FR2570623A1 - TANDEM ROLLER FOR FLAT PRODUCTS - Google Patents

Abstract

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

Description

70623

  The invention relates to a tandem rolling mill for flat products in the form of strips comprising a plurality of cages disposed one after the other and equipped with devices for adjusting the traction of the machine.

  band formed by clamping means of the rolls of the cage.

  The tandem cold rolling mills comprise a succession of cages arranged one after the other in the path of the strip which they provide a gradual reduction in thickness. The band is kept perfectly stretched in the space between two successive cages or inter-cage space. For this purpose, an adjustment is made to the tension in the band,

  in each of the inter-cages, to maintain this traction-between two val-

  their predetermined depend on the product being rolled. We are

  thus keeps the rolling conditions constant in each of the cages and

  this avoids reaching levels of traction that could

drag a rupture of the band.

  The regulation of the cold tandem train is ensured so as to ob-

  keep a perfectly consistent strip output thickness and for

  this maintains the thickness of the strip at the outlet of the first cage par-

  actually constant as well as the speeds of the first and the last cage. The speeds of intermediate cages can be deduced from these conditions because they are imposed by the law of conservation of the masses of

  metal through the rolling mill cages.

  It is therefore not possible to act on rotation speeds

  cage cylinders to adjust the traction of the belt in the inter-

  cages. Cage clamping devices are generally used to adjust the tension of the web. The rolling mill cages in fact comprise means for adjusting the clamping of the rolls of the rolling mill between which the flat product being rolled passes. These clamping devices make it possible in particular to compensate for the deformations of the

  cage under the rolling force, to maintain the thickness of the sensi-

  consistently constant at the exit of the cage. These clamping devices are con-

  usually arranged by hydraulic cylinders arranged at each of the ex-

  tremities of the cylinders through which the clamping is carried out.

  These cylinders are very often support cylinders which transmit the thrust of the hydraulic cylinders of the clamping device to the cylinders of

  job. To adjust the web tension in an inter-

2 2570623

  cage, one acts on the hydraulic clamping device of the cage which is immediately downstream of this inter-cage. For this, we measure the traction of the band in the inter-cage and this measurement is compared to two limit values between which we want to maintain traction. If one or more of the limit values is exceeded by a higher value or a lower value, the clamping system is acted on in one direction

  or in the other. In the case where the measured pull is too strong,

  tightening, resulting in lower traction upstream

  of the cage. In the opposite case, the hydraulic clamping is reduced.

  Such a method, however, has the drawback of causing variations in

  flexion of the cylinder through which the

  tightening and thus a modification of the bending of the working cylinders during

  rolling. This results in a decrease in the thickness of the product

  dish; this thickness is not constant in the transverse direction.

  The fibers of the flat product thus deform differently according to the

  width of the sheet; this results in unevenness in the direction of

  cross section and in the longitudinal direction of the sheet. It is

  therefore necessary to correct the flexing of the working rolls by

  positive bending of these cylinders which act in the opposite direction of the

  bending caused by the hydraulic clamping device.

  This set is complex and does not always make it possible to obtain a

  product with perfect flatness.

  The object of the invention is therefore to propose a tandem rolling mill for flat products in the form of a strip comprising a plurality of cages arranged one after the other and each comprising two working rolls mounted in a fixed frame between which passes the flat product during rolling and a clamping device of the work rolls

  as well as devices for measuring the traction in the flat product dis-

  placed in each of the spaces between two successive cages, or spaces

  these inter-cage, on the course of this flat product which remains perfectly stretched in the inter-cage spaces, the clamping device of a cage

  being controlled by the tensile measuring device disposed in the space

  this inter-cage located just upstream, for the adjustment of the traction of the pro-

  duit flat in this inter-cage space, this rolling mill to adjust the

  traction of the flat product in the inter-cages without creating defects of pla-

  and without requiring the use of cambering devices

working conditions.

  For this purpose, at least one of the stands of the rolling mill comprises at least one clamping device consisting of a cylinder having a fixed support mounted in the frame of the cage, a tubular casing in contact with one of the following working rolls. one of its generators and over its entire length, rotatably mounted around the fixed support and a plurality of hydraulic cylinders arranged radially between the fixed support and the tubular casing having pistons whose end located towards the inner surface of the envelope constitutes at least one chamber receiving fluid

  under pressure to form an oil film allowing rotation of the enve-

  slip by sliding on the film of oil,

  the supply of cylinders with hydraulic fluid for moving the pistons

  in the radial direction being controlled by the measuring device

  traction in the inter-cage located just upstream of the cage considered.

  In order to fully understand the invention, we will now describe

  As a nonlimiting example, with reference to the appended figures, an embodiment of a cold tandem rolling mill for products

  dishes, according to the invention, comprising four quarto cages.

  FIG. 1 is a schematic view of the cold rolling mill, in section

  by a vertical plane parallel to the direction of movement of the strip.

  FIG. 2 is a cross-sectional view of one of the cages of the

  rolling mill shown in Figure 1.

  FIG. 1 shows a cold tandem rolling mill comprising four stands 1, 2, 3 and 4 in which plate 5 passes successively

for its rolling.

  Each of the cages has two working cylinders 6 and 7 a

  lower support liner 8 consisting of a solid cylinder and a cylinder

  upper support 9 with deformable tubular envelope.

  In the inter-cages between cages 1 and 2, 2 and 3 and 3 and 4,

  are arranged successively in the path of the strip a device for

  10 and a device for measuring the tension in the strip 11. The elements relating to the cages 1, 2, 3 and 4 respectively

  will be assigned indices a, b, c and d respectively.

  Similarly, the elements relating to the three successive inter-cages

  will be assigned indices a, b and c.

  At the outlet of the cage 1 is placed a device 12 for measuring the thickness of the sheet 5. At the exit of the cage 4 is placed a roll of

  additional flatness measurement 10d.

  In Figure 2, there is shown a roll stand of the mill shown in Figure 1, the upper support roller 9 comprises a fixed support 15 mounted in the fixed frame 14 of the cage through the ends of trees

  a and 15b and spherules 17a and 17b. The roller 9 also comprises a

  tubular shoe 16 whose inner diameter is such that a clearance remains between the fixed support 15 of the roll and the inner surface of the casing 16. The fixed support 15 is machined so as to constitute five chambers 20 of

  vertical radial direction which can be supplied with hydraulic fluid

  than by a central pipe 23 also machined in the support 15.

  Pistons 21 are slidably mounted and sealed in the chambers 20 and constitute therewith cylinders holding the casing 16 in the radial direction. The pistons 21 have at their end directed towards

  the inner surface of the tubular casing 16 of the depressions 24

  nicotine with the chamber 20 fed with hydraulic fluid. The pistons 21

  therefore, when the chambers 20 of the cylinders are fed with fluid

  of hydraulic, to maintain the casing 16 in the radial direction and to create an oil film between the end of the piston and the inner surface of the casing 16. The casing 16 can thus rotate around the fixed support

practically without friction.

  The hydraulic fluid supply under pressure of the chambers

  20 cylinders is provided by a circuit 25 comprising electromechanical elements.

  control hydraulics whose opening or closing depends on the

  their tensile strength measured by the tensile measuring device 11 dis-

  placed immediately upstream of the cage considered.

  The value of the traction measured by the device 1I is comparable

  two set values between which we want to maintain this

  traction. In the case where the traction leaves the invervalle defined by the

  their set points, the pistons 21 of the cylinders are moved in one direction or

  in the other, of the same quantity, via the hydraulic circuit

  25. The set of pistons 21 thus moves the tubular casing 16 in one direction or the other without modifying the shape of the generatrix of contact between this casing 16 and the upper work roller 6. It is thus possible to modify the clamping the cage and thus adjust the traction of the strip upstream of this cage, without changing the form of contact generator and thus the setting to obtain a product of perfect flatness. This is achieved thanks to a distribution of displacement jacks

  of the casing of the support cylinder over the entire length of this cylinder.

  The clamping devices of the rolling mill cages according to the prior art

  acted only through the ends of the cylinder through

2570623

  the middle of which the adjustment was made.

  It can be seen in FIG. 1 that the setting of the different cages

  1, 2, 3 and 4 are not identical and that only cages 2, 3 and 4 have a traction control assembly in the upstream inter-cage, by displacement of the casing of the cylinder. 9. These provisions

  allow you to adjust the traction of band 5 in the three inter-

cages of the cold tandem train.

  On the other hand, the four stands 1, 2, 3 and 4 comprise an assembly allowing the adjustment of flatness and possibly the adjustment of thickness by using the deformable envelope upper support roll. For

  that, the displacements of the five cylinders arranged according to the length of the rolls.

  support beams 9 are ordered either as a whole but separately

  by a control circuit receiving the indications of a roll of glide

  10 and possibly in their entirety by a control circuit

  before the indications of a thickness gauge such as 12.

  Such a method of adjusting thickness and flatness has been de-

  written in the patent application 83-16331 of October 14, 1983 of the CLECIM Company. It should be noted that these displacements of the casing of the cylinders 9 are superimposed on the displacement due to the tightening for the traction control in the band. These movements of the different cylinders for the adjustment of

  flatness are not identical as in the case of traction adjustment.

  On the other hand, the devices for measuring thickness and flatness are dis-

  placed downstream of the cage on which the flatness adjustment is made

and thick.

  The means for adjusting the traction on the one hand and the thickness and the flatness on the other hand are therefore distinct although they do

  call to the same support roll with moving and deformable envelope.

  We could conceive. a cold tandem train where

  support rollers with a mobile casing using jacks would only serve

  setting the traction in the belt.

  The main advantages of the rolling mill according to the invention are to allow a tension adjustment of the band in inter-cages not creating

  flatness and thus avoid the use of cam-

  braking of the working rollers for the correction of these glide defects

you.

  The invention is not limited to the embodiment which has been de-

  on the contrary, it contains all the variants.

  Thus it is possible to imagine the use, in a

  a cold tandem train, means for adjusting the traction according to the invention.

  in some cages only, the other cages being equipped with

  clamping means according to the prior art. The effect of these devices

  variations in profile and flatness can indeed be very low or zero in some cages of the cold train but on the contrary very

important in other cages.

  Cages equipped with traction control means according to the invention may comprise two support cylinders with moving envelopes

  and deformable, the envelopes of these two cylinders being controlled simul-

  momentarily for their displacement leading to the clamping of the mill, from

  indications of the tensile measuring device in the inter-cage

  upstream. The support rollers with moving and deformable envelope can

  have a variable number of rooms from one cage to another.

  The tandem cold rolling mill according to the invention may comprise not only quarto cages as has been described but also cages

  having a larger number of rollers, for example sexto cages

  both cylinders intermediate the support cylinders and the cylinders

working conditions.

  In the case where it is carried out on the rolling mill stands at a time

  Tension adjustment of the web and adjustment of thickness and planarity

  the devices for measuring the traction and the flatness arranged in the inter-cages making it possible to control the adjustment means of the

  cages can be not only distinct, as in the example of

  which has been described but also confused.

  For example, it is possible to use a single roll of measurement of

  located in each inter-cage which measures the cross-sectional distribution

  the one of the traction in the band. The measurements obtained from this rou-

  the water of flatness serve on the one hand to control individually

  the cylinders of the deformable envelope bearing roller arranged upstream of the flatness roller and, secondly, to control the identical displacements of the cylinders of the deformable and movable envelope roller.

  cage disposed downstream of the flatness roller. To control the movements

  allowing traction adjustment, by clamping the cage arranged in

  downstream of the flatness roller, a signal representative of a trac-

  average in the band obtained from the indications of the different

  parts of the flatness measuring roller.

  In all cases, however, the control of the adjustment means of

  flatness and the control of the traction control means remain

7 257062

  even if the means of measurement placed between the cages and the

  actuating means arranged in the cages are common.

  The tandem rolling mill according to the invention can be used for the cold rolling of any flat product in the form of a strip that passes from one cage to another remaining perfectly stretched in the inter-cage spaces. The invention also applies to any hot tandem rolling mill whose control mode would be identical to that of a tandem rolling mill to

  cold, as regards the traction of the product during rolling.

70623

Claims (5)

  1.- Tandem rolling mill for flat products in the form of a strip   carrying a plurality of cages (1, 2, 3, 4) arranged one after the other and each having two working rolls (6, 7) mounted in a fixed frame (14) between which the product passes flat (5) being rolled and a clamping device for the work rolls (6, 7) as well as devices for measuring the traction in the flat product (11) arranged in each of the spaces situated between two successive cages or inter-cages spaces, on the course of this flat product (5) which remains perfectly stretched in the spaces between cages, the -dispositif of tightening a cage   being coanded by the tensile measuring device disposed in the space   this inter-cage located just upstream for adjusting the traction of the pro-   flat duit (5) in this inter-cage space, characterized in that at least one of the stands of the rolling mill (2, 3, 4) comprises at least one clamping device (9) consisting of a cylinder   having a fixed support (15) mounted in the frame (14) of the cage, an envelope   tubular pe (16) in contact with one of the working cylinders (6, 7)   one of its generators and over its entire length, rotatably mounted around the fixed support (15) and a plurality of hydraulic cylinders (20,   21) arranged radially between the fixed support (15) and the tubular casing   re (16) comprising pistons (21) whose end located towards the inner surface of the casing (16) constitutes at least one chamber (24) receiving oil under pressure to form an oil film allowing the rotating the casing (16) by sliding on the oil film, supplying the cylinders (20, 21) with oil for moving the pistons (21) in the radial direction being controlled by the measuring device   traction (11) in the inter-cage just upstream of the cage considered   SOE. 2. A tandem mill according to claim 1,   characterized in that it comprises quarto cages having two rings   working rolls (6, 7), a one-piece support cylinder (8) and a cylinder   support member (9) with a moving and deformable envelope held in the radial direction   by hydraulic cylinders (20, 21) whose pistons (21) are   for their simultaneous movement by a hydraulic circuit (25), according to the indications of the traction measuring device (11) disposed   in the inter-cage immediately upstream of the cage on which kills the setting. 9 2570623   3. Tandem rolling mill according to claim 1,   characterized by having quarto cages having two cylinders   working drums (6, 7) and two supporting cylinders (9) with a moving envelope and   deformable in contact with each of the respective work rolls (6, 7)   whose movable casing 16 is held in the radial direction by hydraulic cylinders (20, 21) whose displacement of the pistons (21)   simultaneously and of the same quantity is controlled by a hydraulic circuit.   that (25), according to the indications of a tensile measuring device (11) of the strip (5) in the inter-cage space disposed immediately in upstream of the cage considered.   4. Tandem rolling mill according to claim 1, characterized in that it comprises, downstream of each of these cages (1,   2, 3, 4) of flatness measuring devices (10) and that the control cylinder   pui (9) with a mobile and deformable envelope in each of the cages is used for the flatness corrections, the pistons (21) of the hydraulic cylinders   (20, 21) for holding the casing (16) of the supporting cylinder (9)   mobile and deformable pe (16) being individually controlled by a cir-   hydraulic cooking, according to the indications of the flatness measuring device (10) disposed in the inter-cage disposed immediately downstream of the cage considered.   5. Tandem rolling mill according to Claim 4, characterized in that the tensile measuring device (11) in   at least one of the inter-cages is constituted by a platen measuring roller.   to determine the value of the traction in the belt in   different places of its width, the clamping device of the cage   placed immediately downstream of the flatness roller constituted by the cylinder   deer (12) with a deformable envelope (9) being controlled from an average value of the traction obtained from the values of the traction   measured by the flatness roller. NINE CLEGCIM PAGES