JPH11172400A - Continuous hot dip coating device and continuous hot dip coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous hot dip coating device capable of improving the quality of plating layers and obtaining a uniform plating thickness and a continuous hot dip coating method. SOLUTION: A steel strip 10 is held between a pair of rolls 30A, 30B. A molten metal bath is formed between these rolls and the steel strip 10 and the surfaces of the steel strip 10 moving upward are continuously subjected to hot dip coating. Alternating magnetic field generating coils 32A, 32B are arranged in the rolls 30A, 30B to generate the force to suppress the force to lift the molten metal by the steel strip 10, by which the plating thickness is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous hot metal plating apparatus and a continuous hot metal plating method for continuously plating a running steel strip.

[0002]

2. Description of the Related Art Conventionally, when a steel strip is continuously subjected to molten metal plating, a steel strip heated and annealed in an annealing furnace is guided through a snout in a non-oxidizing atmosphere into a molten metal pot. The direction is changed by a sink roll immersed in the bath, pulled up and plated. The plating thickness control of the steel strip is performed by ejecting gas from a nozzle to the steel strip surface when the steel strip is pulled up above the molten metal pot, and trying to obtain a predetermined plating thickness by blowing away the excessively adhered molten metal. Gas wiping methods have been used.

[0003] However, in the gas wiping method, when thinning and high-speed plating are to be performed, the method of controlling the plating thickness relies solely on gas injection, so that it is absolutely necessary to increase the injection gas pressure and speed. . For this reason, the jet gas resonates in the nozzle slit portion, intense noise is generated and the working environment is remarkably deteriorated, and molten metal on the surface of the steel strip is scattered, so that clogging of the nozzle is induced, and the jet gas is injected. And it is difficult to obtain a uniform plating thickness.

On the other hand, for example, Japanese Patent Application Laid-Open No. 61-16 / 1986
As described in JP-A-3256 and JP-A-49-24844, on an open molten metal pot,
There is known a method of controlling a plating thickness by providing a multilayer winding around a pair of rollers driven to rotate and generating a thrust reverse to a moving direction of a steel strip held between the rollers.

[0005]

However, even in the conventional gas wiping method, Japanese Patent Application Laid-Open No. 61-16325 discloses a method.
No. 6, JP-A-49-24844 also discloses that the steel strip is continuously introduced and drawn into a molten metal pot having an open top, so that the steel strip is In the middle of the molten metal bath and under the molten metal, iron dross and the like are convected or settled, so that the steel strip entrains these dross when passing through the molten metal bath, resulting in clean plating. There was a problem that the skin was damaged and the surface quality of the steel strip was inferior.

It is an object of the present invention to provide a continuous hot-dip metal plating apparatus and a continuous hot-dip metal plating method capable of improving the quality of a plating layer and obtaining a uniform plating thickness.

[0007]

(1) In order to achieve the above object, the present invention provides a pair of rolls for holding a steel strip,
A molten metal supply means for supplying molten metal so as to form a molten metal bath between the pair of rolls and the steel strip at an upper part of the pair of rolls, and the molten metal is lifted by the steel strip. And a plating thickness control means for generating a force for suppressing the force to be applied, wherein the surface of the steel strip is continuously coated with molten metal and its thickness is controlled. With such a configuration,
By performing plating using a molten metal in a clean molten metal bath, the quality of the plating layer is improved, and a uniform plating thickness is obtained by the plating thickness control means.

(2) In the above (1), preferably,
The plating thickness control means is an alternating magnetic field generating coil disposed inside the pair of rolls. With this configuration, the thickness of the plating can be controlled by generating a suppressing force by the magnetic field generated by the alternating magnetic field generating coil.

(3) In the above (1), preferably,
The plating thickness control means is a pair of electromagnetic rolls disposed above the pair of rolls and having an alternating magnetic field generating coil disposed therein. With this configuration, the magnetic field generated by the alternating magnetic field generating coil can generate a suppressing force to control the plating thickness.
It is possible to improve the maintainability of the roll on which the alternating magnetic field generating coil is disposed.

(4) In the above (1), preferably,
Further, a support roll for supporting the pair of rolls is provided.

(5) In the above (1), preferably,
Further, the molten metal disposed below the pair of rolls and recovering the molten metal overflowing from the molten metal bath and supplying the recovered molten metal to the molten metal supply means to circulate the molten metal is provided. A circulation means is provided. With such a configuration, by circulating the molten metal, the capacity of the molten metal can be reduced with a compact facility, and the deterioration of the quality of the plating layer due to dross can be suppressed.

(6) In the above (2) or (3), preferably, the surface layer of the roll in which the alternating magnetic field generating coil is disposed is made of ceramics. With such a configuration, the durability of the roll can be improved.

(7) In the above (1) or (4), preferably, a tray for recovering molten metal overflowing from the molten metal bath is provided below the pair of rolls or the support roll, and the pair of rolls is provided. The lower part of the roll or the support roll is immersed in the molten metal collected in the tray. With this configuration, the upper atmosphere and the lower atmosphere of the roll can be shut off.

(8) In order to achieve the above object, the present invention provides a method for supplying molten metal between a pair of rolls and the steel strip, the upper part of the pair of rolls holding a steel strip. To form a molten metal bath, and continuously apply molten metal plating to the surface of the steel strip, and generate a force that suppresses the force of lifting the molten metal by the steel strip to reduce the plating thickness. It is intended to be controlled. According to this method, the quality of the plating layer is improved by plating using the molten metal in the clean molten metal bath, and a uniform plating thickness is obtained by the suppressing force.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A continuous molten metal plating apparatus according to one embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view of a continuous molten metal plating apparatus according to one embodiment of the present invention, and FIG. 2 is a sectional view of an electromagnetic roll used in the continuous molten metal plating apparatus according to one embodiment of the present invention. 3 is a cross-sectional view of the continuous hot-dip metal plating apparatus according to one embodiment of the present invention, and FIG. 4 is a cross-sectional view of the continuous hot-dip metal plating apparatus according to one embodiment of the present invention. It is a top view.

As shown in FIG. 1, the steel strip 10 is
From 0, the steel strip 10 passes through the snout 22, and the traveling direction of the steel strip 10 is changed vertically by a deflector roll 26 arranged in the chamber 24, and the steel strip 10 travels upward from below. A hot leveler 28 for straightening the steel strip 10 is installed above the deflector roll 26.

In this embodiment, the hot leveler 2
A portion to be plated is provided in a portion where the steel strip 10 on the upper portion of the upper part 8 travels from below to above. That is, plating is not performed between the snout 22 and the deflector roll 26 and between the deflector roll 26 and the steel strip 10 as in the related art.

A portion to be plated has a pair of electromagnetic rolls 30 opposed to each other in a direction perpendicular to the traveling direction of the steel strip 10.
A and 30B are arranged. Electromagnetic rolls 30A, 30
B has alternating magnetic field generating coils 32A, 32B
And it is possible to generate an alternating magnetic field from inside the roll. The pair of electromagnetic rolls 30A and 30B are arranged so as to sandwich the steel strip 10 that moves upward from below. Further, a pair of electromagnetic rolls 30A, 30
A molten metal bath 40 is formed on the upper part of B and between the pair of electromagnetic rolls 30A, 30B and the steel strip 10.

The plating is performed only at the roll portion. Here, the roll portion is a portion of the molten metal bath 40 where the steel strip 10 and the molten metal are in contact with each other, and the vicinity of the contact portion between the pair of electromagnetic rolls 30A and 30B having the molten metal adhered to the surface and the steel strip 10. It is. Note that the electromagnetic roll 30 slightly
A and 30B also include those which are plated in contact with the steel strip 10 and the molten metal at the lower part.

By plating only at the roll portion, a conventional large-sized molten metal pot is not required. Also, there is no need to store a large amount of molten metal in a large molten metal pot,
When changing the type of the molten metal, the work can be easily and efficiently performed. The plating is not performed between the deflector roll 26 and the electromagnetic rolls 30A and 30B.

Here, referring to FIG.
The configuration of A, 30B will be described. The same reference numerals as those in FIG. 1 indicate the same parts. Electromagnetic roll 30A, 3
OB has alternating magnetic field generating coils 32A and 32B on the outer peripheral portion inside the roll. The alternating magnetic field generating coils 32A and 32B have different polarities, and generate a magnetic field in the direction from the alternating magnetic field generating coil 32A to the alternating magnetic field generating coil 32B by a current supplied from the alternating magnetic field generating power supply 38, for example. I do. An eddy current is generated on the surface of the steel strip 10 by a magnetic field orthogonal to the steel strip 10. This eddy current generates an electromagnetic force from above the steel strip 10 to below.

With such a configuration, an alternating magnetic field is generated from the inside of the roll to the molten metal bath, and
By generating a force (wiping force) that suppresses a force that attempts to lift the molten metal, the plating thickness can be controlled. By increasing the current flowing through the alternating magnetic field generating coils 32A and 32B, the suppressing force is increased, and the plating thickness can be controlled to be thin.
By reducing the current flowing through the alternating magnetic field generating coils 32A and 32B, the plating thickness can be controlled to be large.

Roll surface layer 3 of electromagnetic rolls 30A and 30B
4A and 34B are made of ceramics. When the roll surface layer is made of ceramics, the roll surface layer has corrosion resistance to molten metal. As the ceramic, for example, a boride-based ceramic or a carbide-based ceramic is used.

As shown in FIG. 1, as a method of forming the molten metal bath 40, for example, electromagnetic rolls 30A, 30B
The molten metal bath 40 can be formed by supplying a desired amount of the molten metal 44 in the molten metal circulation pot 42 through the molten metal supply pipe 48 using the supply pump 46 on the upper part of the bath. At this time, the supply site of the molten metal may be the surface of the electromagnetic rolls 30A and 30B or the surface of the steel strip 10, and it is sufficient that an appropriate amount of the molten metal bath 40 is formed.

The steel strip 10 comprises a pair of electromagnetic rolls 30A, 30
B, through the molten metal bath 40 and the steel strip 10
Since plating is performed on the substrate, a sufficiently alloyed plating layer can be obtained.

The alloying processing time is required to be approximately 0.05 seconds or more, and the required alloying processing time can be satisfied by forming the molten metal bath 40 of the present embodiment. Since the desired alloying treatment time can be satisfied, a sufficiently alloyed plating layer can be obtained.

Next, a device for collecting the molten metal overflowing from the molten metal bath 40 will be described. The molten metal that has overflowed from the molten metal bath 40 is collected by the tray 50. The saucer 50 includes a pair of electromagnetic rolls 30A, 30B.
And the deflector roll 26, and the steel strip 10
It is arranged below the pair of electromagnetic rolls 30A and 30B with a slight gap so as not to contact with the magnetic rolls 30A and 30B. Saucer 50
Is formed larger than the surface of the electromagnetic rolls 30A and 30B on the side opposite to the steel strip. The molten metal overflowing from the molten metal bath 40 forms a flow toward the surface of the electromagnetic rolls 30A, 30B on the side opposite to the steel strip via the upper surfaces of the electromagnetic rolls 30A, 30B, and is collected by the tray 50.

In the present embodiment, the electromagnetic roll 30
A, 30B via the upper surface of the electromagnetic rolls 30A, 30B
Since the molten metal flows toward the surface on the side opposite to the steel strip and is collected in the tray 50, the electromagnetic rolls 30A and 30
The formation of an oxide layer of the molten metal on the surface B is suppressed, and a clean molten metal without dross is obtained.

The lower part of the electromagnetic rolls 30A, 30B is disposed so as to be immersed in the collected molten metal 44 collected in the receiving tray 50, and the electromagnetic rolls 30A, 30B
The upper atmosphere and the lower atmosphere can be cut off.

By arranging the lower part of the electromagnetic rolls 30A and 30B so as to be immersed in the recovered molten metal 44 collected in the receiving tray 50, the molten metal 44 in the receiving tray 50 can be transferred to the electromagnetic roll 30A. , 30B is attached to the surface of the molten metal along with the rotation thereof and supplied to the molten metal bath 40, so that the molten metal bath 40 is formed even when the molten metal is supplied to the tray 50 by the molten metal supply pipe 48. be able to.

By arranging the lower part of the electromagnetic rolls 30A and 30B so as to be immersed in the recovered molten metal 44 recovered in the tray 50, the eddy current generated by the alternating magnetic field generating coil is reduced. It also occurs in the molten metal inside. Therefore, since the electromagnetic force generated over the entire width of the steel strip 10 can be made uniform, the edge effect in which the thickness of the plating increases at both ends can be eliminated, and the thickness of the plating in the width direction can be made uniform. Become like

By increasing the amount of molten metal supplied to the molten metal bath 40, the electromagnetic rolls 30A, 30
B, the thickness of the molten metal flowing toward the surface on the side opposite to the steel strip of the electromagnetic rolls 30A and 30B via the upper surface of the electromagnetic rolls 30A and 30B can be increased in the roll radial direction.
Oxide layer formation of the molten metal on the OB surface can be suppressed.

An upper side seal 52 and a lower side seal 54 are provided at both ends of the body length of the electromagnetic rolls 30A and 30B. By providing the upper side seal 52 and the lower side seal 54, the molten metal bath 40
Can be prevented from leaking from the body end portions of the electromagnetic rolls 30A and 30B, and the molten metal is collected by the tray 50.

Further, as shown in FIG.
Side molten metal trays 56 are provided at both end portions of the body length portions of 0A and 30B. Side molten metal tray 56
Is for recovering leakage of molten metal from outside the width of the steel strip 10 with the lower space between the electromagnetic rolls 30A and 30B and the steel strip 10, Leakage of molten metal from outside the width of the steel strip 10 can be prevented. The side molten metal tray 56 is provided with moving means so that the side molten metal tray 56 can be moved in accordance with a change in the width of the steel strip 10. By providing this moving means, it is possible to perform a plating operation on the steel strips 10 of various widths.

Receiving pan 50 and side molten metal receiving pan 56
A discharge port for discharging the collected molten metal is provided at the bottom of the container, and the molten metal is recovered from the discharge port to the molten metal circulation pot 42 via a molten metal recovery pipe 49. The molten metal collected in the molten metal circulation pot 42 is
The molten metal is supplied again from the molten metal circulation pot 42 to the plating section by a molten metal supply pump 46 via a molten metal supply pipe 48. The discharge port of the tray 50 and the side molten metal tray 56 does not have to be at the bottom, and may be provided at a position where discharge is possible.

As described above, the pair of electromagnetic rolls 30A and 30B sandwiching the steel strip 10 and the pair of electromagnetic rolls 30 while continuously supplying molten metal from the molten metal circulation pot 42.
The steel strip 10 is plated only at the A and 30B portions.
Below the electromagnetic rolls 30A and 30B, a tray 50 for collecting a desired molten metal and a side molten metal tray 56 are provided, and the molten metal collected in the tray 50 and the side molten metal tray 56 is supplied to the molten metal circulation pot 42 and the molten metal is poured into the molten metal circulation pot 42. Since the molten metal circulating device is configured to be fed, the molten metal is circulated, so that the capacity of the molten metal can be reduced with a compact facility and the quality of the plating layer can be prevented from deteriorating due to dross.

Further, in the present embodiment, a dross recovery device 58 which is a reduction device for purifying the molten metal is provided in the molten metal circulation device. Dross recovery device 58
Is provided between the molten metal recovery pipe 42 and a portion of the molten metal recovery pipe 49, that is, from the portion of the tray 50 or the side molten metal tray 56 that collects the molten metal. By installing a dross recovery device 58 that is a reducing device that decomposes dross such as oxidized dross in the middle of the molten metal recovery pipe 49, dross can be separated and clean molten metal can be returned to the molten metal circulation pot 42. . Further, by providing a reducing device in the molten metal supply pipe 48, the cleanliness of the supplied molten metal can be improved.

In this embodiment, a heater power supply 60 is provided, and a current is supplied to a heater 62 embedded in the pan 50 to heat the pan 50 to prevent the molten metal from hardening. ing. Also, the heater power supply 60
Are the electromagnetic rolls 30A and 30B, the upper side plate 5
2. Electric current is also supplied to the lower side plate, and the molten metal is heated to prevent adhesion.

Injection nozzles 70 for injecting non-oxidizing gas are installed on both sides in the thickness direction of the steel strip below the electromagnetic rolls 30A and 30B.
Leakage of the molten metal to the lower part of B is prevented.
Non-oxidizing gas is injected from the injection nozzle 70 to the pair of electromagnetic rolls 30.
Spraying between A, 30B and the steel strip 10 can suppress leakage of molten metal and surface oxidation of the steel strip 10 immediately before plating. When the tray 50 is provided, the injection nozzle 70 is installed so as to blow a non-oxidizing gas between the pair of electromagnetic rolls 30A, 30B and the steel strip 10 from the gap between the tray 50 and the steel strip 10. Here, Ar gas, N2 + H2 gas, N2 gas or the like is used as the non-oxidizing gas. The non-oxidizing gas is supplied from the non-oxidizing gas supply device 72.

Further, the space from the heating furnace 20 heated by the heater 20 to the electromagnetic rolls 30A and 30B via the snout 22 and the chamber 24 is made to have a non-oxidizing atmosphere. The non-oxidizing gas is supplied from the non-oxidizing gas supply device 72.

As described above, by setting the atmosphere around the steel strip to a non-oxidizing atmosphere or using a non-oxidizing gas, the surface of the steel strip 10 can be prevented from being oxidized, and a good plating surface can be obtained. it can.

Next, a rotation driving mechanism of the electromagnetic rolls 30A and 30B will be described with reference to FIGS. 3 and 4, the same reference numerals as those in FIG. 1 indicate the same parts.

The motors 80A and 80B are controlled by the motor control device 82 in terms of the rotation speed and the rotation direction. The rotational driving force of the motors 80A and 80B is transmitted to the electromagnetic rolls 30A and 30B by the spindles 84A and 84B, and rotates the electromagnetic rolls 30A and 30B. The motor control device 82 controls the rotation of the electromagnetic rolls 30A and 30B so as to synchronize with the speed of the traveling steel strip 10. Therefore, the steel strip 10 can be smoothly applied to the electromagnetic rolls 30A, 30B.
Can pass through.

The gap adjusting device 86 adjusts the gap between the electromagnetic rolls 30A and 30B, and adjusts the gap between the electromagnetic rolls 30A and 30B according to the thickness of the steel strip 10. The width adjusting device 88 adjusts the interval between the upper side seals 52, and adjusts the interval between the upper side seals 52 according to the plate width of the steel strip 10.

In the above description, the electromagnetic roll 30
Although A and 30B are arranged at the same height, the height can be changed within a range where the required molten metal bath 40 can be formed without making the heights exactly the same.

As described above, according to this embodiment, an electromagnetic force is induced in the molten metal by the alternating magnetic field generating coil by providing a roll having an alternating magnetic field generating coil inside a pair of steel sheets. By controlling the electromagnetic force so as to suppress the force for lifting the molten metal accompanying the movement of the steel strip from below to above in the molten metal bath, uniform plating thickness can be controlled. .

Further, a molten metal bath (pool) is formed in a space between the pair of rolls and the steel strip facing each other with the steel strip therebetween, and the steel strip is passed through the molten metal in the molten metal bath. Since plating is performed continuously and the molten metal flows out of the molten metal bath, the formation of an oxide layer of the molten metal on the surface of the electromagnetic roll can be suppressed, and the quality of plating can be improved.

Further, the molten metal collected in the tray is collected in a molten metal circulation pot, and the molten metal is recirculated. Since the molten metal is constantly circulated, the molten metal is circulated in the plating section. And the like are prevented from floating and remaining, plating is performed with a clean molten metal, and the quality of plating is improved.

Further, by using a molten metal bath, a conventional large molten metal pot for plating the surface of a steel strip can be eliminated, resulting in a compact facility.

Further, since a large-sized molten metal pot is not required, a large amount of molten metal is not required, and the operation of changing the type of molten metal can be performed simply and efficiently.

In addition, since the alloying time for contact between the molten metal and the steel strip can be sufficiently ensured, the surface quality of the plating layer can be improved.

Further, since the surface of the electromagnetic roll is covered with ceramics, the durability of the electromagnetic roll can be improved.

Next, a continuous hot metal plating apparatus according to a second embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to a second embodiment of the present invention. The same reference numerals as those in FIG.
The same parts are shown.

In the present embodiment, a pair of metallic plating rolls 90A, 90B opposed to the direction in which the steel strip 10 travels is disposed in the portion to be plated. Electromagnetic rolls 30A and 30B are arranged above 90B. Plating roll 90
A molten metal bath 40 is formed between A, 90B and the steel strip 10, and plating is performed only at the roll portion.
The thickness of the plating applied to the steel strip 10 is the same as that of the electromagnetic roll 30.
A, 30B.

As shown, the steel strip 10 is
The steel strip 10 passes through the snout 22 from above, and the traveling direction of the steel strip 10 is changed in the vertical direction by the deflector roll 26 arranged in the chamber 24, and the steel strip 10 runs upward from below.
A molten metal bath 40 is formed between the plating rolls 90A and 90B and the steel strip 10, and plating is performed only in the roll portion. By plating only in the roll portion, a conventional large-sized molten metal pot becomes unnecessary. Further, there is no need to accumulate a large amount of molten metal in a large-sized molten metal pot, and it is possible to easily and efficiently work when changing the type of molten metal.

On the upper portions of the plating rolls 90A and 90B,
A pair of electromagnetic rolls 30 </ b> A and 30 </ b> B facing in the direction perpendicular to the traveling direction of the steel strip 10 are arranged. The electromagnetic rolls 30A and 30B have alternating magnetic field generating coils 32A and 32B inside the rolls, generate an alternating magnetic field from inside the rolls, and generate an electromagnetic force from above to below the steel strip 10 to generate a steel strip. The plating on the surface of No. 10 is scraped off to control the plating thickness. The roll surface layers of the electromagnetic rolls 30A and 30B are made of ceramics as described with reference to FIG.

Since the electromagnetic rolls 30A and 30B have the alternating magnetic field generating coils 32A and 32B, the
Although the frequency of maintenance and inspection is higher than that of A and 90B, the maintenance and inspection are facilitated and the maintainability is improved because it is provided above the rolls 90A and 90B of the plating section. Also,
The electromagnetic rolls 30A and 30B are different from the example shown in FIG.
Compared to the example shown in, the contact with the molten metal is reduced,
The durability is improved.

The molten metal 44 in the molten metal circulation pot 42
Is supplied to the upper portions of the rolls 90A and 90B via the molten metal supply pipe 48 by the supply pump 46, and the molten metal bath 40 is formed. The molten metal overflowing from the molten metal bath 40 is collected by the pan 50 and the side molten metal pan shown in FIG.
The formation of an oxide layer of the molten metal on the 0B surface is suppressed, and a clean molten metal without dross is obtained. Further, an upper side seal and a lower side seal as shown in FIG. 1 are also provided.
Roll 9 is applied to the recovered molten metal 44 recovered in the pan 50.
The lower portions of the rolls 90A and 90B are arranged so as to be immersed, so that the upper atmosphere and the lower atmosphere of the rolls 90A and 90B can be shut off.

The recovered molten metal is recovered to the molten metal circulation pot 42 via a molten metal recovery pipe 49. The molten metal collected in the molten metal circulation pot 42 is
The molten metal is supplied again from the molten metal circulation pot 42 to the plating section by a molten metal supply pump 46 via a molten metal supply pipe 48. Further, by installing a dross recovery device 58 which is a reducing device for decomposing dross such as oxidized dross in the middle of the molten metal recovery pipe 49, the dross is separated and the clean molten metal is returned to the molten metal circulation pot 42. Can be.

The tray 50, the electromagnetic rolls 30A, 3
OB, the upper side plate and the lower side plate are heated as shown in FIG. A non-oxidizing gas is injected from the injection nozzle 70 to the pair of rolls 90A and 90B and the steel strip 10.
By spraying between them, leakage of molten metal and surface oxidation of the steel strip 10 immediately before plating can be suppressed. Further, from the heating furnace 20 heated by the heater 20 via the snout 22 and the chamber 24,
The space up to 0A and 30B is a non-oxidizing atmosphere. As described above, by setting the atmosphere around the steel strip to a non-oxidizing atmosphere or using a non-oxidizing gas, the steel strip 10
Can be prevented from oxidizing, and a good plating surface can be obtained.

The electromagnetic rolls 30A, 3A in this embodiment
A mechanism similar to that described with reference to FIGS. 3 and 4 is used as the rotation drive mechanism of the rolls 0B and the rolls 90A and 90B.

As described above, according to the present embodiment, the electromagnetic force is induced in the molten metal by the alternating magnetic field generating coil by providing the roll having the alternating magnetic field generating coil inside the pair of steel sheets. By controlling the electromagnetic force so as to suppress the force for lifting the molten metal accompanying the movement of the steel strip from below to above in the molten metal bath, uniform plating thickness can be controlled. .

Further, a molten metal bath (pool) is formed in a space between the pair of rolls and the steel strip facing each other with the steel strip therebetween, and the steel strip is passed through the molten metal in the bath so that the surface of the steel strip is formed. Since plating is performed continuously and the molten metal flows out of the molten metal bath, the formation of an oxide layer of the molten metal on the surface of the electromagnetic roll can be suppressed, and the quality of plating can be improved.

Next, a continuous hot metal plating apparatus according to a third embodiment of the present invention will be described with reference to FIG.
FIG. 6 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to a third embodiment of the present invention. The same reference numerals as those in FIG.
The same parts are shown.

In this embodiment, in addition to the configuration shown in FIG. 1, electromagnetic rolls 35A and 35B are further disposed above the electromagnetic rolls 30A and 30B. The configuration of the electromagnetic rolls 35A and 35B is similar to that of the electromagnetic rolls 30A and 30A.
The same configuration as that of B is used. Other configurations and operations are the same as those described with reference to FIGS.

The molten metal bath 40 includes the electromagnetic rolls 30A,
It is formed between 30B and the steel strip 10. The plating is performed only on the roll portion and the alternating magnetic field generating coil 32
A, 32B generates an electromagnetic force from above to below the steel strip 10 and generates a force that suppresses the force of lifting the molten metal by the steel strip 10, thereby increasing the plating thickness. Control can be performed. Further, the plating thickness control is similarly performed by the electromagnetic rolls 35A, 35B disposed above the electromagnetic rolls 30A, 30B.

In particular, when thin plating or high-speed processing is performed, the one-stage electromagnetic rolls 30A, 30A as shown in FIG.
In the case of B, if it is not possible to achieve a sufficiently thin plating or high speed,
Two-stage electromagnetic rolls 30A and 30B as in the present embodiment;
With the configuration of 35A and 35B, the performance of thin plating and high speed can be improved. Further, when one of the electromagnetic roll pairs fails, the plating thickness can be controlled by the remaining electromagnetic roll pairs.

As described above, according to the present embodiment, an electromagnetic force is induced in the molten metal by the alternating magnetic field generating coil by providing the roll having the alternating magnetic field generating coil inside the pair of steel sheets. By controlling the electromagnetic force so as to suppress the force for lifting the molten metal accompanying the movement of the steel strip from below to above in the molten metal bath, uniform plating thickness can be controlled. . In addition, the performance of thinning and high-speed plating is improved.

Further, a molten metal bath (pool) is formed in a space between the pair of rolls and the steel strip opposed to each other with the steel strip therebetween, and the steel strip is passed through the molten metal in the molten metal bath. Since plating is performed continuously and the molten metal flows out of the molten metal bath, the formation of an oxide layer of the molten metal on the surface of the electromagnetic roll can be suppressed, and the quality of plating can be improved.

Next, a continuous hot metal plating apparatus according to a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to a fourth embodiment of the present invention. The same reference numerals as those in FIG.
The same parts are shown.

In this embodiment, in addition to the configuration shown in FIG. 1, there are provided support rolls 95A and 95B for supporting the electromagnetic rolls 30A and 30B. Other configurations are the same as those of the embodiment shown in FIG.

The support rolls 95A and 95B support the electromagnetic rolls 30A and 30B, respectively.
A, 30B are arranged slightly lower than the height. Further, the electromagnetic rolls 30A and 30B are arranged so as not to be immersed in the molten metal in the saucer 50, and the support rolls 95A and 95B are provided.
B is arranged so that a part of the lower part is immersed in the molten metal in the saucer 50. With this arrangement, the support rolls 95A and 95B and the electromagnetic roll 30
The upper atmosphere and the lower atmosphere of A and 30B can be shut off.

The tray 50 is arranged with a slight gap so as not to contact the steel strip 10. The tray 50 is arranged so as to be larger than the side of the support rolls 95A and 95B opposite to the steel strip, and the molten metal flowing down from the surfaces of the support rolls 95A and 95B is collected.

The molten metal in the molten metal circulation pot 42 is
Using the supply pump 46, the molten metal supply pipes 48, 4
The desired amount is supplied to the tray 50 via 8A. The support roll 95A rotates in the direction of arrow R1A, and the support roll 95B rotates in the direction of arrow R1B. Since the support rolls 95A and 95B are partially immersed in the molten metal 44 in the receiving tray 50, the support rolls 95A and 95B supply the molten metal attached to the surface to the upper molten metal reservoirs 40A and 40B. The electromagnetic rolls 30A and 30B are in the opposite directions (arrows R2A and R2) to the support rolls 95A and 95B, respectively.
(B direction) to supply the molten metal in the molten metal pools 40 </ b> A and 40 </ b> B to the molten metal bath 40.

The surfaces of the support rolls 95A and 95B are
Like the electromagnetic rolls 30A and 30B, they are formed of ceramics. As the ceramic, a boride-based ceramic or a carbide-based ceramic is used.

By using the support rolls 95A and 95B, the molten metal can be supplied to the molten metal reservoirs 40A and 40B and supplied to the outer peripheral surfaces of the electromagnetic rolls 30A and 30B. In addition, the lower portion of the support rolls 95A and 95B supporting the electromagnetic rolls 30A and 30B
The upper atmosphere and the lower atmosphere can be shut off by immersing in the molten metal in the atmosphere of zero. Further, by adjusting the gap G between the support roll 95A and the electromagnetic roll 30A and the gap between the support roll 95B and the electromagnetic roll 30B, the thickness of the molten metal adhering to the surfaces of the electromagnetic rolls 30A and 30B is changed. It is also possible to control the plating thickness to be applied. As described above, the thickness of the plating applied to the steel strip 10 is controlled by the electromagnetic force generated by the magnetic field generated by the alternating magnetic field generating coils in the electromagnetic rolls 30A and 30B from above to below the steel strip 10. It is mainly controlled by force, and adjustment by the gap between the support rolls 95A, 95B and the electromagnetic rolls 30A, 30B is auxiliary.

As described above, according to the present embodiment, the electromagnetic force is induced in the molten metal by the alternating magnetic field generating coil by providing the roll having the alternating magnetic field generating coil inside a pair of the steel strips. By controlling the electromagnetic force so as to suppress the force for lifting the molten metal accompanying the movement of the steel strip from below to above in the molten metal bath, uniform plating thickness can be controlled. .

Further, a molten metal bath (pool) is formed in a space between the pair of rolls and the steel strip opposed to each other with the steel strip therebetween, and the steel strip is passed through the molten metal in the bath so that the surface of the steel strip is formed. Since plating is performed continuously and the molten metal flows out of the molten metal bath, the formation of an oxide layer of the molten metal on the surface of the electromagnetic roll can be suppressed, and the quality of plating can be improved.

Next, a continuous hot metal plating apparatus according to a fifth embodiment of the present invention will be described with reference to FIG.
FIG. 8 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to a fifth embodiment of the present invention. 1 and 5 indicate the same parts.

In this embodiment, in addition to the structure shown in FIG. 5, there are provided support rolls 95A and 95B for supporting the plating rolls 90A and 90B. Other configurations are the same as those of the embodiment shown in FIG.

The support rolls 95A and 95B support the plating rolls 90A and 90B, respectively, and are arranged slightly lower than the height of the plating rolls 90A and 90B. The plating rolls 90A and 90B are arranged so as not to be immersed in the molten metal in the tray 50,
A and 95B are arranged so that a part of the lower part is immersed in the molten metal in the saucer 50. With this arrangement, the upper atmosphere and the lower atmosphere of the support rolls 95A and 95B and the plating rolls 90A and 90B can be shut off.

The receiving tray 50 is arranged with a slight gap so as not to contact the steel strip 10. The tray 50 is arranged so as to be larger than the side of the support rolls 95A and 95B opposite to the steel strip, and the molten metal flowing down from the surfaces of the support rolls 95A and 95B is collected.

The molten metal in the molten metal circulation pot 42 is
Using the supply pump 46, the molten metal supply pipes 48, 4
The desired amount is supplied to the tray 50 via 8A. Since the support rolls 95A and 95B are partially immersed in the molten metal 44 in the receiving tray 50, they rotate to supply the molten metal attached to the surface to the upper molten metal pools 40A and 40B. Plating roll 90A, 9
OB rotates in the direction opposite to the support rolls 95A and 95B, and supplies the molten metal in the molten metal pools 40A and 40B to the molten metal bath 40.

On the upper portions of the plating rolls 90A and 90B,
A pair of electromagnetic rolls 30 </ b> A and 30 </ b> B facing in the direction perpendicular to the traveling direction of the steel strip 10 are arranged. The electromagnetic rolls 30 </ b> A and 30 </ b> B generate an alternating magnetic field by an alternating magnetic field generating coil inside the rolls, thereby generating an electromagnetic force from above to below the steel strip 10, scraping off the plating on the surface of the steel strip 10, and increasing the plating thickness. Control.

As described above, according to this embodiment, an electromagnetic force is induced in the molten metal by the alternating magnetic field generating coil by providing a roll having an alternating magnetic field generating coil inside a pair of steel strips. By controlling the electromagnetic force so as to suppress the force for lifting the molten metal accompanying the movement of the steel strip from below to above in the molten metal bath, uniform plating thickness can be controlled. . Moreover, since the electromagnetic roll is not in contact with the molten metal bath, the maintainability of the electromagnetic roll is improved, and the durability is also improved.

Further, a molten metal bath (pool) is formed in a space between the pair of rolls and the steel strip facing each other with the steel strip therebetween, and the steel strip is passed through the molten metal in the bath so that the surface of the steel strip is formed. Since plating is performed continuously and the molten metal flows out of the molten metal bath, the formation of an oxide layer of the molten metal on the surface of the electromagnetic roll can be suppressed, and the quality of plating can be improved.

Next, a continuous hot metal plating apparatus according to a sixth embodiment of the present invention will be described with reference to FIG.
FIG. 9 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to a sixth embodiment of the present invention. 1 and 6 denote the same parts.

In this embodiment, in addition to the configuration shown in FIG. 6, there are provided support rolls 95A and 95B for supporting the electromagnetic rolls 30A and 30B. Other configurations are the same as those of the embodiment shown in FIG.

The support rolls 95A and 95B support the electromagnetic rolls 30A and 30B, respectively.
A, 30B are arranged slightly lower than the height. Further, the electromagnetic rolls 30A and 30B are arranged so as not to be immersed in the molten metal in the saucer 50, and the support rolls 95A and 95B are provided.
B is arranged so that a part of the lower part is immersed in the molten metal in the saucer 50. With this arrangement, the support rolls 95A and 95B and the electromagnetic roll 30
The upper atmosphere and the lower atmosphere of A and 30B can be shut off.

The tray 50 is arranged with a slight gap so as not to contact the steel strip 10. The tray 50 is arranged so as to be larger than the side of the support rolls 95A and 95B opposite to the steel strip, and the molten metal flowing down from the surfaces of the support rolls 95A and 95B is collected.

The molten metal in the molten metal circulation pot 42 is
Using the supply pump 46, the molten metal supply pipes 48, 4
The desired amount is supplied to the tray 50 via 8A. Since the support rolls 95A and 95B are partially immersed in the molten metal 44 in the receiving tray 50, they rotate to supply the molten metal attached to the surface to the upper molten metal pools 40A and 40B. Electromagnetic rolls 30A, 30
B rotates in a direction opposite to the support rolls 95A and 95B, and supplies the molten metal in the molten metal pools 40A and 40B to the molten metal bath 40.

The molten metal bath 40 includes the electromagnetic rolls 30A,
It is formed between 30B and the steel strip 10. The plating is performed only on the roll portion and the alternating magnetic field generating coil 32
A, 32B generates an electromagnetic force from above to below the steel strip 10 and generates a force that suppresses the force of lifting the molten metal by the steel strip 10, thereby increasing the plating thickness. Control can be performed. Further, the plating thickness control is similarly performed by the electromagnetic rolls 35A, 35B disposed above the electromagnetic rolls 30A, 30B. In particular, when performing thin plating or increasing the speed, the two-stage electromagnetic rolls 30A, 3A
0B; 35A and 35B can improve the performance of thin plating and high speed. Further, when one of the electromagnetic roll pairs fails, the plating thickness can be controlled by the remaining electromagnetic roll pairs.

As described above, according to the present embodiment, the electromagnetic force is induced in the molten metal by the alternating magnetic field generating coil by providing the roll having the alternating magnetic field generating coil inside the pair of steel sheets. By controlling the electromagnetic force so as to suppress the force for lifting the molten metal accompanying the movement of the steel strip from below to above in the molten metal bath, uniform plating thickness can be controlled. . In addition, the performance of thinning and high-speed plating is improved.

Further, a molten metal bath (pool) is formed in a space between the pair of rolls and the steel strip facing each other with the steel strip interposed therebetween, and the steel strip is passed through the molten metal in the bath. Since plating is performed continuously and the molten metal flows out of the molten metal bath, the formation of an oxide layer of the molten metal on the surface of the electromagnetic roll can be suppressed, and the quality of plating can be improved.

[0095]

According to the present invention, the quality of the plating layer is improved by cleaning the molten metal in the plating portion, and a uniform plating thickness can be obtained by using the electromagnetic coil.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of an electromagnetic roll used in the continuous hot-dip metal plating apparatus according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view taken along the line AA of FIG. 1, and is a cross-sectional view of the continuous hot-dip metal plating apparatus according to one embodiment of the present invention.

FIG. 4 is a top view of a continuous hot-dip metal plating apparatus according to an embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to a second embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to a third embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to a fourth embodiment of the present invention.

FIG. 8 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to a fifth embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of a continuous hot-dip metal plating apparatus according to a sixth embodiment of the present invention.

[Description of Signs] 10 steel strip 20 heating furnace 22 snout 24 chamber 26 deflector roll 28 hot leveler 30A, 30B, 35A, 35B electromagnetic roll 32A, 32B alternating magnetic field generating coils 34A, 34B ceramic Reference numeral 38: power supply for the alternating magnetic field generator 40 ... molten metal bath 42 ... molten metal circulation pot 44 ... recovered molten metal 46 ... molten metal supply pump 48 ... molten metal supply pipe 49 ... molten metal recovery pipe 50 ... molten metal tray 52 upper side plate 54 lower side plate 56 side molten metal tray 58 dross recovery unit 60 heater power supply 70 injection nozzle 80A, 80B motor 82 motor controller 84A, 84B spindle 86 gap between rolls Adjusting device 88 ... Width adjusting device 90A, 90 ... plated roll 95A, 95B ... support roll

Claims (8)

[Claims] 1. A pair of rolls for sandwiching a steel strip, and a molten metal being supplied so as to form a molten metal bath above the pair of rolls and between the pair of rolls and the steel strip. Molten metal supply means, and a plating thickness control means for generating a force for suppressing a force for lifting the molten metal by the steel strip, and continuously applying molten metal plating to the surface of the steel strip A continuous hot-dip metal plating system that controls the thickness of the metal. 2. The continuous hot-dip metal plating apparatus according to claim 1, wherein said plating thickness control means is an alternating magnetic field generating coil disposed inside said pair of rolls. . 3. A continuous molten metal plating apparatus according to claim 1, wherein said plating thickness control means is a pair of electromagnetic rolls disposed above said pair of rolls and having an alternating magnetic field generating coil disposed therein. A continuous hot-dip metal plating apparatus, characterized in that: 4. The continuous hot metal plating apparatus according to claim 1, further comprising a support roll for supporting each of said pair of rolls. 5. The continuous molten metal plating apparatus according to claim 1, further comprising: a molten metal that is disposed below the pair of rolls and that overflows from the molten metal bath. And a molten metal circulating means for circulating the molten metal by supplying the molten metal to the molten metal supply means. 6. A continuous hot-dip metal plating apparatus according to claim 2, wherein a surface layer of the roll in which the alternating magnetic field generating coil is disposed is made of ceramics. Continuous hot metal plating equipment. 7. The continuous hot-dip metal plating apparatus according to claim 1, wherein a tray for collecting the molten metal overflowing from the molten metal bath below the pair of rolls or the support roll. A continuous hot-dip metal plating apparatus, comprising: immersing a lower portion of the pair of rolls or the support roll in molten metal collected in the tray. 8. A molten metal bath is formed by supplying a molten metal between the pair of rolls and the steel strip at an upper part of a pair of rolls for holding the steel strip. A continuous hot-dip metal plating method, wherein a hot-dip metal plating is continuously performed on a surface and a plating thickness is controlled by generating a force for suppressing a force for lifting the molten metal by the steel strip.