WO2002064289A1

WO2002064289A1 - Installation for producing a hot-rolled strip

Info

Publication number: WO2002064289A1
Application number: PCT/EP2002/000935
Authority: WO
Inventors: Gerald Hohenbichler; Manfred Leutgöb
Original assignee: Voest-Alpine Industrieanlagenbau Gmbh & Co.
Priority date: 2001-02-12
Filing date: 2002-01-30
Publication date: 2002-08-22
Also published as: MXPA03007155A; ATA2092001A; EP1360023A1; AT409830B; KR20030071890A; US20040079512A1; CN1501847A; JP2004520171A

Abstract

The invention relates to an installation for producing a hot-rolled strip from a metal melt according to a two-roll casting method. The aim of the invention is to increase the melt throughput in the runner basin beyond the capacity of a single-strand casting installation that works according to the two-roll casting method and at the same time to substantially reduce the casting times of a batch at minimum investment and operating costs. To this end, the invention uses an installation configuration wherein a foundry ladle (1) comprising a melt outlet (5) is associated with a runner basin (6) that receives the metal melt from the foundry ladle (1). Said single runner basin (6) is provided with at least two bottom outlets (8a, 8b) for passing on the metal melt to two two-roll casting devices (10a, 10b). Every casting gap (13a, 13b) is associated with one of the bottom outlets (8a, 8b) of the runner basin (6) and the two casting gaps (13a, 13b), in terms of their longitudinal extension, are disposed at an angle of 15° to 180° with respect to one another or are off-set in parallel from one another.

Description

Plant for the production of a hot strip

The invention relates to a plant for the production of hot strip from a metal melt by the two-roll casting process with two two-roll casting devices.

Such a system for the production of thin, near-net-shape hot strip, preferably steel strip, by the two-roll casting process essentially consists of two spaced-apart, driven and counter-rotating casting rolls, the axes of rotation of which lie in a horizontal plane. They form a casting gap, the lateral boundary of which is formed by side plates pressed onto the end of the casting rolls. Side plates which can be pressed vertically onto the casting roll lateral surfaces are also known for this purpose. The two casting rollers and the side plates form a melt space into which molten metal is introduced through a dip tube. On the two cooled jacket surfaces of the casting rolls, metal melt solidifies into strand shells, which combine to form a cast strip in the narrowest gap between the casting rolls. The metal strip, which is conveyed vertically downward, is subsequently deflected into the horizontal, subjected to further processing steps in downstream treatment facilities and wound into metal coils.

A system using the two-roll casting method described is already known from AT-B 406 938. Two parallel two-roll casters are supplied with melt independently of one another, each two-roll castor being assigned a separate ladle turret and a separate distributor vessel. The metal strip produced is wound into bundles, the bundles are transported from both casting plants to a common rolling plant and processed there. This system arrangement doubles the production capacity.

In the vertical two-roll casting process, the strip casting speed is limited to 15 to 150 m / min due to the heat dissipation limited to a short distance on the surface of the casting roll at a strip thickness of 1.5 to 5 mm. The achievable production capacity in such a system is thus limited to values between approx. 0.5 and 1.5 t / min and a strip width. This corresponds to a maximum production capacity of 100 t / h for a conventional single-strand system with casting widths up to 1300 mm. In ladles with a capacity of 150 1 molten metal and more, as they are often used, this leads to casting times of more than two hours and thus to undesirably different casting conditions over the casting time.

In certain continuous casting plants, in particular in casting plants for producing metal strands of small width, such as billet continuous casting plants and pre-block casting plants, it is quite common to minimize the casting time per ladle by using a multi-strand casting plant. Here, the molds and the downstream strand guides are arranged closely adjacent. The melt is fed from a common ladle through a common distributor through a plurality of pouring openings to the individual molds. A system of this type, in which a large number of billet strands of very small cross-section can be produced by means of tubular molds arranged in a semicircle, is already known from DE-A 19 08 648. In accordance with this mold arrangement, the individual cast strands are discharged in a radial manner at the same angular distance. With such small cross sections, the problem of arranging two molds for casting strands with strip cross sections and a large length / width ratio with a limited distributor size does not arise.

Occasionally, two-strand belt casting machines have become known (EP-B 347 662, JP-A 62-187505), the molds of which are supplied with melt by a distributor. However, these molds do not work according to the vertical two-roll casting process, but are equipped with caterpillar molds or conventional plate molds, which may have a central extension area for the immersion pouring tube. The two-roll casting system required for the two-roll casting process requires much more space than molds of other types because of the lateral roll mounting, the side plates that can be adjusted on the front side of the casting rolls with their hydraulic adjustment mechanisms and the drives of the casting rolls in the axial direction. Given these structural conditions and the desired large product range, it is not possible to move the casting rolls so closely together in the axial direction that a common distributor for two two-roll casting plants could be arranged above them in the usual way. The dimensions of a distribution vessel are limited by the need for uniform heating before it is put into operation and the desired melt guidance and conditioning in the distribution vessel. Distributor vessels with a longitudinal extension of more than 10 m are hardly technically feasible and lead to very high metal volumes in relation to the total throughput of the two two-roll casting machines and wetted refractory lining surface and thus to increased consumption of refractory material and loss of output.

The object of the invention is therefore to avoid these disadvantages and difficulties and to propose a casting plant operating according to the two-roll casting process, with which it is possible to significantly increase the melt throughput in the distributor vessel beyond the capacity limit of a single-stranded casting plant working according to the two-roll casting process and at the same time the casting times of one Reduce batch significantly. Another object of the invention is to ensure the conditions for the molten metal, in particular with regard to a constant casting temperature over the casting time, without additional heating and to keep the dimensions of the distribution vessel, in particular the distance between the floor outlets, small. Another object of the invention is to find a system configuration in which as many system components as possible are used together in several production lines.

This object is achieved according to the invention in that a ladle with a melt outlet is assigned a distributor vessel for taking over the molten metal from the ladle, in that this single distributor vessel is equipped with at least two bottom outlets for transferring the molten metal to two two-roller pouring devices, in that at least one of the bottom outlets for each pouring gap is assigned to the distribution vessel and the two pouring gaps are arranged with respect to their longitudinal extension at an angle α of 15 ° to 180 °, preferably 45 ° to 120 °, in particular 60 ° to 120 ° to one another. A favorable arrangement results if the two casting gaps are arranged at an angle ot of approximately 90 ° with respect to one another with respect to their longitudinal extent.

An advantageous system design is achieved if each two-roll casting device forms a production line with the downstream strip treatment devices and the production lines supplied with metal melt from a common distribution vessel are at an angle of 15 ° to 180 °, preferably 45 ° to 120 °, in particular 60 ° to 120 ° are arranged. Due to the angular position of the two production lines to each other, they can move closer together in the area of the actual two-roll caster and the distance between the central feed positions for the molten metal is minimized and the distribution vessel is shortened. A preferred system arrangement results if the production lines supplied by a common distributor vessel with molten metal are arranged at an angle β of approximately 90 ° to one another. The arrangement of belt deflection devices in the production lines can be avoided if the angle α, which defines the position of the casting nips of the two two-roll casting devices, is equal to the angle β, which defines the position of the two production lines to one another.

Further advantages of the arrangement according to the invention result if common service areas for at least one, preferably at least two of the following applications are arranged in the smaller angular range between two adjacent two-roll casting devices and the strip treatment devices downstream of them:

Gießwalzenwerkstätte,

Gießwalzenwechselstation,

- roll changing station,

- Roll grinding, plant control station, product logistics.

Synergy effects from reduced investment costs and savings in operation and maintenance also result in other system components. In some areas, duplicate equipment in the maintenance and logistics area is avoided, system monitoring is simplified and work for the operating team is made easier.

An arrangement of two two-roll casting devices, which also reduces or minimizes the length of the distributor vessel, results compared to an arrangement of two adjacent two-roll casting devices with aligned casting gaps if the two casting gaps are arranged parallel and offset with respect to their longitudinal extent. The production lines supplied by a common distributor vessel with molten metal are preferably arranged so as to lead away from one another.

The arrangement of the casting nips or production lines according to the invention has proven to be particularly advantageous, in particular in the case of angular positions of the production lines relative to one another between 45 ° and 120 °, if at least one roll stand is arranged after each two-roll casting device. Roll stands require space on the drive side for the drive units of the rolls and space on the operator side for roll changing devices. Preferred angular positions of the production lines to each other enable the arrangement of roll changing stations, the associated warehouse management and, if applicable, the roll grinding shop in a spatially closed area of the production hall between the two roll stands.

Effective ladle management is achieved if the ladle is supported in a carrying device, this carrying device is formed by a ladle turret which can be rotated about a vertical axis and has at least two receptacles for ladles, and the melt outlet of the ladle in the pouring position is approximately in the middle above the distributor vessel, preferably in the center of the area a projection of a T-shaped distribution vessel is arranged. The distributor vessel can also be trough-shaped or V-shaped and in this way equate to the T-shaped distributor.

The transfer of the molten metal from the distributor vessel to the two-roll casting plant takes place in a manner which does not disturb the strand shell formation on the surfaces of the casting roller if the bottom outlets in the distributor vessel comprise immersion pouring tubes which each project centrally into a free melt receiving space between two cooperating casting rollers of the two-roller casting devices.

For the reasons already described above, the floor outlets in the distribution vessel are not more than 8.5 m apart.

The invention is described in more detail below with reference to several exemplary embodiments, which are illustrated in the drawings in a schematic representation, with FIG. 1 showing a longitudinal section through a system for implementing the two-roll casting method according to the prior art, and FIG. 2a in a plan view of the system according to the invention with the arrangement of two

Production lines illustrated at an angle of 90 °, Fig. 2b defines the angles α and β in the arrangement according to the invention, Fig. 3a shows a top view of this system with an arrangement of two production lines at an angle of 180 ° and Fig. 3b in one Top view schematically represents a variant of the arrangement according to FIG. 3a.

An overall system for producing a steel strip from a molten steel using the two-roll casting method already described at the beginning, as is customary in the prior art, is shown schematically in FIG. 1 in a longitudinal section and limited to the most important system components. Casting ladles 1 filled with molten steel are removed from the smelting operation with metallurgical vehicles or one not shown Hall crane brought to the casting plant and used by this in recordings 2 of a ladle turret 4 rotatable about a vertical axis 3. From the ladle 1 in the pouring position, the molten steel flows through a melt outlet 5 into a distributor vessel 6 and from there through a bottom outlet 8 formed by an immersion pouring tube 7 to the two-roller casting device 10. The two-roller casting device 10 is essentially supported by two in a support frame (not shown) in support bearings , Driven and counter-rotating casting rolls 11, 12 formed. The casting rolls 11, 12 which are arranged at an adjustable distance from one another, together with side plates arranged at the end and not shown in FIG. 1, form a casting gap 13 which is limited in its longitudinal extent and a melt receiving space 14 in which solidified strand shells form on the casting roll surfaces and pass through the casting gap 13 the rotation of the casting rolls 11, 12 are brought together to form a cast metal strip 15. The metal strip 15 is subsequently conveyed out of the casting gap 13, deflected into the horizontal, conveyed further by pairs of drive rollers 16, 17 to a roll stand 18 and held there under tension. In the further production process, the metal strip 15 is cooled as it passes through cooling devices 19, cross-sectioned with scissors 20 in accordance with the required coil weights and wound into coils in a reel device 21. Other devices, not shown, such as a loop pit for speed compensation between individual production facilities, trimming shears for treating the strip edges of the metal strip, evacuation chambers to avoid scale formation on the metal strip, intermediate heating devices, etc., are usually integrated in such systems.

A possible embodiment of an arrangement of two production lines 23, 24, each incorporating a two-roll casting device 10a, 10b of the type described above, for carrying out the vertical two-roll casting process is shown in FIG. 2a. The two production lines 23, 24 are arranged at an angle β of 90 ° to one another. The casting gaps 13a, 13b of the two-roll casting devices 10a, 10b with the casting rolls 11a, 12a and 11b, 12b, which are arranged at an angle α of 90 ° to one another, are covered by a distributor vessel 6 which extends obliquely over both two-roll casting devices 10a, 10b and are supplied with molten metal , For this purpose, the bottom outlets 8a, 8b are positioned exactly above the casting nips 13a, 13b of the two-roll casting devices 10a, 10b and ensure a symmetrical entry of the metal melt into the melt receiving space 14 (FIG. 1). With the ladle turret 4, the ladle 1 is brought into a pouring position above the distributor vessel 6, in which the molten metal flows into a projection 25 of the T-shaped distributor vessel 6. Analogous strip treatment devices are arranged in both production lines 23, 24, of which only one roll stand 18a, 18b is shown in the schematic illustration in FIG. 2a to achieve a reduction in thickness, structure improvement, surface smoothing etc. on the metal strip and the reel devices 21a, 21b , In the hall area between the two adjacent production lines 23, 24, in addition to the roll stands 18a, 18b, areas for the roll changing stations 30a, 30b and, if appropriate, further areas, not specified, for the common storage of roll sets and the roll grinding are provided. Through the sewing area the same

Belt treatment facilities and the possibility of combining them result in favorable working conditions for operating and maintenance personnel with short transport routes and shared logistics. Similar synergy effects arise, for example, at the casting roll changing station and the casting roll workshop, at the plant control station and the product logistics.

2b, the casting nips 13a, 13b of the two casting roll devices are shown schematically at an angle α of 60 °. The angle β between the two production lines 23, 24 is also 60 °, so that the casting gaps 13a, 13b are always positioned normally to align the production lines 23, 24. Angular positions .alpha. And .beta. Which differ in their size are also possible, but force the arrangement of belt deflection devices in or at the beginning of the production lines 23, 24.

3a shows a further possible embodiment of an arrangement of two production lines 23, 24, each incorporating a two-roll casting device 10a, 10b for carrying out the vertical two-roll casting process, the casting nips 13a, 13b, the two-roll casting devices 10a, 10b and the production lines 23, 24 at an angle of 180 °, ie parallel and offset from each other. At the center of the system is the ladle turret 4 and the distributor vessel 6, from which the two production lines 23, 24 are oriented in opposite directions and the cast strip accordingly runs through the production lines in opposite directions.

FIG. 3b shows a variant of the system arrangement shown in FIG. 3a, the production lines 23, 24 and accordingly also the casting nips 13a, 13b and the casting roller devices being arranged in parallel and laterally offset from one another. The invention is not restricted to the illustrated embodiments. The individual system components can be used in various modified forms. It is within the scope of the invention to provide other floor-based support devices for the ladles instead of the ladle turret, such as movable ladle trucks. A pouring crane on which the ladle hangs can also be used and replace the ladle turret. The shape of the distribution vessels can be adapted to one another depending on the angular positions of the production lines and can also be designed as an essentially rectangular trough or V-shaped distribution vessel. Such modifications in the design of the distribution vessel also fall under the scope of protection of a T-shaped distribution vessel. A multi-stand rolling device can be used to achieve higher reduction rates in the individual production lines.

Claims

claims:

1. Plant for producing hot strip from a metal melt according to the two-roll casting method with two two-roll casting devices, each of the two-roll casting devices (10a, 10b) being formed by two casting rolls (11a, 12a; 11b, 12b) each forming a casting gap (13a, 13b), characterized in that a ladle (1) with a melt outlet (5) is assigned a distributor vessel (6) for taking over the molten metal from the ladle (1), that this single distributor vessel (6) with at least two bottom outlets (8) for forwarding the Metal melt for two two-roll casting devices (10) is equipped such that each casting gap (13) is assigned at least one of the bottom outlets (8a, 8b) of the distributor vessel (6) and the two casting gaps (13a, 13b) with respect to their longitudinal extent at an angle α of 15 ° to 180 °, preferably from 45 ° to 120 °, in particular from 60 ° to 120 ° to each other.

2. Plant according to claim 1, characterized in that the two casting gaps (13a, 13b) are arranged at an angle α of approximately 90 ° with respect to their longitudinal extent.

3. Plant according to claim 1 or 2, characterized in that the production lines (23, 24) supplied with metal melt from a common distribution vessel (6) to one another at an angle β of from 15 ° to 180 °, preferably from 45 ° to 120 ° , in particular from 60 ° to 120 °.

4. Plant according to claim 3, characterized in that the production lines (23, 24) supplied with metal melt from a common distribution vessel (6) are arranged at an angle of approximately 90 ° to one another.

5. Plant according to claim 3 or 4, characterized in that the angle α, which defines the position of the casting gaps (13a, 13b) to one another, is equal to the angle β, which determines the position of the production lines (23, 24) to one another.

6. Plant according to one of the preceding claims, characterized in that in the angular range between two adjacent two-roll casting devices (10a, 10b) and common service areas for at least one, preferably at least two of the following applications are arranged in the belt treatment facilities (production lines) downstream of them:

Gießwalzenwerkstätte,

Gießwalzenwechselstation,

Roll-changing station

roll grinding,

Conditioning helm,

Product logistics.

7. Plant for the production of hot strip from a metal melt according to the two-roll casting process with two two-roll casting devices, each of the two-roll casting devices (10a, 10b) being formed by two casting rolls (11a, 12a; 11b, 12b) each forming a casting gap (13a, 13b) , characterized in that a ladle (1) with a melt outlet (5) is assigned a distributor vessel (6) for taking over the molten metal from the ladle (1), that this single distributor vessel (6) with at least two bottom outlets (8a, 8b) To forward the molten metal to two two-roll casting devices (10a, 10b), it is equipped that at least one of the bottom outlets (8a, 8b) of the distributor vessel (6) is assigned to each casting gap (13a, 13b) and the two casting gaps (13a, 13b) with respect to them Longitudinal extension are arranged parallel and offset from one another.

8. Plant according to claim 7, characterized in that the production lines (23, 24) supplied with metal melt by a common distributor vessel (6) are arranged to lead away from one another.

9. Plant according to one of the preceding claims 1 to 8, characterized in that each two-roll casting device (10a, 10b) is followed by at least one roll stand (18a, 18b).

10. Plant according to one of the preceding claims 1 to 9, characterized in that the ladle (1) is supported in a support device, that this support device from a rotatable about a vertical axis turret (4) with at least two receptacles (2) for ladles (1) is formed and the melt outlet (5) of the ladle (1) in the casting position is arranged approximately centrally above the distributor vessel (6), preferably centrally in the region of a projection (25) of a T-shaped distributor vessel (6).

1 1. Installation according to one of the preceding claims 1 to 10, characterized in that the bottom outlets (8a, 8b) in the distributor vessel (6) comprise immersion pouring tubes (7) which are centered in a free melt receiving space (14) between two cooperating casting rollers (11a , 12a 1b, 12b) of the two-roll casting devices (10a, 10b) protrude.

12. Plant according to one of the preceding claims 1 to 11, characterized in that the bottom outlets (8a, 8b) in the distribution vessel (6) are not more than 8.5 m apart.