CA1038662A - Method for controlling flatness of metal sheet in rolling - Google Patents
Method for controlling flatness of metal sheet in rollingInfo
- Publication number
- CA1038662A CA1038662A CA232,697A CA232697A CA1038662A CA 1038662 A CA1038662 A CA 1038662A CA 232697 A CA232697 A CA 232697A CA 1038662 A CA1038662 A CA 1038662A
- Authority
- CA
- Canada
- Prior art keywords
- sheet
- rolling
- flatness
- rolls
- mill rolls
- 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
Links
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
- B21B37/28—Control of flatness or profile during rolling of strip, sheets or plates
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Control Of Metal Rolling (AREA)
- Metal Rolling (AREA)
- Length Measuring Devices With Unspecified Measuring Means (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method is disclosed for controlling the flatness of a metal sheet in rolling through rolling mill rolls. It involves the use of a flatness controller which comprises several rollers with a barrel length shorter than the width of the sheet. The flatness controller is arranged downstream of the mill rolls. The tension distribution in the sheet during rolling of the sheet through the rolling mill rolls in the width direction is changed by vertically moving some or all of the rollers forming the flatness controller and thereby giving vertical displacement to the corresponding part of the sheet during rolling. This thereby increases the draft in that part of the sheet during rolling. In order effectively to change the tension distribution, an auxiliary roller is arranged, if necessary, downstream of the mill rolls and at a location more distant from the mill rolls than the flatness controller rollers.
A method is disclosed for controlling the flatness of a metal sheet in rolling through rolling mill rolls. It involves the use of a flatness controller which comprises several rollers with a barrel length shorter than the width of the sheet. The flatness controller is arranged downstream of the mill rolls. The tension distribution in the sheet during rolling of the sheet through the rolling mill rolls in the width direction is changed by vertically moving some or all of the rollers forming the flatness controller and thereby giving vertical displacement to the corresponding part of the sheet during rolling. This thereby increases the draft in that part of the sheet during rolling. In order effectively to change the tension distribution, an auxiliary roller is arranged, if necessary, downstream of the mill rolls and at a location more distant from the mill rolls than the flatness controller rollers.
Description
t 03B662 This invention relates to a method for controlling the flatness of a metal sheet such as, for example, steel plate and sheet, in particular a thin steel sheet defective in flatness, during rolling.
A metal sheet such as, for example, steel plate and sheet, in-particular a thin steel sheet, is usually produced by rolling a material through rolling mill rolls. ln this case, the sheet in rolling is elon-gated in the rolling direction while being reduced in cross section into a sheet with a reduced thickness. This elongation of the sheet in rolling in the rolling direction depands upon the draft (i.e., thickness at the roll entry - thickness at the roll exit / thickness at the roll entry).
The distribution of such elongation in the width direction is determined by the thickness distribution in the width direction before rolling and the thickness distribution in the width direction after rolling. The above-mentioned thickness distribution in the width direction after rolling is influenced by deformation of rolling mill rolls such as, for example, (a) elastic deformation of the mill rolls, (b) thermal expansion of the mill rolls due to the heat input from the sheet in rclling to the mill rolls, (c) wear of the mill rolls resulting from friction between the sheet in rolling and the mill rolls.
For such reasons, when the elongation of the sheet in rolling in the rolling direction is not uniform and there occur differences in said elongation in the width direction, compressive and tensile residual stresses are produced in the finished sheet in the rolling direction; that is, since a small thickness is obtained in the case of a large draft and a large thickness is obtained in the case of a small draft, compressive stresses remain in the part of the finished sheet with a small thickness and tensile stresses remain in the part of the finished sheet with a large thickness.
When these residual stresses exceed a certain limit, the finished sheet undergoes deformation out of original plane, resulting in a phenomenon called "buckling". This is generally called the defective flatness of finished sheet.
Some types of buckling, which will be described in greater detail hereinafter are center buckling, quarter buckling and wavy edge. Thes~
- 1- ~.:.. , states of defective flatness of the finished sheet lead to troubles in using the apparatus in the subsequent procedural steps and to a decreased quality of products.
With a view to precluding the occurrence of such defective flatness of finished sheet, the following representative methods have been proposed:
(1) Roll bending method
A metal sheet such as, for example, steel plate and sheet, in-particular a thin steel sheet, is usually produced by rolling a material through rolling mill rolls. ln this case, the sheet in rolling is elon-gated in the rolling direction while being reduced in cross section into a sheet with a reduced thickness. This elongation of the sheet in rolling in the rolling direction depands upon the draft (i.e., thickness at the roll entry - thickness at the roll exit / thickness at the roll entry).
The distribution of such elongation in the width direction is determined by the thickness distribution in the width direction before rolling and the thickness distribution in the width direction after rolling. The above-mentioned thickness distribution in the width direction after rolling is influenced by deformation of rolling mill rolls such as, for example, (a) elastic deformation of the mill rolls, (b) thermal expansion of the mill rolls due to the heat input from the sheet in rclling to the mill rolls, (c) wear of the mill rolls resulting from friction between the sheet in rolling and the mill rolls.
For such reasons, when the elongation of the sheet in rolling in the rolling direction is not uniform and there occur differences in said elongation in the width direction, compressive and tensile residual stresses are produced in the finished sheet in the rolling direction; that is, since a small thickness is obtained in the case of a large draft and a large thickness is obtained in the case of a small draft, compressive stresses remain in the part of the finished sheet with a small thickness and tensile stresses remain in the part of the finished sheet with a large thickness.
When these residual stresses exceed a certain limit, the finished sheet undergoes deformation out of original plane, resulting in a phenomenon called "buckling". This is generally called the defective flatness of finished sheet.
Some types of buckling, which will be described in greater detail hereinafter are center buckling, quarter buckling and wavy edge. Thes~
- 1- ~.:.. , states of defective flatness of the finished sheet lead to troubles in using the apparatus in the subsequent procedural steps and to a decreased quality of products.
With a view to precluding the occurrence of such defective flatness of finished sheet, the following representative methods have been proposed:
(1) Roll bending method
(2) Asymmetrical roll bending method
(3) Thermal crown control method
(4) Flatness control method using rolling oil.
These conventional methods and disadvantages thereof are described below.
(1) Roll bending method:
This is a method for correcting a sheet defective in flatness in rolling over the entire width which comprises, providing roll neck ends of work rolls and back-up rolls with pressure applying devices such as, for example, hydraulic cylinders and giving forced bending to the work rolls and/or the back-up rolls thereby cha~ging the roll profiles. However, as the diameter of the rolls becomes larger, it becomes more difficult to bend the work rolls and the back-up rolls and considerably large pressure applying devices (bending devices) are required, especially for the back-up rolls which have a larger roll diameter. In addition, when only the work rolls are bent, the bending effect is limited to the ends of the sheet in rolling. Therefore, in this case, this method is not effective in preclud-ing the occurrence of center buckling.
(2) Asymmetrical roll bending method:
This is a method for correcting a sheet defective in flatness in rolling over the entire width which comprises applying an asymmetrical rolling force to the sheet in rolling in the width direction (see, for example, Japanese Patent Provisional Publication No. 10,855/74). More specifically, pressures are applied to neck ends of the work rolls in a certain stand, locally to correct the defective flatness of the sheet in rolling. Then, pressures are applied to the left-hand roll neck ends of the work rolls in the following stand, to correct the defective flatness of the other part of said sheet in rolling, whereby the flatness of said sheet in rolling is controlled over the entire width. In this method, rolling forces applied asymmetrically in the width direction to the sheet in rolling, pose a problem in the stability of threading between stands.
(3) Thermal crown control method: ¦
The unbalance between the heat input from the sheet in rolling to ~-~
~,~
the rolling mill rolls and the heat output from the rolls caused by radiation gives rise to unbalanced temperature distribution within the rolls, as a result of which urlbalanced thermal expansion occurs in the rolls, thus changing the profileQ of the rolls. (This phenomenon is called thermal crown.) The thermal crown control method for correcting a sheet defective in flatness in rolling over the entire width comprises, spraying lubricating oil over the work rolls and back-up rolls from lub- r ricating oil sprays and changing the capacity of the lubricating oil for cooling the work rolls and the back-up rolls in the axial direction of the rolls (i.e., in the width direction of the sheet in rolling) by regulating the amount of spray of the lubricating oil, thereby controlling the dis- _ tribution of the amount of the above-mentioned tbermal crown in the axial direction of the rolls (see, for example, Japanese Patent Publication No.
49-9031, March 1, 1974. In this method, since the temperature of lubricating oil is relatively high, the cooling capacity of lubricating oil is limited to a certain range. Moreover, changes in thermal crown are not always proportional to changes in the cooling capacity of lubricating oil. In addition, as it takes time for changes in thermal crown to respond to .
changes in the cooling capacity of lubricating oil, it is not feasible L
to control the flatness of the sheet in rolling in a short time.
(4) Flatness control method using rolling oil:
This is a method for correcting a sheet defective in flatness in rolling over the entire width which comprises increasing or decreasing in 3~ the width direction the friction between the rolling mill rolls and the sheet in rolling by increasing or decreasing the amount of rolling oil in the width direction, thereby changing the distribution of rolling force in the width direction (see, for example, Japanese Patent Provisional Pub-B -~-`" 103~662 lication Nos. 23.157/74 and 28,555/74). Although this method is effec-tive in hot rolling, it does not seem to be as effective in cold rolling.
As mentioned above, although several methods have been proposed for precluding the occurrence of finished sheets with defective flatness by controlling the flatness of the sheet during rolling, satisfactorily effective methods have not as yet been developed.
Therefore, an object of one aspect of this invention is to provide, in rolling a metal sheet through rolling mill rolls, a method of greatly minimizing or even precluding the occurrence of finished metal sheet with defective flatness by controlling the flatness of the sheet during rolling.
An object of a principal aspect of this invention is to provide a simple and practical method of greatly minimizing or even precluding the occurrence of finished metal sheet with defective flatness by giving a desired change to the tension distribution in the sheet in rolling inthe width direction, thereby controlling the flatness of the sheet during rolling.
By one broad aspect of this invelltion, a method is provided for controlling the flatness of a metal sheet during rolling of the sheet through rolling mill rolls, which comprises the steps of:
arranging a plurality of flatness controlling rollers, each with a barrel length shorter than the width of said sheet, downstream of said rolling mill rolls, in a fashion adjacent one another with their axial direction substantially perpendicular to the direction of rolling of the sheet to extend transversely across the width of thc sheet, said pluralitv of flatncss controlling rollers being selectively individllal]y vertically movable; and changing the tension distribntion in said sheet during rolling tllereof in the width direction by moving at least one of said plurality of rollers relative to said sheet to give a vertical displace-ment to the corresponding part of said sheet during rolling, thereby increasing the draft in said par-t of said sheet during rolling.
By one variant, the.metnod includes the step of arranging an auxiliary undriven roller downstream of said rolling mill rolls and at a location more distant from said rolling mill rolls than said plurality of flatness controlling rollers, thereby aiding said flatness controlling rollers to change the tension distribution in said sheet effectively.
By a preferred variant, the flatness controlling rollers are located below said sheet and are selectively raised to change said tension distribution in said sheet during rolling.
By yet another variant, the vertical displacement given to said metal sheet during rolling by said flatness controlling rollers~ is at least 5mm.
Of the accompanying drawings:
-4a-~03~62 Figures l(a), l(b), l(c), l(d), 2(a), 2(b), 2(c), 2(d), 3(a), 3(b), 3(c) and 3(d) are schematic drawings of a finished sheet with defective flatness, wherein figures (a) are perspective views of a finished sheet with defective flatness, figures (b) are the sectional views of the finished sheet in the width direction, figures (c) are graphs which show the tension distribution in the finished sheet in the width direction, and figures (d) are graphs which show the thickness distribution of the finished sheet in the width direction;
Figures 4 to 6 are schematic drawings which illustrate some con-ventional methods of precluding the occurrence of finished sheet with defective flatness;
Figure 7 is a schematic drawing which illustrates the effect oftension on rolling force;
Figures 8 to 10 are schematic drawings which give an outline of the method of embodiments of an aspect of this invention;
Figure ll(a) is a perspective view which illustrates the state of displacement of a sheet; Figure ll(b) is a graph which illustrates the amount of vertical displacement of the sheet in the width direction (i.e., the rise of the sheet); and Figure ll(c) is a graph which illustrates the tension distribution generated in the sheet during the displacement;
and Figure 12(a) shows a curve which represents the relation between the distance in the width direction and the tension distri~ution in a sheet; and Figure 12(b) gives a curve which indicates the relation between the distance in the width direction and the thickness distribution of said sheet.
As mentioned above, Figures 1 to 3 show the relation between the thickness distribution in the width direction after rolling in the case of a uniform thickness at the roll entry and the state of defective flat-ness of the finished sheet, resulting from the thickness distribution.
The state of defective flatness as shown in Figure 1 is called center buc~ling; the state of defective flatness as shown in Figure 2 is celled quarter buckling; and the state of defective flatness as shown in Figure 3 is called wavy edge. 103~6Z
Referring to Figures l(a) - (d), it is seen that the sheet S
has defective flatness i.e., center buckling. As shown in Figure l(b) the cross-section of the sheet S is of double concave appearance. As shown in Figure l(c) the tension distribution across the width of the sheet varies from stretching tension at the edges E of the sheet, to compression tension in the central areas C of the sheet. Similarly, as shown in Figure l(d), the thic~ness distribution across the width of the sheet varies from thick areas at the edges E of the sheet, to thinner areas in the central areas C of the sheet.
Referring to Figures 2(a) - (d), it is seen that the sheet S has defective flatness i.e., quarter buckling. As shown in Figure 2(b) the cross-section of the sheet S is of wavy appearance, i.e., it includes a thick region at the transverse line of symmetry and both right side and left side double concave shapes. As shown in Figure 2(c) the tension distribution across the width of the sheet varie8 in the form of a sine wave, i.e., it has stretching tension at the edges E and at the transverse line of symmetry L, and compression tension in the central areas between the edges E and the line of symmetry L. Similary, as shown in Figure 2(d), the thickness distribution across the width of the sheet varies in the form of a since wave, with thick areas at the edges E and at the line of symmetry L, and thinner areas C between the thick portions.
Referring to Figures 3(a) - (d), it is seen that the sheet S has defective flatness, i.e., wavy edge. As shown in Figures 3(b), the cross-section of the sheet S is of double convex appearance. As shown in Figure 3(c) the tension distribution across the width of the sheet varies from compression tension at the edges E, to stretching tension at central areas C. Similarly, as shown in Figure 3(d), the thickness distribution across the width of the sheet varies from thin areas at the edges E to thicker areas at the central areas C.
As shown in Figure 4 providing the roll neck ends 1 and 2 of work rolls 1 and back-up rolls 2 with pressure applying devices, such as, for example, hydraulic cylinders H and giving forced bending to work rolls 1 ~038662 and/or back-up rolls 2, thereby changing the roll profiles. However, as the sixe of the diameter of work rolls 1 and back-up rolls 2 becomes larger, it becomes difficult to bend work rolls 1 and back-up rolls 2 and considerably large pressure applying devices (bending devices) H are required especially for back-up rolls 2 which have a larger roll diameter.
In addition, when only the work rolls 1 are bent, the bending effect is limited to the ends of the sheet S in rolling.
As shown in Figure 5(a), pressures are applied as indicated by the arrows A to the roll neck ends at the right hand side of work rolls 1 in a certain stand, locally to correct the defective flatness of the sheet S
in rolling. Then, as shown in Figure 5(b), pressures are applied as indicated by the arrows A to the roll neck e~ds 1 at the left hand side of work rolls 1 in the following sLand, to correct the defective flatness of the other part of sheet S in rolling, whereby the flatness of sheet S
in rolling is controlled over the entire width.
As shown in the side elevation and plan view in Figures 6(a) and (b), respectively, lubricating oil is sprayed over work rolls 1 and back-up rolls 2 from lubricating oil sprays through nozzles 3. The capacity of the lubricating oil for cooling said work rolls 1 and back-up rolls 2 in the axial direction thereof, (i.e., in the width direction of the sheet S in rolling) is changed by regulating the amount of spray of lubricating oil, through nozzles 3 thereby controlling the distribution of the amount of the thermal crown in the axial direction of the rolls 1 and 2.
As is well known, according to Dr. D.R. Bland and Dr. H. Ford, the following equations stand with regard to the rolling of a metal sheet through rolling mill rolls:
P = R' r ~P d~ + R'J O P d~
P = km~l -qf/km)h/h2e f~
p km(l qb/ m) / 1 Where, P : Rolling load, P : Rolling pressure acting on the part from the neutral point ~03866Z
~- to the roll bite exit. (The neutral point is defined as the point where the roll peripheral speed corresponds to the forward speed of the sheet in rolling. The ro'l bite is the contact surface between the rolls and the sheet in rolling.), P : Rolling pressure acting on the part rom the neutral point to the roll bite entry, k : Mean dcformation resistance of the sheet in rolling, m qf : Front ~ension applied to the sheet in rolling (i.e., tension on the roll exit s~de), qb : Back tension applied to the sheet in rolling (i.e., tension on the roll entry side), h : Thickness of the sheet in rolling at an arbitrary point within the roll bite, hl : T~ic~ness of the sheet in rolling at the roll entry, h2 : Thickness of the sheet in rolling at the roll exit, O : Roll center angle comprising the part of the roll bite between bite exit and the position corresponding t to thickness h, t ~ : Roll center angle comprising the part of the roll bite between the neutral point and the bite exit, : Roll center angle comprising the part of the roll bite between the bite entry and the bite exit, R' : Flattened radius of roll, : Coefficient of friction between the sheet in rolling and the rolls, H : 2 ~ tan ~ 0 , and ~11 : H at the roll bite entry.
Further, Dr. A.J.F. ~lacQueen has experimentally confirmed the 3() validity of the following equations holding between the factors:
T 0.16 TF + 0.32 TB
Where, P : Rolling load, P : Rolling load required when no tension is applied to the sheet in rolling, PT : Amount of decrease in rolling load when tension is applied to the sheet in rolling, TF : Front tension applied to the sheet in rolling (i.e., tension on the roll exit side), and TB : Back tension applied to the sheet in rolling (i.e., tension on the roll entry side).
As is apparent from the above-mentioned equations, when tension i8 applied to the sheet in rolling, the same effect is obtained as in the cS~se where the deformation resistance of said sheet in rolling decreases, and accordingly, the rolling force on the rolling mill rolls decreases.
When the rolling force on the rolling mill rolls decreases, the thickness of the sheet in rolling is reducet by the elastic teformation of the rolling mill if the mill setting is kept unchanget. It is ascertained that these relations can be appliet for gage control of finishet sheets such as, for example, thin steel sheets.
The foregDing i8 applicable in a case where the tension applied to the sheet in rolling varies in the width direction. When tension is applied to a part of the sheet in rolling in the width direction, as shown in Figure 7, the same effect is obtained as in the case where the defor-mation resistance of that part of the sheet in rolling where the tension is applied decreases, and the draft of this part increases. In the current cold tandem mills for sheets, tension is usually applied to the sheet in rolling before and after stands. Therefore, an irregular flatness of the sheet in rolling in the preceding stands of a mill is spontaneously corrected to some extent by a difference in tension in the sheet in rolling spontaneously occurring in the width direction.
As a result of studies with consideration to the above-mentioned known facts, it has been demonstrated that a finished sheet with defective flatness can be satisfactorily corrected during rolling if said sheet in rolling is positively subjected to a tension which will promote the differ-ence in tension spontaneously generated in response to the uneven flatness _ g _ of said sheet in rolling.
In accordance with aspects of this invention, application of a tension which will promote the above-menti~ned difference in tension spont2neously generated in response to the defectlve flatness of the sheet in rolling is accomplished by giving a vertical displacement tc said sheet in rolling ln the width d'rection.
As seen in Figure 8, which is a schematic perspective view of apparatus for carrying out the method of one aspect of this inverltion, a sheet S is rolled by rolliDg through work rolls 1 and back-up rolls 2.
A flatness control~er is pro~ded belcw the sheet S, upstream of the rolls 1 and 2. Moreover, an auxiliary roller 5 is shown prc,vided above the sheet S, also uFstream of the rolls 1 and 2.
In a case where wavy edge (see Figure 3(a) to (d)) occurs during rolllng, vertical dlsplacemcnt i8 given, as is sh~ln in the perspective vi~w in Figure 8, to the central area C of the sheet S in rolling th~ough work rol3s 1 and back-up rolls 2 by raising the part of a fl~tness control-ler 4 ~hich cc~mprises several rollers with a barrel len~t~- shorter than the width of sheet S in rolling. The part of the flats~ess controller 4 corre&ponds to the central area C o' sheet S in rolling in the width direction, thereby increasin~ the tension in the central area C of sheet S
in rolling. Figure 9 is 2 front view which illustrates an outline of the case where vertical displzcement is given to the central area C of the sheet S in rollln~ accordi~g to the enbodiment shown in Figure 8.
As mentioned hereirabove, in Figure 8, S designates an auxiliary roller for provid ng a sufficient tension of as- appropriate amou~t of disp~ace~lent ~hen a vertical displacement i& given to sheet S in rolling by means of flatness controller 4. Auxiliary roller 5 need not be a flat roller and may be a roller of various crowns. Auxiliary roller 5 may not be used when the poin~ of sheet S in rollir.g where displacement ic given is sufficiently close tG rolls 1 and 2.
When center buckling (see Figure l(a) to (d)) occurs during rolling, a vertical d-.splacement is given to the lateral edges of the sheet S in rolling by rcising the part of f~atness controller 4 corresponding to the - lC -~038662 lateral edges E oi sheet S in rol~ing, thereby increasing the tension inthe lateral edges E of sheet S in rolling.
This inve~tion, in one of its embodiments, is described in more detail with reference to Figure 10. As is sho~n ln Figure 10, the flat-ness contrcllers 4 for providing displacement to t~!e sheet S in rolling are arIanged be ore ~nd after work rolls 1, i.e., both upstream and down-stream of ~ork rolls 1. (For the sake of clarity, back-up rolls have been omitted fro~ Figur~. 10). The auxiliary roller 5 is provided on the left s~de in the drawing of said flatness cortroller 4, (l.er, upstream of flatness controller '~, and another auxiliary roller 5, and a flatness detector 6 are provided ad~acent to each other on the right side in the drawing of saic flatnesF controller 4, (i.e., d~wnstream of flatness controller 4). Flatness detector 6 is connected to flatrless contro~ler L through ~ signa converter 7 and a control~er 8. Therefore, when wavy edge occurs in the sheet S during rolling, flatness detector 6 detects this defectlve flatn~ss and the detection result is converted into a sign~l in signal cos-verter 7. On recei~ing this signal, controller 8 operates to raise only the ~art of flatr.ess controller 6 com)ected to controller 8, correspondin~ to the central area C of sheet S in rol~ing in the width direction, in the vertical directicn of sheet S in rolling. As a result, since a vertical displacenent is given to sheet S in rolling in the central area C in the width d rection, a tension distribution in the width direc~
tion having t~,e maximun value in ~he middle of the width is added to the tensian of sheet S in rolling, thereby correeting the wavy edge of sheet S in rolllng.
Althou~h there are variouo methods of adding the above--mentioned tension distribution, it has been fcund that the above-mentioned method usin~ the ilatress controller is best suited according to a preferred aspecL of this inven~ion ~or controlli~g the flaLness of a ~heet dur$ng rGlling.
Tke re2son is explai~ed below.
Figure ll(a) shows a perspective vie~ o the state of displacement of a cold rolled steel skeet ~aving a thickr.ess of C.Smm and a width of ~03~6Z
900~n, with th~ left end fixed and tbe riht end fixed at a point 1,000 mm away from the fixed left end, when this steel sheet $s sub~ected to a con-centrated load of 40 kg at a point in the middle 500m~ away from the left iixed end. As shown in Figure ]l(b~, a vertical displflcement occurs along the cen1:er line due to this loading and amounts to 13 mm at the 'oading point. As a result, a tens'on distr~bution as shown in ~igure ll(c) is generated in the sheet. Since such tension distribution is symmetrical, o~ly t~le tension distribution in a half of the sheet is shown in Figure ll(c). As is apparent from this drawing, the difference in tens'on in the width direction between the sheet center and the sheet end decre~ses with increasing distance from the loading poinL and with decreasing dis-tance from ~e fixed point. For example, although the d'fference in tension in the width direction is 13 kg/mm at a point 450 mm away from the fixed point, it becomes 2.5 kglmm at a point 50 mm away from the fixed point. In Figure 11, the fixed point simulates the rolling mill rolls 1 and 2 i~ Figure 10, and the 'oading point, the flatness controller 4 in Figure 10.
Figure ]2(a) shous the tension distribution in the sheet in rolling in the ~Jidth directicn on ~he roll entry ide obtained in this manner, and ~igure 12~b) shows the thickness distribution of the finished sheet in the case where such tens~on distribution is given to the sheet in rolling. In ~igure 12(b), the sclid line represents the thickness di~-tribution of the sheet rolled under tens'on uniform in the width direction, and the broken i~ne represents ahe t~)ickness distribution of the sheet rolled under the tension distribution shown in Figure ~2(a). As is apparent ~rom this figure, the ~iifference in thickness of the fi~ished sheet in the width direction under a uniform tensicn is O.Q55 mm and the difference in thickness of the finisked sheet in the width direction under the tension distribution shown in Figure 12(a) is 0.045 mm. Therefore, the d'fference bet~een these t~70 values is 10~ and amounts to 2% in terms of deviation from the medium thickness. The method of an aspect of th-'s in~ention permits sufficient control of the flatness of ~ sheet in rolling, because the thicknes~ deviation of heet with defective flatness produced in the current rolling mills is 1.0~ at the maximum.
Accorting to the studies made by the inventors, it is necessary to give a vertical displacement of st ~east 5 mm to a sheet in rolling under a maximum load of 1,000 kg u~ing the flatness controller, for effec-tively controlling the flatness of the sheet in rolliDg according to tke ethod of aspects of this invention. With the present state of the art, it iB quite easy to design and manufacture flatneRs controllers having such czpaclty as described above. The method of aspects of this nvention i8 simple and highly practical for controlling the flat~ess of a sheet in rolling.
As amplified above, the method of aspects of tkis invention permits correcting vsrious defects i~ flatness of the sheet in rolling in a short response time and great~y contributes to the improvement in quality of the f~nished sheet. Moreover, the metkod of aspects of thls invention is appllcable also for hot rolling, leveller, s~in pass rolling, etc. iD addition to cold rolling, thus producing industrially useful effect.
These conventional methods and disadvantages thereof are described below.
(1) Roll bending method:
This is a method for correcting a sheet defective in flatness in rolling over the entire width which comprises, providing roll neck ends of work rolls and back-up rolls with pressure applying devices such as, for example, hydraulic cylinders and giving forced bending to the work rolls and/or the back-up rolls thereby cha~ging the roll profiles. However, as the diameter of the rolls becomes larger, it becomes more difficult to bend the work rolls and the back-up rolls and considerably large pressure applying devices (bending devices) are required, especially for the back-up rolls which have a larger roll diameter. In addition, when only the work rolls are bent, the bending effect is limited to the ends of the sheet in rolling. Therefore, in this case, this method is not effective in preclud-ing the occurrence of center buckling.
(2) Asymmetrical roll bending method:
This is a method for correcting a sheet defective in flatness in rolling over the entire width which comprises applying an asymmetrical rolling force to the sheet in rolling in the width direction (see, for example, Japanese Patent Provisional Publication No. 10,855/74). More specifically, pressures are applied to neck ends of the work rolls in a certain stand, locally to correct the defective flatness of the sheet in rolling. Then, pressures are applied to the left-hand roll neck ends of the work rolls in the following stand, to correct the defective flatness of the other part of said sheet in rolling, whereby the flatness of said sheet in rolling is controlled over the entire width. In this method, rolling forces applied asymmetrically in the width direction to the sheet in rolling, pose a problem in the stability of threading between stands.
(3) Thermal crown control method: ¦
The unbalance between the heat input from the sheet in rolling to ~-~
~,~
the rolling mill rolls and the heat output from the rolls caused by radiation gives rise to unbalanced temperature distribution within the rolls, as a result of which urlbalanced thermal expansion occurs in the rolls, thus changing the profileQ of the rolls. (This phenomenon is called thermal crown.) The thermal crown control method for correcting a sheet defective in flatness in rolling over the entire width comprises, spraying lubricating oil over the work rolls and back-up rolls from lub- r ricating oil sprays and changing the capacity of the lubricating oil for cooling the work rolls and the back-up rolls in the axial direction of the rolls (i.e., in the width direction of the sheet in rolling) by regulating the amount of spray of the lubricating oil, thereby controlling the dis- _ tribution of the amount of the above-mentioned tbermal crown in the axial direction of the rolls (see, for example, Japanese Patent Publication No.
49-9031, March 1, 1974. In this method, since the temperature of lubricating oil is relatively high, the cooling capacity of lubricating oil is limited to a certain range. Moreover, changes in thermal crown are not always proportional to changes in the cooling capacity of lubricating oil. In addition, as it takes time for changes in thermal crown to respond to .
changes in the cooling capacity of lubricating oil, it is not feasible L
to control the flatness of the sheet in rolling in a short time.
(4) Flatness control method using rolling oil:
This is a method for correcting a sheet defective in flatness in rolling over the entire width which comprises increasing or decreasing in 3~ the width direction the friction between the rolling mill rolls and the sheet in rolling by increasing or decreasing the amount of rolling oil in the width direction, thereby changing the distribution of rolling force in the width direction (see, for example, Japanese Patent Provisional Pub-B -~-`" 103~662 lication Nos. 23.157/74 and 28,555/74). Although this method is effec-tive in hot rolling, it does not seem to be as effective in cold rolling.
As mentioned above, although several methods have been proposed for precluding the occurrence of finished sheets with defective flatness by controlling the flatness of the sheet during rolling, satisfactorily effective methods have not as yet been developed.
Therefore, an object of one aspect of this invention is to provide, in rolling a metal sheet through rolling mill rolls, a method of greatly minimizing or even precluding the occurrence of finished metal sheet with defective flatness by controlling the flatness of the sheet during rolling.
An object of a principal aspect of this invention is to provide a simple and practical method of greatly minimizing or even precluding the occurrence of finished metal sheet with defective flatness by giving a desired change to the tension distribution in the sheet in rolling inthe width direction, thereby controlling the flatness of the sheet during rolling.
By one broad aspect of this invelltion, a method is provided for controlling the flatness of a metal sheet during rolling of the sheet through rolling mill rolls, which comprises the steps of:
arranging a plurality of flatness controlling rollers, each with a barrel length shorter than the width of said sheet, downstream of said rolling mill rolls, in a fashion adjacent one another with their axial direction substantially perpendicular to the direction of rolling of the sheet to extend transversely across the width of thc sheet, said pluralitv of flatncss controlling rollers being selectively individllal]y vertically movable; and changing the tension distribntion in said sheet during rolling tllereof in the width direction by moving at least one of said plurality of rollers relative to said sheet to give a vertical displace-ment to the corresponding part of said sheet during rolling, thereby increasing the draft in said par-t of said sheet during rolling.
By one variant, the.metnod includes the step of arranging an auxiliary undriven roller downstream of said rolling mill rolls and at a location more distant from said rolling mill rolls than said plurality of flatness controlling rollers, thereby aiding said flatness controlling rollers to change the tension distribution in said sheet effectively.
By a preferred variant, the flatness controlling rollers are located below said sheet and are selectively raised to change said tension distribution in said sheet during rolling.
By yet another variant, the vertical displacement given to said metal sheet during rolling by said flatness controlling rollers~ is at least 5mm.
Of the accompanying drawings:
-4a-~03~62 Figures l(a), l(b), l(c), l(d), 2(a), 2(b), 2(c), 2(d), 3(a), 3(b), 3(c) and 3(d) are schematic drawings of a finished sheet with defective flatness, wherein figures (a) are perspective views of a finished sheet with defective flatness, figures (b) are the sectional views of the finished sheet in the width direction, figures (c) are graphs which show the tension distribution in the finished sheet in the width direction, and figures (d) are graphs which show the thickness distribution of the finished sheet in the width direction;
Figures 4 to 6 are schematic drawings which illustrate some con-ventional methods of precluding the occurrence of finished sheet with defective flatness;
Figure 7 is a schematic drawing which illustrates the effect oftension on rolling force;
Figures 8 to 10 are schematic drawings which give an outline of the method of embodiments of an aspect of this invention;
Figure ll(a) is a perspective view which illustrates the state of displacement of a sheet; Figure ll(b) is a graph which illustrates the amount of vertical displacement of the sheet in the width direction (i.e., the rise of the sheet); and Figure ll(c) is a graph which illustrates the tension distribution generated in the sheet during the displacement;
and Figure 12(a) shows a curve which represents the relation between the distance in the width direction and the tension distri~ution in a sheet; and Figure 12(b) gives a curve which indicates the relation between the distance in the width direction and the thickness distribution of said sheet.
As mentioned above, Figures 1 to 3 show the relation between the thickness distribution in the width direction after rolling in the case of a uniform thickness at the roll entry and the state of defective flat-ness of the finished sheet, resulting from the thickness distribution.
The state of defective flatness as shown in Figure 1 is called center buc~ling; the state of defective flatness as shown in Figure 2 is celled quarter buckling; and the state of defective flatness as shown in Figure 3 is called wavy edge. 103~6Z
Referring to Figures l(a) - (d), it is seen that the sheet S
has defective flatness i.e., center buckling. As shown in Figure l(b) the cross-section of the sheet S is of double concave appearance. As shown in Figure l(c) the tension distribution across the width of the sheet varies from stretching tension at the edges E of the sheet, to compression tension in the central areas C of the sheet. Similarly, as shown in Figure l(d), the thic~ness distribution across the width of the sheet varies from thick areas at the edges E of the sheet, to thinner areas in the central areas C of the sheet.
Referring to Figures 2(a) - (d), it is seen that the sheet S has defective flatness i.e., quarter buckling. As shown in Figure 2(b) the cross-section of the sheet S is of wavy appearance, i.e., it includes a thick region at the transverse line of symmetry and both right side and left side double concave shapes. As shown in Figure 2(c) the tension distribution across the width of the sheet varie8 in the form of a sine wave, i.e., it has stretching tension at the edges E and at the transverse line of symmetry L, and compression tension in the central areas between the edges E and the line of symmetry L. Similary, as shown in Figure 2(d), the thickness distribution across the width of the sheet varies in the form of a since wave, with thick areas at the edges E and at the line of symmetry L, and thinner areas C between the thick portions.
Referring to Figures 3(a) - (d), it is seen that the sheet S has defective flatness, i.e., wavy edge. As shown in Figures 3(b), the cross-section of the sheet S is of double convex appearance. As shown in Figure 3(c) the tension distribution across the width of the sheet varies from compression tension at the edges E, to stretching tension at central areas C. Similarly, as shown in Figure 3(d), the thickness distribution across the width of the sheet varies from thin areas at the edges E to thicker areas at the central areas C.
As shown in Figure 4 providing the roll neck ends 1 and 2 of work rolls 1 and back-up rolls 2 with pressure applying devices, such as, for example, hydraulic cylinders H and giving forced bending to work rolls 1 ~038662 and/or back-up rolls 2, thereby changing the roll profiles. However, as the sixe of the diameter of work rolls 1 and back-up rolls 2 becomes larger, it becomes difficult to bend work rolls 1 and back-up rolls 2 and considerably large pressure applying devices (bending devices) H are required especially for back-up rolls 2 which have a larger roll diameter.
In addition, when only the work rolls 1 are bent, the bending effect is limited to the ends of the sheet S in rolling.
As shown in Figure 5(a), pressures are applied as indicated by the arrows A to the roll neck ends at the right hand side of work rolls 1 in a certain stand, locally to correct the defective flatness of the sheet S
in rolling. Then, as shown in Figure 5(b), pressures are applied as indicated by the arrows A to the roll neck e~ds 1 at the left hand side of work rolls 1 in the following sLand, to correct the defective flatness of the other part of sheet S in rolling, whereby the flatness of sheet S
in rolling is controlled over the entire width.
As shown in the side elevation and plan view in Figures 6(a) and (b), respectively, lubricating oil is sprayed over work rolls 1 and back-up rolls 2 from lubricating oil sprays through nozzles 3. The capacity of the lubricating oil for cooling said work rolls 1 and back-up rolls 2 in the axial direction thereof, (i.e., in the width direction of the sheet S in rolling) is changed by regulating the amount of spray of lubricating oil, through nozzles 3 thereby controlling the distribution of the amount of the thermal crown in the axial direction of the rolls 1 and 2.
As is well known, according to Dr. D.R. Bland and Dr. H. Ford, the following equations stand with regard to the rolling of a metal sheet through rolling mill rolls:
P = R' r ~P d~ + R'J O P d~
P = km~l -qf/km)h/h2e f~
p km(l qb/ m) / 1 Where, P : Rolling load, P : Rolling pressure acting on the part from the neutral point ~03866Z
~- to the roll bite exit. (The neutral point is defined as the point where the roll peripheral speed corresponds to the forward speed of the sheet in rolling. The ro'l bite is the contact surface between the rolls and the sheet in rolling.), P : Rolling pressure acting on the part rom the neutral point to the roll bite entry, k : Mean dcformation resistance of the sheet in rolling, m qf : Front ~ension applied to the sheet in rolling (i.e., tension on the roll exit s~de), qb : Back tension applied to the sheet in rolling (i.e., tension on the roll entry side), h : Thickness of the sheet in rolling at an arbitrary point within the roll bite, hl : T~ic~ness of the sheet in rolling at the roll entry, h2 : Thickness of the sheet in rolling at the roll exit, O : Roll center angle comprising the part of the roll bite between bite exit and the position corresponding t to thickness h, t ~ : Roll center angle comprising the part of the roll bite between the neutral point and the bite exit, : Roll center angle comprising the part of the roll bite between the bite entry and the bite exit, R' : Flattened radius of roll, : Coefficient of friction between the sheet in rolling and the rolls, H : 2 ~ tan ~ 0 , and ~11 : H at the roll bite entry.
Further, Dr. A.J.F. ~lacQueen has experimentally confirmed the 3() validity of the following equations holding between the factors:
T 0.16 TF + 0.32 TB
Where, P : Rolling load, P : Rolling load required when no tension is applied to the sheet in rolling, PT : Amount of decrease in rolling load when tension is applied to the sheet in rolling, TF : Front tension applied to the sheet in rolling (i.e., tension on the roll exit side), and TB : Back tension applied to the sheet in rolling (i.e., tension on the roll entry side).
As is apparent from the above-mentioned equations, when tension i8 applied to the sheet in rolling, the same effect is obtained as in the cS~se where the deformation resistance of said sheet in rolling decreases, and accordingly, the rolling force on the rolling mill rolls decreases.
When the rolling force on the rolling mill rolls decreases, the thickness of the sheet in rolling is reducet by the elastic teformation of the rolling mill if the mill setting is kept unchanget. It is ascertained that these relations can be appliet for gage control of finishet sheets such as, for example, thin steel sheets.
The foregDing i8 applicable in a case where the tension applied to the sheet in rolling varies in the width direction. When tension is applied to a part of the sheet in rolling in the width direction, as shown in Figure 7, the same effect is obtained as in the case where the defor-mation resistance of that part of the sheet in rolling where the tension is applied decreases, and the draft of this part increases. In the current cold tandem mills for sheets, tension is usually applied to the sheet in rolling before and after stands. Therefore, an irregular flatness of the sheet in rolling in the preceding stands of a mill is spontaneously corrected to some extent by a difference in tension in the sheet in rolling spontaneously occurring in the width direction.
As a result of studies with consideration to the above-mentioned known facts, it has been demonstrated that a finished sheet with defective flatness can be satisfactorily corrected during rolling if said sheet in rolling is positively subjected to a tension which will promote the differ-ence in tension spontaneously generated in response to the uneven flatness _ g _ of said sheet in rolling.
In accordance with aspects of this invention, application of a tension which will promote the above-menti~ned difference in tension spont2neously generated in response to the defectlve flatness of the sheet in rolling is accomplished by giving a vertical displacement tc said sheet in rolling ln the width d'rection.
As seen in Figure 8, which is a schematic perspective view of apparatus for carrying out the method of one aspect of this inverltion, a sheet S is rolled by rolliDg through work rolls 1 and back-up rolls 2.
A flatness control~er is pro~ded belcw the sheet S, upstream of the rolls 1 and 2. Moreover, an auxiliary roller 5 is shown prc,vided above the sheet S, also uFstream of the rolls 1 and 2.
In a case where wavy edge (see Figure 3(a) to (d)) occurs during rolllng, vertical dlsplacemcnt i8 given, as is sh~ln in the perspective vi~w in Figure 8, to the central area C of the sheet S in rolling th~ough work rol3s 1 and back-up rolls 2 by raising the part of a fl~tness control-ler 4 ~hich cc~mprises several rollers with a barrel len~t~- shorter than the width of sheet S in rolling. The part of the flats~ess controller 4 corre&ponds to the central area C o' sheet S in rolling in the width direction, thereby increasin~ the tension in the central area C of sheet S
in rolling. Figure 9 is 2 front view which illustrates an outline of the case where vertical displzcement is given to the central area C of the sheet S in rollln~ accordi~g to the enbodiment shown in Figure 8.
As mentioned hereirabove, in Figure 8, S designates an auxiliary roller for provid ng a sufficient tension of as- appropriate amou~t of disp~ace~lent ~hen a vertical displacement i& given to sheet S in rolling by means of flatness controller 4. Auxiliary roller 5 need not be a flat roller and may be a roller of various crowns. Auxiliary roller 5 may not be used when the poin~ of sheet S in rollir.g where displacement ic given is sufficiently close tG rolls 1 and 2.
When center buckling (see Figure l(a) to (d)) occurs during rolling, a vertical d-.splacement is given to the lateral edges of the sheet S in rolling by rcising the part of f~atness controller 4 corresponding to the - lC -~038662 lateral edges E oi sheet S in rol~ing, thereby increasing the tension inthe lateral edges E of sheet S in rolling.
This inve~tion, in one of its embodiments, is described in more detail with reference to Figure 10. As is sho~n ln Figure 10, the flat-ness contrcllers 4 for providing displacement to t~!e sheet S in rolling are arIanged be ore ~nd after work rolls 1, i.e., both upstream and down-stream of ~ork rolls 1. (For the sake of clarity, back-up rolls have been omitted fro~ Figur~. 10). The auxiliary roller 5 is provided on the left s~de in the drawing of said flatness cortroller 4, (l.er, upstream of flatness controller '~, and another auxiliary roller 5, and a flatness detector 6 are provided ad~acent to each other on the right side in the drawing of saic flatnesF controller 4, (i.e., d~wnstream of flatness controller 4). Flatness detector 6 is connected to flatrless contro~ler L through ~ signa converter 7 and a control~er 8. Therefore, when wavy edge occurs in the sheet S during rolling, flatness detector 6 detects this defectlve flatn~ss and the detection result is converted into a sign~l in signal cos-verter 7. On recei~ing this signal, controller 8 operates to raise only the ~art of flatr.ess controller 6 com)ected to controller 8, correspondin~ to the central area C of sheet S in rol~ing in the width direction, in the vertical directicn of sheet S in rolling. As a result, since a vertical displacenent is given to sheet S in rolling in the central area C in the width d rection, a tension distribution in the width direc~
tion having t~,e maximun value in ~he middle of the width is added to the tensian of sheet S in rolling, thereby correeting the wavy edge of sheet S in rolllng.
Althou~h there are variouo methods of adding the above--mentioned tension distribution, it has been fcund that the above-mentioned method usin~ the ilatress controller is best suited according to a preferred aspecL of this inven~ion ~or controlli~g the flaLness of a ~heet dur$ng rGlling.
Tke re2son is explai~ed below.
Figure ll(a) shows a perspective vie~ o the state of displacement of a cold rolled steel skeet ~aving a thickr.ess of C.Smm and a width of ~03~6Z
900~n, with th~ left end fixed and tbe riht end fixed at a point 1,000 mm away from the fixed left end, when this steel sheet $s sub~ected to a con-centrated load of 40 kg at a point in the middle 500m~ away from the left iixed end. As shown in Figure ]l(b~, a vertical displflcement occurs along the cen1:er line due to this loading and amounts to 13 mm at the 'oading point. As a result, a tens'on distr~bution as shown in ~igure ll(c) is generated in the sheet. Since such tension distribution is symmetrical, o~ly t~le tension distribution in a half of the sheet is shown in Figure ll(c). As is apparent from this drawing, the difference in tens'on in the width direction between the sheet center and the sheet end decre~ses with increasing distance from the loading poinL and with decreasing dis-tance from ~e fixed point. For example, although the d'fference in tension in the width direction is 13 kg/mm at a point 450 mm away from the fixed point, it becomes 2.5 kglmm at a point 50 mm away from the fixed point. In Figure 11, the fixed point simulates the rolling mill rolls 1 and 2 i~ Figure 10, and the 'oading point, the flatness controller 4 in Figure 10.
Figure ]2(a) shous the tension distribution in the sheet in rolling in the ~Jidth directicn on ~he roll entry ide obtained in this manner, and ~igure 12~b) shows the thickness distribution of the finished sheet in the case where such tens~on distribution is given to the sheet in rolling. In ~igure 12(b), the sclid line represents the thickness di~-tribution of the sheet rolled under tens'on uniform in the width direction, and the broken i~ne represents ahe t~)ickness distribution of the sheet rolled under the tension distribution shown in Figure ~2(a). As is apparent ~rom this figure, the ~iifference in thickness of the fi~ished sheet in the width direction under a uniform tensicn is O.Q55 mm and the difference in thickness of the finisked sheet in the width direction under the tension distribution shown in Figure 12(a) is 0.045 mm. Therefore, the d'fference bet~een these t~70 values is 10~ and amounts to 2% in terms of deviation from the medium thickness. The method of an aspect of th-'s in~ention permits sufficient control of the flatness of ~ sheet in rolling, because the thicknes~ deviation of heet with defective flatness produced in the current rolling mills is 1.0~ at the maximum.
Accorting to the studies made by the inventors, it is necessary to give a vertical displacement of st ~east 5 mm to a sheet in rolling under a maximum load of 1,000 kg u~ing the flatness controller, for effec-tively controlling the flatness of the sheet in rolliDg according to tke ethod of aspects of this invention. With the present state of the art, it iB quite easy to design and manufacture flatneRs controllers having such czpaclty as described above. The method of aspects of this nvention i8 simple and highly practical for controlling the flat~ess of a sheet in rolling.
As amplified above, the method of aspects of tkis invention permits correcting vsrious defects i~ flatness of the sheet in rolling in a short response time and great~y contributes to the improvement in quality of the f~nished sheet. Moreover, the metkod of aspects of thls invention is appllcable also for hot rolling, leveller, s~in pass rolling, etc. iD addition to cold rolling, thus producing industrially useful effect.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for controlling the flatness of a metal sheet during rolling of the sheet through rolling mill rolls, which comprises the steps of:
arranging a plurality of flatness controlling rollers, each with a barrel length shorter than the width of said sheet, downstream of said rolling mill rolls, in a fashion adjacent one another with their axial direction substantially perpendicular to the direction of rolling of the sheet to extend transversely across the width of the sheet, said plurality of flatness controlling rollers being selectively individually vertically movable; and changing the tension distribution in said sheet during rolling thereof in the width direction by moving at least one of said plurality of rollers relative to said sheet to give a vertical displacement to the corresponding part of said sheet during rolling, thereby increasing the draft in said part of said sheet during rolling.
arranging a plurality of flatness controlling rollers, each with a barrel length shorter than the width of said sheet, downstream of said rolling mill rolls, in a fashion adjacent one another with their axial direction substantially perpendicular to the direction of rolling of the sheet to extend transversely across the width of the sheet, said plurality of flatness controlling rollers being selectively individually vertically movable; and changing the tension distribution in said sheet during rolling thereof in the width direction by moving at least one of said plurality of rollers relative to said sheet to give a vertical displacement to the corresponding part of said sheet during rolling, thereby increasing the draft in said part of said sheet during rolling.
2. The method of claim 1 including the step of arranging an auxiliary undriven roller downstream of said rolling mill rolls and at a location more distant from said rolling mill rolls than said plurality of flatness controlling rollers, thereby aiding said flatness controlling rollers to change the tension distribution in said sheet effectively.
3. The method of claim 1 wherein said flatness controlling rollers are located below said sheet and are selectively raised to change said tension distribution in said sheet during rolling.
4. The method as claimed in claims 1, 2 or 3, wherein said vertical displacement given to said metal sheet during rolling by said flatness controlling rollers is at least 5mm.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP49089438A JPS5118252A (en) | 1974-08-06 | 1974-08-06 | Atsuenkinzokubanno choryokubunpunyoru keijoseigyoho |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1038662A true CA1038662A (en) | 1978-09-19 |
Family
ID=13970669
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA232,697A Expired CA1038662A (en) | 1974-08-06 | 1975-08-01 | Method for controlling flatness of metal sheet in rolling |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5118252A (en) |
| CA (1) | CA1038662A (en) |
| DE (1) | DE2532743A1 (en) |
| FR (1) | FR2281178A1 (en) |
| GB (1) | GB1496946A (en) |
| IT (1) | IT1039246B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5458731A (en) * | 1977-10-19 | 1979-05-11 | Mitsubishi Electric Corp | Coating for electrodeposition |
| FR2464106A1 (en) * | 1979-08-30 | 1981-03-06 | Chabanov Alim | Automatic control of cross=section profile of rolled strip - via electronic circuit which accurately adjusts tension across strip leaving hot or cold rolling mill |
| EP0028275B1 (en) * | 1979-11-01 | 1984-04-04 | Reycan Research Limited | Apparatus for controlling the shape of aluminium sheet produced in a rolling mill |
| JPS5680904U (en) * | 1979-11-28 | 1981-06-30 | ||
| JPS60231109A (en) * | 1984-05-01 | 1985-11-16 | Kanzaki Paper Mfg Co Ltd | System for recording and displaying measured quality data of wound-up strip like material |
| DE3435232A1 (en) * | 1984-09-26 | 1986-04-17 | Hoesch Stahl AG, 4600 Dortmund | METHOD AND DEVICE FOR CORRECTING THE THICKNESS PROFILE OF THE STRIP TO BE ROLLED ON A MULTIPLE-STANDARD HOT-ROLLING ROLL MILL |
| JPH0671610B2 (en) * | 1985-11-15 | 1994-09-14 | 株式会社日立製作所 | Shape control method and apparatus for strip rolling |
| IT1292458B1 (en) * | 1997-07-02 | 1999-02-08 | Demag Italimpianti Spa | METHOD OF ROLLING A METAL TAPE AND ROLLING MILL FOR IMPLEMENTING THE METHOD |
| DE19919801A1 (en) * | 1999-04-30 | 2000-11-02 | Josef Froehling Gmbh Walzwerks | Strip tension distribution is measured during rolling by measuring strip flatness |
| JP4410835B2 (en) * | 2008-03-28 | 2010-02-03 | 株式会社神戸製鋼所 | Aluminum alloy thick plate and manufacturing method thereof |
-
1974
- 1974-08-06 JP JP49089438A patent/JPS5118252A/en active Granted
-
1975
- 1975-07-08 GB GB2865375A patent/GB1496946A/en not_active Expired
- 1975-07-11 IT IT2535875A patent/IT1039246B/en active
- 1975-07-22 DE DE19752532743 patent/DE2532743A1/en not_active Ceased
- 1975-08-01 CA CA232,697A patent/CA1038662A/en not_active Expired
- 1975-08-06 FR FR7524549A patent/FR2281178A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5532442B2 (en) | 1980-08-25 |
| FR2281178A1 (en) | 1976-03-05 |
| JPS5118252A (en) | 1976-02-13 |
| GB1496946A (en) | 1978-01-05 |
| IT1039246B (en) | 1979-12-10 |
| DE2532743A1 (en) | 1976-02-26 |
| FR2281178B1 (en) | 1979-02-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2098309B1 (en) | Method of temper rolling of steel strip and process for manufacturing high tensile cold rolled steel sheet | |
| CA1038662A (en) | Method for controlling flatness of metal sheet in rolling | |
| CN109332387B (en) | Temper mill for preventing middle wave shape, production system and production method | |
| US4528830A (en) | Method for changing widthwise distribution of thickness of metal strip | |
| US4856313A (en) | Method of controlling strip crown in planetary rolling | |
| JPH0521653B2 (en) | ||
| JPS6210722B2 (en) | ||
| JP2019141874A (en) | Cold rolling method of metal strip | |
| JPS59113904A (en) | Cold tandem rolling train | |
| JPS6141643B2 (en) | ||
| RU2776314C1 (en) | Rail rolling method (variants) | |
| EP1188493B1 (en) | Control method for rolling a strip in a rolling stand | |
| JPH0669569B2 (en) | Manufacturing method of extra thick steel plate with excellent internal properties | |
| RU2170150C1 (en) | Method for rolling round cross section shapes | |
| AU681219B2 (en) | H-steel manufacturing method | |
| US3850020A (en) | Rolled strip shape control using work roll screwdown changes | |
| US6408665B1 (en) | Finish hot rolling method for structural steels | |
| RU2164186C2 (en) | Method for profiling equal-flange channel bars | |
| JP6747256B2 (en) | Method for manufacturing H-section steel | |
| CA1302743C (en) | Method of controlling strip crown in planetary rolling | |
| SU865440A1 (en) | Steel hot-rolling method | |
| SU971575A2 (en) | Method for making wire from sintered tungsten-based materials | |
| JP6703306B2 (en) | Method for manufacturing H-section steel | |
| SU899170A1 (en) | Strip rolling method | |
| RU2187391C1 (en) | Billet rolling method |