Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEM AND METHOD FOR CASTING AND ROLLING METAL
Field of the Invention
The invention concerns an installation and a method for
casting and rolling metal, especially steel, by means of
casting installations and a downstream rolling train.
For the sake of clarity, we shall first define a few
terms that are used synonymously in the context of the present
specification. The terms "thin slabs" and "slabs" each refer
to very thin slabs (5-35 mm thick), thin slabs (35-90 mm
thick), medium-thickness slabs (90-150 mm thick), or near-net
strip (20-50 mm thick).
In the context of the present specification, the term
"horizontal thin-slab casting installation" is synonymous with
a horizontal strip casting installation, especially a BCT
installation (belt casting technology) or a DSC installation
(direct strip casting).
In the context of the present specification, the term
"vertical thin-slab casting installation" covers especially
the following types of installations: a thin-slab casting
installation in accordance with compact strip production
(CSP), a vertical casting installation with a downstream
bending and straightening installation for a strand with a
still-liquid crater, a vertical casting installation with a
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downstream bending and straightening installation for a
completely solidified strand (e.g., a CSP installation), or a
bow-type casting installation.
Prior Art
The document EP 1 708 830 Bl discloses a CSP installation
designed for the production of thin slabs with a thickness of
about 50 mm. In particular, this document describes a two-
strand installation. The strands produced in this
installation are fed to a common rolling train. In this
connection, the strands are conveyed by so-called pivoting
conveyors. In addition, there is a parallel rolling
installation for conventional thick slabs or medium-thickness
slabs, which is arranged downstream of a two-stand blooming
train, with which slabs to be charged to the CSP line are
reduced to a thickness of about 50 mm. An upstream roughing
stand or plate-rolling stand is provided for charging slabs
into the CSP line.
In patent EP 1 318 876 B1, two CSP installations with a
downstream rolling train are provided. One of these
installations is used to produce carbon steel, while the other
is used to produce special steel. The steel slabs are bent in
these CSP installations.
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In view of the prior art described above, the technical
objective of the present invention is to further develop a
previously known installation and a previously known method
for casting and rolling metal in such a way that they are also
suitable for the production of high alloy steels or super
alloy steels and the production of thin strip.
Disclosure of the Invention
The technical objective is achieved by the installation
of the invention for casting and rolling metal, which
comprises at least a first and a second casting line for
casting slabs and means for conveying slabs cast in the first
casting line into the second casting line, as well as a
rolling train for rolling the cast slabs, wherein the first
casting line is designed as a horizontal thin-slab casting
installation, which comprises at least one charging vessel for
a melt and one horizontally running conveyor belt downstream
of the one or more charging vessels in the casting direction,
and wherein the second casting line is likewise designed as a
horizontal thin-slab casting installation or as a vertical
thin-slab casting installation, which comprises at least one
mold for the vertical casting of slabs and a bending and
straightening device for bending the vertically cast slab into
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a horizontal position, and wherein a rolling train for rolling
the cast slabs is arranged downstream of one of the two
casting lines, and the two or more casting lines and the means
of conveyance are designed in such a way that the slabs cast
with each one of the two or more casting lines can be fed to
the rolling train.
The installation in accordance with the invention allows
better utilization of a rolling train. In addition, an
existing rolling train can be better utilized by expansion
with additional casting lines. In addition, the provision of
a horizontal thin-slab casting installation makes it possible
to produce high alloy or super alloy steels, including, for
example, crack-sensitive steels and especially steels with a
high aluminum content, since the thin slabs do not come into
contact with casting flux in the horizontal thin-slab casting
installation as a result of the traveling mold or conveyor
belt. As a result of the combination with the horizontal
thin-slab casting installation, a fine grain structure is also
realized due to rapid solidification and a low segregation
tendency. Furthermore, oscillation marks on the cast product
can be avoided by a traveling mold. Possible cracking,
bending or straightening damage is also avoided. In addition,
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standard steels can also be produced by the additionally
provided thin-slab casting installation. All together, the
production program or spectrum is thus considerably expanded
compared to known installations. The use of thin-slab
technology also makes it possible directly to produce strips
with a thickness of less than 15 mm, which greatly reduces the
rolling work in the rolling train.
In a preferred embodiment of the installation, each of
the two or more casting lines is designed as a horizontal
thin-slab casting installation, which is followed by the
rolling train for rolling the slabs cast in the horizontal
thin-slab casting installations. With this type of
arrangement, even an installation that comprises only
horizontal thin-slab casting installations can be operated in
a cost-efficient way.
In another preferred embodiment of the installation, the
two or more casting lines are designed in a way that makes it
possible to cast slabs of such small thickness that a roughing
stand is not necessary for rolling the cast slabs before they
enter the rolling train. This type of arrangement saves
space, energy, and expense.
In another preferred embodiment of the installation, the
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thin-slab casting installation is designed for casting and
rolling slabs with a thickness of 40 mm to 120 mm, and/or the
horizontal thin-slab casting installation is designed for
casting and rolling slabs with a thickness of 5 mm to 35 mm
and preferably 10 mm to 20 mm.
In another preferred embodiment of the installation, the
one or more horizontal thin-slab casting installations are
designed for casting high alloy and super alloy steels.
In another preferred embodiment of the installation, at
least one temperature-adjusting device, especially a furnace,
is arranged downstream of the conveyor belt of the one or more
thin-slab casting installations in the direction of casting,
and/or at least one temperature-adjusting device, especially a
furnace, is arranged downstream of the bending device of the
one or more thin-slab casting installations in the direction
of casting.
In another preferred embodiment of the installation, the
means for conveying slabs cast in one of the two or more
casting lines to another of the two or more casting lines
consist of conveyors, especially pivoting conveyors, and/or
the conveyors are designed in such a way that the slabs are
conveyed into a section of the temperature-adjusting device of
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the other of the two or more casting lines.
In another preferred embodiment of the installation, the
two or more casting lines are arranged parallel to each other
and/or side by side.
In another preferred embodiment of the installation, the
installation comprises a total of three casting lines arranged
parallel side by side, and the rolling train for rolling the
slabs cast in the casting lines is arranged downstream of the
middle of the three casting lines in the direction of casting.
In addition, the invention comprises a method for casting
and rolling metal with at least two casting lines, which
hereafter are also referred to as the first and second casting
lines, for casting slabs, especially with the installation
according to one or more of the embodiments described above,
wherein thin slabs are cast horizontally in at least one of
the casting lines, and thin slabs are likewise horizontally
cast in at least one other casting line, and/or slabs are cast
vertically and/or in a curve and are bent into a horizontal
direction during or after the casting, wherein the cast slabs
are then fed to exactly one rolling train. The advantages of
the method of the invention are largely the same as those of
the installation of the invention.
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In a preferred embodiment of the method, the horizontally
cast thin slabs consist of steels with an aluminum content of
up to 10%.
In another preferred embodiment of the method, the
horizontally cast thin slabs consist of steels with an
aluminum content of 1-3%.
In another preferred embodiment of the method, the
horizontally cast thin slabs consist of carbon steels, low
alloy steels, high alloy steels or peritectic steels.
Brief Description of the Figures
The figures, which illustrate specific embodiments of the
invention, will now be briefly described. Further details are
provided in the Detailed Description of the Specific
Embodiments that follows the brief description.
Figure la is a schematic top view of an embodiment of an
installation of the invention, in which a horizontal thin-slab
casting installation can be connected by pivoting conveyors
with a two-strand thin-slab casting installation.
Figure lb is a perspective view of the installation
according to Figure la but with a common distributing launder
for the two-strand vertical thin-slab casting installation.
Figure lc is a schematic top view of an embodiment of an
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installation of the invention analogous to Figure la but with
a shorter temperature-adjusting section.
Figure id is a perspective view of the installation
according to Figure ic.
Figure 2a is a schematic top view of an embodiment of the
invention with a thin-slab casting installation together with
a downstream rolling train and two horizontal thin-slab
casting installations that can be connected with this
installation by means of pivoting conveyors.
Figure 2b is a perspective view of the installation
according to Figure 2a.
Figure 3a is a schematic top view of an embodiment of the
invention with a horizontal thin-slab casting installation
together with a downstream rolling train and two additional
horizontal thin-slab casting installations that can be
connected with this installation by means of pivoting
conveyors.
Figure 3b is a perspective view of the installation
according to Figure 3a.
Figure 4a is a schematic top view of an embodiment of the
invention with three horizontal thin-slab casting
installations, which are fed by a common distributing launder
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and can be connected with one another by pivoting conveyors,
and which have a common downstream rolling train.
Figure 4b is a perspective view of the installation
according to Figure 4b.
Detailed Description of the Specific Embodiments
Figure la shows a specific embodiment of an installation
of the invention with two CSP installations 2 or vertical
thin-slab casting installations 2. These vertical thin-slab
casting installations 2 in themselves are already well known.
In these installations 2, a strand is first vertically cast
with a mold 4 and then bent by a bending device 7 and
subsequently straightened with a straightening unit.
Optionally, a cutting unit 8 or shears 8 are provided farther
along in the direction of casting. The slabs then arrive in a
downstream temperature-adjusting unit 9, especially a furnace
9, where, for example, they can be heated or held at a certain
temperature.
A horizontal thin-slab casting installation 1 is arranged
alongside the two CSP casting installations 2. This
installation is preferably located parallel next to one of the
vertical thin-slab casting installations 2. The installation
1, which is shown at the top in Figure la, has a charging
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vessel 5 for the melt and a conveyor belt 6, onto which the
liquid metal is guided and on which the metal strip begins to
solidify. This is followed downstream in Figure la by a
temperature-adjusting zone or unit 9.
The embodiment illustrated in Figure 1 is also provided
with pivoting conveyors 10 for conveying the slabs from the
end of the two outer casting lines to the casting line
arranged in the middle. Experts in this field are already
familiar with the design of pivoting conveyors 10.
Alternatively, parallel conveyors, which in themselves are
already well known, can be provided in accordance with the
invention. Optionally, the temperature-adjusting zones 9 can
be designed as roller hearth furnaces; in particular, the
conveyors 10 are designed as (tunnel) furnace conveyors.
Suitable use of the conveyors 10 allows slabs to be conveyed
from each of the three installations 1, 2 to a downstream
rolling train 11. In particular, as shown in the drawings, a
total of three casting lines or installations 1, 2 are
arranged side by side. The rolling train 11 is preferably
located in line with the middle of the three casting lines.
The slabs produced by the outer lines can then be conveyed by
the conveyors 10 into a section of the temperature-adjusting
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unit 9 that is in line with the rolling train 11. In general,
for one or more of the casting lines, it is also possible to
charge slabs from the outside into one of the casting lines.
Furthermore, an additional roughing stand can also be provided
in one of the casting lines for rolling slabs thus charged.
The design of the rolling train 11 arranged downstream of the
casting installations 1, 2, which preferably comprises several
roll stands 12, is not the focus of the invention and can thus
be of any known type.
Figure lb shows the installation according to Figure la,
wherein the molds 4 of the vertical thin-slab casting and
rolling installation are supplied with melt by a common
distributing launder.
The installation according to Figures la and lb makes it
possible to combine the advantages of horizontal thin-slab
casting installations 1 with those of vertical thin-slab
casting installations 2. The rolling train 11 is fully
utilized, since three casting lines supply one rolling train
11. If a thin-slab casting installation 1 were provided by
itself, the investment for the rolling train 11, measured by
the amount produced by the thin-slab casting plant 1, would be
relatively high. If a vertical thin-slab casting installation
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2 is already present in a plant, it can be expanded by a
horizontal thin-slab casting installation in accordance with
the invention, so that the economy of the rolling train 11
that is already present is increased, and the production
spectrum is expanded.
Figures is and id show an embodiment of an installation
according to the invention that is similar to the embodiment
of Figures la and lb, but in contrast to the installation
shown in Figures la and lb, the horizontal thin-slab casting
installation 1 (shown at the top in Figures lb and lc) is
realized with a shorter temperature-adjusting unit 9.
Installations of this type can also be operated more
efficiently now, although they have only a relatively short
temperature-adjusting zone 9 for the temporary storage of the
thin or very thin slabs. The rest of the system is equivalent
to the system shown in Figures la and lb.
Figure 2a shows a vertical thin-slab casting installation
2 with a downstream rolling train 11 arranged in line with it.
Horizontal thin-slab installations 1 of the type already shown
in Figures lb and lc are arranged next to this installation.
As in the case of the specific embodiments described earlier,
slabs can be conveyed or guided by means of conveyors 10 from
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the two outer thin-slab casting installations 1 or casting
lines, preferably from the end of the given temperature-
adjusting unit 9, into a section of the temperature-adjusting
zone 9 of the middle casting line or thin-slab casting
installation 2. As seen in the casting direction, this
section is preferably positioned in a middle region of the
temperature-adjusting unit 9 of the vertical thin-slab casting
installation 2. If slabs arrive in this section from the
outer casting lines, they preferably still pass through part
of the temperature-adjusting zone 9 and are then fed to the
rolling train 11.
Figure 2b shows the same system as Figure 2a but in a
perspective view. The reference numbers refer to the same
structures as in Figures la to ld.
Figures 3a and 3b show a top view and a perspective view
of another embodiment of an installation according to the
invention. In this embodiment, three horizontal thin-slab
casting installations 1 are arranged side by side, and a
downstream rolling train 11 is aligned with or is arranged in
line with the thin-slab casting installation 1 that is
arranged in the middle of the three installations. As in the
previous embodiments, a conveyor system 10 is provided for
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conveying slabs from the outer installations to the
installation or casting line that is arranged in the middle.
Figures 4a and 4b are analogous to Figures 3a and 3b, but
all of the casting lines are supplied with melt by a common
distributing launder 3. In this case, we can also talk of an
installation with three or more strands feeding one rolling
train 11.
In general, features from all of the figures can be
combined with one another, or individual design details can be
adapted by the expert to the specific application.
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List of Reference Numbers
1 horizontal thin-slab casting installation
2 vertical thin-slab casting installation
3 distributing launder
4 mold
charging vessel
6 conveyor belt
7 bending device / straightening device
8 cutting device
9 temperature-adjusting unit
pivoting conveyor
11 rolling train
12 roll stand
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