DE102017202909A1 - Method and plant for producing a metallic strip - Google Patents

Abstract

The invention relates to a method for producing a metallic strip (1), wherein the strip (1) is rolled in a rolling mill (2), wherein the strip (1) adjoins a point downstream of the rolling mill (2) in the conveying direction (F) Biegestreckrichtprozess is subjected to bending in a straightener (3) and wherein the tape (1) at a downstream of the bending straightener (3) in the conveying direction (F) location on a reel (4) is reeled. In order to increase the degree of flatness of the belt, the invention provides that the belt (1) between the rolling mill (2) and the bending straightener (3) at least temporarily under a first tensile stress σ ₁ ) is held, that the band (1) in The conveying direction (F) behind the bending straightener (3) at least temporarily under a second tension (σ ₂ ) is maintained and that the band (1) in the region of the bending straightener (3) at least temporarily under a third tensile stress (σ ₃ ) is held the third tensile stress (σ ₃ ) is greater than the first tensile stress σ ₁ ) and the second tensile stress (σ ₂ ). Furthermore, the invention relates to a system for producing a metallic strip.

Description

The invention relates to a method for producing a metallic strip, wherein the strip is rolled in a rolling mill, wherein the strip is subjected to a bending straightening process in a bending straightener at a location downstream of the mill in the conveying direction and wherein the strip is at a location downstream of the bending straightener in the conveying direction is reeled on a reel. Furthermore, the invention relates to a system for producing a metallic strip.

The requirements for cold strip flatness in thin hot strip, for example sold directly, or in the hot strip flatness of hot strip, which are rolled and wound endlessly for a long time under tension and in which there are only insufficient flatness measurements, are constantly increasing.

To improve flatness, draft levelers have been proposed in the past that can be used behind hot strip mills. Such an application for endless rolling is for example in the GB 2 163 689 A disclosed. An arrangement of stretch leveling machines in front of a reel driver or between reel driver and reel disclose the DE 2 537 188 A1 , the US 4,316,376 A. , the EP 0 906 797 B1 , the DE 199 53 915 A1 , the EP 2 038 076 B1 and the EP 3 061 535 A1 , A stretch straightener immediately behind the hot strip mill will be in the US 4 539 830 A and within the cooling section in the DE 10 2013 214 344 A1 disclosed. Other solutions show the DE 10 2005 060 046 B4 and the EP 1 230 993 B1 ,

The previously known solutions according to the cited documents have various disadvantages.

The invention is therefore based on the object to provide a method and a system with which or with which it is possible to increase the degree of flatness of the belt.

The solution of this problem by the invention is characterized in that the strip is held at least temporarily under a first tensile stress between the rolling mill and the bending straightener, that the strip is held in the conveying direction behind the bending straightener at least temporarily under a second tension and that the band in the Area of the bending straightener is at least temporarily held under a third tensile stress, wherein the third tensile stress is greater than the first tensile stress and the second tensile stress.

The first tensile stress and the second tensile stress are preferably between 5 and 25 N / mm ² . The third tensile stress is preferably between 30 and 80 N / mm ² , more preferably between 40 and 60 N / mm ² . Excluded from said tension are the head and the end of the band. The train level on the transport route before the bending straightener section and the transport route after the bending straightener section may be different.

The mean tension level within the drafting straightener section is preferably determined as a function of the strip material, the strip temperature within the straightening section and the strip thickness, and is preferably set and controlled using a process model. The train level in the adjacent transport routes also defines a process model.

The train levels on the long transport route between the last active rolling mill and the first driver of the bending jig and the transport distance from the second driver of the bending jig and the reel driver or the reel is thus lower than the Zugniveau within the Biereckreckrichterstrecke. Accordingly, the trains are decoupled from the neighboring routes in the area of the bending straightener route.

The tension in the belt is preferably influenced, controlled or regulated by a first driver and a second driver, wherein the first driver is arranged downstream of the bending straightener in the conveying direction and the second driver in the conveying direction behind the bending straightener or the two drivers the extension of the bending straightener in the conveying direction limit (in the latter case, the two drivers are therefore part of the bending straightener). The different train levels are thus adjusted by the drivers in front of and behind the bending straightener. Instead of the second driver behind the Biegestreckrichter can also take over their task, a scissors driver or a reel driver. In this case, the increased third tensile stress is built up in the area of the bending straightener between the first driver and a reel driver. The distance a then applies between the first driver and the reel driver. The second driver is then opened or not installed. The second tension is then only between reel driver and reel. At least one further driver (eg a scissors driver) can additionally be arranged behind the second driver of the bending extensifier unit.

The strip is preferably subjected to cooling in a cooling section between the rolling mill and the bending straightener. Preferably, cooling in the conveying direction behind the bending straightener no longer takes place. The advantage of this kind the cooling of the belt is that in this way the cooling distance no longer affects the flatness of the belt.

The strip preferably has a temperature in its bending straightening process which is between 20 ° C and 750 ° C, more preferably between 200 ° C and 600 ° C.

With the method mentioned, it is particularly advantageous to produce a hot strip having a thickness of between 0.5 mm and 2.5 mm.

The plant for producing a metallic strip comprises a rolling mill for rolling the strip, a rolling mill downstream of the rolling mill in the conveying direction of the strip and at least one downstream of the bending straightener in the conveying direction and provides according to the invention that the bending straightener arranged in the conveying direction at the front first driver and a in the conveying direction arranged behind the second driver, wherein the two drivers limit the extension of the bending straightener and wherein the distance in the conveying direction between the first driver and the second driver is at most 20 m. Preferably, the distance is at most 5 m. This minimizes the cycle time through the bending straightener and the associated constriction of the band due to the train.

Between the rolling mill and the bending straightener, a cooling section is preferably arranged; behind the bending straightener preferably no cooling track follows.

The bending straightener has a number of rollers for introducing a bending moment into the belt, wherein the diameter of the rollers is preferably at least 50 mm, particularly preferably at least 100 mm.

The bending straightener section comprises a bending straightener consisting of a number of rollers (for example 5 rollers) and / or a back bending unit consisting of further rollers (for example 3 rollers).

The driver may be in the classic design of successive two roles or be designed with a staggered arrangement of the rollers to produce a wrap angle and optionally additional torque transmission.

In order for the strip not to be excessively cooled due to the draft tube roll cooling (which is particularly important in endless rolling), the drafting strip rolls preferably have internal cooling and / or are externally cooled with stripper plates to shield the water from the strip to allow the strip to cool Reel temperature is not adversely affected. The strip cooling in the bending straightener section is further taken into account and taken into account when determining the target strip temperature behind the cooling section, so that the desired coil temperature is generated.

The invention thus relates in particular to a hot bending stripper behind a hot strip mill.

The proposed solution thus provides an optimization of the Biegestreckrichteranordnung and the Zugverteilung ready, resulting in the consequence to an improved degree of planeness of the produced strip.

A good flatness improvement by means of a Biegestreckrichtprozesses results for given strip material at high strip tension, high strip temperatures and small bending radii of the strip, d. H. with small straightening roll diameters. Too small roll diameter are disadvantageous in terms of maintenance, service life or role wear. Too high a draft and / or too high strip temperatures will result in large width constrictions on the long stretch between the last mill stand of the hot strip mill and the reel. The width constriction due to strip tension is also dependent on the flatness state itself and thus difficult to determine. Furthermore, the cooling section also influences the flatness condition of the belt.

Taking into account these findings results in an optimal stretcher arrangement, which is characterized in particular by the above features.

• 1 schematisch in der Seitenansicht eine Anlage zur Herstellung eines Bandes und
• 2 den Verlauf der Zugspannung im Band über der Erstreckung in Längsrichtung der Anlage.

In the drawing, an embodiment of the invention is shown. Show it:

• 1 schematically in side view a plant for the production of a band and
• 2 the course of the tension in the band over the extension in the longitudinal direction of the plant.

In 1 is a plant for the production of a steel strip 1 shown, wherein from a rolling mill 2 only the last rolling stand is indicated, from which the band 1 in the conveying direction F in the direction of a reel 4 expires (example provided here are two reel 4 ). Between the rolling mill 2 and the reel 4 is a bending straightener 3 arranged in which the tape is directed by a bending straightening process.

The bending straightener 3 is from a first driver 5 and a second driver 6 in its extension in the conveying direction F limited, being between the two drivers 5 . 6 a distance a is present. The bending straightener 3 has a number of roles 8th on, for applying corresponding bending stress on the tape 1 are formed in a conventional manner.

A cooling section is provided 7 between the rolling mill 2 and the bending straightener 3 is arranged and with which the tape 1 can be cooled.

Furthermore, in 1 some components indicated for the implementation of the production process of the tape 1 relevant, namely a flatness measuring device 9 , a temperature measuring device 10 , a temperature measuring device 11 , a scissors 12 and a reel temperature measuring device 13 ,

The promotion of the band 1 between the rolling mill 2 and the reel 4 results from the interaction of the last mill stand of the rolling mill, the first and the second driver 5 . 6 and in the embodiment by a reel driver 14 , By appropriate regulation of said components and in particular the first and the second driver 5 . 6 the tension in the band can be influenced.

How this is done according to the invention results from the illustration according to FIG 2 where the course of the tension over the track s (in conveying direction F running) is shown.

It can be seen that between the rolling mill 2 and the bending straightener 3 first a first tension σ ₁ is present, which is preferably in a range between 5 and 25 N / mm ² .

Between the bending jig 3 and the reel 4 there is a second tension σ ₂ which is also preferably in a range between 5 and 25 N / mm ² . The two tension must be σ ₁ and σ ₂ not the same.

However, the tension is in the range of the bending straightener 3 at a higher level. The third tension present here σ ₃ is in a preferred range between 40 and 60 N / mm ² .

Advantageously, it is provided that the distance a is relatively short and preferably extends only over about 5 m. As a result, the throughput time is through the bending straightener 3 low, which also results in a slight constriction of the band due to the train.

To separate the bands, the scissors are used for continuous rolling 12 used. The tension σ ₂ is thus for a short period = 0. The driver 6 takes over the train share σ ₂ to the train σ ₃ to be able to keep upright in the bending stripper area.

The bending straightening process is thereby significantly improved. This applies in particular if the process is operated with further parameters, as explained above.

This is especially true with regard to the temperature control, which is preferably chosen so that the band 1 in the area of the bending jig 3 a temperature between 200 ° C and 600 ° C.

LIST OF REFERENCE NUMBERS

1

tape

2

rolling mill

3

Bending trek judge

4

reel

5

first driver

6

second driver

7

cooling section

8th

role

9

Flatness measuring device

10

Temperature measuring device

11

Temperature measuring device

12

scissors

13

Coiling temperature measuring device

14

coiler drive

σ ₁

first tension

σ ₂

second tension

σ ₃

third tension

a

distance

s

route

F

conveying direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• GB 2163689 A [0003]
• DE 2537188 A1 [0003]
• US 4316376 A [0003]
• EP 0906797 B1 [0003]
• DE 19953915 A1 [0003]
• EP 2038076 B1 [0003]
• EP 3061535 A1 [0003]
• US 4539830 A [0003]
• DE 102013214344 A1 [0003]
• DE 102005060046 B4 [0003]
• EP 1230993 B1 [0003]

Claims (16)

Method for producing a metal strip (1), wherein the strip (1) is rolled in a rolling mill (2), the strip (1) being subjected to a bending straightening process in a bending straightener at a point downstream of the rolling mill (2) in the conveying direction (F) (3) and wherein the strip (1) is reeled on a reel (4) downstream of the bending straightener (3) in the conveying direction (F), characterized in that the strip (1) is interposed between the rolling mill (2). and the bending straightener (3) at least temporarily under a first tensile stress σ ₁ ) is held, that the band (1) in the conveying direction (F) behind the bending straightener (3) at least temporarily under a second tension (σ ₂ ) is held and that the Band (1) in the region of the bending straightener (3) at least temporarily under a third tensile stress (σ ₃ ) is maintained, wherein the third tensile stress (σ ₃ ) is greater than the first tensile stress σ ₁ ) and the second tensile stress (σ ₂ ). Method according to Claim 1 , characterized in that the first tensile stress σ ₁ ) and the second tensile stress (σ ₂ ) are between 5 and 25 N / mm ² . Method according to Claim 1 or 2 , characterized in that the third tensile stress (σ ₃ ) is between 30 and 80 N / mm ² , preferably between 40 and 60 N / mm ² . Method according to one of Claims 1 to 3 , characterized in that the tension in the belt (1) is influenced, controlled or regulated by a first driver (5) and a second driver (6), the first driver (5) being arranged in the conveying direction (F) in front of the bending straightener (3 ) and the second driver (6) in the conveying direction (F) behind the bending straightener (3) is arranged or the two drivers (5, 6) limit the extension of the bending straightener (3) in the conveying direction (F). Method according to one of Claims 1 to 4 , characterized in that the tape (1) between the first driver (5) and the reel driver (14) is optionally temporarily held under the third tension (σ ₃ ). Method according to one of Claims 1 to 5 , characterized in that the strip (1) between the rolling mill (2) and the bending straightener (3) is subjected to a cooling in a cooling section (7). Method according to one of Claims 1 to 6 , characterized in that the strip (1) in its bending straightening process has a temperature which is between 20 ° C and 750 ° C, preferably between 200 ° C and 600 ° C. Method according to one of Claims 1 to 7 , characterized in that it produces a hot strip having a thickness between 0.5 mm and 2.5 mm. Method according to one of Claims 1 to 8th , characterized in that the different tension levels σ ₁ , σ ₂ , σ ₃ are given by a process model depending on thickness, temperature and strip material. Plant for producing a metallic strip (1), comprising a rolling mill (2) for rolling the strip (1), a bending stripper (3) downstream of the rolling mill (2) in the conveying direction (F) of the strip (1) and at least one bending straightener (3) in the conveying direction (F) downstream reel (4), characterized in that the bending straightener (3) in the conveying direction (F) arranged at the front first driver (5) and a downstream in the conveying direction (F) second driver (6) wherein the two drivers (5, 6) limit the extent of the bending straightener (3) and wherein the distance (a) in the conveying direction (F) between the first driver (5) and the second driver (6) is at most 20 m. Plant after Claim 10 , characterized in that the distance (a) is at most 5 m. Plant after Claim 10 or 11 , characterized in that the second driver (6) in the conveying direction (F) behind the bending straightener (3) is optionally a reel driver (14) or scissors driver. Plant according to one of the Claims 10 to 12 , characterized in that between the rolling mill (2) and the bending straightener (3) a cooling section (7) is arranged. Plant according to one of the Claims 10 to 13 , characterized in that the bending straightener (3) comprises a number of rollers (8) for introducing a bending moment into the band (1), wherein the diameter of the rollers (8) is at least 50 mm, preferably at least 100 mm. Plant according to one of the Claims 10 to 14 , characterized in that the bending straightener stretch consists of a bending straightener consisting of a number of rollers and / or a return bending unit with more than one further roller. Plant according to one of the Claims 10 to 15 , characterized in that the Biegestreckrichter (3) and / or the first driver (5) and / or the second driver (6) depending on the use or not use of the bending stripper unit pushed into the transport line or moved next to the transport line and can be replaced by a roller table.

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