WO2017036769A1

WO2017036769A1 - Installation based on the csp concept and method for operating such an installation

Info

Publication number: WO2017036769A1
Application number: PCT/EP2016/069220
Authority: WO
Inventors: Dieter Rosenthal; Christoph Klein
Original assignee: Sms Group Gmbh
Priority date: 2015-08-28
Filing date: 2016-08-12
Publication date: 2017-03-09
Also published as: EP3341142A1; TWI615210B; DE102015216512A1; EP3341142B1; TW201711766A

Abstract

The invention relates to an installation and a method for producing metal strips, preferably steel strips, of a thickness of 0.8 to 25 mm in batch mode or semi-continuous mode, comprising at least one casting machine (1) for casting thin slabs and a rolling device (5, 8) arranged downstream of the at least one casting machine (1) and comprising a number of rolling stands for rolling thin slabs into metal strips of a predetermined thickness, and also at least one coiling device (11) arranged downstream of the rolling device (5, 8), wherein a shear (6) and a furnace (3) are arranged between the at least one casting machine (1) and the rolling device (5, 8), wherein the rolling device has a device for changing the roll gap of at least one rolling stand during the rolling operation and there is a control device, which controls the installation in such a way that switching over from batch mode to semi-continuous mode or back takes place according to the grade of metal, preferably the grade of steel, and the desired thickness of the metal strip to be produced, and that the switching over from batch mode to semi-continuous mode can take place in the course of the rolling operation by the rolling device.

Description

Plant according to the CSP concept and method for operating such a plant

1. Field of the invention

The invention relates to a system and a method for producing

Metal bands, preferably steel bands, of a thickness of 0.8 to 3.0 mm, of pre-potted thin slabs with a thickness of 40 - 140 mm, in batch or semi-continuous operation. The invention further relates to a method for operating such a system.

For the production of thin strips of the type mentioned above with a thickness of 0.8 to 3.0 mm, preferably at a width of up to 2000 mm, preferably about 1880 mm (+/- 2%), for some time so-called CSP- ® plants used, which due to the compact plant concept a special

enable economical and environmentally friendly production of such thin strips with high productivity and excellent strip quality. The

Abbreviation CSP-® stands for "Compact Strip Production." In a CSP-® plant, the liquid steel is cast into thin slabs, which after a

Temperature compensation in a tunnel kiln without roughing rolled directly in the rolling mill to thin strip. Due to the direct connection between casting and rolling, a CSP ® system stands out due to its particularly low profile

Energy consumption - compared to conventional hot strip mills can save up to 40% energy. Since the CSP ® plant concept also manages without pre-rolling for pre-rolling the thin slab, the investment costs are also reduced. In addition, a hot strip produced on a CSP ® plant is characterized by a high quality, it has a uniform structure and homogeneous mechanical-physical properties over the entire strip length and width. The band geometry lies within the narrowest tolerances. In this field, the invention relates to a system which can be operated both in batch mode and in semi-continuous operation, in particular can be switched between these modes. As a so-called batch operation, the expert calls such a procedure of the system in which the emerging from the casting thin slab is shortened depending on the thickness and even before entering the downstream tunnel kiln to such a length that after leaving the rolling device in the downstream coiler a Coil can be wound with a predetermined length and a predetermined weight. In batch mode, exactly one coil is produced from each individual slab. As a so-called semi-continuous operation of the expert calls a driving style of such a system in which the thin slab is cut after leaving the casting machine so that a so-called Jumbobramme arises whose length usually corresponds to an integer multiple of a slab from the batch mode. From such a Jumbobramme, which after leaving the

Casting machine is also introduced into the tunnel kiln, is then in

downstream rolled a thin strip rolled, which is cut to length after leaving the rolling device to respective coil weights and lengths by means of a usually flying shears. Such systems are used to produce thin strips of different thicknesses and different steel grades from low-carbon steel to advanced-high-strength steel grades.

2. State of the art

Installations for the production of metallic thin strip from pre-cast

Thin slabs have long been known to the skilled person for many years. The same applies to the CSP ® system concept.

For example, EP 2 195 124 B1 describes a compact and flexible CSP® plant for continuous, semi-continuous and batch operation. The system described here is designed so that it can be operated in all three possible modes for such types of plant, usually for batching two parallel casting machines are provided in front of the rolling device and a pair of scissors between the caster and the rolling device is arranged to the

Start rolling operation regardless of the casting speed for the thin slab. For the semi-endless bed, in turn, an oven length is required which allows the generation of a jumbo, thus an oven length that is longer than a single slab from the batch mode. Finally, the endless operation of such a system necessarily requires the arrangement of a heating device, in particular an inductive heating device, in the region of the roller direction, frequently between the individual rolling stands or at least between groups of rolling stands.

In addition, WO 2011/141790 A2 describes a method and an installation for the production of flat rolled products, which also implements the CSP plant concept. Under certain conditions, switching between all three operating modes mentioned above will also be effected in this system.

In the known systems and the known method for operating such systems, there is the problem that the semi-endless Betheb only then

Application can come when the rolling mill on a predetermined

Operating temperature is heated, otherwise, especially in those

Rolling mills, in which the roll nips, if necessary provided with a bias, are completely closed in order, in the event of operational suspension of the respective rolling mills, under the influence of the rolling forces acting on the metal strip To be able to achieve the desired thin strip thicknesses at all, disturbances can occur. Not infrequently, the initiation of a semi-continuous operation, especially in higher-strength grades leads to disruption of the rolling operation, for example due to a not easily introducing the strip beginnings in the nip.

3. OBJECT OF THE INVENTION It was therefore an object of the invention to specify a system and a method for its operation, in which the problems described above in the operation of the CSP® system can be reliably avoided. This task will be in

according to the invention with a system comprising the features of claim 1, and a method comprising the features of claim 8, dissolved.

Advantageous embodiments of the invention are disclosed in the description and in the dependent claims.

4. Summary of the invention

According to the invention, the semi-continuous operation can be used when the rolling device is warm and a final thickness in the target area of the minimum final thickness has already been reached in advance in the batch mode. The first final thickness in the semi-continuous operation preferably corresponds to the final final thickness in batch mode, wherein by means of adjusting at least the roll gap of a roll stand, preferably a plurality of roll nips of the rolling stands of the rolling device, by means of so-called "flying-gauge-change" then the minimum Final thickness set and achieved in the thin strip. Preferably, the separation of the band takes place in coils with a behind the

Roller device arranged flying shears, which is arranged in front of the reel device, in particular the here commonly used underfloor reels.

In a further preferred embodiment of the invention, the

Band thickness changes during the rolling operation carried out so that the tape head and the tape end still within the market demanded

Thickness tolerances are.

The invention thus provides a method and a system with a correspondingly programmed control device, which enables the switching from batch mode to semi-continuous mode, in which a part of a pre-potted Jumbobramme, preferably at least half of the Jumbobramme, with the minimum end thickness can be produced without the need to bring the hot strip to operating temperature under the action of external energy; Rather, the setting of the operating temperature of the system according to the invention, in particular of their rolling, in batch mode or in semi-continuous operation during the production of metal strips by selecting the correct rolling speed.

The inventive system and method of the invention thus allow using known system components and

accordingly controllable means with a lowest possible

Energy consumption, the production of thin strips in the most energetically favorable operating mode.

The system of the invention is thus able to produce thin strips of a variety of steel grades both in batch mode and semi-continuous operation and this produce particularly low thicknesses energetically favorable. Depending on the quality of the steel and the final product, the operating mode Batch mode is in principle for larger end thicknesses and the mode Semi-continuous mode for thinner or thinnest Thicknesses selected, the plant has a total capacity of about 4 million.

Annual tons in two-string operation, thus using two parallel casters, can provide. In a preferred embodiment of the invention, the rolling device has two groups of a plurality of rolling stands, in particular a first group with two rolling stands and a second group arranged downstream of the first group with up to five rolling stands. Between these groups of rolling stands, an induction heating can be arranged, which preferably consists of the

Rolling device and the entire rolling line is provided extendable. While induction heating is not used regularly in batch mode, induction heating can be used in semi-continuous operation, in particular in the case of induction heating

Production of thin and thinnest end thickness of the metal strip through the

Rolling device, used to keep the structure of the hot strip throughout the rolling process in the austenitic phase region.

Switching from batch mode to semi-continuous mode is done in a further preferred embodiment of the invention during the rolling process, thus when the strip is engaged with one or more stands of the rolling mill

Roller device stands. The switching is preferably carried out after rolling a plurality, preferably of more than two, more preferably of between two to two and a half, individual slabs. Thus, when the cast for semi-continuous operation and cut from the arranged behind the caster scissors jumbobrams a standard size of z. B. has five individual slab lengths, produces at least half of the coils produced from the Jumbobramme in the desired minimum final thickness in semi-continuous operation.

For processing the rolled thin strips is preferred if behind the last roll stand and before the reel device a preferably flying scissors is arranged, with which the thin strip produced can be cut to the desired length for the coil. Preferably, the length of the furnace between the casting machine and the

Rolling device dimensioned so that it corresponds to at least the length of a jumbo booms for performing the semi-endless operation. Usually, the length of a jumbobramme will correspond to a multiple of the length of a single slab, the length of the furnace, preferably of the tunnel kiln, being dimensioned such that a jumbobramme of five times the length of a long single slab

(Single slab with a maximum thickness of 40 mm) can absorb. Usual lengths of such tunnel kilns are about 250 m. The process according to the invention is preferably carried out on a plant according to the invention, as has already been discussed in detail above. The effects which can be achieved by the process according to the invention correspond to those which can be achieved with the system according to the invention. In the process according to the invention, thin slabs are preferably rolled to form thin strips, which are provided by the casting machine or in parallel

Leave casting machines with a thickness of 40 to 140 mm. This provides a process that provides the greatest possible mix of products, both in terms of final thickness achievable and steel grades to be processed.

Preferably, when the plant manufactures steel strip of the grade "low carbon steel", preferably steel strip with a thickness of 0.8 to 1, 2 mm in semi-continuous operation and steel strip with a thickness greater than 1, 2 mm in batch mode ,

Also preferred is a method in which the plant manufactures steel strip grade "medium-carbon steel", preferably steel strip with a thickness of 1, 4 to 1, 8 mm in semi-continuous operation and steel strip with thickness greater than 1, 8 mm in batch mode. Also preferred is a process in which the plant manufactures steel strip of the grade "high carbon steel", preferably steel strip with a thickness of 1, 4 to 2.0 mm in semi-continuous operation and steel strip with thicknesses greater than 2.0 mm Also preferred is a process in which the plant manufactures steel strip of the "high-strength low-alloyed steel" grade, preferably steel strip with a thickness of 1.4 to 2.0 mm in semi-continuous operation and with thicknesses greater than 2.0 mm in batch mode.

Also preferred is a method in which the plant manufactures steel strip of the quality "advanced high-strength steel", preferably with a thickness of 1, 4 mm 2.5 mm in semi-continuous operation and with thicknesses greater than 2.5 mm im batch operation.

5. Brief description of the figures

The invention will be briefly explained below with reference to two figures, which figures represent preferred embodiments of preferred effects of the invention without thereby limiting the scope of protection of the invention as defined in the appended claims.

In the figures show:

Figure 1 is a schematic representation of a CSP ® plant according to the invention, and

Figure 2 is a tabular listing of the producible strip thicknesses and

Machinable steel grades, broken down according to the respective

Operating mode of the system according to the invention. 6. Detailed description of the figures

Figure 1 shows a schematic representation of a CSP ® plant according to the invention, which is able to cast over the casting machine into thin slabs

To process steel grades both in batch mode and semi-continuous operation to make thin strips with a desired final thickness. Behind the two parallel casting machines 1, which feed the plant at least in batch mode, scissors 2 for dividing the thin slabs before entering the thin slabs in the or the roller hearth furnaces 3 are provided. These roller hearth furnaces or tunnel kilns 3 are used both for reheating and the same

Thin slab temperature. At least the length of the upper tunnel kiln 3 is dimensioned such that at least one jumbobramme for carrying out a semi-continuous operation can be completely accommodated in the tunnel kiln 3. The lower tunnel kiln 3 immediately downstream of the parallel casting machine 1 may also have this length, but must be at least equal to the length of a single slab for batch operation to be able to receive and heat this single slab when performing the batch operation. The second tunnel kiln 3 can also serve as a buffer for the upper casting machine tunnel kiln arrangement 1, 3 via a suitable switching device between the tunnel kilns 3.

Downstream of the upper tunnel kiln 3 and in front of the first roll stand group 5, a scale scrubber 4 for removing surface scale is provided, thereby positively promoting rolling in the first group of rolling stands 5

in particular, free from scale-related surface damage. Downstream of the first roll stand group 5 is a pair of scissors 6 for scooping the strip heads and strip ends of the roll stand 5 pre-rolled in the roll stand group 5

Intermediate belt arranged, thereby facilitating the threading of the belt within the second roll stand group 8. In addition, the cutting shears 6 serve to the rolling process within the first roll stand group 5 from

Separate rolling in the second roll stand group 8, in particular with regard to the entry speed of the intermediate belt in the second roll stand group 8 after exiting the first roll stand group 5. Between the first

Roll stand group 5 and the second roll stand group 8 is also a Induction heating 7 is arranged, which can preferably be removed from the rolling line, if the induction heater 7 is not required for carrying out the rolling process. This is regularly the case when the system according to the invention is run in batch mode, or when in semi-continuous operation bands with comparatively large thicknesses of 2 to 2.5 mm are to be produced. Downstream of the second roll stand group 8, a laminar cooling section 9 is arranged for setting the desired reeling temperature for the thin strip. This laminar cooling section 9 is preferably provided with means for controllably increased cooling of the thin strip, usually liquid nozzles or nozzles capable of applying a mixture of air and a cooling liquid to the thin strip. Between the laminar cooling section 9 and two separately controllable underfloor reels 1 1, a high-speed shear 10 is arranged for separating the finished rolled thin strip on the respectively desired Coillängen. FIG. 2 shows, by way of example, a tabular listing of the steel grades that can be machined on the system according to the invention and in the method according to the invention and the strip thicknesses to be produced via the system, wherein it is also indicated which steel grades and which strip thicknesses in the semi-endless-roll mode and the batch mode operating mode can be produced. In principle, "low-carbon steel" steel grades with final thicknesses greater than 1.4 mm can be used in batch mode and in the

Thickness range 0.8 mm to 1, 4 mm are produced in semi-continuous operation. The steel grade "advanced high-strength steel" is again produced in the thickness range 1, 4 to 2.5 mm in semi-continuous operation.

LIST OF REFERENCE NUMBERS

1 casting machine

2 scissors

3 tunnel kiln

4 scale washer

5 rolling stand group

6 cutting shears

7 induction heating

8 rolling stand group

9 laminar cooling section

10 high-speed scissors

1 1 underfloor reels

Claims

claims

Plant for the production of metal strips, preferably steel strips, in a thickness of 0.8 to 3.0 mm in batch or semi-continuous operation and

Thicknesses greater than 2.5 mm in batch mode, comprising at least one

Casting machine for casting thin slabs and a rolling mill arranged downstream of the at least one casting machine for rolling the thin slabs to metal strips of predetermined thickness, and at least one arranged downstream of the rolling device, wherein a scissors and a furnace between the at least one casting machine and the rolling device characterized in that the rolling means comprises means for changing the roll gap of at least one rolling stand during the rolling process and a control means is provided which controls the plant so that a

Switching from batch mode to semi-continuous mode or back depending on the grade of metal, preferably steel grade, and the desired one

Thickness of the metal strip to be produced takes place, and that the switching from batch mode to semi-continuous mode can take place during the rolling process by the rolling device.

Installation according to claim 1, characterized in that the rolling device comprises two groups of a plurality of rolling stands, preferably a first group with two rolling stands and a downstream of the first group arranged second group with up to six rolling stands.

Installation according to claim 2, characterized in that between the groups of rolling stands a preferably out of the rolling means extendable induction heating is arranged. Installation according to one of the preceding claims, characterized

characterized in that the switching from batch operation to semi-continuous operation in the course of the rolling process after rolling a plurality, preferably more than two, more preferably between between 2 and 5 individual slabs, can take place.

Installation according to one of the preceding claims, characterized

characterized in that behind the last rolling mill and before the

Reel a preferably flying scissors is arranged.

Installation according to one of the preceding claims, characterized

in that the length of the furnace, preferably of a tunnel kiln, is designed to correspond at least to the length of a jumbobramme for performing the semi-continuous operation.

Installation according to one of the preceding claims, characterized

characterized in that it is constructed according to the CSP plant concept.

Method for operating a system, preferably according to one of

Claims 1 to 7, for the production of metal strips, preferably

Steel strips, of a thickness of 0.8 to 3.0 mm in batch or semi-continuous operation and thicknesses greater than 2.5 mm in batch mode, comprising at least one casting machine for casting thin slabs and a downstream of the at least one casting machine arranged Rolling device having a plurality of rolling stands for rolling the thin slabs to metal strips of predetermined thickness, as well as at least one arranged downstream of the rolling device reeling device, wherein between the at least one

Casting machine and the rolling device, a pair of scissors and a furnace are arranged, characterized in that the roll gap of at least one roll stand is changed during the rolling process and a control device controls the plant so that a switchover from batch operation to semi-continuous operation or back depends on the metal grade, preferably steel grade, and the desired thickness of the metal strip to be produced, and that switching from

Batch operation for semi-continuous operation in the course of the rolling process by the rolling device takes place.

A method according to claim 8, characterized in that the switching from batch mode to semi-continuous operation in the course of the rolling process after rolling a plurality, preferably more than two, more preferably between 2 and 5 individual slabs takes place.

A method according to claim 9, characterized in that the switching from batch mode to semi-continuous operation in the course of the rolling process then takes place when the rolling device, in particular the work rolls of the respective rolling stands, in the batch mode, a predetermined

Operating temperature has assumed.

Method according to one of claims 8 to 10, characterized in that the thin slabs after leaving the at least one casting machine have a thickness of 40 to 140 mm.

A method according to any one of claims 8 to 11, characterized in that the change of the at least one nip during the rolling process is such that both the band end of the previously rolled metal strip and the tape head of the subsequent metal strip are within the required thickness tolerances.

Method according to one of claims 8 to 12, characterized in that the plant manufactures steel strip of the quality low-carbon steel, preferably steel strip with a thickness of 0.8 to 1, 2 mm in semi-continuous operation and with thicknesses greater than 1, 4 mm in batch mode.

14. The method according to any one of claims 8 to 12, characterized in that the plant produces steel strip of quality medium-carbon steel, preferably steel strip with a thickness of 1, 4 to 1, 8 mm in semi-continuous operation and greater in thickness 2.0 mm in batch mode.

15. The method according to any one of claims 8 to 12, characterized in that the plant produces steel strip of the quality high-carbon steel, preferably steel strip with a thickness of 1, 4 to 2.0 mm in semi-continuous operation and with thicknesses greater 2.5 mm in batch mode.

16. The method according to any one of claims 8 to 12, characterized in that the plant produces steel strip of the quality high-strength low-alloyed steel, preferably steel strip with a thickness of 1, 4 to 2.0 mm in semi-continuous operation and with thicknesses greater than 2.5 mm in batch mode.

17. The method according to any one of claims 8 to 12, characterized in that the plant produces steel strip of grade advanced high-strength steel with a thickness of 1, 4 to 2.5 mm, preferably in semi-continuous operation.

18. The method according to any one of claims 8 to 17, characterized in that the production of metal strips in batch mode without inductive heating of the strip and in semi-continuous operation only in the production of high-strength grades with small thicknesses, preferably high-strength low- alloyed steel with a thickness of 1, 4 to 1, 6 mm or advanced high strength steel with a thickness of 1, 4 to 1, 8 mm, carried out with inductive heating.

19. The method according to any one of claims 8 to 18, characterized in that the rolling device is fed in batch mode from two casting machines.