U.S. patent application number 15/578520 was filed with the patent office on 2018-06-14 for continuous casting and rolling method and continuous casting and rolling apparatus.
The applicant listed for this patent is POSCO. Invention is credited to Yong-Seok CHO, Jea-Sook CHUNG, Young-Ju KO, Kyeong-Mi PARK, Young-Sup SHIM, Suk-Cheol SONG.
Application Number | 20180161837 15/578520 |
Document ID | / |
Family ID | 57440664 |
Filed Date | 2018-06-14 |
United States Patent
Application |
20180161837 |
Kind Code |
A1 |
KO; Young-Ju ; et
al. |
June 14, 2018 |
CONTINUOUS CASTING AND ROLLING METHOD AND CONTINUOUS CASTING AND
ROLLING APPARATUS
Abstract
Provided is a continuous casting and rolling method, which
includes: a continuous casting operation of producing a slab; and a
rolling operation of pressing the slab after a front end portion of
the slab passes a first rolling stand into which the front end
portion of the slab, which is provided as a continuous body to the
slab produced in the continuous casting operation, initially
enters.
Inventors: |
KO; Young-Ju; (Gwangyang-si,
KR) ; CHUNG; Jea-Sook; (Gwangyang-si, KR) ;
SONG; Suk-Cheol; (Gwangyang-si, KR) ; PARK;
Kyeong-Mi; (Gwangyang-si, KR) ; CHO; Yong-Seok;
(Gwangyang-si, KR) ; SHIM; Young-Sup;
(Gwangyang-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
POSCO |
Pohang-si |
|
KR |
|
|
Family ID: |
57440664 |
Appl. No.: |
15/578520 |
Filed: |
September 18, 2015 |
PCT Filed: |
September 18, 2015 |
PCT NO: |
PCT/KR2015/009839 |
371 Date: |
November 30, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21B 1/463 20130101;
B21B 1/02 20130101; B21B 35/02 20130101; B21B 1/46 20130101; B21B
38/00 20130101; B21B 2001/028 20130101 |
International
Class: |
B21B 1/46 20060101
B21B001/46; B21B 35/02 20060101 B21B035/02; B21B 38/00 20060101
B21B038/00; B21B 1/02 20060101 B21B001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2015 |
KR |
10-2015-0078578 |
Claims
1. A continuous casting and rolling method, comprising: a
continuous casting operation of producing a slab; and a rolling
operation of reducing the slab after a front end portion of the
slab passes a first rolling stand into which the front end portion
of the slab, which is provided as a continuous body with the slab
produced in the continuous casting operation, initially enters.
2. The continuous casting and rolling method of claim 1, wherein,
in the rolling operation, the slab is reduced, after the front end
portion of the slab passes a rolling mill, a group of a plurality
of rolling stands including the first rolling stand.
3. The continuous casting and rolling method of claim 1, wherein
the rolling operation includes: an inputting operation of passing
the front end portion of the slab through the first rolling stand,
which is open; a supporting operation of allowing a pair of rolling
rolls, provided in the first rolling stand after the front end
portion of the slab passes the first rolling stand, to be in close
contact with the slab; and a reducing operation of reducing the
slab with the second rolling stand, when the front end portion of
the slab enters a second rolling stand provided after the first
rolling stand.
4. The continuous casting and rolling method of claim 1, wherein
the rolling operation includes: an inputting operation of passing
the front end portion of the slab through the first rolling stand,
which is open; a reducing operation of reducing the slab with the
second rolling stand, when the front end portion of the slab enters
a second rolling stand provided after the first rolling stand; and
a buffering operation of moving a pair of rolling rolls provided in
the first rolling stand upwardly or downwardly, or moving a pair of
pinch rolls provided in an inlet of the first rolling stand
upwardly or downwardly, when a portion of the slab, having been
reduced, moves backwards to the first rolling stand.
5. The continuous casting and rolling method of claim 1, wherein,
in the rolling operation, a pair of rolling rolls, provided in each
of a plurality of rolling stands including the first rolling stand,
sequentially roll the slab while a distance is gradually reduced in
a direction of progress of the slab.
6. A continuous casting and rolling apparatus, comprising: a
continuous caster for producing a slab; and a rolling mill located
at an outlet of the continuous caster, and having a plurality of
rolling stands including a first rolling stand into which a front
end portion of the slab, which is provided as a continuous body
with the slab produced in the continuous caster, initially enters,
wherein the rolling mill is provided to reduce the slab after the
front end portion of the slab passes the first rolling stand.
7. The continuous casting and rolling apparatus of claim 6, wherein
the rolling mill includes: a support point determining sensor
provided at an outlet of the first rolling stand, and sensing the
front end portion of the slab; and a reducing point determining
sensor provided in an inlet of a second rolling stand provided
after the first rolling stand, and sensing the front end portion of
the slab.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a continuous casting and
rolling method and to a continuous casting and rolling apparatus,
and more particularly, to an invention for preventing a problem in
which a slab moves backwards during a process of performing
continuous casting and rolling.
BACKGROUND ART
[0002] A process of performing rolling using a high temperature
slab solidified in a continuous caster is widely used at present,
because equipment costs and operating costs are lower than a
process according to the related art.
[0003] In addition, while continuous casting and rolling are
continuously undertaken, it is also possible to carry out a
discontinuous process in which rolling can be carried out
separately from the continuous casting, described in Korean Patent
Application Laid-open Publication No. 1990-7001437, in detail.
[0004] In other words, each of a continuous rolling mode, in which
a continuous casting process and a rolling process are continuously
performed, and a discontinuous rolling mode, in which the
continuous casting process and the rolling process are
discontinuously performed, may be carried out.
[0005] Here, FIG. 1 illustrates an apparatus 1' capable of
performing continuous rolling. When a slab 2', having a constant
thickness, is produced in a continuous caster 10', the slab 2' is
rolled in a rolling mill 20'. Additionally, the slab 2' is heated
by a heater 40' and is then rolled. The slab 2', in which rolling
is finished, is cut by a cutter 30' and wound by a winder, so that
a product is produced therefrom.
[0006] However, here, when a front end portion of the slab 2'
preceding the slab 2', discharged from the continuous caster 10',
is input into the rolling mill 20' and is reduced, the front end
portion of the slab 2' is input and reduced without tension, so a
problem in which backward force in a direction of the continuous
caster 10' may occur.
[0007] This backward force may affect a level of a surface of
molten steel in the continuous caster 10', and may affects the
entirety of equipment, so there may be limitations in securing
product quality.
[0008] Thus, there has been a need for research into a continuous
casting and rolling method and a continuous casting and rolling
apparatus able to solve the above-mentioned problem.
DISCLOSURE
Technical Problem
[0009] An aspect of the present disclosure may provide a continuous
casting and rolling method and a continuous casting and rolling
apparatus, capable of preventing a problem in which a slab moves
backwards when a front end portion of the slab, produced in a
continuous caster, is input into a rolling mill.
Technical Solution
[0010] According to an aspect of the present disclosure, a
continuous casting and rolling method includes: a continuous
casting operation of producing a slab; and a rolling operation of
reducing the slab after a front end portion of the slab passes a
first rolling stand into which the front end portion of the slab,
which is provided as a continuous body with the slab produced in
the continuous casting operation, initially enters.
[0011] In the rolling operation, the slab is reduced, after the
front end portion of the slab passes a rolling mill, a group of a
plurality of rolling stands including the first rolling stand.
[0012] The rolling operation includes: an inputting operation of
passing the front end portion of the slab through the first rolling
stand, which is open; a supporting operation of allowing a pair of
rolling rolls, provided in the first rolling stand after the front
end portion of the slab passes the first rolling stand, to be in
close contact with the slab; and a reducing operation of reducing
the slab with the second rolling stand, when the front end portion
of the slab enters a second rolling stand provided after the first
rolling stand.
[0013] The rolling operation includes: an inputting operation of
passing the front end portion of the slab through the first rolling
stand, which is open; a reducing operation of reducing the slab
with the second rolling stand, when the front end portion of the
slab enters a second rolling stand provided after the first rolling
stand; and a buffering operation of moving a pair of rolling rolls
provided in the first rolling stand upwardly or downwardly, or
moving a pair of pinch rolls provided in an inlet of the first
rolling stand upwardly or downwardly, when a portion of the slab,
having been reduced, moves backwards to the first rolling
stand.
[0014] In the rolling operation, a pair of rolling rolls, provided
in each of a plurality of rolling stands including the first
rolling stand, sequentially roll the slab while a distance is
gradually reduced in a direction of progress of the slab.
[0015] A continuous casting and rolling apparatus includes: a
continuous caster for producing a slab; and a rolling mill located
at an outlet of the continuous caster, and having a plurality of
rolling stands including a first rolling stand into which a front
end portion of the slab, provided as a continuous body with the
slab produced in the continuous caster, initially enters, wherein
the rolling mill is provided to reduce the slab after the front end
portion of the slab passes the first rolling stand.
[0016] The rolling mill includes: a support point determining
sensor provided at an outlet of the first rolling stand, and
sensing the front end portion of the slab; and a reducing point
determining sensor provided in an inlet of a second rolling stand
provided after the first rolling stand, and sensing the front end
portion of the slab.
Advantageous Effects
[0017] According to an exemplary embodiment in the present
disclosure, in a continuous casting and rolling method and a
continuous casting and rolling apparatus, when a front end portion
of a slab is rolled, the slab may be prevented from moving
backwards.
[0018] Thus, there is an advantage that a level of a surface of
molten steel in a continuous caster may be stabilized and an
influence on other apparatuses may be prevented.
[0019] Thus, continuity in a process of continuous casting and
rolling may be ensured, and a quality of a rolled product to be
produced may be improved.
DESCRIPTION OF DRAWINGS
[0020] FIG. 1 is a view illustrating a continuous casting and
rolling apparatus according to the related art.
[0021] FIG. 2 is a side view illustrating a continuous casting and
rolling apparatus according to an exemplary embodiment.
[0022] FIG. 3 is a side view illustrating an example of a case in
which a front end portion of a slab is input into a rolling mill in
a continuous casting and rolling apparatus according to an
exemplary embodiment.
[0023] FIG. 4 is a side view illustrating another example of a case
in which a front end portion of a slab is input into a rolling mill
in a continuous casting and rolling apparatus according to an
exemplary embodiment.
[0024] FIG. 5 is a flow diagram illustrating a continuous casting
and rolling method according to an exemplary embodiment.
[0025] FIG. 6 is a flow diagram illustrating one example of a
rolling operation in a continuous casting and rolling method
according to an exemplary embodiment.
[0026] FIG. 7 is a flow diagram illustrating another example of a
rolling operation in a continuous casting and rolling method
according to an exemplary embodiment.
BEST MODE FOR INVENTION
[0027] Hereinafter, exemplary embodiments of the present invention
will be described in detail with reference to the accompanying
drawings. Meanwhile, the spirit of the present invention is not
limited to the suggested embodiments, and those skilled in the art
to which the present invention pertains could easily suggest a
further retrogressive invention or another embodiment which falls
within the spirit of the present invention through the addition,
modification, and deletion of another component without departing
from the spirit of the present invention.
[0028] In the following description, components having the same
function within the same scope illustrated in the drawings of the
embodiments are illustrated using the same reference numerals.
[0029] A continuous casting and rolling method and a continuous
casting and rolling apparatus 1 according to an exemplary
embodiment relate to the invention for preventing a problem in
which a slab 2 moves backwards during a process of performing
continuous casting and rolling.
[0030] In other words, according to the continuous casting and
rolling method and the continuous casting and rolling apparatus 1
according to an exemplary embodiment, when a front end portion 2a
of the slab 2 is rolled, the slab 2 is prevented from moving
backwards, so a level of molten metal of a continuous caster 10 is
stabilized and an effect on other devices is prevented. Thus,
continuity of a process for continuous casting and rolling may be
ensured and a quality of a rolled product having been produced may
be improved.
[0031] In detail, FIG. 2 is a side view illustrating a continuous
casting and rolling apparatus 1 according to an exemplary
embodiment. Referring thereto, a continuous casting and rolling
apparatus 1 according to another exemplary embodiment includes a
continuous caster 10 of producing a slab 2, and a rolling mill 20
located at an outlet of the continuous caster 10, and having a
plurality of rolling stands including a first rolling stand 21 into
which a front end portion 2a of the slab 2, which is provided as a
continuous body with the slab 2 produced in the continuous caster
10, initially enters. The rolling mill 20 may be provided to reduce
the slab 2 after the front end portion 2a of the slab 2 passes the
first rolling stand 21.
[0032] In addition, the rolling mill 20 of the continuous casting
and rolling apparatus 1 according to another exemplary embodiment
may include a support point determining sensor 23 provided at an
outlet of the first rolling stand 21, and sensing the front end
portion 2a of the slab 2, and a reducing point determining sensor
24 provided in an inlet of a second rolling stand 22 provided after
the first rolling stand 21, and sensing the front end portion 2a of
the slab 2.
[0033] In other words, as a configuration for solving a problem, in
which backward force is generated while a thickness of the slab 2
is reduced, when the front end portion 2a of the slab 2 is reduced,
the continuous caster 10, the rolling mill 20, and the like are
proposed.
[0034] The continuous caster 10 may serve to produce the slab 2
from molten steel through a casting process. In other words, the
continuous caster 10 supplies molten steel from a tundish to a
mold, and the slab 2 is formed from the molten steel, having been
supplied, while a certain amount of heat is removed therefrom. The
slab 2 is guided by a segment roll and a pinch roll, moves, and is
supplied to the rolling mill 20, which will be described later.
[0035] However, as the continuous caster 10 produces the slab 2,
depending on a solidification rate of the molten steel, there may
be limitations in controlling a production speed. In this case,
producing a product by continuously receiving the slab 2 produced
in the continuous caster 10 and reducing the slab using the rolling
mill 20 which will be described later is limited in terms of
speed.
[0036] However, as an average temperature of the slab 2 discharged
from the continuous caster 10 is high, there is an advantage in
which a temperature required during a rolling operation in the
rolling mill 20 may be secured, to a certain extent.
[0037] The rolling mill 20 may serve to produce a rolled steel
sheet by receiving the slab 2 produced in the continuous caster 10
and reducing the slab. To this end, the rolling mill 20 may allow
the slab 2 to pass between a pair of rolling rolls and to be
reduced, and a rolling stand to which the pair of rolling rolls are
provided may be provided in plural.
[0038] Here, when the slab 2 produced in the continuous caster 10
is continuously received, and reducing is performed by the rolling
mill 20, while tension is not maintained, of the front end portion
2a of the slab 2 is input into the first rolling stand 21, an
initial rolling stand, so backward force causing the slab to move
toward the continuous caster 10 may be generated.
[0039] In other words, when the slab 2 is reduced, while a
thickness of the slab 2 is reduced, a length is increased. An
elongated portion is provided while a length is increased in a
direction of progress of the slab 2. However, an elongated portion
may be provided while a length is increased in an opposite
direction to the direction of progress of the slab 2, so a problem
in which backward force causing the slab 2 to move toward the
continuous caster 10 may occur.
[0040] In order to solve the problem described above, in an
exemplary embodiment, after the front end portion 2a of the slab 2
passes the first rolling stand 21, reducing with respect to the
slab 2 is performed, so backward force may be prevented from being
exerted on the slab 2.
[0041] In other words, the slab 2 passing the first rolling stand
21 is pushed by other rolling stands such as the second rolling
stand 22 provided after the first rolling stand 21, and the like.
Thus, when the front end portion 2a of the slab 2 in which tension
is not maintained is reduced, a portion of the slab 2, located
after the front end portion 2a, supports that the slab 2 is pushed
backwards.
[0042] In other words, a portion of the front end portion 2a of the
slab 2, a free end which is not fixed, moves forward in a direction
of progress of the slab 2 in order to accommodate a portion in
which a length is increased due to reducing, and portions located
after the front end portion 2a of the slab 2 reduced and held by
the rolling stands, functioning as a fixed end, may not accommodate
a portion of the slab 2, in which a length is increased, but may
support that the slab 2 is pushed backwards.
[0043] Moreover, the rolling mill 20 includes the support point
determining sensor 23, the reducing point determining sensor 24,
and the like, thereby further increasing efficiency of preventing
backward force from being generated when the front end portion 2a
of the slab 2 is reduced.
[0044] In other words, so that the first rolling stand 21 is
provided to perform only a role of supporting that the slab 2 moves
backwards, in addition to a role of reducing, for a period of time,
the first rolling stand includes the support point determining
sensor 23 and the reducing point determining sensor 24.
[0045] In other words, it is advantageous to perform reducing with
respect to the slab 2 at a point as early as possible in order to
improve yield percentage. In this regard, in order to perform a
reducing operation from a point in which the front end portion 2a
of the slab 2 is input into the second rolling stand 22, the
support point determining sensor 23 and the reducing point
determining sensor 24 are included.
[0046] The support point determining sensor 23 is a sensor,
provided at an outlet of the first rolling stand 21, discharging
the slab 2 from the first rolling stand 21, and sensing a point at
which the front end portion 2a of the slab 2 passes the first
rolling stand 21.
[0047] Here, when the support point determining sensor 23 senses
the front end portion 2a of the slab 2, a pair of rolling rolls 21a
provided in the first rolling stand 21 are provided to be in close
contact with the slab 2, thereby preventing the slab 2 from being
pushed backwards.
[0048] Thereafter, when the reducing point determining sensor 24
senses the front end portion 2a of the slab 2, reducing is
performed and a rolling operation is then performed.
[0049] The reducing point determining sensor 24 is a sensor,
provided in an inlet of the second rolling stand 22, in which the
slab 2 enters the second rolling stand 22, and sensing a point in
which the front end portion 2a of the slab 2 enters the second
rolling stand 22.
[0050] Here, when the reducing point determining sensor 24 senses
the front end portion 2a of the slab 2, the second rolling stand 22
allows the slab 2 to be reduced, thereby performing a rolling
operation.
[0051] In detail, in this case, the first rolling stand 21 is in
close contact with the slab 2 to support that the slab 2 is pushed
backwards. Thus, a portion of the slab 2, in which a length is
increased when the slab is reduced in the second rolling stand 22,
is provided to move forward without being pushed backwards.
[0052] In addition, the continuous casting and rolling apparatus 1
according to an exemplary embodiment may further include a cutter
30, a heater 40, and the like, and a continuous casting and rolling
process may be performed.
[0053] Here, the heater 40 serves to heat the slab 2 when a
temperature of the slab 2 does not reach a temperature for rolling,
before the slab 2, produced and provided in the continuous caster
10, is supplied to the rolling mill 20.
[0054] The cutter 30 may serve to cut the slab 2, or may be
provided to cut the slab 2 as needed in a middle portion of the
continuous casting and rolling apparatus 1, in order to discharge a
product finished by reducing the slab 2.
[0055] FIG. 5 is a flow diagram illustrating a continuous casting
and rolling method according to an exemplary embodiment. Referring
to this, a continuous casting and rolling method according to an
exemplary embodiment may include a continuous casting operation of
producing the slab 2, and a rolling operation or reducing the slab
2 after the front end portion 2a of the slab 2 passes the first
rolling stand 21 into which the front end portion 2a of the slab 2,
which is provided as a continuous body with the slab 2 produced in
the continuous casting operation, initially enters.
[0056] In addition, in the rolling operation of the continuous
casting and rolling method according to an exemplary embodiment,
the rolling mill 20, a group of a plurality of rolling stands
including the first rolling stand 21 allows the slab 2 to be
reduced, after the front end portion 2a of the slab 2 passes.
[0057] In addition, in the rolling operation of the continuous
casting and rolling method according to an exemplary embodiment, a
pair of rolling rolls, provided in each of a plurality of rolling
stands, including the first rolling stand 21, allow the slab 2 to
be sequentially rolled, while a distance is gradually reduced in a
direction of progress of the slab 2.
[0058] In other words, when the front end portion 2a of the slab 2
is reduced, in order to prevent a problem in which backward force
is generated while a thickness of the slab 2 is reduced is
prevented from occurring, a continuous casting operation and a
rolling operation are proposed.
[0059] The continuous casting operation is an operation of
producing the slab 2 by the continuous caster 10, and molten steel
is received and the slab 2 is formed by continuous casting. In this
case, the rolling operation is performed as the front end portion
2a of the slab 2, generated at the beginning of the continuous
casting operation, is input into the rolling mill 20.
[0060] The rolling operation is an operation of producing a rolled
steel sheet product by receiving the slab 2 produced in the
continuous casting operation and reducing the slab.
[0061] Here, at the beginning of performing reducing with respect
to the slab 2, as the front end portion 2a of the slab 2 is input
into the first rolling stand, an initial rolling stand, while
tension is not maintained, a problem in which backward force,
causing the slab to move toward the continuous caster, is
generated, is described previously.
[0062] In an exemplary embodiment, in order to solve the problem
described above, in the rolling operation, after the front end
portion 2a of the slab 2 passes through the first rolling stand 21,
reducing with respect to the slab 2 is performed, in order to
prevent backward force of the slab 2 from being generated.
[0063] In other words, the slab 2 passing through the first rolling
stand 21 is pushed by other rolling stands such as the second
rolling stand 22 provided after the first rolling stand 21, and the
like. Thus, when the front end portion 2a of the slab 2 in which
tension is not maintained is reduced, while a portion of the slab
2, located after the front end portion 2a, supports that the slab 2
is pushed backwards, a rolling operation is performed.
[0064] In this regard, the rolling operation is performed so that a
portion of the front end portion 2a of the slab 2, a free end which
is not fixed, moves forward in a direction of progress of the slab
2 in order to accommodate a portion in which a length is increased
due to reducing, and portions located after the front end portion
2a of the slab 2 pushed by the rolling stands function as a fixed
end to support a portion of the slab 2 in which a length is
increased.
[0065] Moreover, when reducing with respect to the slab 2 is
performed after the front end portion 2a of the slab 2 is
discharged from the rolling mill 20, while reducing with respect to
the front end portion 2a of the slab 2 is not performed, only
reducing with respect to a portion located after the front end
portion 2a of the slab 2 is performed. Thus, reducing is performed
with respect to the slab 2 while tension is maintained, so a
problem in which the slab 2 is pushed backwards due to reducing may
be prevented.
[0066] In addition, sequential rolling with respect to the front
end portion 2a of the slab 2 is performed. Thus, when the slab 2 is
reduced, backward force may be prevented from occurring in the slab
2.
[0067] In other words, in a plurality of rolling stands included in
the rolling mill 20, a distance between a pair of rolling rolls is
provided to be gradually reduced in a direction of progress of the
slab 2. Thus, sequential rolling is performed with respect to the
slab 2, so the slab 2 maybe prevented from moving backwards.
[0068] (a) through (d) of FIG. 3 are side views illustrating one
example of a case in which the front end portion 2a of the slab 2
is input into the rolling mill 20 in the continuous casting and
rolling apparatus 1 according to an exemplary embodiment, and FIG.
6 is a flow diagram illustrating one example of a rolling operation
in a continuous casting and rolling method according to an
exemplary embodiment.
[0069] Here, (a) of FIG. 3 illustrates a state before the front end
portion 2a of the slab 2 enters the rolling mill 20, (b) of FIG. 3
illustrates an inputting operation, a state in which the front end
portion 2a of the slab 2 enters the first rolling stand 21, (c) of
FIG. 3 illustrates a state in which a supporting operation is
performed as the front end portion 2a of the slab 2 passes the
first rolling stand 21, and (d) of FIG. 3 illustrates a reducing
operation in which the front end portion 2a of the slab 2 enters
the second rolling stand 22 to be reduced.
[0070] Referring to (a) through (d) of FIG. 3 and FIG. 6, the
rolling operation of a continuous casting and rolling method
according to an exemplary embodiment includes an inputting
operation of allowing the front end portion 2a of the slab 2 to
pass through the first rolling stand 21, which is open, a
supporting operation of allowing the pair of rolling rolls 21a
provided in the first rolling stand 21 after the front end portion
2a of the slab 2 passes the first rolling stand 21 to be in close
contact with the slab 2, and a reducing operation of reducing the
slab 2 by the second rolling stand 22, when the front end portion
2a of the slab 2 enters the second rolling stand 22 provided after
the first rolling stand 21.
[0071] In other words, as one example of a specific operation of
the rolling operation, an inputting operation, a supporting
operation, a reducing operation, and the like may be sequentially
provided.
[0072] The inputting operation is an operation of allowing the
front end portion 2a of the slab 2 to pass while the first rolling
stand 21 is open. In other words, when reducing with respect to the
front end portion 2a of the slab 2 is performed from the first
rolling stand 21, the slab 2 is not prevented from moving
backwards. Thus, the pair of rolling rolls are positioned while a
distance between the pair of rolling rolls 21a provided in the
first rolling stand is set to be greater than a thickness the slab
2.
[0073] The supporting operation is an operation of preventing
backward force from being generated by supporting the slab 2 when
the slab 2 is reduced in a subsequent reducing operation.
[0074] In other words, after the front end portion 2a of the slab 2
passes the first rolling stand 21, the pair of rolling rolls 21a,
provided in the first rolling stand 21, are provided to be in close
contact with the slab 2, so the slab 2 is held thereby and is not
pushed backwards.
[0075] In this case, a case in which the pair of rolling rolls 21a
are in close contact with the slab 2 refers to that the pair of
rolling rolls are provided to move in a direction of a position of
the slab 2 with applied force sufficient to hold the slab 2 rather
than applied force sufficient to reduce the slab 2.
[0076] In other words, a width of the pair of rolling rolls 21a
provided in the first rolling stand 21 may be provided to a degree
corresponding to a thickness of the slab 2.
[0077] The reducing operation is an operation of performing a
rolling operation by reducing the slab 2 using a pair of rolling
rolls provided in the second rolling stand 22, when the front end
portion 2a of the slab 2 enters the second rolling stand 22.
[0078] In this case, the applied force with which the pair of
rolling rolls of the second rolling stand 22 reduces the slab 2 may
not be greater than a force with which the first rolling stand 21
reduces the slab 2 as described previously, and a distance between
the pair of rolling rolls of the second rolling stand 22 may be
smaller than a distance between a pair of rolling rolls provided in
the first rolling stand 21.
[0079] As described above, a portion in which a length is increased
and which is generated by reducing the slab 2 in the reducing
operation moves not backward but forward due to supporting
operation.
[0080] FIG. 4 is a side view illustrating another example of a case
in which the front end portion 2a of the slab 2 is input into the
rolling mill 20 in the continuous casting and rolling apparatus 1
according to an exemplary embodiment, and FIG. 7 is a flow diagram
illustrating another example of a rolling operation in a continuous
casting and rolling method according to an exemplary
embodiment.
[0081] Referring to FIGS. 4 and 7, the rolling operation of a
continuous casting and rolling method according to an exemplary
embodiment includes an inputting operation of allowing the front
end portion 2a of the slab 2 to pass through the first rolling
stand 21, which is open, a reducing operation of reducing the slab
2 by the second rolling stand 22, when the front end portion 2a of
the slab 2 enters the second rolling stand 22 provided after the
first rolling stand 21, and a buffering operation of allowing a
pair of rolling rolls 21a provided in the first rolling stand 21 to
move upwardly or downwardly, or allowing a pair of pinch rolls
provided to an inlet of the first rolling stand to move upwardly or
downwardly, when a portion of the slab 2, having been reduced,
moves backwards to the first rolling stand 21.
[0082] In other words, as another example of a specific operation
of the rolling operation, an inputting operation, a reducing
operation, a buffering operation, and the like may be sequentially
provided.
[0083] The inputting operation is an operation of allowing the
front end portion 2a of the slab 2 to pass while the first rolling
stand 21 is open, and is the same as described above.
[0084] The reducing operation is an operation of operating a
rolling operation by reducing the slab 2 by a pair of rolling rolls
provided in the second rolling stand 22, when the front end portion
2a of the slab 2 enters the second rolling stand 22.
[0085] In this case, as the slab 2 is reduced, depending on a
thickness of the slab 2, having been reduced, the slab 2 is
increased. Thus, a portion in which a length is increased may be
generated. The portion in which a length is increased may include
not only a portion moving forward in a direction in which the slab
2 enters the rolling mill 20, but also a portion moving backwards
in a direction of the continuous caster 10.
[0086] The portion, moving backwards, is counterbalanced by a
buffering operation which will be described later, so it is
prevented from affecting the continuous caster 10, and the
like.
[0087] The buffering operation is an operation of absorbing
backward force generated in the reducing operation. In other words,
the slab 2 is moved by the pair of rolling rolls 21a, provided in a
rolling stand, in a direction perpendicular to a direction in which
the slab enters the rolling mill 20, so a portion in which a length
is increased and which is generated in the reducing operation may
be accommodated.
[0088] Here, the region in the direction perpendicular thereto
refers to a region in an upward direction or in a downward
direction of a direction in which the slab 2 enters the rolling
mill 20.
[0089] Similarly, in the buffering operation, pinch rolls are
provided separately from the pair of rolling rolls 20a. Thus, it is
not the rolling rolls 20a that are moved in the region in a
perpendicular direction, but the pinch rolls. Thus, a portion in
which a length is increased and which is generated in the reducing
operation may be accommodated.
* * * * *