JPH0247245A - Hot dip coating method using brush roll - Google Patents

Abstract

PURPOSE:To facilitate and speed up switching of production of a plated steel sheet and a cold rolled steel sheet and switching of plating kinds by providing a flow rate controller in plating baths and regulating the flow rate of the plating metal which flows down from slits and is splashed by brush rolls. CONSTITUTION:The plating device is disposed on both sides of the transporting path for the steel sheet 1. The flow rate controllers 15 are provided in the plating liquid 13 to regulate the down flow rate of the plating metal flowing in the lower slits 14. The plating metal flowing down from bath cells 11 is splashed toward the surface of the steel sheet 1 by the brush rolls 16 provided below the bath cells 11 and is stuck to both the surfaces of the steel sheet 1. Only the one plating device is used in case of plating on one side. The kinds of the plating metals to be poured into the respective bath cells 11 are changed in case of applying different platings on the front and rear of the steel sheet 1. The steel sheet is passed through both the plating devices without using said devices in case of producing the cold rolled steel sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hot-dip plating apparatus suitable for dual-purpose manufacturing equipment that can manufacture either cold-rolled steel sheets or plated steel sheets in the same equipment.

[Conventional technology]

When performing hot-dip plating on a steel plate, an apparatus as shown in FIG. 4 is used. That is, the steel plate l to be plated is guided into a pot holding a plating bath 32 by a turndown roll 31.

Then, the traveling direction is bent by the zinc roll 33 in the pot, and the plating is carried out of the plating bath 32 via the support roll 34. Further, the amount of plating metal deposited on the surface of the steel plate 1 is adjusted by the air wiper 35.

In this way, a line for producing plated steel sheets is incorporated into conventional cold-rolled groove sheet manufacturing equipment, making it possible to produce both plated steel sheets and cold-rolled steel sheets with the same equipment. This is proposed in Publication No. 57-177965. FIG. 5 is a diagram showing the equipment.

In this dual-purpose manufacturing facility, two strip passing paths are provided: one in which the steel sheet 1 is immersed in the plating bath 41, indicated by a dashed line, and the other in which the steel plate 1 is bypassed, indicated by a dotted line. ing. There are four shears at the branch points of these boardwalks.
2, a welding machine 43 is placed at the confluence point.

When switching this equipment from a cold-rolled steel plate production process to a plated steel plate production process, the steel plate 1 is cut by the shear 42,
Defreef crawl 44.45. Metsu Ki Bath 41, Jin Chlor 46. Run along the differential reflex crawl 47.48. The steel plate 1 is hot dip plated by passing through a plating bath 41 and welding II! At 43, it is welded to the rear end of the preceding steel plate and sent to subsequent equipment such as a louver.

On the other hand, cutting and
In the case of replacement, the steel plate 1 is cut by the shear 42 and passed directly from the deflation crawler 44 to the deflation crawler 48.

[Problem to be solved by the invention]

However, when switching the board passage, the shear 42
cutting the steel plate 1, aligning the cut steel plate 1 with the differential crawler 44, 45, 47, 48 and the zinc roll 46, connecting the tip of the steel plate 1 to the rear end of the preceding steel plate, etc. Is required.

As a result, the switching work is performed over a long period of time, resulting in poor operating efficiency of the manufacturing equipment.

In addition, when trying to change the type of plating layer formed on the steel plate 1, it is necessary to replace the molten metal in the plating bath 41 or replace the plating bath 41 with one containing a different molten metal. become. In this case, the usual plating bath 41
Since the capacitance is large, it takes a lot of effort and time to change the type of plating layer.

The present invention was developed for the purpose of easily and quickly switching between the plated steel sheet manufacturing process and the cold rolled steel sheet manufacturing process and switching the type of plating.

[Means to solve the problem]

In order to achieve the object, the hot-dip plating apparatus of the present invention uses a continuous heat treatment furnace as a pair of plating apparatus equipped with a bath containing molten plated metal and a brush roll provided below the bath. A slit is formed at the bottom of the bathtub and extends along the axial direction of the brush roll, and the water flows down from the slit and is directed by the brush roll toward the surface of the steel plate. The present invention is characterized in that a flow rate controller is provided inside the bathtub to adjust the flow rate of the plated metal that is splashed away.

[Effect]

The plated metal contained in the bathtub passes through a slit formed in the bottom and flows down onto the circumferential surface of the brush roll.

The plated metal is splashed off by this brush roll and adheres to the surface of the steel plate.

This amount of adhesion can be easily controlled by changing the vertical movement of the flow rate controller, the number of rotations of the brush roll, the horizontal positional relationship between the falling plated metal and the brush roll, and the like. Furthermore, since the amount of adhesion can be adjusted independently for both the front and back surfaces of the steel plate, conditions for differential thickness plating, single-sided plating, different types of plating, etc. can be easily set.

By stopping the application of plated metal by the brush roll, it is possible to easily and quickly switch over to the cold rolled steel sheet production line. Moreover, unlike conventional dip plating, there is no zinc roll immersed in the plating bath, so the steel plate will not be scratched, and dross floating on the surface of the plating bath will not adhere to the surface of the steel plate. do not have. Moreover, since fresh plating metal is always supplied to the surface of the steel plate via the brush roll, the formed plating layer is of excellent quality and stable.

When plating metal is splashed onto the surface of a steel plate from a bathtub, some types of plating metal may be easily oxidized. In such cases, it is preferable to maintain the entire plating apparatus in a non-oxidizing atmosphere. This non-oxidizing atmosphere is also effective in preventing oxidation of the surface of the steel plate, and improves the adhesion of the plated metal to the steel plate.

[Example] Hereinafter, the features of the present invention will be specifically explained through examples with reference to the drawings.

FIG. 1 shows a steel plate being hot-dip plated using a hot-dip plating apparatus according to the present invention.

This hot-dip plating apparatus includes a bath 11 into which plating metal is poured in a molten state by an appropriate means such as a molten metal pump or a siphon. This bathtub 11 has a much smaller capacity than a conventional plating bathtub. The plated metal supplied from the supply pipe 12 to the bathtub 11 is
A plating bath 13 is formed within the tank. Plated metal bathtub 1
1 through the slit 14 formed at the bottom of the bathtub 11
flowing down from

In order to adjust the flow rate of this plating metal, the plating bath 13
A flow rate controller 15 is provided inside the flow rate controller 15.
The opening degree of the slit 14 is changed by vertical movement of the slit 14. Alternatively, the amount of flow can be adjusted by changing the depth (head pressure) of the plating metal in the plating bath 13 and the width of the slit 14.

A brush roll 16 is provided below the bathtub 11. As this brush roll 16, for example, one in which stainless steel wire is implanted on the roll surface is used. The plated metal flowing down from the bathtub 11 is transferred to this brush roll 16.
is thrown toward the surface of the steel plate 10. In addition,
In order to stabilize the flow of the plated metal flowing down from the bathtub 11 to the brush roll 16, it is preferable that the flow nozzle 17 is connected to a slit 14 provided at the bottom of the bathtub II.

These bathtubs11. Plating bath 13. brush roll 16
The plating apparatuses equipped with the above are arranged in pairs on both sides of the conveyance path for the steel plate 1 sent out from the continuous heat treatment furnace. When producing a double-sided plated steel plate, the plated metal splashed off by the brush roll 16 is adhered to both sides of the steel plate 10 using plating devices provided on both sides of the conveyance path.

Furthermore, when manufacturing single-sided plated steel sheets, only one plating device is used. Alternatively, when plating different types of metal on both the front and back sides of the steel plate 1, the type of plating metal injected into each bathtub 1 is changed. The direction in which the plated copper plate I passes may be either upward or downward. When manufacturing a cold-rolled steel sheet, the steel sheet 1 is passed through without using both plating devices.

The thickness of the plating layer formed on the surface of the steel plate 1 can be controlled by changing the amount of plating metal 1 that is splashed off by the brush roll 16.

In this embodiment, the flow rate of the plated metal is adjusted by adjusting the height position of the flow rate controller 15.

Further, the amount of plated metal supplied to the steel plate 1 can also be adjusted by changing the rotation speed of the brush roll 16. Furthermore, by changing the horizontal positional relationship between the falling flow of plated metal and the brush roll 16, the direction of the plated metal thrown off from the brush roll 16 can be changed, and the amount of plated metal adhering to the steel plate 1 can be reduced. It can also be adjusted.

Therefore, the flow rate can be easily controlled, and the thickness of the plating layer formed on the surface of the steel plate 1 can be accurately controlled. Also,
Since the front and back sides of the steel plate 1 can be individually controlled, it is easy to form plated layers with different thicknesses on the front and back sides.

Further, in order to smooth the surface after plating and obtain a uniform plated steel sheet, it is preferable to provide a smoothing device such as a gas cushion above or below the plating device to spray an inert gas onto the surface of the steel sheet 1. . In the example shown in FIG. 1, since the steel plate 1 is being conveyed upward, the gas cushion 18 is provided above the plating section. As such a smoothing device, for example, the present applicant previously filed a patent application in 1983.
The one proposed in No. 2-169512 is used.

The plating bath 13 in the bathtub 11 is replaced by a means such as a molten metal pump or a siphon. This is done by pumping out the plating metal in the 11 and injecting new plating metal. At this time, since the capacity of the bathtub 11 is small, replacement can be done in a short time. Moreover, when this plating bath 13 is replaced only in one of the plating apparatuses, different types of plating layers can be formed on both the front and back surfaces of the steel plate 1.

Among the plated metals splashed off by the brush roll 16, those that do not adhere to the surface of the steel plate 10 are collected from the outlet 24 provided at the bottom of the box body 23 surrounding the brush roll 16, and are sent to the plating bath 13 or plating. It is preferable to adopt a method of circulating the metal to the metal supply source.

When the plated metal is scattered and attached to the surface of the steel plate 1 in this way, the degree to which the plated metal comes into contact with the atmospheric gas during the process from the bathtub 11 to the steel plate 1 increases. Therefore,
When using materials that are susceptible to oxidation as plating metals, it is preferred to maintain an inert atmosphere. On this point, the first
In the hot-dip plating apparatus shown in the figure, the entire apparatus is housed in a chamber 25. An opening 26 is formed only in a part of the side surface of the box body 23 facing the steel plate 1.

Further, a non-oxidizing gas such as nitrogen or argon is sent into the box 23 from the gas introduction pipe 27. A portion of the non-oxidizing gas flows out from the box body 23 into the chamber 25 via the opening 26. Thereby, the plating atmosphere is maintained in a non-oxidizing state, and oxidation of the plating bath 13 and the steel plate 1 is prevented. In addition, a branch pipe 27 branched from the gas introduction pipe 27
A may be opened into the chamber 25 and a portion of the non-oxidizing gas may be directly blown into the chamber 25.

Furthermore, heaters 28 and 29 are provided in the bathtub 11 and the box body 23, respectively, in order to maintain the plating bath 13 at a predetermined temperature and ensure the adhesion of the plated metal splashed by the brush roll 14 to the steel plate 1.

A heater 29 provided within the box body 23 adjusts the viscosity of the plated metal and, in turn, the amount of the plated metal adhered to the steel plate 1 in the hot-dip plating process. In addition, in the cold rolled steel sheet manufacturing process, the plated metal attached to the brush roll 14 is prevented from solidifying, and it also serves to retain heat of the steel sheet 1.

FIG. 2 shows a box with a feature that allows adjustment of the width of the plated metal that is thrown off the brush roll.

This box body 23 has an opening 26 on the side facing the surface of the steel plate 1.
are arranged as a pair on both sides of the conveyance path of the steel plate 1. In order to regulate the length of the opening 26 in the width direction, shutters 21 are provided that move back and forth from both sides toward the center. This shutter 21 is
It is moved by the opening/closing cylinder 22, and the length of the opening 26 in the width direction is adjusted according to the width of the steel plate 1. in this way,
When adjusting the length of the opening 26 in the width direction, the shutter 2 is used to remove the part of the flow of plated metal that has been picked up by the brush roll 16 that exceeds the width of the steel plate 1 to be plated.
1, the plating metal flow exiting the opening 26 corresponds to the width of the steel plate 1. Therefore, plated metal can be supplied to the steel plate 1 without scattering the plated metal around. The plated metal blocked by the shutter 21 is 1. Since the plating metal is recovered through the outlet 24, the usage efficiency of the plated metal is improved.

Furthermore, as shown in FIG. 3, the box body 23 can be provided with a function of adjusting the amount of plating metal deposited. Figure 3 (
As shown in a), the shutter 21 moves horizontally.
In addition, a shutter 21a that moves in the vertical direction is provided, and this shutter 21a is driven by a cylinder 22a. For example, when the upper and lower shutters 21a are brought close to each other, as shown in FIG. The amount of metal can be reduced. Further, the plated metal splashed off by the brush roll 16 reaches the opening 26 in a distribution as shown in FIG. 3(C).

Therefore, even if the height a of the opening 26 is constant, by changing its positional relationship with respect to the brush roll 16, it is possible to adjust the amount of plated metal adhering to the steel plate and, by extension, the thickness of the plated layer. can.

In the hot-dip plating apparatus described above, molten zinc at a temperature of 450°C is used as the plating metal, and this is scattered onto the surface of the steel plate 1 by a brush roll 16 (diameter 300 mm) with a peripheral rotational speed of 300 m/min. A double-sided plated steel plate was manufactured. As a result, a plating layer having a thickness of 20p was uniformly formed on the surface of the steel plate 1. The thickness of the plating layer is the steel plate l.
There was also little variation in the width direction. Also,
By placing up to 18 gas cushions in a nitrogen gas atmosphere, it was possible to prevent oxidation of the plated metal and the surface of the steel plate 1.

Since it was possible to switch from this plated steel sheet manufacturing process to the cold rolled steel sheet manufacturing process by simply stopping the rotation of the brush roll 16, the time required to switch the manufacturing process was only a few minutes. On the other hand, in the method of switching the conveyance path of the steel plate 1 shown in FIG. 4, it took 20 hours to switch the process.

〔Effect of the invention〕

As explained above, in the present invention, by arranging plating equipment equipped with brush rolls that can easily supply and stop the supply of plated metal on both sides of the steel plate conveyance path, the conveyance path can be switched. It becomes possible to freely select the manufacturing process of a double-sided plated steel plate, a single-sided plated steel plate, and a cold-rolled steel plate without having to carry out the above steps. Furthermore, the thickness of the plating layer formed on the surface of the steel plate can be easily adjusted by changing the positional relationship of the flow rate controller with respect to the slit provided at the bottom of the bathtub. Furthermore, since this adjustment is performed independently on both the front and back surfaces of the steel plate, different plating layers of different types and qualities, such as two types, can be easily formed on each of the front and back surfaces. In this manner, according to the present invention, a wide variety of steel plates can be manufactured using a single facility, and the facility has good workability.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a hot-dip plating apparatus according to an embodiment of the present invention, FIG. 2 shows an example of a box surrounding a brush roll of the apparatus, and FIG. 3 shows another example of the box. . On the other hand, FIG. 4 shows a conventional hot-dip plating apparatus, and FIG. 5 shows a combined production facility for plated steel sheets and cold-rolled steel sheets. W4 plate 12: Supply pipe 14 Nislit 16: Brush roll 18: Gas cushion 20; Gas supply port 22.22a: Open/close cylinder 24: Outlet 26: Opening 28.29: Heater 32: Plating bath 34: Support roll 41: Plating bath 11: Bathtub I3: Plating bath 15: Flow rate controller 17: Downstream nozzle 19: Gas jet ports 21, 21a: Shutter 23 Two boxes 25: Chamber 27: Gas introduction pipe 31: Turndown roll 33 Herring roll 35: Air wiper 42: Shear 43: Welding machine 46 Herring crawl 44,
45.47.48: Deflation crawl Figure 1 old Figure 2

Claims (1)

[Claims] 1. Plating equipment equipped with a bathtub containing molten plated metal and a brush roll provided below the bathtub are arranged as a pair on both sides of the conveyance path of the steel plate sent out from the continuous heat treatment furnace, A flow rate controller that forms a slit extending in the axial direction of the brush roll at the bottom of the bathtub, and adjusts the flow rate of the plated metal that flows down from the slit and is splashed by the brush roll toward the surface of the steel plate. A hot-dip plating apparatus characterized in that: is provided inside the bathtub.