CN110312817B

CN110312817B - Plating apparatus and plating method

Info

Publication number: CN110312817B
Application number: CN201780086979.0A
Authority: CN
Inventors: 金洙永; 权纹栽
Original assignee: Posco Co Ltd
Current assignee: Posco Holdings Inc
Priority date: 2016-12-23
Filing date: 2017-12-22
Publication date: 2021-08-27
Anticipated expiration: 2037-12-22
Also published as: MX2019007631A; CN110312817A; WO2018117755A1; KR101840673B1

Abstract

The present invention relates to a plating apparatus and a plating method for transferring a molten plating solution from a premelt tank to a plating tank, the plating apparatus including: a pre-melting tank for accommodating a molten plating solution; a plating tank for containing a molten plating solution to be plated on a steel sheet; a launder connecting the pre-melting tank and the plating tank to transfer the molten plating bath; a pipe member transferring the molten plating solution of the pre-melting tank to the launder; and a gas supply part supplying gas to the pipe part.

Description

Plating apparatus and plating method

Technical Field

The present invention relates to a plating apparatus and a plating method, and more particularly, to a plating apparatus and a plating method for transferring a molten plating solution from a pre-bath to a plating bath.

Background

In recent years, Hot-dip Galvanized Steel Sheets (GI) and Galvannealed Steel Sheets (GA) have been increasingly demanded as surface-treated Steel Sheets for automobiles, household appliances, and the like because of their excellent corrosion resistance and economical efficiency.

The hot-dip galvanized steel sheet (GI) and the alloyed hot-dip galvanized steel sheet (GA) are formed by dipping a strip steel (strip) to be plated as a plated steel sheet into a plating bath filled with a molten zinc plating bath through a snout (snout) to plate between a sink roll and a stabilizing roll. However, in recent years, a plating apparatus is configured as a two-Pot system (dual Pot system), transfers Molten Zinc (Molten Zinc) or a Molten similar alloy melted in a Pre-melt tank (Pre-melt tank) into a plating tank (Main tank) or work tank (work tank)) through a runner (launcher) having a predetermined inclination, and dips a plated steel sheet in the plating tank to perform plating.

In the continuous hot dip plating process (CGL), it is necessary to receive the amount of plating solution consumed for plating in the plating tank from the pre-bath through the launder. A large ingot (ingot) is put into the pre-melting tank, and the plating solution overflows into the plating tank through the launder so that the plating solution can be supplied, and in this process, it is necessary to maintain the temperature and atmosphere inside the launder to prevent the plating solution from solidifying.

However, the continuous hot dip plating process has a problem that the supply rate of the molten metal is not constant and is slow. In addition, it is difficult to adjust the composition of the plating bath in the plating tank. In addition, oxides generated inside the launder contaminate the molten bath in the plating tank, resulting in surface defects of the plated product. In addition, in order to maintain the temperature inside the launder, it is necessary to use a gas burner, in which case there are many difficulties in the maintenance of the equipment, such as the removal of oxides and the like generated as by-products.

Publication No. 10-2012-0071832 discloses a material cooling delivery device, but still has the problem of dissipating waste heat into the atmosphere.

Disclosure of Invention

Technical problem to be solved

Embodiments of the present invention provide a plating apparatus and a plating method capable of continuously supplying a plating solution of an amount of plating solution consumed in a plating tank from a pre-molten bath without installing an additional gas burner in a flow tank and regardless of overflow (overflow) of the plating solution caused by directly throwing a steel ingot into the pre-molten bath.

(II) technical scheme

According to an aspect of the present invention, there may be provided a plating apparatus including: a pre-melting tank for accommodating a molten plating solution; a plating tank for accommodating the molten plating solution plated on the steel sheet; a launder connecting the pre-melting tank and the plating tank to transfer the molten plating solution; a pipe part transferring the molten plating solution of the pre-melting tank to the launder; and a gas supply part supplying gas to the pipe part.

In the pipe member, an inflow port into which the molten plating bath of the pre-melting tank flows may be immersed in the molten plating bath of the pre-melting tank.

In addition, the inflow port of the pipe member may be located below a half of the level of the molten plating bath contained in the pre-melting tank.

Further, a supply portion of the gas supply member that supplies the gas may be located above a surface of the molten plating solution in the pre-melting tank, and a discharge port that delivers the gas to the pipe member may be located inside the inflow port of the pipe member.

In addition, the gas supplied from the gas supply part may be an inert gas or a non-oxidizing gas.

In addition, the gas supply part may further include a nozzle capable of adjusting a gas flow rate.

In addition, the pipe part may further comprise a connection part connected with the runner and rotatably provided.

In addition, the pipe member may be configured to be movable in an up-down direction.

In addition, the pipe member may be configured to be movable in an up-down direction by an assembly of a rack and a pinion.

In addition, the plating apparatus may further include: a filter filtering impurities in the molten bath transferred from the pre-melting tank to the plating tank.

According to another aspect of the present invention, there may be provided a plating method of transferring a molten plating bath from a pre-melting tank, in which the molten plating bath is generated, to a plating tank, in which a steel sheet is plated with the molten plating bath, wherein gas is supplied to a flow tank, which connects the pre-melting tank and the plating tank to transfer the molten plating bath.

In addition, the temperature of the gas may be set to a temperature of 350 degrees celsius or more and 1300 degrees celsius or less.

In addition, the gas may be an inert gas or a non-oxidizing gas.

In addition, the molten plating bath may be transferred to the launder through a pipe member provided in the pre-melting tank, and the gas may be supplied to an inflow port of the pipe member immersed in the molten plating bath of the pre-melting tank.

In addition, the gas may be supplied to reduce the specific gravity of the molten plating solution inside the pipe member.

In addition, the flow rate of the molten plating solution transferred from the pre-molten bath to the launder may be adjusted using information on the flow rate of the molten plating solution consumed in the plating tank.

In addition, the flow rate of the gas may be adjusted using information on the flow rate of the molten plating solution consumed in the plating tank.

The flow rate of the gas may be two times or more the flow rate of the molten plating solution consumed in the plating tank.

(III) advantageous effects

The plating apparatus and the plating method according to the embodiment of the invention can keep the plating bath level, temperature and composition of the plating tank constant and can be precisely controlled, and thus can improve the quality of plated steel sheets.

In addition, inflow of oxides through the launder is prevented, so that the surface quality of the plated steel sheet can be improved.

In addition, it is not necessary to use a gas burner for maintaining the temperature inside the launder, and the generation of oxides generated at this time can be prevented. Thereby, the maintenance cost of the plating device can be reduced.

In addition, it is possible to manufacture a structure for facilitating the removal and replacement of the nozzle and the pipe member for injecting the high-temperature inert gas, thereby improving the durability in use and having excellent operational stability.

Drawings

Fig. 1 is a diagram schematically showing a plating apparatus 1 according to an embodiment of the present invention.

Fig. 2 is a diagram for explaining a plating process in the plating tank 200.

Fig. 3 is an enlarged view of a gas supply apparatus 400 according to a first embodiment of the present invention.

Fig. 4 is an enlarged view of a gas supply device 401 according to a second embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments described below are examples provided to fully convey the concept of the present invention to those skilled in the art to which the present invention pertains. The present invention is not limited to the embodiments described below, and may be embodied in other forms. In order to clearly explain the present invention, portions irrelevant to the explanation are omitted from the drawings, and the width, length, thickness, and the like of the components may be exaggerated in the drawings for convenience. Like reference numerals refer to like elements throughout the specification.

Referring to fig. 1, a plating apparatus 1 according to an embodiment of the present invention includes: a Premelt tank (Premelt Pot)100 that melts Zinc to generate Molten Zinc (Molten Zinc) as a Molten plating bath or accommodates the Molten plating bath; a plating tank (Main Pot) or Working Pot) 200 containing molten zinc plated on a steel plate; and a Launder (Launder) 300 between the pre-melting tank 100 and the plating tank 200.

On the other hand, the plating liquid used in the plating apparatus according to the embodiment of the present invention is not limited to molten zinc. Various plating solutions including, for example, zinc (Zn), aluminum (Al), or magnesium (Mg) may be used in the plating apparatus.

The steel Ingot (Ingot) I is put into the pre-melting tank 100 and dissolved in the plating bath.

The flow cell 300 serves to connect the pre-melting tank 100 and the plating tank 200 to transfer the plating solution, and may be provided to have an inclination. In this case, the inflow height of the plating solution from the pre-melting tank 100 is set to be higher than the outflow height of the plating solution from the plating tank 200 so that the plating solution can move to the inside of the plating tank 200 by potential energy.

Fig. 2 is a diagram for explaining a plating process in the plating tank 200.

Referring to fig. 2, molten zinc adheres to the surface of the strip S when the strip S heat-treated in an annealing furnace (not shown) leaves the coating bath 200 after flowing into the coating bath of the coating bath 200 through a nose 210. The molten zinc coated strip S is changed in direction in the coating bath 200 by sink rolls 220 and guided to move vertically by guide rolls 230.

The coating layer coated on the surface of the strip S while passing through the coating bath 200 is adjusted to an appropriate thickness by gas or the like sprayed at a high speed by the gas knife 240, then cooled and solidified while passing through a cooling device (not shown), and then changed in direction by an upper roller (not shown) and moved to the next process.

Referring to fig. 3, the gas supply apparatus 400 according to the first embodiment may include: a pipe member 410 containing a cleaning plating solution; a gas supply part 420 supplying gas to the inside of the tube part 410; and a filter 430 filtering impurities in the plating solution flowing into the launder 300.

The pipe member 410 may have a hollow pipe shape, one side of which is opened to form an inlet 411 and the other side of which is opened to form an outlet 412, and a duct 413 connecting the inlet 411 and the outlet 412 may be formed. For example, the pipe member 410 may be disposed in the up-down direction such that the inflow port 411 is immersed in the plating bath.

Also, the inflow port 411 may be located at the bottom of the pre-melting tank 100 to accommodate a clean plating bath therein. Further, the outflow opening 412 may be located at a position higher than the plating bath level L and connected to the flow cell 300.

Also, the pipe part 410 may be made of metal or nonmetal.

In addition, the volume of the part of the pipe member 410 immersed in the plating bath may be selected according to the amount of the plating solution to be supplied. That is, in the case where the inner diameter of the pipe 413 is determined in advance, the immersion depth H-H of the pipe member 410 may be selected according to the amount of plating solution to be supplied.

Also, the inner diameter and the dipping depth H-H of the pipe 413 may be prepared to ensure a pumpable lift H. For example, the impregnation depth H-H may be set to more than half the total height H. Preferably, the impregnation depth H-H may be set to 70% or more of the total height H. In this case, the total height H can be calculated by the height difference between the inflow opening 411 and the outflow opening 412.

Also, the lift h can be adjusted to satisfy the distance between the plating bath level L and the outflow port 412. The drawing shows a state in which the plating bath inside the pipe member 410 is higher than the outflow port 412.

The gas supply member 420 is extended such that one side thereof is disposed outside the plating bath and the other side thereof is disposed inside the pipe member 410, so that high-temperature inert gas or non-oxidizing gas can be dispersed into the pipe 413 containing the clean plating bath.

Also, the supply part of the gas supply member 420 that supplies the gas may be located above the plating bath surface, and the discharge port that delivers the gas to the tube member 410 may be located inside the inflow port 411 of the tube member 410. For example, the gas supply part 420 may be configured to include a U-shape bent downward such that the discharge port is directed upward. In this case, the gas discharged through the discharge port can move in the pipe 413 in such a manner that bubbles rise in the plating bath.

The discharge port may be disposed at a higher position inside the inflow port 411 of the tube member 410. Accordingly, the gas discharged through the discharge port may be prevented from flowing to the outside of the tube member 410.

The gas supply part 420 supplies high-temperature inert gas to the inside of the pipe part 410 to reduce the density of the plating bath contained in the pipe 413, so that the plating solution can be supplied into the plating tank 200 through the flow cell 300.

Specifically, when high-temperature inert gas is supplied to the inside of the pipe member 410 containing the cleaning plating solution, the plating solution in the pipe 413 and the inert gas injected through the inflow port 411 are mixed with each other to reduce the specific gravity per unit volume of the plating bath. As a result, the pressure of the plating bath inside the pipe member 410 is lowered, and therefore the plating bath inside the pipe member 410 is raised by the pressure of the plating bath outside the pipe member 410, so that the lift h can be secured.

Also, the gas supply part 420 may include a nozzle 421 capable of adjusting the flow rate of the inert gas injected into the plating bath.

The supply flow rate of the inert gas is correlated with the discharge flow rate of the plating bath supplied to the plating tank 200. That is, the gas supply part 420 controls the flow rate of the high-temperature inert gas using the nozzle 421, so that the supply flow rate of the plating solution supplied to the plating bath 200 can be adjusted.

For example, when the head H is half the total height H, it is necessary to supply the inert gas at a flow rate more than twice as large as the flow rate at which the plating solution is to be supplied.

On the other hand, the temperature of the inert gas injected through the gas supply part 420 may be between 350 degrees celsius and 1300 degrees celsius. Also, the plating device 1 may include a boiler (not shown) capable of adjusting the temperature of the inert gas.

The gas supply part 420 may heat the supplied inert gas from 350 degrees celsius or more to 1300 degrees celsius or less, which is a volatilization temperature of zinc of the plating bath components, to spray the inert gas to the pipe part 410.

In addition, the high-temperature inert gas can increase the available lift h, and can also perform a heat-retaining function to prevent the solidification of the plating bath when the plating bath mixed with the inert gas passes through the long flow tank 300. In addition, the high-temperature inert gas can prevent the oxidation phenomenon of the plating bath to prevent surface defects of the strip S that may be caused by the oxidized plating bath. In addition, maintenance costs can be reduced as compared with the conventional case of operating the oxidizing gas burner inside the flow cell 300 by appropriately adjusting the temperature of the supply gas.

In addition, when the gas supply part 420 is used, a continuous plating process may be performed. In the continuous plating process, the plating tank 200 may receive clean plating solution from the pre-melting tank 100 in an amount of the plating solution consumed in the plating tank 200 to plate the strip S. And the amount of plating solution supplied in the continuous plating process may be automatically controlled or manually controlled according to the judgment of an operator.

A filter 430 may be provided at a connection portion of the pipe member 410 and the flow cell 300 to prevent impurities in the plating bath inside the pre-melting tank 100 from being mixed into the plating tank 200. And the filter 430 may be formed in a mesh shape, for example, impurities in the plating bath may be blocked by a mesh of 50 μm or more and 5mm or less. And the filter 430 may be used in a state of being heated to a high temperature between 400 and 700 degrees celsius or using ultrasonic waves to prevent adsorption of impurities.

In order to check the performance of the gas supply apparatus 400, the results of the check performed in the laboratory are shown in table 1.

In Table 1, the time is based on the time required to fill a 2l bathtub, and it is assumed that the specific gravity of the molten zinc is 6.5g/cm³The supply capacity of molten zinc was tested.

[ Table 1]

According to the above experimental results, when the pipe member 410 having the outer diameter of 50mm and the inner diameter of 30mm was used and the immersion depth H-H in the plating bath was 900mm, the volume of the portion immersed in the plating bath was 636cm²At this time, when 5 l/min of gas is injected into the pipe member 410, about 80 l/hr of plating solution can be supplied. Further, the specific gravity was 6.5g/cm³In the case of the molten zinc of (3), the plating solution can be supplied at an efficiency of 500 kg/hr.

Referring to fig. 4, the gas supply device 401 according to the second embodiment can adjust the immersion depth H-H. That is, the position or depth of the pipe member 410 may be adjusted.

For example, the pipe part 410 may be provided to be movable up and down by means of a rack and pinion. The rack 415 may be disposed on one side of the pipe part 410 and the pinion 416 may be disposed on one side of the pre-melt tank 100. And the pinion gear 416 may be disposed to be electrically connected to the motor 417 to be rotated by the power of the motor 417. Further, a rail may be provided outside the pipe member 410 or inside the pre-melt tank 100 to guide the up-and-down movement of the pipe member 410.

In addition, the positions of the rack 415 and the pinion 416 may be changed. That is, the pinion gear may be provided at one side of the pipe part 410, and the rack gear 415 may be provided at one side of the pre-melt tank 100.

In addition, the up-down position of the tube member 410 may be changed in other different ways than shown in fig. 4. For example, the pipe member 410 may be configured such that its upper and lower positions are changed by a cylinder, a chain, or other gear combination.

In addition, the gas supply means 401 may be arranged such that the connection portion 414 of the tube member 410 and the flow cell 300 may be varied. For example, when the up-down position of the pipe member 410 is changed, the coupling angle with the runner 300 may be changed.

The connection portion 414 may be provided as a rotatable structure. For example, the connecting portion 414 may be provided as a hinge structure.

The invention has been described with reference to an embodiment shown in the drawings, which are intended to be exemplary only, and it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof. The true scope of the invention should, therefore, be determined only by the following claims.

Claims

1. A plating apparatus comprising:

a pre-melting tank for accommodating a molten plating solution;

a plating tank for accommodating the molten plating solution plated on the steel sheet;

a launder connecting an upper portion of the pre-melting tank and the plating tank to transfer the molten plating solution;

a pipe member, an upper portion of which is connected to the launder, an inflow port into which the molten plating solution flows being immersed in the molten plating solution of the pre-melting tank to guide the molten plating solution of the pre-melting tank to the launder; and

a gas supply member that supplies an inert gas or a non-oxidizing gas at a temperature of 350 degrees Celsius or more and 1300 degrees Celsius or less to the tube member.

2. The plating apparatus according to claim 1,

the inflow port of the pipe member is located below half of the level of the molten plating bath contained in the pre-melting tank.

3. The plating apparatus according to claim 1,

the supply part of the gas supply member that supplies the gas is located above the surface of the molten plating solution in the pre-melting tank, and the discharge port that delivers the gas to the pipe member is located inside the inflow port of the pipe member.

4. The plating apparatus according to claim 1,

the gas supply part further includes a nozzle capable of adjusting a gas flow rate,

the pipe member is provided to be movable in an up-and-down direction, and further includes a connection portion connected to the runner and rotatably provided.

5. The plating apparatus according to claim 4,

the pipe member is provided to be movable in an up-and-down direction by an assembly of a rack and a pinion.

6. A plating apparatus according to claim 1, further comprising:

a filter filtering impurities in the molten bath transferred from the pre-melting tank to the plating tank.

7. A plating method comprising transferring a molten plating bath from a premelt tank in which the molten plating bath is generated to a plating tank in which a steel sheet is plated with the molten plating bath,

wherein a launder that transfers the molten plating bath from an upper portion of the pre-melting tank to the plating tank and a pipe member that guides the molten plating bath in the pre-melting tank to the launder are provided,

and supplying an inert gas or a non-oxidizing gas at a temperature of 350 degrees celsius or more and 1300 degrees celsius or less to the inside of the pipe member immersed in the pre-melting tank.

8. The plating method according to claim 7,

adjusting the flow of molten plating solution transferred from the pre-molten bath to the launder using information on the flow of molten plating solution consumed in the plating bath.

9. The plating method according to claim 7,

adjusting the flow rate of the gas using information on the flow rate of the molten plating solution consumed in the plating tank.

10. The plating method according to claim 9,

the flow rate of the gas is two or more times the flow rate of the molten plating solution consumed in the plating tank.