【Technical Field】
[0001] The present disclosure relates to an endless rolling
apparatus and a method of controlling the same, and more
particularly, to an endless rolling apparatus with which the
occurrence of loops in a steel plate may be prevented, and a
10 method of controlling the same.
【Background Art】
[0002] In general, endless rolling refers to processes in which
steel plates are continuously produced using equipment in which
continuous casting apparatuses and rolling mills are connected
15 to each other such that steel plates are produced in continuous
casting apparatuses, casting equipment, and the steel plates
produced in the continuous casting apparatuses may be rolled
to ultimate thicknesses while being passed through rolling
mills.
20 [0003] FIGS. 1A and 1B are schematic views illustrating an
endless rolling apparatus according to the related art.
[0004] With reference to FIG. 1A, an endless rolling apparatus
according to the related art includes a continuous casting
apparatus 1 producing a steel plate S, a roughing rolling mill
25 2 connected to the continuous casting apparatus 1, a finishing
Page 3
rolling mill 3 connected to the roughing rolling mill 2 to roll
the steel plate S to have an ultimate thickness, a cutter 4
cutting the steel plate S having passed through the finishing
rolling mill 3, and a winding apparatus 5, winding the steel
5 plate S.
[0005] In this case, the finishing rolling mill 3 is provided
with a plurality of rolling stands including an upper rolling
roll and a lower rolling roll. A rolling roll of at least one
of the rolling stands may be spaced apart from the steel plate
10 S, such that rolling may be performed in a dummy rolling process
applied thereto, as required.
[0006] The case as described above is provided to prevent a
problem in which a large amount of heat loss occurs due to contact
of the steel plate S with a rolling roll in the case of the steel
15 plate S rolled through the finishing rolling mill 3 to thus
affect the quality of the steel plate S. For example, the number
of rolling rolls in contact with the steel plate S may be reduced
to prevent heat loss.
[0007] However, in such a dummy rolling process, when the steel
20 plate S is cut by the cutter 4 as illustrated in FIG. 1B, as
tension is removed from a cut region of the steel plate S, loops
may occur in the steel plate S. As a result, a problem, in which
a surface of the steel plate S is damaged due to contact or
friction with a rolling roll spaced apart therefrom or a
25 peripheral device, and the quality of an ultimately obtained
Page 4
product is deteriorated, may be present.
【Technical Problem】
[0008] In order to solve the problems as described above, an
5 aspect of the present disclosure is to provide an endless
rolling apparatus, with which the occurrence of a loop in a steel
plate may be prevented by applying a predetermined level of
tension to a steel plate, and a method of controlling the same.
[0009] Further, in order to solve the above-mentioned problems,
10 an aspect of the present disclosure is to provide an endless
rolling apparatus, with which a steel plate may be prevented
from sagging in a finishing rolling mill by providing a steel
plate support unit between finishing rolling mills, and a method
of controlling the same.
15 【Technical Solution】
[0010] According to an aspect of the present disclosure, an
endless rolling apparatus includes a continuous casting
apparatus producing a steel plate; a rolling mill disposed
behind the continuous casting apparatus and rolling the steel
20 plate; a cutter disposed behind the rolling mill and cutting
the steel plate; and a tension applying unit disposed between
the rolling mill and the cutter, and applying tension to a steel
plate present in the rolling mill, having been cut by the cutter.
[0011] The tension applying unit may include a base frame; a
25 pressing roll rotatably disposed on the base frame, and
Page 5
including an upper roll pressing an upper surface of the steel
plate and a lower roll pressing a lower surface of the steel
plate; a driving motor disposed on the base frame and rotating
the pressing roll; and a lift unit disposed on the base frame
5 and moving the upper roll up, and down toward the lower roll.
[0012] The lift unit may include an upper roll support block
installed to be slidably moved on the base frame, and supporting
the upper roll to be rotated; and an upper roll actuator
installed on the base frame, and moving the upper roll via a
10 load connected to the upper roll support block.
[0013] The lift unit may include a pressure measuring unit
measuring a pressure at which the upper roll presses the steel
plate; and a tension controller receiving data from the pressure
measuring unit, and controlling operations of the upper roll
15 actuator, in such a manner that the upper roll presses the steel
plate to obtain a target pressure.
[0014] The tension applying unit further may include a torque
measuring unit measuring a torque value applied to the pressing
roll, and the tension controller may receive a torque value
20 applied to the pressing roll via the torque measuring unit, and
may control a rotation speed of the driving motor, such that
the torque value of the pressing roll converges with a target
torque value derived by the following equation: T = UT × w ×
t × r, where T is a target torque value, UT is a level of tensile
25 stress required to prevent slippage between the steel plate and
Page 6
the upper roll, w is a width of the steel plate, t is a thickness
of the steel plate, and r is a radius of the pressing roll.
[0015] When the torque value of the pressing roll is lower than
a threshold torque value at which the slippage between the
5 pressing roll and the steel plate occurs, the tension controller
may control a target pressure value to be increased, such that
the torque value of the pressing roll converges with the target
torque value.
[0016] The rolling mill may include a plurality of rolling
10 stands including an upper rolling roll and a lower rolling roll,
and in this case, the endless rolling apparatus may further
include a steel plate support unit disposed between the
plurality of rolling stands to support the steel plate.
[0017] The steel plate support unit may include a frame; a
15 support roll pressing and supporting one side of the steel plate;
and a support roll actuator having one side fixed to the frame
and the other side supporting the support roll to be rotated,
and moving the support roll to one side of the steel plate.
[0018] The steel plate support unit may further include a steel
20 plate detection sensor sensing entry of the steel plate into
the rolling mill; and a support controller controlling
operations of the support roll actuator, to move the support
roll to a position at the same height as a height of the lower
rolling roll of the rolling mill when movement of the steel plate
25 is sensed by the steel plate detection sensor, and to move the
Page 7
support roll to a position at a height lower than the height
of the lower rolling roll of the rolling mill when there is no
movement of the steel plate.
[0019] In the rolling mill, an upper rolling roll of any one
5 of the plurality of the rolling stands may be disposed to be
spaced apart from the steel plate, such that the upper rolling
roll is not in contact with the steel plate, and the steel plate
support unit may be disposed behind the rolling stand having
the upper rolling roll spaced apart from the steel plate.
10 [0020] According to an aspect of the present disclosure, a
method of controlling an endless rolling apparatus includes
performing a continuous casting operation of producing a steel
plate; rolling the steel plate produced in the continuous
casting operation using a rolling mill; cutting the steel plate
15 rolled in the rolling, using a cutter; and applying tension to
a steel plate present in the rolling mill, having been cut in
the cutting, using a tension applying unit.
[0021] The applying of tension may include pressing the steel
plate with an upper roll of the tension applying unit; measuring
20 a pressure at which the upper roll presses the steel plate; and
controlling movement of the upper roll, such that a pressure
value measured in the measuring of pressure converges with a
target pressure value.
[0022] The applying of tension may include: measuring a torque
25 value applied to a pressing roll in the tension applying unit;
Page 8
setting a target torque value of the pressing roll using the
following equation: T = UT × w × t × r, where T is a target torque
value, UT is a level of tensile stress required to prevent
slippage between the steel plate and the upper roll, w is a width
5 of the steel plate, t is a thickness of the steel plate, and
r is a radius of the pressing roll; and controlling a rotation
speed of the pressing roll, such that the torque value measured
in the measuring of a torque value converges with the target
torque value.
10 [0023] The applying of tension further may include changing
a target pressure to increase the target pressure value, such
that the torque value of the pressing roll converges with the
target torque value, when the torque value of the pressing roll
is lower than a threshold torque value at which slippage between
15 the pressing roll and the steel plate occurs.
[0024] The rolling mill may include a plurality of rolling
stands including an upper rolling roll and a lower rolling roll,
and in this case, the method of controlling an endless rolling
apparatus may further include supporting the steel plate with
20 a steel plate support unit disposed between the plurality of
rolling stands.
[0025] The supporting of the steel plate may include a steel
plate entry sensing operation of sensing entry of the steel
plate into the rolling mill; a support location movement
25 operation of moving a support roll of the steel plate support
Page 9
unit to a position at the same height as a height of the lower
rolling roll of the rolling mill when movement of the steel plate
is sensed in the steel plate entry sensing operation; and a
standby location movement operation of moving the support roll
5 to a position at a height lower than a height of the lower rolling
roll when there is no movement of the steel plate.
【Advantageous Effects】
[0026] In the case of an endless rolling apparatus and a method
of controlling the same according to an exemplary embodiment
10 in the present disclosure, the occurrence of a loop in a steel
plate may be prevented by adding tension to the steel plate,
thereby preventing a surface of the steel plate from being
damaged.
[0027] In addition, according to an exemplary embodiment, for
15 example, in the case in which a change in a level of tension
applied to a steel plate occurs due to the use of equipment for
a long period of time, the change may be sensed and controlled
such that tension may be continually applied to a steel plate
as required, thereby improving a product quality.
20 [0028] In addition, according to an exemplary embodiment, a
steel plate support unit may be provided between finishing
rolling mills to prevent a steel plate from sagging in finishing
rolling mills, thereby improving the quality of a product.
25 【Description of Drawings】
Page 10
[0029] FIG. 1A is a schematic view illustrating an endless
rolling apparatus according to the related art.
[0030] FIG. 1B is a schematic view illustrating a state in which
a loop phenomenon occurs in an endless rolling apparatus
5 according to the related art.
[0031] FIG. 2 is a schematic view of an endless rolling
apparatus according to an exemplary embodiment in the present
disclosure.
[0032] FIG. 3 is a front view schematically illustrating a
10 tension applying unit in an endless rolling apparatus according
to an exemplary embodiment in the present disclosure.
[0033] FIG. 4 is a block diagram schematically illustrating
portions of the configuration of a tension applying unit in an
endless rolling apparatus according to an exemplary embodiment
15 in the present disclosure.
[0034] FIG. 5 provides front views schematically illustrating
a steel plate support unit in an endless rolling apparatus
according to an exemplary embodiment in the present disclosure.
[0035] FIG. 6 is a control flowchart schematically
20 illustrating a method of controlling an endless rolling
apparatus according to an exemplary embodiment in the present
disclosure.
[0036] FIG. 7 is a control flowchart schematically
illustrating a method of controlling a tension applying unit
25 in an endless rolling apparatus controlling method according
Page 11
to an exemplary embodiment in the present disclosure.
[0037] FIG. 8 is a control flowchart schematically
illustrating a method of controlling a tension applying unit
in a specific situation in a method of controlling an endless
5 rolling apparatus according to an exemplary embodiment in the
present disclosure.
[0038] FIG. 9 is a control flowchart schematically
illustrating a method of controlling a steel plate support unit
in a method of controlling an endless rolling apparatus
10 according to an exemplary embodiment in the present disclosure.
【Mode for Invention】
[0039] In order to facilitate understanding of the features
according to an exemplary embodiment in the present disclosure,
15 hereinafter, an endless rolling apparatus according to an
exemplary embodiment and a method of controlling the same will
be described in detail.
[0040] Further, in order to facilitate understanding of
exemplary embodiments described below, with reference to
20 reference numerals of the same components in the accompanying
drawings, like numerals refer to like components, even in
different drawings. In the following description of the
present disclosure, a detailed description of functions and
configurations below, known in the art, will be omitted in a
25 case in which subject matter of the invention is rather unclear.
Page 12
[0041] Hereinafter, detailed embodiments in the present
disclosure will be described with reference to the accompanying
drawings.
[0042] FIG. 2 is a schematic view of an endless rolling
5 apparatus according to an exemplary embodiment.
[0043] With reference to FIG. 2, an endless rolling apparatus
according to an exemplary embodiment in the present disclosure
may include a continuous casting apparatus 10 producing a steel
plate S, a rolling mill 30 disposed in a direction in which the
10 steel plate S is moved forward, to roll the steel plate S, a
cutter 40 disposed in front of the rolling mill 30 to cut the
steel plate S, and a tension applying unit 100 disposed between
the rolling mill 30 and the cutter 40 and applying tension to
a steel plate S present in the rolling mill 30, having been cut
15 by the cutter 40.
[0044] In this case, the rolling mill 30 refers to a finishing
rolling mill, and the rolling mill 30 may be provided with a
plurality of rolling stands including an upper rolling roll and
a lower rolling roll. Reference numeral 20 denotes a roughing
20 rolling mill primarily pressing the steel plate S to obtain a
reduction thereof, and reference numeral 50 denotes a winder
winding the rolled steel plate S. The continuous casting
apparatus 10, the roughing rolling mill 20, the finishing
rolling mill 30, the cutter 40, and the winder 50 may be the
25 configurations generally used in an endless rolling mill, and
Page 13
thus, a detailed description thereof will be omitted.
[0045] FIG. 3 is a front view schematically illustrating a
tension applying unit in an endless rolling apparatus according
to an exemplary embodiment. FIG. 4 is a block diagram
5 schematically illustrating portions of the tension applying
unit in the endless rolling apparatus.
[0046] With reference to FIGS. 3 and 4, the tension applying
unit 100 may be disposed between the rolling mill 30 and the
cutter 40, and may apply tension to a steel plate present in
10 the rolling mill 30, having been cut by the cutter 40, thereby
preventing occurrence of a loop in cutting the steel plate S.
[0047] In further detail with reference to FIG. 3, the tension
applying unit 100 may include a base frame 110, a pressing roll
rotatably disposed on the frame 110 and including an upper roll
15 140 pressing an upper surface of the steel plate S and a lower
roll 120 pressing a lower surface of the steel plate S, a driving
motor 130 disposed on the base frame 110 and rotating the upper
roll 140 and the lower roll 120, the pressing rolls, and a lift
unit 150 disposed on the base frame 110 and moving the upper
20 roll 140 up, and down toward the lower roll 120.
[0048] The lift unit 150 may include an upper roll support block
151 slidably mounted on the base frame 110 and supporting the
upper roll 140 to be rotated, and an upper roll actuator 152
disposed on the base frame 110 and moving the upper roll 140
25 by a load connected to the upper roll support block 151. In
Page 14
this case, a driving motor 130 rotating the upper roll 140 may
be installed on the upper roll support block 151.
[0049] In the configuration as described above, the upper roll
actuator 152 may press the upper roll 140 toward an upper surface
5 of the steel plate S, in such a manner that the steel plate S
may be in close contact with the lower roll 120, and the upper
roll 140 and the lower roll 120 may be rotated by the driving
motor 130, thereby applying tension to the steel plate S. At
this time, the upper roll 140 and the lower roll 120 may be
10 rotated at a speed higher than a speed at which the steel plate
S enters, thereby applying tension to the steel plate. For
example, a level of the tension applied to the steel plate S
may be adjusted by controlling a rotation speed of the upper
roll 140 and the lower roll 120.
15 [0050] In addition, the upper roll 140 should press the steel
plate S at a predetermined pressure or higher, to prevent
occurrence of slippage of the steel plate S between the upper
roll 140 and the lower roll 120.
[0051] In order to perform the operations as described above,
20 with reference to FIG. 4, the tension applying unit 100 may
include a pressure measuring unit 170 measuring a pressure at
which the upper roll 140 presses the steel plate S, a tension
controller 180 receiving data of the pressure measuring unit
170, and controlling operations of the upper roll actuator 152
25 such that the upper roll 140 presses the steel plate S to obtain
Page 15
a target pressure, and a torque measuring unit 160 measuring
a torque value applied to the upper roll 140 and the lower roll
120.
[0052] The tension controller 180 may receive the torque value
5 applied to the upper roll 140 and the lower roll 120, via the
torque measuring unit 160, and may control a rotation speed of
the driving motor 130, such that the torque values of the upper
roll 140 and the lower roll 120 of the driving motor 130 may
converge with a target torque value T derived by the following
10 equation: T = UT × w × t × r, where t is a target torque value,
UT is a level of tensile stress required to prevent the
occurrence of slippage between the steel plate S and the upper
roll, w is a width of the steel plate, t is a thickness of the
steel plate S, and r is a radius of each of the lower roll 140
15 and the lower roll 120.
[0053] The level of tensile stress UT required to prevent
slippage between the steel plate S and the upper roll may be
changed depending on a material of the steel plate S, and the
level of tensile stress UT may be derived through
20 experimentation. For example, when the steel plate S is
manufactured using general steel, the level of tensile stress
UT may correspond to 1.5kgf/mm2.
[0054] Thus, the target torque values of the upper roll 140
and the lower roll 120, required to apply required tension to
25 the steel plate S, may be set via the level of tensile stress
Page 16
UT based on a material of the steel plate S, the width w and
the thickness t of the steel plate S, radius (r) values of the
upper roll 140 and the lower roll 120.
[0055] For example, in the case in which the torque value of
5 the upper roll 140 and the lower roll 120 is lower than a
threshold torque value at which slippage between the upper and
lower rolls 140 and 120 and the steel plate S pressed thereby
occurs, the tension controller 180 may perform controlling to
increase a target pressure value such that the torque value of
10 the upper roll 140 and the lower roll 120 may converge with the
target torque value. In this case, the threshold torque value
may be set by a user, and may also be set to correspond to least
tension to be applied to the steel plate, even in the case which
no slippage occurs.
15 [0056] In detail, a target pressure value, at which tension
may be applied to the steel plate S disposed between the upper
roll 140 and the lower roll 120 without the occurrence of
slippage of the steel plate S therebetween, may be set, and the
upper roll 140 may press the steel plate S to obtain the target
20 pressure value, thereby applying tension to the steel plate S.
In this case, for example, when slippage occurs, frictional
force among the upper roll 140, the lower roll 120, and the steel
plate S may decrease, and thus, the torque value measured by
the torque measuring unit 160 may be decreased or be zero. Thus,
25 the tension controller 180 may perform controlling, such that
Page 17
the upper roll 140 operates to press the steel plate S by changing
the target pressure value to a value greater than a
predetermined value, and thus, the torque value of the upper
roll 140 and the lower roll 120 may be obtained by a target torque
5 value.
[0057] FIG. 5 provides front views schematically illustrating
a steel plate support unit in an endless rolling apparatus
according to an exemplary embodiment.
[0058] Referring to FIG. 5, a steel plate support unit 200 of
10 the endless rolling apparatus may be disposed between the
plurality of rolling stands in the rolling mill 30 to support
the steel plate S. For example, in the rolling mill 30, the
steel plate S may be rolled to obtain an ultimate thickness,
and in this case, the ultimate thickness thereof may also be
15 changed to be subjected to continuous rolling. In this case,
changing the thickness of the steel plate S refers to a change
in a rolling speed of roll in the rolling mill 30, and thus,
a loop phenomenon may instantaneously occur in the steel plate
S according to the change in the rolling speed of the rolling
20 roll in the continuous process.
[0059] Thus, the steel plate support unit 200 may be disposed
in the rolling mill 30 to support the steel plate S and thus
prevent the steel plate S from sagging.
[0060] The steel plate support unit 200 may include a frame
25 210, a support roll 220 pressing and supporting one side of the
Page 18
steel plate S, and a support roll actuator 230 having one side
fixed to the frame 210 and the other side supporting the support
roll 220 to be rotated to move the support roll 220 to one side
of the steel plate S.
5 [0061] In the configuration as described above, the steel plate
support unit 200 may be disposed, in such a manner that the
support roll 220 may be in contact with a lower surface of the
steel plate S to support the steel plate S, by an operation of
the support roll actuator 230, as illustrated in FIG. 5A, and
10 may also be disposed in such a manner that the support roll 220
is spaced apart from the steel plate S as required, as
illustrated in FIG. 5B.
[0062] The support roll 220 is not limited to a structure in
which the support roll 220 is moved up or down to be in close
15 contact with or separated from the steel plate S, and various
mechanical operating methods may be used. For example, the
support roll 220 may be rotated toward the steel plate S to be
in close contact with or to be separated from the steel plate
S.
20 [0063] In addition, the steel plate support unit 200 may
further include a steel plate detection sensor (not shown)
detecting entry of the steel plate S into the rolling mill 30,
and a support controller (not shown) controlling operations of
the support roll actuator 230, to move the support roll 220 to
25 a position at the same height as a height of the lower rolling
Page 19
roll of the rolling mill 30 when movement of the steel plate
S is sensed by the steel plate detection sensor, and to move
the support roll 220 to a position at a height lower than that
of the lower rolling roll when there is no movement of the steel
5 plate S.
[0064] Further, the support roll 220 may also be positioned
to be higher than the lower roll of the rolling mill 30 to apply
tension to the steel plate S, as required. The position control
of the support roll 220 as described above may be performed
10 during a process, as required.
[0065] In addition, for example, when an upper rolling roll
of one of the rolling stands in the rolling mill 20 is spaced
apart from the steel plate S, so as not to be in contact therewith,
the steel plate support unit 200 may be disposed behind the
15 rolling stand in which the upper rolling roll is spaced apart
from the steel plate. Thus, for example, when the upper rolling
rolls of the plurality of rolling stands in the rolling mill
30 are spaced apart from the steel plate, the steel plate support
unit 200 may be disposed behind each of the rolling stands in
20 which the upper rolling rolls are spaced apart from the steel
plate.
[0066] Hereinafter, a method of controlling the endless
rolling apparatus will be described. In the case of an
apparatus described below, the same configurations thereof as
25 the configurations described above are the same as those of the
Page 20
endless rolling apparatus, and thus, descriptions thereof and
reference numerals are omitted.
[0067] FIG. 6 is a control flowchart schematically
illustrating a method of controlling an endless rolling
5 apparatus according to an exemplary embodiment. FIG. 7 is a
control flowchart schematically illustrating a method of
controlling a tension applying unit in a method of controlling
an endless rolling apparatus according to an exemplary
embodiment. FIG. 8 is a control flowchart schematically
10 illustrating a control method in the case of the occurrence of
slippage in the tension applying unit.
[0068] Referring to FIG. 6, the method of controlling an
endless rolling apparatus according to an exemplary embodiment
may include a continuous casting operation S100 of producing
15 a steel plate, a rolling operation S200 of rolling the steel
plate produced in the continuous casting operation S100, using
a rolling mill, a cutting operation S300 of cutting the steel
plate rolled in the rolling operation S200 using a cutter, and
a tension applying operation S400 of applying tension to the
20 steel plate present in the rolling mill, having been cut in the
cutting operation S300, using a tension applying unit. In this
case, in the tension applying operation S400, tension may be
applied to the steel plate before the steel plate is cut.
[0069] In further detail, with reference to FIG. 7, the tension
25 applying operation S400 may include a steel plate pressing
Page 21
operation S410 in which the upper roll presses the steel plate
in the tension applying unit, a pressure measuring operation
S420 of measuring a pressure at which the upper roll presses
the steel plate, and an upper roll control operation S430 of
5 controlling movement of the upper roll, such that the pressure
value measured in the pressure measuring operation S420 may
converge with a target pressure value.
[0070] In addition, the tension applying operation may include
a torque measuring operation S440 of measuring a torque value
10 applied to a pressing roll in the tension applying unit; a target
torque setting operation S450 of setting a target torque value
of the pressing roll using the following equation: T = UT × w
× t × r, where t is a target torque value, UT is a level of tensile
stress required to prevent the occurrence of slippage between
15 the steel plate and the upper roll, w is a width of the steel
plate, t is a thickness of the steel plate, and r is a radius
of the pressing roll, and in this case, the pressing roll refers
to both of the upper roll and the lower roll, pressing upper
and lower surfaces of the steel plate to apply tension thereto;
20 and a pressing roll control operation S460 of controlling a
rotation speed of the pressing roll, such that the torque value
measured in the torque measuring operation S440 may converge
with the target torque value.
[0071] In detail, a target pressure value, at which tension
25 may be applied to the steel plate disposed between the upper
Page 22
roll and the lower roll without the occurrence of slippage of
the steel plate therebetween, may be set in S410, and the upper
roll may press the steel plate to obtain the target pressure
value in S430 to apply pressure to the steel plate, such that
5 the steel plate does not slide. Further, a target torque value,
at which tension is applied to the steel plate, may be set using
a level of tensile stress with respect to a material of the steel
plate, a width and thickness of the steel plate, and a radius
of the pressing roll in S440. A rotation speed of the pressing
10 roll may be controlled to converge to the target torque value
in S460, thereby applying tension to the steel plate.
[0072] With reference to FIG. 8, for example, when a torque
value of the pressing roll is lower than a threshold torque value
at which slippage between the pressing roll and the steel plate
15 occurs in an example of S470, the tension applying operation
S400 may further include a target pressure change operation S480
of increasing the target pressure value, such that the torque
value of the pressing roll converges with the target torque
value. For example, the target pressure value may be changed
20 in S480, and the process returns to operation S430 to re-control
movement of the upper roll to converge to the changed target
pressure value in S430.
[0073] In further detail, for example, if slippage of the steel
plate occurs, frictional force between the pressing roll and
25 the steel plate may be decreased, and the torque value measured
Page 23
by the torque measuring unit may be reduced in S470, or may be
zero. Thus, the tension controller may perform controlling to
change the target pressure value to a value greater than a
predetermined value in S480, such that the upper roll may
5 operate to press the steel plate and thus the torque value of
the pressing roll may correspond to a target torque value in
S430.
[0074] With such a configuration, even in the case in which
slippage of the steel plate occurs and thus tension may not be
10 transferred to the steel plate, controlling may be performed
to re-apply tension to the steel plate by determining the case
described above.
[0075] FIG. 9 is a control flowchart schematically
illustrating a method of controlling a steel plate support unit
15 in a method of controlling an endless rolling apparatus
according to an exemplary embodiment.
[0076] Referring to FIG. 9, the method of controlling the steel
plate support unit may include operation S510 of disposing a
steel plate support unit between a plurality of rolling stands
20 of a rolling mill, a steel plate entry sensing operation S520
of sensing entry of the steel plate into the rolling mill, a
support location movement operation S540 of moving a support
roll of the steel plate support unit to a position at the same
height as a height of a lower rolling roll of the rolling mill
25 when movement of the steel plate is sensed in the steel plate
Page 24
entry sensing operation S520 (YES in S530), and a standby
location movement operation S550 of moving the support roll to
a position at a height lower than that of the lower rolling roll
when no movement of the steel plate is performed (NO in S530).
5 [0077] For example, during an endless process in which the
steel plate enters continuously, the support roll may be moved
to a position in which the support roll may support the steel
plate to prevent the steel plate from sagging in the rolling
mill in S540, and in an ending stage of the endless process in
10 which the steel plate does not enter anymore, the support roll
may be moved to a position in which it does not contact the steel
plate in S550.
[0078] In addition, in order to apply tension to the steel plate
as required, the support roll may be controlled to be higher
15 than the lower roll of the rolling mill. The position control
of the support roll as described above may be performed during
a process, as required.
[0079] While exemplary embodiments have been shown and
described above, it will be apparent to those skilled in the
20 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】
An endless rolling apparatus comprising:
a continuous casting apparatus producing a steel plate;
5 a rolling mill disposed behind the continuous casting
apparatus and rolling the steel plate;
a cutter disposed behind the rolling mill and cutting the
steel plate; and
a tension applying unit disposed between the rolling mill
10 and the cutter, and applying tension to a steel plate present
in the rolling mill, having been cut by the cutter.
【Claim 2】
The endless rolling apparatus of claim 1, wherein the
15 tension applying unit comprises:
a base frame;
a pressing roll rotatably disposed on the base frame, and
including an upper roll pressing an upper surface of the steel
plate and a lower roll pressing a lower surface of the steel
20 plate;
a driving motor disposed on the base frame and rotating
the pressing roll; and
a lift unit disposed on the base frame and moving the upper
roll up, and down toward the lower roll.
25
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【Claim 3】
The endless rolling apparatus of claim 2, wherein the lift
unit comprises:
an upper roll support block installed to be slidably moved
5 on the base frame, and supporting the upper roll to be rotated;
and
an upper roll actuator installed on the base frame, and
moving the upper roll via a load connected to the upper roll
support block.
10
【Claim 4】
The endless rolling apparatus of claim 3, wherein the lift
unit comprises:
a pressure measuring unit measuring a pressure at which
15 the upper roll presses the steel plate; and
a tension controller receiving data from the pressure
measuring unit, and controlling operations of the upper roll
actuator, in such a manner that the upper roll presses the steel
plate to obtain a target pressure.
20
【Claim 5】
The endless rolling apparatus of claim 4, wherein the
tension applying unit further comprises a torque measuring unit
measuring a torque value applied to the pressing roll, and
25 the tension controller receives a torque value applied
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to the pressing roll via the torque measuring unit, and controls
a rotation speed of the driving motor, such that the torque value
of the pressing roll converges with a target torque value
derived by the following equation: T = UT × w × t × r, where
5 T is a target torque value, UT is a level of tensile stress
required to prevent slippage between the steel plate and the
upper roll, w is a width of the steel plate, t is a thickness
of the steel plate, and r is a radius of the pressing roll.
10 【Claim 6】
The endless rolling apparatus of claim 5, wherein when
the torque value of the pressing roll is lower than a threshold
torque value at which the slippage between the pressing roll
and the steel plate occurs, the tension controller controls a
15 target pressure value to be increased, such that the torque
value of the pressing roll converges with the target torque
value.
【Claim 7】
20 The endless rolling apparatus of claim 1, wherein the
rolling mill comprises a plurality of rolling stands including
an upper rolling roll and a lower rolling roll,
the endless rolling apparatus further comprising a steel
plate support unit disposed between the plurality of rolling
25 stands to support the steel plate.
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【Claim 8】
The endless rolling apparatus of claim 7, wherein the
steel plate support unit comprises:
5 a frame;
a support roll pressing and supporting one side of the
steel plate; and
a support roll actuator having one side fixed to the frame
and the other side supporting the support roll to be rotated,
10 and moving the support roll to one side of the steel plate.
【Claim 9】
The endless rolling apparatus of claim 8, wherein the
steel plate support unit further comprises:
15 a steel plate detection sensor sensing entry of the steel
plate into the rolling mill; and
a support controller controlling operations of the
support roll actuator, to move the support roll to a position
at the same height as a height of the lower rolling roll of the
20 rolling mill when movement of the steel plate is sensed by the
steel plate detection sensor, and to move the support roll to
a position at a height lower than the height of the lower rolling
roll of the rolling mill when there is no movement of the steel
plate.
25
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【Claim 10】
The endless rolling apparatus of claim 7, wherein in the
rolling mill, an upper rolling roll of any one of the plurality
of the rolling stands is disposed to be spaced apart from the
5 steel plate, such that the upper rolling roll is not in contact
with the steel plate, and
the steel plate support unit is disposed behind the
rolling stand having the upper rolling roll spaced apart from
the steel plate.
10
【Claim 11】
A method of controlling an endless rolling apparatus,
comprising:
performing a continuous casting operation of producing
15 a steel plate;
rolling the steel plate produced in the continuous casting
operation using a rolling mill;
cutting the steel plate rolled in the rolling, using a
cutter; and
20 applying tension to a steel plate present in the rolling
mill, having been cut in the cutting, using a tension applying
unit.
【Claim 12】
25 The method of claim 11, wherein the applying of tension
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comprises:
pressing the steel plate with an upper roll of the tension
applying unit;
measuring a pressure at which the upper roll presses the
5 steel plate; and
controlling movement of the upper roll, such that a
pressure value measured in the measuring of pressure converges
with a target pressure value.
10 【Claim 13】
The method of claim 12, wherein the applying of tension
comprises:
measuring a torque value applied to a pressing roll in
the tension applying unit;
15 setting a target torque value of the pressing roll using
the following equation: T = UT × w × t × r, where T is a target
torque value, UT is a level of tensile stress required to prevent
slippage between the steel plate and the upper roll, w is a width
of the steel plate, t is a thickness of the steel plate, and
20 r is a radius of the pressing roll; and
controlling a rotation speed of the pressing roll, such
that the torque value measured in the measuring of a torque value
converges with the target torque value.
25 【Claim 14】
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The method of claim 13, wherein the applying of tension
further comprises:
changing a target pressure to increase the target pressure
value, such that the torque value of the pressing roll converges
5 with the target torque value, when the torque value of the
pressing roll is lower than a threshold torque value at which
slippage between the pressing roll and the steel plate occurs.
【Claim 15】
10 The method of claim 11, wherein the rolling mill comprises
a plurality of rolling stands including an upper rolling roll
and a lower rolling roll,
the method further comprising supporting the steel plate
with a steel plate support unit disposed between the plurality
15 of rolling stands.
【Claim 16】
The method of claim 15, wherein the supporting of the steel
plate comprises:
20 a steel plate entry sensing operation of sensing entry
of the steel plate into the rolling mill;
a support location movement operation of moving a support
roll of the steel plate support unit to a position at the same
height as a height of the lower rolling roll of the rolling mill
25 when movement of the steel plate is sensed in the steel plate
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entry sensing operation; and
a standby location movement operation of moving the
support roll to a position at a height lower than a height of
the lower rolling roll when there is no movement of the steel
5 plate.