US3331229A - Process and apparatus for eliminating the excentricity effect of rollers in hot and cold rolling mills for metal sheets - Google Patents

Process and apparatus for eliminating the excentricity effect of rollers in hot and cold rolling mills for metal sheets Download PDF

Info

Publication number
US3331229A
US3331229A US3331229DA US3331229A US 3331229 A US3331229 A US 3331229A US 3331229D A US3331229D A US 3331229DA US 3331229 A US3331229 A US 3331229A
Authority
US
United States
Prior art keywords
rolls
excentricity
rolling
value
roll
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
Other languages
English (en)
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.)
Publication date
Application granted granted Critical
Publication of US3331229A publication Critical patent/US3331229A/en
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
    • B21B37/58—Roll-force control; Roll-gap control
    • B21B37/66—Roll eccentricity compensation systems

Definitions

  • This invention relates to a process and apparatus for eliminating the excentricity effect of the rolls in hot and cold rolling mills for metal sheets and strips, and more particularly to a process and apparatus of this type in which a separate recording or registering device is associated with the rolling mill for scanning the excentricity of the rolls and for transmitting to roll adjusting devices signals corresponding to the excentricity characteristics.
  • the present invention provides a process and apparatus for eliminating the effect of excentric rolls which comprises the following steps: the excentricity characteristics of each roll are registered in its travel symmetrically to the rolling path or plane; an algebraic sum is produced from the measured excentricity values which vary as a rule between a maximum and a minimum per rotation, that is to say the addition of the maximum value of one roll and the minimum value of the other roll would produce the sum zero; this sum, which is a measurement of the rolling gap changes due to excentricity of the rolls, is superimposed as disturbance value or factor upon the control system-if desired also with a reversal of the existing signin the sense that the control values of the control system which arise due to the excentricity of the rolls from the changes in the rolling pressure or due to expansion are compensated or balanced out.
  • a rolling stand which, independent to a large extent from its own rigidity, provides a constant rolling gap-as far as varying properties of the rolling stock cause the controlling action-and which permits simultaneously a softness of the stand which absorbs the excentricity of the rolls.
  • the present invention also shows a way to adjust the excentricity of the rolls in a positive manner in order to eliminate also in existing rigid stands the influence of excentric rolls, or to produce in new structures the best possible effect from the start.
  • the disturbance value and the control or adjustment value to be compensated and having a wrong signal correspond in the absolute magnitude, and as both values are functions of the sum of the excentricities of both rolls active in the rolling gap,
  • the adjustment value is for example +1.
  • the disturbance value is originally 1, in order to cancel the adjustment value.
  • the negative disturbance value is doubled to 2 the compensation produces a negative adjustment value of l, that is to say, the adjustment value which was originally correct in its order value, has now the correct sign.
  • the product resulting from this process is a sheet or strip which is free of periodically arising thickened and thinned portions which are characteristic traces of the effect of excentric rolls.
  • a construction may be provided in which the exccntricity of the rolls during operation may be registered directly at the rolls, and relative to the insert members, appro riately at the edges of the roll surface or on the side. so that the deflection of the roll does not enter into the measured values.
  • the unavoidable vibrations in the rolling mill operation as well as the emulsions adhering to the rolls would create substantial difficulties to a dependable measurement during a cold rolling operation in view of the roll beat of only a few hundreds of a millimeter.
  • the excentricity may amount to several tenths of a millimeter, it is easier to measure the excentricity at the rolls themselves.
  • the invention provides an arrangement for carrying out the process according to this invention which includes a copying or scanning device installed separately from the rolling stand and provided with an indicator element or template associated with each roll and rotating synchronously therewith, and on which the excentricity of the rolls established beforehand on a grinding lathe.
  • each indicator element cooperating with a scanner whose functional translation corresponds to the measurement of the excentricity of the rolls symmetrically to the rolling line, and in which a device for compiling the algebraic sum of the scanned values as well as a compensator are provided, in which the measuring.
  • control or adjustment values on the one hand and the disturbance value derived from the summer on the other hand are connected in opposition or whereby the desired control value is regulated.
  • FIG. 1 shows a four-high frame with the diagrammatic control arrangement and the scanning apparatus tracing the excentricity of the rolls and FIGS. 2 and 3 show two modifications of the scanning apparatus for transmitting the excentricity of a roll to a template subject to electronic scanning.
  • FIGURE 1 shows a normal stand or frame having cast posts, and according to a known construction elastic pressure members 3 in the form of a diaphragm are arranged between the upper chuck 1 and the adjusting spindles 2 for providing a coarse adjustment.
  • the pressure members 3 may be placed under tension by means of hydraulic expansion pistons 4 before commencing the rolling operation.
  • the tension pressure is transmitted over pressure indicator boxes 5 into the posts 6 to put them also under a pretension.
  • a hydraulic pressure of high power is directed against expansion pistons 4 from pressure intensifier 8 through line 7.
  • the pressure intensifier 8 is connected over line 9 to a control slide valve 10.
  • the line 11 leads from slide valve 10 to a pressure source and line 12 is the return line.
  • the piston rod 13 of the slide valve is regulated by conventional adjusting means (not shown ⁇ located in the regulator 14.
  • the measured pressure value of pressure measuring box 5 is introduced into regulator 14 through line 15.
  • This value comprises the sum of the rolling pressure PR and the hydraulic tension force PHy of expansion piston 4.
  • the regulation is directed to the constancy of the sum PR-t Ph'y, i.e. to the constancy of the tension in the elastic pressure members 3 and the stand posts 6. which amounts to a constant rolling gap.
  • the rolling pressure PR increases it is accordingly necessary that the hydraulic tension force PH or the specific pressure in the lines 7 be reduced.
  • This control effect has the wrong sign in the case where the rolling pressure increases due to the excentricity of the rolls because in that case the value PHy would have to be increased or at least should not be decreased.
  • the same problem exists also in the case of mechanically adjusted rolling stands where the rolls are set closer when the rolling pressure increases.
  • an electriohydraulic control arrangement is preferable due to its shorter reaction time and because it is less sensitive to frequent operating changes.
  • FIGURE 1 A suitable copying device is shown in FIGURE 1 and is provided with electrically scanned indicator elements or templates. These elements consist of two excentric discs 35, 36 whose excentricity represents the excentricity or non-roundness of the rolls in an enlarged scale, and they rotate on electrically operated shafts 18, 19 synchronously and in a phase position corresponding with the excentricity of the rolls to which they are connected.
  • a scanning device in the form of a differential transformer 37, 38 is associated with each excentric disc and the iron core 370, 38a respectively of each transformer 37, 38 is provided with a scanning roller 37!), 38b which is urged against the circumference of the concentric discs.
  • the plane 39 which passes through the axes of rotation of excentric discs 35, 36 corresponds to the vertical rolling plane of the rolling stand.
  • the two scanning rollers 37b, 38b engage the excentric discs symmetrically to the imaginary rolling line 40 but displaced in a direction opposite to the direction of rotation of the discs and in a common vertical plane 41.
  • This displacement has the purpose of taking into account a longer response time of the compensation control with regard to a normal regulation of the roll stand.
  • the differential transformers 37 and 38 furnish at the secondary winding various voltages which may have different signs depending on whether a maximum or a minimum of excentrieity is present at a. scanning roller.
  • the measured electrical values are transmitted over lines 42, 43 and over potentiometers 44, 45 to a summer 46 in which the algebraic sum of the scanning values is formed.
  • This value is transmitted as disturbance value over an amplifier 47 and line 48 to a compensator 49 into which the values from the pressure measuring box 5 are conducted through line 15 in order to compensate these two measurement values before they enter the regulator 14 as far as any rolling pressure changes due to the excentricity of the rolls is concerned.
  • the operation of the scanning device according to FIG- URE 2 is as follows: after the positioning of one or both of the rolls whose excentricity has been determined previously and been indicated on the rolls, the excentricity of the discs 36, 35 is set in each instance to the same phase position relative to the excentricity of the corresponding roll before their shafts are coupled to the synchronous drive. It is necessary to take into account that the exeentricity of both rolls 16, 17 may be different, for example in roll 16 it may be only 3 mm. in contrast to the other roll 17 which may be mm. In order to take into account this difference in the excentricity or nonroundness of the respective rolls, one could insert after each roll grinding operation newly adapted excentric discs.
  • the amount of beat or excentricity of the rolls may be different during operation in the rolling mill, that is to say during loading of the rolls, from what it was before on the grinding lathe measured with a test watch. There may be tensions in the rolls which disappear after a few rotations.
  • potentiometers 44, 45 it is possible to adjust the scanning device in such a way that the measuring device 52 does not indicate any pressure variations. This adjusting process is carried out best when the rolls are positioned with their excentricities in the same phase, because only the largest and most easily recognizable excentricities appear at the measuring device 52 when the balance is not correct.
  • the compensation adjustment is still not set to the best possible effect as only the major values are cancelled from the stand adjustment in order that the rolls do not move closer when the excentricity 16a and 17a come into the area of the rolling gap.
  • the elastic pressure members 3 have a favorable effect in this respect because they make the roll stand soft, so that the upper roller 16 may move upwardly as the excentric areas of the rolls approach.
  • the rolling stand control values which are derived from the rolling stock may be superimposed on the compensation control, so that the movement of the indicator hands of the measuring devices 52 and 53 give an indication for regulating the excentricity of the rolls only from time to time, when the excentricities are of. equal phase and their influence is at a maximum.
  • the electrical disturbance value it is possible to connect the electrical disturbance value also against the control value or the adjusting value in the regulator 14, or it may serve to regulate the control-nominal value.
  • a variation of the regulation setting by changing the nominal value amounts to a change of the roll gap.
  • FIGURES 2 and 3 it will be seen that they illustrate two possibilities of adjusting the excentricity of the rolls with respect to indicator devices of a special type.
  • the polished roller 54 which is mounted in the roller pins, is scanned, while being rotated, by means of a testing watch 55, before it is built into the stand.
  • the testing watch produces a measuring current corresponding to the deflections of the watch hand, and these currents are fed, as seen in FIGURE 1, to a recording instrument having a rotating disc 56.
  • the roll and the disc rotate synchronously.
  • the recording stylus shows virtually the cross-section through the roll in the perpendicular scanning plane of the roll by the line 57, which illustrates thus an excentricity.
  • the disc 56 may be employed directly as an indicator element in a scanning device in that the line 57 is scanned photoelectrically or magnetically when the stylus is suitably constructed.
  • the measuring circuits travel from the measuring clock 55 to a mixer stage 58 into which a sound frequency is introduced at 59.
  • the mixer frequency is transcribed onto an endless tape 60 in which one rotation corresponds to one or to a multiple of the rotation of the roll.
  • the tape is provided like a film tape with perforations into which the teeth of the driving discs 61 and 62 penetrate and represents also an indicator or template for a scanning device from which the excentricity of a roll may be registered through a magnetic head.
  • an illuminated film strip may be used as indicator or template element. in which case the scanning devices would operate in an electro-optical manner.
  • the modified copying or scanning devices illustrated in FIGURES 2 and 3 do not present any difficulties in their construction, as only known elements and known electronic circuits are employed, and for this reason a detailed showing of the electronic system of such copying devices is not made here.
  • the invention is applicable independently of whether the rolling stand has been given a soft construction due to the presence of a rapidly responding control arrangement or not.
  • the necessity for eliminating the effect of excentric rolls in pressure regulated roll stands is particularly obvious, it is within the scope of this invention to apply the compensation adjustment also in stands which are not adjusted at all, or which are adjusted by means of thickness measuring devices.
  • the disturbance value which has not been doubled that is to say the signal obtained by any means, which is proportional to the given algebraic sum of the excentricity of the rollers, is conducted as control value to the adjusting motors, or to any type of hydraulic adjusting device, under certain circumstances also to a device for equalizing the weight of the rolls, which must be designed to allow a periodically controlled elongation of the stand corresponding to the cxcentricity, in order to regulate the distance of the roll axes inversely to the rolling gap changes to be expected from the excentricity of the rolls.
  • Apparatus for eliminating the effect of excentric rolls in hot and cold rolling mills for metal sheets and strips comprising in combination support means for said rolls,
  • Apparatus for eliminating the effect of excentric rolls in hot and cold rolling mills for metal sheets and strips comprising in combination support means for said rolls,
  • fluid operated piston means for tensioning said support means to adjust the rolling gap
  • said regulator means actuating said valve means in response to said control value received from said compensating means.
  • Apparatus for eliminating the effect of excentric rollers in hot and cold rolling mills for metal sheets and strips comprising in combination support means for said rolls,
  • excentricity registering means including (a) template means rotating synchronously with said rolls and coupled thereto in a phase position corresponding to the excentricity of said rolls,
  • transfer means for feeding said tension value and said excentricity value to said compensating means
  • said regulator means actuating said valve means in response to said control value received from said compensating means.
  • each scanning means is connected to a transformer and wherein a potentiometer is connected between said transformer and said summer means.
  • excentricity registering means include an excentricity measuring instrument connected to each roll and adapted to generate an electric current
  • a recording device having a disc rotatable synchronously with the roll. to indicate its excentricity.
  • said registering means include an excentricity measuring instrument connected to each roll and adapted to generate an electric current
  • a mixer device connected to said measuring instrument and receiving a sound frequency
  • a recorder device adapted to receive the mixer frequency from said recording head.
  • a process for eliminating the effect of excentric rolls in hot and cold rolling mills for metal sheets and strips comprising producing a signal proportional to the algebraic sum of the excentric values of said rolls,

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Metal Rolling (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
US3331229D 1962-08-29 Process and apparatus for eliminating the excentricity effect of rollers in hot and cold rolling mills for metal sheets Expired - Lifetime US3331229A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEV22969A DE1236452B (de) 1962-08-29 1962-08-29 Verfahren und Vorrichtung zum Beseitigen des Einflusses unrunder Walzen in Warm- und Kaltwalzwerken fuer Bleche und Baender

Publications (1)

Publication Number Publication Date
US3331229A true US3331229A (en) 1967-07-18

Family

ID=7580226

Family Applications (1)

Application Number Title Priority Date Filing Date
US3331229D Expired - Lifetime US3331229A (en) 1962-08-29 Process and apparatus for eliminating the excentricity effect of rollers in hot and cold rolling mills for metal sheets

Country Status (6)

Country Link
US (1) US3331229A (enrdf_load_stackoverflow)
AT (1) AT239171B (enrdf_load_stackoverflow)
BE (1) BE636339A (enrdf_load_stackoverflow)
DE (1) DE1236452B (enrdf_load_stackoverflow)
GB (1) GB1020775A (enrdf_load_stackoverflow)
LU (1) LU44307A1 (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3460365A (en) * 1966-02-21 1969-08-12 Davy & United Eng Co Ltd Rolling mills
US3543549A (en) * 1967-11-21 1970-12-01 Davy & United Eng Co Ltd Rolling mill control for compensating for the eccentricity of the rolls
US3580022A (en) * 1968-11-12 1971-05-25 Youngstown Sheet And Tube Co Rolling mill including gauge control
US3683653A (en) * 1971-02-22 1972-08-15 Gen Electric Motor drive system for rolling mill
US3795124A (en) * 1970-06-12 1974-03-05 Spidem Ste Nle Method of detecting and compensating for defects on rolling mill rolls and means for applying this method
US3881335A (en) * 1974-03-07 1975-05-06 Westinghouse Electric Corp Roll eccentricity correction system and method
US4521859A (en) * 1982-10-27 1985-06-04 General Electric Company Method of improved gage control in metal rolling mills
CN102284510A (zh) * 2011-07-14 2011-12-21 莱芜钢铁集团有限公司 一种防止轧机末机架空载轧辊啃伤的方法

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE592289A (enrdf_load_stackoverflow) * 1959-06-27

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3460365A (en) * 1966-02-21 1969-08-12 Davy & United Eng Co Ltd Rolling mills
US3543549A (en) * 1967-11-21 1970-12-01 Davy & United Eng Co Ltd Rolling mill control for compensating for the eccentricity of the rolls
US3580022A (en) * 1968-11-12 1971-05-25 Youngstown Sheet And Tube Co Rolling mill including gauge control
US3795124A (en) * 1970-06-12 1974-03-05 Spidem Ste Nle Method of detecting and compensating for defects on rolling mill rolls and means for applying this method
US3683653A (en) * 1971-02-22 1972-08-15 Gen Electric Motor drive system for rolling mill
US3881335A (en) * 1974-03-07 1975-05-06 Westinghouse Electric Corp Roll eccentricity correction system and method
US4521859A (en) * 1982-10-27 1985-06-04 General Electric Company Method of improved gage control in metal rolling mills
CN102284510A (zh) * 2011-07-14 2011-12-21 莱芜钢铁集团有限公司 一种防止轧机末机架空载轧辊啃伤的方法

Also Published As

Publication number Publication date
AT239171B (de) 1965-03-25
GB1020775A (en) 1966-02-23
LU44307A1 (enrdf_load_stackoverflow) 1963-10-22
BE636339A (enrdf_load_stackoverflow)
DE1236452B (de) 1967-03-16

Similar Documents

Publication Publication Date Title
US3850015A (en) Roll gap detection
US3331229A (en) Process and apparatus for eliminating the excentricity effect of rollers in hot and cold rolling mills for metal sheets
US4400957A (en) Strip or sheet mill with improved regulating device and method
US3358485A (en) Measuring and controlling gap between rolls
US4691547A (en) Rolling mill strip thickness controller
CA2182832C (en) Method of compensating forces in roll stands resulting from horizontal movements of the rolls
US3581536A (en) Apparatus for sensing the unstressed shape of a thin strip subjected to high tensile stress
US3543549A (en) Rolling mill control for compensating for the eccentricity of the rolls
US3756050A (en) Method and apparatus for controlling metal strip shape
US3714806A (en) Drift corrector for transducers
US3208251A (en) Rolling mill control system
US2332288A (en) Compensating potentiometer
US3355924A (en) Control of deflection in rolling mills and the like
US4648257A (en) Rolling mill eccentricity compensation using actual measurement of exit sheet thickness
US4656854A (en) Rolling mill eccentricity compensation using measurement of sheet tension
GB1013267A (en) Method and apparatus for reducing the thickness of strip material
US3475935A (en) Control apparatus and system for strip rolling
US4036041A (en) Gage control system for rolling mill
US3791204A (en) Rolling mill force measuring apparatus
JPH07508222A (ja) 帯板圧延における平面度制御
US4483165A (en) Gauge control method and apparatus for multi-roll rolling mill
GB1072866A (en) Rolling mill control apparatus
GB898613A (en) Automatic control system for continuous strip mill
US4149395A (en) Method and apparatus for correcting camber in rolled metal workpiece
US3517531A (en) Rolling mill gage control actuator system