DE102022207236A1 - Casting roll for a continuous casting plant - Google Patents

Abstract

The present application relates to a casting roll (1) for a continuous casting system (2), preferably for use in a continuous casting system (2), comprising a shaft (3), a casting roll core (5) arranged coaxially on the shaft (3) and made of steel ), which is cylindrical and has a crown (8) on its outer surface (7), as well as a hollow cylindrical jacket body (9) which is arranged coaxially on the casting roll core (5) and is connected to it in a rotationally fixed manner and which is made of copper and/or a Copper alloy consists and has a casting roller surface (10).

Description

The present invention relates to a casting roll for a two-roll continuous caster, preferably for use in a two-roll continuous caster. In a further aspect, the present invention relates to a method for producing the casting roll according to the invention and furthermore to a continuous casting system comprising the casting roll according to the invention.

During thin strip casting using the so-called two-roll process, a strip-shaped strand is first cast directly from a molten metallic composition in a continuous casting system. Usual thicknesses of the band-shaped strand can be up to 10 mm. The strand produced is then fed to a rolling train and hot-rolled in this with thickness reductions in the range of 15 to 80%. The hot strip then obtained is thermally treated if necessary and finally wound into a coil.

A central part of such a continuous casting plant is the casting rolls, through which high heat flows must be dissipated. In addition to the surface quality of the cast strand or strip, the shape of the casting rolls also defines the strand or strip geometry and thus the later hot strip geometry or the flatness quality to be achieved. Due to the high heat flow, a bulge or crowning occurs in the outer jacket bodies, which are often made of copper, which significantly influences the geometry of the cast strand or strip.

The heat flow and the associated formation of the crowning is directly dependent on the process parameters set in each case, such as the cast metal quality, the casting thickness, the contact angle, the steel overheating, the casting atmosphere, etc. It follows from this that the geometry of the cast strand or strip also and in particular the thickness cross profile depends on the casting parameters, which has so far severely limited the flexibility of strip casting technology.

In order to reduce the formation of this crowning, the prior art teaches to use active actuators of hydraulic or thermal design. For example, this reveals WO 2018/141744 A1 a casting roll that has a large number of axially symmetrical expansion rings through which the crowning is attempted to be compensated for during the casting process.

Such active actuators cause enormous technical effort in the production of the casting rolls. These must be arranged at an effective location within the casting roll, which is technically particularly complex. In addition to the large amounts of water needed to cool the casting rolls, electrical and/or hydraulic energy must also be introduced into the rotating casting roll depending on the design, which makes production and maintenance considerably more difficult. This complexity leads to high production costs for the casting roll, which is designed as a wearing part, and also causes a correspondingly high CO2 footprint during use.

Against this background, the present invention is based on the object of providing a casting roll for a two-roll continuous casting system that is improved compared to the prior art, in particular to provide a casting roll for a two-roll continuous casting system that does not require active actuators and has a wide Casting parameter range enables an almost constant continuous casting profile.

Description of the invention

According to the invention the object is achieved by a casting roll with the features of patent claim 1.

The casting roll according to the invention for a two-roll continuous caster, which is preferably intended for use in a two-roll continuous caster, comprises a shaft; a casting roll core arranged coaxially on the shaft and made of steel, which is cylindrical and has a crowning on its outer surface; and a hollow cylindrical jacket body which is arranged coaxially on the casting roll core and is connected to it in a rotationally fixed manner, which consists of copper and/or a copper alloy and has a casting roll surface.

According to the invention, it is provided that the casting roll core made of steel has a camber on its outer surface and thus a contour that slopes in a defined manner towards its two axial ends. As a result, the shrink fit of the hollow cylindrical jacket body made of copper and/or of a copper alloy to the casting roll core can be adjusted in accordance with the expected deformation in the casting operation, which means that the installation of active actuators within the casting roll can be dispensed with. It has been shown that a casting roller designed in this way has a sensitivity of less than 20 μm over a wide casting parameter range, whereby an almost constant continuous casting profile can be achieved.

The casting roll core is designed as an integral part of the shaft and therefore forms a solid body. In an alternative embodiment variant, the casting roll core can also be designed as a separately designed component, which is then designed as a hollow cylindrical, arranged coaxially on the shaft and connected to it in a rotationally fixed manner.

Further advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically sensible manner and can define further embodiments of the invention. In addition, the features specified in the claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

In the context of the present invention, the term “crown” means that the outer lateral surface of the casting roll core has a convex shape in the axial longitudinal section. This convex shape can be curved to varying degrees depending on the length of the casting roll core, which can typically be in the range from 100 to 2300 mm.

In an advantageous embodiment variant, the crowning can therefore have at least two symmetrically designed areas which form the crowning of the outer lateral surface of the casting roll core. Each of these areas therefore has a radius that decreases in the direction of the distal ends of the casting roll core, starting from a point (apex) connecting the two areas. It is preferably provided that the decrease in radius is in a range that corresponds to a gradient of 0.05 to 3.0%.

In a further advantageous embodiment variant, the crowning can have a central part between the two symmetrically formed (edge) regions, which is then cylindrical. The crowning therefore comprises a central cylindrical region which has a constant radius over its axial extent, as well as two edge regions adjacent to the central region, each of which has a decreasing radius in the direction of the distal ends of the casting roll core. Here too it is advantageously provided that the decrease in radius is in a range which corresponds to a gradient of 0.05 to 3.0%.

In a further advantageous embodiment variant it is provided that the casting roll core comprises a plurality of cooling channels via which the hollow cylindrical jacket body can be cooled. It is particularly preferred in this context that the plurality of cooling channels are designed in the form of grooves which are introduced into the outer lateral surface of the casting roll core and which very particularly preferably extend axially. In contrast to the casting rolls known from the prior art, whose outer copper jacket comprises cooling channels and is water-cooled via these, it is provided here that the jacket body having the casting roll surface does not include such cooling channels, which usually have to be produced via technically very complex and cost-intensive deep hole drilling . This makes it possible for the jacket body made of copper and/or a copper alloy to be made particularly thin.

In a particularly advantageous embodiment variant, it is therefore provided that the jacket body having the casting roller surface has a radial thickness of a maximum of 50 mm, preferably a radial thickness of a maximum of 45 mm, more preferably a radial thickness of a maximum of 40 mm, even more preferably a radial thickness of a maximum 35 mm, and most preferably has a radial thickness of a maximum of 30 mm, which has a particularly advantageous effect on the manufacturing costs of the jacket body designed as a wearing part.

In a particularly advantageous embodiment variant, the casing body having the casting roller surface has a radial thickness in the range of 1 to 50 mm, more preferably a radial thickness in the range of 5 to 50 mm, and most preferably a radial thickness in the range of 10 to 50 mm on.

In a further advantageous embodiment variant it is provided that the casting roller surface is profiled. The profile of the casting roll surface is advantageously designed such that undesirable thermal and/or mechanical deformations of the jacket body can be compensated for. In addition, a defined profile that is favorable for the subsequent rolling process of the cast strip can be created.

In a further aspect, the present invention relates to a method for producing the casting roll according to the invention. According to the method, it is provided that a casting roll core made of steel, which is arranged on a shaft and is cylindrical and has a crowning on its outer surface, is first provided; and then a hollow cylindrical shell body made of copper and/or a copper alloy is positioned coaxially with the casting roll core and shrunk onto it. The jacket body points usually has a radial thickness that is uniform over the axial length, so that it adapts to the contour of the casting roll core after shrinking. It is therefore preferred that the casting roll is subjected to a further process step in which the outside of the casing body is removed to form a rotationally symmetrical casting roll surface and then, if necessary, profiled.

In addition, the present invention relates in a further aspect to a two-roller continuous casting system for the continuous casting of a metallic strand, comprising two casting rollers according to the invention which are arranged opposite one another and can be adjusted relative to one another.

Figure name

• 1 a eine erste Ausführungsvariante der erfindungsgemäßen Gießrolle in einer Schnittdarstellung,
• 1b eine zweite Ausführungsvariante der erfindungsgemäßen Gießrolle in einer Schnittdarstellung,
• 2a eine erste Ausführungsvariante einer Bombierung des Gießrollenkerns,
• 2b eine zweite Ausführungsvariante einer Bombierung des Gießrollenkerns,
• 3 eine Ausführungsvariante einer Stranggießanlage,
• 4 ein Diagramm, welches die Abhängigkeit der Bombierung vom Wärmestrom als Resultat der Gießparameter für eine aus dem Stand der Technik bekannte Gießrolle sowie für eine erfindungsgemäße Gießrolle aufzeigt.

The invention and the technical environment are explained in more detail below using the figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and to combine them with other components and findings from the present description and/or figures. In particular, it should be noted that the figures and in particular the proportions shown are only schematic. The same reference numbers designate the same objects, so that explanations from other figures can be used in addition if necessary. Show it:

• 1 a a first embodiment variant of the casting roll according to the invention in a sectional view,
• 1b a second embodiment variant of the casting roll according to the invention in a sectional view,
• 2a a first embodiment variant of a crowning of the casting roll core,
• 2 B a second embodiment variant of a crowning of the casting roll core,
• 3 an embodiment variant of a continuous casting plant,
• 4 a diagram showing the dependence of the crowning on the heat flow as a result of the casting parameters for a casting roll known from the prior art and for a casting roll according to the invention.

In 1a a first embodiment variant of the casting roll 1 according to the invention is shown in a sectional view, which is for use in a continuous casting system 2, as shown in 3 is shown is provided.

In the present embodiment variant, the casting roll 1 is formed from several individual elements which are connected to one another in a rotationally fixed manner via suitable connection types that are familiar to those skilled in the art. The basic element of the casting roll 1 forms a shaft 3, which has a drum-shaped body 4, which serves as a seat for the further construction of the casting roll 1.

As can be seen from the illustration, the casting roll 1 comprises a casting roll core 5 which is arranged coaxially on the shaft 3 or coaxially on the drum-shaped body 4 and is connected to it in a rotationally fixed manner and is hollow cylindrical and made of steel. Furthermore, the casting roll core 5 has a crowning 8 on its outer surface 7, which can be designed differently depending on the length of the casting roll core 5 ( 2a and 2 B) .

In the 2a and 2 B a part of the casting roll core 5 is shown in a sectional view. The crowning 8 consists of the in 2a shown embodiment variant from two mutually mirror-symmetrical areas 8a, 8b. Each of these areas 8a, 8b therefore has a decreasing radius in the direction of the distal ends of the casting roll core 5, as symbolized by the two arrows R1 and R2.

In contrast, this shows 2 B a crowning 8, which has a central part 8c, which is cylindrical, between the two (edge) regions 8a, 8b which are designed to be mirror-symmetrical to one another.

Furthermore, the casting roll 1 comprises a hollow cylindrical jacket body 9 which is arranged coaxially on the casting roll core 5, in particular on the latter and is thus non-rotatably connected to it, and which in the present case consists of pure copper. The outer surface of the jacket body 9 forms the casting roller surface 10, which comes into contact with the molten steel composition during the process and can be profiled. In the present case, the casing body 9 has a radial thickness of 25 mm at its thickest point, which varies over its axial length due to the formation of the rotationally symmetrical casting roller surface 10.

As can also be seen from the illustration, the jacket body 9 has no axial cooling bores. Rather, it is provided that it is cooled via its inside 11. In this respect, the casting roll core 5 has a plurality of cooling channels 12 on its outer surface 7 are formed in the form of axially extending grooves 13. In the area of the end faces of the casting roll core 5, radially extending supply and discharge channels 14, 15 are also provided, which form part of a cooling system 16 of the casting roll 1 and via which the cooling channels 12 can be supplied with cooling water. In the present case, part of the cooling system 16 is formed in cover elements 17, which are connected in a rotationally fixed manner to the drum-shaped body 4 via screw connections 18.

In 1b a second embodiment variant of the casting roll 1 is shown in a sectional view, which, in contrast to the previous embodiment variant, has a casting roll core 5 designed as an integral part of the shaft 3.

In 3 an embodiment variant of a two-roller continuous casting system 2 is shown, which is intended for the continuous casting of a metallic strand 19 and comprises two casting rollers 1 which are arranged opposite one another and can be adjusted relative to one another.

The two-roller continuous casting system 1 shown comprises a frame 20 in which the two casting rolls 1 are mounted in chocks (not shown). One of the casting rolls 1 is typically operated fixed to the frame, whereas the second casting roll 1 is adjustable by means of a hydraulic positioning device, so that a casting gap between the two casting rolls 1 can be adjusted.

The two casting rollers 1, which are cooled from the inside, usually rotate in opposite directions at the same angular speed and, together with ceramic side plates arranged on the front side (not shown), form a rotating mold. The molten metallic composition, for example a molten steel, is fed to the melt sump via a ladle (not shown) via a distributor 21 which comprises an immersion pipe 21. When the melt comes into contact with the cooled casting rolls 1, heat is removed from it so that it solidifies on the casting roll surfaces 10 of the rotating casting rolls 1. The layer that solidifies on the casting rollers 1, also called the band shell, grows over time and is transported by the rotation of the casting rollers 1 in the direction of the narrowest roller gap and there combined with a second band shell to form a band or strand.

In 4 a diagram is shown which shows the dependence of the crowning on the heat flow as a result of the casting parameters for a casting roll 1 known from the prior art and a casting roll 1 according to the invention. A D1200 casting roll with a width of 350 mm and a copper jacket body with a radial thickness of 150 mm was used. The sensitivity shown in the diagram (comparative example) shows an example of the dependence of the crowning on the operating point. The difference shown here of 0.055 mm per casting roll 1 severely limits the usability of the strip produced. In contrast to this, the casting roller 1 according to the invention has a sensitivity of less than 0.02 mm.

Reference symbols

1

casting roller

2

Continuous casting plant

3

Wave

4

drum-shaped body

5

Casting roll core

6

Connection

7

Outer surface of casting roll core

8th

Bombing

8a

(edge) area

8b

(edge) area

8c

middle part

9

Sheath body

10

external surface/casting roller surface

11

Inside of the jacket body

12

Cooling channels

13

grooves

14

feed channel

15

discharge channel

16

Cooling system

17

Lid element

18

Screw connection

19

metallic strand

20

Frame

21

Distributor

22

Dip tube

L

length

R

Arrow

QUOTES INCLUDED IN THE DESCRIPTION

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

Cited patent literature

• WO 2018141744 A1 [0005]

Claims (10)

Casting roll (1) for a two-roll continuous casting system (2), preferably for use in a two-roll continuous casting system (2), comprising a shaft (3), a casting roll core (5) arranged coaxially on the shaft (3) and connected to it in a rotationally fixed manner and made of steel, which is cylindrical and has a crown (8) on its outer surface (7), and a hollow cylindrical jacket body (9) arranged coaxially on the casting roll core (5) and connected to it in a rotationally fixed manner, which consists of copper and/or a copper alloy and has a casting roll surface (10). Casting roller (1). Claim 1 , wherein the casting roll core (5) comprises a plurality of cooling channels (12) via which the hollow cylindrical jacket body (9), preferably via its inside (11), can be cooled. Casting roller (1). Claim 2 , wherein the plurality of cooling channels (12) are designed in the form of grooves (13) which are introduced into the outer lateral surface (7) of the casting roll core (5) and which preferably run axially. Casting roll (1) according to one of the preceding claims, wherein the jacket body (9) having the casting roll surface (10) does not comprise any cooling channels. Casting roll (1) according to one of the preceding claims, wherein the jacket body (9) having the casting roll surface (10) has a radial thickness of a maximum of 50 mm, preferably a radial thickness of a maximum of 45 mm, more preferably a radial thickness of a maximum of 40 mm, still more preferably has a radial thickness of a maximum of 35 mm, and most preferably a radial thickness of a maximum of 30 mm. Casting roll (1) according to one of the preceding claims, wherein the casting roll surface (10) is profiled. Casting roll (1) according to one of the preceding claims, wherein it has no thermal and/or hydraulic actuators. Method for producing a casting roll (1) for a two-roll continuous casting system (2), initially comprising a shaft (3) and a casting roll core (5) made of steel arranged on the shaft (3), which is cylindrical and on its outer lateral surface (7) has a camber (8), and then a hollow cylindrical jacket body (9) made of copper and / or a copper alloy is positioned coaxially to the casting roll core (5) and is shrunk onto it. Procedure according to Claim 8 , in order to form a rotationally symmetrical casting roller surface (10), the outside of the jacket body (9) is removed and then profiled if necessary. Two-roller continuous casting system (2) for the continuous casting of a metallic strand, comprising two oppositely arranged and mutually adjustable casting rollers (1) according to one of the preceding Claims 1 until 7 .

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