JPS63114982A - Continuous metal plating device for steel sheet - Google Patents

Abstract

PURPOSE:To obtain a smooth and beautiful continuous plating without using a plating bath by providing a means for successively sending out a plater metal sheet, bringing the sheet into contact with a steel sheet, heating and plating the sheet, and then regulating the surface. CONSTITUTION:The plater metal sheet 10 is sent onto the surface of a band steel 9 traveled by a roller 11, and brought into contact with the band steel. The band steel 9 and plater metal sheet 10 are preheated, and the plater metal is melted at the contact part of the plater metal sheet 10 with the band steel 9 and deposited on the surface of the band steel 9. The plater metal sheet 10 is preheated by an induction heater 16, etc., as required. The surface regulating device 14 is brought into contact with the surface of the band steel 9 deposited with the plater metal at appropriate pressure, and ultrasonic vibration having appropriate frequency and output is imparted to an ultrasonic vibrator 15. By this method, the plater metal spreads over the whole band steel 9, and a coating film analogous to that obtained in the conventional hot dipping is formed.

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention relates to an apparatus for continuously plating various plating metals by contacting and welding them to the fs plate surface. The purpose is to efficiently and beautifully coat the surface of a steel strip to be plated, and to solve various problems observed in conventional hot-dip plating operations.

<Conventional technology> Conventionally, as a method for forming a plating film on the surface of a steel sheet through an alloying reaction, hot-dip plating is a method in which the steel sheet or steel strip to be plated is immersed in pre-molten plating metal. .

This method can be divided into several processes depending on the pretreatment method for the surface of the steel sheet before being plated, but if we focus only on the plating part, the basics are the same for all of them.

As an example, a steel strip is plated continuously. The continuous hot-dip galvanizing line (C, G, L,) will be explained.

FIG. 3 shows an example of C, G, and L.

In Fig. 3, (1) is a direct flame heating zone that burns off oil and dirt on the surface of the steel strip (9) and heats the steel strip to a predetermined temperature, and (2) is an oxide film on the surface of the steel strip that is heated in the atmosphere. (3) is a cooling furnace that cools the steel strip according to a predetermined heat cycle.

Heat treatment in the pretreatment furnace of (1) to (3) above.

The surface-cleaned steel strip is immersed in a molten zinc bath (4).

Here, a hot dip galvanized film is formed on the surface of the steel strip.

The copper strip is then continuously withdrawn from the molten zinc bath, the amount of coating being controlled by a gas restriction nozzle (5) placed directly above the bath. After the coating amount has been adjusted, the plated steel strip is subjected to a predetermined surface adjustment using a minimum spangle device, a galvaneal device, etc. (6).

The hot-dip plated steel strip obtained by such a process has a relatively beautiful surface and excellent corrosion resistance, so it is widely used in practical use.

However, conventionally, building materials, pipes, and home appliances.

In the automotive industry, this product has been primarily used for interior panels, but recently it has been used mainly for home appliances and automobile exterior panels, with surface uniformity and smoothness more than ever before.

Beauty is sought after. Furthermore, the variety has a difference in thickness of 9.
Demand for new products such as single-sided galvanized steel sheets and high-strength galvanized steel sheets aimed at reducing the weight of structures is increasing. For this reason,
Problems with conventional plating quality and the plating process itself are becoming apparent.

Problems can be classified as follows.

(2) Problems associated with using a hot-dip plating bath that constantly melts and holds a large amount of plating metal.

■Problems caused by applying the gas squeezing method to adjust the amount of plating deposited.

■Problems caused by using a long pretreatment furnace.

Furthermore, the content of the problems regarding each item classified above will be explained in detail below.

■Problems associated with the use of continuous dipping plating baths 1) Fe from the surface of the steel strip is eluted into the plating bath, and
Dross often occurs due to oxidation of the plating metal, and this must be pumped up and removed, resulting in loss of the plating metal other than that attached to the copper strip.

2) Impurities are likely to be mixed into the plating bath, such as the generation of dross and the inclusion of brick debris constituting the pot that holds the bath, and these impurities adhere to the copper strip, degrading its appearance.

3) The trace elements in the plating metal ingots that are put into the bath, the components that adhere to the copper strip, and the components that are discharged to the outside as by-products such as dross are different, so the necessary elements are contained as per the target. It is difficult to adjust and control the plating bath components.

This causes various plating defects such as poor plating adhesion and poor alloying of the galvanic material.

4) Rolls for threading copper strips, roll support arms, bearings, etc. in a high temperature, highly corrosive plating metal bath.

It is necessary to immerse mechanical parts made of fl.

This causes problems such as progression of corrosion of these plated metals, generation of dross accompanying this, and deterioration of the appearance of the plated 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 the threading roll (7) 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.

Furthermore, the squeezing roll (8) installed before the gas squeezing may also cause scratches on the surface of the strip due to contact between the roll and the strip, and the attachment of minute dross particles.

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

Work near high temperatures and large amounts of plating baths, such as removing top dross that accumulates on the bath surface, initial threading of copper strips into the bath, and maintenance of rolls in the plating bath, places a burden on one worker. , and dangerous.

7) Pot - Since only one type of plating can be done per base,
When performing various types of dissimilar plating, it is necessary to perform operations such as changing the bath by pumping out the bath, or preparing in advance a pot in which dissimilar plating metals are melted and moving the pot.

These tasks require a lot of time, effort, and additional bots.

8) If double-sided plating and single-sided plating are produced using a single piece of equipment, it is necessary to change the plating equipment for the pot section, which, like the above, requires a lot of time and labor in addition to equipment investment.

■Problems associated with adjusting the amount of deposition 1) Adjustment of the amount of deposition by gas throttling is performed using gases such as air, combustion generated gas, nitrogen gas vapor, etc., but this requires the operating cost of a pressure boosting blower. In addition, in the case of combustion generated gas, fuel costs are required, and in the case of nitrogen gas steam, gas costs, etc. are required.

Additionally, accompanying gas temperature adjustment equipment, gas amount, and gas pressure adjustment equipment are required.

2) When changing the target coating amount, it takes time to adjust the gas restriction conditions, so it is not possible to immediately obtain a product with the target coating amount.

3) Since the pressure and flow velocity distribution of the gas throttle gas are not necessarily uniform in the width direction of the steel strip to be plated, it is not easy to obtain a uniform coating amount in the width direction.

4) During gas throttling, when the gas from the nozzle collides with the hot-dip coating on the surface of the steel strip, minute droplets of plated metal are generated, which adhere to the plated surface and deteriorate the appearance.

In addition, these droplets adhere to the gas discharge part of the gas throttle nozzle and its surroundings and disturb the gas pressure and flow velocity distribution, which tends to cause unevenness in the amount of plating deposited.

5) When the gas is squeezed, the fluidity of the plating flowing down the steel strip surface differs in each part, so large to small wave patterns remain on the plating surface, which causes problems in appearance.

It is also known that the single-layer phenomenon can be alleviated if an oxide film is not formed on the plating surface in an inert gas atmosphere, but conventionally it has not been possible to perform all gas squeezing work in an inert gas atmosphere. Regarding the method, there are many improvements in terms of equipment and operation.

6) Droplets generated due to gas restriction are deposited on the surface in an oxidized state. This is discharged out of the bath as top dross, resulting in loss of plating metal.

Also, a lot of effort is required for discharging.

7) There is a range of adhesion amount that can be adjusted by gas restriction, and it is extremely thin (approximately 30 g/rrr or less).

Production of thick plating (more than about 500 g/rrl') is difficult.

That is, in the case of thin plating, the amount of plating cannot be reduced by the gas collision force, and in the case of thick plating, it is difficult to keep the plating surface smooth and beautiful.

(2) For Si and Mn-added high-strength steels with a front fork of 1 J cup, in a pretreatment furnace. During direct heating, reduction, and cooling operations, Si, an easily oxidizable element,
, Mn is oxidized and concentrated on the surface layer, resulting in a phenomenon in which plating adhesion and wettability are inhibited.

Such a phenomenon cannot be avoided as long as a conventional long pretreatment furnace is used, and the types of steel that can be used as high-strength steel are limited.

<Summary of the Invention> The present invention has been made to improve the drawbacks of the above-described conventional plating method using a hot-dip metal bath, and aims to provide a continuous metal plating apparatus that does not require a plating metal bath. It is.

For this purpose, the present invention includes a plated metal plate feeding device, a plated metal plate heating device, and a plated surface conditioning device.

The plated metal plate feeding device brings plated metal plates of the same width into contact with the surface of the steel plate to be plated in a substantially perpendicular direction, and sequentially feeds the plated metal plates. This plated metal plate is heated to a predetermined temperature by a heating device, and is plated while contacting the surface of the steel plate to be plated.

The applied plating is adjusted by a plating surface adjustment device.

<Example> The apparatus of the present invention will be described below based on an example thereof. First, the outline of the device will be explained using FIG. 1.

A plated metal plate (1o) adjusted to a predetermined size is sent by a feed roller (11) onto the surface of a running steel strip (9) adjusted to a predetermined temperature, and brought into contact therewith. At this time, it is necessary to heat the steel strip and the plated metal in advance so that the plated metal melts at the portion (12) of the plated metal plate that contacts the steel strip.

Plated metal is melted out from the tip of the plated metal.

As shown by the shaded area in (13), it adheres to the surface of the copper strip, but
At this time, the width of the plated metal plate (10) is preferably determined in accordance with the width of the copper strip so that the attached plated metal covers almost the entire width of the surface of the copper strip.

The feeding speed of the plated metal plate is determined by calculating the amount of plated metal required, assuming that the target coating weight is applied to the entire surface of the steel strip.

All you have to do is decide. Further, when it is necessary to preheat the plated metal plate, a suitable heating device such as an induction heating device (16) is provided.

If the plating film is welded from the plated metal sheet as it is, there will be slight unevenness in the amount of adhesion and it will be difficult to spread over the entire width of the steel strip, so a device is required to make the film uniform. As an example of this, FIG. 1 shows an ultrasonic vibration type surface conditioning device (14).

The surface conditioning device (14) is equipped with an ultrasonic transducer (15) that emits a frequency suitable for the conditioning device.

Gives output ultrasonic vibration.

When this surface conditioning device is brought into contact with the f;R't; surface to which plated metal has adhered, the plated metal will be
A plating film similar to ordinary hot-dip plating is formed by spreading uniformly over the entire surface of the copper strip.

The effect of applying ultrasonic vibration when bringing this surface conditioning plate into contact significantly reduces plating wetting defects.

It provides a uniform and smooth coating on two surfaces.

In the present invention described above, the bonding between the plating film and the copper strip is based on the mutual diffusion phenomenon of the amount of metal, which is the same as in the normal hot-dip plating method, and the surface of the steel plate before contact with the plated metal plate is free from oxide contamination, etc. The surface must be clean and free of dirt.

Therefore, the present invention shown in FIG. 1 can be applied to a flux-treated steel plate surface in the atmosphere. or,
For steel plate surfaces that have been subjected to reduction treatment in a furnace, it is necessary to carry out the process in a non-oxidizing inert gas or reducing gas atmosphere.

The steel strip to be plated only needs to have a clean surface, and can be applied to steel strips just before entering a bath in a conventional hot-dip plating line or steel strips exiting a continuous annealing line. It goes without saying that it can also be used in combination with another type of surface cleaning device.

The present invention will be further explained based on an example of the implementation device shown in FIG.

FIG. 2 shows two apparatuses of the present invention connected to the rear end (17) of the conventional hot-dip plating equipment pretreatment furnace shown in FIG.

The steel strip (9) is placed in a sealed box (18) with its surface reduced and cleaned in a conventional pretreatment furnace for hot-dip plating
) to enter an inert or reducing atmosphere, and then heat the heating device (1
9).

On the other hand, the plated metal plate (10) is fed from the front and back surfaces of the steel strip to the surface of the steel strip, and welded thereon. At this time, a large number of plated metal plates are set in the holder (20),
The metal plate feed cylinders (21) and (22) automatically feed the metal plate into the feed roll (11).

The plated metal plate is fed toward the surface of the steel strip by a feed roll in an amount commensurate with the amount consumed by plating.

Furthermore, the plated metal plate is preheated by a heating device (16) as necessary before welding. A surface conditioning plate (14) equipped with an ultrasonic vibrator is brought into proper contact with the surface of the plated metal after welding. The entire surface conditioning device is held in a special cylinder (23) equipped with a shock absorber, and has a structure that allows extremely light contact and allows it to be retracted to a predetermined position when not in use. .

Further, a heating device is incorporated in the second surface adjustment plate, and when it is used, it is heated to a predetermined temperature.

After the surface-conditioned steel strip is welded and plated, it undergoes various treatments, is cooled, and then exits from a sealed box that is kept inert or reducible.

As an example, FIG. 2 shows an example in which the alloying treatment is performed using a single alloying heating furnace (24). The steel strip after plating is heated in a heating furnace (24) using an electric induction heating method, etc., if necessary.
At , the steel strip is heat-treated and alloyed with the plating and the steel strip base.

(25) is a cooling device using gas blowing in an inert or reducing gas atmosphere, (26) is a water cooling device in the same atmosphere, and (27) is a drying device after water cooling in the same atmosphere. It is.

The steel strip after weld plating and 9-alloying treatment is cooled to room temperature in an inert or reducing gas atmosphere, and then exits from the same atmosphere into the atmosphere.

(28) is a steel strip surface treatment device before welding,
The purpose of this method is to remove difficult-to-metal coatings such as Si and Mn that are concentrated and formed on the surface when a high-SL, Mn-containing high-strength steel strip is heated and reduced in a pretreatment furnace.

Here, the difficult-to-metal coating is removed by mechanical polishing by brushing or the like, and the electrical coating is destroyed and removed by electrical discharge treatment or the like. It goes without saying that this atmosphere is also inert or reducing.

Although FIG. 2 shows an example of a horizontal device, a vertical arrangement may also be used. that's all.

The present invention can eliminate most of the drawbacks of conventional hot-dip plating methods, and its effects are as follows.

■ Benefits from not requiring pickled plating 1)
There is no reaction between the plating metal and iron and no generation of dross due to the oxidation of the plating metal.

There is no loss of plated metal other than adhesion to the ms.

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

3) Since the plated metal is directly welded, almost the same components as those of the plated metal plate are plated, making it easy to control the components in the plated layer.

4) There is no need to use parts immersed in a bath, reducing downtime due to repair or replacement of machine parts due to corrosion.

5) Since there is no need to use rolls during plating, product quality does not deteriorate, such as deterioration of appearance due to transfer of roll groups in the bath or bending due to squeezing rolls.

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

7) When performing various types of alloy plating, it is possible to perform various types of plating easily by simply replacing the plating metal plate welded to the copper strip, without requiring major work such as changing baths or moving pots. be.

For example, various Zn-A1 alloy plating (5~100%A
1) Zn plating without PB for the purpose of eliminating spangles can be easily achieved.

8) By selecting whether or not to use plated metal plate feeding devices disposed on the front and back sides of the copper strip and by changing the feeding speed, plated steel strips of various shapes can be easily obtained.

For example, by stopping the feeding of one side of a single-sided plated steel plate and changing the feeding speed of the two sides, a steel plate with differential thickness can be easily produced.

Furthermore, it is also possible to manufacture steel sheets coated with different alloys, each of which has a different plating layer composition on each of its nine sides.

(2) Advantages in adjusting the coating amount 1) The coating coating amount can be adjusted basically by adjusting the feeding rate of the plated metal plate. Therefore, there is no need for the gas restriction conventionally used in hot-dip plating, and there is no need for a gas restriction nozzle that is troublesome to maintain, or for the accompanying temperature, volume, and pressure adjustment membranefffl. Also, the operating cost of the booster blower.

Fuel costs when using combustion generated gas and gas costs when using nitrogen gas can be reduced.

2) When changing the target coating amount, it is only necessary to change the plated metal plate feeding speed, and the coating amount can be quickly changed.

3) Surface conditioning after plating welding is performed by pressing a smooth surface conditioning plate parallel to the steel strip surface, making it possible to obtain a uniform coating amount in one width direction.

4) After plating, by keeping the plated steel strip in an inert or reducing atmosphere until the temperature drops to around room temperature, surface oxidation of the plated film and wavy patterns on the plated surface due to gas restriction will not occur. Beautiful surface texture can be obtained.

5) The amount of coating can be adjusted by adjusting the feed rate of the plated metal plate, making it possible to obtain products with extremely thin to extremely thick plating, which is impossible with current gas squeezing methods.

(7) IJ 1) By not using a plating bath or a gas throttle, it is easily possible to seal the plating assembly with an inert or reducing gas.

Therefore, the formation of an oxide film on the plating surface is suppressed, and a product with a beautiful surface can be obtained.

2) Immediately before plating, the surface of the steel strip to be plated can be easily cleaned (e.g., polished with a brush, destroyed by electrical discharge), which prevents the formation of an oxide film that is difficult to plate on the surface during continuous annealing. It can also be applied to steel types that are difficult to plate, such as Si and Mn-added high-strength steel, whose use was restricted in conventional hot-dip plating.

<Effects of the Invention> As explained above, according to the plating apparatus of the present invention, metal plating can be continuously performed without using a plating bath, which has conventionally caused various problems.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an outline of an embodiment of a plating apparatus according to the present invention, FIG. 2 is a side sectional view thereof, and FIG. 3 is a side view showing an example of a conventional apparatus. DESCRIPTION OF SYMBOLS 10... Plated metal plate, 11... Plated metal plate feeding device, 12... Plated metal plate, copper strip contact part, 13.
...Welded plating metal coating, 14... Plating surface conditioning device. 15... Ultrasonic vibrator, 16... Plating metal plate heating device, 17... Hot-dip plating equipment pre-treatment furnace rear end, 18.
... Seal box, 19... Steel strip heating device to be plated. 20... Plated metal plate holder, 21... Plated metal plate feeding cylinder, 22... Plated metal plate feeding cylinder, 23... Cylinder for holding surface conditioning device. 24... Alloying heating furnace after plating, 25... Air cooling device. 26...Water cooling device, 27...Drying device, 28...
Figure 1 Procedural amendment for pre-treatment equipment for galvanized steel strip (voluntary) Showa b/1999/February J) f'+, i'l'l'+17゛1゛i Akio Kuroda ff
,'i,ft1ishineY+)
], Incident Display Showa b/Year Patent Application No. 26/'7/l
I-No. 2, the name plate of the invention /) is attached to the Itoki Rei Mefu, ■ 3. Person making the amendment Relationship with the license Applicant (412) Nippon Kokan Co., Ltd. 4, Agent Specification TDcP Detailed Explanation of the Invention and Drawing (Figure U) Correction Contents 1 In the middle cylinder of the present specification, page 15, line 5, the term “electric induction heating method, etc.” has been replaced with “electromagnetic induction heating method, etc.” etc.” and amend it. At the beginning of the 5th line on page 17 of the second edition, the words ``of steel plates'' are corrected to ``of steel plates.'' At the beginning of the 9th line of page 17 of the same book, there is the word ``good'', followed by ``,''
and join. "Figure 2" in the attached drawings of the weak original application is corrected as shown in the attached sheet.

Claims (1)

[Claims] A plated metal plate feeding device that sequentially feeds plated metal plates of the same width to a steel plate to be plated by bringing them into contact with the surface of the plated metal plate in a substantially perpendicular direction; a heating device that heats the plated metal plates; and a heating device that heats the plated metal plates; 1. A continuous metal plating device for steel sheets, comprising a plating surface conditioning device for adjusting the plating surface.