KR101920584B1 - Combined pickling and rolling plant for pickling and rolling metal strips - Google Patents

Abstract

Pickling and rolling plants for pickling and rolling of metal strips include continuous pickling lines; Storage means (20, 20 ') having a capacity of 1000 to 3000 meters of strip length for storing pickled strips; A reversible rolling mill having at least two first stands (19) downstream of said storage means (20); Downstream of said at least two first stands, a first reel (21) for winding a coil having a weight of 100 to 300 tons and a diameter of up to 6 meters for winding the strip after the odd rolling step; A welder (2 ') arranged between the pickling line and the first stand; At least one second reel (16) upstream of the first stand and downstream of the welder (2 ') for winding at least a portion of the strip after an even rolling step opposite to the odd number step, said at least one second reel (16) having a size to take up a strip portion having a specific weight of from about 1 mm to about 21 kg / mm; A first cutting means arranged between the second reel and the first stand (19) and configured to cut the rolled strip each time a strip portion with a specific gravity of 15 kg / mm to 21 kg / mm is wound on a second reel 22,23); The welder 2 'is configured to weld the head of the rolled strip cut by the first cutting means to the strip head to be rolled.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a combined pickling and rolling plant for pickling and rolling metal strips,

The present invention relates to a combined pickling and rolling plant for pickling and rolling metal strips.

The first fully continuous rolling mill in the cold rolling sector was manufactured in the 1970s and 80s, followed by the first combined pickling and rolling plant.

The advantage of a continuous rolled strip by a rolled weld joint is that in terms of plant productivity there is a 20% to 100% increase in productivity per hour of surface quality or rolled kiln, resulting in defects during the step of feeding the head and discharging the rolled tail In terms of performance, has a significant advantage by reducing the loss of head and tail material due to off-thickness.

This solution is that continuous pickling is directly connected to a series cold mill with four or five rolling stands to provide a plant with increased investment costs and high production capacity, typically in excess of one million tonnes per year.

The disadvantage of this solution is that the yield is limited to the plant's "bottleneck", based on the length of the product to be rolled each time, depending on the size and weight of the coil, It may be a plant input, pickling process, accumulation and rolling mill associated with the maximum speed that can be represented by a serial mill in relation to speed.

In combination with the demand for increasingly thinner thickness, the development of materials such as particularly durable steels has led to the development of new continuous mills coupled to pickling lines. For example, the bent arrangement of both plants is made so that the unwind reel of the pickling line is close to the winder of the mill. As a result, the reduction can be completed and the rolled coil can be fed at the inlet of the pickling line to achieve an increased number of reductions in the rolling mill. This configuration has a defect associated with a significant reduction in production capability because it is necessary to provide multiple passes to finish the coil to the desired thickness.

The alternative applied by a particular manufacturer was one of the so-called " jumbo coils ", one of rolling in weight over 60 tonnes and in certain cases close to 3 meters in diameter. This system, used in discontinuous tandem mills, gradually increases productivity by increasing the value obtained using a continuous mill, improving performance and partially improving surface quality.

The advantage of this solution is that the investment cost of the rolling plant is reduced, but it is a significant cost for the coil handling structure, such as roads and corresponding overhead cranes, which must be sized to continue to support these increased loads upstream and downstream of the plant It costs money.

An alternative to series cold mills is one of the reversible mills, which is usually implemented for small production capacity and accurately:

- 100,000 to 400,000 tons per year for single-stand reversible rolling mills;

- 200,000 to 1,000,000 tons per year for double-stand reversing mills.

Due to its nature, the rolling on the reversible rolling mill involves a performance degradation of the material in relation to a series mill with several stands because the rolling head and tail are rolled or partially rolled. In addition, the possibilities are eliminated in reversible rolling mills which control the surface finish of the discharge strips, as obtained in series mills. This is because it is not desirable to replace the rolling stand before performing the final pass for the purpose of delivering roughness to the surface of the strip and it is very complicated and expensive to use other emulsion systems to reduce surface contamination.

Various procedures and innovations have been attempted to improve the performance of the reversing mill:

- equipment and corresponding automation development to obtain the supply of the head and the exit of the tail with the stand closed;

- Implement a spot welder to weld the head of the coil to the leading strip, ie to the stretch of the unstretched strip, to allow the supply and closure of the stand to be produced as soon as possible.

These techniques have had partial consequences because their applications include the obvious hardening of the rolling mill operating conditions and the possible risk of damage to the rolling rollers.

Examples of combined pickling and rolling plants for metal strips with reversing mills are described in the reference [US2012 / 0272703A1].

Therefore, there is a need to provide a combined pickling and rolling plant and a corresponding process that can overcome the above mentioned deficiencies.

The main object of the present invention is to provide a composite pickling and reversible cold rolling plant with a low investment cost that allows the quality, productivity and performance of the material to be comparably obtained with those of a 4- or 5-stand serial mill coupled with continuous pickling .

 It is another object of the present invention to provide a plant that is compatible with conventional coil handling structures by allowing the coils of strips of 15 kg / mm to 21 kg / mm specific weight to be obtained.

Another object of the present invention is to provide a plant in which a reversible rolling process is provided so that the surface finishing required for plates for automobiles and household appliances can be controlled.

Accordingly, the present invention proposes to achieve this objective by providing a combined plant for pickling and cold rolling metal strips, according to claim 1,

A pickling line for continuous pickling of the strip;

Storage means for storing the pickled strips disposed downstream of the pickling line;

A reversible cold rolling mill having at least two first rolling stands disposed downstream of said storage means;

A first reel disposed downstream of said at least two first rolling stands, for winding the strip after a first rolling step;

- at least one second reel disposed upstream of said at least two first rolling stands to wind up at least a portion of the strip after a second rolling step opposite to the first step, The at least one second reel being sized to take up a portion of the strip up to a diameter limit;

- each time a portion of the strip wound on the at least one second reel reaches the predetermined weight or diameter limit of the coil, between at least one second reel and the at least two first rolling stands A first cutting means configured to cut the rolled strip;

Said storage means having a capacity of 500 meters to 3000 meters of strip length,

The first reel is sized to take up a coil having a weight of 100 to 300 tons and / or a diameter of up to 6 meters,

A welder is disposed between said storage means and said at least two first rolling stands,

Wherein the at least one second reel is disposed downstream of the welder,

The welder is characterized in that the head of the rolled strip discharged from the second rolling step obtained from the cutting performed by the first cutting means is configured to be welded to the strip head coming out of the storage means.

A second aspect of the present invention provides a pickling and cold rolling process for pickling and cold rolling a metal strip carried out by the plant as described above,

a) continuously pickling the strip by a pickling line;

b) storing the continuously picked strip by a storage means having a capacity of 500 meters to 3000 meters of strip length;

c) performing a first rolling step of a predetermined amount of strips in at least two first rolling stands and continuing to a first reel phase of the coil with a weight of 100 to 300 tons and / or a diameter of up to 6 meters Performing winding;

d) performing a second rolling step in at least two first rolling stands in a direction opposite to the first step of said predetermined amount of strip, defining a rolled strip and positioning at least one of the first portions of the rolled strip Performing winding to a second reel up to a predetermined weight limit or diameter limit of the coil to define a first rolled coil;

e) cutting the rolled strip by the first cutting means after formation of the first rolled coil;

f) winding other portions of the rolled strip onto the at least one second reel up to a predetermined weight limit or diameter limit of the coil, defining another rolled coil, and after forming each of the other rolled coils, 1 cutting the strip rolled by the cutting means;

g) welding the head of the rolled strip discharged from the second rolling step obtained from the final cutting performed by the first cutting means with a strip head coming out of the storage means, by a welder; And

h) repeating steps b) to g) while continuing with step a).

The present invention provides continuous rolling of the megacoils in the first rolling step or the odd rolling step to obtain a two or three thickness reduction.

A mega coil is a coil of a strip obtained from at least 4 to 15 welds of a small strip having a weight of 100 to 300 tons and a diameter of 4 to 6 meters.

In a first variant of the invention, when the first take-up reel downstream of the mill reaches a predetermined maximum weight or maximum diameter, the strip entering the mill is cut off, separating the mill from the pickling line. Preferably, the above-mentioned mega coil is wound into the first reel after the first rolling step.

The pickling line is connected to an increased capacity outlet storage means (equivalent to about two to three typical coils of 500 m to 3000 m of strip length, preferably at least 2000 m, size or weight of about the size or weight of the mega coils) Continue the strip process during storage. In this first variant of the invention, this increased capacity storage means comprises at least one movable carriage comprising at least three idler rollers at one end to define the serpentine path of the pickled continuous strip, And a horizontal storage portion including an idler roller fixed to the opposite end portion. By movement, the moveable carriage can increase the stored strips. The pickled strip is supported by a suitable support roller and deflected by a diverter roller located at the opposite end of the carriage.

On the other hand, by reversing the rolling direction, the mill performs a second rolling pass with a reduction in thickness twice or three times. When the second take-up reel upstream of the mill reaches a predetermined weight limit or diameter limit, the strip is cut and the first coil is unloaded. This operation is continued to produce four or five coils having a specific gravity of, for example, 15 kg / mm to 21 kg / mm (kg per mm of strip width). The size and / or weight of the final coil on the second reel is fixed at the automation level by setting the weight limit and the diameter limit. The first of the two limits reached by the coil on the second reel activates the cutting by the first cutting means.

After finishing the preparation of the final coil, the process is restarted with the previously cut strip head and a new rolling step or odd number step is started.

The conditions of the continuous rolling are generated in a first (odd) pass by inserting a welder at the entrance of the mill and leaving a tail from the previous mill that can be welded to the head described above.

In the case of the second (even) pass, continuous rolling is also achieved in the second stage by providing a carousel of double take-up reel or reel upstream of the mill with a flying shear.

At the end of the second step, the pickling line and the reversing mill are combined again and the continuous rolling is resumed in the first step.

Another advantage of the present invention is that by providing the increased capacity storage means between the pickling line and the mill and separating the two plants prior to the second rolling pass, certain " bottlenecks " Thereby allowing for increased productivity.

In a second variant of the invention, an increased capacity storage means is provided instead between the pickling line and the reversing mill, and the size of the coils (mega coils) having a weight of 100 to 300 tons and a diameter of up to 6 meters And at least one second reel. Preferably, two third reels may be provided integrally with the rotating platform configured to rotate by 180 DEG about the vertical axis after a predetermined time to wind the mega coil to one of the two third reels, 1 is used as a take-up reel for winding up a strip coming out from the pickling line and a second third reel is used as a take-up reel for taking up the strip to be fed to the rolling mill. In this variation, the welder disposed between the pickling line and the first rolling stand performs pre-welding and welding operations only, and does not cut the strip to separate the rolling mill from the pickling line. In this case, the separation is accomplished by the second cutting means upstream of the rotating platform and by the rotating platform itself. The dependent claims describe preferred embodiments of the present invention.

Other features and advantages of the present invention will become more apparent from the following detailed description of a preferred but not exclusive embodiment of a combined pickling and rolling plant, disclosed as a non-limiting example, with the help of the accompanying drawings:
Figure 1 shows a schematic view of a first embodiment of a plant according to the invention.
Figure 2 shows an example of a rolling sequence for the first (odd) stage.
Figure 3 shows an example of a rolling sequence for a second (even) stage with a static cutting shear.
Figure 4 shows an example of a rolling sequence for a second (even) stage with a flying shear stage.
Fig. 5 shows a modification of the rolling mill of the plant of the present invention.
6A to 6D show an example of using a welding machine installed upstream of the rolling mill.
Figure 7 shows a schematic view of a second embodiment of a plant according to the invention.
Figure 8 shows a schematic view of a double winding and unwinding strip system for discharging from a pickling line to enter the mill.
Fig. 9 shows the operation sequence of the above-described double winding and unwinding system.
In the drawings, like numerals identify like elements or components.

Referring to Figs. 1 to 9, a preferred embodiment of a combined continuous pickling and reversible cold rolling plant is shown.

The subject matter, plant of the present invention, in all embodiments:

A pickling line for continuously picking the strip;

- increased capacity storage means (20, 20 ') disposed downstream of the pickling line for storing pickled strips having a capacity of 500 meters to 3000 meters of strip length;

- a reversible cold rolling mill located downstream of said storage means (20, 20 ') and having at least two first rolling stands (19);

- downstream of the first rolling stand (19), winding the strip after the first rolling step or the odd rolling step, advantageously winding a coil having a weight of 100 to 300 tons and a diameter of up to 6 meters A reel 21 that is sized;

- a welder (2 ') arranged between the storage means (20, 20') and the first rolling stand (19);

At least one reel disposed upstream of the first rolling stand (19) and downstream of the welder (2 ') for winding at least a portion of the strip after a second rolling step or an even rolling step, (16), advantageously at least a predetermined weight or diameter limit of the coil, such as a specific gravity of, for example, 15 kg / mm to 21 kg / mm or a diameter of about 2000 mm to 2100 mm, One reel (16);

- disposed between said at least one second reel (16) and said first rolling stand (19) such that when a portion of the strip wound onto the reel (16) reaches said predetermined weight or diameter limit of the coil For example, shears 22, 23, which are configured to cut the rolled strip.

Advantageously, the welder 2 'is adapted to weld the head of the rolled strip discharged in the second rolling step obtained from the cutting performed by the first cutting means to the strip head coming out of the storage means 20, 20' .

The reel 21 has an increased capacity and is made of a thickened tube or metal round bar which can withstand a weight of up to 300 t weight or a large coil with a diameter of up to 6 meters. This reel 21 is also sized to apply a pull action of between 350 kN and 500 kN, preferably 400 kN during rolling to facilitate an increase in thickness reduction in the mill.

In a first embodiment of the invention, the welder 2 'is configured to cut a strip coming from the storage means 20 after a predetermined amount of strip has undergone the first rolling step, thereby separating the rolling mill from the pickling line. Referring to Figures 1 and 6d, the pickling lines are in order:

Characterized in that it comprises at least two unwind reel (1) and a welder (2), preferably a laser welder, for defining a continuous strip by making a rollable joint between the strips unwound by the reel Input section;

- input storage means (3) for storing said continuous strip and ensuring continuous operation of the pickling process;

A scale or oxide breaker 4 for crushing the oxide layer covering the continuous strip through a combined action of pulling and alternating bending against rollers of the appropriate diameter to promote continuous etching;

As the pickling tank 5, for example according to the required productivity from 2 to 4, the above-mentioned etching occurs on the continuous strip; The tank (5) comprises the pickling tank (5), which is provided with an auxiliary system for recirculating and heating the acid pickling solution.

Along the entire pickling line, a strip guide system, a pulling control system and various auxiliary systems are provided.

Optionally, downstream of the pickling tank 5:

- intermediate storage means (6) in which the pickled continuous strip discharged from the pickling tank (5) is stored after being rinsed and dried;

- a machine (7) for trimming the edge of the pickled continuous strip, said intermediate storage means (6) being adapted to prevent the trimming machine (7) from stopping in the pickling process when the trimming machine (7) The trimming machine 7, which performs the functions of the present invention, may be provided.

Advantageously, the plant of this first embodiment of the present invention provides an increased capacity storage means (20) directly downstream of the pickling tank (5) or trimming machine (7), acting as a storage means at the outlet of the pickling line , Which is sized to accommodate a pickled continuous strip of 500 to 3000 meters, preferably at least 2000 meters.

The increased capacity storage means 20 includes at least a movable carriage including at least three idler rollers at one end and an idler roller fixed at the opposite end to define a serpentine path of the picked continuous strip As shown in FIG. By movement, the moveable carriage can increase the stored strips. On the downstream side of the increased capacity storage means 20, in order:

- equipment (9) for controlling the pulling and centering of pickled continuous strips of a size such that a pulling action of between 250 kN and 500 kN, preferably of 400 kN, can be obtained;

- said welder (2 '), preferably a laser welder;

- at least one reel (16) configured to wind a portion of the strip having a specific gravity of 15 kg / mm to 21 kg / mm or a coil having a diameter of up to 2000 mm to 2100 mm;

Cutting shears 22 and 23;

- said at least two reversible first rolling stands (19) of four or six stages;

A reel 21 which is advantageously arranged to wind a coil having a weight of between 100 and 300 tons and a diameter of up to 6 meters can be provided.

In an advantageous variant, there are only two first rolling stands 19. Whereby two rolling steps are performed with a total thickness reduction of four times.

Along the mill, auxiliary systems for cooling and lubricating the strip and other auxiliary systems for monitoring the rolling process are provided.

The operation of this first embodiment of the present invention (Figs. 1 to 6D) is described below.

The unwind reel (1) of the input section unwinds each strip welded together by the welder (2) to define a continuous strip. In order to ensure continuous operation of the pickling process, the continuous strip is stored in the input storage means (3). Continuous strips still covered by the oxide layer exiting from the storage means 3 cross the scale crusher 4 and through the combined action of pulling and alternating bending for the roller of the appropriate diameter the oxide layer is pulverized Thereby promoting continuous etching in the pickling tank 5. Then, the continuous strip is rinsed and dried after passing through the pickling tank 5.

When provided, the pickled continuous strip enters the intermediate storage means 6 and then traverses the edge trimming machine 7.

The pickled continuous strip then enters the increased capacity storage means 20 and is stored in a serpentine path along with the idler rollers of the pickled continuous strip, for example as schematically shown in FIG.

The pickled continuous strips then pass through the equipment 9 controlling the pulling action and centering that define the input system to the mill and traverse the welder 2 '.

If a leading strip 40 of about 30 meters in length is provided on the take-up reel 21, advantageously the head 41 of the continuous strip picked up with the leading strip 40 by the welder 2 ' It is possible to provide the joining portion 26 between the two stand rollers 19 while the strip is pulled by the take-up reel 21 to obtain the possibility of feeding this joining portion 26 (Figs. 6A to 6C) 6d). The head 41 of the strip is prepared for welding by performing precise cutting using the welder 2 '. Before performing the welding, the end of the leading strip 40 is also prepared by performing precision cutting using the welder 2 'as well.

During the first (odd) rolling step, the first stand 19 is rotated about the axis of the reel 21 in order to realize a so-called mega coil, i.e. a coil with a weight of 100 to 300 tons and a diameter of up to 6 meters, , Continuously rolling at least four strips (with four welded joints, also taken together with the leading strip) welded together, belonging to the continuous strip described above. At this point, the welder 2 'cuts the joint that joins the fourth strip of the continuous strip described above to the fifth strip. As soon as the weight limit of 300 tons or the diameter limit of the coil of 6 meters is reached, the specific sensor sends a command signal to the welder 2 'which performs the above cut.

The number of welded start strips required to make the mega coil described above may vary based on the length of the start strip.

During this first rolling step, the increased capacity storage means 20, which has reached its maximum storage capacity at the beginning of rolling, is emptied due to the speed difference between the rolling mill and the pickling line.

The tail of the pickled continuous strip cut by the welder 2 'is fed onto the take-up reel 16 (Fig. 3a) to start a reversible second (even) rolling step of the strip wound onto the reel 21 do.

When the reel 16 winds the first rolled coil having a specific gravity of 15 kg / mm to 21 kg / mm or a diameter of 2000 mm to 2100 mm, the mill is stopped and a specific sensor is placed on the reel 16 The first rolled coil is unloaded from the reel 16 by sending a command signal to the static cutting shear 22 to be cut. The strip head obtained from this static cutting discharged from the first rolling stand 19 is fed onto a reel 16 and the second rolling step is carried out on a reel 16 having a specific gravity of 15 kg / mm to 21 kg / mm or a diameter of 2000 mm to 2100 mm Lt; RTI ID = 0.0 > 16). ≪ / RTI > The mill is stopped again and the static cutting shear 22 cuts the strip wound onto the reel 16 and the second rolled coil is unloaded from the reel 16. [ These operations are repeated until the second rolling stage of the final rolled coil, for example, the fourth coil, when the leading strip fixed to the reel 21 is about to enter the first rolling stand 19. When the rolling is stopped and the first rolling stand 19 is opened and the static cutting shear machine 22 cuts the strip again and the final rolling with a specific gravity of 15 kg / mm to 21 kg / mm or a diameter of 2000 mm to 2100 mm The head of the leading strip reaches the welder 2 'when the coil is unloaded from the reel 16 and can be rolled together with the head of the pickled continuous strip pre-cut by the welder 2' . When this welding is complete, the cycle resumes with the first (odd) rolling step and the formation of a new mega coil on the reel 21. By inserting the welder 2 'at the entrance of the mill and leaving the strip tail from the previous roll which can be welded to the head of the pickled continuous strip previously cut by the welder 2' A condition of continuous rolling is generated.

During the rolling step, the increased capacity storage means 20 is filled with a pickled continuous strip exiting the pickling line. Advantageously, the speed of the pickling line is adjusted to be substantially equal to the time of full filling of the storage means 20 with the cycle time of the mill to complete the formation of the above-described rolled coil on the reel 16. [

To obtain the conditions of continuous rolling in the second or even rolling stage, the variant may include a flying cutting shear 23 instead of the static cutting shear 22 and a double reel or reel 16 ) Carousel 24 (Fig. 4). The flying cutting shear machine 23 is configured to cut the rolled strip at a speed of 50 mpm to 500 mpm. The carousel 24 has two reels 16 which are generally hinged on a rotating drum, facing each other in a radial direction, which alternately winds the rolled strips: one of the reels winds the last coil , The other reel is free from the previously wound last coil.

In the second embodiment of the present invention shown in Figures 7 to 9, the increased capacity storage means 20 'comprises a coil (mega coil) having a weight of 100 to 300 tons and a diameter of up to 6 meters At least another increased capacity reel 28 of size. Advantageously, the mega coil is integrally formed at the end or opposite side of the rotating platform 27 (FIG. 8) configured to rotate 180 degrees relative to the vertical axis after a predetermined period of time at which the mega coil is wound on one of the two reels 28, 28 ' Two different incremental capacity reels 28 and 28 'are provided and thus alternatively a first reel 28 is used as a reel for winding pickled continuous strips exiting the pickling line and a second reel 28 ') Is used as a reel for unwinding pickled continuous strips fed to the mill. A second cutting means arranged upstream of the rotating platform 27 and configured to cut the picked strip when the mega coil is wound on one of the two reels 28, 28 ', for example another shearing machine (not shown) Is provided. In this case, too, the command signal is transmitted to the second cutting means when the specific sensor reaches the weight limit of 300 tons or the coil diameter limit of 6 meters. After this cutting, the rotating platform 27 is rotated by 180 °.

7) may be provided with an idler roller 8 'of pickled continuous strip upstream of the second cutting means, the purpose of which is to prevent the increased capacity take-up reel 28 And stores the strips processed by the pickling line every time it stops. The same components of the plant of FIG. 1, that is, all components denoted by reference numerals 1, 2, 3, 4, 5, 6 and 7 are provided upstream of the serpentine path 8.

The rotating platform 27, which defines a dual system for winding / unwinding the strip, can be operated, for example, by a rack system. The rotation is controlled by an electric or hydraulic motor 32 that allows rotation of 180 degrees to be achieved. On each of opposite sides of the rotating platform 27 is mounted a respective increased capacity reel 28, 28 'configured to take up / unwind a mega coil having a weight of 100 t to 300 t and a diameter of about 6 m.

The rotation commands 31, 30 and 31 ', 30' of each reel 28, 28 'are applied to the first rolling stand 19 of the reversible cold rolling mill by the winding rotation of the strip coming from the pickling line, Independent from each other so as to independently control the unwind rotation.

During the 180 ° rotation of the rotating platform 27, the rotation commands 31, 30 and 31 ', 30' are transmitted through respective movable joints 29, 29 'retracted to the respective reels 28, 28 '.

The strips wound onto and unwound from reels 28, 28 'are aligned by axial movement of respective mandrels 34, 34' controlled by corresponding hydraulic cylinders 33, 33 ' And is maintained at the center.

On the downstream side of the reels 28, 28 ', and thus downstream of the rotary platform 27,

A welder 2 ', preferably a laser welder;

At least one reel (16) configured to wind a portion of the strip having a specific gravity of 15 kg / mm to 21 kg / mm or a coil having a diameter of up to 2000 mm to 2100 mm;

A cutting shear (22);

- said at least two reversible first rolling stands (19) of four or six stages;

An increased capacity reel 21 is provided which is configured to wind a coil having a weight of preferably 100 to 300 tons and a diameter of up to 6 meters.

In an advantageous variant, there are only two first rolling stands 19. Whereby two rolling steps are performed with a total thickness reduction of four times.

Along the mill, an auxiliary system for cooling and lubricating the strip and an auxiliary system for monitoring the rolling process are provided.

The operation of this second embodiment of the present invention (Figs. 7 to 9) is described below.

The unwind reel (1) of the input section unwinds each strip welded together by the welder (2) to define a continuous strip. In order to ensure continuous operation of the pickling process, the continuous strip is stored in the input storage means (3). Continuous strips still covered by the oxide layer exiting from the storage means 3 cross the scale crusher 4 and through the combined action of pulling and alternating bending for the roller of the appropriate diameter the oxide layer is pulverized Thereby promoting continuous etching in the pickling tank 5. Then, the continuous strip is rinsed and dried after passing through the pickling tank 5.

When provided, the pickled continuous strip enters the intermediate storage means 6 and then traverses the edge trimming machine 7.

The pickled continuous strip then enters the increased capacity storage means 20 ', for example by winding onto an increased capacity reel 28' of the rotating platform 27 (FIG. 8).

Fig. 9 schematically shows the sequence of operations at the speed of the rotating platform 27. Fig. In the first step (FIG. 9A), toward the first rolling stand 19 to initiate the first rolling process, the first reel 28 begins to wind the mega coils of the pickled strip, while the second reel 28 28 ') begin to unwind other previously wound mega coils.

In the second step (FIG. 9B), while the reversing mill performs the second rolling step and the second reel 28 'is empty, the first reel 28 completes the winding of the mega coils of the pickled strip, The winding is stopped and the picked strip is cut off by the second cutting means upstream of the rotating platform 27 and the rotating platform 27 picks the first reel 28 toward the first rolling stand 19 And starts to rotate to bring it to the position to unwind the strip.

In the third step (Fig. 9c) with the first reel 28 in the unwinding position, the strip is unwound from the first reel 28 and moved to a supply or welding position close to the welder 2 ' The second reel 28 'begins to wind a new mega coil of the pickled strip.

The head of the strip unwinded from the new mega coil onto the reel 28 or reel 28 'is prepared by performing precision cutting with the welder 2' to prepare for continuous welding.

Assuming that it leaves a leading strip about 30 meters long on the take-up reel 21, it is desirable to make the weld between the head strip by the welder 2 'and the head of the picked strip coming from the first reel 28 So that the possibility of feeding the strip taught by the discharged reel 21 to this joint through the reversing mill with two first stands 19 is obtained.

The end of the leading strip is also prepared by performing precise cutting using the welder 2 'before performing the welding.

During the first (odd) rolling stage, the first stand 19 continuously rolls the unrolled strip from the first reel 28 to obtain a so-called mega coil on the increased capacity reel 21.

During this first rolling step, the mega coils on the increased capacity take-up reel 28 are completely unwound, while another reel 28 ', at the same time winding up the picked strip, winds the new mega coils.

The tail of the pickled continuous strip rolled and rewound onto reel 21 is fed onto take-up reel 16 to start a second reversal (even) rolling step (Fig. 7).

When the reel 16 winds the first rolled coil having a specific gravity of 15 kg / mm to 21 kg / mm or a diameter of 2000 mm to 2100 mm, the mill is stopped and a specific sensor is placed on the reel 16 The first rolled coil is unloaded from the reel 16 by sending a command signal to the static cutting shear 22 to be cut. The resulting strip head discharged from the first stand 19 is fed onto a reel 16 and the second rolling step is carried out on a reel 16 having a specific gravity of 15 kg / mm to 21 kg / mm or a diameter of 2000 mm to 2100 mm, And is resumed to obtain a rolled coil. The mill is stopped again and the static cutting shear 22 cuts the strip wound onto the reel 16 and the second rolled coil is unloaded from the reel 16. [ These operations are repeated until the second rolling stage of the final rolled coil, for example the fourth coil, when the leading strip is about to enter the first rolling stand 19. When the rolling is stopped and the first stand 19 is opened and the static cutting shear machine 22 again cuts the strip and the final rolled steel sheet 22 having a specific gravity of 15 kg / mm to 21 kg / mm or a diameter of 2000 mm to 2100 mm The coil is unloaded from the reel (16).

In the meantime, as soon as the winding of the mega coils is completed at the increased capacity of the take-up reel 28 ', the winding is stopped and the picked strip is cut off by the second cutting means upstream of the rotating platform 27, The rotating platform 27 is rotated 180 ° to bring the reel 28 'to a position for unwinding towards the reversing mill and to bring the reel 28 to a position for winding the strip coming from the pickling line.

The head of the strip unwinded from the new mega coil onto the reel 28 'is fed to reach the welder 2' in a known manner and is subjected to precision cutting with the welder 2 ' do. Before performing the welding, the end of the leading strip is also prepared by performing precision cutting using the same welder 2 '.

Once this welding between the head strip and the head of the strip of the new mega coil is completed, the cycle is resumed with the first (odd) rolling step and the continuous formation of the mega coils on the reel 21. The condition of continuous rolling is created in the first or the odd rolling step by inserting the welder 2 'into the inlet of the mill and leaving the strip tail from the previous mill which can be welded with the head of the continuous picked continuous strip.

To obtain the conditions of continuous rolling in the second or even rolling stage, a variant may also be used in place of the static cutting shear machine 22, in place of the single-reel 16, (In a manner analogous to that of Fig. 4). The flying cutting shear machine 23 is configured to cut the rolled strip at a speed of 50 mpm to 500 mpm. The carousel 24 has two reels 16 that are generally hinged on a rotating drum that are opposite to each other in a radial direction, which alternately winds the rolled strip: one of the reels winds the last coil , The other reel is free from the previously wound last coil.

It is possible to provide another rolling stand 25 which is disposed upstream of at least two first rolling stands 19 and which is configured to be opened in the odd rolling stage and closed in the even rolling stage. Thus, two rolling steps are performed with a total thickness reduction of 5 times. Advantageously, the other rolling stand 25 is provided with a working roll having a surface roughness greater than the surface roughness of the working rolls of the two first rolling stands 19. This variant makes it possible to obtain a roughly controlled rolling surface in the final rolling step. Preferably, the rolling stand 25 will be cooled in a second and final rolling step with a dedicated system to obtain better surface cleaning.

Claims (15)

As a combined pickling and rolling plant for pickling and rolling metal strips,
A pickling line for continuously pickling the strip;
Storage means (20, 20 ') arranged downstream of said pickling line for storing the pickled strip;
- a reversible cold rolling mill located downstream of said storage means (20, 20 ') and having at least two first rolling stands (19);
- a first reel (21) disposed downstream of said at least two first rolling stands (19) for winding said strip after a first rolling step;
- at least one second reel (16) disposed upstream of said at least two first rolling stands (19) for winding at least a portion of said strip after a second rolling step opposite to said first rolling step, , Said at least one second reel (16) being sized to take up a portion of the strip up to a predetermined weight or diameter limit of the coil;
- a strip portion disposed between said at least one second reel (16) and said at least two first rolling stands (19) such that the strip portion wound on said at least one second reel (16) And a first cutting means configured to cut the rolled strip every time a limit or diameter limit is reached, wherein:
The pickling line has a first welder (2) in the input section of the pickling line, the first welder (2) is for welding the strip to define a continuous strip,
The storage means (20, 20 ') for storing the pickled strip have a capacity of 500 to 3000 meters of strip length,
The first reel 21 is sized to take up a coil having a weight of 100 to 300 tons and / or a diameter of up to 6 meters,
A second welder (2 ') is arranged between said storage means (20, 20') and said at least two first rolling stands (19)
The at least one second reel (16) is disposed downstream of the second welder (2 '),
The second welder (2 ') is arranged so that the head of the rolled strip, which is obtained from the cutting performed by the first cutting means and discharged in the second rolling step, The head being configured to be welded to the head,
plant. The method according to claim 1,
The second welder (2 ') is configured to cut the strip coming from the storage means (20) after a predetermined amount of strip has undergone the first rolling step, separating the rolling mill from the pickling line
plant. The method according to claim 1,
Characterized in that said storage means (20 ') comprises at least one third reel (28) which is of a size that coils a coil having a weight of 100 to 300 tons and / or a diameter of up to 6 meters.
plant. The method of claim 3,
By providing two third reels 28, 28 'integrally at the opposite ends of the rotating platform 27 configured to rotate about a vertical axis, alternatively, a first third reel 28 may be withdrawn from the pickle line Is used as a reel for winding the strip, and the second third reel (28 ') is used as a reel for unwinding the strip supplied to the rolling mill,
plant. 5. The method of claim 4,
When a coil having a weight of 100 to 300 tons and / or a diameter of up to 6 meters is wound on one of the two third reels (28, 28 ') arranged upstream of the rotary platform (27) Wherein the second cutting means is configured to cut the strip,
plant. 6. The method according to any one of claims 1 to 5,
There is provided at least one other rolling stand (25) arranged upstream of said at least two first rolling stands (19) and configured to be opened in said first rolling stage and closed in said second rolling stage, (25) is provided with a work roll having a surface roughness larger than the surface roughness of the work rolls of the two first rolling stands (19)
plant. 6. The method according to any one of claims 1 to 5,
The first welder (2 ') is provided with a leading strip (40) fixed to the first reel (21) such that the leading strip (40) ≪ RTI ID = 0.0 > 41, < / RTI >
plant. 6. The method according to any one of claims 1 to 5,
The first cutting means is a static cutting shear machine (22) or a flying cutting shear machine (23)
plant. 9. The method of claim 8,
Wherein the carousel (24) of the double second reel (16) or the second reel (16) is provided to perform an even stage of continuous rolling in the case of a flying cutting shear stage. 10. A pickling and rolling process for pickling and rolling metal strips by a plant according to claim 1, wherein:
a) continuously pickling the strip by a pickling line;
b) storing said pickled strip by said storage means (20, 20 ') with a capacity of 500 to 3000 meters of strip length;
c) performing a first rolling step on a predetermined amount of strips in said at least two first rolling stands (19) and applying a coil having a weight of between 100 and 300 tons and / or a diameter of up to 6 meters Continuously winding onto a reel (21);
d) performing a second rolling step, in a direction opposite to said first rolling step, for said predetermined amount of strips in said at least two first rolling stands (19) to form a rolled strip, Winding a first portion of the strip rolled to a predetermined weight limit or diameter limit onto the at least one second reel (16) to form a first rolled coil;
e) cutting said rolled strip by said first cutting means after formation of said first rolled coil;
f) winding up another portion of the rolled strip onto the at least one second reel (16) to a predetermined weight limit or diameter limit of the coil to form another rolled coil and form each of the other rolled coils Cutting the rolled strip by the first cutting means;
g) the second rolled step of the head of the rolled strip, obtained from the final cutting performed by the first cutting means, by the second welder (2 ') to the storage means (20, 20' A step of welding a strip head coming out from the strip head; And
h) repeating steps b) to g) while continuing to carry out step a).
fair. 11. The method of claim 10,
Between step c) and step d), a cut of the pickled strip by the second welder (2 ') is provided to separate the mill from the pickling line,
fair. 12. The method of claim 11,
The speed of the pickling line is adjusted to equalize the time occupied by the storage means 20 and the cycle time of the rolling mill to complete the formation of the rolled coil on the at least one second reel 16 ,
fair. 11. The method of claim 10,
Characterized in that the coil with a weight of 100 to 300 tons and / or a diameter of up to 6 meters comprises a second means (20, 28 ') comprising two third reels (28, 28') integral with the opposite end of the rotary platform (27) ', A cut of the strip is provided upstream of the rotating platform 27,
fair. 14. The method of claim 13,
After the first coil having a weight of 100 to 300 tons and / or a diameter of up to 6 meters is wound onto one of the two reels 28, 28 ' The other reel 28 of the two third reels 28, 28 'can be made to have a second coil with a weight of 100 to 300 tons and / or a diameter of up to 6 meters , And the reel (28 ') is used as a reel for unwinding the first coil to supply the rolling mill or the like,
fair. 15. The method according to any one of claims 10 to 14,
A leading strip 40 secured on the first reel 21 is provided before the first rolling step and by the second welder 2 ' Creating a welded joint between the head (41) and the leading strip (40); And before said step g), said at least two rolling stands (19) are opened and said rolled strips obtained from the final cutting performed by said first cutting means, when said leading strip is about to enter the rolling mill Said head of said second welder being proximate said second welder,
fair.

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