EP1506828A1 - Casting roll - Google Patents

Abstract

Casting roller (1) comprises a stress relieving zone (E) provided between the core (3) and a sleeve (5).

Description

The invention relates to a casting roll for a continuous casting plant for the continuous casting of metal strips according to the features in the preamble of patent claim 1.
Casting involves pouring liquid steel or other non-ferrous metals between two horizontally or vertically stacked, counter-rotating, laterally sealed casting rolls. During this process, the strip solidifies between the two casting rolls and continues to run continuously in the process.

Casting rollers of the common type have a cylindrical core, usually made of Steel and a jacket connected to it. As material for the coat come for Steel casting usually uses high thermal conductivity materials such as copper or copper alloys used. For casting non-ferrous metals Usually steel jackets applied.

For the connection between the core and the shell of the casting roll come today in essentially two methods of application. This is on the one hand the so-called hot isostatic pressing. This jacket and core are under high pressure and Temperature joined together.

The second, most widely used method is a shrinking technique Press connection between sheath and core before. Before joining, the jacket is heated and pushed over the core. Upon cooling, the press connection is formed Shrinking the coat.

The shrinking process creates tensile stresses in the jacket. In the operational Use during the casting process may depend on the rigidity of the Construction and the forces acting to a deflection or rebound of the Casting roller come. As a result arise in the edge zones of the casting roll Load voltages that are related to the acting stresses from the shrinking process overlap. These stresses can be under load at the acting Alternating stress lead to cracking.

The invention is based on the prior art, the object of a, for the operational use improved casting roll to create, in the stress is reduced during operation.

The solution of this problem consists according to the invention in a casting roll according to the features of claim 1.
Thereafter, a relaxation zone is provided between the core and the shell of the casting roll, through which a local reduction of the shrinkage stresses takes place. This results in a reduction in the reference voltages in the areas under heavy load. In this way, the formation of fatigue and the formation of cracks due to stress is prevented, resulting in an increase in the life of a casting roll. In addition, this improves the running properties of the casting roll.
The relaxation zone is formed by a profiling of the outer diameter of the core and / or the inner diameter of the shell. According to the features of claim 2 it is provided that the relaxation zone is formed by a partial reduction of the outer diameter of the core, whereas claim 3 provides that the relaxation zone is formed by a partial enlargement of the inner diameter of the shell.
A particularly advantageous embodiment of the basic concept of the invention is according to the features of claim 4 in that the relaxation zone is located in the central longitudinal region of the core and / or the jacket. In this case, the invention makes the knowledge that the maximum stress resulting from the superposition of the shrinkage stresses and the load stresses is established in the middle region of the casting roll.

Figur 1

technisch vereinfacht in einem vertikalen Längsschnitt eine erste Ausführungsform einer erfindungsgemäßen Gießwalze;

Figur 2

eine zweite Ausführungsform einer erfindungsgemäßen Gießwalze;

Figur 3

den Mantel der Gießwalze gemäß Figur 1 im vertikalen Längsschnitt und

Figur 4

den Kern der Gießwalze gemäß Figur 2 im vertikalen Längsschnitt.

As a result, the shrinkage stresses are specifically reduced by the relaxation zone, so as to reduce the reference voltage under load.
The relaxation zone can be in the outer regions of a roller in the presence of corresponding loads of the rollers, for example in unfavorable cooling conditions according to claim 5.
Practical experiments have shown that depending on the continuity and design of the casting roll, the expansion zone should be provided at a length which corresponds to 0.2 to 0.8 times the total length of the core and / or the shell (claim 6).
Conveniently, the relaxation zone has a radial extent of 0.6 to 0.2 mm, as provided by claim 7. A radial extension of 1 mm is considered to be particularly effective.
In the casting roll according to the invention core and jacket are reliably connected by a positive connection due to the shrink fit with sufficiently high pressure. Nevertheless, the shrinkage stresses can be selectively reduced in the highly loaded areas and thus achieved a reduction in the comparison voltage.
The invention is explained in more detail with reference to exemplary embodiments illustrated in the drawings. Show it:

FIG. 1

technically simplified in a vertical longitudinal section, a first embodiment of a casting roll according to the invention;

FIG. 2

a second embodiment of a casting roll according to the invention;

FIG. 3

the shell of the casting roll according to Figure 1 in vertical longitudinal section and

FIG. 4

the core of the casting roll according to Figure 2 in vertical longitudinal section.

Figures 1 and 2 each show a casting roll 1 and 2 for a casting mill for continuous casting of metal strips. Each casting roll 1, 2 has a cylindrical core 3, 4 made of steel and a shrunk thereon 5, 6 made of a copper alloy. On the representation of other component components, such as shaft, bearings and other attachments or cooling channels, has been omitted for simplicity.
As mentioned above, the sheath 5 and 6 and the core 3 and 4 are connected by shrinking techniques. By the shrinking process arise in the jacket 5, 6 tensile stresses. These interfere with the operational load voltages to the so-called reference voltage. This maximum stress arises in the central region B of a casting roll 1 and 2, respectively. In these regions B, crack formation under load occurs in the acting alternating stress.
To reduce the resulting from the shrink fit between the core 3, 4 and sheath 5, 6 shrinkage stresses between the core 3, 4 and the sheath 5, 6 a relaxation zone E is provided. This relaxation zone E is introduced specifically in the area B, in which in the operational use of the casting roll 1, 2 can be expected under load with the highest stress.
In the embodiments of the casting rolls 1 and 2 illustrated here for an aluminum casting rolling plant, the expansion zone E is provided in the middle length region of the shell 5, 6. In the case of the casting roll 1, as can also be seen in particular from FIG. 3, the expansion zone E is formed by a region-wise enlargement of the inside diameter D _{I of} the shell 5. The relaxation zone E here has a radial extent s of 0.6 to 2.0 mm, preferably 1 mm.
In the casting roll 2, the expansion zone E is formed by a partial reduction of the outer diameter D _{A of} the core 4 (see also FIG. Here, the outer diameter D _A is partially reduced radially in the middle length region of the core 4. Again, the relaxation zone E has an extension s between 0.6 and 2.0 mm, preferably 1 mm.

In practice, the relaxation zone E, depending on the embodiment of a casting roll 1, 2 and use case of different lengths. Here, the length L _{E of} the relaxation zone E between 0.2 to 0.8 x the total length L of the core 3, 4 and / or the jacket 5, 6 are.

After shrinking the coats are 5 and 6 respectively flat on the cores 3 and 4 on. The relaxation zone E is in the embodiments shown here for Clarification of the invention shown oversized. In practice, according to the Do not shrink any gap between sheath 5, 6 and core 3, 4. Through the targeted in the Areas of highest stress relaxation zone E becomes a partially achieved reduction of shrinkage stresses. These lead into the high burdened areas to a reduction of the maximum load.

REFERENCE NUMBERS:

1 -

casting roll

2 -

casting roll

3 -

core

4 -

core

5 -

coat

6 -

coat

B -

Area

E -

relaxation zone

D _I -

Inner diameter v. 5, 6

D _A -

Outside diameter v. 3, 4

s -

radial extent of E

L -

Length of 3, 4 or 5, 6

Claims (7)

Casting roll for a continuous casting plant for the continuous casting of metal strips, which has a substantially cylindrical core (3, 4) and a jacket 5, 6 shrunk thereon of a material of high thermal conductivity, such as copper or a copper alloy, characterized in that between the core (3, 4) and the jacket (5, 6) a relaxation zone (E) is provided. Casting roller according to claim 1, characterized in that the expansion zone (E) is formed by a partial reduction of the outer diameter (D _A ) of the core (4). Casting roller according to claim 1, characterized in that the expansion zone (E) is formed by a partial enlargement of the inner diameter (D _I ) of the jacket (5). Casting roller according to one of claims 1 to 3, characterized in that the expansion zone (E) in the central longitudinal region of the core (3, 4) and / or the jacket (5, 6). Casting roller according to one of claims 1 to 3, characterized in that the expansion zone lies in the outer regions of the core and / or the jacket. Casting roller according to one of claims 1 to 5, characterized in that the expansion zone (E) has a length (L _E ) which is 0.2 to 0.8 times the total length (L) of the core (3, 4) and / or of the jacket (5, 6). Casting roller according to one of claims 1 to 6, characterized in that the expansion zone (E) has a radial extent (s) of 0.6 to 2.0 mm, preferably of 1.0 mm.

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