JPH01272771A - Method for continuously plating metallic sheet - Google Patents

Abstract

PURPOSE:To form a plating layer having excellent surface properties in the good yield of a plating metal by heating a traveling band steel to a temp. higher than the m.p. of the plating metal, and bringing a plating metallic material into contact with the surface of the band steel at the time of plating the band steel surface with molten metal. CONSTITUTION:When the surface of a band steel 1 is plated with molten metal of Zn, a Zn alloy, etc., the band steel 1 is preheated to a temp. higher than the m.p. of the plating metal and traveled in the direction as shown by the arrow. The plating metal material 2 heated by a preheater 5 is pressed on the surface of the continuously traveling band steel 1, and the plating metal 2 on the contact surface is melted by the heat of the band steel 1 to form a molten layer 3, and a plating film 4 is formed on the band steel 1 with the molten layer 3. The thickness of the plating layer 4 is uniformized, as required, by a surface regulator 6 such as an ultrasonic-vibration trowel. The plating metal is not wasted as dross, and a plating layer having excellent surface properties can be continuously formed in high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for continuously plating the surface of a metal plate without using a molten metal bath.

[Conventional technology]

Conventionally, as a method of forming a plating film on the surface of a copper strip,
Hot-dip plating is a widely used method in which a steel strip is immersed in pre-molten plated metal.

In continuous hot-dip galvanizing, which is a typical example of this type of plating method, the copper strip is heat-treated and surface-cleaned in a pre-treatment furnace, and then immersed in a hot-dip zinc bath to form a plating film.
The steel strip pulled out from the bath is subjected to plating coating amount adjustment by gas throttling and surface conditioning such as galvanealing.

The hot-dip plated steel sheet thus obtained has a relatively beautiful surface and excellent corrosion resistance, so it is widely used in practical applications.

[Problem to be solved by the invention]

However, conventional hot dip galvanizing methods have various problems associated with the use of plating baths. Particularly recently, plated steel strips are required to have a more uniform, smooth, and beautiful surface than ever before, mainly for use in home appliances, automobile exterior panels, etc. There is also a high demand for new products such as, and as a result, problems with the quality of plating MS by conventional hot-dip plating methods and the plating process itself have become apparent. Some of such problems are discussed below.

1) Fe from the surface of the steel strip is eluted during the plating bath, and so-called dross is often generated due to the oxidation of the plating metal, and this must be pumped up and removed. A loss of plated metal occurs.

2) Impurities are likely to be mixed into the plating bath, such as dross being generated in the plating bath or debris from the bricks that make up the pot being mixed into the bath, and these impurities adhere to the steel strip and deteriorate its appearance.

3) Since the components of the plating metal ingot put into the bath are different from the trace elements in the components that adhere to the steel strip and the components that are discharged outside the bath as by-products such as dross, the necessary elements are contained as per the target. For plating bath ingredients! It is difficult to control the 11-degree order.

As a result, various plating defects occur, such as poor plating adhesion and poor alloying of the galvanic material.

4) It is necessary to immerse steel mechanical parts such as rolls for threading copper strips, roll support arms, bearings, etc. in a high temperature, highly corrosive plating metal bath.

This causes problems such as erosion of these members, generation of dross accompanying this, and deterioration of the appearance of the plating surface due to erosion of the surface of the roll in the bath.

Furthermore, operation downtime is required to periodically repair or replace eroded or damaged parts of these mechanical parts, making it impossible to effectively and maximally utilize the production capacity of the equipment.

5) By using a passing roll in the plating bath, the group grooves of the roll are likely to be transferred to the plating surface, resulting in deterioration of the appearance.

6) Discharge of bottom dross that accumulates at the bottom of the tower.

Work near high temperature and large amounts of plating baths, such as removing top dross that accumulates on the bath surface, initial threading of steel strip into the bath, and care of rolls in the plating bath, must be performed by workers. It is a big burden and dangerous.

7) Pot - Since only one type of plating can be done per group,
When performing various types of dissimilar plating, it is necessary to carry out routine practice by pumping out a bath, or to prepare in advance a pot in which dissimilar plating metals are melted, and to move the pot.

8) When producing double-sided plated materials and single-sided plated materials in a single facility, it is necessary to change the plating equipment for the pot section, which requires a lot of time and effort in addition to the equipment burden. .

9) It is difficult to perform special plating such as double-sided dissimilar plating, multilayer plating, and double-sided differential thickness plating.

In contrast to such conventional hot-dip plating methods, JP-A-61-2
No. 07555, etc., a nozzle is brought close to the surface of the running steel strip, and the molten metal supplied from the molten metal tank is sucked out from the nozzle by the wet adhesive force between the molten metal and the surface of the copper strip, and is made to adhere to the steel strip. A solid plating method has been proposed.

This method applies coating technology for high-viscosity paint, etc., but the molten metal is fed from the molten metal tank to the nozzle, and the amount of plating deposited is controlled by the head pressure of the molten metal tank. Therefore, a change in the height of the bath surface in the tank results in variations in the amount of plating deposited, and this has the disadvantage of poor accuracy in the amount of plating deposited. Furthermore, in any case, since a molten metal bath corresponding to an immersion type plating bath is required, there are various problems as described above.

As described above, conventional hot-dip plating methods have various problems.

In view of these problems, the present invention has developed a new plating method that can continuously apply hot-dip plating to a metal plate without using a conventional molten metal bath and can control the coating amount with high precision. It is intended to provide a method.

[Means to solve the problem]

For this reason, the present invention involves melting a plated metal material by bringing it into contact with a moving metal plate heated to a temperature higher than the melting point of the plated metal, and continuously supplying the plated metal material to the metal plate. Accordingly, the molten plated metal is continuously deposited as a plating film on the surface of the moving metal plate.

Such a plating method can perform plating without using a molten metal bath at all, and in addition, the solid plating metal material is fed in the direction of the steel strip to be plated and melted only at the plating position on the ms plane. Since this is a method of depositing this on a steel strip, the amount of plating deposited can be controlled by the feeding speed of the solid plated metal material, thus ensuring high deposition amount accuracy.

In the present invention, the plated metal material may be preheated to ensure melting of the plated metal material. Further, in order to equalize the amount of deposited plating film formed, it is possible to perform a uniformization treatment.

The present invention will be explained in detail below.

FIG. 1 schematically shows the principle of the plating method of the present invention, in which (1) is a continuously running copper strip, and (2) is a plate-shaped plated metal material that is brought into contact with this copper strip.

The steel strip (1) is heated to a temperature equal to or higher than the melting point of the plated metal, and the plated metal material (2) is brought into contact with the copper strip (1) and continuously supplied. The plated metal material (2) is melted by heat conduction from the steel strip (1) to form a molten layer (3), and this molten layer (3) forms a plating film (
4) is formed. As plating progresses, the plated metal material (
2) is sent sequentially to the surface of the copper strip, resulting in continuous plating.

In such a plating method, when the speed of the steel f (1) is U, the supply speed of the plated metal material (2) is V, and the thickness of the plated metal material (2) in the direction of copper strip movement is W, the plating Film thickness H
is given by H=W(ヱ). Therefore, by keeping the supply speed V of the plated metal material constant, the plated film thickness H can be maintained constant.
is obtained.

Now, when performing zinc plating with a coating weight of 60 g/rrr (one side) using the method of the present invention, assuming W = 20 mm,
U=120m/win, V=0.857an/see
Plating is performed under certain conditions. In this case, the steel strip is heated to about 450°C.

In the method of the present invention, the plated metal material (2) can also be preheated to ensure melting of the plated metal material. FIG. 2 shows the implementation situation, and (5) is a preheating device for plated metal materials.

In order to obtain a stable plating film thickness using the method of the present invention, it is necessary to
(3) It is necessary to ensure a certain degree of thickness. If the sensible heat of the steel strip (1) is relatively low compared to the plating metal material used, the formation of molten N (3) will not be sufficient, making it difficult to ensure a stable film thickness, and the plating metal Solid contact between the material (2) and the copper strip (1) becomes significant, causing damage to the metal plate. Therefore, if there is a possibility that such a problem may occur, use plated metal materials (as shown in Figure 2).
2) is preheated using the preheating device (5).

This is supplied to the steel strip (1), thereby promoting melting of the plated metal material.

In addition, the plating film (4) formed as described above may have slight unevenness in coating amount due to the vibration of the steel strip. Uniform treatment can be performed using a surface conditioning device (6). As this surface conditioning device, for example, an ultrasonic vibration type device equipped with an ultrasonic vibrator (so-called ultrasonic iron) is used.
is used. This device is held by a cylinder device (not shown) having a buffer mechanism, etc., and its diaphragm is brought into light contact with the m-band surface on which the plating film is formed, and ultrasonic vibrations are applied to the plating film. , the thickness of the plating metal film is equalized.

In addition, in the above plating process, in order to prevent uneven plating adhesion due to vibration of the steel strip, as shown in Figure 4, the steel strip (1) is rolled using a pinch roll (7) on the upstream side of the contact area with the plated metal material. You can pinch by By doing this, it is possible to prevent the occurrence of uneven plating due to vibration of the copper band, and also prevent the occurrence of uneven plating due to vibration of the copper band.
Collision between 1) and the plated metal material (2) can be prevented.

The pinching position of the steel strip by the pinch rolls (7) should be as close as possible to the contact part of the plated metal material (2), and usually within 2000 no+ (
(more preferably within 500 inches).

As a means (pinch means) for preventing uneven adhesion due to vibration of the copper strip, it is possible to use not only the above-mentioned pinch roll but also an air action method, an electromagnetic force method, or other suitable means.

In addition, the plating process according to the present invention also improves the wettability of the plating,
To ensure adhesion, use a non-oxidizing atmosphere (e.g. H,
:20-25%, N, :80-75% mixed gas). Also in the method of the present invention, it is preferable that the surface of the steel strip before plating be as clean as possible.

The plating method according to the present invention can be applied to various metal or alloy plating, for example, Zn plating of steel strip,
Including A11-Zn alloy plating, C.

-Cr-Zn alloy plating (e.g. 1%Co-1%C
r-Zn alloy plating), Al1-Mg-Zn alloy plating (e.g., 5%An-0.6%Mg-Zn alloy plating), An-5i-Zn alloy plating (e.g., 55%A
l1-1.6%Si-Zn alloy plating), 5i-A polished alloy plating (e.g., 10%Si-Al1 alloy plating), Sn-Pb alloy plating (e.g., 10%Sn
-Pb alloy plating) etc.

Further, by using a plating metal material in which particles are dispersed in a metal or an alloy, a plated film in which the particles are dispersed in the film can be obtained. With conventional hot-dip plating methods, it is difficult to uniformly disperse particles in the bath.

It was not possible to uniformly disperse the particles in the coating, and for this reason, it was impossible to manufacture this type of particle-dispersed plated steel sheet. On the other hand, in the method of the present invention, the plated metal material is brought into contact with the steel strip to be plated and melted, so by using the plated metal material in which the particles are dispersed and cast, the particles are uniformly dispersed. It is possible to obtain a plating film.

The purpose of dispersing particles in a plating film is to improve the paintability, corrosion resistance, lubricity, abrasion resistance, etc. of the plating film, and the particles may be inorganic particles, organic particles, organic-inorganic composite particles, or Mixed particles of these are used. For example, Sin,.

Mouth 20it Tie, Zr0zt Cr2O3, Cr
y,, ZnCr0. , BaCr0it MgCr0
．． , BN, SiC, WC, TiN, MoS, diamond, various resins (Teflon, PEEK, polyimide amide, silicone resin, boron resin, etc.) and the like can be used. Further, by using a colored pigment as particles, a colored plated steel strip can be obtained.

Furthermore, in the present invention, multilayer plating is possible by bringing different types of plating metal materials (2) into contact with the copper strip before and after the direction of movement of the copper strip.

In addition, in Figures 1 to 3, the plating metal material (2) is supplied only to one side of the steel strip (1), but in the case of double-sided plating of the copper strip, the plating is applied to both sides of the steel strip. Metal material (2
), and it goes without saying that plating is performed on each surface. In this case, plating on both sides is
It is not necessary to do it at the same position in the line direction. Furthermore, the plating method of the present invention can be carried out by running the steel strip (1) in a direction other than horizontally, for example, by running it vertically. In the case of this vertical line, the running direction may be either up or down.

In addition, when plating both sides of the steel strip in the method of the present invention,
By arranging plated metal materials (2) having different compositions on both sides of the steel strip, double-sided dissimilar plating can be easily performed. For example, it is possible to obtain a copper strip, etc., which has an Fe-Zn alloy plating film on one side (painting surface) and a Zn plating film on the other side (bare surface), as an outer panel material for home appliances, etc. .

〔Example〕

(1) When performing Zn plating on a steel strip by the method of the present invention,
4 steel strips (thickness 1,6 m) moving at various speeds
It was heated to 50° C., and a zinc plate (plated metal material) at room temperature was brought into contact with this as shown in FIG. 1, and the change in the amount of Zn plating deposited was examined.

Figure 5 shows the results, and shows how the zinc plate absorbs heat from the steel strip and raises its temperature, and after a few seconds, melting begins, and eventually a constant amount of adhesion is achieved. In this example, the zinc plate was supplied so as to be melted to the extent that it could be melted by the steel strip.

(n) The plating conditions and the characteristics of the obtained plated steel strip when various alloy plating is applied to the copper strip by the method of the present invention are as follows.
Shown in the table.

(1) Table 2 shows the plating conditions and uses of the obtained steel strip when particle dispersion plating is applied to the steel strip by the method of the present invention.

〔Effect of the invention〕

According to the present invention described above, a plating film made of molten metal can be continuously formed on a metal plate without using a molten metal bath, and the following advantages are obtained compared to the conventional method using a plating bath. It will be done.

1) Since there is no generation of dross unlike when using a plating bath, there is no loss of plating metal other than adhesion to the steel strip.

2) Dross, impurities, etc. do not adhere to the surface, keeping the appearance beautiful.

3) Since the plating metal is directly welded, almost the same components as the plating metal material are plated, and the components in the plating film are uniform and the components can be easily controlled.

4) There is no need to use parts immersed in a bath, so there is no need to stop operations to repair or replace eroded machine parts.

5) Since there is no need to use rolls in the bath, there is no deterioration in appearance due to transfer of roll groups.

6) Discharging bottom dross and top dross, passing steel plates into the bath, cleaning the rolls in the bath, etc. are no longer necessary, and the burden on the operator is significantly reduced.

7) When performing various types of alloy plating, all you have to do is replace the plating metal material supplied to the steel strip, and there is no need for major work such as changing baths or moving pots, so various types of plating can be easily performed. It is possible.

8) By selecting and changing the arrangement, supply mode, feeding speed, etc. of the plated metal material, various forms of plating such as single-sided plating, multi-layer plating, double-sided differential thickness plating, double-sided dissimilar plating, etc. can be easily performed. I can do it.

In addition to these advantages, the method uses a method in which a solid plated metal material is fed in the direction of the steel strip to be plated, melts the coating weight on the steel strip surface, and attaches it to the steel strip. The amount is controlled by the feed rate of the solid plated metal material, thus ensuring a high degree of deposition accuracy.

[Brief explanation of the drawing]

1 to 4 are explanatory diagrams schematically showing the principle of the method of the present invention. FIG. 5 shows the change in Zn adhesion amount in Examples. In the figure, (1) is a steel strip, (2) is a plated metal material, (
3) is a molten pool, and (4) is a plating film. 4th eup 5th time t (Sec)

Claims (3)

[Claims] (1) By bringing a plated metal material into contact with a moving metal plate that is heated to a temperature higher than the melting point of the plated metal, it is melted, and by continuously supplying the plated metal material to the metal plate, A continuous plating method for metal plates, characterized by continuously depositing molten plated metal on the surface of a moving metal plate as a plating film. (2) The continuous plating method for a metal plate according to claim (1), characterized in that a preheated plated metal material is brought into contact with the metal plate. (3) The continuous plating method for a metal plate according to claim (1) or (2), characterized in that after the plating film is formed, a treatment is performed to equalize the amount of the plating film deposited.