WO2008082160A1

WO2008082160A1 - Apparatus for manufacturing metal strips

Info

Publication number: WO2008082160A1
Application number: PCT/KR2007/006904
Authority: WO
Inventors: Dong-Kyun Choo; Sang-Ho Ahn; Woo-Jin Park; In-Ho Jung; In-Jun Kim; WonKyu BANG; Hwan-Jin Sung
Original assignee: Posco; Research Institute Of Technology Science & Technology
Priority date: 2006-12-29
Filing date: 2007-12-27
Publication date: 2008-07-10
Also published as: TWI374065B; TWI374064B; TW201221247A; TW200911414A

Abstract

The present invention relates to a thin plate casting device. The thin plate casting device includes a pair of casting rollers facing each other, a nozzle assembly, at least one brush assembly, and a driver. The nozzle assembly is positioned at an inflow area formed between the pair of casting rollers to supply a molten metal. The at least one brush assembly includes a rotational shaft that is capable of moving and a brush fixed to the rotational shaft. In addition, the brush assembly is positioned at a location corresponding to the casting roller.

Description

APPARATUS FOR MANUFACTURING MtTAL STKlFS

Technical Field

The present invention relates to a thin plate casting device, and more particularly to a thin plate casting device used to cool and solidify molten metal by passing the molten metal through two casting rollers.

Background Art

A thin plate casting device for passing molten non-ferrous metal through two rotating casting rollers to cool and solidify the molten metal is used to form a thin plate of a non-ferrous metal such as magnesium. When the thin plate casting device is used, the molten metal spreading between the casting rollers is cooled and solidified by the casting rollers, and a thin plate is formed. Since a manufacturing condition or a manufacturing process affects thickness uniformity of the thin plate manufactured by the thin plate casting device, methods for manufacturing the thin plate with high reliability are being actively studied.

Disclosure

The present invention has been made in an effort to provide a thin plate casting device for controlling a width of an oxide layer formed on edge part surfaces of a casting roller and eliminating defects of a surface of a thin plate.

In addition, the present invention has been made in an effort to provide a thin plate casting device for preventing leakage of a molten metal toward the outside of a casting roller. Further, the present invention has been made in an effort to provide a thin plate casting device for controlling a flow of a molten metal in a nozzle assembly to obtain an optimized thickness of a thin plate.

According to an exemplary embodiment of the present invention, a thin plate casting device includes a pair of casting rollers facing each other, a nozzle assembly, at least one brush assembly, and a driver. The nozzle assembly is positioned at an inflow area formed between the pair of casting rollers to supply a molten metal. The at least one brush assembly includes a rotational shaft that is capable of moving and a brush fixed to the rotational shaft. In addition, the brush assembly is positioned at a location corresponding to the casting rollers. The thin plate casting device may further include an oxide layer thickness measuring unit and a controlling unit. The oxide layer thickness measuring unit measures a thickness of an oxide layer formed on a surface of the casting roller. The controlling unit receives a signal from the oxide layer thickness measuring unit and selectively drives the driving unit and the cylinder according to the signal. The oxide layer thickness measuring unit may include a sensor corresponding to edge part surfaces of the casting roller, and an oxide layer thickness calculating unit for receiving a signal from the sensor, calculating the thickness of the oxide layer formed on the surface of the casting roller, and transmitting the calculated thickness to the controlling unit. The pair of casting rollers may include a first casting roller and a second casting roller. The at least one brush assembly may include a plurality of brush assemblies, wherein the brush assemblies include a first brush assembly corresponding to the first casting roller and a second brush assembly corresponding to the second casting roller. The driver may include first and second driving units respectively connected to rotational shafts of the first and second brush assemblies to rotate the rotational shafts, and first and second cylinders for moving the first and second brush assemblies toward surfaces of the first and second casting rollers. The thin plate casting device may further include a thin plate defect measuring unit that is positioned on a moving path of a thin plate output from the casting rollers to measure defects on a surface of the thin plate, and transmits a signal regarding the defects to the controlling unit. The thin plate defect measuring unit may be a visual sensor. According to an exemplary embodiment of the present invention, a thin plate casting device includes first and second casting rollers facing each other, a nozzle assembly, and a cooling gas spraying device. The nozzle assembly is positioned at an inflow area formed between the first and second casting rollers to supply a molten metal. The cooling gas spraying device supplies a cooling gas to the molten metal. The cooling gas spraying device may be positioned at both sides of an output area of the casting roller to spray the cooling gas to both edge parts of the output thin plate. The thin plate casting device may further include a thin plate defect measuring unit and a controlling unit. The thin plate defect measuring unit is positioned on a moving path of the thin plate output from the first and second casting rollers to measure defects on a surface of the thin plate. The controlling unit is connected to the thin plate defect measuring unit and the cooling gas spraying device to control an operation of the cooling gas spraying device according to a signal transmitted from the thin plate defect measuring unit. According to an exemplary embodiment of the present invention, a thin plate casting device includes first and second casting rollers facing each other, and a nozzle assembly. The nozzle assembly is positioned at an inflow area formed between the tirst and second casting rollers to supply a molten metal. The nozzle assembly includes upper and lower members positioned to face each other to form a space therebetween, and at least one controlling dam disposed in the space to control a flow of the molten metal. The controlling dam may include a stirring member, an axis, and a knob. The stirring member is positioned in the space. The axis has an end fixed to the stirring member and another end exposed to an outside of the nozzle assembly. The knob is fixed to the other end to rotate the stirring member. Both ends of the stirring member may be sharp. A thickness of the stirring member may be gradually increased from both ends to a center part of the stirring member.

Since the thin plate casting device according to the exemplary embodiment of the present invention performs a rolling process to edge parts of the casting roller and eliminates an oxide layer functioning as a thermal transferring preventing layer or reduces a thickness of the oxide layer, a solidification shell may be uniformly formed at edge parts of the casting roller. Therefore, a thin plate having a good quality of edge parts may be manufactured.

In addition, since the thin plate casting device according to the exemplary embodiment of the present invention sprays the cooling gas to the thin plate output from the casting roller when damage occurs in an edge dam, the molten metal is forcibly cooled to prevent leakage of the molten metal to the outside, and a thin plate having a width that is greater than a predetermined width may be prevented.

Further, since the thin plate casting device according to the exemplary embodiment of the present invention includes a controlling dam for controlling a flow of the molten metal in the nozzle assembly, an optimum thickness of the thin plate may be obtained. Therefore, the thickness of a final product after the rolling process may be uniformly formed.

Description of Drawings

FIG. 1 is a perspective view of a thin plate casting device according to an exemplary embodiment of the present invention.

FIG. 2 is a block diagram representing a controlling system of the thin plate casting device according to the exemplary embodiment of the present invention.

FIG. 3 is a perspective view of the thin plate casting device according to another exemplary embodiment of the present invention. FIG. 4 is a block diagram representing a controlling system of the thin plate casting device according to the exemplary embodiment of the present invention. FIG. 5 is a perspective view of the thin plate casting device according to the exemplary embodiment of the present invention.

FIG. 6 is a top plan view of a configuration of a nozzle assembly of the thin plate casting device shown in FIG. 5. FIG. 7 is a longitudinal cross-sectional view of the nozzle assembly of the thin plate casting device shown in FIG. 5.

FIG. 8 is a cross-sectional view representing an optimum thickness of the thin plate.

FIG. 9 is a diagram representing a stirring member disposed in the nozzle assembly when a molten metal is excessively provided to both edge parts of the nozzle assembly.

Best Mode

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. It is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. In the figures, dimensions of constituent elements are magnified to clarify the present invention. When the constituent elements are referred to as a "first" element and a "second" element, the words "first" and "second" are not used to limit the constituent elements but are only used to classify the constituent elements. Therefore, the "first" and "second" constituent elements may be selectively used. FIG. 1 is a perspective view of a thin plate casting device according to an exemplary embodiment of the present invention. The thin plate casting device according to the exemplary embodiment of the present invention includes an upper casting roller 111 and a lower casting roller 112 that rotate in opposite directions, and a nozzle assembly 113 positioned at an inflow area of the upper casting roller 111 and the lower casting roller 112 to provide a molten metal. The upper casting roller 111 and the lower casting roller 112 are disposed to have a predetermined gap therebetween.

The molten metal provided in the nozzle assembly 113 is output from the nozzle assembly 113 to pass between the upper casting roller 111 and the lower casting roller 112. The molten metal output from the nozzle assembly 113 is cooled and solidified while passing between the upper casting roller 111 and the lower casting roller 112, and it is formed in a thin plate shape to be output from the upper casting roller 111 and the lower casting roller 112.

FIG. 2 is a block diagram representing a controlling system of the thin plate casting device according to the exemplary embodiment of the present invention. The thin plate casting device according to the exemplary embodiment of the present invention includes an oxide layer thickness measuring unit 120 for measuring the thickness of an oxide layer formed on surfaces of the upper and lower casting rollers 111 and 112, a thin plate defect measuring unit 140 for measuring defects of a thin plate S, a controlling unit 130 for receiving a signal from the oxide layer thickness measuring unit 120 and the thin plate defect measuring unit 140, and a driver 160 for driving a brush assembly 150 according to a controlling operation of the brush assembly 150 and the controlling unit 130.

The oxide layer thickness measuring unit 120 includes a first sensor 121 neighboring the upper casting roller 111, a second sensor 122 neighboring the lower casting roller 112, and oxide layer thickness calculating units 123 and 124 respectively connected to the first and second sensors 121 and 122.

The first sensor 121 and the second sensor 122 correspond to edge parts of the upper casting roller 111 and the lower casting roller 112, and generate signals for oxide layers formed on surfaces of the edge parts of the upper and lower casting rollers 111 and 112.

The signals generated from the first sensor 121 and the second sensor 122 are respectively transmitted to the oxide layer thickness calculating units 123 and 124, and the oxide layer thickness calculating units 123 and 124 use the transmitted signals to calculate thicknesses of the oxide layers formed on the surfaces of the edge parts of the upper and lower casting rollers 111 and 112.

The thin plate defect measuring unit 140 is positioned at a location corresponding to the thin plate S output from the upper casting roller 111 and the lower casting roller 112, (i.e., positioned on a thin plate S moving path) to measure defects that may exist on a surface of the thin plate S. For example, the thin plate defect measuring unit 140 may be a visual sensor.

The oxide layer thickness calculating units 123 and 124 of the oxide layer thickness measuring unit 120 and the controlling unit 130 connected to the thin plate defect measuring unit 140 control an operation of the brush assembly 150 according to information on the oxide layer thickness and the thin plate defect from the oxide layer thickness calculating units 123 and 124 and the thin plate defect measuring unit 140. That is, when an oxide layer of a tnicKness mat is greater tnan a predetermined level is formed on the surfaces of the edge parts of the upper casting roller 111 or the lower casting roller 112, the controlling unit 130 drives the brush assembly 150 to reduce the thickness of the oxide layer formed on the surface of the upper and lower casting roller 111 or 112 to be less than the predetermined level.

When the controlling unit 130 determines that the oxide layers formed on the edge part surfaces of the upper and lower casting rollers 111 and 112 in the above process are less than the predetermined thickness, the controlling unit 130 stops the operation of the brush assembly 150. When the controlling unit 130 uses the signals transmitted from the thin plate defect measuring unit 140 and determines that there is a defect on the surface of the thin plate, the controlling unit 130 drives the brush assembly 150 to reduce the thickness of the oxide layers of the surfaces of the upper and lower casting rollers 111 and 112 to be lower than the predetermined thickness. In addition, when the thickness of the oxide layers formed on the edge part surfaces of the upper casting roller 111 and the lower casting roller 112 is reduced to be lower than the predetermined thickness by the brush assembly 150 and the thin plate defect measuring unit 140 measures no defects of the thin plate surface, the controlling unit 130 stops the operation of the brush assembly 150. A configuration of the brush assembly 150 will now be described with reference to FIG. 1.

The brush assembly 150 includes first and second brush assemblies 151 and 152.

The first and second brush assemblies 151 and 152 are positioned to neighbor the upper casting roller 111 and the lower casting roller 112, and are capable of moving toward the upper casting roller 111 and the lower casting roller 112.

The first and second brush assemblies 151 and 152 respectively operate to correspond to the upper and lower casting rollers 111 and 112, and for convenience of description, the first brush assembly 151 will be exemplified and described.

The first brush assembly 151 includes a rotational shaft 151a that is capable of moving toward the upper casting roller 111, and at least one of brushes 151b and 151c fixed on the rotational shaft 151a. According to rotation of the brush assembly 151 (i.e., rotation of the brushes 151b and 151c), the surface of the upper casting roller 111 is ground by the brushes 151b and 151c. In FIG. 1, one brush 152b is illustrated among brushes forming the second brush assembly 152. However, according to the exemplary embodiment ot the present invention, wnen the brushes correspond to both edge parts of the casting roller to grind the edge part surfaces, the number of brushes is not limited.

The driver 160 for rotating the first and second brush assemblies 151 and 152 (i.e., rotating the rotational shaft 151a) includes first and second driving units 161a and 161b (see FIG. 2) respectively connected to the rotational shaft 151a of the first and second brush assemblies 151 and 152 to rotate the rotational shaft 151a, and first and second cylinders 162a and 162b for moving the first and second brush assemblies 151 and 152 toward the upper casting roller 111 and the lower casting roller 112.

The first and second driving units 161a and 161b and the first and second cylinders 162a and 162b are electrically connected to the controlling unit 130, and therefore the controlling unit 130 controls operations of the first and second driving units 161a and 161b and the first and second cylinders 162a and 162b. Operations and functions of the thin plate casting device according to the exemplary embodiment of the present invention will now be described with reference to the figures.

The molten metal output from the nozzle assembly 113 flows between the upper casting roller 111 and the lower casting roller 112. The molten metal is cooled and solidified while passing between the upper casting roller 111 and the lower casting roller 112, and it is formed in a thin plate shape to be output from the upper casting roller 111 and the lower casting roller 112.

In the above process, the first sensor 121 and the second sensor 122 respectively neighboring the upper casting roller 111 and the lower casting roller 112 transmit signals including information on the surfaces of the upper casting roller 111 and the lower casting roller 112 (particularly, information on an oxide layer formed on the edge part) to the oxide layer thickness calculating units 123 and 124.

The oxide layer thickness calculating units 123 and 124 calculate the thickness of the oxide layers formed on the edge parts of the upper and lower casting rollers 111 and 112 based on the signals generated from the first sensor 121 and the second sensor 122, and transmit the calculated thickness to the controlling unit 130. When the thickness of the oxide layers of the edge part surfaces of the upper casting roller 111 and lower casting roller 112 that are transmitted from the oxide layer thickness calculating units 123 and 1240 is greater than an established value, the controlling unit 130 drives the first and second driving units 161a and 161b and the first and second cylinders 162a ana IbZD connected to tne rotational shaft 151a of the first and second brush assemblies 151 and 152.

Therefore, because the upper casting roller 111 and the lower casting roller 112 rotate when the brushes 151b and 151c of the first and second brush assemblies 151 and 152 contact the edge part surfaces of the upper casting roller 111 and the lower casting roller 112, the oxide layers formed on the edge part surfaces of the upper casting roller 111 and the lower casting roller 112 may be eliminated or the thickness thereof may be reduced.

When the thickness of the oxide layers formed on the edge part surfaces of the upper casting roller 111 and the lower casting roller 112 is reduced to be lower than the established value, the controlling unit 130 stops operations of the first and second driving units 161a and 161b and the first and second cylinders 162a and 162b to separate the first and second brush assemblies 151 and 152 from the upper casting roller 111 and the lower casting roller 112 and stop the rotation of the brushes 151b and 151c.

The thin plate defect measuring unit 140 provided on the moving path of the thin plate S transferring through the upper casting roller 111 and the lower casting roller 112 measures defects on the surface of the thin plate S (i.e., defects formed by oxide layers that are excessively formed on the edge parts of the upper and lower casting rollers 111 and 112) to transmit a signal of the measured defects to the controlling unit 130.

The controlling unit 130 determines based on the signal transmitted from the thin plate defect measuring unit 140 whether there is a defect on the thin plate, and when determining that there is a defect, the controlling unit 130 drives the first and second driving units 161a and 161b and the first and second cylinders 162a and 162b to reduce the thickness of the oxide layers of the edge part surfaces of the upper and lower casting rollers 111 and 112 to be lower than the predetermined thickness.

Therefore, the thickness of a heat transferring prevention layer that prevents heat of the molten metal from being transferred to the upper and lower casting rollers 111 and 112 (i.e., the oxide layer formed on the edge part surfaces of the upper casting roller 111 and the lower casting roller 112) may be reduced.

Accordingly, since the heat of the molten metal is efficiently transmitted to the upper and lower casting rollers 111 and 112 (particularly, transmitted to the respective edge parts in which solidification is delayed), a solidification shell of the molten metal is uniformly formed at the edge parts of the upper and lower casting rollers 111 and 112, and therefore no defects occur in the edge parts ot tne tfiin plate.

FIG. 3 is a perspective view of the thin plate casting device according to another exemplary embodiment of the present invention. Referring to FIG. 3, the thin plate casting device includes an upper casting roller 211, a lower casting roller 212, and a nozzle assembly 213. Since the thin plate casting device shown in FIG. 3 is similar to the thin plate casting device shown in FIG. 1 and FIG. 2, like reference numerals designate like elements, and detailed descriptions thereof will be omitted.

An edge dam (not shown) including a refractory is formed at both sides of the nozzle assembly 213 to prevent leakage of the molten metal to the outside. In addition, cooling gas spraying devices 221 and 222 for spraying a cooling gas are provided on both sides of an output area of the upper casting roller 211 and the lower casting roller 212. The cooling gas is externally provided to the cooling gas spraying devices 221 and 222, and is electrically connected to a controlling unit that will be described later. Therefore, the cooling gas spraying devices 221 and 222 spray the cooling gas to both edge parts of the thin plates S output from the upper casting roller 211 and the lower casting roller 212 according to a control signal of the controlling unit.

FIG. 4 is a block diagram representing a controlling system of the thin plate casting device according to the current exemplary embodiment of the present invention. The thin plate casting device according to the exemplary embodiment of the present invention includes the cooling gas spraying devices 221 and 222 provided to both sides of the output area of the upper and lower casting rollers 211 and 212, a controlling unit 223 for controlling the cooling gas spraying devices 221 and 222, and a thin plate defect measuring unit 224 positioned on a moving path of the thin plate S to measure defects on the edge part of the thin plate.

The cooling gas spraying devices 221 and 222 respectively correspond to both edge parts of the thin plate S output from the upper and lower casting rollers 211 and 212, and externally receive the cooling gas.

A fluid controlling means such as a valve provided in the cooling gas spraying devices 221 and 222 operates according to a control signal of the controlling unit 223, and therefore a spraying amount and a spraying time of the cooling gas output from the cooling gas spraying devices 221 and 222 may be controlled. For example, the cooling gas may be nitrogen or argon.

The thin plate defect measuring unit 224 is positioned at a location corresponding to the thin plate S output from the upper casting roller 211 and the lower casting roller 212 (i.e., at a moving path of the thin plate S) to measure defects that may exist on the surface of the thin plate b (i.e., both edge parts), tor example, the thin plate defect measuring unit 224 may be a visual sensor.

The controlling unit 223 electrically connected to the thin plate defect measuring unit 224 is electrically connected to the cooling gas spraying devices 221 and 222 to control operations of the cooling gas spraying devices 221 and 222.

Operations and functions of the thin plate casting device according to the exemplary embodiment of the present invention will now be described with reference to the figures.

The molten metal output from the nozzle assembly 213 is supplied between the upper casting roller 211 and the lower casting roller 212, and it is cooled and solidified by the upper casting roller 211 and the lower casting roller 212 to be formed in a thin plate shape.

The thin plate defect measuring unit 224 positioned on the moving path of the thin plate S transferring through the upper casting roller 211 and the lower casting roller 212 measures defects that may exist on the surface of the thin plate S (i.e., defects caused by the edge part of the thin plate protruding toward the outside by a predetermined width because the molten metal is leaked to the outside by damage of the edge dam), and transmits the measured defect to the controlling unit 223. The controlling unit 223 determines based on the signal transmitted from the thin plate defect measuring unit 224 whether a defect is generated on the thin plate, and when determining the defect, the controlling unit 223 drives the cooling gas spraying devices 221 and 222.

Therefore, the cooling gas is sprayed to both edge parts of the thin plate that is output from the upper and lower casting rollers 211 and 212 and is not yet completely cooled and solidified, and therefore both edge parts of the thin plate are quickly cooled at a rate that is faster than natural cooling.

As described, since the molten metal that is spreading and leaking to the outside through damage to the edge dam is quickly cooled by the sprayed cooling gas, an increase of the width of the thin plate to be greater than a predetermined width since the edge parts of the thin plate is protruded to the outside may be prevented.

As an example, the controlling unit 223 controls the controlling means in the cooling gas spraying devices 221 and 222 according to a defect level of both edge parts of the thin plate (i.e., a level of protrusion in the width of the thin plate) to control the cooling gas spraying amount. For example, an open/ close rate of the valve is controlled to control the cooling gas spraying amount.

FIG. 5 is a perspective view of the thin plate casting device according to the exemplary embodiment of the present invention. FIG. 6 is a top plan view of a configuration of the nozzle assembly of the thin plate casting device shown in FIG. 5. FIG. 7 is a longitudinal cross-sectional view of the nozzle assembly of the thin plate casting device shown in FIG. 5. In further detail, FIG. 6 is a longitudinal cross- sectional view representing the stirring member disposed in the nozzle assembly when the molten metal is excessively provided to a center part of the nozzle assembly. Referring to FIG. 5, the thin plate casting device according to the exemplary embodiment of the present invention includes upper and lower casting rollers 311 and 312 rotating in opposite directions, and a nozzle assembly 313 provided at an inflow area of the upper casting roller 311 and the lower casting roller 312 to provide the molten metal. The molten metal provided in the nozzle assembly 313 is sprayed from the nozzle assembly 313 to pass between the upper casting roller 311 and the lower casting roller 312. The molten metal output from the nozzle assembly 313 is cooled and solidified while transferring between the upper casting roller 311 and the lower casting roller 312, and it is formed as a thin plate shape S of a predetermined width to be output from the upper casting roller 311 and the lower casting roller 312.

Referring to FIG. 6, an edge dam 314 including a refractory is formed at both sides of the nozzle assembly 313 to prevent leakage of the molten metal to the outside.

The nozzle assembly 313 includes an upper member 313a and a lower member 313b. A space 313c that is a flowing path of the molten metal is formed in the nozzle assembly 313 by the upper member 313a and the lower member 313b. At least one controlling dam 320 is disposed in the space 313c of the nozzle assembly 313. The controlling dam 320 controls the flow of the molten metal.

Referring to FIG. 7, the controlling dam 320 includes a stirring member 321 positioned in the space 313c of the nozzle assembly 313, an axis 322 fixed to the stirring member 321, and a knob 323 fixed to an upper part of the axis 322.

The axis of the controlling dam 320 penetrates through the upper member 313a or the lower member 313b so that an end of the axis is exposed to the outside, and the knob 323 for rotating the stirring member 321 is fixed to the exposed end. Therefore, when a user rotates the knob 323 of the nozzle assembly 313, the stirring member 321 is rotated in the space 313c of the nozzle assembly 313. In FIG. 7, while it is illustrated that the knob όl' ό ot the controlling dam όzu is positioned on the upper member 313a of the nozzle assembly 313, the knob 323 may be positioned on the lower member 313b. However, when the knob 323 is positioned on the upper member 313a of the nozzle assembly 313, the user may easily operate the knob 323.

An operation and a function of the thin plate casting device according to the exemplary embodiment of the present invention will now be described with reference to the figures.

The molten metal output from the nozzle assembly 313 flows between the upper casting roller 311 and the lower casting roller 312. It is cooled and solidified while transferring between the upper casting roller 311 and the lower casting roller 312, and it is formed as a thin plate shape with a predetermined width.

However, as described above, the thickness of the thin plate S depends on a thermal transformation of the upper and lower casting rollers 311 and 312 and a roller gap caused by mechanical transformation. FIG. 8 is a cross-sectional view representing an optimum thickness of the thin plate. Referring to FIG. 8, since the thin plate S is transformed in a width direction in a rolling process, a shape of the thin plate S output from the upper and lower casting rollers 312 is formed such that a thickness Tc of a center part of the thin plate is thicker than a thickness of the both edge parts by a predetermined value.

When a difference between the thickness Tc and the thickness Te is not within the predetermined value by the thermal transformation of the upper and lower casting rollers 311 and 312 and the mechanical transformation of the roller gap, the user controls the controlling dam 320 to control a flowing direction of the molten metal in the nozzle assembly 313.

FIG. 6 is a diagram representing the stirring member disposed in the nozzle assembly when the molten metal is excessively provided to a center part of the nozzle assembly. Referring to FIG. 6, the thickness Tc of the center part of the thin plate is thicker than the thickness Te of both edge parts when the molten metal excessively flows in a center part of the space 313c in the nozzle assembly 313. Therefore, the user rotates the stirring member 321 by using the knobs 323 of the respective controlling dams 320 so that more molten metal flows to both edge parts of the space 313c of the nozzle assembly 313.

The greater the amount of molten metal flowing to both edge parts of the space 313c of the nozzle assembly 313 according to a disposition state of the controlling dam 320 (i.e., a disposition state of the stirring member 321), the more the thickness of the edge parts of the thin plate output trom tne upper ana lower casting rollers 311 and 312 increases, and therefore an optimum thickness shown in FIG. 8 may be obtained.

FIG. 9 is a diagram representing the stirring member disposed in the nozzle assembly when the molten metal is excessively provided to both edge parts of the nozzle assembly. Referring to FIG. 9, the thickness Tc is thicker than the thickness Te by a value that is lower than the predetermined value or the thickness Tc is the same as the thickness Te when the molten metal excessively flows at both edge parts of the space 313c of the nozzle assembly 313. In this case, the user rotates the stirring member 321 by using the knob 323 of each controlling dam 320 to partially interrupt a flow of the molten metal flowing to both edge parts, and therefore more molten metal flows to the center part of the space 313c of the nozzle assembly 313.

More molten metal flows to the center part of the space 313c of the nozzle assembly 313 according to the disposition state of the controlling dam 320 shown in FIG. 9, and therefore the center part of the thin plate S output from the upper and lower casting rollers 311 and 312 has the optimum thickness shown in FIG. 8.

For example, the stirring member 321 of the controlling dam 320 may be formed in a streamlined shape to efficiently flow the molten metal. That is, as shown in FIG. 9, the thickness of both ends of the stirring member 321 is sharp and the thickness is gradually increased toward a center part of the stirring member 321 to be thicker.

Claims

WHAT IS CALIMED IS

1. A thin plate casting device comprising: a pair of casting rollers facing each other; a nozzle assembly positioned at an inflow area formed between the pair of casting rollers to supply a molten metal; at least one brush assembly comprising a rotational shaft that is capable of moving and a brush fixed to the rotational shaft, the brush assembly positioned in a location corresponding to a casting roller; and a driver comprising a driving unit for rotating the rotational shaft of the brush assembly and a cylinder for moving the brush assembly toward the casting roller.

2. The thin plate casting device of claim 1, further comprising: an oxide layer thickness measuring unit for measuring a thickness of an oxide layer formed on a surface of the casting roller; and a controlling unit for receiving a signal from the oxide layer thickness measuring unit and selectively driving the driving unit and the cylinder according to the signal.

3. The thin plate casting device of claim 2, wherein the oxide layer thickness measuring unit comprises a sensor corresponding to edge part surfaces of the casting roller, and an oxide layer thickness calculating unit for receiving a signal from the sensor, calculating the thickness of the oxide layer formed on the surface of the casting roller, and transmitting the calculated thickness to the controlling unit.

4. The thin plate casting device of claim 1, wherein the pair of casting rollers includes a first casting roller and a second casting roller, the at least one brush assembly includes a plurality of brush assemblies, the brush assemblies including a first brush assembly corresponding to the first casting roller and a second brush assembly corresponding to the second casting roller, and the driver includes first and second driving units respectively connected to rotational shafts of the first and second brush assemblies to rotate the rotational shafts and first and second cylinders for moving the first and second brush assemblies toward surfaces of the first and second casting rollers.

5. The thin plate casting device of claim 2, further comprising a tfun plate defect measuring unit that is positioned on a moving path of a thin plate output from the casting rollers to measure defects on a surface of the thin plate, and that transmits a signal regarding the defect to the controlling unit.

6. The thin plate casting device of claim 5, wherein the thin plate defect measuring unit is a visual sensor.

7. A thin plate casting device comprising: first and second casting rollers facing each other; a nozzle assembly positioned at an inflow area formed between the first and second casting rollers to supply a molten metal; and a cooling gas spraying device for supplying a cooling gas to the molten metal.

8. The thin plate casting device of claim 7, wherein the cooling gas spraying device is positioned at both sides of an output area of the casting roller to spray the cooling gas to both edge parts of the output thin plate.

9. The thin plate casting device of claim 7, further comprising: a thin plate defect measuring unit positioned on a moving path of the thin plate output from the first and second casting rollers to measure defects on a surface of the thin plate; and a controlling unit connected to the thin plate defect measuring unit and the cooling gas spraying device to control an operation of the cooling gas spraying device according to a signal transmitted from the thin plate defect measuring unit.

10. A thin plate casting device comprising: first and second casting rollers facing each other; and a nozzle assembly positioned at an inflow area formed between the first and second casting rollers to supply a molten metal, wherein the nozzle assembly includes upper and lower members positioned to face each other to form a space therebetween, and at least one controlling dam disposed in the space to control a flow of the molten metal.

11. The thin plate casting device of claim 10, wherein the controlling dam comprises: a stirring member positioned in the space; an axis having an end fixed to the stirring member and another end exposed to the outside of the nozzle assembly; and a knob fixed to the other end to rotate the stirring member.

12. The thin plate casting device of claim 10, wherein both ends of the stirring member are sharp.

13. The thin plate casting device of claim 13, wherein a thickness of the stirring member is gradually increased from the both ends to a center part of the stirring member.