EP2769779A1 - Facility and method for rolling a metal strip - Google Patents

Abstract

The installation has a rolling mill (7) through which a metal strip (3) is rolled as it passes continuously. A decontamination module (8) is arranged with a degreasing unit and is positioned between an outlet of the rolling mill and a set of strip drawing unit (9, 9'). A strip accumulator (10) is positioned at an outlet of a part of the drawing unit so as to keep the speed of travel of the strip at the outlet of the accumulator below a maximum threshold. A paper strip insertion module is positioned downstream of the outlet from the accumulator. An independent claim is also included for a method for application of a metal strip rolling installation.

Description

The present invention relates to an installation and method for rolling a metal strip according to the preamble of claim 1.

The metal strip rolling mills, in particular cold-formed and capable of rolling strips mainly made of stainless steel, requires the use of a high-capacity mill (> 400,000 tons per year) such as a tandem mill. The rolling is carried out continuously (i.e., the web is continuously moving) to limit the costly loss of time and material during the introduction and release of web (such as for a discontinuous mill. upstream of the rolling mill, the use of a welder makes it possible to connect successive tails and band heads together in a unwinding section made by at least one uncoiling machine Downstream of the rolling mill or at least at the end of a complete rolling line it is finally required to separate these strips to wind them into separate coils by means of at least one winder.

The surface condition of the web is a critical component of web quality through a complete lamination line, so frequent visual inspections are most often required.

Rolling plants such as those of the tandem type (adapted for carbon and stainless steel strips) are preferably equipped with double coils, placed at the downstream outlet of the rolling mill) and downstream of a shear for cutting the strip preferentially to the fly and separate it by forming disjoining bands to wind them alternately on preferentially two mandrels exerting on the belt upstream of the winding a specific traction to the conditions required for a good winding, a good bobbin behavior once output of the winding mandrel and the subsequent unwinding constraints on multiple lines of operation downstream of the operation rolling. The strip tension required for the winding is generally different from that required by the rolling operation: the strip tension associated with the rolling is generally greater or even much greater than the strip tension necessary for the winding, during the cutting and the transfer of the roll. the head of a belt to its winding machine, traction is generally established or permitted only by means of a traction unit such as a nipper capable of establishing a lower pull than the desired web tension rolling mill output for good rolling conditions, which can induce a disruption of the strip thickness and a generation of final product out of tolerance to be downgraded and often not usable, which is very expensive especially in the case of production of lamination. 'stainless steel. Likewise, the mill roll speed at the output of the rolling mill must be reduced during operations downstream of the rolling mill outlet, especially during cutting of the strip (shearing, beginning of winding on a mandrel, introduction of paper tape between turns of coil in stainless steel production, inspection, etc.), which induces a significant loss of productivity and also a qualitative impact on the factors of the rolling process, which generate defects in the thickness and flatness of the outgoing band of the rolling and in general all degraded qualitative factors well known by the effect of transient regimes of variations in speed and / or low speed. In the field of stainless steel strips, the insertion of a sheet or film of paper between the turns of the resulting coils requires a very low transfer / insertion speed, for example of the order of 30 to 60 m / min. / or the use of complex and expensive machinery to insert this sheet on the fly at a speed of for example 60 to 100 m / min.

This reduction in speed induces a decrease in the rolling productivity and also an increase in the rolling force which may cause difficulties for the parameters of the rolled out product.

• un laminoir dans lequel la bande est laminée en défilement continu,
• une unité de traction de bande disposé en sortie de laminoir.

A rolling mill from Nisshin Steel Company Limited (publication GB1313577 ) has been described, presenting a tandem type mill for continuous production of a stainless steel band. The rolling mill is equipped in tandem with successive rolling mills (type 20-high), which certainly require longer, non-automated cylinder changing times, but also duo-clamping tensioning units upstream and downstream of the rolling mill. and which can cause surface defects, thickness or flatness on the strip. This installation is however a good basic example of the present invention, in that it describes a rolling installation of a metal strip comprising at least:

• a rolling mill in which the strip is rolled in continuous scrolling,
• a strip traction unit disposed at the output of the rolling mill.

It should be noted that the present invention also provides for consideration of lubrication and internal cooling means on the rolling mill (on rolls of rolling mill and thus on the strip) in order to guarantee a predefined ratio of rolling, crushing and sliding of the rolling mill. band between the rollers under the contact arc strips on rolling rolls. In fact, these make it possible to obtain a lubrication / cooling rate that is useful for rolling in the rolling mill so as, on the one hand, to cool the rolled strip and on the other hand to make it possible to reach under good conditions and under the rolling force, a desired ratio between the rolling, crushing and sliding of the strip running in the rolling mill.

At the outlet of the rolling mill, the strip has a surface retention, residual rolling agents such as traces of oil and other elements of coolant of the rolls and tape used for the rolling process, as well as fats coming from various possible contributions. Due to the presence of oil, other grease or other on the strip, it can not be easily exerted on the strip at the output of the rolling mill, a significantly strong tensile stress, for good rolling conditions. The traction being generated by a traction unit at the output of the rolling mill such as tensioning rollers and / or roller clamping means, these traction elements are necessarily coated by accumulation of oil, other grease or other residual , which inevitably reduces the coefficient of friction and adhesions necessary to exert traction on the band. Also, sliding phenomena cause and promote lateral deviations of the tape along its path to the winder (for example in a battery at the exit of the rolling mill and / or on the winder) which generate consequent drops in productivity. This case then requires means to combat and correct these band position deviations which induce a real lack of mastery of the tape running characteristics such as non-precision qualities of traction, accumulation, and / or winding, in particular on fields of the coils. The oil, other fatty substances or other residual remaining on the strip surface at the end of the mill also have a pollution factor on the final cleanliness of the strip degrading its final quality and disturbing the mechanical properties and clean preservation of the strip. of paper necessary for the winding of tape in the particular case of stainless strips to be wound.

An object of the present invention is to propose an installation and a method of rolling a high productivity metal strip, by guaranteeing an increased control of band running characteristics independently of the operations made at the rolling output and especially from at least one traction unit downstream of a rolling mill to a final winding downstream of the traction unit.

In this sense, the installation according to the invention should in particular allow better productivity for a predominantly stainless type strip. In this respect, knowing that a web winding comprising an insertion of an interleaved paper film is usually made at the end of a rolling line to protect the strip surface between coiled turns, the installation according to the invention should allow a simpler, more robust and reliable paper film insertion.

Such an installation is proposed through the features of claim 1, as well as a method through claim 12.

A set of subclaims also has advantages of the invention.

An exemplary embodiment of the installation and application of the method according to the invention is provided using the figure 1 and its description below. An output variant of said installation of the same embodiment is also presented in figure 2 .

• un laminoir (7) dans lequel la bande (3) est laminée en défilement continu (dans le sens de la flèche sous la référence 3),
• des agents de laminage mis en contact avec des cylindres du laminoir et avec la bande, les dits agents comprenant au moins un moyen de lubrification et de refroidissement interne de cylindres de laminage (disposés communément dans au moins une cage du laminoir (7); ici 5 cages sont représentées) afin de garantir un rapport optimum prédéfini entre les propriétés de roulement, d'écrasement et de glissement de la bande entre les cylindres de laminage,
• une unité de traction (9) de bande disposée en sortie de laminoir, la dite unité de traction étant une partie d'un ensemble d'une pluralité d'unités de traction (en figure 1 seules deux unités de traction 9, 9' sont représentées pour des raisons de clarté) distribuées entre la sortie de laminoir jusqu'à une sortie de l'installation telle qu'une bobineuse (13, 14) ou une ligne couplée de traitement métallique (non représentée),

l'installation selon l'invention se caractérise en ce qu'un module de dépollution (8) comprenant au moins un moyen de dégraissage, suivi préférentiellement d'un moyen de brossage, rinçage et de séchage, est disposé entre la sortie du laminoir et l'unité de traction, afin d'éliminer de la bande les dits agents résiduels en sortie de laminoir.From a rolling plant of a metal strip (3) represented in figure 1 comprising at least:

• a rolling mill (7) in which the strip (3) is rolled continuously (in the direction of the arrow under the reference 3),
• laminating agents contacted with rolls of the rolling mill and with the web, said agents comprising less a means for lubricating and internally cooling rolling rolls (commonly arranged in at least one roll stand (7), here stands are shown) in order to guarantee a predefined optimum ratio between rolling, crushing and slip of the strip between the rolling rolls,
• a pulling unit (9) of strip disposed at the output of the rolling mill, said pulling unit being a part of an assembly of a plurality of traction units (in figure 1 only two traction units 9, 9 'are shown for reasons of clarity) distributed between the rolling mill outlet and an outlet of the plant such as a winder (13, 14) or a coupled metal treatment line ( not shown),

the installation according to the invention is characterized in that a depollution module (8) comprising at least one degreasing means, preferably followed by a brushing, rinsing and drying means, is arranged between the exit of the rolling mill and the traction unit, in order to eliminate the said residual agents at the output of the rolling mill.

Advantageously, at the outlet of the depollution module (8), the strip has an increased adhesion and therefore a better controlled trajectory when it passes over deflection rollers and at the inlet of each of the traction units (9, 9 '), an accumulator (10) downstream of at least a portion (9) of the traction units (9, 9 ') and other installations downstream of the rolling mill. Deviations, in particular lateral deflections, of strip paths are thus avoided, because an increased mastery of tape running characteristics is therefore achieved independently of the operations made at the rolling output and especially since at least the first traction unit (9 ) downstream of the rolling mill to a final winding (13, 14) downstream of the traction unit. Also for the same reason of increased adhesion, means of tape clamping (in addition or worse in substitution of rollers rollers ("bridle rolls" in English) as those of the traction unit 9) are thus little necessary or avoidable. Thus, the traction unit (9, 9 ') may comprise only tensioning rollers of the moving web for exerting a majority tensile tension, in particular said unit possibly being able to comprise only a pinching means for exerting an auxiliary tension. minority or even nil. As a result, there are fewer band defects incidentally induced by pinching means, hence higher productivity and quality. The fact of being able to better control the trajectory characteristics of the scrolling tape, or even to limit or even cancel the number of nipers, also makes it possible to increase the speed of movement of the tape "better guided and without actively guiding elements like pincers" until to the accumulator (10) downstream of the rolling mill. Here again, the strip rolling productivity can be considerably increased.

• il a été vu qu'une vitesse accrue de défilement dans le laminoir (7) est permise jusqu'à l'accumulateur (10) selon l'invention en raison de la meilleure maitrise de trajectoire de bande en sortie de laminoir. L'accumulateur (10) de bande étant disposé en sortie d'au moins une « première » partie (9) des unités de traction (9, 9'), il permet ainsi en particulier de maintenir une vitesse de défilement de bande en sortie du laminoir et du dit accumulateur sous un seuil maximal, voire d'atteindre une faible vitesse ou une immobilisation de faible durée en sortie du dit accumulateur. Bref, cette réduction de vitesse en aval de l'accumulateur permet alors avantageusement de pouvoir réaliser, en sortie d'installation selon l'invention, une inspection (voir module d'inspection visuelle/optique/acoustique/mécanique/etc. (11) de bande disposé en aval de la sortie de l'accumulateur (10) de bande), un cisaillage (12), un passage de bande d'une bobineuse (13) sur une autre bobineuse (14), etc. sur une portion de bande quasi voire complètement immobile. Les moyens mis en oeuvre pour réaliser ces opérations d'inspection, cisaillage, introduction de bande de papier à l'enroulement, etc. sont alors plus simples que ceux mis en oeuvre si la bande défile à plus haute vitesse. Par exemple, la sortie de l'accumulateur (10) peut être simplement couplable à une entrée d'une bobineuse (13) pour laquelle est disposée en son amont une cisaille (12) pouvant couper la bande à l'arrêt. Dans le cas des figures 1 et 2 ayant une sortie d'installation plus dynamique en raison de la productivité accrue du laminage, la sortie de l'accumulateur (10) est couplable à une entrée de deux bobineuses (13, 14) ou (13, 14, 15 selon fig. 2) pour lesquelles est disposée en leur amont une cisaille (10) pouvant couper la bande (en défilement) à la volée, en particulier les deux bobineuses étant disposées soit indépendamment (figure 1) soit en duo sur un tambour carrousel (15) (voir figure 2). Ainsi, figures 1 et 2 présentent des moyens de bobinages en continu adaptés au but de forte productivité de l'invention.
• un module d'insertion de bande papier (non représenté pour des raisons de clarté) est disposé en aval de la sortie de l'accumulateur (10) de bande. Etant donné que l'accumulateur permet à sa sortie une forte diminution de vitesse de bande (inversement à la vitesse fort élevée d'entrée de bande dans l'accumulateur), le dit module d'insertion ne doit pas être complexe contrairement à un module plus sophistiqué et onéreux nécessaire pour de plus hautes vitesses de bande. Il en résulte aussi une plus grande simplicité, robustesse et fiabilité du procédé de bobinage de bande. Ceci est donc un avantage certain dans le cas des bandes en acier inoxydables.

The installation according to the invention is particularly well suited to a high productivity of final product for a continuously moving strip mainly comprising a stainless metal. Indeed, two advantageous aspects are observable:

• it has been seen that an increased speed of travel in the rolling mill (7) is permitted up to the accumulator (10) according to the invention because of the best control of the strip path at the exit of the rolling mill. The strip accumulator (10) being arranged at the output of at least one "first" part (9) of the traction units (9, 9 '), it thus makes it possible in particular to maintain an output bandwidth rolling mill and said accumulator under a maximum threshold, or even to reach a low speed or immobilization of short duration at the output of said accumulator. In short, this reduction in speed downstream of the accumulator then advantageously makes it possible to carry out, at the output of the installation according to the invention, an inspection (see visual / optical / acoustic / mechanical / etc inspection module (11). of tape disposed downstream of the output of the tape accumulator (10), shearing (12), webbing of a winder (13) on another winder (14), etc. on a band portion almost or even completely immobile. The means used to perform these inspection operations, shearing, introduction of paper tape to winding, etc. are then simpler than those implemented if the band scrolls at higher speed. For example, the output of the accumulator (10) can be simply coupled to an input of a winder (13) for which is disposed upstream a shear (12) can cut the band at rest. In the case of figures 1 and 2 having a more dynamic installation output due to the increased productivity of the rolling, the output of the accumulator (10) is couplable to an input of two winders (13, 14) or (13, 14, 15 according to Fig. 2 ) for which is disposed upstream a shear (10) can cut the web (scrolling) on the fly, in particular the two winders being arranged either independently ( figure 1 ) in pairs on a carousel drum (15) (see figure 2 ). So, figures 1 and 2 present means of continuous windings adapted to the purpose of high productivity of the invention.
• a paper tape insertion module (not shown for the sake of clarity) is disposed downstream of the output of the tape accumulator (10). Since the accumulator enables its output to be greatly reduced in band speed (conversely at the very high band input speed in the accumulator), the insertion module must not be complex, unlike a module more sophisticated and expensive necessary for higher tape speeds. This also results in greater simplicity, robustness and reliability of the tape winding process. This is therefore a definite advantage in the case of stainless steel strips.

The installation according to the invention provides a control module of the degreasing unit that can be controlled by parameters of the installation and the physical properties of the moving strip, such as at least one lubrication rate imposed on the rolling mill. (7) and a maximum band rolling factor guaranteed by the traction unit (9, 9 '). This control system thus allows a more refined optimization of adjustment of the depollution module in order to achieve a more economical depollution in terms of the use of degreasing products or other depolluting agents while ensuring an optimal depollution (therefore environmentally desirable) to achieve better control of traction and trajectory of band and a higher productivity.

The installation according to the invention comprises successively from its main inlet and upstream of the rolling mill, at least one uncoiler (1, 2), a welder (4), an accumulator (6), at least one traction unit (5, 5 '). Here again, these coupled elements allow high speeds of travel upstream of the rolling mill, knowing that the invention makes it possible to increase the running speed of rolling with increased productivity, because of better control of the strip path downstream of the rolling mill. rolling mill.

Finally, the installation according to the invention may comprise downstream of the traction unit (9, 9 ') at least one so-called APL type line (derived from the "Annealing Pickling Line" in English, as well as other types underlining CAPL "Cold Annealing Pickling Line" is directly coupled in scrolling Continuous strip is coupled via at least one coiler downstream of the traction unit to a CAPL line-entry uncoiler. A direct coupling has a disadvantage of speed of scrolling, because line CAPL imposes tape running speeds much lower than those reached by the installation according to the invention. This is why a coupling of the installation according to the invention with a CAPL line is now more attractive for high productivity by means of separate coiler / uncoiler couplers, then a transfer of the coils at the outlet of the installation according to the invention. invention to at best several distinct lines of the CAPL type.

• dans une première étape, la vitesse de défilement de bande dans un laminoir (7) jusqu'à l'entrée de bande dans un accumulateur (10) an aval du laminoir atteint un maximum de vitesse telle que 400 à 600m/min ;
• dans une deuxième étape de courte durée, l'accumulateur (10) amorce un dégagement de bande vers au moins une bobineuse (13, 14) sous une vitesse réduite à celle de la première étape telle que de 30 à 60 voire de 100m/min;
• dans une troisième étape, après échéance de la dite courte durée, la bobineuse amorce une vitesse maximale d'enroulement de bande, tel que supérieure à 550m/min voire 750m/min.

A method of implementing the installation according to the invention is also proposed, for which:

• in a first step, the tape running speed in a rolling mill (7) to the web entrance in an accumulator (10) downstream of the mill reaches a maximum speed such as 400 to 600m / min;
• in a second short-duration step, the accumulator (10) initiates a band clearance to at least one winder (13, 14) at a speed reduced to that of the first step such as 30 to 60 or even 100m / min ;
• in a third step, after expiry of the said short duration, the winder initiates a maximum strip winding speed, such as greater than 550m / min or 750m / min.

It emerges from the three steps mentioned above that the flexibility of adaptation of the rolling mill speed (high speed), the accumulator output (low speed) and then the winding (high speed) speeds tend to greatly increase the overall productivity of the machine. installation. The given speed ranges are examples provided on the current technology: deviations from these intervals are well understood possible, the invention can not limit its application and protection at these intervals.

Advantageously, this method allows inspection (11) and shearing (12) which are performed during the second step while the tape running speed is reduced.

In the same manner, the method according to the invention allows a paper sheet insertion on the tape also initiated during the second step while the tape speed is reduced.

Claims (14)

Rolling plant for a metal strip (3) comprising at least: - A rolling mill (7) in which the strip is laminated in continuous scrolling, - rolling agents brought into contact with rolls of the rolling mill and with the strip, a traction unit (9, 9 ') of strip disposed at the output of the rolling mill, characterized in that
a depollution module (8) comprising at least one degreasing means is disposed between the output of the rolling mill and the traction unit, in order to eliminate the said residual agents at the output of the rolling mill. Installation according to claim 1, wherein the band mainly comprises a stainless metal. Installation according to one of Claims 1 to 2, for which a strip accumulator (10) is arranged at the outlet of at least one part (9) of the traction unit (9, 9 '), in particular for maintaining a speed band running output of said accumulator under a maximum threshold, or even achieve a low-end immobilization output of said accumulator. Installation according to claim 3, wherein the output of the accumulator (10) is couplable to an input of a winder (13) for which is disposed upstream a shear (12) can cut the band at rest. Installation according to claim 3, for which the output of the accumulator (10) is couplable to an input two winders (13, 14) for which is disposed upstream a shear (10) which can cut the strip on the fly, in particular the two winders being arranged either independently (13, 14) or in pairs on a carousel drum ( 15). Installation according to one of claims 3 to 5, comprising a paper strip insertion module disposed downstream of the output of the tape accumulator (10). Installation according to one of claims 3 to 6, comprising a strip inspection module (11) arranged downstream of the output of the tape accumulator (10). Installation according to one of the preceding claims, comprising a control module of the degreasing unit that can be controlled by parameters of the installation and physical properties of the moving strip, such as at least one lubrication rate imposed on the rolling mill. (7) and a maximum band rolling factor guaranteed by the traction unit (9, 9 '). Installation according to one of the preceding claims, in which the traction unit (9, 9 ') comprises tensioning rollers of the moving web for exerting a majority tension pull, in particular said unit comprising a pinching means for exerting traction. Minority or even none. Installation according to one of the preceding claims, comprising at least one uncoiler (1, 2), a welder (4), an accumulator (6), at least one traction unit (5, 5 ') upstream of the rolling mill. Installation according to one of the preceding claims, comprising, downstream of the traction unit (9, 9 '), at least one line CAPL which is directly coupled in continuous strip travel or is coupled via at least one coiler downstream of the traction unit. up to a CAPL line-entry unblocker. Method for implementing the installation according to one of the preceding claims, for which: in a first step, the tape running speed in a rolling mill (7) up to the tape entrance into an accumulator (10) downstream of the rolling mill reaches a maximum speed such as 400 to 600 m / min; in a second short-duration step, the accumulator (10) initiates a band clearance to at least one winder (13, 14) at a speed reduced to that of the first step such that from 30 to 60 or even 100m / min; - In a third step, after expiration of the said short duration, the winder initiates a maximum strip winding speed, such as greater than 550m / min or 750m / min. Method according to claim 12, wherein inspection (11) and shearing (12) are performed during the second step. A method according to claim 12 or 13, wherein a paper sheet insertion on the web is initiated during the second step.

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