【Invention Title】
CONTINUOUS CASTING-MILLING EQUIPMENT CAPABLE OF
SWITCHING BETWEEN CONTINUOUS AND BATCH MILLING, AND METHOD
5 THEREFOR
【Technical Field】
[0001] The present disclosure relates to continuous casting
and rolling equipment switching between continuous rolling and
10 batch rolling, capable of improving percentage yields by
reducing an amount of scrap discarded during switching casting
types or in an initial stage of casting, and to a method of the
same.
15 【Background Art】
[0002] Continuous casting and rolling equipment of the related
art has been known for having the same structure as the
embodiment of Patent Document 1, that is, a method of providing
a holding furnace between a caster and a rolling line and a method
20 of providing a coiler or a coiling box between a primary rolling
line and a secondary rolling line in the same manner as Patent
Document 2.
[0003] In detail, methods and equipment for performing
continuous rolling after continuous casting, according to steel
Page 3
grades or operation conditions, in the same manner as Patent
Document 1, or performing batch rolling by cutting slabs after
continuous casting in a case in which temperatures at which
rolling is possible are not secured, have been proposed.
5 [0004] In the case of continuous casting and continuous rolling
performed in such a manner that slabs are connected during
processes from casting to rolling, since the speed of continuous
casting is lower than that of rolling, rolling may be performed
more slowly than batch rolling in which rolling and continuous
10 casting are separately performed. In addition, in a case in
which predetermined temperature conditions are not satisfied,
rolling may be difficult. Thus, in the case of continuous
casting and continuous rolling, it is important to set
temperatures of slabs to be higher than a specific temperature
15 in a final rolling stand.
[0005] Thus, even in the case of equipment capable of
continuous and batch rolling, when temperatures of slabs are
relatively low in an initial stage of casting, it may be
difficult to perform continuous rolling. Thus, there is a
20 problem in which casting should be begun with batch rolling.
Patent Document 1: JP 2009-508691 A
Patent Document 2: EP 0841995 A
25 【Disclosure】
Page 4
【Technical Problem】
[0006] An aspect of the present disclosure may provide
continuous casting and rolling equipment switching between
continuous rolling and batch rolling for improving a percentage
5 yield of a process by reducing a portion thereof, which is
inevitably discarded as scrap, when casting is switched or in
an initial stage of casting.
【Technical Solution】
10 [0007] According to an aspect of the present disclosure, a
method of continuous casting and rolling, switching continuous
rolling and batch rolling, in equipment including a continuous
casting unit, at least two rolling portions, and a coiling box
disposed between the at least two rolling portions comprises
15 performing continuous casting to produce a slab; primary
rolling to reduce a thickness of the slab; cutting to cut a
specific length of the slab from a front end portion thereof
in an initial stage of casting; passing, in which the stab,
continuously provided, passes through the coiling box; and
20 secondary rolling to reduce a thickness of the slab having
passed through the coiling box.
[0008] In this case, in the primary rolling, the thickness of
the slab may be reduced using a rolling reduction rate lower
than a normal rolling reduction rate.
Page 5
[0009] In addition, heating to increase a temperature of the
slab passing between the cutting and the passing may be further
performed.
[0010] In an exemplary embodiment, in the heating, the
5 temperature of the slab may be increased to be higher than a
normal raised temperature.
[0011] In an exemplary embodiment, in the heating, the
temperature of the slab may be increased to be higher than the
normal raised temperature by 20°C to 50°C.
10 [0012] In addition, after the primary rolling, measuring a slab
temperature to measure the temperature of the slab is performed,
and in the cutting, the slab may be cut based on the temperature
of the slab.
[0013] In the measuring a slab temperature, the temperature
15 of the slab having passed through a first rolling portion may
be measured.
[0014] In an exemplary embodiment, in the cutting, a
temperature when the slab passes through a second rolling
portion may be predicted, and the slab may be cut until the
20 temperature when the slab passes through the second rolling
portion is higher than or equal to a temperature at which rolling
is possible.
[0015] In an exemplary embodiment, in the secondary rolling,
the slab may be rolled using a rolling reduction rate higher
25 than the normal rolling reduction rate.
Page 6
[0016] In an exemplary embodiment, in the primary rolling and
the secondary rolling, the rolling reduction rate may be
returned to the normal rolling reduction rate after a specific
period of time, while, in the primary rolling, the rolling
5 reduction rate may be gradually increased.
[0017] According to an aspect of the present disclosure,
equipment switching between continuous rolling and batch
rolling comprises a continuous casting unit; a first rolling
portion and a second rolling portion, disposed in a direction
10 of movement of a slab produced by the continuous casting unit
and rolling the slab; a coiling box disposed between the first
rolling portion and the second rolling portion and configured
to allow the slab having passed through the first rolling
portion to be coiled and uncoiled during batch rolling and to
15 merely pass through the coiling box during continuous rolling;
a cutter disposed between the first rolling portion and the
coiling box; a sensor for measuring a slab temperature disposed
on a rear portion of the first rolling portion; and a control
unit connected to the first rolling portion, the second rolling
20 portion, the coiling box, the cutter, and the sensor for
measuring a slab temperature. The control unit enables the
cutter to cut a portion of the slab cast in an initial stage
of casting based on a value measured by the sensor for measuring
a slab temperature during an initial stage of casting. In
25 addition, the control unit enables the coiling box to allow the
Page 7
slab connected to the continuous casting unit to pass through
the coiling box.
[0018] In this case, a heating portion disposed between the
cutter and the coiling box and increasing a temperature of the
5 slab passing therethrough may be further included. The control
unit may control the heating portion to increase the temperature
of the slab to be higher than a normal raised temperature.
[0019] In an exemplary embodiment, the control unit may
maintain a final thickness of the slab in such a manner that
10 a rolling reduction rate of the first rolling portion is reduced
to be lower than a normal rolling reduction rate, and a rolling
reduction rate of the second rolling portion is increased to
be higher than the normal rolling reduction rate.
[0020] In an exemplary embodiment, the coiling box is
15 configured to have a carousel type form. When the coiling box
allows the slab to pass therethrough, a mandrel of the coiling
box may be disposed above the slab passing therethrough.
[0021] In an exemplary embodiment, the heating portion may
include an inductive heater having an open side surface. The
20 inductive heater may be configured to enter and be removed in
a lateral direction of the slab.
[0022] In addition, in an exemplary embodiment, a pusher and
a piler, disposed between the heating portion and the cutter
and removing a slab having been cut from a path of the slab,
25 may be further included.
Page 8
【Advantageous Effects】
[0023] According to an aspect of the present disclosure,
continuous casting and rolling equipment switching between
5 continuous rolling and batch rolling for improving a percentage
yield of a process by reducing a portion thereof, which is
inevitably discarded as scrap, when casting is switched or in
an initial stage of casting, may be provided.
10 【Description of Drawings】
[0024] FIG. 1 is a view illustrating batch rolling in an
exemplary embodiment in the present disclosure.
[0025] FIG. 2 is a view illustrating continuous rolling in an
exemplary embodiment.
15
【Best Mode for Invention】
[0026] Hereinafter, exemplary embodiments in the present
disclosure will be described in detail with reference to the
attached drawings.
20 [0027] FIGS. 1 and 2 illustrate an exemplary embodiment in the
present disclosure. FIG. 1 illustrates continuous casting and
rolling equipment switching between continuous rolling and
batch rolling of an exemplary embodiment, performing batch
rolling. FIG. 2 illustrates continuous casting and rolling
Page 9
equipment switching between continuous rolling and batch
rolling, performing continuous rolling.
[0028] As illustrated in FIG. 1, the continuous casting and
rolling equipment switching between continuous rolling and
5 batch rolling of an exemplary embodiment includes a continuous
casting unit 10; a first rolling portion 20 disposed in a
direction of movement of a slab produced by the continuous
casting unit 10 and rolling the slab; temperature measuring
sensors 110, 111, 112, 113, and 114, measuring a temperature
10 of the slab having passed through the first rolling portion 20;
cutters 30 and 40 cutting the slab having passed through the
first rolling portion 20; a heating portion 50 heating a slab
not having been cut; a coiling box 60 configured in such a manner
that the slab having passed through the first rolling portion
15 20 and the heating portion 50 is coiled and uncoiled during batch
rolling and passes through the coiling box 60 during continuous
rolling; a second rolling portion 70 disposed to be contiguous
with the coiling box 60; a run out table 80 cooling a slab having
become a strip after rolling is finished; a cutter 90 cutting
20 the slab corresponding to an amount of a single coil; a coiler
100; and a control unit 120 connected to the first rolling
portion 20, the second rolling portion 70, the coiling box 60,
the cutters 30, 40, and 90, and the temperature measuring
sensors 110, 111, 112, 113, and 114.
25 [0029] In an exemplary embodiment, the continuous casting
Page 10
portion 10 may adopt any composition that may perform continuous
casting. In the exemplary embodiment, the continuous casting
portion 10 cools the slab in such a manner that a plurality of
segments, (not illustrated), are disposed below a mold.
5 [0030] The first rolling portion 20 is disposed to be
contiguous with the continuous casting portion 10 and applies
rolling force to the slab having passed through the continuous
casting portion 10, thereby rolling the slab to have a target
thickness. An exemplary embodiment of FIGS. 1 and 2 illustrates
10 a rolling portion including three stands, but the number of
stands may be increased or reduced according to need. The first
rolling portion 20 is connected to the control unit 120 and may
control a rolling reduction rate depending on a signal of the
control unit 120.
15 [0031] A temperature measuring sensor 110 is disposed on a rear
end portion of the first rolling portion 20 and measures a
temperature of a slab of which first rolling is finished. The
temperature measuring sensor 110 may be configured to be either
a contact type or a non-contact type. The temperature measuring
20 sensor 110 may be disposed in a plurality of positions, such
as on the rear end portion of the first rolling portion 20, as
well as on front and rear end portions of the heating portion
50 and the second rolling portion 70 and on a rear end portion
of the continuous casting portion 10, in order to detect a
25 temperature of the slab passing therethrough.
Page 11
[0032] The cutters 30, 40, and 90 are provided as three cutters
in an exemplary embodiment. Two cutters are disposed on the
rear end portion of the first rolling portion 20, while a cutter
is disposed on a front end portion of the coiler 100. In the
5 case of a cutter 30 disposed on the rear end portion of the first
rolling portion 20, a plurality of cutters are disposed
depending on a thickness of the slab. However, only a single
cutter may be used.
[0033] The heating portion 50 is configured using an inductive
10 heater having an open side surface in an exemplary embodiment.
In other words, the heating portion 50 is configured to have
a ‘⊏’ shape overall when taken from the front thereof, since
a side surface thereof is open. The inductive heater may be
connected to a means of movement to be able to enter and be
15 removed in a lateral direction of the slab. The inductive
heater may deviate from a path of the slab when heating is
unnecessary.
[0034] In addition, temperature measuring sensors 111 and 112
may be disposed on the front and rear end portion of the heating
20 portion 50. Thus, the control unit 120 may control the heating
portion 50 to increase a temperature of the slab to a desired
temperature.
[0035] In the meantime, although not illustrated in FIGS. 1
and 2, a pusher and piler (not illustrated) may be disposed in
25 a space between the cutters 30 and 40 and the heating portion
Page 12
50. The pusher and the piler push the slab cut by the cutters
30 and 40 out to remove the slab cut by the cutters from a path
of the slab. A cut slab removal device in addition to the pusher
and the piler may also be used.
5 [0036] In an exemplary embodiment, the coiling box 60 may
include two mandrels 61 and 62. The two mandrels 61 and 62 may
be configured to have a carousel type form having a structure
in which the two mandrels 61 and 62 rotate around a circular
track, and coiling and uncoiling are alternately performed. In
10 addition, in a case in which continuous rolling is performed
as illustrated in FIG. 2, in order not to block the path of the
slab, the coiling box 60 may be disposed in a higher position
so that a plurality of mandrels may be disposed above the slab
passing therethrough, but the present disclosure is not limited
15 thereto. In detail, the coiling box 60 may have a structure
in which the slab passes between the mandrels 61 and 62.
[0037] The second rolling portion 70 is disposed to be
contiguous with the coiling box 60. In the exemplary embodiment,
the second rolling portion 70 includes five rolling stands.
20 However, the second rolling portion 70 is not limited thereto,
but may include a plurality of rolling stands. In addition,
rolling stands may be disposed contiguously, and may be disposed
to be spaced apart from each other.
[0038] The second rolling portion 70 rolls the slab, a
25 thickness of which has been reduced by passing through the first
Page 13
rolling portion 20, using the plurality of rolling stands and
applies rolling force to the slab, so that a thickness thereof
may be reduced to a final target thickness. In this case, the
control unit 120 may manage a temperature of the second rolling
5 portion 70 to be a temperature at which rolling is possible,
using temperature measuring sensors 113 and 114 disposed on the
front and rear end portion of the second rolling portion 70.
[0039] The run out table 80 has a structure in which the slab,
having become a strip, is cooled using a cooling water supplying
10 device disposed thereabove by allowing the slab to pass through
a specific section above a roller. In the case of continuous
rolling, the cutter 90 cuts the slab having passed through the
run out table 80 to be an amount of a single coil before the
strip is wound around the coiler 100.
15 [0040] The control unit 120 is connected to each device and
may control a different device based on information of each
device. In detail, in an exemplary embodiment, the control unit
120 is connected to at least the first rolling portion 20, the
cutters 30 and 40, the heating portion 50, the coiling box 60,
20 the second rolling portion 70, and the temperature measuring
sensor 110 and controls the first rolling portion 20, the
cutters 30 and 40, the heating portion 50, the coiling box 60,
and the second rolling portion 70 based on a temperature value
of the temperature measuring sensor 110.
25 [0041] In the case of a structure described above, if casting
Page 14
is begun with continuous rolling in an initial stage of casting,
it is impossible to secure the temperature at which rolling is
possible before a portion of the slab, a temperature of which
is relatively low in the initial stage of casting, passes
5 through the last stand of the second rolling portion 70. In
addition, in the case of the structure of the exemplary
embodiment, when batch rolling is converted into continuous
rolling, mandrels 61 and 62 should be moved in the coiling box
60, so that the time to unwind a coil having been previously
10 wound may be required. Thus, a slab continuously cast while
the coil is being unwound should be cut using the cutters 30
and 40 to be discarded as scrap. In a case in which the slab
cast while the coil is being unwound is discarded as scrap, the
slab weighing 10 tons or more is discarded as scrap, thereby
15 significantly affecting a percentage yield.
[0042] Thus, the continuous casting and rolling equipment
switching between continuous rolling and batch rolling of an
exemplary embodiment begins casting with continuous rolling
allowing the slab to pass through a coiling box merely in the
20 initial stage of casting, using the control unit 120, while a
specific length of a front end portion of the slab is cut. In
this case, a cutting length may be controlled by the control
unit 120 so that a temperature of the slab before passing through
the last stand of the second rolling portion 70 may be a
25 temperature at which rolling is possible.
Page 15
[0043] In addition, in order to reduce the cutting length, in
an exemplary embodiment, when the heating portion 50 is in a
normal state, the slab is heated so that a temperature thereof
may be higher than a heating rate, thereby compensating for a
5 relatively low temperature in the initial stage. In this case,
the normal state refers to a time at which casting is stable.
[0044] In other words, when a temperature of the slab is
relatively low in the initial stage of casting, a quantity of
heat greater than a heating amount provided in the middle of
10 casting is provided. In this case, a temperature increasing
a temperature of the slab by the heating amount is increased
to a temperature higher than a normal state by 20°C to 50°C,
so that a temperature of the second rolling portion 70 may be
secured in the initial stage. In a case in which a difference
15 in raised temperatures is less than 20°C, an effect caused by
additional heating is insignificant. In a case in which a
difference in heat rates is greater than 50°C, a quality of the
slab may be affected. In addition, peripheral equipment of the
heating portion 50 may be degraded, and a reduction in lifespan
20 thereof may be affected.
[0045] In addition, the control unit 120 may improve plastic
energy dissipation of the slab in the second rolling portion
70 to secure the temperature of the second rolling portion 70
in such a manner that a rolling reduction rate of the first
25 rolling portion 20 is reduced to be lower than that in a normal
Page 16
state in the initial stage of casting, and a rolling reduction
rate of the second rolling portion 70 is increased to be higher
than that in the normal state.
[0046] In detail, in the case of the heating portion 50, when
5 a thickness of the slab is relatively thick, heating efficiency
may be improved. Thus, the rolling reduction rate of the first
rolling portion 20 may be reduced to be lower than that in the
normal state, thereby improving efficiency of the heating
portion 50 to increase a heating amount provided to the slab.
10 [0047] In case of the first rolling portion 20 and the second
rolling portion 70, in the normal state, maximum rolling force
is not used, but a certain margin is retained in case that there
is a problem, such as equipment trouble, during a process.
However, in the initial stage of casting, the control unit 120
15 reduces the rolling reduction rate of the first rolling portion
20 using a marginal rolling reduction rate of the second rolling
portion 70 and increases the rolling reduction rate of the
second rolling portion 70 to cover a relatively low temperature
of the slab in the initial stage using plastic energy
20 dissipation of the second rolling portion 70.
[0048] In the meantime, in a case in which a temperature of
the slab is secured after the slab has passed through the coiler
100 in the initial stage, the control unit 120 controls an
entirety of the first rolling portion 20 and the second rolling
25 portion 70 to have a marginal rolling reduction rate in such
Page 17
a manner that the rolling reduction rate of the first rolling
portion 20 is increased to be that in the normal state and the
rolling reduction rate of the second rolling portion 70 is
reduced to be that in the normal state. In this case, rolling
5 reduction rates of the first rolling portion 20 and the second
rolling portion 70 may gradually be changed.
[0049] However, even though a rolling reduction rate and the
heating portion 50 are controlled as described above, in a
certain section in the initial stage of casting, a temperature
10 at which rolling is possible may not be secured in the second
rolling portion 70. Thus, the control unit 120 measures a
temperature of the slab having passed through the first rolling
portion 20 using the temperature measuring sensor 110 disposed
on an exit side of the first rolling portion 20. The control
15 unit 120 predicts a temperature of the slab when the slab passes
through the second rolling portion 70 in consideration of a
measured temperature, a heating amount that the heating portion
50 may provide, and a heating amount lost from the slab while
the slab is passing through the heating portion 50, the coiling
20 box 60, and the second rolling portion 70. In a case in which
the temperature of the slab is lower than the temperature at
which rolling is possible, the section of the slab, the
temperature of which is relatively low, is cut by the cutters
30 and 40.
25 [0050] In the meantime, the control unit 120 may control to
Page 18
prevent a collision occurring when the slab enters the first
rolling portion 20 in such a manner that the first rolling
portion 20 applies rolling force thereto after a front end
portion of the slab passes through the first rolling portion
5 20 in the initial stage.
[0051] A method of operating the continuous casting and rolling
equipment switching between continuous rolling and batch
rolling described above will be described.
[0052] In order to begin casting with continuous rolling in
10 the initial stage of casting, as illustrated in FIG. 2, the
coiling box 60 begins casting with the mandrels 61 and 62 moved
above the path of the slab.
[0053] After a continuous casting operation to continuously
cast the slab in a continuous casting portion, in order to
15 prevent a problem related to the slab entering the first rolling
portion 20 in the initial stage of casting, a primary rolling
operation in which the first rolling portion 20 begins to apply
roll force thereto after the front end portion of the slab passes
therethrough is performed. In this case, a temperature
20 measuring operation to measure a temperature of the slab having
passed through the first rolling portion 20 using the
temperature measuring sensor 110 is performed. Based on a
measured temperature, a temperature when the slab passes
through the second rolling portion 70 is predicted. In a case
25 in which the temperature is lower than the temperature at which
Page 19
rolling is possible, a cutting operation to cut the slab using
the cutters 30 and 40 is performed. In the cutting operation,
it is possible to cut the slab uniformly at a length obtained
based on experience without the temperature measuring operation.
5 However, based on a temperature value in the temperature
measuring operation, the cutting length may be reduced, thereby
improving a percentage yield.
[0054] A slab having been cut is removed from the path of the
slab. In the case of a slab not having been cut and connected
10 to the continuous casting portion 10, a heating operation to
raise a temperature of the slab using the heating portion 50
is performed. In order to provide a larger quantity of heat
by improving efficiency of a temperature rise and to raise a
temperature on a rear end portion of the slab by plastic energy
15 dissipation, in the first rolling portion 20, rolling reduction
is performed using a rolling reduction rate lower than that in
the normal state in the primary rolling operation.
Insufficient rolling reduction in the first rolling portion 20
is compensated for in such a manner that rolling reduction
20 greater than that in the normal state in the second rolling
portion 70 is performed in a secondary rolling operation to be
subsequently described.
[0055] After the heating operation, a passing operation in
which the slab merely passes through the coiling box 60.
25 Subsequently, the secondary rolling operation is performed by
Page 20
the second rolling portion 70. In the secondary rolling
operation as described above, rolling reduction is performed
to the slab using a rolling reduction rate higher than that in
the normal state, while a portion thereof in which rolling
5 reduction is not performed in the primary rolling operation is
compensated for.
[0056] According to a method of an exemplary embodiment, a
coiling box is controlled so that continuous rolling may be
performed in the initial stage of casting, and a portion of the
10 slab in which continuous rolling may not be performed is cut,
thereby reducing an amount of scrap generated during a switch
between continuous rolling and batch rolling or in the initial
stage of casting. Thus, a percentage yield may be improved.
[0057] In addition, the heating amount is increased and plastic
15 energy dissipation is used to reduce a portion of the slab in
which continuous rolling may not be performed, thereby
generating scrap only about 20% to 30% of scrap generated when
batch rolling is switched to continuous rolling. Thus, the
switch between batch rolling and continuous rolling is possible,
20 thereby greatly contributing to improving a percentage yield.
Exemplary Example
[0058] Table 1 below is a contrast table contrasting a case
in which rolling in the initial stage is performed on condition
25 of continuous casting and rolling equipment switching between
Page 21
continuous rolling and batch rolling in a normal state and a
case in which rolling is performed using a method of the present
disclosure.
[0059] A rolling reduction rate of a first rolling portion was
5 reduced to be lower than that in the normal state, and a rolling
reduction rate of a second rolling portion was increased, so
that an entirety of rolling reduction rates were equal, and a
degree of temperature rise of a heating portion was increased
to be higher than that in the normal state by 45°C. As a result,
10 there was a temperature difference of about 20°C between a
temperature on an exit side of the second rolling portion 70
in the initial stage and a temperature in the normal state. Thus,
an amount of discarded scrap was significantly reduced, thereby
improving a percentage yield.
15
【Table 1】
Item Comparative Example
(Normal State)
Exemplary Example
Rolling Reduction
Rate of First
Rolling Portion
60% 55%
Degree of
Temperature Rise
of Heating Portion
100℃ 145℃
Page 22
Rolling Reduction
Rate of Second
Rolling Portion
80% 82%
Temperature on Exit
Side of Second
Rolling Portion in
Initial Stage
About 780℃ About 800℃
Amount of Scrap 15 tons 5 tons
[0060] In a case in which a certain degree of casting in the
initial stage and rolling is performed, for example, about four
coils are produced, and a stable temperature on the exit side
5 thereof is secured, a slab is returned to the normal state so
that each component of the continuous casting and rolling
equipment switching between continuous rolling and batch
rolling may have a marginal operation range.
[0061] While exemplary embodiments have been shown and
10 described above, it will be apparent to those skilled in the
art that modifications and variations could be made without
departing from the scope of the present invention as defined
by the appended claims.

【WE CLAIM:】
【Claim 1】
A method of continuous casting and rolling, switching
5 continuous rolling and batch rolling, in equipment including
a continuous casting unit, at least two rolling portions, and
a coiling box disposed between the at least two rolling portions,
the method comprising:
performing continuous casting to produce a slab;
10 primary rolling to reduce a thickness of the slab;
cutting to cut a specific length of the slab from a front
end portion of the slab in an initial stage of casting;
passing, in which the slab, continuously provided, passes
through the coiling box; and
15 secondary rolling to reduce a thickness of the slab having
passed through the coiling box.
【Claim 2】
The method of claim 1, wherein in the primary rolling,
20 the thickness of the slab is reduced using a rolling reduction
rate lower than a rolling reduction rate in normal condition.
【Claim 3】
The method of claim 2, further comprising heating, to
Page 24
increase a temperature of the slab, between the cutting and the
passing.
【Claim 4】
5 The method of claim 3, wherein in the heating, the
temperature of the slab is increased to be higher than a raised
temperature in normal condition.
【Claim 5】
10 The method of claim 4, wherein in the heating, the
temperature of the slab is increased to be higher than the raised
temperature in normal condition by 20°C to 50°C.
【Claim 6】
15 The method of claim 2, wherein after the primary rolling,
measuring a slab temperature to measure the temperature of the
slab is performed, and in the cutting, the slab is cut based
on the temperature of the slab.
20 【Claim 7】
The method of claim 6, wherein in the measuring a slab
temperature, the temperature of the slab having passed through
a first rolling portion is measured.
Page 25
【Claim 8】
The method of claim 7, wherein in the cutting, a
temperature when the slab passes through a second rolling
portion is predicted, and the slab is cut until the temperature
5 when the slab passes through the second rolling portion is
higher than or equal to a temperature at which rolling is
possible.
【Claim 9】
10 The method of claim 6, wherein in the secondary rolling,
the slab is rolled using a rolling reduction rate higher than
the rolling reduction rate in normal condition.
【Claim 10】
15 The method of claim 9, wherein in the primary rolling and
the secondary rolling, the rolling reduction rate is returned
to the rolling reduction rate in normal condition after a
specific period of time.
20 【Claim 11】
The method of claim 2, wherein in the primary rolling,
the rolling reduction rate is gradually increased.
【Claim 12】
Page 26
Continuous casting and rolling equipment switching
between continuous rolling and batch rolling, comprising:
a continuous casting unit;
a first rolling portion and a second rolling portion,
5 disposed in a direction of movement of a slab produced by the
continuous casting unit and rolling the slab;
a coiling box disposed between the first rolling portion
and the second rolling portion and configured to allow the slab
having passed through the first rolling portion to be coiled
10 and uncoiled during batch rolling and to merely pass through
the coiling box during continuous rolling;
a cutter disposed between the first rolling portion and
the coiling box;
a sensor for measuring a slab temperature disposed on a
15 rear portion of the first rolling portion; and
a control unit connected to the first rolling portion,
the second rolling portion, the coiling box, the cutter, and
the sensor for measuring a slab temperature,
wherein the control unit enables the cutter to cut a
20 portion of the slab cast in an initial stage of casting based
on a value measured by the sensor for measuring a slab
temperature during an initial stage of casting and enables the
coiling box to allow the slab connected to the continuous
casting unit to pass through the coiling box.
25
Page 27
【Claim 13】
The continuous casting and rolling equipment switching
between continuous rolling and batch rolling of claim 12,
further comprising a heating portion disposed between the
5 cutter and the coiling box and increasing a temperature of the
slab passing through the heating portion,
wherein the control unit controls the heating portion to
increase the temperature of the slab to be higher than a raised
temperature in normal condition.
10
【Claim 14】
The continuous casting and rolling equipment switching
between continuous rolling and batch rolling of claim 13,
wherein the control unit maintains a final thickness of the slab
15 in such a manner that a rolling reduction rate of the first
rolling portion is reduced to be lower than a rolling reduction
rate in normal condition, and a rolling reduction rate of the
second rolling portion is increased to be higher than the
rolling reduction rate in normal condition.
20
【Claim 15】
The continuous casting and rolling equipment switching
between continuous rolling and batch rolling of claim 12,
wherein the coiling box is configured to have a carousel type
Page 28
form including a plurality of mandrels, and when the coiling
box allows the slab to pass through the coiling box, a mandrel
of the coiling box is disposed above the slab passing through
the coiling box.
5
【Claim 16】
The continuous casting and rolling equipment switching
between continuous rolling and batch rolling of claim 13,
wherein the heating portion includes an inductive heater having
10 an open side surface, and the inductive heater is configured
to enter and be removed in a lateral direction of the slab.
【Claim 17】
The continuous casting and rolling equipment switching
15 between continuous rolling and batch rolling of claim 13,
further comprising a pusher and a piler, disposed between the
heating portion and the cutter and removing a slab having been
cut from a path of the slab.