JP2018538448A - Plating apparatus and plating method - Google Patents

Abstract

In order to improve productivity and product quality while simplifying the process, a plating bath for hot-plating the steel plate, which is disposed on one or both sides of the steel plate at the rear end of the plating bath along the steel plate traveling direction. A wiping unit that controls the amount of plating adhesion, and a cooling unit that is disposed on one or both sides of the steel plate at the rear end of the wiping unit along the steel plate traveling direction, and that cools the steel plate, There is provided a plating apparatus including a knife that contacts a plating layer to control the amount of plating deposited, and a coolant supply unit that supplies the knife with a cryogenic liquid containing liquid nitrogen or liquid helium to cool the knife.

Description

  The present invention relates to a plating apparatus and a plating method for continuously plating a molten metal on a steel plate surface.

  A wide variety of techniques for imparting corrosion resistance by plating a zinc-based metal or metal alloy on the surface of a steel sheet has been widely used. Plated steel sheets are being used in a wide range of applications, including general building materials, home appliances that require beautiful surface management, automobiles, shipbuilding, and other outer plate materials based on excellent corrosion resistance.

  A hot dip galvanizing facility (CGL; Continuous Galvanizing Line) is a facility for producing a plated steel sheet by adhering molten zinc to the surface of the steel sheet. In the hot dip galvanizing equipment, the steel sheet is immersed in a plating pot containing hot dip zinc while passing through a sink roll disposed in the plating pot.

  The hot-dip galvanized steel sheet passes through the sink roll and changes its direction so that it comes out to the upper part of the plating pot. The steel sheet drawn out from the galvanizing pot is manufactured as a plated steel sheet through a process of adjusting the plating adhesion amount on the steel sheet surface and then a process of cooling the plating layer.

  In recent years, various companies are mass producing plated steel sheets, and it is necessary to develop differentiated technologies that can improve plating quality while simplifying the plating process so that product competitiveness can be further enhanced. It has been.

  Provided are a plating apparatus and a plating method capable of improving productivity and product quality while simplifying a process.

  Provided are a plating apparatus and a plating method which can easily and precisely control the amount of plating adhesion.

  Provided are a plating apparatus and a plating method capable of simplifying a plating adhesion amount control process and minimizing the occurrence of plating defects that may occur during the plating adhesion amount control process.

  Provided are a plating apparatus and a plating method which can simplify a steel sheet cooling process and perform cooling more rapidly.

  Provided are a plating apparatus and a plating method that can improve plating quality by minimizing the plating adhesion amount and plating layer structure deviation of a plated steel plate.

  Provided are a plating apparatus and a plating method capable of producing plated steel sheets having various compositions.

Therefore, the plating apparatus of this embodiment is
A plating bath for hot-plating a steel plate, a wiping portion arranged on one or both surfaces of the steel plate at the rear end of the plating bath along the steel plate traveling direction, and a wiping portion for controlling the plating adhesion amount of the steel plate, and the wiping portion along the steel plate traveling direction A cooling unit disposed on one or both sides of the steel plate at the rear end for cooling the steel plate, the wiping unit being in contact with the plating layer on the surface of the steel plate to control the amount of plating, and a liquid in the knife A refrigerant supply unit that supplies a cryogenic liquid containing nitrogen or liquid helium to cool the knife may be included.

The plating apparatus of this embodiment is
A plating bath for hot-plating a steel plate, a wiping portion arranged on one or both surfaces of the steel plate at the rear end of the plating bath along the steel plate traveling direction, and a wiping portion for controlling the plating adhesion amount of the steel plate, and the wiping portion along the steel plate traveling direction A cooling unit disposed on one or both sides of the steel plate at the rear end to cool the steel plate, the cooling unit being in contact with the plating layer on the steel plate surface to cool the plating layer; In addition, the cooling body may include a coolant supply unit that supplies a cryogenic liquid containing liquid nitrogen or liquid helium to cool the cooling body.

The plating apparatus of this embodiment is
A plating bath for hot-plating a steel plate, a wiping portion arranged on one or both surfaces of the steel plate at the rear end of the plating bath along the steel plate traveling direction, and a wiping portion for controlling the plating adhesion amount of the steel plate, and the wiping portion along the steel plate traveling direction A cooling unit disposed on one or both sides of the steel plate at the rear end for cooling the steel plate, the wiping unit being in contact with the plating layer on the surface of the steel plate to control the amount of plating, and a liquid in the knife Including a refrigerant supply unit that supplies a cryogenic liquid containing nitrogen or liquid helium to cool the knife, the cooling unit being in close contact with the plating layer on the steel sheet surface to cool the plating layer, at least one cooling body; In addition, the cooling body may include a coolant supply unit that supplies a cryogenic liquid containing liquid nitrogen or liquid helium to cool the cooling body.

  The knife may include a body that extends in the width direction of the steel plate and in which a cryogenic liquid circulates, and a tip portion that is installed at the front end of the body and that controls the amount of plating adhered to the plating layer of the steel plate.

  In the knife, the tip part may be cooled to a temperature of -250 to 5 ° C.

  The knife extends in the width direction of the steel plate and is rotatably installed, and a rotating body in which a cryogenic liquid circulates inside, and is installed on the outer peripheral surface of the rotating body at intervals along the circumferential direction. There may be included a tip portion that contacts the plating layer and controls the amount of adhesion of the plating, and a rotation driving portion that is connected to the rotating body and rotates the rotating body to place the one-side tip portion toward the steel plate surface.

  The tip portion may be installed so as to be detachable from the body or the rotating body.

  The wiping unit is provided in the knife and detects a contact load of the tip part with respect to the steel plate, and controls the pressing force of the tip part against the steel plate by moving the knife with respect to the steel plate by a detection signal of the load sensor The control part to perform may be further included.

  The tip portion may have a structure arranged on the steel plate in parallel to the width direction.

  The tip portion may be arranged to be inclined with respect to the width direction of the steel plate.

  The tip portion may be formed by being bent and arranged in a V shape or an inverted V shape along the moving direction of the steel plate.

  The wiping part extends in the steel plate width direction at the rear end of the knife along the steel plate traveling direction, and a cryogenic liquid circulates in the inside thereof, and adheres to the plating layer on the steel plate surface to control the amount of plating, thereby removing the steel plate. It may further include a chill roll that is rapidly cooled.

  The wiping unit is provided in the chill roll to detect a contact load of the chill roll with respect to the steel plate, and a control for controlling the pressing force of the chill roll with respect to the steel plate by moving the chill roll with respect to the steel plate by a detection signal of the load sensor. A part may be further included.

  The wiping unit may further include a scraper that contacts the chill roll and removes contaminants attached to the chill roll surface.

  The cooling body includes a cooling roll that extends in the width direction of the steel sheet and in which a cryogenic liquid circulates and is pressurized to the plating layer on the surface of the steel sheet to apply cold air. It may be a structure arranged at intervals along the direction.

  The cooling body may further include a cooling belt that is wound and installed between at least two cooling rolls and applies cold air in close contact with the plating layer on the steel plate surface.

  The cooling belt may have a pattern transferred to the plating layer on the surface.

  The chill roll or cooling roll may be cooled to a temperature of -250 to 5 ° C.

  The chill roll or cooling roll may have an average surface roughness of 0.1 to 3 um.

  The cooling unit is provided in the cooling roll to detect a contact load of the cooling belt with respect to the steel plate, and a pressure applied to the cooling belt with respect to the steel plate by moving the cooling roll with respect to the steel plate by a detection signal of the load sensor It may further include a control unit for controlling.

  The structure may be such that the distance from the steel plate decreases as the knife moves from the knife to the cooling roll along the moving direction of the steel plate, and the thickness of the plating layer of the steel plate is gradually reduced.

  The plating method of the present embodiment includes a plating step for plating a steel plate, an adjustment step for adjusting the plating adhesion amount of the steel plate, and a cooling step for cooling the steel plate, wherein the adjustment step is performed with a knife that contacts the plating layer on the surface of the steel plate. The method may include a step of temporarily adjusting a plating deposition amount, and a step of cooling the knife by supplying a cryogenic liquid containing liquid nitrogen or liquid helium to the knife.

  The plating method of the present embodiment includes a plating step for plating a steel plate, an adjustment step for adjusting the plating adhesion amount of the steel plate, and a cooling step for cooling the steel plate, wherein the cooling step is a cooling body that contacts the plating layer on the surface of the steel plate. The method may include a step of cooling the steel plate by adding cold air to the steel plate, and a step of cooling the cooling body by supplying a cryogenic liquid containing liquid nitrogen or liquid helium to the cooling body.

  The plating method of the present embodiment includes a plating step for plating a steel plate, an adjustment step for adjusting the plating adhesion amount of the steel plate, and a cooling step for cooling the steel plate, wherein the adjustment step is performed with a knife that contacts the plating layer on the surface of the steel plate. The method includes a step of temporarily adjusting a plating adhesion amount and a step of cooling the knife by supplying a cryogenic liquid containing liquid nitrogen or liquid helium to the knife, and the cooling step contacts a plating layer on the surface of the steel sheet. The method may include a step of cooling the steel plate by adding cold air to the steel plate with a cooling body, and a step of cooling the cooling body by supplying a cryogenic liquid containing liquid nitrogen or liquid helium to the cooling body.

  The adjusting step includes the step of cooling the steel plate while secondarily adjusting the amount of plating adhesion with a chill roll that is in close contact with the plating layer on the surface of the steel plate, and supplying the chill roll with a cryogenic liquid containing liquid nitrogen or liquid helium. A cooling step may further be included.

  The adjusting step may further include a step of detecting a contact load of the knife or chill roll on the steel plate, and a step of controlling a pressing force of the knife or chill roll on the steel plate according to the detected contact load.

  The cooling step may further include a step of detecting a contact load of the cooling body with respect to the steel plate, and a step of controlling a pressing force of the cooling body with respect to the steel plate according to the detected contact load.

  The adjusting step and the cooling step may be configured to gradually reduce the thickness of the plating layer of the steel plate along the moving direction of the steel plate.

  In the adjusting step, the tip of the knife may be maintained at a temperature of −250 to 5 ° C.

  In the adjusting step, the chill roll may be maintained at a temperature of −250 to 5 ° C.

  In the cooling step, the cooling body may be maintained at a temperature of −250 to 5 ° C.

  The plated steel sheet may be rapidly cooled at a cooling rate of 20 ° C./sec or more.

  The plated steel sheet may be rapidly cooled to a temperature of 250 ° C. or lower at a cooling rate of 20 ° C./sec or higher.

  The method may further include a step of using the exhaust gas of liquid nitrogen used in the adjusting step or the cooling step as a reducing gas in the heat treatment furnace and an atmosphere maintaining gas in the cooling step.

  The cooling step may further include a step of transferring a pattern formed on the surface of the cooling body to the plating layer to form a pattern on the surface of the plating layer.

  As described above, according to the present embodiment, by simplifying the process and reducing the quality control elements, management can be facilitated and productivity can be improved. Therefore, it will be possible to increase product competitiveness and improve profitability compared to competitors.

  Moreover, by increasing the cooling efficiency and quenching the steel sheet more effectively, the length of the equipment for cooling can be reduced, and it is possible to produce a plated steel sheet with excellent surface quality by reducing the occurrence of steel sheet surface defects. It becomes like this.

  In addition, since the cooling gas does not come into contact with the steel sheet, it is possible to solve the problems of galvanized scattering, dross, and noise caused by conventional gas injection.

  Moreover, the effect of plating property improvement can be acquired also with respect to a hard-to-plate steel grade by performing rapid cooling using the chill roll which contacts a steel plate directly.

  In addition, precise control over the amount of plating is easy, and it becomes possible to manufacture a high-quality plated steel sheet by minimizing the deviation of the plating adhesion amount and plating layer structure deviation in the width direction of the steel sheet.

1 is a schematic drawing showing a hot dip galvanizing apparatus according to the present embodiment. It is the schematic drawing which showed the knife structure of the hot dip galvanizing apparatus by a present Example. It is the schematic drawing which showed the other Example with respect to the knife of the hot dip galvanizing apparatus by a present Example. 1 is a schematic diagram illustrating a contact load control structure for a steel plate of a knife according to an embodiment. 3 is a schematic diagram illustrating various embodiments of a knife tip structure and an arrangement structure with respect to a steel plate according to the present embodiment. 1 is a schematic drawing showing the structure of a chill roll of a hot dip galvanizing apparatus according to the present embodiment. It is the schematic which showed the cooling unit structure of the hot dip galvanizing apparatus by a present Example. It is the schematic which showed the cooling unit structure of the hot dip galvanizing apparatus by a present Example.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that a person having ordinary knowledge in the technical field to which the present invention can easily implement. In order that those having ordinary knowledge in the technical field to which the present invention belongs can be easily understood, the embodiments described below can be modified in various forms within the scope of the present invention without departing from the concept and scope of the present invention. However, the present invention is not limited to the embodiment.

  It is noted that the drawings are schematic and are not shown to fit the accumulation. The relative sizes and proportions of the parts in the drawings are shown enlarged or reduced in size for clarity and convenience in the drawings, and any size is merely exemplary. , Not limited.

  Hereinafter, the present embodiment will be described by taking as an example a hot dip galvanizing apparatus for plating a zinc-based metal or metal alloy on a steel sheet surface by a plating apparatus. This plating apparatus is not limited to the plating of zinc-based metals or metal alloys, and can be applied to all hot-dip plating apparatuses for various metals.

  FIG. 1 schematically shows a hot dip galvanizing apparatus according to this embodiment.

  As shown in FIG. 1, the plating apparatus of the present embodiment includes a plating bath 10 for hot-plating a steel plate P, and is disposed on one or both surfaces of the steel plate at the rear end of the plating bath 10 along the steel plate traveling direction. A wiping unit that controls the amount of plating on the steel plate, and a cooling unit that is disposed on one or both surfaces of the steel plate at the rear end of the wiping unit along the traveling direction of the steel plate to cool the steel plate.

  The steel plate P guided to the plating bath 10 is immersed in the molten metal while passing through a sink roll 12 disposed in the plating bath 10 and the hot dipping process proceeds. The traveling direction of the steel plate P is changed by the sink roll 12 and moves to the upper part of the plating bath 10. The steel plate P whose surface is plated with molten metal in the plating bath 10 is drawn out to the upper portion of the plating bath 10. The steel plate is manufactured as a plated steel plate through a wiping portion and a cooling portion that are sequentially arranged along the traveling direction. The steel sheet rapidly cooled through the cooling unit is advanced to the process through the tension roll 14.

  The plating solution applicable in this embodiment can be applied to all metals and alloy melts such as zinc and zinc alloys, aluminum and aluminum alloys, and any metal and alloy plating can be applied without any limitation. .

  In the present embodiment, the wiping portion has a structure in which the plating adhesion amount is adjusted by directly contacting the plating layer adhered to the steel plate surface.

  For this purpose, the wiping unit cools the knife 20 by contacting the plating layer on the surface of the steel plate P to control the amount of plating and supplying the knife 20 with a cryogenic liquid containing liquid nitrogen or liquid helium. The refrigerant supply unit 50 may be included.

  By directly contacting the knife 20 with the plating layer, it is possible to prevent contamination of the plating bath surface with oxides, and to more easily control the amount of plating on the steel plate. The coolant supply unit 50 cools the knife 20 with a cryogenic liquid so that the temperature of the knife 20 is lowered and the plating solution is fused to the knife 20 even when the knife 20 is in direct contact with the high-temperature plating layer. Can be prevented.

  In the present embodiment, the cooling part has a structure in which the steel sheet is cooled by directly contacting the plating layer on the steel sheet surface.

  For this purpose, the cooling unit supplies at least one cooling body 60 that adheres to the plating layer on the surface of the steel sheet to cool the plating layer, and supplies the cooling body 60 with a cryogenic liquid containing liquid nitrogen or liquid helium. The coolant supply unit 50 that cools the cooling body 60 may be included.

  The cooling body 60 is brought into direct contact with the plating layer to cool the plating layer of the steel sheet, so that the cooling capacity can be maximized and the steel sheet plating layer can be rapidly cooled. The cooling unit cools the cooling body 60 to a cryogenic liquid so that the temperature of the cooling body 60 is lowered and the plating solution is fused to the cooling body 60 even when the cooling body 60 is in direct contact with the high-temperature plating layer. Can be prevented.

  The refrigerant supply unit 50 is for supplying the cryogenic liquid to the knife 20 or the cooling body 60, and includes, for example, a tank in which the cryogenic liquid is accommodated, a supply line to which the cryogenic liquid is transferred, and a supply line. A supply pump installed above may be included. The refrigerant supply unit 50 can be applied to any structure that can supply a cryogenic liquid, and can be variously modified.

  Various liquids such as liquid argon may be used for the cryogenic liquid used in the refrigerant supply unit 50 in addition to liquid nitrogen and liquid helium. Economic efficiency can be improved compared with the case of using liquid nitrogen.

  In this way, the knife 20 and the cooling body 60 cooled by using the cryogenic liquid are in direct contact with the steel plate P to control the amount of plating of the steel plate and rapidly cool the plate. Can be precisely controlled, and the cooling rate of the plated steel sheet can be increased to 20 ° C./sec or more. Therefore, the length of the equipment line for cooling the steel sheet can be dramatically shortened, and the product production speed can be increased.

  The cryogenic liquid supplied to the knife 20 or the cooling body 60 through the refrigerant supply unit 50 may be gasified by heat exchange with the plating layer while passing through the knife 20 or the cooling body 60. The gas discharged from the knife 20 or the cooling body 60 is reused through a suitable filtration device as a reducing gas in a heat treatment furnace (furnace) in a steelmaking process or a gas for maintaining a non-oxidizing atmosphere in a cooling process. Can be done.

  FIG. 2 illustrates a specific structure of the knife according to the present embodiment.

  In this embodiment, the knife 20 is disposed opposite to both surfaces of the steel plate and adjusts the amount of plating solution applied to both surfaces of the steel plate P. The knives 20 arranged on both surfaces of the steel plate P have the same structure, and the following description will be made by taking only the knife for one surface of the steel plate as an example.

  As shown in FIG. 2, the knife 20 extends in the width direction of the steel sheet P, and a body 22 in which a cryogenic liquid circulates inside, and a tip that is installed at the front end of the body 22 and contacts a plating layer of the steel sheet. The structure which includes the part 24 and controls the plating adhesion amount on the steel plate surface may be used.

  The body 22 and the chip part 24 are made of metal such as stainless steel, ceramic, ceramic, or ceramic having excellent durability at a low temperature so that the body 22 and the chip part 24 can be stably used for a long time in a cryogenic environment using liquid nitrogen. You may manufacture with the metal material etc. which were coated.

  The body 22 is formed with a flow path 26 so that a cryogenic liquid passes therethrough. The refrigerant supply unit 50 connected to the body 22 circulates and supplies the cryogenic liquid through the flow path 26. The flow path 26 is formed to extend to the tip where the tip 24 is positioned so that the tip 24 installed at the tip of the body 22 can be sufficiently cooled, and the tip 24 is brought into contact with the cryogenic liquid. To get.

  In the present embodiment, the tip portion 24 may be detachably installed on the body 22.

  The tip portion 24 wears in contact with the high-temperature plating layer continuously. Therefore, it is possible to use the knife 20 continuously by replacing only the tip portion 24 from the body 22 during wear by making the wearable tip portion 24 into a replaceable component. The tip portion 24 may have a structure that is sharper toward the tip for more precise control of the amount of plating adhesion.

  The cryogenic liquid supplied to the body 22 cools the tip portion 24 while circulating along the flow path 26 so that the tip portion 24 can maintain a low temperature state. Therefore, the chip part 24 can primarily control the plating adhesion layer more accurately while preventing the plating solution from adhering to the chip part 24 in a state of being in contact with the plating layer.

  FIG. 3 illustrates another embodiment of the knife. The knife according to the embodiment of FIG. 3 has a structure including a plurality of tip portions so that the tip portion can be immediately replaced when it is abnormal.

  For this purpose, the knife 21 of the present embodiment is installed so as to be able to rotate and extend in the width direction of the steel sheet, and a rotating body 23 in which a cryogenic liquid circulates, and an outer peripheral surface of the rotating body 23 along the circumferential direction. The chip part 24 which is installed at an interval and contacts the plating layer on the surface of the steel sheet P to control the amount of plating adhesion, and the rotating body 23 is connected to the rotating body 23 to rotate the rotating body 23 so It may also include a rotational drive unit arranged toward the front.

  Therefore, when an abnormality such as wear of the tip portion 24 occurs, the rotating body 23 is rotated so that the tip portion 24 in use is separated from the steel plate, and the other tip portion 24 in standby is moved to the steel plate side, thereby instantly tipping. The part 24 can be replaced and used. As shown in FIG. 3, four tip portions 24 may be arranged at an angle of 90 degrees along the outer peripheral surface of the rotating body 23. Therefore, the rotating body 23 can be rotated at an angle of 90 degrees to move the tip portions 24 to the steel sheet surface side. The number of chip portions 24 can be variously modified.

  In this embodiment, the rotating body 23 may have a cylindrical shape. The rotating body 23 is not limited to a cylindrical shape, and may be a structure in which, for example, the body 22 described above is continuously arranged at an angle along the outer peripheral surface of the rotating shaft. Both ends of the rotating body 23 may be rotatably supported on a facility by a separate support base (not shown).

  The rotating body 23 can also be used stably for a long time in a cryogenic environment using liquid nitrogen, and is made of a metal such as stainless steel, ceramic, or a metal material coated with ceramic that has excellent cryogenic durability. May be manufactured.

  The rotating body 23 is formed with a flow path (not shown) so that a cryogenic liquid passes through the rotating body 23. The flow path formed inside the rotating body 23 may be connected to the refrigerant supply unit 50 through both ends of the rotating shaft of the rotating body 23. The cryogenic liquid supplied from the refrigerant supply unit 50 is circulated and supplied to the flow path inside the rotating body 23 through the tip of the rotating body 23. The flow path is extended from the surface on which the tip portion 24 is positioned so that the tip portion 24 installed on the outer peripheral surface of the rotating body 23 can be sufficiently cooled, so that the cryogenic liquid can contact the tip portion 24.

  A tip portion 24 is installed on the surface of the rotating body 23 along the axial direction. The tip portion 24 may be detachably installed on the surface of the rotating body 23.

  The rotation drive unit can be applied to any structure that rotates the rotating body 23 by a set angle. As shown in FIG. 3, for example, the rotation driving unit may include a step motor 27 that is connected by a rotating body 23 and a driving belt 25 to transmit power. Therefore, when the step motor 27 is rotationally driven by a certain amount, power is transmitted to the rotating body 23 through the driving belt 25, and the rotating body 23 rotates by the arrangement interval of the tip portions 24. Due to the rotation of the rotating body 23, the new tip portion 24 that is placed on the surface of the rotating body 23 and is waiting moves to the steel plate side and contacts the plating layer on the steel plate surface. Then, the tip 24, which is worn or abnormal due to the rotation of the rotating body 23, moves away from the steel plate surface to the standby position. The worn tip 24 is processed at the standby position through replacement or surface polishing operations.

  Thus, in the case of the present embodiment, the tip portion 24 can be easily replaced by rotating the rotating body 23 at a predetermined angle, so that the time required for replacing the tip portion 24 can be reduced and the work can proceed continuously. Become.

  In this embodiment, the knives 20 and 21 can cool the tip 24 to −250 to 5 ° C. by circulating a cryogenic liquid therein. When the temperature of the chip part 24 is higher than 5 ° C., there is a problem that a high-temperature plating solution adheres to the chip part 24. When the temperature of the chip part 24 is lower than −250 ° C., the problem of low-temperature brittle fracture of the chip part 24 occurs.

  The knives 20 and 21 are moved with respect to the steel plate to change the distance between the knives and the steel plate, thereby precisely adjusting the amount of plating deposited by the tip portion 24.

  When the knife 20 further approaches the plating layer of the steel plate or is separated from the plating layer to the outside, the distance between the tip portion 24 and the steel plate P is changed to adjust the plating adhesion amount of the steel plate.

  As shown in FIG. 4, for precise control of the amount of plating applied by the knife 20, the wiping unit is provided in the knife 20 and detects a contact load of the tip part 24 against the steel plate P. 30 and a control unit 32 that controls the pressing force of the tip portion 24 against the steel plate by moving the knife 20 relative to the steel plate according to the detection signal of the load sensor 30.

  The distance between the tip portion 24 and the steel plate P can be confirmed through the contact load of the tip portion detected through the load sensor 30. When the distance between the tip portion 24 and the steel plate P becomes narrower, the tip portion 24 penetrates deeply into the plating layer of the steel plate and the contact load increases while the amount of contact with the plating solution increases. If it is separated from the contact distance, the contact load with the plating solution decreases while the contact load decreases.

  The control unit 32 calculates the detection value of the load sensor 30 and moves the knife 20 with respect to the steel plate P in accordance with the plating adhesion amount set primarily, thereby controlling the plating adhesion amount.

  The movement of the knife 20 relative to the steel plate may be performed through a drive unit 34 such as a drive cylinder coupled to the knife 20, for example. A variety of power sources such as a drive cylinder and a motor may be used for the drive unit 34, and any structure that can linearly move the knife 20 with respect to the steel plate is applicable.

  Further, the control unit 32 can detect a change in the measured value of the load sensor 30 and check whether there is a device abnormality. At the time of device abnormality determination, necessary measures such as replacement of the tip portion 24 with the knife 20 can be taken immediately.

  FIG. 5 illustrates the form of the tip of the knife relative to the steel plate and the arrangement structure of the tip relative to the steel plate.

  In the present embodiment, the tip portion 24 installed on the knives 20 and 21 may be formed in various shapes such as a straight shape or a structure in which the middle portion is bent to form a V shape. The knife body 22 or the rotating body 23 on which the tip portion 24 is installed may have the same structure as the tip portion 24. For example, when the tip portion 24 has a V-shape, the body 22 of the knife 20 on which the tip portion 24 is installed may also have a V-shape in which the tip portion is shaped like the tip portion 24.

  As shown in FIG. 5, the tip portion 24 may be disposed on the steel plate P in parallel to the width direction. Moreover, the said chip | tip part 24 may be inclined and arrange | positioned with respect to the width direction of a steel plate.

  In addition, in the case where the tip portion 24 is bent in a V shape, the bent portion is in an inverted V shape or a V shape so that the bent portion faces in the moving direction of the steel plate or in the opposite direction in the moving direction of the steel plate. It may be arranged.

  In this way, by diversifying the arrangement of the chip part 24 in contact with the plating layer with respect to the steel plate P, when the plating layer comes into contact, the load of the plating solution applied to the chip part 24 is reduced and the plating layer is more smoothly attached. The amount can be adjusted.

  As shown in FIG. 1 and FIG. 6, the wiping part is disposed at the rear end of the knife 20 along the steel plate traveling direction to more precisely control the amount of plating on the steel plate, thereby forming the plating layer of the steel plate. A chill roll 40 for rapid cooling may be further included.

  The chill roll 40 is a roll structure that is disposed in the width direction of the steel sheet and is pressure-contacted to the plating layer. Both ends of the chill roll 40 may be rotatably supported on equipment by a separate support base (not shown). The chill roll 40 may have a freely rotatable structure and may rotate together with the movement of the steel plate or may be connected to a separate driving source and rotated at a set speed.

  In this embodiment, the chill roll 40 may have an average surface roughness of 0.1 to 3 um.

  If the surface roughness of the chill roll 40 is higher than 3 um, the problem of uneven post-processing due to inferior surface quality occurs. When the surface roughness of the chill roll 40 is lower than 0.1 μm, there arises a problem that post-treatment characteristics such as chemical conversion treatment are deteriorated.

  The chill roll 40 has a structure in which a cryogenic liquid circulates inside and is cooled to a low temperature. The chill roll 40 can be used stably for a long time in a cryogenic environment using liquid nitrogen. The chill roll 40 is made of a metal such as stainless steel, ceramic, or a metal material coated with a ceramic that has excellent cryogenic durability. May be manufactured.

  As shown in FIG. 6, a flow path is formed in the chill roll 40 so that the cryogenic liquid passes. The flow path formed inside the chill roll 40 may be connected to the refrigerant supply unit (see 50 in FIG. 1) through both ends of the rotating shaft of the chill roll 40. The cryogenic liquid supplied from the refrigerant supply unit 50 is circulated and supplied to the flow path inside the chill roll 40 through the tip of the chill roll 40. The surface of the chill roll 40 is maintained in a low-temperature cooling state by the cryogenic liquid supplied into the chill roll 40. Therefore, the chill roll 40 prevents the plating solution from adhering to the surface of the chill roll 40 in contact with the plating layer of the steel sheet P, and can rapidly cool the plating layer.

  The chill roll 40 pressurizes and adheres to the plating layer on the surface of the steel sheet P and secondarily precisely controls the plating adhesion amount of the steel sheet whose primary adhesion amount is controlled while passing through the knife 20. In addition, the chill roll 40 can rapidly cool the plating layer through direct heat exchange with the steel plate while being in pressure contact with the steel plate plating layer.

  In this embodiment, the chill roll 40 can be cooled to −250 to 5 ° C. by circulating a cryogenic liquid therein. When the temperature of the chill roll 40 is higher than 5 ° C., there arises a problem that the cooling performance and surface quality improvement efficiency of the plated steel sheet are lowered. When the temperature of the chill roll 40 is lower than −250 ° C., a problem of low temperature brittle fracture of the chill roll 40 occurs.

  As described above, the plating apparatus of the present embodiment can adjust the thickness of the plating layer by controlling the amount of plating more precisely through the low-temperature knife 20 and the chill roll 40 that are in contact with the plating solution on the surface of the steel sheet. In addition, the chill roll 40 cooled to a low temperature pressurizes and rapidly cools the plating layer, so that the structure of the plating layer can be refined and a small and uniform surface solidified structure can be obtained. The amount deviation and plating layer structure deviation are effectively reduced.

  By allowing the chill roll 40 to contact the plating layer and solidify the plating solution within a faster time, the plating apparatus can rapidly cool the steel sheet at a cooling rate of 20 ° C./sec. Further, since the chill roll 40 is cooled while pressurizing the plating layer under a predetermined pressure, it is possible to improve the plating performance even for a hard-to-platable steel type.

  In the case of the present embodiment, the sink roll 12 and the chill roll 40 of the plating bath 10 are in a state of supporting the steel plate P in conjunction with each other, and the steel plate is bent in the width direction in the process of passing through the contact knife 20. The phenomenon does not occur at all. That is, the steel plate passes through the sink roll 12 and the chill roll 40 at the front end and the rear end of the knife 20 along the steel plate moving direction, respectively. Therefore, the steel plate P passes through the knife 20 without occurrence of the current curving state in a state where the steel plate P is unrolled flat by the sink roll 12 and the chill roll 40.

  When a steel plate is bent, a plating adhesion amount deviation in the width direction occurs, and plating surface defects such as comb defects due to side surface overplating occur. In the case of the conventional structure, such plating surface defects due to the steel plate recursion phenomenon frequently occur, but in the case of this example, by preventing the occurrence of recursion of the steel plate, the amount of plating adhesion and the plating layer in the width direction are prevented. It is possible to produce a plated steel sheet with almost no structural deviation.

  The wiping unit of the present embodiment includes a load sensor 30 that is provided in the chill roll 40 and detects a contact load of the chill roll 40 with respect to a steel plate, as in the case of a knife, for precise control of the amount of plating applied by the chill roll 40, and the It may further include a control unit 32 that operates the drive unit 34 by the detection signal of the load sensor to move the chill roll 40 with respect to the steel plate to control the pressing force of the chill roll 40 on the steel plate.

  When the chill roll 40 approaches the plating layer of the steel plate P or is separated from the plating layer to the outside, the distance between the chill roll 40 and the steel plate is changed, and the plating adhesion amount of the steel plate and the thickness of the plating layer are precisely adjusted. Is done.

  Since the structure of the load sensor and the control unit for the chill roll 40 is the same as the structure of the load sensor 30, the control unit 32, and the driving unit 34 for the knife 20 described above, the same reference numerals are used, The description of the load sensor 30 and the control unit 32 for the knife 20 will be referred to and detailed description will be omitted below. Therefore, the control unit 32 calculates the detection value of the load sensor 30 and moves the chill roll 40 with respect to the steel sheet to pressurize the plating layer, thereby making it possible to more accurately determine the amount of plating adhesion and the thickness of the plating layer. Can be controlled. Further, the plating layer is pressurized by a chill roll and rapidly cooled at a cooling rate of 20 ° C./sec or more, so that a plating adhesion deviation in the width direction can be minimized and a plating layer with a finer structure can be obtained.

  In addition, the wiping portion has a structure for removing contaminants on the surface of the chill roll 40 in preparation for the case where the surface of the chill roll 40 is contaminated. For this purpose, as shown in FIG. 7, the wiping unit may further include a scraper 44 that contacts the chill roll 40 and removes contaminants attached to the surface of the chill roll 40. The scraper 44 may be installed so as to extend in the axial direction of the chill roll 40 and contact the surface of the chill roll 40. Therefore, the contaminants attached to the surface of the chill roll 40 while the chill roll 40 is rotated are applied to the scraper 44 and removed from the surface of the chill roll 40.

  Through the wiping section, the amount of plating is precisely adjusted, and rapid cooling is performed. The steel sheet is rapidly cooled to a set temperature or less while passing through a cooling part disposed at the rear end of the wiping part, and the thickness of the plating layer is precisely controlled.

  7 and 8 illustrate the structure of the cooling unit according to this embodiment.

  The cooling unit is provided with at least one cooling body 60 that cools the plating layer in close contact with the plating layer on the surface of the steel sheet, and supplies the cooling body 60 with a cryogenic liquid containing liquid nitrogen or liquid helium. A refrigerant supply unit 50 that cools 60 may be included.

  In the present embodiment, the cooling body 60 may include a cooling roll 62 that extends in the width direction of the steel plate and in which a cryogenic liquid circulates and is pressurized by the plating layer on the surface of the steel plate P to apply cold air. The cooling roll 62 may have a structure in which a plurality of cooling rolls 62 are arranged in multiple stages at intervals along the traveling direction of the steel sheet.

  The cooling roll 62 is a roll structure that is arranged in the width direction of the steel plate, like the chill roll 40. Both ends of the cooling roll 62 may be rotatably supported on a facility by a separate support base (not shown). The cooling roll 62 may be a freely rotatable structure that rotates together with the movement of the steel sheet, or may be connected to a separate drive source and rotated at a set speed.

  The cooling roll 62 has a structure in which a cryogenic liquid circulates inside and is cooled to a low temperature.

  Similar to the chill roll 40, a flow path 64 is formed in the cooling roll 62 so that a cryogenic liquid passes therethrough. The flow path 64 formed inside the cooling roll 62 may be connected to the refrigerant supply unit (see 50 in FIG. 1) through both ends of the rotating shaft of the cooling roll 62. The cryogenic liquid supplied from the refrigerant supply unit 50 is circulated and supplied to the flow path 64 inside the cooling roll 62 through the tip of the cooling roll 62. The surface of the cooling roll 62 maintains a low-temperature cooling state by the cryogenic liquid supplied into the cooling roll 62.

  The cooling body 60 may further include a cooling belt 66 that is wound and installed between at least two cooling rolls 62 and pressurizes and adheres to the plating layer on the surface of the steel sheet P to apply cool air. In the case of such a structure, not the cooling roll 62 but the cooling belt 66 comes into direct contact with the plated layer of the steel plate.

  The cooling roll 62 and the cooling belt 66 can be used stably for a long time in a cryogenic environment using liquid nitrogen, and are excellent in cryogenic durability such as metal, ceramic, or ceramic coating. You may manufacture with the metal material etc. which were made.

  In this embodiment, the cooling roll 62 or the cooling belt 66 in contact with the steel sheet surface may have an average surface roughness of 0.1 to 3 μm. When the surface roughness of the cooling roll 62 or the cooling belt 66 is higher than 3 μm, a problem of uneven post-processing due to inferior surface quality occurs, and when the surface roughness is lower than 0.1 μm, a chemical conversion treatment is performed. There arises a problem that the post-processing characteristics deteriorate.

  In this embodiment, a cooling belt 66 is wound around two cooling rolls 62 to form one cooling body 60, and one or a plurality of such cooling bodies 60 are arranged at intervals along the traveling direction of the steel sheet. It is made of a structured. The installation interval and the number of the cooling bodies 60 can be variously modified depending on the equipment and process conditions.

  Each cooling body 60 may have the same structure, and the structure for the one-side cooling body will be described below as an example.

  A cooling belt 66 is wound and installed between two separated cooling rolls 62, and the cooling belt 66 is in surface contact with the plating layer on the steel plate surface. For example, the cooling belt 66 can be rotated in accordance with the moving speed of the steel sheet by rotating the cooling roll 62 while being in contact with the steel sheet. By rotating the cooling belt 66 in accordance with the moving speed of the steel plate, friction between the steel plate and the cooling belt 66 can be minimized, and damage to the plating layer due to friction can be prevented.

  The cooling roll 62 cools the cooling belt 66 provided outside to a low temperature. Since the cooling belt 66 is in surface contact with the plating layer while being cooled to a low temperature by the cooling roll 62, the plating layer can be rapidly cooled. That is, the cooling belt 66 is in surface contact with the plating layer on the steel plate surface between the two cooling rolls 62. Therefore, the cooling area for the plated layer of the steel plate is increased by the contact area by the cooling belt 66. Therefore, the cooling unit of the present embodiment can increase the cooling area for the steel plate plating layer through the cooling belt 66 and increase the cooling rate.

  In the present embodiment, the cooling roll 62 can cool the temperature of the cooling belt 66 in contact with the plating layer to −250 to 5 ° C. by circulating a cryogenic liquid therein. When the temperature of the cooling belt 66 is higher than 5 ° C., there arises a problem that cooling performance and surface quality improvement efficiency of the plated steel sheet are lowered. When the temperature of the cooling belt 66 is lower than −250 ° C., the problem of low temperature brittle fracture of the cooling belt 66 occurs.

  In this way, the cooling belt 66 installed on the cooling roll 62 contacts the plating layer and rapidly solidifies the plating solution within a faster time, so that the plating apparatus of this embodiment allows the steel plate to be 20 ° C. / It becomes possible to rapidly cool to a temperature of 250 ° C. or lower at a cooling rate of sec.

  The cooling unit can tightly tighten the cooling belt 66 by adjusting the distance between the two cooling rolls 62 constituting the unit. When the cooling belt 66 is tensioned and unfolded tightly, the plating layer on the surface of the steel sheet and the cooling belt 66 are contacted and pressed uniformly, and the plating layer can be more uniformly pressurized and cooled.

  As shown in FIG. 8, for this purpose, the cooling unit may be provided with a drive cylinder 68 that extends and contracts between the two cooling rolls 62 around which the cooling belt 66 is wound. The drive cylinder 68 is driven by a signal from the control unit 32 so as to widen the space between the cooling rolls 62. When the space between the cooling rolls 62 is widened, the cooling belt 66 is unfolded tightly.

  The cooling roll 62 can precisely adjust the pressure applied to the plated layer of the steel plate. Therefore, although not shown, the cooling roll 62 may include a load sensor, a control unit, and a driving unit in the same manner as the chill roll 40. Since the structure for adjusting the pressure applied to the cooling roll is the same as the structure of the load sensor 30, the control unit 32, and the drive unit 34 for the chill roll 40 described above, a detailed description of the structure and operation thereof will be omitted. Therefore, the cooling roll presses the cooling belt against the steel plate with a set pressure to precisely control the thickness of the plated layer of the steel plate.

  That is, when the cooling roll 62 approaches the plating layer of the steel plate or is separated from the plating layer to the outside, the interval between the cooling belt 66 wound around the cooling roll 62 and the steel plate changes, and the plating layer of the steel plate is changed. The applied pressure is adjusted. As described above, the cooling unit calculates the detection value of the load sensor, moves the cooling roll 62 with respect to the steel plate, and precisely adjusts the plating layer pressurizing force by the cooling belt 66, thereby reducing the thickness of the plating layer. Can be controlled precisely.

  Here, the pressure applied to the cooling belt 66 by the movement of the cooling roll 62 may be the same or different for each of the plurality of cooling bodies 60 arranged along the moving direction of the steel plate. That is, each cooling body 60 arranged along the moving direction of the steel plate may be in close contact with the steel plate with the same applied pressure. Alternatively, each cooling body 60 may be brought into close contact with the steel sheet by gradually increasing the pressure along the moving direction of the steel sheet. In the case of such a structure, the steel sheet can gradually receive a high pressure while passing through each cooling body 60 to gradually reduce the thickness of the plating layer.

  Therefore, the thickness of the plating layer can be controlled more precisely by gradually reducing the thickness of the plating layer as it goes from the knife 20 to the cooling part along the moving direction of the steel plate.

  In addition, the cooling unit can improve the plating performance even for a hard-to-plate steel type by rapidly cooling the plating layer while pressurizing the plating layer under a predetermined pressure. In addition, the cooling unit can finally control the surface roughness of the steel sheet plating layer through a cooling roll or a cooling belt disposed at the rear end side end along the traveling direction of the steel sheet. Therefore, a higher quality product can be produced.

  As described above, the plating apparatus of the present embodiment can cool the plating layer more rapidly than the conventional one by bringing the cooling belt cooled by the cryogenic liquid into close contact with the plating layer and cooling it. . Plated steel sheet cooling directly affects the surface quality of the product. If the unsolidified plating layer is contacted with contaminated gas or rolls at the rear end of the equipment, the plated layer must be completely solidified before entering the rear end of the equipment, as this will cause direct surface defects. I must. In the case of the conventional structure, by using a gas or water cooling method, the heat capacity is low and the cooling capacity is lowered. Therefore, it is very long to completely solidify the plating layer by cooling the plated steel sheet to a certain temperature or less. A multi-stage cooling line was required. Therefore, conventionally, since the cooling line is considerably complicated and the equipment scale is enormous, it is difficult to manage the equipment effectively, and surface defects frequently occur. In particular, when the difference between the solidification start temperature and the solidification completion temperature of the plating layer is large, such as an alloy-plated steel sheet in which a large amount of Al or Mg is added to the Zn plating solution, the conventional gas-based system provides sufficient cooling. It is difficult to obtain an effect. Therefore, since the plating layer is not cooled well, a coarse and fragile plating layer structure containing Al and Mg, which are strong oxidation metals, is generated. Bonding occurs, leading to the problem of plating layer cracking and corrosion resistance degradation.

  On the other hand, in the case of the present embodiment, the cooling belt 66 is in direct contact with the plating layer of the steel plate, and the cooling ability by the cryogenic liquid is added to the plating layer, so that the cooling efficiency can be further increased. Thus, the time required for cooling the plating layer can be greatly shortened. Therefore, according to the present embodiment, the cooling rate of the plated steel sheet is increased to 20 ° C./sec or more, and the equipment line of the cooling section can be further reduced. Further, the gas does not directly contact the steel sheet, the occurrence of surface defects can be minimized, and a smaller and uniform surface structure can be obtained to produce a high-quality plated steel sheet. In addition, the generation of dust harmful to the environment can be prevented without using cooling gas.

  In this embodiment, the cooling belt 66 may have a structure in which a pattern is imprinted on the plating layer in the process of pressurizing and cooling the plating layer of the plated steel plate. Here, the pattern may mean a repetitive pattern or pattern.

  Since the plating layer of the plated steel sheet is affected by the surface shape of the cooling belt in contact with the plating layer for cooling, the surface of the plating layer is processed through a structure in which various patterns are formed on the cooling belt and transferred. Can do. Therefore, the cooling belt 66 may be formed with a pattern transferred to the plating layer on the surface. Therefore, in the process where the cooling belt is pressed and adhered to the plating layer to cool the plating layer, the pattern formed on the surface of the cooling belt is held by the plating layer and transferred to the plating layer in the same form as the cooling belt pattern. Pattern is formed.

  In this way, by rapidly bringing the cooling belt into contact with the plated layer of the plated steel plate and rapidly cooling it, the pattern can be easily formed on the plated layer without using a separate pattern forming apparatus.

  Hereinafter, the plating process according to the present embodiment will be described.

  The steel plate plated with molten zinc through the plating bath according to the present embodiment is manufactured as a plated steel plate through a step of moving to the upper portion of the plating bath and adjusting a plating adhesion amount of the steel plate and a step of cooling the steel plate.

  In order to adjust the plating adhesion amount of the steel plate, the plating adhesion amount of the steel plate coming out of the plating bath is primarily controlled by a low-temperature knife that is in contact with the plating layer on the steel plate surface. The amount of plating is secondarily controlled by a low-temperature chill roll that contacts the steel plate surface plating layer at the rear end of the knife.

  The adjustment of the amount of plating applied by the knife and chill roll is performed by detecting the contact load of the knife and chill roll with respect to the steel sheet, and controlling the pressure by moving the knife and chill roll with respect to the steel sheet according to the detected contact load. Can be adjusted to.

  The knife and chill roll are cooled to a low temperature by being supplied with a cryogenic liquid such as liquid nitrogen. The tip portion placed on the knife is cooled to a temperature of 5 ° C. or less by the cryogenic liquid supplied to the knife. Therefore, the plating solution is not fused to the chip part cooled to a low temperature in a state where the chip part is in contact with the plating layer to adjust the amount of plating adhesion. Therefore, the knife can accurately control the plating adhesion amount of the plating layer in a state where the tip portion is physically in contact with the plating layer. In this way, the amount of plating attached to the plating layer of the steel plate coming out of the plating bath is controlled primarily by the knife.

  The chill roll comes into contact with the plating layer of the steel plate, the amount of which is primarily controlled by a knife, and physically pressurizes the plating layer, thereby controlling the amount of plating to be secondarily and precisely controlled.

  The chill roll is also cooled to a low temperature by the cryogenic liquid supplied to the inside, and the surface of the chill roll in contact with the plating layer is cooled to 5 ° C. or lower. Therefore, the plating solution does not adhere to the chill roll surface in a state where the chill roll is in close contact with the plating layer and pressed. Therefore, the thickness of the plating layer of the steel sheet can be adjusted by precisely controlling the amount of plating applied to the plating layer by pressing the chill roll to the plating layer.

  In the process in which the steel sheet is pressed by the chill roll and the plating adhesion amount is controlled, the plating layer of the steel sheet is rapidly cooled by the low temperature chill roll. As mentioned, the chill roll is rapidly cooled while the plating layer in contact with the chill roll is heat-exchanged with the chill roll while being cooled by the cryogenic liquid. As described above, the plated steel sheet may be rapidly cooled at a cooling rate of 20 ° C./sec or more by allowing the chill roll to contact the plated layer to cool the plated layer.

  The steel plate rapidly cooled while passing through the chill roll is rapidly cooled below the set temperature while passing through the cooling section disposed at the rear end of the chill roll.

  In the cooling section, a plurality of units configured to include a cooling roll and a cooling belt as a cooling body are continuously arranged, and the cooling belt of each unit is pressed and adhered to the plating layer on the surface of the steel plate.

  Like the chill roll, the chill roll is cooled to a low temperature by supplying a cryogenic liquid such as liquid nitrogen. The cold air from the cooling roll is applied to the plating layer through the cooling belt to rapidly cool the plating layer.

  The cooling belt is cooled to a low temperature by the cryogenic liquid and the plating layer does not adhere to the cooling belt in a state in which the cooling belt is pressurized to the plating layer.

  The cooling belt cools the plating layer in a state where the plating layer of the steel plate is pressurized to an appropriate pressure. The adjustment of the pressure applied to the cooling belt with respect to the steel plate can detect the contact load of the cooling belt with respect to the steel plate, and the pressure can be precisely controlled by moving the cooling belt with respect to the steel plate according to the detected contact load.

  Therefore, the plated steel sheet that has passed through the chill roll may be cooled by a cooling belt while passing through the cooling section, and may be rapidly cooled to a temperature of 250 ° C. or less at a cooling rate of 20 ° C./sec or more.

  The thickness of the plating layer of the steel sheet is gradually reduced along the moving direction of the steel sheet by pressing the plating layer with the chill roll and the cooling belt in direct contact with the plating amount adjusting process and the plating layer cooling process. The thickness of the plating layer can be controlled more precisely.

  In addition, since the plating layer is cooled under pressure by a chill roll and a cooling belt, not only hot dip galvanization but also the plating properties of difficult-to-plate steel types can be improved.

  Since liquid nitrogen can be gasified in the plating adhesion adjustment process and the plating layer cooling process, the exhaust gas generated in this process passes through the filtration process and then maintains the atmosphere of the reducing gas in the heat treatment furnace (Furnace) or the plated steel sheet cooling process It can be reused as industrial gas.

  Here, in the cooling process of the plated layer of the steel sheet by the cooling belt, a pattern may be formed on the surface of the plated layer of the plated steel sheet.

  While the cooling belt pressurizes and cools the plating layer, the pattern formed on the surface of the cooling belt presses and pressurizes the plating layer. Therefore, the pattern formed on the surface of the cooling belt is directly transferred to the plating layer, and a pattern having the same form as the pattern formed on the surface of the cooling belt is formed on the surface of the plating layer.

  As described above, a pattern having a desired shape can be formed on the surface of the plated steel plate in the process of simply cooling the plated layer.

  While exemplary embodiments of the present invention have been illustrated and described, as described above, various modifications and other embodiments can be made by those skilled in the art. Such modifications and other embodiments are fully contemplated and encompassed by the appended claims and do not depart from the true spirit and scope of the present invention.

10: Plating bath 12: Sink roll 20, 21: Knife 22: Body 23: Rotating body 24: Tip part 25: Drive belt 26, 42, 64: Flow path 27: Step motor 30: Load sensor 32: Control part 34: Drive unit 40: Chill roll 50: Refrigerant supply unit 60: Cooling body 64: Cooling roll 66: Cooling belt 68: Drive cylinder

Claims (20)

Plating bath for hot-plating steel plates;
A wiping portion disposed on one or both surfaces of the steel plate at the rear end of the plating bath along the steel plate traveling direction to control the amount of plating on the steel plate; and one surface of the steel plate at the rear end of the wiping portion along the steel plate traveling direction. Or a cooling part arranged on both sides for cooling the steel sheet,
The cooling unit cools the cooling body by supplying a cryogenic liquid containing liquid nitrogen or liquid helium to the cooling body, and at least one cooling body that closely contacts the plating layer on the surface of the steel plate and cools the plating layer A plating apparatus including a refrigerant supply unit.   The wiping unit includes a knife that contacts a plating layer on the surface of the steel sheet to control the amount of plating, and a coolant supply unit that cools the knife by supplying a cryogenic liquid containing liquid nitrogen or liquid helium to the knife. The plating apparatus according to claim 1.   The wiping part extends in the steel plate width direction at the rear end of the knife along the steel plate traveling direction, and a cryogenic liquid circulates in the inside thereof, and adheres to the plating layer on the steel plate surface to control the amount of plating, thereby removing the steel plate. The plating apparatus according to claim 2, further comprising a chill roll that is rapidly cooled. Plating bath for hot-plating steel plates;
A wiping portion disposed on one or both surfaces of the steel plate at the rear end of the plating bath along the steel plate traveling direction to control the amount of plating on the steel plate; and one surface of the steel plate at the rear end of the wiping portion along the steel plate traveling direction. Or a cooling part arranged on both sides for cooling the steel sheet,
The wiping section includes a knife that contacts a plating layer on the surface of the steel sheet and controls a plating adhesion amount, and a plating that includes a coolant supply section that cools the knife by supplying a cryogenic liquid containing liquid nitrogen or liquid helium to the knife. apparatus.   The wiping part extends in the steel plate width direction at the rear end of the knife along the steel plate traveling direction, and a cryogenic liquid circulates inside, and adheres to the plating layer on the steel plate surface to control the amount of plating and to remove the steel plate. The plating apparatus according to claim 4, further comprising a chill roll that is rapidly cooled.   The knife includes a body that extends in a width direction of the steel sheet and in which a cryogenic liquid circulates inside, and a tip part that is installed at a front end of the body and controls a plating adhesion amount by contacting a plating layer of the steel sheet. The plating apparatus as described in any one of 2 thru | or 5.   The knife extends in the width direction of the steel plate and is rotatably installed, and a rotating body in which a cryogenic liquid circulates inside, and is installed on the outer peripheral surface of the rotating body at intervals along the circumferential direction. A tip portion that controls a plating adhesion amount in contact with the plating layer, and a rotation driving portion that is connected to the rotating body and rotates the rotating body to place the one-side tip portion toward the steel plate surface. The plating apparatus as described in any one of thru | or 5.   The wiping unit is provided in the knife and detects a contact load of the tip part with respect to the steel plate, and controls the pressing force of the tip part against the steel plate by moving the knife with respect to the steel plate by a detection signal of the load sensor The plating apparatus according to claim 6, further comprising a control unit.   The plating apparatus according to claim 6, wherein a tip portion of the knife is cooled to a temperature of −250 to 5 ° C.   The plating apparatus according to claim 6, wherein the tip portion has a structure arranged in parallel to a width direction of the steel plate.   The plating apparatus according to claim 6, wherein the tip portion is structured to be inclined with respect to the width direction of the steel plate.   The plating apparatus according to claim 6, wherein the tip portion is formed by being bent and arranged in a V shape or an inverted V shape along a moving direction of the steel plate.   The wiping unit is provided in the chill roll to detect a contact load of the chill roll with respect to the steel plate, and a control for controlling the pressing force of the chill roll with respect to the steel plate by moving the chill roll with respect to the steel plate by a detection signal of the load sensor. The plating apparatus according to claim 3 or 5, further comprising a section.   The plating apparatus according to claim 3 or 5, wherein the chill roll is cooled to a temperature of -250 to 5 ° C.   The plating apparatus according to claim 3 or 5, wherein the chill roll or the cooling roll has an average surface roughness of 0.1 to 3 um.   The cooling body includes a cooling roll that extends in the width direction of the steel sheet and in which a cryogenic liquid circulates and is pressurized to the plating layer on the surface of the steel sheet to apply cold air. The plating apparatus according to any one of claims 1 to 3, wherein the plating apparatus has a structure arranged at intervals along a direction.   The plating apparatus according to claim 16, wherein the cooling body further includes a cooling belt that is wound and installed between at least two cooling rolls and applies cold air in close contact with the plating layer on the surface of the steel sheet.   The plating apparatus according to claim 17, wherein the cooling belt is cooled to a temperature of -250 to 5 ° C.   The cooling unit is provided in the cooling roll to detect a contact load of the cooling belt with respect to the steel plate, and a pressure applied to the cooling belt with respect to the steel plate by moving the cooling roll with respect to the steel plate by a detection signal of the load sensor The plating apparatus according to claim 17, further comprising a control unit that controls.   The plating apparatus according to claim 16, wherein a pattern to be transferred to the plating layer is formed on a surface of the cooling belt.

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