KR20130043840A - Eliminating apparatus of galvannealed steel - Google Patents

Abstract

PURPOSE: An ash removing device of a galvanized steel sheet is provided to remove ashes from the surface of molten steel in a plating pot by spraying liquid nitrogen in a snout, thereby improving the surface quality of the steel sheet. CONSTITUTION: An ash removing device of a galvanized steel sheet comprises a plating pot(20), a snout(10), a liquid nitrogen supply device(30), a tilting device(40), and a collecting device(70). The plating pot receives molten zinc. A roller(21) for transferring a steel sheet(50) is rotatably fixed on the plating pot. The snout enters under the surface of the molten zinc of the plating pot and is open to draw out the steel sheet. The liquid nitrogen supply device sprays liquid nitrogen into the snout. The tilting device tilts the snout by applying force from the outer surface of the snout. The collecting device stores ashes transferred from the inside of the snout by a suction nozzle. [Reference numerals] (30) Nitrogen supply device; (41) Hydraulic cylinder; (42) Motor; (70) Collecting device

Description

Ash removal apparatus of galvanized steel sheet {Eliminating apparatus of galvannealed steel}

The present invention relates to an ash removal apparatus of a galvanized steel sheet, and to ash removal of a galvanized steel sheet which can prevent and remove the generation of ash generated during the continuous galvanizing process of a steel sheet which is continuously obtained in the molten zinc in the galvanizing port. Relates to a device.

In recent years, the demand for surface-treated steel sheet has been increasing rapidly due to the increase in the rust-proof guarantee period of automobiles and home appliances, etc. The demand for galvanized steel is on the rise.

Therefore, in order to produce a product with a beautiful surface, in order to minimize the defect of the surface, the quality of the surface quality of the hot-dip galvanized steel sheet in the production line of the hot-dip galvanized steel sheet also needs to be strictly controlled.

Conventional hot-dip galvanized steel sheet has a problem that the flawability caused by the ash generated by the evaporation of the molten zinc in the snout to guide the steel plate continuously in the plating port (Zn pot) in which the molten zinc is accommodated.

Here, the ash is evaporated because the melting point of zinc is 419 ° C. or dross, so that the use temperature is maintained at 450 to 460 ° C., so that ash-type defects occur in the snout and the molten zinc evaporates inside the snout. The condensate of the vapors appears as pointed, linear irregularities that adhere to the surface of the stream.

The ash generated as described above has a problem in that it is attached to the surface of the steel sheet in the snout and transferred by a roller, thereby causing the defect of being continuously picked up.

The present invention has been made to solve the conventional problems as described above, the object of the present invention is to improve the quality of the surface of the steel sheet, to reduce the chipping defects by ash in the continuous galvanizing process and to improve the quality of the steel sheet surface The present invention provides an ash removal apparatus for a galvanized steel sheet that can prevent ash from being removed and remove ash from the hot water surface in a plating port by spraying nitrogen.

The present invention includes the following embodiments in order to achieve the above object.

Ash removal apparatus of the galvanized steel sheet of the first embodiment of the present invention is a plating port for receiving the molten zinc and the roller for transporting the steel plate is fixed to the inside rotatably; A snout which is obtained under the hot water surface of the plating port and is opened to withdraw the steel sheet; A liquid nitrogen supply device for injecting liquid nitrogen into the snout; A tilting device that tilts by applying a force from the outside of the snout; And a collecting device for storing the ash delivered from the suction nozzle for collecting the ash generated inside the snout, wherein the snout has a step formed inward in a section of 300 to 450 mm from the bottom thereof to have a narrow diameter. Has a guide portion having a bellows-shaped flexible structure made of a heat-resistant polyurethane to be tilted by the force transmitted from the tilting device on the outer surface, the liquid nitrogen device is -40 ~ -20 ℃ from the injection nozzle located on the upper side of the guide It is preferable to supply liquid nitrogen of 15 to 35 nm ³ / h as the dew point of.

In the second embodiment of the present invention, the guide portion is formed in a section corresponding to a height of at least 150mm from the hot water surface of the plating port, characterized in that the diameter between the step is within 240 ~ 270mm.

The present invention collects the ash through a narrow section formed to narrow the diameter of a portion of the snout extending up and down to guide the liquid nitrogen in the snout as described above, the liquid nitrogen is guided to the surface of the plating port The ash floating on the top can be removed to prevent the chipping defects caused by the ash, thereby improving the quality of the steel sheet surface.

1 is a side cross-sectional view showing an ash removing device of a galvanized steel sheet according to the present invention;
Figure 2 is a side view showing the outer surface of the snout in the ash removal device of the galvanized steel sheet according to the present invention,
3 is an optimized graph of nitrogen in the ash removal apparatus of the galvanized steel sheet according to the present invention,
4 is an optimization graph of the dew point in the ash removal device of the galvanized steel sheet according to the present invention,
5 is a view comparing the internal temperature of the snout in the ash removal apparatus of the galvanized steel sheet according to the present invention.

Hereinafter, with reference to the accompanying drawings a preferred embodiment of the ash removal apparatus of the galvanized steel sheet in the present invention will be described in detail.

Figure 1 is a side cross-sectional view showing the ash removal device of the galvanized steel sheet according to the present invention, Figure 2 is a side view showing the outer surface of the snout in the ash removal device of the galvanized steel sheet according to the present invention.

1 and 2, the ash removal apparatus of the galvanized steel sheet according to the present invention includes a plating port 20 in which a zinc-melted plating bath is accommodated, and a steel plate 50 in the plating port 20. A snout 10 for guiding, a nitrogen supply device 30 for supplying liquid nitrogen to the snout 10, a tilting device 40 for tilting the snout 10, and the snout 10 And a collecting device 70 for collecting the ash in the shell.

The plating port 20 accommodates a zinc plating bath in which zinc is melted, and a roller 21 for conveying the steel plate 50 guided by the snout 10 is fixed to the inside thereof in a rotatable manner.

The snout 10 is fixed to be inclined downward from the upper surface of the plating port 20 and is formed to transfer the steel sheet 50 continuously transferred from the inside to the plating port 20. To form a dam (13) forming a wall surface inward from the lower end portion for opening, and guide portion (11) inwardly to narrow the diameter is formed.

The dam 13 seals the remaining portion except the space from which the steel sheet 50 is drawn out from the opened lower portion 12 of the snout 10 and forms a wall surface that is bent upwardly into the snout 10. The lower wall of the and the steel plate 50 is formed to partition the opened area to be transferred into the plating port (20).

Therefore, the space between the lower wall surface of the snout 10 divided by the dam 13 and the dam 13 is floated on the hot water surface 62 of the dam 13 or generated inside the snout 10. The ash stores the ash which is separated by tilting.

In addition, when the lower portion 12 of the snout 10 is received below the bath surface 61 of the plating port 20, the dam 13 flows into the lower portion of the snout while the plating bath flows inward. The hot water surface 62 is higher than the hot water surface 61 of the pot 20.

The guide portion 11 is formed as a step which is formed to protrude inward so as to be narrowed in some sections among the sections extending upward and downward of the snout 10 so that the liquid nitrogen supplied from the nitrogen supply device 30 is the dam. A narrow section is formed at the upper side of the dam 13 so as to reach the bath surface 62 of 13, and serves to guide the liquid nitrogen. In addition, the guide portion 11 is formed to have a flexible structure on the outer surface so that it can be tilted by the vibration of the tilting device (40).

Here, the narrow section of the guide portion 11 is preferably formed in a section of 300 ~ 450mm from the lower portion of the snout to the upper side, the lower portion of the snout is obtained below the hot water surface of the plating port to the steel sheet At the time of guiding, it is preferable that the height of the uppermost side of the guide portion 11 is set to a height within 140 to 160 mm at the hot water surface of the plating port. Here, the diameter of the step in the guide portion 11 is within a range of 250 ~ 270mm, the diameter of the snout 10_ has a diameter of at least 300mm.

In addition, the flexible structure in which the force is transmitted from the tilting device on the outer surface of the guide portion 11 is made of a heat resistant (for example, 300 ~ 600 ℃) polyurethane material having a bellows shape tilted by the force applied from the tilting device do,

The tilting device 40 includes a motor 42 for generating power and a hydraulic cylinder 41 for tilting the snout 10 by the power of the motor 42. The motor 42 and the hydraulic cylinder 41 tilt the snout 10 so that an ash floating on the hot water surface 62 of the dam 13 is disposed between the dam 13 and the wall of the snout 10. Move to space.

The nitrogen supply device 30 supplies liquid nitrogen to the inside of the snout 10. Here, the nitrogen supply device 30 includes an injection nozzle 31 for injecting liquid nitrogen at a position higher than the guide portion 11 inside the snout 10. The flow rate of the liquid nitrogen is preferably 15 to 40 Nm ³ / h. This is the result of data derived by the applicant through repeated experiments. This is as shown in FIG. 3 attached.

Figure 3 is a graph showing the results of repeated experiments of the optimized data of liquid nitrogen in the ash removal apparatus of the galvanized steel sheet according to the present invention.

Referring to FIG. 3, in the graph, the vertical axis is the amount of zinc vapor and the horizontal axis is the flow rate of liquid nitrogen, and the flow rate is sequentially increased within the range of 0 to 50 Nm ³ / h to measure the amount of zinc vapor generated to cause ash. As points in the graph shown.

The zinc vapor is generated because the molten zinc is evaporated by the temperature difference between the steel sheet 50 and the plating bath as the steel sheet 50 is obtained in the plating solution. As the zinc vapor condenses at the dew point temperature, ash is generated to contact the surface of the snub 10 or the steel plate 50 or float on the hot water surface 62. Therefore, in this experiment, the amount of ash was predicted through the degree of generation of zinc vapor as described above.

Therefore, Applicant confirmed that the least amount of zinc vapor is generated in the range of 15 ~ 35 Nm ³ / h flow rate of liquid nitrogen as shown in the graph of FIG.

At this time, when the temperature of the steel sheet 50 drawn into the plating bath is less than 470 ℃, the affinity of the steel sheet 50 to the plating bath is lowered, the surface of the steel sheet 50 becomes rough. If the surface of the steel sheet 50 is rough, it may adversely affect the surface of the plating layer. In addition, when the temperature of the steel sheet 50 is 490 ° C. or more, the ash may be increased due to excessive amount of zinc evaporated due to the high temperature of the steel sheet 50. Therefore, it is preferable to keep the temperature of the steel plate 50 at 470-490 degreeC.

In addition, the applicant has measured the range of the dew point temperature at which the zinc vapor is liquefied, as shown in the graph of FIG.

Referring to FIG. 4, the applicant of the present invention was able to obtain data as shown by repeated experiments to find the optimized dew point temperature. Here, the applicant measured that the minimum dew point temperature is -25 ° C and the maximum dew point temperature is -10 ° C when the flow rate of liquid nitrogen is 25 to 45 Nm ³ / h. Therefore, considering the range of the optimized flow rate of the liquid nitrogen, the optimum dew point temperature is preferably -20 ~ -40 ℃.

The collecting device 70 collects and stores ash and zinc vapor generated in the snout 10 from the inside of the snout 10. To this end, a suction nozzle 71 is connected to the pipe by the inner guide part 11 of the snout 10 and connected to the guide part 11 through the pipe.

The collecting device 70 collects the inner mesh or zinc vapor of the snout 10 by, for example, driving a metal pump. At this time, the collection using the metal pump is preferable to adjust the rotation speed in anticipation of the amount of mesh or zinc vapor generated inside. That is, when the amount of zinc vapor generated inside the snout 10 is small, if the rotation speed of the metal pump is high, it may affect the temperature of the steel sheet 50 or the dew point temperature. It is preferable to adjust the rotation speed according to the flow rate.

This is calculated according to the amount of zinc vapor calculated through the above-described optimization data of the flow rate and dew point temperature of the liquid nitrogen, which is not necessarily limited to that shown in Table 1 below.

division Management standard goal Min Max Metal pump 500 rpm 400 rpm 600 rpm Snout Dew point
(℃) -30 -40 -20 N2 flow rate
(Nm ³ / h) 25 15 35

As shown in Table 1, the minimum rotation speed and the maximum rotation speed were set at the flow rate and the dew point temperature of the liquid nitrogen, which is a rotation speed suitable for capturing the zinc vapor calculated in the graphs of FIGS. 3 and 4 described above. It is presented.

The hydraulic cylinder 41 and the motor 42 tilt the outer surface of the snout 10 which is formed flexibly on the outer surface of the snout 10. In this case, the motor 42 is driven to supply power to the hydraulic cylinder 41, and may tilt the outer surface of the snout 10 by the hydraulic cylinder 41. Therefore, the snout 10 is tilted by the action of the motor 42 and the hydraulic cylinder 41 while the ash light generated on the water surface 62 between the dams 13 is tilted by the dam 13. Inflow into the space between the wall surface of the snout 10 and the dam 13 to be separated from the steel sheet 50.

The flexible structure may include a plurality of grooves in which the outer surface of the guide part 11 has different thicknesses so that vibration of the tilting device 40 can be transmitted from the outer surface of the guide part 11 of the snout 10. It is preferable to form.

The present invention includes the configuration as described above, the following will be described in detail the operation of the present invention including the configuration as described above.

First, the steel sheet 50 is continuously obtained in the plating port 20 through the snout 10. At this time, the steel sheet 50 is obtained in the plating bath through the snout 10 in a state heated to a temperature of 470 ~ 490 ℃. In addition, since the end of the snout 10 is obtained in the plating port 20, the bath surface 62 of the plating bath flowing between the dams 13 is the bath surface 61 of the plating port 20. It is in a higher position.

In addition, the nitrogen supply device 30 supplies liquid nitrogen to the inside of the snout ¹⁰ to be injected through the injection nozzle 31 at a flow rate of 15 to 35 Nm ³ / h. At this time, the injection nozzle 31 is installed on the upper side of the guide portion 11 to inject the liquid nitrogen toward the water surface 62 between the dam (13). At this time, the guide part 11 guides the liquid nitrogen injected from the injection nozzle to the water surface 62 of the dam 13.

In addition, the motor 42 is driven to drive the hydraulic cylinder 41 to tilt the snout 10, and the collection device 70 is driven to generate zinc vapor generated inside the snout 10. And ash.

As described above, the nitrogen supply device 30, the collecting device 70, and the hydraulic cylinder 41 are driven, and the steel sheet 50 is supplied to the plating bath by driving the roller 21 in the plating port 20. . Therefore, zinc vapor is generated as zinc of the plating bath is evaporated due to the temperature difference between the plating bath and the steel sheet 50.

This fact can be compared with the conventional snout and the snout to which the present invention is applied as shown in FIG. 5. 5 (a) shows the heat distribution of a conventional snout, and (b) measures the heat distribution of a snout to which the present invention is applied. In the conventional snout, the temperature difference between the part A and the steel plate facing each other is clearly distinguished, and zinc vapor may be condensed by such a temperature difference, thereby causing a lot of ash.

However, in the snout to which the present invention is applied, the symmetrical portions are maintained at the same temperature with the reference numeral A 'and the steel plate therebetween, so that the zinc vapor is less condensed and the generation of ash is prevented and suppressed.

The zinc vapor is sucked by the suction nozzle 71 installed in the section narrowed by the guide part 11 and transferred to the collecting device 70, and floated on the water surface 62 of the dam 11. The ash is moved over the dam 13 by the tilting of the snout 10 to the space between the dam 13 and the snout 10, so that the steel sheet 50 is provided with the hot water surface 62 where the steel sheet 50 is obtained. There is no float and there is no ash adsorbed on the surface of the steel sheet 20 because zinc vapor is continuously collected.

Through such a process, the galvanizing of the steel sheet 50 can be performed continuously, so that the quality of the steel sheet is improved, and defects in the chipping defect due to the ash are not generated.

Although the present invention has been described in detail with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical spirit of the present invention, and such modifications and variations belong to the appended claims.

10: snout 11: guide part 11
12: lower part 13: dam
20: plating port 21: roller
30: nitrogen supply device 31: injection nozzle
41: hydraulic cylinder 42: motor
50: steel plate 61: pot water noodles
62: dam water surface 70: collecting device
71: suction nozzle

Claims (2)

A plating port configured to receive the molten zinc and to rotate the roller for transporting the steel sheet to the inside thereof;
A snout which is obtained under the hot water surface of the plating port and is opened to withdraw the steel sheet;
A liquid nitrogen supply device for injecting liquid nitrogen into the snout;
A tilting device that tilts by applying a force from the outside of the snout; And
A collecting device for storing the ash delivered from the suction nozzle for collecting the ash generated inside the snout,
The snout has a guide portion having a bellows-shaped flexible structure made of a heat-resistant polyurethane so that a step is formed inwardly within a section of 300 to 450 mm from a lower portion thereof to have a narrow diameter, and is tilted by a force transmitted from the tilting device at the outer surface. Have,
The liquid nitrogen device is an ash removal device of the galvanized steel sheet for supplying liquid nitrogen of 15 ~ 35nm ³ / h at a dew point of -40 ~ -20 ℃ from the injection nozzle located above the guide portion. The method of claim 1, wherein the guide portion
The lower part of the snout is located in a section corresponding to a height of at least 150 mm from the tap surface when the bottom of the plating port is obtained under the tap surface, and the ash of the galvanized steel sheet characterized in that the diameter between the steps is within 250 to 270 mm. Removal device.

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