JPH02111864A - Production of hot dip plated metal sheet - Google Patents

Abstract

PURPOSE:To facilitate the handling of a solid metal material for plating, to control coating weight with high accuracy and to made the coating weight uniform by sending and melting the solid metal material in accordance with the required amt. for plating at a position just before a feeding hole, atomizing the resulting molten metal with hot gas and adhering atomized particles to a travelling metal sheet. CONSTITUTION:A solid metal material 2 for plating in a metal material feeder 1 is successively sent toward the feeding hole 5 of the feeder 1 and is successively melted from the tip with a heating element 6 at a position just before the hole 5. The resulting molten metal A for plating is ejected from the hole 5 and hot has heated to a temp. above the m.p. of the metal material 2 is blown on the molten metal A from a gas jetting hole 7 to atomize the molten metal A. Atomized particles (a) of the molten metal A are adhered to a steel strip 3 travelling upward along the feeder 1 at a prescribed interval to form a plating film 8. Plating giving fine appearance can be carried out on the surface of the metal sheet without using a molten metal bath.

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 for forming a plating film on the surface of steel strip,
Hot-dip plating is a widely used method in which a copper strip is immersed in pre-molten plating 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 copper strip pulled out of the bath is subjected to plating deposition amount adjustment using gas aperture, 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 applications such as home appliances and automobile exterior panels. Demand for new products such as plating is also high (and as a result, problems with the quality of plated copper strips produced using conventional hot-dip plating methods and the plating process itself have become apparent. Some of these problems are described below.

1) Fe from the surface of the copper strip is eluted in 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. Loss of plated metal occurs.

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

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, it is necessary to contain the necessary elements as targeted. It is difficult to adjust and control the bath components.

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, top dross that accumulates on the bath surface, initial threading of steel strip into the bath, maintenance of rolls in the plating bath, etc. at high temperatures and in large quantities. Working near the plating bath places a heavy burden on the worker and is dangerous.

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

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
In 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 adhesion force with the surface of the molten metal 1!47 steel strip, and adheres to the copper strip. A tightening method has been proposed to allow

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. Further, 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.

The present inventors have developed a method for such conventional hot-dip plating methods.
He devised a new plating method that did not require a molten metal bath at all, and proposed this as No. 103302/1983.

In this method, a solid-phase plated metal material is continuously fed toward the surface of a copper strip through which the sheet is passed, and the tip side of the plated metal material is heated and melted using a heating melting device facing the copper strip. The copper strip is sequentially melted just before the surface, and the molten plating metal is continuously adhered to the surface of the copper strip as a plating film.

This method melts the plating metal just before plating and deposits this molten metal as the plating metal, and does not require a molten metal bath at all, so it solves the conventional problems associated with plating tower side use. Moreover, by controlling the feeding speed of the solid-phase plated metal material, there is an advantage that the amount of plating deposited can be controlled with high precision.

However, in this plating method, the amount of plating metal supplied from the nozzle is determined by the gap between the nozzle tip and the metal plate surface, so the gap between the nozzle tip and the metal plate surface is very fine and is equivalent to the thickness of the plating film. It is necessary to make it a thing. However, it is difficult to maintain a constant minute gap between the metal plate and the nozzle because it is unavoidable that the plated metal plate undergoes some degree of vibration while passing through the plate, and the plate may also be defective in shape. This may lead to troubles such as corrosion or collision between the nozzle and the plate.

In view of these problems, the present invention makes it possible to continuously apply hot-dip plating to a metal plate without using a conventional molten metal bath, and also enables highly accurate control and uniformity of the coating amount. The purpose of this paper is to provide a new plating method.

[Means to solve the problem]

For this reason, the continuous supply of solid-phase plating metal material is
The hot-dip plated metal is sequentially melted from the tip side near the metal plate to be passed through, and the hot-dip plated metal is atomized by spraying an excessively high temperature gas higher than the melting point of the plated metal material in the direction of the copper strip, The atomized hot-dip plating metal is applied as a plating film to the metal plate being passed through.

The most important feature of the present invention is that the solid-phase plating metal material is melted by the plating area weight immediately before plating, and this is then plated. Handling of plated metal and controlling the amount of coating is extremely easy compared to other methods.

Another feature of the present invention is that hot-dip plating metal is atomized by spraying hot gas at a temperature higher than its melting point onto the molten plating metal material, and this is directly attached to the metal plate surface as a plating film. This is due to the fact that it was made to
By doing so, the distance between the plating metal supply device and the metal plate to be passed can be relatively wide, and a uniform plating film can be obtained without being affected by vibrations of the plate or the like.

〔Example〕

Figure 1 shows an example in which the method of the present invention is applied to continuous plating treatment of copper strips. It is a copper strip that is plated.

The plated metal material supply bag R(1) has a guide portion (4) for guiding the solid phase (plate-shaped in this example) plated metal material (2) upward, and the guide portion has a The upper end is provided with an upwardly directed supply port (5) for discharging molten plating metal.

In this embodiment, this guide portion (4) is constituted by a cylindrical body with an elongated cross section.

A heating melting mechanism consisting of a heating body (6) (heater, etc.) for melting the metal material to be plated is provided on the tip side of the guide portion (4).

In addition, at a position opposite to the copper strip passing side across the discharge nozzle (5), a gas injection port (force) is provided at the nozzle opening, and a force is provided to the hot-dip plated metal (A) discharged from the nozzle opening. On the other hand,
It is designed to spray hot gas in the direction of the copper strip. The slit width X of this gas injection port (7) is generally 2 to 5
It is composed of about 0 parrots.

Note that the plated metal material supply device (1) includes a feeding mechanism (not shown) consisting of a feeding roller or a cylinder device, etc. in order to feed the solid phase plated metal material (2) in the direction of the discharge nozzle.
have.

In the plated metal material supply device (1) as described above, the M band (3) is passed upwardly at a predetermined interval.

Inside the plated metal material supply device (1), the solid phase plated metal material (2) is sequentially fed in the direction of the supply port (5), and the heating element (6)
It is melted sequentially from the tip side just before the supply port, and the supply port (
5).

High-temperature gas with a temperature higher than the melting point of the plating metal material (Q) is sprayed from the gas injection port (7) onto the hot-dip plated metal t thus discharged. The hot-dip plating metal (A) is atomized by this gas spraying, and the atomized molten metal particles (a
t is attached as a plating film (8) to the steel strip (3) through which the plate is passed.

In addition, in the above device, the guide part (4) and the supply port (5)
The diameters of the two do not necessarily have to be the same; for example, the supply port may have a smaller diameter.

Figure 2 shows an example in which the plating metal material (2) is melted outside the supply port (5), and a heating body (9) (radiant (heater, etc.) is provided.

Further, a heating element (11) serving as a preheating mechanism for the plated metal material is provided on the tip side of the guide part (4).

Note that the other configurations are the same as those shown in FIG. 1.

In this method, the plated metal material (2) is sequentially melted by the heating element (9) when it comes out from the supply port (5),
5) Since no molten layer is formed inside the guide part, the molten metal is inserted between the inner wall surface of the guide part and the plated metal material, and the plated metal,
It is possible to appropriately avoid troubles that hinder the continuous supply of lumber.

In addition, since this method melts the metal material to be plated from its surface layer, the number of melting cells is smaller than that of the method θ) in FIG. 1, and therefore it is suitable for thinning.

In addition, Figures 3 and 4 show the guide part (4) and the supply port (
5) is provided facing downward, and in the present invention, there is no restriction on the direction of the supply port, etc. As in the stiff embodiment, the problem of molten metal being inserted downward (by rubbing, θ into the guide portion as described above) can be more reliably avoided.

In the present invention, the temperature of the high-temperature gas may be determined by the positivity between the melting point and the boiling point of the metal material.

However, if the gas temperature is close to the boiling point of the plated metal material, 6
There are problems such as evaporation of molten metal, so in reality, taking into account cooling by radiation to the surroundings, [melting point + 100°C] ±
4. It is preferable to set the temperature to about 50'C. [7 Once upon a time,
For example, when the plating metal material is Zn, the
A gas temperature of the order of °C is preferred, especially 500 °C ± 20 °C.
A temperature of about 'C is most preferable. Also, if the flow rate of the high temperature gas is too high, the particles will scatter too much, and if it is too low, the atomization will not be sufficient.
It is preferable to set it as m/s 8 degrees.

In the present invention, the distance between the device (1) (!: copper strip (3) can be relatively wide. This θ) interval is usually 2 to 50 mm.
You can take the level of familiarity.

Further, there is no particular limitation on the mail order direction of the IA belt (3), and it can be passed in any suitable direction, such as downward or in a nearly horizontal state.

In the method of the present invention, it is also possible to plate the steel strip (3) at room temperature, but in that case, the strip will thermally expand unevenly due to a rapid rise in strip temperature due to contact with molten metal. In order to prevent this, there is a risk of the board becoming defective.
It is preferable to preheat the steel strip (3) to a predetermined temperature (temperature around the melting point of the plated metal material) and then plate the steel strip.

Further, the embossed film (8) formed as described above may have some unevenness in adhesion, and in order to make this unevenness uniform, a uniformization treatment can be performed by surface conditioning molding. As this surface conditioning device, for example, an ultrasonic vibration type device (so-called ultrasonic iron) having an ultrasonic vibrator is used. This device is held by a cylinder device or the like having a buffer mechanism, and its diaphragm is brought into light contact with the surface of a copper strip on which a plating film has been formed, and ultrasonic vibrations are applied to the plating film to form a film on the plating metal. The thickness is made uniform.

In addition, the plating process according to the present invention also improves the wettability of the plating,
To ensure adhesion, a non-oxidizing atmosphere (e.g. Hz
: 20-25%, N2:80-75% mixed gas)
It is preferable to do it indoors.

Also in the method of the present invention, it is preferable that the surface of the steel strip of the plating rudder 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, A
Including t-Zn alloy plating, Co-Cr-Zn alloy plating (e.g. 1%Co-1%Cr-Zn alloy plating), kl-Mg-Zn alloy plating (e.g. 51
Az-0,6%Mg-Zn alloy plating), At-8t
-Zn alloy plating (e.g. 55% kl -1,6
% 5t-Zn alloy plating), 5i-ht gold alloy plating (
For example, it is possible to perform 10-chi 5i-At alloy plating), 5n-Pb alloy plating (for example, 10% 5n-Pb alloy plating), etc.

In addition, in the above embodiment, the plating metal material (2) is supplied to one side of the copper strip (3), but in the case of vA band surface plating, both sides of the copper strip are supplied. A device (1) is arranged,
Needless to say, plating is performed on each side. In this case, plating on both sides does not need to be performed at the same position in the line direction.

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 plate, it is possible to easily perform double-sided dissimilar plating. For example, a steel plate having an Fe-Zn alloy plating film on one side (painting surface) and a Zn plating film on the other side (bare surface) can be obtained as an outer panel material for home appliances and the like.

In the above embodiments, plate-shaped metal materials (2) were used in all cases, but instead of this, for example, powder-like materials may be used. In this case as well, the plating metal material (2) is filled into the guide portion (4) and sent toward the nozzle by a suitable feeding means.

〔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 dross generated when a plating bath is used, there is no loss of plating metal other than adhesion to the copper 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, the components in the plating film are made 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 alloy platings, it is only necessary to replace the plating metal material supplied to the copper strip, and there is no need for large-scale work such as changing baths or moving pots, so various platings 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, multilayer plating, double-sided differential thickness plating, double-sided dissimilar plating, etc. can be easily performed. Can be done.

In addition to these advantages, handling of the plated material is extremely easy because the solid-phase plated metal material is fed, melted just before the plating area, and then adhered to the metal plate. Moreover, the amount of plating deposited can be controlled by the feeding speed of the solid-phase plated metal material, and therefore a high degree of accuracy in the amount of deposited material can be ensured.

In addition, the present invention atomizes the hot-dip plating metal by spraying hot gas at a temperature higher than the melting point onto the molten plating metal material, so that the hot-dip plating metal is directly attached to the metal plate surface as a plating film. The distance between the plated metal supply device and the metal plate to be passed can be kept relatively wide, and a uniform plating film can be obtained without being affected by plate photography, etc., and there is no possibility of collision between the plate and the nozzle. Problems can be appropriately prevented.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention. FIGS. 2 to 4 are explanatory diagrams showing other embodiments of the present invention, respectively. In the figure, (1) fitting metal material supply device, (2) fitting metal material, (3) copper strip, (5) supply port, (61
(9) is a heating body, (7) is a gas injection port, (A) is a hot-dip plated metal, and (a) is a particle.

Claims (1)

[Claims] The solid phase plating metal material that is continuously supplied is melted sequentially from the tip side near the metal plate through which the plate is passed, and the melting point of the plating metal material is reduced in the direction of the steel strip. Production of a molten galvanized metal plate characterized by atomizing the molten galvanized metal by spraying high temperature gas at a temperature above, and adhering the atomized molten galvanized metal as a plating film to the metal material through which the plate is passed. Method.