JP2013091828A - Hot dip metal plating method and hot dip metal plating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress plating metal droplets from adhering to a strip after wiping in a molten metal plating line using a gas wiping method and to eliminate a complicated maintenance work related to production equipment and molten metal plating. Providing equipment.
SOLUTION: A strip is continuously drawn out from a plating metal bath, and excess plating metal adhering to the strip surface is squeezed out by a gas sprayed from the wiping nozzle toward the strip surface to adjust the amount of plating metal adhesion. When the molten metal plating is performed using the gas wiping method, a bath support roll for vertically supporting the strip is disposed above the wiping nozzle, and the wiping nozzle is disposed above the wiping nozzle. A shield net is provided along the strip surface to the position where the above-mentioned support roll on the bath is disposed, and a rectifying plate is provided between the wiping nozzle and the bath surface of the plating metal bath. Is prevented from adhering to the strip surface.
[Selection] Figure 1

Description

  The present invention relates to a molten metal plating method and a molten metal plating apparatus using a gas wiping method, and a molten metal plating method for suppressing plating metal splashes caused by gas wiping from adhering to a strip as a material to be plated, and The present invention relates to a molten metal plating apparatus suitable for carrying out the method.

  In a molten metal plating line, a gas wiping method is widely applied as a means for adjusting the amount of plating metal attached to a material to be plated. In the molten metal plating line using the gas wiping method, as shown in FIG. 2, the strip S (material to be plated) immersed in the plating metal bath 1 is usually supported from the plating metal bath 1 with the support roll 7 on the bath. The excess plating metal adhering to the strip S is squeezed off by blowing the gas 3 ejected from the wiping nozzle 2 onto the surface of the strip S while pulling up vertically. At that time, a metal plating layer having a desired adhesion amount is formed on the surface of the strip S by adjusting the gas pressure of the gas 3 ejected from the wiping nozzle 2 to adjust the amount of plating metal to be squeezed down.

  As described above, in the gas wiping method, it is possible to adjust the plating metal adhesion amount of the material to be plated with relatively simple equipment. However, in the molten metal plating line using the gas wiping method, it has been regarded as a problem that the plating metal splash due to the gas ejected from the wiping nozzle adheres to the surface of the strip. As shown in FIG. 2, a part of the gas 3 ejected from the wiping nozzle 2 collides with the surface of the strip S, and then becomes an air flow 3 a that goes downward along the strip S. Collide with. Here, if the pressure of the gas 3 ejected from the wiping nozzle 2 is relatively high, the gas colliding with the bath surface 1a of the plating metal bath 1 also becomes a high pressure, so that the bath surface 1a of the plating metal bath 1 is disturbed, Plated metal splash 4 (4a, 4b) is generated. The gas that has collided with the bath surface 1a of the metal bath 1 becomes an air flow 3b that rises in the space opposite to the side where the strip S is arranged in the space provided on both sides of the wiping nozzle 2. Along with the rising airflow 3b, the plated metal splash 4b also rises. Part of the plated metal splash 4b that has risen in this manner adheres to the surface of the strip S after the amount of plated metal deposition is adjusted by wiping through the space provided in the upper part of the wiping nozzle 2.

If plating metal splashes adhere to the strip surface after the plating metal adhesion amount is adjusted, the appearance of the strip and the uniformity of the plating thickness are impaired. Therefore, in order to ensure the quality of the strip as the final product, it is essential to take measures for solving the above-mentioned problems caused by the plating metal splashes.
Here, if the pressure of the gas ejected from the wiping nozzle is sufficiently low, the gas colliding with the bath surface of the plating metal bath also becomes low pressure, and the disturbance of the bath surface of the plating metal bath is suppressed. Occurrence can be suppressed. However, if the pressure of the gas ejected from the wiping nozzle is lowered, the amount of gas blown to the surface of the strip is limited and the wiping effect becomes insufficient, and it becomes difficult to achieve the target adhesion amount. Such a problem becomes apparent as the strip conveyance speed of the molten metal plating line increases. On the other hand, if the pressure of the gas ejected from the wiping nozzle is lowered and the strip conveyance speed is sufficiently low, the above problem can be solved. However, the reduction of the strip conveyance speed causes a decrease in productivity.

In recent years, from the viewpoint of productivity, it is not preferable to reduce the pressure of the gas ejected from the wiping nozzle while further increasing the strip conveyance speed is required.
In view of these problems, Patent Document 1 proposes a method for preventing adhesion of molten metal droplets to a strip surface during molten metal plating, characterized in that a filter is provided above the wiping nozzle along the strip surface. Has been. And in patent document 1, it is supposed that the adhesion to the strip surface of the plating metal splash from a plating metal bath can be prevented reliably by providing a filter along a strip surface above a wiping nozzle.

  Here, an embodiment of the method proposed in Patent Document 1 is shown in FIG. In FIG. 3, 1 is a plating metal bath, S is a strip that is pulled up vertically from within the plating metal bath 1, 2 is a slit-shaped wiping nozzle installed horizontally on both sides of the strip S, and 2A is above the wiping nozzle 2. In addition, a wiping nozzle gas (air) supply main pipe horizontally arranged outside the wiping nozzle 2 (the direction opposite to the direction facing the strip S), 2B is the wiping nozzle 2 and gas supply main pipe Gas supply piping connected between 2A, 10 is an alloying furnace for heating and alloying the strip S, 20 is a metal plate attached between the wiping nozzle 2 and the gas supply main 2A, 30 is a snout, and 40 is a filter provided between the gas supply main 2A and the lower part of the alloying furnace 10.

  In the method proposed in Patent Document 1, the wiping nozzle 2 rises with the airflow 3b rising in the space opposite to the side where the strip S is arranged in the space provided on both sides of the wiping nozzle 2. Plated metal splashes that are to adhere to the surface of the strip S through the space provided in the upper portion are shielded by the filter 40. Further, when the filter 40 is a complete shielding plate, the vicinity of the strip S after wiping is depressurized by the rising air flow caused by the chimney effect of the alloying furnace 10, and accordingly, the turbulent air flow from the side surface of the strip S toward the inside May occur, and metal plating splashes may adhere to the strip S. Therefore, in the method proposed in Patent Document 1, only the metal plate 20 attached between the wiping nozzle 2 and the gas supply main pipe 2A is a complete shielding plate, and the filter 40 above the metal plate 20 is a filter structure. It is said.

JP-A-5-306449

  As described above, according to the method proposed in Patent Document 1, even when plating metal splashes from the plating metal bath are generated in association with increasing the gas pressure from the wiping nozzle, Further, adhesion of the plating metal splash to the strip surface can be prevented. Therefore, it is possible to suppress the adhesion of the plated metal droplets to the strip surface without drastically reducing the strip conveying speed, and the effect of improving the quality of the strip can be expected without reducing the productivity. However, in the method proposed in Patent Document 1, there is a problem in that plating metal splashes are deposited on a metal plate provided under the filter.

  As shown in FIG. 2, when the gas 3 ejected from the wiping nozzle 2 collides with the surface of the strip S, the excessive plated metal that has been squeezed becomes plated metal splashes 4a and 4b along the flow of the air flow. Carried. The plated metal splash 4b generated at the time of wiping mainly travels in the direction opposite to the traveling direction of the strip along the strip S and is scattered by the airflow rising again. As shown in FIG. 3, the presence of the metal plate 20 has an effect of preventing the intrusion of metal splashes that do not reach the filter 40, but the metal plate 20 is curved, so that the splashes are likely to rise along the curved surface. When the 40 mesh is small, the mesh is likely to be clogged, and when the mesh is large, there is a problem that it is easy to enter the mesh. In addition, among the scattered metal splashes, the metal splashes 4 a that spread upward are mainly deposited on the metal plate 20.

  If the plating metal droplets deposited on the metal plate 20 are left in this manner, they will fly again with an air flow that changes depending on the operating conditions of the metal plating line, and will adhere to the surface of the strip S after wiping. Therefore, in the method proposed in Patent Document 1, it is necessary to frequently remove the plating metal splashes deposited on the metal plate 20, resulting in complicated maintenance work.

  The present invention advantageously solves the above-described problems of the prior art, and suppresses adhesion of plating metal droplets to a strip after wiping in a molten metal plating line using a gas wiping method, as well as production equipment. The purpose is to eliminate troublesome maintenance work.

  In order to solve the above-mentioned problems, the present inventors diligently studied a method capable of eliminating troublesome maintenance work in a molten metal plating line using a gas wiping method. As a result, as shown in FIG. 1, a shielding net 5 is provided from the position where the wiping nozzle 2 is disposed to the position where the above-mentioned bath support roll 7 is disposed along the surface of the strip S, and the wiping nozzle 2 and the It has been found that by providing the rectifying plate 6 between the bath surface 1a of the plating metal bath 1, it is possible to prevent plating metal splashes from adhering to the strip S surface during molten metal plating.

  That is, in the prior art shown in FIG. 3 (method proposed in Patent Document 1), the metal plate 20 provided below the filter 40 and attached to the wiping nozzle 2 is not a complete shielding plate but a shielding net. By this, it discovered that it could suppress effectively that a metal-plating metal droplet accumulates in the site | part which concerns. In the prior art shown in FIG. 3, if the metal plate 20 is used as a shielding net together with the filter 40, the plating metal splash passes through the shielding net without depositing on the portion where the metal plate 20 is disposed, and the plating metal bath 1. Fall into. In addition, as shown in FIG. 3, the installation position of the upper part of the shielding net is affected by the rising air current due to the tunneling effect of the alloying furnace 10 and installed in the furnace. Since there was also a problem that metal splashes were scattered, as a result of investigation, it was found that scattering of metal splashes into the furnace can be suppressed by providing a shielding net up to the position where the on-bath support roll is disposed.

  As described above, in the prior art shown in FIG. 3, if the metal plate 20 is a shielding net, it is possible to suppress deposition of plating metal splashes, which is a problem when the metal plate 20 is a complete shielding plate. . However, when the metal plate 20 is used as a shielding net, the effect of suppressing the plating metal droplets from adhering to the surface of the strip S is inferior to the case where the metal plate 20 is a complete shielding plate. Therefore, the present inventors proceeded with investigations on supplementary means for suppressing plating metal droplets from adhering to the surface of the strip S. As a result, it has been found that by providing a rectifying plate between the wiping nozzle 2 and the bath surface of the plating metal bath 1, it is possible to effectively suppress the plating metal splashes rising along with the air flow 3b from adhering to the surface of the strip S. did.

The gist of the present invention is as follows.
[1] The strip is continuously drawn out from the plating metal bath, and excess plating metal adhering to the strip surface is squeezed out by a gas sprayed from the wiping nozzle toward the strip surface to adjust the amount of plating metal adhesion. In the molten metal plating method using the gas wiping method, a support roll on the bath for vertically supporting the strip is disposed above the wiping nozzle, and the strip surface is disposed above the wiping nozzle. In addition, a shielding net is provided up to the position where the above-mentioned support roll on the bath is disposed, and a rectifying plate is provided between the wiping nozzle and the bath surface of the plating metal bath, so that the plating metal splashes are generated during the molten metal plating. A molten metal plating method characterized by preventing adhesion to a strip surface.

[2] The molten metal plating method according to [1], wherein an angle formed by the rectifying plate and the bath surface of the plating metal bath is 0 ° or more and 60 ° or less.

[3] A plating metal bath and a surplus plating metal adhering to the strip surface are squeezed out by jetting gas toward the surface of the strip drawn continuously from the plating metal bath, thereby reducing the amount of plating metal adhesion. A molten metal plating apparatus comprising: a wiping nozzle to be adjusted; and a bath support roll disposed vertically above the wiping nozzle and vertically supporting a strip drawn continuously from the plating metal bath. A shielding net disposed upward from the disposition position along the strip surface to the disposition position of the on-bath support roll, and a current plate disposed below the wiping nozzle and above the plating metal bath And prevents plating metal splashes from adhering to the strip surface during molten metal plating. Molten metal plating apparatus.

[4] The molten metal plating apparatus according to [3], wherein an angle formed by the rectifying plate and the bath surface of the plating metal bath is 0 ° or more and 60 ° or less.

  According to the present invention, in a molten metal plating line using a gas wiping method, it is possible to prevent plating metal splashes from adhering to a strip after wiping, and to greatly reduce troublesome maintenance work related to production facilities. . Therefore, it becomes possible to produce a high-quality strip stably industrially without reducing the productivity, and there is a remarkable industrial effect.

It is sectional drawing which shows typically the molten metal plating apparatus of this invention to which the gas wiping method is applied. It is sectional drawing which shows typically the normal molten metal plating apparatus to which the gas wiping method is applied. It is a perspective view which shows the conventional molten metal plating apparatus to which the gas wiping method is applied.

Hereinafter, the present invention will be described in detail.
An example of the molten metal plating apparatus of the present invention is shown in FIG. As shown in FIG. 1, the molten metal plating apparatus of the present invention is configured to inject a gas 3 toward the surface of a plating metal bath 1 and a strip S continuously drawn from the plating metal bath 1. A wiping nozzle 2 is provided for adjusting the amount of plating metal adhesion by squeezing off excess plating metal adhering to the substrate. 7 is a support roll on the bath for vertically supporting the strip S drawn continuously from the plating metal bath 1, and the support roll 7 on the bath is disposed above the wiping nozzle 2. In addition, 7a is a bath support roll support. As the wiping nozzle 2, for example, a slit-like wiping nozzle and a long wiping nozzle having a length direction in the width direction of the strip S can be used. Then, a metal plating layer having a desired adhesion amount is formed on the surface of the strip S by adjusting the gas pressure of the gas 3 ejected from the wiping nozzle 2 to adjust the amount of plating metal to be squeezed down. The molten metal plating apparatus of the present invention has a wiping nozzle gas (air) supply main pipe (not shown) and a gas supply pipe (not shown) as in the prior art shown in FIG. Although the position is not particularly limited, by setting the outer side of the shielding net 5 described later (the side far from the strip S), it is possible to prevent metal splashes from being deposited on the upper part of the shielding net 5 and efficiently described later. Metal splashes can be collected at the bottom of Further, similarly to the prior art shown in FIG. 3, an alloying furnace (not shown) may be provided above the wiping nozzle 2.

  The above structure is the same as that of a normal molten metal plating apparatus using the gas wiping method. However, in addition to the above, the molten metal plating apparatus of the present invention is further stripped upward from the position where the wiping nozzle 2 is disposed. The shield net 5 is disposed along the surface to the position where the on-bath support roll 7 is disposed, and the rectifying plate 6 is disposed below the wiping nozzle and above the plated metal bath 1. Note that at least one of each of the wiping nozzle 2, the shielding net 5, and the current plate 6 is disposed on both sides of the surface of the strip S.

  As described above, when the gas 3 ejected from the wiping nozzle 2 is caused to collide with the surface of the strip S, the surplus squeezed plating metal is transported along the flow of airflow as plating metal droplets. The plated metal splash generated during wiping mainly travels in the direction opposite to the traveling direction of the strip S along the strip S as indicated by 4b in the figure and is scattered by the airflow 3b rising again.

  Therefore, in the present invention, the plating metal splash 4b rising together with the air flow 3b is formed by the shielding net 5 disposed upward from the position where the wiping nozzle 2 is disposed to the position where the bath support roll 7 is disposed along the strip S surface. Then, adhesion to the surface of the strip S after the plating metal adhesion amount is adjusted by wiping through the space provided in the upper part of the wiping nozzle 2 is prevented.

  When the shielding net 5 is provided as described above, the plated metal splash 4b rising together with the air flow 3b is captured (collected) by the shielding net 5 when attempting to pass through the space provided above the wiping nozzle 2. In order to effectively prevent the plating metal splash 4b from passing through the space provided above the wiping nozzle 2, a shielding net 5 should be installed over the entire space provided above the wiping nozzle 2. Is preferred. The length of the shielding net 5 in the width direction (the same direction as the width direction of the strip S) is preferably equal to or greater than the width of the strip S.

  Further, among the plating metal splashes generated at the time of wiping, the plating metal splashes 4a that diverge upward in a small amount mainly reach the position of the lower part 5b of the shielding net 5, but most of these plating metal splashes 4a are the shielding net 5 It is discharged through the mesh of the shielding net 5 without being deposited on the lower part 5b of the screen.

  The mesh size of the shielding net 5 is preferably about 0.5 to 3.0 mm. If the mesh size of the shielding net 5 is less than 0.5 mm, the plating metal splash may be clogged with the mesh of the shielding net 5. The shielding net 5 needs to be removed by periodically cleaning and capturing (collecting) the plated metal splash or replacing the shield net 5. However, if the plated metal splash becomes clogged with the mesh of the shielding net 5 Therefore, it is necessary to frequently clean or replace the shielding net 5, which complicates maintenance work and increases costs. Further, when the mesh size of the shielding net 5 is less than 0.5 mm, the plating metal splash 4a (plating metal splash 4a that diverges upward during wiping) is deposited in the lower portion 5b of the shielding net 5 without being discharged. There is a fear.

  On the other hand, if the mesh size of the shielding net 5 exceeds 3.0 mm, the function of capturing (collecting) the plated metal splash 4b is reduced, and the plated metal splash 4b passes above the wiping nozzle 2 and passes through the strip S. It becomes difficult to suppress the phenomenon that adheres to the surface. Further, in the present invention, the mesh of the lower part 5b of the shielding net 5 is less than the meshes of other parts in order to avoid as much as possible the plating metal splashes 4a that diverge upward during wiping from accumulating on the lower part 5b of the shielding net 5. May be larger. From such a viewpoint, for example, the mesh size of the lower portion 5b of the shielding net 5 is preferably 3.0 to 20 mm, and the mesh size of other portions is preferably 0.5 to 3.0 mm. The height at which the mesh size of the lower part 5b of the shielding net 5 is increased (the height from the lower part 5b of the shielding net 5) depends on the installation height of the rectifying plate 6, but is preferably 50 mm or less, and more preferably 20 mm or less. .

  The material of the shielding net 5 is not particularly limited, and any conventionally known net such as metal or resin can be applied. However, from the viewpoint of strength, a metal such as stainless steel is preferable.

  As described above, the present invention using the shielding net 5 can be said to be an effective solution to the problem seen in the prior art shown in FIG. 3, that is, the problem of plating metal droplets depositing on the metal plate 20 having a complete shielding structure. Further, when the alloying furnace is provided above the wiping nozzle 2 (and the on-bath support roll 7), the problem of plating metal splashes in the shielding net 5 (strip S side) entering the furnace is also eliminated. However, in the present invention in which the shielding net 5 is installed at the mounting position of the on-bath support roll 7 as shown in FIG. 1, the effect of shielding the plating metal splash 4b rising together with the airflow 3b from entering the furnace is effective. Run short.

  Therefore, in the present invention, the current plate 6 is provided as shown in FIG. 1 as means for reducing metal splashes that are greatly increased by the rising air flow 3b. By arranging the current plate 6 below the wiping nozzle 2 and above the plating metal bath 1, the rising airflow 3b is guided in the direction opposite to the strip S and the furnace. As a result, the plated metal splash 4b that rises together with the air flow 3b is also guided in the direction opposite to the strip S, so that the plated metal splash 4b enters the furnace through the space provided above the wiping nozzle 2. In addition, the phenomenon of adhering to the surface of the strip S is effectively suppressed.

  As shown in FIG. 1, the rectifying plate 6 is preferably installed such that the angle θ formed with the bath surface 1 a of the plating metal bath 1 is not less than 0 ° and not more than 60 °. That is, in FIG. 1, the plate surface of the rectifying plate 6 is arranged so as to be perpendicular to the paper surface (the surface perpendicular to the strip S surface and the bath surface 1 a), and on the side where the strip S of the rectifying plate 6 is arranged. In the case where the line passing through the end 6a and parallel to the width direction of the strip S is the center line of the elevation angle, the elevation angle is preferably set to 0 ° or more and 60 ° or less. When the angle θ formed by the rectifying plate 6 and the bath surface 1a of the plated metal bath 1 is less than 0 °, the metal splashes may return to the strip S side. On the other hand, if the angle θ formed by the current plate 6 and the bath surface 1a of the plating metal bath 1 exceeds 60 °, the effect of inducing the rising air flow 3b in the direction opposite to the strip S becomes insufficient, and the plating metal There is a possibility that the phenomenon that the splash 4b passes through the space provided above the wiping nozzle 2 and adheres to the surface of the strip S cannot be sufficiently suppressed. For the above reasons, the angle θ formed by the current plate 6 and the bath surface 1a of the plating metal bath 1 is preferably set to 0 ° or more and 60 ° or less. More preferably, it is 20 ° or more and 60 ° or less.

  The dimensions of the rectifying plate 6 are such that the end 6a on the side where the strip S is arranged in the end 6a, 6b in the horizontal direction is the same as the end 2a on the side where the gas ejection hole is not formed in the wiping nozzle 2. It is preferable to install so as to contact. Further, the rectifying plate 6 is installed so that the end 6b on the side opposite to the side on which the strip S is arranged reaches the upper side of the end 1b of the plating metal bath 1 among the horizontal ends 6a, 6b. It is preferable to do. In the case where a snout (not shown) is provided, it is preferable that the end 6b of the current plate 6 is installed so as to reach the position of the snout. Further, the dimensions of the current plate 6 are preferably set so that the length in the direction parallel to the width direction of the strip S is equal to or longer than the width of the strip S.

  As described above, according to the present invention, by providing the rectifying plate 6 below the wiping nozzle 2 and above the plating metal bath 1, the plating metal splashes 4b rising along with the air flow 3b are stripped through the wiping nozzle 2 above. The phenomenon of adhering to the S surface can be effectively suppressed. By using the shielding net 5 together with the current plate 6, it is possible to solve various problems associated with the prior art using the metal plate 20 having a complete shielding structure as shown in FIG.

  In the present invention, the type of strip that is a material to be plated is not particularly limited, and the type of molten metal plating is not particularly limited. Furthermore, in the present invention, an alloying furnace may be provided on the downstream side of the molten metal plating apparatus, and the alloying process may be performed on the strip after the molten metal plating process.

  In the present invention including the rectifying plate 6, the plating metal splash 4a that diverges upward at the time of wiping reaches the lower part 5b of the shielding net 5, and then passes through the mesh of the lower part 5b of the shielding net 5. May fall on 6 and accumulate. Here, in the prior art shown in FIG. 3, there is a problem in that the plating metal droplets deposited on the metal plate 20 re-spray in an air flow that changes depending on the operating conditions of the metal plating line and adhere to the surface of the strip S after wiping. It was seen. However, in the present invention, there is almost no problem that the plating metal droplets deposited on the rectifying plate 6 come again and adhere to the surface of the strip S after wiping. This is because, in the prior art shown in FIG. 3, there is nothing that blocks the plated metal splash deposited on the metal plate 20 and the surface of the strip S. In the present invention, as shown in FIG. The wiping nozzle 2 and the shielding net 5 are disposed between the plated metal splash 4a deposited on the surface of the strip S, and the surface of the strip S after the wiping of the plated metal splash 4a, which has come back again, is present. It is for preventing adhering to.

(Example of the present invention)
The steel strip (steel type: SPCC, thickness: 0.7 mm cold-rolled steel strip) was plated using the molten metal plating apparatus of the present invention shown in FIG. In FIG. 1, the details of the shielding net 5 and the current plate 6 are as follows.
Material of shielding net 5: Stainless steel Mesh size of shielding net 5: 1.5mm (upper part), 3.0mm (lower 20mm position)
Dimension of shielding net 5 in width direction: width of steel strip + 200mm
Angle θ between current plate 6 and bath surface 1a: 30 °
Size of current plate 6: (steel strip width + 200mm) x 700mm
Further, the upper end 5a of the shielding net 5 is brought into contact with the bath support roll support 7a and the lower end 5b of the shielding net 5 is brought into contact with the wiping nozzle 2, so that the wiping nozzle 2 and the bath support roll support 7a are connected to the shielding net 5 Connected through. Further, the end 6 a of the rectifying plate 6 was brought into contact with the end 2 b of the wiping nozzle 2.
The plating conditions are as follows.
Plating bath composition: Hot-dip zinc (0.14% Al)
Plating bath temperature: 460-470 ° C
Steel strip transport speed: 150mpm
Wiping conditions: Nozzle gap 0.7mm,
Header pressure 0.8kg / cm ² G,
Nozzle-steel distance 4mm

(Comparative example)
The following filter 40 and metal plate 20 were arranged so as to have the same configuration as the conventional molten metal plating apparatus shown in FIG. 3, and the other conditions were evaluated in the same manner as in the example.
Filter 40 material: Stainless steel Filter 40 dimensions: (Strip width + 200mm) x 700mm
Filter 40 mesh size: 1.5mm
Metal plate 20 material: Stainless steel Metal plate 20 dimensions: Steel strip width + 200mm

  About the hot-dip metal-plated steel strip obtained by each of this invention example and the comparative example, the failure rate (ratio of inferior goods) was calculated | required. When plating metal splashes adhere to the surface of the molten metal-plated steel strip, color unevenness occurs as the amount of adhesion increases. Therefore, the surface of the obtained molten metal-plated steel strip was observed, and the deterioration rate was determined by confirming the state of occurrence of color unevenness.

  In the comparative example using the conventional molten metal plating apparatus shown in FIG. 3, the crash rate was 0.5%, whereas in the present invention example using the molten metal plating apparatus shown in FIG. 1, the crash rate was 0.2%. It was confirmed that it was reduced.

1 ・ ・ ・ Plating metal bath
1a ・ ・ ・ Bath surface
2 ・ ・ ・ Wiping nozzle
3 ・ ・ ・ Gas
3a, 3b ・ ・ ・ Gas flow
4a, 4b ・ ・ ・ plated metal splash
5 ・ ・ ・ Shielding net
6 ・ ・ ・ Current plate
7 ・ ・ ・ Bath support roll
7a ... Bath support roll support
S ・ ・ ・ Strip
10 ・ ・ ・ Alloying furnace
20 ・ ・ ・ Metal plate
30 ・ ・ ・ Snout
40 ・ ・ ・ Filter

Claims (4)

  The strip is continuously drawn out from the plating metal bath, and excess plating metal adhering to the strip surface is squeezed out by a gas sprayed from the wiping nozzle toward the strip surface to adjust the amount of plating metal adhesion. In a molten metal plating method using a gas wiping method, a bath support roll for vertically supporting the strip is disposed above the wiping nozzle, and along the strip surface upward from a position where the wiping nozzle is disposed. A shielding net is provided up to the position where the support roll on the bath is disposed, and a rectifying plate is provided between the wiping nozzle and the bath surface of the plating metal bath, whereby plating metal splashes on the strip surface during molten metal plating. A molten metal plating method characterized by preventing adhesion.   2. The molten metal plating method according to claim 1, wherein an angle formed between the rectifying plate and the bath surface of the plated metal bath is set to 0 ° or more and 60 ° or less.   A plating metal bath and wiping for adjusting the amount of plating metal adhesion by squeezing off excess plating metal adhering to the strip surface by injecting gas toward the surface of the strip drawn continuously from the plating metal bath A molten metal plating apparatus comprising: a nozzle; and a bath-supporting roll that vertically supports a strip that is disposed above the wiping nozzle and that is continuously drawn out from the plating metal bath, wherein the wiping nozzle is disposed. A shielding net disposed upward from the position along the strip surface to the position where the above-mentioned support roll on the bath is disposed, and a current plate disposed below the wiping nozzle and above the plated metal bath. A molten gold characterized by preventing plating metal droplets from adhering to the strip surface during molten metal plating Plating apparatus.   The molten metal plating apparatus according to claim 3, wherein an angle formed between the current plate and the bath surface of the plating metal bath is 0 ° or more and 60 ° or less.

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