U.S. patent application number 10/285734 was filed with the patent office on 2003-03-20 for method and plant for the hot rolling of strip.
Invention is credited to Kramer, Stephan.
Application Number | 20030051525 10/285734 |
Document ID | / |
Family ID | 7781684 |
Filed Date | 2003-03-20 |
United States Patent
Application |
20030051525 |
Kind Code |
A1 |
Kramer, Stephan |
March 20, 2003 |
Method and plant for the hot rolling of strip
Abstract
A method and a plant for the hot rolling of strip, in which the
rolling stock is rolled in at least one reversing roughing stand
with a number of roughing passes into a broken-down strip, and the
broken-down strip is transported over an intermediate roller table
into at least one Steckel finishing stand and the strip is
finish-rolled in the finishing stand with a number of passes into a
finished strip having a predetermined thickness, and the strip is
finally wound into a coil. The length of the intermediate roller
table determined by the length of the broken-down strip is
shortened and tandem rolling is carried out in the roughing stand
and the finishing stand at least during the last breaking-down pass
of the strip.
Inventors: |
Kramer, Stephan;
(Hilchenbach, DE) |
Correspondence
Address: |
Friedrich Kueffner
Suite 910
317 Madison Avenue
New York
NY
10017
US
|
Family ID: |
7781684 |
Appl. No.: |
10/285734 |
Filed: |
November 1, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10285734 |
Nov 1, 2002 |
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08771296 |
Dec 20, 1996 |
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Current U.S.
Class: |
72/229 |
Current CPC
Class: |
B21B 1/26 20130101; B21B
1/34 20130101; B21B 37/52 20130101 |
Class at
Publication: |
72/229 |
International
Class: |
B21B 041/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 30, 1995 |
DE |
195 49 208.0 |
Claims
I claim:
1. In a method of hot-rolling of strip from rolling stock,
including rolling the rolling stock in at least one reversing
roughing stand with a number of passes into a broken-down strip
having a length, transporting the broken-down strip over an
intermediate roller table into at least one Steckel finishing stand
and finish-rolling the broken-down strip in the Steckel finishing
stand with a number of passes into a finished strip, and finally
winding the strip into a coil, the improvement comprising
shortening a length of the intermediate roller table determined by
the length of the broken-down strip, and carrying out tandem
rolling in the roughing stand and the finishing stand at least
during a last roughing pass.
2. The method according to claim 1, comprising shortening the
length of the intermediate roller table to a length which is
shorter than the length of the broken-down strip.
3. The method according to claim 1, wherein the length of the
intermediate roller is shortened to such an extent that tandem
rolling of the broken-down strip in the roughing stand and the
finishing stand can be carried out already during a second to last
roughing pass.
4. The method according to claim 1, wherein rolling speeds of the
roughing stand and the finishing stand are synchronized during
tandem rolling.
5. The method according to claim 4, wherein during tandem rolling a
transport speed and a transport direction of the intermediate
roller table are synchronized with the rolling speed and the
rolling direction of the roughing stand and the finishing
stand.
6. A plant for the hot rolling of strip, comprising at least one
reversing roughing stand for breaking-down rolling of a strip into
a broken-down strip and at least one Steckel finishing stand for
reducing the broken-down strip to a finished strip, further
comprising an intermediate roller table connecting the roughing
stand and the finishing stand, wherein a length of the intermediate
roller table corresponds at most to a length of the broken-down
strip prior to one of last roughing passes.
7. The plant according to claim 6, comprising shears upstream of
the finishing stand, wherein the length of the intermediate roller
table corresponds approximately to a distance between the finishing
stand and the shears.
8. The plant according to claim 6, wherein the length of the
intermediate roller table corresponds approximately to a length of
the broken-down strip prior to the last roughing pass.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method and a plant for
the hot rolling of strip, in which the rolling stock is rolled in
at least one reversing roughing stand with a number of roughing
passes into a broken-down strip, and the broken-down strip is
transported over an intermediate roller table into at least one
Steckel finishing stand and the strip is finish-rolled in the
finishing stand with a number of passes into a finished strip
having a predetermined thickness, and the strip is finally wound
into a coil.
[0003] 2. Description of the Related Art
[0004] In a method and a plant for carrying out the method in the
prior art, it is conventional to select the length of the roller
table between the roughing stand and the Steckel finishing stand in
such a way that, after emerging from the roughing stand, the
broken-down strip rests "freely" between the roughing stand and the
cropping shears. Accordingly, the length of the roller table is
essentially determined by the length of the broken-down strip.
[0005] This results in the disadvantage that either the length of
the broken-down strip, and thus, the predetermined charge weight of
the product are limited, or that the plant requires a relatively
large space, wherein, in that case, there is the additional
disadvantage that the broken-down strip enters the Steckel
finishing stand with a low temperature because of the heat loss
occurring on the relatively long transport path between roughing
stand and Steckel finishing stand. The increased load in the
finishing stand caused by the lower temperature of the strip has a
disadvantageous effect on the finish-rolling process, wherein
additionally smaller reductions are achieved in each pass.
SUMMARY OF THE INVENTION
[0006] Therefore, it is the primary object of the present invention
to provide a method and a plant for the hot rolling of strip of the
type described above in which the disadvantages discussed above are
avoided and hot rolling can be carried out with the use of
uncomplicated measures and means.
[0007] In accordance with the present invention, in the method of
the type described above, the length of the intermediate roller
table determined by the length of the broken-down strip is
shortened and tandem rolling is carried out in the roughing stand
and the finishing stand at least during the last breaking-down pass
of the strip.
[0008] The possibility of shortening the roller table is
advantageously provided in accordance with the present invention by
dropping the requirement for a "free" runout of the broken-down
strip following one of the last roughing passes or following the
last roughing pass, and by instead carrying out tandem rolling by
the roughing stand and the finishing stand, wherein the rolling
speeds of the stands are synchronized.
[0009] In addition to shortening the roller table, and, thus, a
corresponding linear shortening of the total length of the plant
and decreased investment and operating costs, the present invention
further provides the significant advantage that the broken-down
strip has a higher temperature when it enters the Steckel finishing
stand. This has a positive effect on finish-rolling and, for
example, facilitates lower loads in the finishing stand and
produces greater reductions.
[0010] The plant for the hot rolling of strip according to the
present invention includes at least one reversing breaking-down
stand for breaking down the strip and at least one Steckel
finishing stand for reducing the broken-down strip to finished
strip, wherein the roughing stand and the finishing stand are
connected to each other through a roller table whose length is
determined by the length of the broken-down strip. The plant is
intended especially for carrying out the above-described method
according to the present invention and is characterized in that the
length of the roller table corresponds at most to the length of the
broken-down strip prior to one of the last breaking-down
passes.
[0011] The length of the roller table may approximately correspond
to the distance between the roughing stand and the shears.
[0012] The various features of novelty which characterize the
invention are pointed out with particularity in the claims annexed
to and forming a part of the disclosure. For a better understanding
of the invention, its operating advantages, specific objects
attained by its use, reference should be had to the drawing and
descriptive manner in which there are illustrated and described
preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWING
[0013] In the drawing:
[0014] FIG. 1 is a schematic illustration of a conventional plant
for the hot rolling of strip; and
[0015] FIG. 2 is a schematic illustration of a plant for the hot
rolling of strip according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] FIG. 1 of the drawing shows a prior art embodiment of a
plant for the hot-rolling of strip which includes at least one
reversing roughing stand 1 for breaking-down rolling of a strip 10
and at least one Steckel finishing stand 3 for reducing the
broken-down strip 10 into finished strip. Both plant components,
i.e., roughing stand 1 and finishing stand 3, are connected to each
other through an intermediate roller table 2.
[0017] As shown in FIG. 1, in the conventional plant, the length of
the intermediate table 2 is selected in such a way that, after
emerging from the roughing stand 1 which may be the last roughing
stand of a sequence of roughing stands, the broken-down strip 10 is
placed freely between the roughing stand 1 and the cropping shears
4. This means that the length of the intermediate roller table 2 is
determined essentially by the length of the broken-down strip.
[0018] Solutions with intermediate storage units or coil boxes,
which are usually used in tandem rolling trains for hot strip and
facilitate shortening of the distance between the roughing stand
and the finishing train, have not become known in the past in
Steckel rolling trains. As shown in FIG. 1, the broken-down strip
has the length L.sub.1 which corresponds to the distance between
roughing stand 1 and cropping shears 4 and which is substantially
shorter than the distance A.sub.1 between the roughing stand 1 and
the finishing stand 3. As it is known in the art, the finishing
stand 3 includes reeling furnaces 5 and 6.
[0019] An embodiment of the plant according to the present
invention is shown in FIG. 2. In that embodiment, the length
A.sub.2 of the intermediate roller table 2 is at most equal to the
length L.sub.2 of the broken-down strip 10 prior to the roughing
pass n-1, wherein n is the number of passes in the roughing
stand.
[0020] In the following, the invention will be explained in more
detail with the aid of an example.
EXAMPLE
[0021] The following parameters are given:
[0022] Weight: 18 kg/mm
[0023] Thickness of broken-down strip: 25 mm
[0024] Length of broken-down strip: 94.74 mm
[0025] In the conventional plant according to FIG. 1, the distance
between the roughing stand 1 and the finishing stand 3 is
approximately 120 m, wherein the number of passes in the roughing
stand 1 is n. The broken-down strip 10 just rolls out freely onto
the intermediate roller table 2 between the roughing stand 1 and
the cropping shears 4.
[0026] In accordance with the present invention as illustrated in
FIG. 2, when the roller table is shortened to a length A.sub.2 in
accordance with a broken-down strip length during pass n-2, tandem
rolling in roughing stand 1 and finishing stand 3 takes place
because the strip 10 having the length L.sub.2 is longer than the
distance A.sub.2 between the roughing stand 1 and the finishing
stand 3.
[0027] Coil weight: 18 kg/mm
[0028] Thickness of broken-down strip (n-2): 25
mm.times.1/0.75.times.1/0.- 75=44.44 mm (assuming a reduction of
25% each in the last two roughing passes)
[0029] Length of broken-down strip (n-2): 53.29 mm
[0030] Consequently, the required length of the intermediate roller
table 2 can be reduced by 94.74 m-53.29 m=41.45 m.
[0031] As explained above, in addition to shortening the length of
the intermediate roller table, the present invention provides the
advantage of an increased temperature of the broken-down strip
which has positive effects on finish-rolling.
[0032] In accordance with the method of the present invention,
during tandem rolling, the rolling speeds of roughing stand 1 and
finishing stand 3 are synchronized.
[0033] In addition, it is possible during tandem rolling to
synchronize the transport speed and the transport direction of the
intermediate roller table with the rolling speed and the rolling
direction of the roughing stand 1 and the finishing stand 3.
[0034] While specific embodiments of the invention have been shown
and described in detail to illustrate the inventive principles, it
will be understood that the invention may be embodied otherwise
without departing from such principles.
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