US20110073271A1 - Strip edge shape control apparatus and method in strip casting process - Google Patents
Strip edge shape control apparatus and method in strip casting process Download PDFInfo
- Publication number
- US20110073271A1 US20110073271A1 US12/676,796 US67679608A US2011073271A1 US 20110073271 A1 US20110073271 A1 US 20110073271A1 US 67679608 A US67679608 A US 67679608A US 2011073271 A1 US2011073271 A1 US 2011073271A1
- Authority
- US
- United States
- Prior art keywords
- edge
- strip
- wear
- dams
- upward
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000005266 casting Methods 0.000 title claims abstract description 71
- 238000000034 method Methods 0.000 title claims abstract description 24
- 238000003825 pressing Methods 0.000 claims abstract description 7
- 229910000831 Steel Inorganic materials 0.000 description 17
- 239000010959 steel Substances 0.000 description 17
- 210000003625 skull Anatomy 0.000 description 6
- 238000007711 solidification Methods 0.000 description 6
- 230000008023 solidification Effects 0.000 description 6
- 238000010276 construction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910010293 ceramic material Inorganic materials 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000010485 coping Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/18—Controlling or regulating processes or operations for pouring
- B22D11/181—Controlling or regulating processes or operations for pouring responsive to molten metal level or slag level
- B22D11/185—Controlling or regulating processes or operations for pouring responsive to molten metal level or slag level by using optical means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0622—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0637—Accessories therefor
- B22D11/0648—Casting surfaces
- B22D11/066—Side dams
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/50—Pouring-nozzles
Definitions
- the present invention relates to the control of the edge shape of a strip in strip casting, and more particularly to an apparatus and method for controlling the edge shape of a strip in a twin-roll strip casting process, which improve the quality of the strip by using cameras to photograph the edge portions of the strip being cast by strip casting, analyzing the photographs, and then controlling edge dams according to the edge shape of the strip.
- FIG. 1 is a view showing the construction of a strip casting apparatus according to the prior art. As shown in FIG. 1 , an important process for strip casting generally occurs in a sump between two rolls 1 and 2 that rotate in directions opposite to each other.
- the molten steel When molten steel is supplied to the sump 9 through a submerged entry nozzle 5 from a tundish 4 , the molten steel is solidified between a leader strip and the two rolls within 0.2 seconds and rolled.
- the molten steel, the leader strip that is solidified and a strip that is solidified and follows the leader strip generate roll separating force (RSF).
- the roll force is sensed by a load cell 10 placed at the rear part of the rolls.
- the sides of the two rolls are blocked with ceramic edge dams 8 in order to prevent molten steel from flowing out through the sides of the rolls.
- the solidification capability of molten steel is proportional to the cooling capability of the casting rolls.
- the solidification capability is influenced by the distance between the two rolls, that is, the roll gap, the casting speed (rotating speed) of the rolls, and the height of molten steel in the sump.
- the height of molten steel is measured using a height detection sensor 7 .
- the rolling reduction rate is influenced by the roll gap and the casting speed.
- the roll gap is measured using a distance measuring unit 3 .
- the roll gap is excessively great or if the casting speed is excessively high, the solidification point will decrease below the temperature of the center line of roll nips, such that the roll force gradually decreases, thus causing the non-solidification of molten steel and strip breakdown. In the contrary case, the solidification point will increase, leading to high roll force. Therefore, the roll gap, the casting speed and the roll force are typical casting parameters indicating the solidification properties of the strip.
- the control of the height of molten steel fundamentally requires a high degree of precision and stability. Thus, it is sought to maintain the height of molten steel at a target value starting from immediately after the start of casting. Accordingly, the roll force may seem to result from the relationship between the roll gap and the casting speed.
- the sides of the two rolls are blocked with edge dams made of a ceramic material.
- edge dams made of a ceramic material.
- molten steel can flow into the gap. If molten steel flows into the gap, it will deteriorate the quality of the side of a cast strip, that is, the edge quality of the cast strip, thus reducing the value of the cast strip and abnormally wearing the ceramic material of the edge dam to make normal casting impossible.
- edge dams are oscillated to remove the skull from the edge dams in a very small skull state at the same time at which the skull is produced.
- the oscillation of the edge dams additionally wears the seal plate of the edge dams to form an unnecessarily worn portion between the seal plate of the edge dams and the end face of the rolls, and if molten steel penetrates into and is solidified in that portion, burrs will be formed on a cast strip being produced, thus making the edge shape of the strip poor.
- the efficient control of the edge dams in a twin-roll strip casting process intended for long-term casting is important for producing a high-quality strip and also plays a key role in reducing the production cost by reducing the wear amount of the edge dams.
- the edge quality of a cast strip being produced is one of the most important indices determining the superiority and inferiority of the cast strip product. Such issues must be solved in order to improve quality and productivity, and thus a control method for solving them is required.
- the present invention has been made in order to solve the above-described problems occurring in the prior art, and it is an object of the present invention to provide an apparatus and method for controlling the edge shape of a strip in a twin-roll strip casting process, which comprise observing with a camera a strip being produced in situ, transmitting the observation results to an operation room, analyzing the edge quality of the strip through image processing, and then increasing or decreasing the wear rate and upward shift rate of the edge dams depending on the quality of the strip, thus improving the edge quality of the strip and increasing the life span of the expensive edge dams.
- the present invention provides an apparatus for controlling the edge shape of a strip in a twin-roll strip casting process, the apparatus comprising: an edge dam driving unit which is attached to edge dams attached to both sides of casting rolls so as to control the pressing force of the edge dams against the casting rolls and the upward shift of the edge dams according to the wear and upward shift rate of the edge dams; cameras which are disposed at the strip outlet side of the casting rolls so as to photograph the edge portions of the strip; and a control unit which analyzes the edge shape of the strip from images photographed by the cameras and outputs a signal controlling the wear and upward shift of the edge dams.
- the edge dam driving unit may include: an upward cylinder which is disposed at the upper area of the center of the side opposite the side of the edge dams that comes in contact with the casting rolls, so as to move the edge dams upward; and wear cylinders which are disposed at the left and right sides of the upper portion of the edge dams and at the lower portion of the center of the edge dams so as to press the edge dams against the casting rolls.
- the control unit may include: a main control unit which analyzes the strip edge images photographed by the cameras so as to calculate the wear and upward shift rate of the edge dams; an upward-shift control unit which outputs a signal driving the upward cylinder depending on the upward shift rate and target shift rate of the main control unit; an upward-cylinder servo-valve which drives the upward cylinder according to the driving signal of the upward-shift control unit; a wear control unit which outputs a signal driving the wear cylinders according to the wear rate calculated in the main control unit; and a wear cylinder servo-valve which drives the wear cylinders according to the driving signal of the wear control unit.
- the present invention provides a method for controlling the edge shape of a strip in a twin-roll casting process, the method comprising: a photographing step of photographing images of the edge portions of the strip using cameras disposed at the strip outlet sides of casting rolls; a control signal-producing step of analyzing the strip edge images photographed in the photographing step and outputting a control signal for a wear and upward shift rate; and an edge dam control step of controlling the wear and upward shift of edge dams according to the control signal output in the control signal-producing step.
- the control signal-producing step may include: an edge analysis step of calculating the burr thickness of the edge dams and the length of an edge fin; a step of outputting a signal for maintaining the edge dams at a default wear and upward shift rate set in the normal state of the edge dams, if the edge analysis step shows a burr thickness of less than 1 mm and no existence of an edge fin; a step of outputting a signal for additionally applying a wear and upward shift rate of 1 ⁇ m per m of the strip to the default wear and upward shift rate, if the edge analysis step shows a burr thickness of more than 1 mm but less than 5 mm and an edge fin length of less than 1 cm; and a step of outputting a signal for additionally applying a wear and upward shift rate of 1.5 ⁇ m per m of the strip to the default wear and upward shift rate, if the edge analysis step shows a burr thickness of more than 5 mm and an edge fin length of more than 1 cm.
- the edge dam control step may include the steps of: re-analyzing the edge portions of the strip after performing the control of the edge dams according to the signal output in the control signal-producing step; and controlling the edge dams so as to return to the default value of the edge dam wear and upward shift rate, if the edge portions are normal.
- the default value of the wear and upward shift rate of the edge dams may be set within the range of 0.5 to 5 ⁇ m per m of the strip.
- control signal-producing step and the edge dam control step may be manually carried out.
- the present invention provides the effect of improving the quality and productivity of a strip in a twin-roll strip casting process.
- the present invention provides the effect of allowing an expensive edge dam to be used for a long period of time.
- the present invention provides the effects of suppressing the generation of strip scraps and extending the life span of an edge dam, thus reducing production cost.
- FIG. 1 is a view showing the construction of a strip casting apparatus according to the present invention.
- FIG. 2 is a block diagram of an apparatus for controlling the edge shape of a strip in a twin-roll strip casting process (hereinafter referred to as “edge shape control apparatus”) according to an embodiment of the present invention.
- FIG. 3 is a view showing the position of cylinders attached to an edge dam.
- FIG. 4 is a flowchart showing the processing procedure of the inventive method for controlling the edge shape of a strip in a twin-roll strip casting process.
- FIG. 2 is a block diagram showing the construction of an apparatus for controlling the edge shape of a strip in a twin-roll strip casting process (hereinafter referred to as “edge shape control apparatus”) according to an embodiment of the present invention
- FIG. 3 is a view showing the position of cylinders attached to an edge dam.
- the edge shape control apparatus comprises an edge dam driving unit 100 which is attached to both sides of casting rolls so as to control the pressing force of the edge dams against the casting rolls and the upward shift of the edge dams depending on the wear and upward shift rate of the edge dams; cameras 200 which are disposed at both sides of the edge dams at the outlet side of the casting rolls 12 through which a strip 12 is discharged, the cameras serving to photograph the edge portion of the strip; and a control unit 300 which analyzes the images photographed by the cameras 200 so as to analyze the burr thickness and edge fin length of the edge portion and outputs to the edge dam driving unit 100 a signal controlling the wear and upward shift rate of the edge dams according to the thickness of a burr and the length of an edge fin.
- the edge dam driving unit 100 comprises: an upward cylinder 101 which is disposed at the upper area of the center of the side opposite the side of the edge dams that comes in contact with the casting rolls, so as to move the edge dam upward; and a wear cylinder 102 which is disposed horizontally at the back side of the edge dams so as to control the forward and backward movement of the edge dams 100 with respect to the casting rolls.
- the upward cylinder 101 which is disposed at the upper area is connected to the upper portion 111 of the back side of the edge dam 110 as shown in FIG. 3 .
- the wear cylinder 102 is disposed at the back side of the edge dam 110 in order to move the edge darn forward and backward with respect to the casting rolls.
- the wear cylinder 102 may also be disposed at the back side of the edge dams at each of both sides 112 and 113 of the upper portion of the edge dams and the lower portion 114 of the center of the edge dams.
- the cameras 200 are disposed at a strip outlet side through which a cast strip is discharged.
- the cameras photograph the edge portion of the strip 12 with a resolution allowing the edge portion to be analyzed up to a millimeter scale, and output the photographed images to the control unit 300 .
- the control unit 300 comprises: a main control unit 310 which analyzes the strip edge images photographed by the cameras 200 so as to calculate the wear and upward shift rate of the edge dams; an upward-shift control unit 320 which outputs a signal driving the upward cylinder 101 depending on the upward shift rate and target shift rate of the main control unit 310 ; a first DA converter 321 which converts the driving signal of the upward-shift control unit 320 to an analog signal; a servo-valve 322 which drives the upward cylinder 101 according to the output signal of the first DA converter 321 ; a first distance measuring sensor 323 which is disposed at each of the casting rolls 1 and 2 so as to sense the upward moving distance of the edge dam 110 ; a first AD converter 324 which converts the output signal of the first distance measuring sensor 323 to a digital signal and then outputs the digital signal to the upward shift control unit 320 ; a wear control unit 330 which outputs a signal driving the wear cylinder 102 according to the edge dam wear rate and target wear rate of the
- FIG. 4 is a flowchart showing the procedures of the inventive method for controlling the edge shape of a strip in a twin-roll strip casting process.
- the edge shape control apparatus of the present invention performs the control of the pressing force of the edge dam against the casting rolls and the upward shift of the edge dam to the default set wear and upward shift rate of the edge dam while performing casting as in the prior art.
- the default set wear and upward shift rate of the edge dam can be set within the range of 0.5-5 ⁇ m per m of a strip.
- the cameras 200 continuously photograph images of the edge portions of the strip being cast and discharged and output the images to the control unit 300 (S 1 ).
- control unit 300 analyzes the strip edge images photographed by the cameras 200 and determines whether the state of the strip edge is poor (S 2 and S 3 ).
- control unit 300 produces and outputs a signal for controlling the wear and upward shift of the edge dams.
- An example of the wear and upward shift rate of the edge dams will now be described.
- the main control unit 310 outputs a signal maintaining the edge dams at the wear and upward shift rate set at a default value in the normal state of the edge dams.
- the wear and upward shift rate set at a default value in the normal state of the edge dams can be set within the range of 0.5 to 5 ⁇ m per m of the strip as described above.
- the main control unit 310 If the burr thickness of the strip edge is more than 1 mm but less than 5 mm and the length of the edge fin is less than 1 cm, the main control unit 310 outputs a signal for additionally applying a wear and upward shift rate of 1 ⁇ m per m of the strip to the default set value. Then, if the burr thickness of the strip edge is more than 5 mm and the length of the edge fin is more than 1 cm, the main control unit 310 outputs a signal for additionally applying a wear and upward shift rate of 1.5 ⁇ m per m of the strip to the default set value.
- Such output signals of the main control unit 310 are input into the shift control unit 320 and the wear control unit 330 so as to drive the upward cylinder 101 and wear cylinder 102 connected to the back side of the edge dam 110 , thus controlling the pressing force of the edge dam against the casting rolls and the upward shift of the edge dam (S 4 ).
- the edge portions of the strip 12 which is produced while controlling the wear and upward shift rate of the edge dam 110 are continuously photographed with the cameras 200 in order to determine whether the state of the edge portions has been restored to the normal state (S 5 ).
- the control unit 300 continually controls the wear and upward shift of the edge dam according to the edge dam wear and upward shift rate output in step S 4 . However, if the state of the edge portions has returned to the normal state, the edge dam wear and upward shift rate of the edge dam returns to the initially set default value, and the pressing force of the edge dam against the casting rolls and the upward shift rate of the edge dam are controlled (S 6 ).
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Abstract
Disclosed herein are an apparatus and method for controlling the edge shape of a strip in a twin-roll strip casting process, which improve the quality of the strip by using cameras to photograph the edge portions of the strip being cast by strip casting, analyzing the photographs, and then controlling edge dams according to the edge shape of the strip. The apparatus comprises: an edge dam driving unit which is attached to edge dams attached to both sides of casting rolls so as to control the pressing force of the edge dams against the casting rolls and the upward shift of the edge dams according to the wear and upward shift rate of the edge dams; cameras which are disposed at the strip outlet side of the casting rolls so as to photograph the edge portions of the strip; and a control unit which analyzes the edge shape of the strip from images photographed by the cameras and outputs a signal controlling the wear and upward shift of the edge dams.
Description
- The present invention relates to the control of the edge shape of a strip in strip casting, and more particularly to an apparatus and method for controlling the edge shape of a strip in a twin-roll strip casting process, which improve the quality of the strip by using cameras to photograph the edge portions of the strip being cast by strip casting, analyzing the photographs, and then controlling edge dams according to the edge shape of the strip.
-
FIG. 1 is a view showing the construction of a strip casting apparatus according to the prior art. As shown inFIG. 1 , an important process for strip casting generally occurs in a sump between tworolls - When molten steel is supplied to the sump 9 through a submerged
entry nozzle 5 from a tundish 4, the molten steel is solidified between a leader strip and the two rolls within 0.2 seconds and rolled. Herein, the molten steel, the leader strip that is solidified and a strip that is solidified and follows the leader strip generate roll separating force (RSF). The roll force is sensed by aload cell 10 placed at the rear part of the rolls. - The sides of the two rolls are blocked with ceramic edge dams 8 in order to prevent molten steel from flowing out through the sides of the rolls.
- The solidification capability of molten steel is proportional to the cooling capability of the casting rolls. In addition, the solidification capability is influenced by the distance between the two rolls, that is, the roll gap, the casting speed (rotating speed) of the rolls, and the height of molten steel in the sump. The height of molten steel is measured using a height detection sensor 7. In general, when molten steel solidifies, it generates roll force between the rolls. The rolling reduction rate is influenced by the roll gap and the casting speed. The roll gap is measured using a distance measuring unit 3. For example, if the roll gap is excessively great or if the casting speed is excessively high, the solidification point will decrease below the temperature of the center line of roll nips, such that the roll force gradually decreases, thus causing the non-solidification of molten steel and strip breakdown. In the contrary case, the solidification point will increase, leading to high roll force. Therefore, the roll gap, the casting speed and the roll force are typical casting parameters indicating the solidification properties of the strip.
- The control of the height of molten steel fundamentally requires a high degree of precision and stability. Thus, it is sought to maintain the height of molten steel at a target value starting from immediately after the start of casting. Accordingly, the roll force may seem to result from the relationship between the roll gap and the casting speed.
- In order to prevent molten steel from flowing out through the sides of the two rolls during casting in a twin-roll strip casting apparatus, the sides of the two rolls are blocked with edge dams made of a ceramic material. In this case, even though there is an interval of only a few tens of micrometers (μm) between the sides of the rolls and the edge dams, molten steel can flow into the gap. If molten steel flows into the gap, it will deteriorate the quality of the side of a cast strip, that is, the edge quality of the cast strip, thus reducing the value of the cast strip and abnormally wearing the ceramic material of the edge dam to make normal casting impossible.
- Moreover, in many cases, a skull that almost inevitably occurs due to the temperature drop of molten steel and the surrounding devices during casting is incorporated between the sides of the rolls and the edge dams, and thus the seal plate of the edge dam is damaged. For this reason, an edge fin occurs at the edge portion of a cast strip being produced, leading to deterioration in the quality of the cast strip.
- In order to prevent the production of this skull, a method is used in which the edge dams are oscillated to remove the skull from the edge dams in a very small skull state at the same time at which the skull is produced. However, the oscillation of the edge dams additionally wears the seal plate of the edge dams to form an unnecessarily worn portion between the seal plate of the edge dams and the end face of the rolls, and if molten steel penetrates into and is solidified in that portion, burrs will be formed on a cast strip being produced, thus making the edge shape of the strip poor.
- The efficient control of the edge dams in a twin-roll strip casting process intended for long-term casting is important for producing a high-quality strip and also plays a key role in reducing the production cost by reducing the wear amount of the edge dams. At the same time, the edge quality of a cast strip being produced is one of the most important indices determining the superiority and inferiority of the cast strip product. Such issues must be solved in order to improve quality and productivity, and thus a control method for solving them is required.
- According to studies on edge dam control conducted through casting experience in a twin-roll strip casting apparatus so far, a method which can be used by operators when the edge quality of a cast strip is bad is to control the wear rate and upward shift rate. In addition, when the ceramic material of the edge dams is broken during casting, the only method for coping with this situation is to stop the casting process.
- Accordingly, it is very important for operators to closely examine all data related to edge dam control during casting so as to prevent reaching such an extreme situation. Thus, it is very important during casting to immediately observe and analyze the quality of a cast strip being produced and to reflect the analysis results on the control of the edge dams.
- However, much time is required for an operator to visually analyze the strip coming out of a casting machine, to return to an edge dam controller in an operation room and to analyze the analysis results. Due to this time delay, molten steel and a skull are incorporated between the sides of the rolls and the edge dams, damaging the seal plate of the edge dams, so that the quality of the cast strip becomes poor and the life span of the expensive edge dams is shortened.
- The present invention has been made in order to solve the above-described problems occurring in the prior art, and it is an object of the present invention to provide an apparatus and method for controlling the edge shape of a strip in a twin-roll strip casting process, which comprise observing with a camera a strip being produced in situ, transmitting the observation results to an operation room, analyzing the edge quality of the strip through image processing, and then increasing or decreasing the wear rate and upward shift rate of the edge dams depending on the quality of the strip, thus improving the edge quality of the strip and increasing the life span of the expensive edge dams.
- To achieve the above object, the present invention provides an apparatus for controlling the edge shape of a strip in a twin-roll strip casting process, the apparatus comprising: an edge dam driving unit which is attached to edge dams attached to both sides of casting rolls so as to control the pressing force of the edge dams against the casting rolls and the upward shift of the edge dams according to the wear and upward shift rate of the edge dams; cameras which are disposed at the strip outlet side of the casting rolls so as to photograph the edge portions of the strip; and a control unit which analyzes the edge shape of the strip from images photographed by the cameras and outputs a signal controlling the wear and upward shift of the edge dams.
- In the present invention, the edge dam driving unit may include: an upward cylinder which is disposed at the upper area of the center of the side opposite the side of the edge dams that comes in contact with the casting rolls, so as to move the edge dams upward; and wear cylinders which are disposed at the left and right sides of the upper portion of the edge dams and at the lower portion of the center of the edge dams so as to press the edge dams against the casting rolls.
- The control unit may include: a main control unit which analyzes the strip edge images photographed by the cameras so as to calculate the wear and upward shift rate of the edge dams; an upward-shift control unit which outputs a signal driving the upward cylinder depending on the upward shift rate and target shift rate of the main control unit; an upward-cylinder servo-valve which drives the upward cylinder according to the driving signal of the upward-shift control unit; a wear control unit which outputs a signal driving the wear cylinders according to the wear rate calculated in the main control unit; and a wear cylinder servo-valve which drives the wear cylinders according to the driving signal of the wear control unit.
- In another aspect, the present invention provides a method for controlling the edge shape of a strip in a twin-roll casting process, the method comprising: a photographing step of photographing images of the edge portions of the strip using cameras disposed at the strip outlet sides of casting rolls; a control signal-producing step of analyzing the strip edge images photographed in the photographing step and outputting a control signal for a wear and upward shift rate; and an edge dam control step of controlling the wear and upward shift of edge dams according to the control signal output in the control signal-producing step.
- In the method of the present invention, the control signal-producing step may include: an edge analysis step of calculating the burr thickness of the edge dams and the length of an edge fin; a step of outputting a signal for maintaining the edge dams at a default wear and upward shift rate set in the normal state of the edge dams, if the edge analysis step shows a burr thickness of less than 1 mm and no existence of an edge fin; a step of outputting a signal for additionally applying a wear and upward shift rate of 1 μm per m of the strip to the default wear and upward shift rate, if the edge analysis step shows a burr thickness of more than 1 mm but less than 5 mm and an edge fin length of less than 1 cm; and a step of outputting a signal for additionally applying a wear and upward shift rate of 1.5 μm per m of the strip to the default wear and upward shift rate, if the edge analysis step shows a burr thickness of more than 5 mm and an edge fin length of more than 1 cm.
- Also, the edge dam control step may include the steps of: re-analyzing the edge portions of the strip after performing the control of the edge dams according to the signal output in the control signal-producing step; and controlling the edge dams so as to return to the default value of the edge dam wear and upward shift rate, if the edge portions are normal.
- In addition, the default value of the wear and upward shift rate of the edge dams may be set within the range of 0.5 to 5 μm per m of the strip.
- Furthermore, the control signal-producing step and the edge dam control step may be manually carried out.
- The present invention provides the effect of improving the quality and productivity of a strip in a twin-roll strip casting process.
- In addition, the present invention provides the effect of allowing an expensive edge dam to be used for a long period of time.
- Namely, the present invention provides the effects of suppressing the generation of strip scraps and extending the life span of an edge dam, thus reducing production cost.
-
FIG. 1 is a view showing the construction of a strip casting apparatus according to the present invention. -
FIG. 2 is a block diagram of an apparatus for controlling the edge shape of a strip in a twin-roll strip casting process (hereinafter referred to as “edge shape control apparatus”) according to an embodiment of the present invention. -
FIG. 3 is a view showing the position of cylinders attached to an edge dam. -
FIG. 4 is a flowchart showing the processing procedure of the inventive method for controlling the edge shape of a strip in a twin-roll strip casting process. - Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
-
FIG. 2 is a block diagram showing the construction of an apparatus for controlling the edge shape of a strip in a twin-roll strip casting process (hereinafter referred to as “edge shape control apparatus”) according to an embodiment of the present invention, andFIG. 3 is a view showing the position of cylinders attached to an edge dam. - As shown in
FIG. 2 , the edge shape control apparatus comprises an edgedam driving unit 100 which is attached to both sides of casting rolls so as to control the pressing force of the edge dams against the casting rolls and the upward shift of the edge dams depending on the wear and upward shift rate of the edge dams;cameras 200 which are disposed at both sides of the edge dams at the outlet side of thecasting rolls 12 through which astrip 12 is discharged, the cameras serving to photograph the edge portion of the strip; and acontrol unit 300 which analyzes the images photographed by thecameras 200 so as to analyze the burr thickness and edge fin length of the edge portion and outputs to the edge dam driving unit 100 a signal controlling the wear and upward shift rate of the edge dams according to the thickness of a burr and the length of an edge fin. - In the above-described construction, the edge
dam driving unit 100 comprises: anupward cylinder 101 which is disposed at the upper area of the center of the side opposite the side of the edge dams that comes in contact with the casting rolls, so as to move the edge dam upward; and awear cylinder 102 which is disposed horizontally at the back side of the edge dams so as to control the forward and backward movement of theedge dams 100 with respect to the casting rolls. Herein, theupward cylinder 101 which is disposed at the upper area is connected to theupper portion 111 of the back side of theedge dam 110 as shown inFIG. 3 . Also, thewear cylinder 102 is disposed at the back side of theedge dam 110 in order to move the edge darn forward and backward with respect to the casting rolls. As shown inFIG. 3 , thewear cylinder 102 may also be disposed at the back side of the edge dams at each of bothsides lower portion 114 of the center of the edge dams. - The
cameras 200 are disposed at a strip outlet side through which a cast strip is discharged. The cameras photograph the edge portion of thestrip 12 with a resolution allowing the edge portion to be analyzed up to a millimeter scale, and output the photographed images to thecontrol unit 300. - Then, the control unit 300 comprises: a main control unit 310 which analyzes the strip edge images photographed by the cameras 200 so as to calculate the wear and upward shift rate of the edge dams; an upward-shift control unit 320 which outputs a signal driving the upward cylinder 101 depending on the upward shift rate and target shift rate of the main control unit 310; a first DA converter 321 which converts the driving signal of the upward-shift control unit 320 to an analog signal; a servo-valve 322 which drives the upward cylinder 101 according to the output signal of the first DA converter 321; a first distance measuring sensor 323 which is disposed at each of the casting rolls 1 and 2 so as to sense the upward moving distance of the edge dam 110; a first AD converter 324 which converts the output signal of the first distance measuring sensor 323 to a digital signal and then outputs the digital signal to the upward shift control unit 320; a wear control unit 330 which outputs a signal driving the wear cylinder 102 according to the edge dam wear rate and target wear rate of the main control unit 310; a second DA converter 331 which converts the driving signal of the wear control unit 330 to an analog signal; a wear cylinder servo-valve 332 which drives the wear cylinder 102 according to the output signal of the second DA converter 331; a second distance measuring sensor 333 which is disposed at each of the casting rolls 1 and 2 so as to sense the distance of the edge dam 110 moved with respect to the casting rolls; and a second AD converter 334 which converts the output signal of the second distance measuring sensor 333 to a digital signal and then outputs the digital signal to the wear control unit 330.
-
FIG. 4 is a flowchart showing the procedures of the inventive method for controlling the edge shape of a strip in a twin-roll strip casting process. - Hereinafter, the inventive method for controlling the edge shape of a strip in a twin-roll strip casting process will be described with reference to
FIGS. 2 to 4 . The edge shape control apparatus of the present invention performs the control of the pressing force of the edge dam against the casting rolls and the upward shift of the edge dam to the default set wear and upward shift rate of the edge dam while performing casting as in the prior art. Herein, the default set wear and upward shift rate of the edge dam can be set within the range of 0.5-5 μm per m of a strip. - Herein, the
cameras 200 continuously photograph images of the edge portions of the strip being cast and discharged and output the images to the control unit 300 (S1). - Then, the
control unit 300 analyzes the strip edge images photographed by thecameras 200 and determines whether the state of the strip edge is poor (S2 and S3). - If the state of the edge is determined to be poor, the
control unit 300 produces and outputs a signal for controlling the wear and upward shift of the edge dams. An example of the wear and upward shift rate of the edge dams will now be described. - If the burr thickness of the edge portion is less than 1 mm and no edge fin exists in the strip images photographed by the
cameras 200, themain control unit 310 outputs a signal maintaining the edge dams at the wear and upward shift rate set at a default value in the normal state of the edge dams. Herein, the wear and upward shift rate set at a default value in the normal state of the edge dams can be set within the range of 0.5 to 5 μm per m of the strip as described above. - If the burr thickness of the strip edge is more than 1 mm but less than 5 mm and the length of the edge fin is less than 1 cm, the
main control unit 310 outputs a signal for additionally applying a wear and upward shift rate of 1 μm per m of the strip to the default set value. Then, if the burr thickness of the strip edge is more than 5 mm and the length of the edge fin is more than 1 cm, themain control unit 310 outputs a signal for additionally applying a wear and upward shift rate of 1.5 μm per m of the strip to the default set value. Such output signals of themain control unit 310 are input into theshift control unit 320 and thewear control unit 330 so as to drive theupward cylinder 101 and wearcylinder 102 connected to the back side of theedge dam 110, thus controlling the pressing force of the edge dam against the casting rolls and the upward shift of the edge dam (S4). - Then, the edge portions of the
strip 12 which is produced while controlling the wear and upward shift rate of theedge dam 110 are continuously photographed with thecameras 200 in order to determine whether the state of the edge portions has been restored to the normal state (S5). - If the state of the edge portions has not been restored to the normal state, the
control unit 300 continually controls the wear and upward shift of the edge dam according to the edge dam wear and upward shift rate output in step S4. However, if the state of the edge portions has returned to the normal state, the edge dam wear and upward shift rate of the edge dam returns to the initially set default value, and the pressing force of the edge dam against the casting rolls and the upward shift rate of the edge dam are controlled (S6). - In addition, the above-described processing procedure is repeated during the casting process, and when the casting process has ended, the processing procedure is ended (S7).
Claims (7)
1. An apparatus for controlling the edge shape of a strip in a twin-roll casting process, the apparatus comprising:
an edge dam driving unit which is attached to edge dams attached to both sides of casting rolls so as to control the pressing force of the edge dams against the casting rolls and the upward shift of the edge dams according to the wear and upward shift rate of the edge dams;
cameras which are disposed at the strip outlet side of the casting rolls so as to photograph the edge portions of the strip; and
a control unit which analyzes the edge shape of the strip from images photographed by the cameras and outputs a signal controlling the wear and upward shift of the edge dams.
2. The apparatus of claim 1 , wherein the edge dam driving unit comprises:
an upward cylinder which is disposed at the upper area of the center of the side opposite the side of the edge dams that comes in contact with the casting rolls, so as to move the edge dams upward; and
wear cylinders which are disposed at the left and right sides of the upper portion of the edge dams and at the lower portion of the center of the edge dams so as to press the edge dams against the casting rolls.
3. The apparatus of claim 2 , wherein the control unit comprises:
a main control unit which analyzes the strip edge images photographed by the cameras so as to calculate the wear and upward shift rate of the edge dams;
an upward-shift control unit which outputs a signal driving the upward cylinder depending on the upward shift rate and target shift rate of the main control unit;
an upward-cylinder servo-valve which drives the upward cylinder according to the driving signal of the upward-shift control unit;
a wear control unit which outputs a signal driving the wear cylinders according to the wear rate calculated in the main control unit; and
a wear cylinder servo-valve which drives the wear cylinders according to the driving signal of the wear control unit.
4. A method for controlling the edge shape of a strip in a twin-roll casting process, the method comprising:
a photographing step of photographing the images of edge portions of the strip using cameras disposed at the strip outlet sides of casting rolls;
a control signal-producing step of analyzing the strip edge images photographed in the photographing step and outputting a control signal for a wear and upward shift rate; and
an edge dam control step of controlling the wear and upward shift of edge dams according to the control signal output in the control signal-producing step.
5. The method of claim 4 , wherein the control signal-producing step comprises:
an edge analysis step of calculating the burr thickness of the edge dams and the length of an edge fin;
a step of outputting a signal for maintaining the edge dams at a default wear and upward shift rate set in the normal state of the edge dams, if the edge analysis step shows a burr thickness of less than 1 mm and no existence of the edge fin;
a step of outputting a signal for additionally applying a wear and upward shift rate of 1 μm per m of the strip to the default wear and upward shift rate, if the edge analysis step shows a burr thickness of more than 1 mm but less than 5 mm and an edge fin length of less than 1 cm; and
a step of outputting a signal for additionally applying a wear and upward shift rate of 1.5 μm per m of the strip to the default wear and upward shift rate, if the edge analysis step shows a burr thickness of more than 5 mm and an edge fin length of more than 1 cm.
6. The method of claim 4 , wherein the edge dam control step comprises the steps of:
re-analyzing the edge portions of the strip after performing the control of the edge dams according to the signal output in the control signal-producing step; and
controlling the edge dams so as to return to the default value of the edge dam wear and upward shift rate, if the edge portions are normal.
7. The method of claim 5 or 6 , wherein the default value of the wear and upward shift rate is set within the range of 0.5 to 5 μm per m of the strip.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020070097701A KR100977783B1 (en) | 2007-09-28 | 2007-09-28 | Strip edge shape control apparatus and method in strip casting process |
KR10-2007-0097701 | 2007-09-28 | ||
PCT/KR2008/005697 WO2009041777A2 (en) | 2007-09-28 | 2008-09-25 | Strip edge shape control apparatus and method in strip casting process |
Publications (1)
Publication Number | Publication Date |
---|---|
US20110073271A1 true US20110073271A1 (en) | 2011-03-31 |
Family
ID=40512022
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/676,796 Abandoned US20110073271A1 (en) | 2007-09-28 | 2008-09-25 | Strip edge shape control apparatus and method in strip casting process |
Country Status (7)
Country | Link |
---|---|
US (1) | US20110073271A1 (en) |
EP (1) | EP2193000A4 (en) |
JP (1) | JP5127926B2 (en) |
KR (1) | KR100977783B1 (en) |
CN (1) | CN101801562B (en) |
AU (1) | AU2008304045B2 (en) |
WO (1) | WO2009041777A2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9649684B2 (en) | 2014-07-24 | 2017-05-16 | Posco | Twin roll strip casting method |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR101243117B1 (en) * | 2009-12-17 | 2013-03-12 | 주식회사 포스코 | Method for controlling edge dam in twin roll strip casting process |
CN102198495B (en) * | 2010-03-26 | 2013-05-29 | 宝山钢铁股份有限公司 | Method for controlling side seal of twin roll thin strip casting and device |
JP5837758B2 (en) | 2011-04-27 | 2015-12-24 | キャストリップ・リミテッド・ライアビリティ・カンパニー | Twin roll casting apparatus and control method thereof |
KR101309920B1 (en) * | 2011-12-13 | 2013-09-17 | 주식회사 포스코 | Apparatus and method of measuring edge dam |
KR101372681B1 (en) | 2011-12-21 | 2014-03-10 | 주식회사 포스코 | Method and system for reducing edge bulging in twin roll strip casting process |
JP5924246B2 (en) * | 2012-11-22 | 2016-05-25 | トヨタ自動車株式会社 | Pull-up continuous casting apparatus, pull-up continuous casting method, and solidification interface detection apparatus |
CN105848807B (en) * | 2013-12-23 | 2018-12-11 | Posco公司 | Slab scafing device and its control method |
CN112247085B (en) * | 2020-09-07 | 2021-10-19 | 东北大学 | Control method and device for thin strip continuous casting side seal pressing mechanism |
CN115519096B (en) * | 2022-09-19 | 2023-08-01 | 江苏中科云控智能工业装备有限公司 | Die casting deburring equipment state detection system and method based on big data |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6296496B1 (en) * | 2000-08-16 | 2001-10-02 | Hon Hai Precision Ind. Co., Ltd. | Electrical connector and method for attaching the same to a printed circuit board |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6210936U (en) * | 1985-07-04 | 1987-01-23 | ||
JPH0232347U (en) * | 1988-08-23 | 1990-02-28 | ||
JPH04322843A (en) * | 1991-04-20 | 1992-11-12 | Nippon Steel Corp | Method and device for controlling pressing force to side weir in continuous caster for cast strip |
JPH05161945A (en) * | 1991-12-13 | 1993-06-29 | Nippon Steel Corp | Twin drum type strip continuous casting method |
JP3021170B2 (en) * | 1992-03-24 | 2000-03-15 | 三菱重工業株式会社 | Twin-drum continuous casting machine |
KR100333070B1 (en) * | 1997-12-20 | 2002-10-18 | 주식회사 포스코 | Method for controlling position of edge dams in twin roll type strip caster |
JP3540980B2 (en) * | 1999-07-16 | 2004-07-07 | 新日本製鐵株式会社 | Twin-drum continuous casting method and apparatus |
JP2001058244A (en) * | 1999-08-24 | 2001-03-06 | Nippon Steel Corp | Detection of worn quantity of side weir in twin roll continuous casting equipment, detecting instrument of worn quantity of side weir, method for controlling position of side weir and controller of position of side weir |
JP2001205400A (en) * | 2000-01-26 | 2001-07-31 | Nippon Steel Corp | Method for twin-drum type continuous casting of strip and casting device |
KR100554734B1 (en) | 2001-08-24 | 2006-02-24 | 주식회사 포스코 | A methof for detecting edge skull in strip casting process |
KR100605709B1 (en) * | 2001-12-21 | 2006-08-01 | 주식회사 포스코 | Hot band control method and apparatus using brush roll in the strip casting process |
KR100584751B1 (en) * | 2001-12-22 | 2006-05-30 | 주식회사 포스코 | An apparatus for controlling gas layer thickness on the surface of casting roll in twin roll strip caster |
JP3747007B2 (en) * | 2002-04-09 | 2006-02-22 | 新日本製鐵株式会社 | Twin drum type continuous casting method and apparatus |
KR101059204B1 (en) * | 2004-06-28 | 2011-08-24 | 주식회사 포스코 | Automatic control of scull removal using image processing |
-
2007
- 2007-09-28 KR KR1020070097701A patent/KR100977783B1/en active IP Right Grant
-
2008
- 2008-09-25 EP EP08833282.0A patent/EP2193000A4/en not_active Withdrawn
- 2008-09-25 AU AU2008304045A patent/AU2008304045B2/en not_active Ceased
- 2008-09-25 US US12/676,796 patent/US20110073271A1/en not_active Abandoned
- 2008-09-25 JP JP2010522828A patent/JP5127926B2/en not_active Expired - Fee Related
- 2008-09-25 WO PCT/KR2008/005697 patent/WO2009041777A2/en active Application Filing
- 2008-09-25 CN CN2008801074772A patent/CN101801562B/en not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6296496B1 (en) * | 2000-08-16 | 2001-10-02 | Hon Hai Precision Ind. Co., Ltd. | Electrical connector and method for attaching the same to a printed circuit board |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9649684B2 (en) | 2014-07-24 | 2017-05-16 | Posco | Twin roll strip casting method |
Also Published As
Publication number | Publication date |
---|---|
AU2008304045B2 (en) | 2011-10-06 |
CN101801562A (en) | 2010-08-11 |
WO2009041777A3 (en) | 2009-06-11 |
JP5127926B2 (en) | 2013-01-23 |
AU2008304045A1 (en) | 2009-04-02 |
WO2009041777A2 (en) | 2009-04-02 |
EP2193000A4 (en) | 2015-01-28 |
KR100977783B1 (en) | 2010-08-24 |
CN101801562B (en) | 2013-03-06 |
EP2193000A2 (en) | 2010-06-09 |
KR20090032443A (en) | 2009-04-01 |
JP2010536580A (en) | 2010-12-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20110073271A1 (en) | Strip edge shape control apparatus and method in strip casting process | |
CN102198495B (en) | Method for controlling side seal of twin roll thin strip casting and device | |
JP5976087B2 (en) | Damage prevention device for casting roll in thin plate manufacturing equipment. | |
JP2010536580A5 (en) | ||
KR100779571B1 (en) | Method of controlling for casting roll gap in strip caster | |
KR100605709B1 (en) | Hot band control method and apparatus using brush roll in the strip casting process | |
JP2007245168A (en) | Method and apparatus for detecting completion of solidification in continuous casting, and method and apparatus for continuous casting | |
KR101500102B1 (en) | Apparatus and method of controlling wear of edgedam in twin roll strip casting process | |
JPH0847762A (en) | Continuous casting method | |
KR100954797B1 (en) | Method of edge dam load controlling in twin roll strip caster | |
KR101130719B1 (en) | Method for sensing the melt level | |
JP6950838B2 (en) | Manufacture method and control device for slabs | |
KR100841774B1 (en) | Control method for edge dam in twin roll strip caster | |
KR102045682B1 (en) | Twin roll type thin plate manufacturing apparatus and method | |
KR101186578B1 (en) | Structure of edge dam in twin roll strip caster | |
KR101186584B1 (en) | Method measuring edge skull in twin roll strip casting process | |
KR100733365B1 (en) | Method for detecting skull using load cell | |
KR100971966B1 (en) | System And Method For Controlling Weight Of Turndish At Twin Roll Strip Caster | |
KR101568491B1 (en) | Apparatus and method for controlling edge dam in twin roll strip casting process | |
JP2004306053A (en) | Light rolling reduction method and light rolling reduction device for slab in continuous casting | |
KR101243258B1 (en) | Apparatus for controlling oscillation of edge dam of twin roll strip casting process and method therefor | |
KR20040019727A (en) | The control method of driven roll pressure in continuous casting equipments | |
JPH08141715A (en) | Continuous casting apparatus and continuous casting method | |
KR19990054413A (en) | Control method of thin plate solidification amount for twin roll thin plate manufacturing device | |
KR20120073656A (en) | Device and method for detecting breakout in a continuous die casting process |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: POSCO, KOREA, REPUBLIC OF Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KIM, YOON-HA;KIM, SANG-HOON;CHEONG, HAN-NAM;REEL/FRAME:024049/0094 Effective date: 20100208 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |