EP3558563A1

EP3558563A1 - Method for endless production of a coiled hot strip in a casting-rolling integrated plant, method for starting a casting-rolling integrated plant, and casting-rolling integrated plant

Info

Publication number: EP3558563A1
Application number: EP17826509.6A
Authority: EP
Inventors: Bernd Linzer; Roman Winkler
Original assignee: Primetals Technologies Austria GmbH
Current assignee: Primetals Technologies Austria GmbH
Priority date: 2016-12-22
Filing date: 2017-12-21
Publication date: 2019-10-30
Also published as: RU2019121897A3; CN110087801A; CN110087801B; RU2750305C2; EP3338914A1; RU2019121897A; WO2018115324A1

Abstract

The invention relates to a method for endless production of a coiled hot strip (15) in a casting-rolling integrated plant. The problem to be solved is that of specifying a method by which high-quality hot strip (15) of varying steel qualities can be cost-effectively produced. The method should also be reliable and cause extremely low operating costs. Said problem is solved by a method according to claim 1.

Description

description

Method for continuous production of a coiled hot strip in a cast-rolled composite plant, method for starting up a cast-rolled composite plant and cast-rolled composite plant

Technical Field The present invention relates to the technical field of cast-rolling compound plants. These are plants in a continuous casting plant for the continuous production of a steel strand with a slab format, e.g. Thin or

Middle slabs, directly and inline with a rolling mill for hot rolling a hot strip is connected. The hot strip is cooled after the rolling train in a cooling section and then discharged, e.g. by winding the tape into coils (English, coils). In the literature these installations are e.g. also known as TSCR (Thin Slab Casting and Rolling) or Arvedi ESP equipment.

In particular, the invention relates to endlessly operated cast-rolled composite plants in which the casting plant as a

Thin slab continuous casting machine is formed (English TSER Thin S_lab Endless Rolling). In the process, the continuously produced in the continuous slab caster is endless

Thin slab strand direct, inline and uncut

Walzstraße fed and rolled there to an endless hot strip. The strip is cooled after the rolling mill again in a cooling section, then the first time to a

cut certain length or a certain weight and wound into coils.

State of the art

Although an Arvedi ESP system is already much more compact than a CSP or a QSP system with a tunnel kiln, as well as operating costs and CO ₂ output per ton As hot-rolled strip has also been greatly reduced, there is a need for even more compact cast-and-strip composite plants for producing one-year hot-rolled strip production in the range of 1 million tons and less.

The solutions currently on the market, such as a continuous casting line with a downstream broadband line, an Arvedi ESP, Danieli QSP-DUE or SMS CSP / CEM system, are not compact enough for these low volumes and / or due to much higher annual production volumes of about 2.5 million tonnes and the high capital investment CAPEX with an annual production volume of about 1 million tons and less not economically operable. Thus, especially for small steel mills, there is a need for a compact cast-and-roll composite plant that is inexpensive to purchase and operate, yet capable of producing high quality hot strip of various grades of steel.

Two-roll strip casters with a downstream rolling mill are also known from the prior art. Although a two-roll strip caster is very compact and produces a strip immediately, this technology has not been able to prevail until now, since in particular medium to higher alloyed steel grades can not be reliably produced.

From DE 10 2007 022 932 AI a cast-rolling composite plant for producing a steel strip is known, in which between the continuous casting machine and the hot rolling mill, a milling machine 4 for milling a thin slab strand 3 is arranged. The mass flow of the continuous casting machine can be between 0.28 and 0.39 m ² / min. Since the thin slab or the pre-strip is (intermediate) heated before the finish rolling, the hot rolling does not take place exclusively from the casting heat.

WO 2007/054237 Al also discloses a cast-rolled composite installation for producing a steel strip. Of the Mass flow of the system can be 0.441 m ² / min. Since the pre-strip is preheated before the finish rolling, the hot rolling does not take place exclusively from the casting heat.

From WO 97/36699 a concept for the continuous operation of a cast-rolled composite plant is known. Here is the

Homogenized temperature of a thin slab strand produced in a continuous casting in a compensation furnace, the Dünnbrammenstrang then descaled, in a

Rolled, cooled and seven-stand rolling mill

wound. The document indicates that, starting from a specific throughput h ₀ * v _c of h ₀ * v _c > 0.487 m ² / min, the hot strip can be finish-rolled from the casting heat of the thin slab strand in the austenitic state. However, especially in the case of relatively thin thin slab strands, this concept requires very high casting speeds, eg, with a slab thickness of 50 mm, a casting speed of about 10 m / min. In the

industrial practice has been found that

Casting speeds v _c > 6 m / min are problematic because the reliability of the continuous casting machine decreases significantly. Attempting to achieve the specified specific throughput by using relatively thick slabs, for example, with a slab thickness of 100 mm by a casting speed of about 5 m / min, this leads to reliable conditions in the continuous casting, but the mill has many scaffolding (high CAPEX) to produce a hot strip with a thickness <10 mm can. In the practical

Application has also been found that the

Pre-rolled Vorband typically has to be reheated after 3 or 4 rolling passes. Thus, today's cast-and-roll compound plants are usually operated at a casting speed of 5, 6 or 7 m / min and the pre-strip is reheated in an induction furnace. Due to the

Intermediate heating but increase the operating costs (OPEX). Accordingly, there is a need for a low-cost and easy cast-and-cogeneration unit (low CAPEX) that can be reliably operated on the one hand and does not require intermediate heating (low OPEX) on the other hand high-quality hot strip with a thickness of 2.5 to 10 mm in the austenitic state can finish rolling.

How this problem can be solved is not apparent from the prior art.

Summary of the invention

The object of the invention is to overcome the disadvantages of the prior art and to provide a method for the endless production of a hot strip of steel in a cast-roll compound plant and a compact, favorable cast-rolling compound of the type mentioned, with which high quality hot strip of various

Steel grades (low-, medium- and high-carbon, but also HSLA, API grades, etc.) can be produced inexpensively. The process should be extremely reliable and cause extremely low operating costs. The cast-rolled compound plant according to the invention should be significantly cheaper than comparable ESP / QSP / CSP plants. In addition, a simple

Method for starting up a cast-rolled composite plant

specified so that the system can be approached quickly and reliably. This task is through a process of endless

Production of a coiled hot strip of steel in a cast-rolled composite plant according to claim 1. Advantageous embodiments are the subject of the dependent claims. Specifically, the solution of the object according to the invention is achieved by a process for the endless production of a

wound steel hot strip in a cast-rolling composite plant, wherein the cast-rolling composite plant a

Continuous casting plant for producing an endless

Thin slab strand, a rolling mill with several rolling stands for hot rolling of the thin slab strand to the hot strip, a cooling section for cooling the hot strip, a pair of scissors for Cross-cutting the hot strip and a winding device for winding the hot strip, comprising the steps:

- Continuous casting of a molten steel in one

Continuous casting mold of the continuous casting plant to the

Thin slab strand, wherein the thin slab strand at the exit from the continuous casting mold has a liquid core, a thickness of 45 to 70 mm, preferably 55 to 65 mm, and a width of 900 to 2300 mm, preferably 1100 to 1900 mm;

- Supporting, guiding and reducing the thickness of the

Thin slab strand in a strand guide the

Continuous casting plant, wherein the reduced thickness

Thin slab strand has a thickness h of 35 to 52 mm, preferably 40 to 50 mm, a casting speed v _c and a specific throughput D = hv _c of 0.45 m ² / min>D> 0.27 m ² / min;

- Hot rolling of the endless, reduced thickness

Thin slab strand in the rolling mill, wherein the

Thin slab strand exclusively from its casting heat out by at least three, preferably by three to five,

most preferably by four, rolling passes is rolled to the hot strip with a thickness of 2.5 to 10 mm and the last roll pass is made in the austenitic temperature range of the steel;

- cooling the hot strip in the cooling section;

- cutting the cooled hot strip; and

- winding the hot strip into coils in the

Winding device.

The aforementioned continuous casting mold is designed either straight or arcuate. However, a straight-through mold is preferred because impurities in the molten steel can be taken up by the casting powder and thus the internal quality of the thin slab strand is improved.

In the Durchlaufkokille a thin slab strand is formed with a liquid core, which at the exit from the

Continuous casting mold has a thickness of 45 to 70 mm, preferably 55 to 65 mm, and a width of 900 to 2300 mm, preferably 1100 to 1900 mm. The thin slab strand is in the the continuous casting mold subsequent strand guide supported, guided and reduced in thickness, so that the thickness-reduced thin slab strand has a thickness h of 35 to 52 mm, preferably 40 to 50 mm and a specific throughput D = hv _c of

0.45 m ² / min>D> 0.27 m ² / min. Thickness reduction can be advantageous in the case of liquid (so-called liquid core redcution) or partially liquid core (so-called soft core redcution) of the

Thin slab strand done. It is noteworthy in the method according to the invention for the continuous production of a wound hot strip that - as stated in the prior art - the highest possible throughput through the

Continuous casting is advantageous, but a mean specific throughput D between 0.27 and 0.45 m ² / min is sought. This will ensure that the

Continuous casting plant works reliably. The endless one

Thin slab strand is reduced in thickness after reduction without being previously descaled or heated, i. exclusively from its casting heat, in the rolling mill through

rolled at least three, more preferably by four, rolling passes to the hot strip with a thickness of 2.5 to 10 mm, wherein the last rolling pass takes place in the austenitic temperature range of the steel. Thus, the hot strip on an austenitic structure. Subsequently, the hot strip is cooled in the cooling section, transversely divided by the scissors and in the

Winding device wound into coils.

So that the energy content of the thickness-reduced thin slab strand can be set as accurately as possible, it is advantageous if a control or regulating device of the continuous casting by means of a mathematical model

Actual position of a sump tip along the transport path of the thin slab strand in the strand guide and an actual temperature profile along the transport path of the

Thin slab strand in the strand guide and preferably in normal planes to continuously calculated and the

Thin slab strand is continuously cooled, taking into account a target position of the sump tip in the strand guide, regulated, so that the actual position of the sump tip of the Target position corresponds as possible. Here it is

advantageous if the actual position of the sump tip lies in the last third of the arcuate region of the strand guide or in the horizontal outlet region of the strand guide.

The temperature of the hot strip at the last pass can be accurately adjusted when the actual temperature Ti _{actual of} the hot strip after the last pass in the rolling line and before cooling in the cooling section is measured and the cooling of the thin slab strand in the strand guide and / or the casting speed v _{c is} set regulated, so that the actual temperature Ti _Ist a setpoint temperature ison as possible corresponds. The coiling temperature of the hot strip can be set exactly when the actual temperature T ₂ i _s t of the endless hot strip is measured after cooling in the cooling section and

Cooling nozzles of the cooling section are controlled temperature-controlled, so that the actual temperature T ₂ i _s t a setpoint temperature T ₂ soii corresponds as possible.

To reduce the thickness of the hot strip and its

To improve surface quality, it is favorable if a bunch is then pickled and through several rolling passes in a cold rolling mill to a thickness of 0.3 to 7 mm

cold rolled.

When starting the cast roll mill, the one

Continuous casting plant for producing an endless

Thin slab strand, a rolling mill having a plurality of rolling stands for hot rolling the thin slab strand to the hot strip, a cooling section for cooling the hot strip, a scissors for cutting the hot strip and a winding device for winding the hot strip, the following steps are carried out:

- Casting the continuous casting, wherein a cold strand, which is a continuous casting mold of the continuous casting fluid-tight seals, is pulled out in the transport direction from the continuous mold;

Supporting and guiding a thin slab strand following the cold strand in a strand guide of the

continuous casting;

Passing the rolling mills of the rolling train, the cold strand passing the rolling train without being rolled;

- Optional cooling of the non-rolled thin slab strand in the cooling section;

- Cutting the dummy strand by the scissors;

- Feeding the cold strand, the cold strand preferably passes through the winding device and in

Transport direction is stored behind the winding device;

- dividing the non-rolled thin slab strand into a shredded material by the scissors and conveying out the shredded material;

- optionally increasing a casting speed and

Thickness reduction of the thin slab strand in the strand guide;

- Setting the rolling stands to the thin slab strand and hot rolling the thin slab strand into a hot strip;

- cooling the hot strip in the cooling section;

- cutting the cooled hot strip; and

- winding the hot strip into coils in the

Winding device. Initially, the cold strand is either in the transport direction

(English, top feeding) or contrary to the transport direction of the thin slab strand (English, bottom feeding) in the

Passed through mold, so that he the mold

fluid-tight seals. By casting the continuous casting plant, a thin slab strand is formed in the continuous casting mold, which is welded to the head of the cold strand. The cold strand including the subsequent thin slab strand is then pulled out of the mold and in the

Strand guide supported and guided. In order to prevent damage to the rolling stands by the cold strand or the relatively cold thin slab strand, the rolling stands against the setting for rolling a hot strip with a thickness between 2.5 and 10 mm are driven up, so that the Kaltstrang the rolling mill can happen unrolled.

Otherwise, it is of course also possible that the rolling stands are started up before starting.

Thereafter, the dummy strand of the following

Thin slab strand cut off by the scissors and discharged the cold strand from the roller table between the scissors and the winding device or the winding devices. This can be done particularly simply by the fact that the

Cold strand is accelerated by powered roller table rollers and stored in the transport direction behind the winding device on the roller table. At least the unrolled thin slab strand is then by the scissors in a

Chopped shredded material and the shredded material discharged. The conveying out can take place in that the shredded material is introduced into a scrap bucket below the roller table. Subsequently, it is advantageous if the casting speed of the continuous casting plant is increased stepwise, in particular to a specific throughput D with D = hv _c of

0.45 m ² / min>D> 0.27 m ² / min, and the thin slab strand in the strand guide of the continuous casting by hydraulic to the

Strand engageable strand guide rollers is reduced in thickness. Finally, the rolling stands are set to the thin slab strand, so that the thin slab strand is rolled into a hot strip, the hot strip is then cooled, transversely divided and wound up.

It is clear to the person skilled in the art that the transport direction in the continuous casting plant changes from the vertical direction via an arcuate section into the horizontal and follows the flow of material through the installation.

A simple, extremely compact and inexpensive cast-rolled composite plant for the production of a hot strip made of steel has:

a continuous casting machine, which is a continuous casting mold for the continuous production of a thin slab strand, which at the exit from the continuous casting mold a liquid core, a thickness of 45 to 70 mm and a width of 900 to 2300 mm, and a strand guide for supporting, guiding and reducing the thickness of the thin slab strand with a

Secondary cooling for cooling the thin slab strand, wherein the thin slab strand after the thickness reduction, a thickness of 35 to 52 mm, preferably 40 to 50 mm, a

Casting speed v _c and a specific throughput

0.45 m ² / min>D> 0.27 m ² / min;

a rolling line for hot rolling the reduced thickness thin slab strand, the immediately after

Rolling mill arranged at a continuous casting plant has at least three, preferably three to five, more preferably exactly four, rolling stands, wherein the hot rolling of the

Thin slab strand exclusively from its casting heat out a hot strip is produced with a thickness of 2.5 to 10 mm and the last roll pass in the austenitic temperature range;

- A cooling section for cooling the hot strip;

- A pair of scissors for cutting the cooled hot strip; and

- A winding device for winding the hot strip to bonds.

Since the rolling train is located immediately after the continuous casting plant, neither a heater nor a descaler is arranged between the end of the continuous casting plant and the first rolling stand of the rolling train. Thus, the thin slab strand enters after the continuous casting with high surface and core temperature in the rolling mill and is there

rolled exclusively from its casting heat out to a hot strip, the last pass in austenitic

Temperature range takes place.

For the compactness of the continuous casting, it is advantageous if an arcuate portion of the strand guide a

Arc radius R from 4.5 to 6.5 m, preferably 5 to 6 m. In order not to undercool the edge regions of the thin slab strand, it is favorable if the secondary cooling at several positions within the strand guide in each case at least two in a width direction of the

Thin slab strand has movable spray nozzles.

To take as much casting heat from the continuous casting in the rolling mill, it is advantageous if in the area between the end of a horizontal portion of the

Strand guide and the first stand of the rolling mill

Heat insulation panels (so-called. Encopanels or English, heat

Covers), preferably a thermal tunnel attached.

In addition, it has proved to be beneficial if the

horizontal distance between two stands of the rolling mill between 3 and 6 m, in particular between 4 and 5 m, and / or the length of the cooling section between 10 and 60 m.

Finally, it is favorable if a lifting device is arranged between the pair of scissors and a pair of drive rollers, wherein the hot strip can be clamped by the drive rollers and the hot strip can be lifted by the lifting device, whereby the hot strip can be pulled away from the scissors. In a so-called cobble in the cast roll mill, the hot strip is first separated by the shears, then the hot strip lying behind the shears in the direction of transport is clamped by driver rolls and lifted by the lifting device. This will make the hot strip of the scissors

pulled away, so that a collision with the subsequent hot strip is prevented.

Brief description of the drawings

Further advantages and features of the present invention will become apparent from the description of non-limiting embodiments. The following schematic

Figures shown show: 1 shows a schematic representation of a casting-rolling composite plant

2 shows a representation of the continuous casting plant from FIG. 1

3 shows an illustration of the different sections of the strand guide of the continuous casting plant

4 shows a representation of several width-adjustable

Spray nozzles in the strand guide of the continuous casting plant

5 shows an illustration of a temperature profile during the production according to the invention of a thin, hot-rolled finished strip in a cast roll mill

6a and 6b each show a representation of a front view of a lifting device in a non-raised and a

7a to 7e the steps when starting a

Gieß-Walz-Verbundanlage according to the invention

DESCRIPTION OF EMBODIMENTS FIG. 1 schematically shows a cast-rolled composite plant according to the invention for producing a hot-rolled hot strip of steel. The pretreated by a vacuum treatment liquid steel with a hydrogen content -S 1 ppm is in pans to the ladle turret (in Fig 2 top left hinged in the pan turret pan 8 is shown) of the continuous casting 1 and transported there via a

Casting 9 poured into the formed as a funnel mold continuous mold 2. In the continuous casting mold 2, a thin slab strand is formed with a thin strand shell having a thickness of 55 mm and a width of 1700 mm

having. The partially solidified thin slab strand is continuously drawn out of the continuous casting mold 2 and supported in the following strand guide 4, guided and by Spray nozzles (see Figure 4, reference numeral 19) a

Secondary cooling further cooled. The strand guide 4 has a vertical portion 4a, an arcuate portion 4b with a plurality of strand guide segments, and a

horizontal section 4c (see Figure 3). 2, two strand guide segments 6 are shown. each

Strand guide segment 6 has in each case a plurality of strand guide rollers that can be hydraulically attached to the thin slab strand 3, as a result of which the thin slab strand 3 is reduced to a thickness of 45 mm. In the thickness reduction, the thin slab strand 3 preferably has a liquid core 5 (in what is known as a liquid core reduction) or a partially liquid core. To keep the mechanical Verforumungsarbeit in the subsequent rolling steps in the rolling train 14 as low as possible and to keep the casting heat in the thin slab strand 3, the secondary cooling in the strand guide 4 and the casting speed v _c by a control or

Control device 20 of the continuous casting 1 such

set that the thin slab strand 3 at a

predetermined position within the strand guide 4th

solidified (see Figure 3). The continuous caster 1 is at a casting speed v _c of 6 m / min and with a specific throughput D = h. v _c = 0.27 m ² / min operated.

The operation of the continuous caster 1 controlled or controlled by the controller 20 such that the sump tip (i.e., the through-solidification point) of the continuous casting machine 1

Thin slab strand 3 at a predetermined position

is within the strand guide 4, is e.g. from WO 01/03867 AI known. The corresponding disclosure is hereby incorporated by reference into this application.

The reduced thickness, solidified, not descaled and endless thin slab strand 3 is immediately after the

Continuous casting through four stands F1 ... F4 of rolling mill 14 rolled to a hot-rolled strip with a thickness of 3.2 mm (see the following table with the individual thickness decreases and average temperatures). before Fl to F2 to F2 to F3 to F4

Thickness [mm] 45 19 9 4.5 3.2

0 Temperature 1090 1040 950 885 830

[° C]

Tab. 1

The hot strip is then cooled by a cooling section 16 to winding temperature, cut by the scissors 17 and wound up by one of the winding devices 18 into coils.

Should a problem occur in the rolling train 14 or the cooling section 16, the hot strip of the scissors 17

the hot strip section lying behind the shears 17 in the direction of transport is clamped by drive rollers (for example a pair of drive rollers 18a of the winding devices 18) and the foot of the hot strip section by the lifting device

10 pulled away from the scissors 17. The hot strip coming from the rolling train 14 is too short by the scissors 17

Hot strip sections chopped and e.g. by means of scrap buckets

11 promoted.

FIG. 2 shows further details of the continuous casting plant 1

shown.

FIG. 3 shows the vertical section 4a, the

arcuate portion 4b and the horizontal portion 4c of the strand guide 4 of the continuous casting 1 closer. Due to the straight through mold 2 and the vertical section 4a, inclusions in the molten steel accumulate on the meniscus, these are taken up by the casting powder and used in the form of casting slag for strand lubrication. The radius R of the arcuate strand guide 4b is shown in FIG. 3 and is approximately 5 m in the continuous casting plant according to the invention. The thin slab strand 3 occurs immediately (i.e.

descaled) after the horizontal section 4c into the first rolling stand F1 of the rolling train. Furthermore, the figure shows how a thin slab strand 3 with a liquid core. 5 the continuous casting mold 2 leaves and is reduced in thickness in the strand guide 4. The reduced thickness thin slab strand 3 is driven by one as a pair of

Strand guide rollers trained extractor 7 pulled out of the continuous mold 2. To the swamp tip of the

Thin slab strand 3 to keep at a certain position, the casting speed v _c , optionally the

Thickness reduction of the thin slab strand 3 by the

Strand guide segments 6, by the control or

Control device 20 controlled or regulated set.

4, a width-adjustable secondary cooling in the strand guide 4 is shown. For both narrow 3 and wide thin slab strands 3 ^Λ overcooling of the edge portions of the strand 3 is prevented by the outer two spray nozzles 19 are formed displaceable both in the width direction and normal to the strand surface. The spray nozzles 19 are connected via spray nozzle holder 21, 21 ^Λ with a linear drive 22, which shifts the spray nozzles 19 in the axial direction of the linear drive 22. The central spray nozzle 19 can either fixed or as

represented, also be designed to be displaceable.

In Fig 5, the temperature profile in ° C at the

According to the invention, production of a hot-rolled hot strip in a cast-rolled composite plant according to the invention

shown; the figure corresponds to the above

Description and the information given in Tab 1. The core temperature is dotted, the surface temperature is dashed and the average temperature is shown in solid lines. A grade DD11 molten steel is subjected to a vacuum treatment prior to continuous casting, whereby the hydrogen content in the liquid steel is reduced to ^ 1 ppm. In the

Continuous mold 2 of the continuous casting 1 is a

partially solidified thin slab strand 3 having a thickness of 55 mm and a width of 1700 mm formed and reduced by a liquid core reduction to a solidified thin slab strand 3 with a thickness of 45 mm thickness. The solidified Thin slab strand 3 leaves the horizontal section 4c of the continuous casting plant 1 with a casting speed of v _c = 6 m / min and thus with a specific throughput D = hv _c = 0.27 m ² / min. The solidified thin slab strand 3 is supplied without being descaled to a rolling train 14 and reduced there by four rolling stands F1 to F4 to a thickness of 3.2 mm. It is noteworthy that, even at the very low specific throughput of D = 0.27 m ² / min, the last roll pass in the rolling stand F4 takes place in the austenitic state of the steel. Subsequently, the hot strip is cooled in the cooling section 16, cut and tied

wound up.

FIG. 6a shows the lifting device 10 from FIG. 1 in a non-lifted state and in a raised state in FIG. 6b. In the non-raised state, all the underlying roller table rollers - including the two liftable lifting rollers 13 - form a horizontal roller table 12. If, as in the

Outlined in Figure 1, a problem occurs during or after continuous operation in the rolling mill 14, the endless hot strip is cut by the scissors 17, clamped and the two lifting rollers 13 are moved upwards (see the raised state in Figure 6b). Since the hot strip 15 is clamped at a position behind the scissors 17, the foot of the hot strip section is pulled away from the scissors 17.

This avoids a collision between the pulled-away hot strip section and the hot strip following from the rolling train 14 in a simple manner. Figures 7a to 7e show schematically the

Process steps when starting a cast-rolled composite plant according to the invention.

FIG. 7a shows the cast-rolled composite plant before

Casting start of the continuous casting plant. The continuous casting mold 2 is sealed in a fluid-tight manner by a cold strand 30 which comprises a cold strand head 31 and a link chain 32. After casting the continuous casting 1 of the dummy strand 30th pulled out by the driver rollers 18a in the transport direction T from the cooled continuous mold 2. By casting the cold strand head 31 welded to the subsequent thin slab strand 3 (see Figure 7b), wherein the Dünnbrammen- strand 3 of the strand guide 4 (usually strand guide rollers of a strand guide segment 6) supported, guided and further cooled by a secondary cooling.

In FIG. 7b, the cold strand 30 has already largely been pulled out of the continuous casting plant 1. Since the dummy strand 30

much colder and harder than the following one

Thin slab strand 3 is, are the rolling stands F1 ... F4 of the rolling train 14 in a driven-up state, so that the cold strand 30, the rolling train 14 can pass through unrolled. This will damage the work rolls of the

Roll stands F1 ... F4 prevented.

In FIG. 7c, the cold strand 30 has already passed the rolling train 14 and the cooling section 16 and was cut off from the thin slab strand 3 by the scissors 17. In the illustrated state, the cold strand 30 was separated from the scissors 17 by driven rollers 33 and driver rollers.

According to FIG. 7d, the cold strand 30 has been deposited on a roller table 12 by driven rollers 33 behind the drive rollers 18a of the winding device 18. In addition, the

Casting speed v _{c of} the continuous casting 1 increases and the thin slab strand 3 through the strand guide 4th

reduced in thickness, whereby a wedge-shaped wedge piece 34 is formed. The unrolled thin slab strand 3 and the

Wedge piece 34 are chopped by the scissors 17 and the chopped material from the roller table 12 between the scissors 17 and the winding device 18 ausfördert, for example. By pushing the shredded material in the horizontal direction across the

Transport direction T. In addition, the rolling stands Fl to F4 of the rolling train 14 are now gradually to the

reduced thickness thin slab strand 3 employed and the thin slab strand 3 rolled into a hot strip 15. In the FIGURE is the time shown at which the first

Roll stand Fl is employed on the thickness-reduced thin slab strand 3. The rolling stands F2 to F4 are still passed unrolled.

Finally, in FIG. 7e, all rolling stands F1... F4

employed, so that the thickness-reduced thin slab strand 3 is rolled into a hot strip 15 with a thickness between 2.5 and 10 mm. The hot strip 15 is cooled in the cooling section 16, then transversely split on bundle length or weight of the scissors 17 and wound up in the winding device 18 into coils.

In contrast to prior art cast-rolling mills, the plant according to the invention is considerably simpler, since it can be used, for example. only a single pair of scissors 17 needed and gets along completely without Entzunderer. In addition, the start-up of the cast-rolling composite plant is much easier. Nevertheless, the manufactured hot strip 15 is excellently suitable as a precursor for classic cold rolling.

Although the invention in detail by the preferred

While embodiments have been further illustrated and described, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the present invention

To leave invention.

LIST OF REFERENCE NUMBERS

continuous casting plant

ended mold

Thin slab

strand guide

vertical section of the strand guide arcuate section of the strand guide horizontal section of the strand guide liquid core

Strand guide segment

Extraction device

pan

distribution trough

lifting device

scrap bucket

roller table

liftable lifting roller

rolling train

hot strip

cooling section

scissors

winding device

driver rolls

nozzle

Control or regulating device

Spray nozzle holder

linear actuator

dummy bar

Dummy bar head

link chain

driven roller

wedge

Thickness of the reduced thickness thin slab roll stand

specific throughput

radius Transport direction Casting speed

Claims

claims

A process for the endless production of a coiled hot strip (15) of steel in a cast-rolling composite plant, wherein the cast-rolling composite plant

- A continuous casting plant (1) for producing an endless thin slab strand (3, 3 ^Λ );

- A rolling mill (14) having a plurality of rolling stands (F1 ... F4) for hot rolling of the thin slab strand (3, 3 ^Λ ) to the hot strip (15);

- A cooling line (16) for cooling the hot strip (15);

- A pair of scissors (17) for cutting the hot strip (15); and

- A winding device (18) for winding the

Hot strip (15);

comprises, comprising the steps:

- Continuous casting of a molten steel in one

Continuous mold (2) of the continuous casting plant (1) to the

Thin slab strand (3, 3), wherein the thin slab strand (3, 3 ^Λ ) at the exit from the continuous casting mold (2) a

liquid core (5), a thickness of 45 to 70 mm, preferably 55 to 65 mm, and a width of 900 to 2300 mm, preferably 1100 to 1900 mm;

- Supporting, guiding and reducing the thickness of the

Thin slab strand (3, 3 ^Λ ) in a strand guide (4) of the continuous casting plant (1), wherein the reduced thickness

Thin slab strand (3, 3 ^Λ ) has a thickness h of 35 to 52 mm, preferably 40 to 50 mm, a casting speed v _c and a specific throughput D = hv _c of 0.45 m ² / min>D> 0.27 m ² / min;

- Hot rolling of the endless, reduced thickness

Thin slab strand in the rolling train (14), wherein the

Thin slab strand exclusively from its casting heat out by at least three, more preferably by four,

Rolling passes to the hot strip (15) with a thickness of 2.5 to

10 mm is rolled and the last pass is made in the austenitic temperature range of the steel;

- cooling the hot strip (15) in the cooling section (16); - cutting the cooled hot strip (15); and

Winding the hot strip (15) into coils in the

Winding device (18). 2. The method according to claim 1, characterized in that a control or regulating device (20) of the continuous casting plant (1) using a mathematical model

an actual position of a sump tip along the

Transport path of the thin slab strand (3, 3 ^Λ ) in the

Strand guide (4) and

- An actual temperature profile along the transport path of the thin slab strand (3, 3 ^Λ ) in the strand guide (4) and in normal planes to continuously calculated and the

Thin slab strand (3, 3 ^Λ ) taking into account a setpoint position of the sump tip in the strand guide (4)

is cooled continuously regulated so that the actual position of the sump tip of the desired position as possible

corresponds. 3. The method according to any one of the preceding claims, characterized in that the actual temperature _Ti of the hot strip (15) after the last rolling pass in the rolling train (14) and prior to cooling in the cooling section (16) is measured and the cooling of the Thin slab strand (3, 3 ^Λ ) in the

Strand guide (4) and / or the casting speed v _{c is} set regulated, so that the actual temperature Tn _st a target temperature Ti _So n as possible corresponds.

4. The method according to any one of the preceding claims, characterized in that the thickness reduction, a soft reduction in an area with still liquid core (5) or

semi-liquid core of the thin slab strand (3, 3 ^Λ ) applies.

5. The method according to any one of the preceding claims, characterized in that the actual temperature T ₂ i _{st of} the endless

Hot strip (15) is measured after cooling in the cooling section (16) and cooling nozzles of the cooling section (16)

controlled temperature-controlled so that the actual Temperature 2i _s t a target temperature T2S ₀ 11 as possible

corresponds.

6. The method according to any one of the preceding claims, characterized in that a federal government is then pickled and cold rolled by a plurality of rolling passes in a cold rolling mill to a thickness of 0.3 to 7 mm.

7. A method for starting a cast-rolling composite plant, wherein the cast-rolling composite plant

- A cooling line (16) for cooling the hot strip (15);

- A pair of scissors (17) for cutting the hot strip (15); and

- A winding device (18) for winding the

Hot strip (15);

comprises, comprising the steps:

- Casting the continuous casting plant (1), wherein a

Cold strand (30) of a continuous casting mold (2) of the

Continuous casting plant (1) seals, in the transport direction (T) from the continuous mold (2) is pulled out;

- supporting and guiding a cold strand (30)

subsequent thin slab strand (3, 3 ^Λ ) in one

Strand guide (4) of the continuous casting plant;

Passing the rolling stands (F1 ... F4) of the rolling train (14), wherein the cold train (30) passes through the rolling train (14) without being rolled;

- Cutting the dummy bar (30) by the scissors

(17);

- Outfeeding the dummy bar (30), wherein the dummy bar (30) preferably the winding means (18) and passes in

Transport direction (T) is stored behind it; - Parting the unhardened thin slab strand (3, 3 ^Λ ) in a shredded material by the scissors (17) and conveying out the shredded material;

preferably increasing a casting speed v _c and reducing the thickness of the thin slab strand (3, 3 ^Λ ) in the

Strand guide (4);

- Setting up the rolling stands (F1 ... F4) to the

Thin slab strand (3, 3 ^Λ ) and hot rolling of the

Thin slab strand (3, 3 ^Λ ) to a hot strip (15);

- cooling the hot strip (15) in the cooling section (16);

- cutting the cooled hot strip (15); and

Winding the hot strip (15) into coils in the

Winding device (18). 8. The method according to claim 7, characterized in that when increasing the casting speed a specific

Throughput D with D = hv _c of 0.45 m ² / min>D> 0.27 m ² / min

is set. 9. Cast rolled composite plant for the production of a

wound hot strip (15) made of steel, in particular for carrying out the method according to one of the preceding claims, comprising

- A continuous casting plant (1), the

- A continuous mold (2) for the continuous production of a

Thin slab strand (3, 3), which at the exit from the continuous casting mold (2) a liquid core (5), a thickness of 45 to 70 mm, preferably 55 to 65 mm, and a width of 900 to 2300 mm, preferably

1100 to 1900 mm; and

- A strand guide (4) for supporting, guiding and reducing the thickness of the thin slab strand (3, 3 ^Λ ) with a secondary cooling for cooling the thin slab strand (3, 3), wherein the

Thin slab strand (3, 3 ^Λ ) after the thickness reduction, a thickness of 35 to 52 mm, preferably 40 to 50 mm, a casting speed v _c and a specific throughput D = hv _c of 0.45 m ² / min>D> 0.27 m ² / min;

includes;

- A rolling train (14) for hot rolling the

thickness-reduced thin slab strand (3, 3 ^Λ ), wherein the immediately after the continuous casting (1) arranged

Rolling line (14) at least three, more preferably exactly four, rolling stands (F1 ... F4), wherein through the

Hot rolling the thin slab strand (3, 3 ^Λ ) exclusively from its casting heat out a hot strip (15) is produced with a thickness of 2.5 to 10 mm and the last roll pass in the austenitic temperature range;

- A cooling line (16) for cooling the hot strip (15);

- A pair of scissors (17) for cutting the cooled

Hot strip (15); and

- A winding device (18) for winding the

Hot bands (15) to bonds.

10. Cast-rolling composite plant according to claim 9, characterized

in that the continuous casting installation (1) has a control or regulating device (20) and a mathematical model for continuous calculation

- An actual position of a sump tip along the transport path of the thin slab strand (3, 3 ^Λ ) in the

Strand guide (4) and

- An actual temperature profile along the transport path of the thin slab strand (3, 3 ^Λ ) in the strand guide (4) and in normal planes to it

comprises, wherein the control or regulating device (20) at least one controlled variable from the group of a cooling intensity in the secondary cooling and the casting speed v _c taking into account a desired position of a sump tip in the strand guide, so that the actual position of the sump tip of the thin slab strand (3, 3 ^Λ ) corresponds to the desired position as far as possible.

11. Cast-rolling composite plant according to claim 9 or 10, characterized in that an arcuate portion (4 b) of Strand guide (4) has a radius of curvature R of 4.5 to 6.5 m, preferably 5 to 6 m.

12. Cast-rolling composite plant according to one of claims 9 to 11, characterized in that in the region between the end of a horizontal portion (4c) of the strand guide (4) and the first stand (Fl) of the rolling train (14)

Heat insulation panels, preferably a thermal tunnel, are attached.

13. Cast-rolling composite plant according to one of claims 9 to

12, characterized in that the horizontal distance between two rolling stands (Fl, F2, F3, F4) of the rolling train (14) is between 3 and 6 m, in particular between 4 and 5 m.

14. Cast-rolling composite plant according to one of claims 9 to

13, characterized in that the length of the cooling section (16) is between 10 and 60 m.

15. Cast-rolling composite installation according to one of claims 9 to

14, characterized in that between the scissors (17) and a pair of drive rollers (18a) is arranged a lifting device (10), wherein the hot strip (15) through the

Driver rollers (18 a) clamped and the hot strip (15) can be lifted by the lifting device (10), whereby the

Hot strip (15) of the scissors (17) can be pulled away.