FR2628987A1 - Metal sheet cold rolling mill - has tension system with staggered rows of rollers on either side of stand - Google Patents

Abstract

A cold-rolling mill, designed to produce thin and extra-thin sheet metals, consists of an uncoiling roller (2), a multi-cylinder roller stand (3,6,7) and a coiling roller (10). It is also equipped with a tensioning system (20,40) for the metal sheet, situated in between the uncoiling and coiling rollers (2,10) and independent of the two. The tensioning system is made up of a number of rollers (21,41) with adjustable speed to allow the desired traction to be achieved. The tensioning rollers (21,41) are set in staggered rows and are located on either side of the rolling stand to provide independent tension for the sheet metal before it enters and after is leaves the rolling stand. The number of tensioning rollers in each section is selected so as to achieve the required friction coefficient between the rollers and the sheet metal, and in each section there are at least two rollers. ADVANTAGE - Suitable for producing metal sheet from 1.0 mm thick down to 0.1 mm thick. (14pp Dwg.No.2/2)

Description

FRENCH REPUBLIC NOR publication: 2 628 987 (use only for

  the NATIONAL INSTITUTE reproduction orders)

INDUSTRIAL PROPERTY

  OF INDUSTRIAL PROPERTY National registration number 88 03987 PARIS

) Int Cl ': B 21 B 39/08, 41/00.

@ A1 PATENT APPLICATION

  Filing date March 25, 1988. (Applicant (s): Company known as: UGINE, Aciers de Chatil-

Ion and Gueugnon. - FR.

Q Priority:

    Inventor (s) Jacques Nesme: Gérard Vialleton.

  Date of public availability of the

  BOPI application "Patents" n 39 of September 29, 1989.

  (References to other national documents appearing

rentés: rn Holder (s)

(Agent (s) Cabinet Lavoix.

  (Device for cold rolling thin and extra-thin sheets.

  (The present invention relates to a laminating device

  cold swimming for the production of thin and extra thin sheets

  thin, comprising a winder-unwinder 2, at least one cage 5 of conventional multi-cylinder rolling 6, 7, and a winder winder. 2 "t The device also comprises tensioning means 20, M: of the strip 1 located between the winders 2, 10 and independent of the latter, said tensioning means 20, l (4 q = 40 being made up of a any number of rollers 21, 1k L, 43 _ b 41, the respective speeds of which are adjustable in order to obtain u

  set the desired rolling tension.

  N DV (o IL. D Sale of booklets at IMPRIMERIE NATIONALE, 27. rue de la Convention - 75732 PARIS CEDEX 15 The present invention relates to a device for cold rolling thin and extra-thin sheets,

of all usual widths.

  Rolling mill trains specializing in the manufacture of thin sheets and strips less than 1 mm thick, and extra-thin sheets, i.e.

  less than 0.1 mm thick, are generally made up of

  killed either from a quarto cage with two large cy-

  support linders and two small work cylinders

  vail, or a multi-cylinder cage supporting two

  small working cylinders, such as a Senzi- cage

  mir for example, the product in reels coming from an unwinding reel and being, after the pass of

  rolling, on a winder-winder.

  The product can also, between the winder-

  unwinder and winder-winder, continuously undergo rolling by two or more successive tandem stands.

  In cold rolling, the difficulties become

  grow with the small thickness desired, and also with certain grades of steel, such as stainless steels rolled in thicknesses less than

0.1 mm.

  At these degrees of difficulty appear

  sometimes insurmountable contradictions between impe-

  technical constraints and economic imperatives. Thus, for example, by rolling stainless steel strips with a thickness of less than 0.1 mm, in order to satisfy economic requirements, it is necessary to achieve total hardening percentages of at least 50'Z between two anneals, the sheet or strip reaching a very high elastic limit. For this, high rolling pressures and

  very strong pulls on the strip, necessary conditions

  to finally achieve perfect flatness

of the laminated strip.

  In the smallest thicknesses and for the strongest work hardenings, the rolling traction to be applied to the strip can reach

Kg / mm2.

  Generally, the rolling traction on the strip is exerted by the winder, more exactly

by its winding mandrel.

  However, experience shows that, for example, for a sheet or strip with a thickness less than 0.1 mm and a width greater than 500 mm, a winding traction greater than 15 Kg / mm2 causes the appearance on the strip of "nerves" which form between the deflector rollers (adjusting without traction

  the orientation of the strip) and the winding mandrel-

  which leads to the formation of folds in the strip,

  There is then an incompatibility between the trac-

  high tion, associated with high rolling pressures

  and dictated by economic imperatives of producti-

  speed, and the technical need for low traction

for winding.

  In addition, the pulls to be applied on the winder-winder for rolling thin products tend to induce a deflection of the web on the mandrel of the winder-winder.

  in relation to the axis of the rolling mill. This trend is further

  so much more sensitive that the products in 700 mm width are obtained by slitting into two hot rolled strips in width of 1400 mm, which results, on the strips, for reasons inherent in the hot rolling processes, by a difference thick from one bank to the other, which favors the phenomenon. To ensure the lateral stability of the laminated strip, generally a strip of paper is interposed in the reel at the time of winding of the latter and at each rolling phase. However, the cost of paper is high, which greatly increases the cost of laminating. In addition, the length of the paper rolls is, when laminating extra-thin products much shorter than the length of the product to be laminated, which requires

  slowdowns during rolling for "stunted

  of paper. These slowdowns are prejudicial

  targets for productivity but also for quality, in particular the rolling tolerances which are

  always worse in transient regimes.

  The object of the present invention is therefore to dissociate the winding traction function from the rolling traction function, and thus to achieve simultaneously in the same rolling mill of thin or extra-thin sheets or strips rolling and a winding traction which is weak or moderate, so that the latter does not cause any quality defect on the product. To this end, the present invention has for

  object a cold rolling device for the pro-

  duction of thin and extra-thin sheets, comprising

  a winder-unwinder, at least one laminate cage

  classic black i multi-cylinder, and a winder-

  rewinder, characterized in that it further comprises means for tensioning the strip located between the winders and independent of the latter, said tensioning means being made up of any number of rollers. whose respective Speeds are adjustable in order to allow the traction of

desired rolling.

  According to another characteristic of the invention

  tion, the rolls are staggered and interposed on the one hand between the winder-unwinder and

  the rolling stand to form a first set

  tension bead and on the other hand between the rolling stand and the winder-winder to constitute a

second set of tension.

  According to yet another characteristic of the invention, the number of rollers of each set of tensions and the contact angles of the sheet on each of said rolls are defined as a function of the coefficient of friction of said sheet and each roll, and of the ratio between the desired rolling tension and the technically winding tension

  optimal for the final quality of the product.

  The invention will be better understood using

  the description which follows, given only to

  by way of example and made with reference to the accompanying drawings, in which: - Figure 1 is a schematic view in longitudinal section of a conventional rolling mill before the introduction of the device according to the invention; - Figure 2 is a schematic view in

  longitudinal section of the same rolling mill provided with the

positive according to the invention.

  In this example, it is a question of laminating in a single pass a sheet 1 of 600 mm wide and 0.12 mm thick to bring it to a final thickness of 0.05 mm by means of a Sendzimir type cage, i.e. a multi-cylinder cage of

  support and two small working cylinders, previously

  from a winder-unwinder and followed by a

  neuse-rewinder. To obtain both the target hardening rate and the final quality sought for the product, it is necessary to exert a rolling traction on the sheet of 50 Kg mm2, and to carry out only on the winding on the output winder winding traction of

Kg mm2, or five times less.

  In the classic layout of a rolling mill

  Sendzimir type according to Figure 1, we find success

  sively, a winder-unwinder 2, a roll

  sheet metal flector 3 followed by a thickness gauge

  seur 4 disposed at the entrance of a rolling mill cage 5.

  This rolling mill cage 5 conventionally comprises support rollers such as 6 and two small working rollers 7. At the exit from the cage, a thickness gauge 8 is placed followed by a roller

  deflector 9 of the sheet 1 and of a winder-winder

se 10.

  With such a material, starting from a sheet of thickness of 0.12 mm, one can only achieve in a single operation, under good conditions of final quality, a final thickness of the sheet 1 of

0.07 mm.

  The device according to the invention shown in Figure 2, allows to obtain a sheet having a

  final thickness of 0.04 mm while creating a trac-

  lamination of 50 Kg / mm2 and tensile strength

rolling of 10 Kg / mm2.

  To this end, the device comprises a first set of tension in S 20 of the sheet 1 arranged between the reel-unwinder 2 and the cage 5

  of rolling mill, and a second set of tension in S 40.

  of the sheet 1 placed between the rolling mill stand 5 and the

winder-winder 10.

  The first tensioning assembly 20 consists of five rollers such as 21 (21a, 21b, 21c, 21d, 21e) arranged in staggered rows, each provided with an independent motor with variable speed and torque not shown, and provided with deflectors such than 22 (22a, 22b, 22c, 22d). In the example shown in FIG. 2, the roller 21d is provided with a tensile gauge 23 of the sheet 1. The position of the tensile gauge 23 depends on the number of rollers constituting

the tension assembly 20.

  Coming out of this first set of tension

  , the sheet 1 engages in the cage 5 passing through.

  the first thickness gauge 4, then between the two working rollers 7, finally in a second gauge

thick 8.

  Leaving the cage 5, the sheet 1 engages in the second tension assembly 40 identical to the first, consisting of five rollers such as 41 (41a, 41b, 41c, 41d, 41e) arranged in staggered rows, each provided with an independent motor with variable speed and torque not shown, and provided with deflectors such as 42 (42a, 42b, 42c, 42d). The roller 41d is provided with a traction gauge 43 of the sheet 1. The position of the traction gauge 43 depends on the number

  of rollers constituting the tension assembly 40.

  The number of rolls in each set of

  tension 20 and 40 and the angles of lashing, that is to say

  tell the contact angles of sheet 1 on each

  of said rollers, are defined as a function of the coefficient

  cient of friction between the sheet and each roll, and of the ratio between the desired rolling traction and the technically optimal winding traction for

the final quality of the product.

  An electronic device, not shown, intervenes at all times on the different motors of said rollers of each tension assembly 20, 40 to ensure the balancing of the motor and resistance pairs, according to the indications provided by the instantaneous traction meters 23 and 43.

  On each of the rollers, a tachymeter sensor

  stick, not shown, permanently controls the actual speed of rotation of the corresponding roller, and on the 21st roller closest to the rolling mill stand 6, a dynamometric sensor, not shown,

  continuously measures the actual traction in sheet 1.

  Each of the roller motors is powered by an analog or digital electronic variator which can

  vary speed and torque.

  A global analog regulation system

  that digital calculates continuously the reference values which it sends to each of the motor variators and which allows them to generate the currents to be applied to each of said motors, as a function of the following elements: - the value of the reference traction, - the value of the actual traction transmitted by the dynamometric sensor, - the speed of rotation of each of the rollers,

  - the value of the linear speed referenced

  ce, - the value of the actual linear speed

  transmitted by the tachometer sensor.

  This traction control operates in a closed loop and ensures constant traction at all times on the laminated sheet, this

  traction to be in accordance with the reference traction-

operator displayed.

  After having crossed the last roll 41e of the second tension set 40, the sheet 1 is wound in a reel by the winder-winder 10. This tension set 40 closest to

  the winder winder 10 ensures with said reel

  leuse coiler the desired winding traction which is 10 Kg / mm2, independently of the rolling traction. According to a variant, the rollers of each tension assembly 20, 40 are controlled by a single variable speed motor controlled by an electronic variator adapted to the type of motor. A digital or analog regulation device regulates the motor of each assembly in order to

  to adapt the overall torque applied to the conditions

operating conditions.

  In this case, the transmission of the power from the motor to the different rollers of each set is done by means of a mechanical device through a differential pulley by rollers which ensures an automatic balancing of the torques on

each roll.

  Thanks to this device, the traction of the lami-

  swimming becoming independent of winding traction-

  ment, the invention has several important advantages. First of all, the rolling of sheet metal of large width up to 700 mm, and of very thin thickness up to 0.01 mm becomes possible, while preserving a very good quality of the finished product, and such rolling becomes possible without interleaf paper this

  which greatly reduces the cost of rolling.

  In addition, a significant reduction in thickness becomes possible with a minimum number

  rolling operations, often in a single operation

  ration, and the size of the coils can, without inconvenience

  deny, be important, which improves productivity

  quickly. Finally, on the finished product it does not appear

  none of the faults often observed with the devices

  known lamination, defects such as "nerves" and "creases". The quality of the finished product is

thus-excellent in all respects.

  The device according to the invention is special-

  advantageous for rolling extra-thin sheets

  these, especially stainless steel.

Claims (7)

  1. Cold rolling device for the production of thin and extra-thin sheets (1), comprising a winder-unwinder (2), at least one cage (5) of a conventional multi-cylinder rolling mill (6, 7), a winder-winder (10), characterized in that it further comprises tensioning means (20, 40) of the sheet (1) located between the winders (2, 10) and independent of the latter, said means of   voltage (20, 40) being made up of any number   conch of rollers (21, 41) whose speeds respect   tives are adjustable in order to obtain the traction of desired rolling.   2. Device according to claim 1, characterized in that the rollers (21, 41) are staggered and interposed on the one hand between the winder-unwinder (2) and the stand (5) of rolling mill to form a first set tension (20), and secondly between the stand (5) of the rolling mill and the winder-winder (10) to constitute a second tension assembly (40).   3. Device according to claims 1 and   2, characterized in that the number of rollers (21, 41) of each tension assembly (20, 40) and the contact angles of the sheet (1) on each of said   rollers (21, 41) are defined according to the coefficient   cient of friction of said sheet (1) on each roller (21, 41), and of the ratio between the traction of   desired rolling and tensile winding techni-   only optimal for the final quality of the product.   4. Device according to one of claims   1 to 3, characterized in that the rollers (21, 41) of each tension assembly (20, 40) are at least equal together.   5. Device according to one of claims   1 to 4. characterized * n that the tension assembly (40) closest to the winder-winder (10) ensures with said winder-winder the desired winding traction independently of the rolling traction.   6. Device according to one of claims   1 i 5, characterized in that the different rollers (21, 41) of the two tensioning assemblies (20, 40) are   each controlled by an independent motor, the balance   brage of the driving torques and the resistant torques of said different rollers being regulated by a electronic device.   7. Device according to one of claims   1 to 5, characterized in that the set of rollers (21, 41) of the same tension set (20, 40) is controlled by a single motor, the balancing of the motor torques and of the resilient couples of said different rollers being obtained by differential pulleys   at the rate of one pulley per roller axis. 1 / JC m) j Q Ci., _ And '----- 1tt..7 0 1V D $ oe <'Ju e / E "l ae z oh N