EP1286795B1 - Device for continuously casting metal, particularly steel - Google Patents

Abstract

For a further development a device for continuous casting of metal, in particular steel, with a metal mold with mold walls (1,18) and a mold cooling device and which can remove high thermal flows and can be subjected to thermal loads and, thereble, is suitable for use at high speeds, at least one mold wall (1,18) of the mold of this device should include a steel wall (2) and a support mesh (3) for this wall and the device further should be provided with magnetic field generator (3.2) for generating a magnetic field (3.1) acting on the mold steel wall (2) via the support mesh (3) for attracting the mold steel wall (2) to the support mesh (3), with the mold cooling device comprising spray cooling means.

Description

The invention relates to a device for the continuous casting of metal, in particular of steel, with a plate mold or a tubular mold with mold walls and with a mold cooling device. Such a device is used for casting different Strand formats, such as slabs, thin slabs, blooms or beam blanks. Here, the mold itself or the As in horizontal continuous casting, the strand oscillates. But the mold itself is arranged in one place and can therefore also be referred to as a stand mold become.

Such molds as a casting mold for continuous casting plants either consist of Mold plates, namely two plates for the mold wide plates and two plates for the mold corn sides, or from mold tubes.

These mold plates or mold tubes are made of copper and have in the Usually a thickness of 10 to 50 mm between the water cooling and the Melting steel side facing.

The choice of copper plate thickness depends on the heat loads or the heat flow, measured for example in MWh / m ² or MW / m ² . For example, continuous casting plants with a mold for slab formats with a thickness greater than 150 mm and a width of up to 3 m, which are driven at a casting speed of a maximum of approximately 2.5 m / min, have a heat flow of a maximum of 2 MW / m ² . The thickness of the copper plates of the mold is between 25 and 50 mm. In contrast, thin slabs, which are operated at casting speeds of up to 10 and in the future up to 15 m / min, have a maximum heat flow of 4-5 MW / m ² and copper plate thicknesses of 10 to 25 mm.

To meet the increasing heat flow with increasing casting speed to become, the copper wall would have to become ever thinner as the Water cooling. This is difficult, since thinner walls are always used worse the high water pressures of 5-15 bar, for a corresponding Ensure water speed of 5-15m / s, steadfast without deformation. In addition, there is the disadvantage that copper plates formed too thin at too high a thermal load on the cold-rolled copper Loss of strength if the recrystallization temperature is exceeded. Moreover there are problems with the assembly of very thin cocitia copper plates on the mold frame. The mold plates are usually opened the water boxes or the mold frame are mounted by means of bolts, which by means of of a thread can be screwed into the back of the copper plate. This is not possible with very thin plates; here the bolts must be on the Copper plates are welded on.

The invention has for its object a device of the generic type Art in such a way that the above disadvantages despite increasing the Pouring speeds no longer occur. in particular a device can be created for continuous casting with a mold, the high heat flows can be transported away and can withstand high thermal loads. Also the Assembly can be improved.

This object is achieved by the device with the features of claim 1 solved. Advantageous further developments are described in the subclaims.

According to the invention it is proposed that at least one mold wall be a Steel mold wall and a support grid for this steel mold wall includes that a magnetic field generator is available for generating a magnetic field that acts on the steel mold wall via the support grid and thus the steel mold wall pulls on the support grid, and that the Kokilienkühineinrichtung a spray cooling includes.

These features create a mold, which is a thin mold wall with high and controlled heat dissipation properties even at high Has casting speeds. The mold wall is exposed on the one hand a steel mold wall pointing towards the molten metal and on the other hand composed of a support grid to stabilize this steel mold wall. Due to the magnetic attraction, the steel mold wall can be simple to be assembled. Such a mold also has the particular advantage that the steel mold wall exposed to wear from the molten steel unlike a more expensive copper plate, fast and if necessary can be easily replaced by the high quality machining Used is "thrown away", i.e. fed back into the steel recycling process becomes. With the help of the proposed double wall consisting of thin steel wall and support grid, can be a simple and less expensive Kokitlen spray cooling are used. To avoid high mold cooling water pressures, for example having to build up to 15 or 20 bar, the spray cooling acts in the open chambers left by the support grid or passages, i.e. the thin steel mold wall is cooled immediately, but still experiences a relatively high support effect. When spray cooling the use of splash water is possible. Overall results in high Efficiencies with regard to the removal of heat a simple Mold design and therefore a relatively inexpensive mold. The invention Solution creates a mold that has thermal conduction would otherwise require a copper plate thickness of about 10 mm or more, which is easy to mount on a base frame and which is a mold cooling allows water side and at the same time is inexpensive.

The steel mold wall proposed according to the invention preferably has a thickness between 0.5 and 5 mm, its effect corresponds to one Copper plate with a thickness of 10 mm, but has constructive advantages and price advantages on.

The support grid preferably has a support wall with a wall inserted therein. chambers on, i.e. the individual chambers or breakthroughs of the grid are from surround the wall webs of the support wall, the magnetic field via the support walls is introduced into the mold wall.

The spray cooling for cooling the mold walls preferably comprises spray nozzles, the steel mold wall in the back of the support grid, i.e. cool through the freely accessible chamber areas or gaps in the grid. These spray nozzles of the mold spray cooling as well as the feeds for the Cooling medium, especially water, are in the support walls of the support grid fully or partially integrated. Overall, the support grid or the support walls formed thick in relation to the steel mold wall.

The proposed spray cooling has the advantage that the intensity of the spray cooling Functional to the energy flow in the mold wall over the mold height is adjustable. This energy curve shows approximately in the upper third of the mold a heat maximum. By spray cooling using individual, one above the other arranged, the intensity of the cooling can be adjusted in a controlled manner and thus to an energy curve with an energy maximum or a Energy club can be adjusted by cooling more intensely at this point becomes.

A further development of the device suggests that a device for control the surface temperature of the side of the liquid metal facing the Steel mold wall is in place to spray cooling if necessary to adapt a control mechanism to fluctuations in the surface temperature.

In addition to the fixation of the steel mold plate proposed according to the invention the mold plate can also be mechanically fixed to the support grid. For this purpose, a fixing device is proposed for fixing the steel mold wall for example a broadside in the middle of the broadside above the Mold height. In addition, the steel mold wall at the mold entrance or at The mold exit can be fixed horizontally. In addition to the broadsides, also the narrow sides, if they are also stabilized with a support grid, be fixed.

According to a particularly preferred embodiment, the support walls of the Support grids at their ends facing the steel mold wall, i.e. head side or on their head, are equipped with balls that act as (ball) bearings for one serve free, thermally induced, movement of the steel mold wall. To build In a fluid bearing, the balls are filled with a fluid medium, for example Water or gas. For this purpose, lines are introduced into the supporting walls, which extend perpendicular to the steel mold wall and which the balls or the ball cages on the end faces of the retaining walls with water or Supply gas.

So that the spray water after spraying onto the free rear wall areas the steel mold wall does not drain uncontrolled, should be after further training of the invention, the support grid has an outer frame encompassing the grid cover with a seal.

To the rear, i.e. to the side pointing away from the molten steel, that can either drain the used cooling medium freely, i.e. in an open atmosphere drain, or drain directed. In the second case there is preferably a collecting chamber provided at the lower part of the mold wall, which flows into a drain flows to bring the cooling water to a treatment plant if necessary. In the collecting chamber is over the support grid walls, here in particular a wall part of the support grid arranged at the bottom of a spray nozzle, returned cooling medium collected and discharged through the drain.

Fig. 1a

eine Seitenansicht auf eine Kokillenwand einer Kokille, hier eine Breitseite einer Kokille zum Gießen von Strängen in Rechteckformat, gesehen von der Seite der Stahlschmelze;

Fig. 1 b

eine Queransicht der Kokillenwand der Fig. 1a;

Fig. 2a

eine Queransicht einer Kokillenwand mit Spritzkühlung, die an die Energiestromverteilung über die Kokillenhöhe angepaßt ist,

Fig. 2b

die Darstellung des Wärmestromverlaufs über die Kokillenhöhe;

Fig. 3a

eine Schnittansicht einer Kokille mit Schmafseitenwand sowie mit einem Schmalseitenkörper zur Breiten- sowie zur Konizitätsverstellung;

Fig. 3b

eine Detailansicht der Kugellagerlösung im kopfseitigen Ende der Stützwände zur Lagerung der Stahlkokillenwand auf dem Stützgitter.

Further details and advantages of the invention result from the subclaims and from the following description, in which the embodiments of the invention illustrated in the figures are explained in more detail. In addition to the combinations of features listed above, features alone or in other combinations are also essential to the invention. Show it:

Fig. 1a

a side view of a mold wall of a mold, here a broad side of a mold for casting strands in rectangular format, seen from the side of the molten steel;

Fig. 1 b

a transverse view of the mold wall of Fig. 1a;

Fig. 2a

a transverse view of a mold wall with spray cooling, which is adapted to the energy flow distribution over the mold height,

Fig. 2b

the representation of the heat flow over the mold height;

Fig. 3a

a sectional view of a mold with Schmafseitenwand and with a narrow side body for width and conicity adjustment;

Fig. 3b

a detailed view of the ball bearing solution in the head end of the support walls for storing the steel mold wall on the support grid.

1a is the broad side 1 of a mold, the two broad and two narrow sides and for casting rectangular formats such as slabs or Thin slab is shown. This broad mold side is exemplary from a 2 mm thick steel mold wall 2. The steel mold wall 2, the Is part of a total mold wall, with the help of a magnetic field 3.1 is built up by a magnetic field generator 3.2 and this via a support grid 3 acts with support walls 11 on the steel mold wall 2, on the support grid 3 drawn. The steel mold wall 2 is preferably a layered steel mold wall 2.1, for example, from the layers of steel / copper or Copper / steel / copper or other metals instead of copper. The Magnetic field generators can preferably be a permanent magnet 3.4.

The steel mold wall 2 of 2 mm thickness corresponds with its specific thermal conductivity a copper wall of about 14 mm. For additional fixation a device 4.1 (shown schematically here) is provided which covers the broad side fixed with the width 17 and a height 16 in the vertical center line 4, causing thermal expansion symmetrical in both horizontal directions (here with arrows and the reference number 5) hike in half can.

Furthermore, the steel mold wall is at its upper edge 6 or lower edge 7 Chill mold also fixed to thermally uniformly in the vertical direction (here indicated with a vertical arrow and reference number 8) to be able to. The embodiment shown here is rod-shaped elements that are rotatable about their longitudinal axis.

In order not to build up a high mold cooling water pressure of up to 15 or 20 bar need to be in the chambers 9 of the support grid 3 or the gaps or Breakthroughs, with the help of a mold spray cooling 10, which comprises spray nozzles, the back of the steel mold wall 2 is cooled, as shown in FIG. 1b. The heated up Cooling water or return splash water 10.2 can freely over the support grid walls 11 or retaining wall struts, drain off. This can be done by splashing water be collected in a closed room or a collecting chamber 12, to be discharged via a drain 12.1 or in an open atmosphere 13 are dissipated (see FIG. 3a).

The outer frame of the rectangular, magnetized, support grid 3.1 is all around with a rubber seal 3.3 around the mold splash water 10 to prevent an uncontrolled exit.

The support walls 11 of the support grid 3 are in the head regions 11.1 with balls 11.2 equipped as normal bearings or as fluid bearings for the free serve thermally induced movement of the steel mold wall 2. Examples of Bearing points or balls 11.2 are shown in Fig. 1a. Instead of the equipment with balls, the support grid heads 11.1 can also be made of rounded Graphite heads 11.1.1 exist which promote the thermally induced sliding process should.

3b shows a detailed view of the embodiment of the ball bearing. It is a section of a retaining wall 11 with retaining wall head 11.1 from the head 11.1 picked up ball 11.2 for mounting the steel mold wall 2 or 2.1 shown. The ball bearing cage is connected via a line with a fluid 11.3. such as water or gas, is used to build a fluid bearing or hydro bearing serves. The between the support walls 11 and the webs of the grid 3 acting spray nozzles 10.1 are also shown.

Fig. 2a illustrates the use of the device according to the invention for continuous casting or mold with an immersion spout 23.2 which protrudes into the mold. With 24 is pouring slag, with 24.1 casting powder. The liquid steel 23.1 is poured into the mold via the immersion nozzle 23.2, the solidification beginning with the formation of a strand shell 23 on the mold walls. The casting speed v _c is marked with 25. The magnetic field 3.1 generated by the magnetic field generator 3.2 or 3.4 can be designed such that it influences the steel flow in the mold in the sense of an electromagnetic brake 3.1.1.

In Fig. 2a the mold wall temperature is at 15 that of the liquid steel facing side of the mold. To measure the temperature is a appropriate measuring or control device provided. 2a are also the embodiments of the storage with in the head of the support walls 3 integrated balls 11.2 or with rounded heads, preferably made of Graphite 11.1.1. A type of storage is preferably used, but it is also covered by the invention that the support wall with both Storage types is provided. With the mold shown in Fig. 2a with Spray cooling does not catch the return spray water 10.2, but rather flows open downwards, where it can then be caught below the mold becomes.

It is a preferred feature of the invention that the spray cooling or Parameters of the individual spray nozzles to the cooling requirements required in each case the mold can be adapted. In contrast to Fig. 2a therefore shows Fig. 2b shows the resulting energy lobe 14 over the mold height, i.e. a maximum of heat released in the upper third of the mold. The regulation is the Mold wall temperature 15 measured and the spray cooling over the mold height adjusted accordingly.

3a shows an embodiment of the mold with a view of a narrow side 18 In this embodiment, the broad sides of the mold are according to the invention trained, while the narrow sides are made of steel, but have no support grid. However, it is also covered by the invention that both the broad and narrow sides or only the narrow sides of the mold are designed according to the invention. In the embodiment shown the narrow sides 18 made of steel. The narrow side 18 is obtained by a slightly concave and / or internal convexity 18.1 high stability. It is on the actual narrow side body 19, the width adjustment 20 and Conicity adjustment 21 of the mold allows assembled. This type of construction leaves a water pressure of up to 20 bar in the range of conventionally trained Narrow side mold water cooling, here marked with 22. 22.1 is a water-displacing body. After another The narrow sides of the mold can also be of the prior art Correspond to technology and consist of water-cooled copper plates. The Components already explained in the other figures have corresponding ones in FIG. 3a Reference signs on.

Returning to the wall construction proposed according to the invention a casting mold for continuous casting with appropriate cooling can Chambers 9 or openings of the support grid 3 take any shape, rectangular shapes are shown, these chambers preferably have a honeycomb shape, these chambers 9 and 12 between the Support walls 11 extend.

Overall, a mold for continuous casting is created that controls a high level Heat conduction allowed as well as easy assembly, in particular Assembly of the steel mold wall. A control of the steel mold temperature can be done in the casting direction (vertical) as well as transversely to the casting direction (horizontal). The steel mold wall can serve as a type of disposable steel plate that a high-quality and expensive maintenance processing is unnecessary in the event of wear makes. A relatively simple mold spray cooling can be used which are functional to the energy club in their effect or intensity via the mold height is adjustable. Normal water spray can be used Chill mold has a simple construction at a relatively low cost.

LIST OF REFERENCE NUMBERS

1

Broad side of a slab mold

2

Steel mold wall, for example the broad side of a slab

2.1

layered steel mold wall, for example made of steel / Cu, Cu / steel / Cu or Me / steel / me

3

Support grid, grid

3.1

magnetic field

3.1.1

electromagnetic brake for calming the flow of the steel in the mold, EMBR

3.2

magnetic field generator

3.3

Seal, for example a rubber seal

3.4

permanent magnet

4

vertical center line of the broadside

4.1

Device for fixing the steel mold wall (2)

5

horizontal direction

6

Upper edge of the mold, mold entrance

7

Bottom edge of the mold, mold exit

8th

vertical direction, casting direction of a slab plant

9

Gaps, chambers of the support grid (3)

10

Kokillenspritzkühlung

10.1

Spray nozzles, nozzle head

10.2

Rewind splash

11

Support walls of the support grid (3) with chambers (9)

11.1

Head of the retaining wall

11.1.1

Head of the graphite retaining wall

11.2

Balls used as bearings for the free thermal movement of the Steel mold wall (2) are used

11.3

Fluid such as B. gas or water to build a fluid bearing or hydro bearing

12

closed room, mold injection cooling chamber (10)

12.1

splash expiration

13

open atmosphere of injection cooling (10)

14

energy club

15

Mold wall temperature on the side facing the liquid steel

16

mold height

17

mold width

18

narrow side

18.1

concave and / or convex shape of the heat-dissipating narrow side wall

19

Narrow side body

20

width adjustment

21

conicity

22

Conventional narrow side mold water cooling with water pressures by Max. 20 bar

22.1

water displacing body

23

strand shell

23.1

molten steel

23.2

A submerged nozzle

24

casting slag

24.1

casting powder

25

Casting speed, V _C

26

Honeycomb shape of the support grid (3)

Claims (21)

1. Device for continuous casting of metal, particularly steel, with a plate mould or a tube mould, with mould walls (1, 18), as well as with a mould cooling device, characterised in that at least one mould wall (1, 18) comprises a steel mould wall (2) as well as a support grid (3) for this steel mould wall, that a magnetic field generator (3.2) is present for generating a magnetic field (3.1), which acts by way of the support grid (3) on the steel mould wall (2) and thus draws the steel mould wall (2) onto the support grid (3), and that the mould cooling device comprises spray cooling means (10).
2. Device according to claim 1, characterised in that the steel mould wall (2) has a thickness between 0.5 and 5 mm.
3. Device according to claim 1 and 2, characterised in that the steel mould wall (2.1 ) consists of metal layers with at least one steel layer, preferably of the layers steel/copper or metal/steel/metal, wherein the metal is, for example, copper.
4. Device according to one of claims 1 to 3, characterised in that the support grid (3) comprises a support wall (11) with chambers (9) formed therein, wherein the magnetic field (3.1) is introduced into the steel mould wall (2) by way of the support walls (11).
5. Device according to one of claims 1 to 4, characterised in that the spray cooling means (10) comprises spray nozzles (10.1 ) which, in the chambers (9) of the support grid (3), cool the steel mould wall (2) at the rear side.
6. Device according to one of claims 1 to 5, characterised in that the intensity of the spray cooling means (10) is settable functionally with respect to the energy path in the mould wall over the mould height.
7. Device according to one of claims 1 to 6, characterised in that it comprises a device for checking the surface temperature (15) of the sides of the steel mould wall (2) facing the liquid metal.
8. Device according to one of claims 1 to 7, characterised in that the mould wall (1), which comprises a steel mould wall (2) as well as a support grid (3) for this steel mould wall (2), is one or both of the wide sides (1 ) of a mould for casting rectangular formats, particularly slab formats or thin slab formats, and that the respective steel mould wall (2) of a wide side (1) is fixed in the centre of the wide side over the mould height (16) by means of a fixing device (4.1 ).
9. Device according to one of claims 1 to 9, characterised in that the mould has a mould inlet (6) as well as a mould outlet (7) and that the steel mould wall (2) is horizontally fixed at the mould inlet (6) or at the mould outlet (7).
10. Device according to one of claims 1 to 9, characterised in that the support walls (11 ) of the support grid (3) are equipped at the ends thereof facing the steel mould wall (2) with balls (11.2), which serve as bearings for a free, thermally induced movement of the steel mould wall (2).
11. Device according to claim 10, characterised in that the balls (11.2) of the ball bearing are operable with the help of a fluid medium.
12. Device according to one of claims 1 to 11, characterised in that the support walls (11 ) of the support grid (3) have at the ends thereof facing the steel mould wall (2) support grid heads of graphite (11.1.1), which are preferably formed to be rounded.
13. Device according to one of claims 1 to 12, characterised in that the support grid (3) comprises an outer frame engaging around the support grid and that this outer frame comprises a seal (3.3) for controlling the return of the mould spray coolant (10.2), particularly water.
14. Device according to one of claims 1 to 13, characterised in that a collecting chamber (12) and a drain (12.1) are present for directed discharge of the coolant (10.2) sprayed onto the steel mould wall (2), wherein the coolant (10.2) which has flowed back by way of the support grid walls (11) is collected in the collecting chamber (12) and is discharged by way of the drain (12.1), or that the sprayed-on coolant (10.2) is discharged into the free atmosphere (13).
15. Device according to one of claims 1 to 14, characterised in that the mould walls forming the narrow sides (18) of the mould comprise a steel wall which has an inner convexity (18.1 ) for mechanical stability.
16. Device according to one of claims 1 to 14, characterised in that the mould walls forming the narrow sides of the mould consist of copper plates.
17. Device according to claim 15 or 16, characterised in that the respective steel narrow side (18) is mounted on a narrow side body (19), which allows setting of the width of the slab format and the conicity of the narrow sides.
18. Device according to one of claims 4 to 17, characterised in that the spray nozzles (10.1) of the mould spray cooling means (10) as well as the feeds for the coolant (11.3), particularly water, are wholly or partly integrated into the support walls (11 ) of the support grid (3).
19. Device according to one of claims 4 to 18, characterised in that the chambers (9) of the support grid (3) have a honeycomb shape.
20. Device according to one of claims 1 to 19, characterised in that the magnetic field generator (3.2) is a permanent magnet (3.4).
21. Device according to one of claims 1 to 20, characterised in that the magnetic field (3.1) generated by the magnetic field generator (3.2) also acts as an electromagnetic brake (3.1.1 ) on the flowing metal melt stream (23.1) in the mould.

Images