 and an area compensation circuit 48, comprising a divider.
  • the transfer function of the tension correction amplifier 46 is the inverse of that given by Equation (1) above, neglecting the crosssectional area A.
  • circuit 46 has a transfer function:
  • K is an adjustable gain which determines the crossover frequency or loop gain of the tension loop.
  • Equation (2) An examination of Equation (2) given above shows that the integral gain of the tension correction amplifier 46 must vary proportionally to stand speed V and inversely proportional to strip apparent modulus of elasticity E.
  • the apparent modulus of elasticity of steel E varies with steel composition and stand S5 reduction.
  • it will have to be incorporated into the amplifier 46 as a gain change via a potentiometer initiated by the mill operator or digital computer. This can be accomplished by a potentiometer in cascade with the integral part of the tension correction amplifier; however, the potentiometer is not shown herein since it is usually not required.
  • the proportional gain is a function of the distance L between stands S4 and S5 and the steel modulus of elasticity, which does not vary.
  • the details of the tension correction amplifier 46 are shown in FIG. 3. It will be noted that it includes two signal channels 50 and 52, both connected through potentiometers 54 and 56, respectively, to the tension error signal at summing point 24.
  • Channel 52 includes an integrating operational amplifier 58 having a feedback path including capacitor 60.
  • Channel 52 includes a proportional operational amplifier 62 having a resistor 64 in its feedback path.
  • the output of integrating operational amplifier 58 in channel 50 is applied to multiplier 66 along with the signal V proportional to stand S4 speed.
  • the output signal from multiplier 66 is applied through resistor 68 to summing point 70.
  • the output of operational amplifier 62 is applied through resistor 72 to the summing point while a movable tap on potentiometer 74, connected between the output of amplifier 58 and ground, is connected through resistor 76 to summing point 70.
  • the summing point 70 is then connected to the input of proportional operational amplifier 78 having a resistor 80 in its feedback path.
  • the channel 52 is necessary since it will be observed from Equation (2) given above that the integral gain of the tension controller integral amplifier 58 disappears at low speeds (e.g., threading speeds) since stand S4 speed V is very small at this time.
  • This low speed adjustment fixes the gain of the proportional amplifier 62 in channel 52, leaving the high speed gain to be adjusted by varying the gain a of the integral operational amplifier 58 via potentiometer 54 to obtain the desired tension response at mill speeds.
  • potentiometer 74 Because of the inaccuracy of the static multiplier 66 used at low voltage operation (i.e., low mill speeds), some permanent integral gain by potentiometer 74 is also used in the tension loop. This gives better tension loop response to mill disturbances during rolling operations. The permanent integral gain set by potentiometer 74, however, is very small.
  • the tension reference is programmed to have a constant strip tension in pounds per square inch
  • the tension reference signal is a representation of schedule cross-sectional are and the loop gain can be divided by tension reference to compensate for cross-sectional area variation.
  • the variation of strip tension in pounds with crosssectional area is known, the cross-sectional area can be calculated by an analog computer and used. Another method is to use an analog or digital computer to calculate cross-sectional area directly. To divide the tension loop gain by cross-sectional area requires an analog divider.
  • T interstand tension between said two stands
  • L is the distance between said two stands
  • A is the strip cross-sectional area between said two stands
  • V is the speed of the first of said two stands in the tandem rolling mill
  • V is the speed of the last of said two stands in the tandem rolling mill
  • E is the strip modulus of elasticity of the strip material
  • E is the apparent modulus of elasticity
  • S is the Laplace operator
  • T is the interstand tension between said two stands
  • L is the distance between said two stands
  • A is the strip cross-sectional area between said two stands
  • V is the speed of the first of said two stands in the tandem rolling mill
  • V is the speed of the last of said two stands in the tandem rolling mill
  • E is the apparent modulus of elasticity
  • S is the Laplace operation, the combination of where K, is a constant.
  • the apparatus of claim 7 including means for generating an electrical signal proportional to V means for generating an electrical signal proportional to'A, said circuitry incroporating means for multiplying said error signal by said signal proportional to V and means for dividing the product derived by multiplication by said signal proportional to A.
  • the apparatus of claim 9 including a second channel in shunt with said first channel, the second channel including a proportional operational amplifier, the outputs of said channels being summed and applied to said means for dividing by a signal proportional to A.
  • the apparatus of claim 10 including a signal channel in shunt with said multiplying means whereby a portion of the signal at the output of said integrating operational amplifier is applied directly to said summing point.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Metal Rolling (AREA)
US00230300A 1972-02-29 1972-02-29 Interstand tension regulator for a multistand rolling mill Expired - Lifetime US3768286A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US23030072A 1972-02-29 1972-02-29

Publications (1)

Publication Number Publication Date
US3768286A true US3768286A (en) 1973-10-30

Family

ID=22864671

Family Applications (1)

Application Number Title Priority Date Filing Date
US00230300A Expired - Lifetime US3768286A (en) 1972-02-29 1972-02-29 Interstand tension regulator for a multistand rolling mill

Country Status (5)

Country Link
US (1) US3768286A (enrdf_load_stackoverflow)
JP (1) JPS5021430B2 (enrdf_load_stackoverflow)
BE (1) BE796056A (enrdf_load_stackoverflow)
CA (1) CA968870A (enrdf_load_stackoverflow)
ZA (1) ZA73828B (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3848443A (en) * 1973-05-31 1974-11-19 Westinghouse Electric Corp Automatic control method and apparatus for a rolling mill
US3863478A (en) * 1972-09-06 1975-02-04 Nippon Steel Corp System for controlling rolling mills
US4087859A (en) * 1975-08-20 1978-05-02 Tokyo Shibaura Denki Kabushiki Kaisha Apparatus for measuring and controlling interstand tensions of continuous rolling mills
US4286447A (en) * 1979-03-12 1981-09-01 Westinghouse Electric Corp. Method and apparatus for automatic gauge control system for tandem rolling mills
US4333148A (en) * 1979-11-28 1982-06-01 Westinghouse Electric Corp. Process line progressive draw control system
US4998427A (en) * 1989-11-29 1991-03-12 Aeg Westinghouse Industrial Automation Corporation Method for rolling on-gauge head and tail ends of a workpiece
US5012660A (en) * 1989-11-29 1991-05-07 Aeg Westinghouse Industrial Automation Corporation Control system and method for compensating for speed effect in a tandem cold mill
US6845282B2 (en) 2002-09-04 2005-01-18 The Procter & Gamble Company Method of controlling tension in a web
US20060129266A1 (en) * 2004-12-10 2006-06-15 The Procter & Gamble Company Method of controlling tension in a web

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3045517A (en) * 1957-05-29 1962-07-24 Westinghouse Electric Corp Strip thickness control apparatus
US3049036A (en) * 1957-04-08 1962-08-14 Westinghouse Electric Corp Automatic strip thickness control apparatus
US3440846A (en) * 1967-06-06 1969-04-29 United States Steel Corp Apparatus for maintaining the gauge of steel strip
US3566639A (en) * 1968-11-21 1971-03-02 Gen Electric Gage control for multistand rolling mill
US3613419A (en) * 1969-08-01 1971-10-19 Westinghouse Electric Corp Rolling mill automatic gauge control with compensation for transport time

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3049036A (en) * 1957-04-08 1962-08-14 Westinghouse Electric Corp Automatic strip thickness control apparatus
US3045517A (en) * 1957-05-29 1962-07-24 Westinghouse Electric Corp Strip thickness control apparatus
US3440846A (en) * 1967-06-06 1969-04-29 United States Steel Corp Apparatus for maintaining the gauge of steel strip
US3566639A (en) * 1968-11-21 1971-03-02 Gen Electric Gage control for multistand rolling mill
US3613419A (en) * 1969-08-01 1971-10-19 Westinghouse Electric Corp Rolling mill automatic gauge control with compensation for transport time

Cited By (12)

* 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
US3848443A (en) * 1973-05-31 1974-11-19 Westinghouse Electric Corp Automatic control method and apparatus for a rolling mill
US4087859A (en) * 1975-08-20 1978-05-02 Tokyo Shibaura Denki Kabushiki Kaisha Apparatus for measuring and controlling interstand tensions of continuous rolling mills
US4286447A (en) * 1979-03-12 1981-09-01 Westinghouse Electric Corp. Method and apparatus for automatic gauge control system for tandem rolling mills
US4333148A (en) * 1979-11-28 1982-06-01 Westinghouse Electric Corp. Process line progressive draw control system
US4998427A (en) * 1989-11-29 1991-03-12 Aeg Westinghouse Industrial Automation Corporation Method for rolling on-gauge head and tail ends of a workpiece
US5012660A (en) * 1989-11-29 1991-05-07 Aeg Westinghouse Industrial Automation Corporation Control system and method for compensating for speed effect in a tandem cold mill
US6845282B2 (en) 2002-09-04 2005-01-18 The Procter & Gamble Company Method of controlling tension in a web
US20050055123A1 (en) * 2002-09-04 2005-03-10 The Procter & Gamble Company Method of adjusting a process output value
US7035706B2 (en) 2002-09-04 2006-04-25 The Procter & Gamble Company Method of adjusting a process output value
US20060129266A1 (en) * 2004-12-10 2006-06-15 The Procter & Gamble Company Method of controlling tension in a web
US7092781B2 (en) 2004-12-10 2006-08-15 The Procter & Gamble Company Method of controlling tension in a web

Also Published As

Publication number Publication date
CA968870A (en) 1975-06-03
JPS48100362A (enrdf_load_stackoverflow) 1973-12-18
JPS5021430B2 (enrdf_load_stackoverflow) 1975-07-23
ZA73828B (en) 1973-11-28
BE796056A (fr) 1973-08-28

Similar Documents

Publication Publication Date Title
USRE25075E (en) Rolling mills
US3457747A (en) Rolling mills
US2883895A (en) Rolling mill thickness control system
GB1292845A (en) Predictive gauge control method and apparatus with adaptive plasticity determination for metal rolling mills
US3768286A (en) Interstand tension regulator for a multistand rolling mill
GB1248978A (en) Predictive roll-force gauge control method and apparatus for metal rolling mills
US3613419A (en) Rolling mill automatic gauge control with compensation for transport time
US4011743A (en) Stand speed reference circuit for a continuous tandem rolling mill
US4087859A (en) Apparatus for measuring and controlling interstand tensions of continuous rolling mills
US4079609A (en) Control system for multiple stage reducing apparatus
US3811304A (en) Looper controlled rolling mill
US4408470A (en) Procedure and device for rolling metals without stress
US3566639A (en) Gage control for multistand rolling mill
US4398254A (en) Method for controlling strip thickness in strip mill
US3688532A (en) Control system for tandem rolling mill based on the constant volume principle
US3762195A (en) Thickness control apparatus for rolling mill
US2462233A (en) Motor control system
GB1224713A (en) Improvements in or relating to rolling mill control systems
US3212310A (en) Automatic gauge and tension control system
US3765203A (en) Automatic gauge control by tension for tandem rolling mills
EP0455382B1 (en) Method for controlling gage in a metal rolling mill
US3869892A (en) Feed forward gauge control system for a rolling mill
GB898613A (en) Automatic control system for continuous strip mill
US4286447A (en) Method and apparatus for automatic gauge control system for tandem rolling mills
US4063438A (en) Method of controlling tandem rolling mills

Legal Events

Date Code Title Description
AS Assignment

Owner name: AEG WESTINGHOUSE INDUSTRIAL AUTOMATION CORPORATION

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:WESTINGHOUSE ELECTRIC CORPORATION;REEL/FRAME:005424/0551

Effective date: 19900313