JPH01165753A - Method for replenishing component to plating bath - Google Patents

Abstract

PURPOSE:To prevent the variance in the composition of a moltenmetal plating bath and to form a high-quality plating layer by replenishing components to the hot-dipping bath contg. plural components from a premelting pot contg. the melt of a plating bath forming metal or alloy at the time of plating a band steel by hot dipping in the bath. CONSTITUTION:The annealed band steel 6 is passed through the inside of the plating bath 1 contg. a Zn hot-dipping bath 2, for example, from a snout 7, and vertically pulled up by a sink roll 3. In this case, a small amt. of Al is contained in the Zn hot-dipping bath 2 to form a highly adhesive Zn plating layer on the surface of the band steel 6, and an Fe2Al5 layer as the Al-enriched layer is formed between the band steel 6 and the Zn plating layer. The premelting pots 8 and 10 respectively contg. molten Zn 9 and the melt 11 of an Al-Zn alloy are prepared, and the materials are replenished by pumps 12 and 14 into the plating bath 1 at a controlled rate when the amt. of the plating bath 2 is decreased. When spangles (flower pattern) are to be formed on the plating surface, the necessary Pb 20 is supplied in the form of fine particles into the plating bath 2 from a hopper 18.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for replenishing components to a plating bath in continuous molten metal plating.

Prior art and its problems Continuous hot-dip plating involves immersing a continuously running copper strip in a bath of molten plating metal for a predetermined period of time, and then removing the copper strip from the bath and applying gas wiping to the surface. This is a plating method in which a desired plating is applied to the surface of a steel strip by adjusting the plating weight to a predetermined coating weight, and hot-dip galvanizing is a typical example.

Originally, galvanized steel sheets were used as building materials due to their excellent corrosion resistance.
Widely used as steel sheets for home appliances and automobiles, hot-dip galvanizing currently has inferior surface quality compared to electrogalvanizing, but it consumes less energy and the cost of molten metal for plating is lower. It is attracting attention in the mass production of galvanized steel sheets because it can be easily made thick.

By the way, in continuous hot-dip galvanizing, in addition to using a pure zinc bath, hard and brittle Fe-
AJ2 may be added to the zinc coating in order to suppress the growth of the Zn alloy layer (r phase: Fe5Zn2+) and improve plating adhesion. That is, by forming an A1-enriched layer (Fe2 AJ25, etc.) at the interface between the plating layer and the base steel, the Fe-Zn alloy layer at the interface between the zinc and the base steel is moderately suppressed, and the plating layer is This prevents flaking (powdering).

In addition to the addition of Aft mentioned above, incomplete PB may be added to form spangles (flower patterns) on the plating surface, and the addition rate of AJ2 and PB varies depending on the purpose of the galvanized steel sheet. There is.

In such continuous hot-dip galvanizing, the components (Zn, An, Pb) in the plating are i) carried out by the plating layer adhering to the surface of the copper strip, and if) floating dross is formed and its flow out of the plating bath. Since it decreases due to exclusion, it is necessary to replenish the decreased components to the plating bath.

A conventional method of replenishing components to a plating bath will be explained below.

First, the composition and supplementary components (ingot) of the hot-dip galvanizing bath are shown in Table 1 below. Note that hot-dip galvanized steel sheets generally include not only pure zinc plating baths but also steel sheets having bath compositions as shown in Table 1.

Table 1 To explain representatively the types Gl and GA in Table 1 above, when the liquid level of the plating bath decreases, about 1 ton of 0.
As a result of putting ingots of 3~0.5wt%AJ2-Zn alloy into a plating bath and analyzing the bath components over several hours, it was found that as the AJZ concentration decreased, one
10wt% AJ of about 0kg! - Ingredients were replenished by putting an appropriate number of Zn alloy ingots into the plating tank.

Note that Aj! has an AIL concentration higher than the target AIL concentration of the bath components! -The reason for introducing the Zn alloy ingot is that the reduction rate of Zn in the plating bath is higher than the reduction rate of Al due to the formation of the Aρ enriched layer (Fe2AI15 etc.) mentioned above and the formation of floating dross.
This is because the reduction rate of 1 is large.

However, in the above replenishment method using ingots,
It takes time for the ingots put into the plating bath to melt and spread in the plating bath to form a uniform plating bath (the heavier the ingot, the longer it takes). Until the next time, Rakuchu's A
Since the iL concentration continues to decrease, as shown in the comparative example in FIG. 7, the A1 concentration during plating changes greatly depending on the pitch (several hour intervals) at which 10 wt% Aj2-Zn alloy ingots are introduced.

If the Ai concentration in the plating bath fluctuates in this way, the uniformity of the A1-enriched layer described above will be impaired, making it impossible to obtain stable plating quality. When the value of plating deviates from the target value, there will be more plated areas, leading to a decrease in plating quality.

In addition, in the conventional component replenishment method described above, the relationship with plating conditions is not considered, and moreover, the AIL content is constant.
Any AI to input JZ-Zn alloy ingot
It is impossible to replenish ingredients at t concentration, and A1 during plating
It is not possible to finely adjust the density.

In recent years, hot-dip galvanized steel sheets have become popular due to their low manufacturing costs.
It is expected that it will be applied to mass-produced automobile exterior panels, but for that purpose it must have excellent adhesion to deep drawing by press forming, and therefore the appropriate A2 The formation of an enriched layer has become essential. Therefore, it is necessary to control the AfL concentration in the plating bath more strictly.

Taking these points into consideration, the conventional component replenishment method by charging ingots has a limit in reducing fluctuations in AfL concentration, and has not been able to stably obtain satisfactory plating quality.

<Object of the Invention> The object of the present invention is to solve the above-mentioned drawbacks of the prior art, to suppress fluctuations in concentration of the components in the plating bath, and to provide components for the plating bath that can stably obtain good plating quality. The purpose is to provide a replenishment method.

<Structure of the invention> Such objects are achieved by the following invention.

That is, the present invention is a method for replenishing components into a plating bath when performing hot-dip plating in a plating bath containing a plurality of components. The present invention provides a method for replenishing components to a plating bath, characterized in that components are replenished from the pre-melt pot to correspond to the amount of decrease in the bath.

In addition, in a method for replenishing ingredients to a plating bath when hot-dip paddy rice is hot-dipped in a plating bath containing multiple components, at least one pre-melt pot in which the replenishing ingredients are melted in advance, and metal lumps or metal powder particles of the replenishing ingredients are used. and at least one hopper containing said pre-melt pot and hopper to provide for replenishment of components from said pre-melt pot and hopper to accommodate required replenishment concentrations and plating bath reductions.

In these inventions, it is preferable that the necessary replenishment concentration and the amount by which the plating bath is reduced are determined by the plating conditions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of replenishing components to a plating bath according to the present invention will be described in detail below with reference to preferred embodiments shown in the accompanying drawings.

FIG. 1 is a side view schematically showing an example of the configuration of equipment for carrying out the method of replenishing components to a plating bath according to the present invention.

In the plating bath 1, the annealed steel strip 6 coming out of the snout 7 is immersed in the molten metal for plating (for example, molten zinc) 2 by the zinc roll 3, and then straightened by the collecting roll 4 and stabilized. After being stabilized by stopping the rocking by the rising roll 5 and being pulled up from the molten metal for plating 2, it is adjusted to a predetermined plating area weight by gas wiping (not shown).

In this way, the steel strip 6 is continuously coated with hot-dip metal.

When performing hot-dip galvanizing, as mentioned above, it is possible to add A1 to the plating bath to improve plating adhesion, or to add a small amount of PB to form spangles on the plating surface. be exposed. Therefore, the composition of the molten metal 2 for plating is AIL-Zn based or /1ft
-Pb-Zn system, etc., and the addition rate of Ai and PB is appropriately determined depending on the use, type, etc. of the galvanized steel sheet to be manufactured.

For example, 1) the composition of the molten metal 2 for plating is 0, 0 1
~0. 2wt% Pb-0,1~0. 2wt
%Aj! - Zn alloy galvanized steel sheet or alloyed galvanized steel sheet (G1.GA), if) zinc-aluminum alloy coated steel sheet (GALFAN) where the composition of the molten metal 2 for plating is 5wt% Al1-Zn alloy, or 1ii) The composition of molten metal 2 for plating is 1.4 wt% S
i-55wt% Aj! -Zinc of 43.6wt%Zn-
Aluminum alloy plated steel plate (GALVALUME) etc.

The uses of i) are mainly for building materials, home appliances, and automobile interior panels, and the uses of if) and jji) are mainly for building materials.

In such continuous hot-dip galvanizing, removal due to the galvanizing layer adhering to the surface of the steel strip 6 and floating dross are generated, and by removing this to the outside of the plating layer, the liquid level of the molten metal 2 for plating decreases. do. Therefore, it is necessary to replenish so as to keep the liquid level constant and to keep the composition of the molten metal 2 for plating constant at the target value.

The floating dross combines with A1 in the molten metal for plating 2 eluted from the steel strip 6 to form Fe2Aj2. This is what has floated to the surface of the plating bath (having a specific gravity smaller than the molten metal 2 for plating), or what has been oxidized by zinc on the bath surface.

In addition, the decrease in the molten metal 2 for plating is due to the fact that each component (Zn, An, Pb) of the molten metal 2 for plating has its content (jIA
It does not decrease in proportion to the degree of That is, regarding the decrease in AIt, since an AIL-enriched layer (Fe2AJ!6 etc.) is formed at the interface between the base steel and the plating layer, the AIL concentration in the take-out is lower than that of the molten metal 2 for plating.
T? ! The composition of the floating dross that is higher than 4 degrees and is removed to the outside of the wiping bath is AfL = Fe = 2 to 4 wt in the molten metal 2 for plating with an Ai concentration of 0.1 to 0.2*t%.
%, and the remainder is Zn, so the decrease in An concentration in the molten metal for plating is more significant than in other components.

Therefore, replenishment of components to the plating bath is necessary for molten metal for plating.
As a result of replenishing the amount so that the liquid level reaches the target value, rather than at a concentration equal to the composition of
It is also necessary to adjust the composition to the target value.

In the present invention, components are replenished into the plating bath as follows. As shown in FIG. 1, Brimeltbots 8 and 10 are installed on the side of the plating bath 1, and the Brimeltbot 8 contains molten Zn9 obtained by melting an ingot, and Brimeltbot 10. A molten Al1-Zn alloy 11 obtained by melting an ingot is stored in the tank.

When replenishing the components, pumps 12 and 14 are operated to supply "molten Zn9 and melted Aj!" - Zn alloy 11 is introduced into plating bath 1 via conduits 13 and 15, respectively.

Replenishment of such components is carried out by adjusting the amounts input from each pre-melt pot 8.10 so as to correspond to the above-mentioned required replenishment concentration and reduction amount of the plating bath. In addition, when the molten metal 2 for plating is a binary alloy, at least two Brimeltbots are required to replenish the components to correspond to the required replenishment concentration and the amount of decrease in the plating bath. Molten Zn from each pre-melt pot 8.10
Adjustment of the input amounts of 9 and molten AJZ-Zn alloy 11 is as follows:
This can be done by using a pump capable of controlling the flow rate as the pump 12.14, or by providing a flow rate regulating valve (not shown) in the middle of the conduit 13.15.

In addition, the form of replenishment may be either continuous replenishment, in which replenishment is performed at any time during plating, or intermittent replenishment, in which replenishment is performed at predetermined intervals. The forms may be different. In addition, when performing intermittent replenishment, it is preferable that the replenishment pitch be as short as possible, since concentration fluctuations in the molten metal 2 for plating will be reduced.

When the liquid level in the pre-melt pot 8.1o decreases, a Zn ingot and an A11-Zn alloy ingot are respectively introduced into the pre-melt pot 8.1o to compensate for the decrease.

The conduits 13.15 are preferably heated and maintained at a temperature above the melting point of the metal passing through them so that molten metal does not solidify within them and cause blockages. Also, conduit 13.1
Input port at the tip of 5! 3! , 151 is the first in plating bath 1
The inside of the steel strip 6,
It may be located on the outside or near the side, and the conduit 13
．． 15 may be branched, and a plurality of inlets 131 and 151 may be arranged at various locations in the plating bath 1. This is preferable because it promotes uniformity of the concentration of the molten metal 2 for plating in the plating bath 1.

In this way, when replenishing the components to the plating bath 1 by charging molten metal, there is an advantage that fluctuations in the bath temperature of the plating bath can be suppressed compared to the conventional method of charging ingots.

Melt Zn9 and Melt A from pre-melt pot 8.10
The means for replenishing the J2-Zn alloy 11 to the plating bath 1 is not limited to the method using the pumps 12 and 14 described above. That is, as shown in FIG.
．． It is also possible to introduce the molten metal 9.11 into the plating bath 1 by inserting the spacer 16 into the molten metal 9.11 of 10 and raising the liquid level to cause overflow. In this case, the amount of molten metal 9.11 introduced is adjusted by the amount of spacer 16 inserted.

In addition, as shown in Figure 3, the pre-melt pot 8.10
It is also possible to make it a closed type, send high-pressure gas into the pre-melt pot 8.10 using the compressor 17, and use the pressure to push out the molten metal 9.11 in the pre-melt pot and throw it into the plating bath 1.

In addition, the AJZ component of plating bath 1 is replenished using molten Aρ-Zn.
The reason for using Alloy 11 is as follows. The bath temperature of the plating bath 1 is such that the composition of the molten metal 2 for plating is 0.1 to 5.
In the case of wt%AfL-Zn alloy, the melting point is about 450 to 480°C, but the melting point of β alone is 660°C, so
When molten A1 is poured into plating bath 1, it solidifies.

On the other hand, if A11-Zn alloy is used, its melting point will be lower (melting point of 10 wt% AfL-Zn alloy is 430°C).
, there is no inconvenience that the paddy coagulates when put into a plating bath. Therefore, in the present invention, when replenishing a metal component having a melting point higher than the bath temperature, an alloy of the metal and another metal, especially the main component metal (zinc in this example), is used. It is preferable to lower the melting point, preferably below the bath temperature, before adding it to the plating bath. However, the present invention does not preclude providing a pre-melt bot for melting Aj2 and replenishing the AJ21L body. In addition, as described below, melting A
The IL pre-melt pot can also be used as a pre-melt bot for replenishing the molten AjZ-Zn pre-melt pot.

As shown in FIG. 5, pre-melt pots A containing molten Zn, pre-melt pots B1 containing molten AfL, and pre-melt pots C, D, E containing molten A11-Zn alloys each having a different Aufi degree, F is provided, one or more of Brimeltbot A%C%D%E%F is arbitrarily selected, and an appropriate amount of molten metal is thrown into the plating bath 1 from each of them.

When the liquid level in either pre-melt pot C%D%E or F decreases, predetermined amounts of molten Zn and molten Aβ are poured into that pre-melt pot from pre-melt pots A and B, respectively. For example, when replenishing pre-melt pot C, the respective input amounts from pre-melt pots A and B are adjusted to be equal to A x ta degree of pre-melt pot C.

When the composition of the molten metal in each pre-melt pot is as shown in Table 2 below, Table 3 below shows an example of replenishment from each pre-melt pot to the plating bath with respect to the composition of the plating bath.

Table 2 Table 3 FIG. 4 is a side view schematically showing another example of the configuration of equipment for carrying out the method of replenishing components to a plating bath according to the present invention. In the equipment shown in the figure, pre-melt pots 8 and 10 similar to those described above and a hopper 18 containing metal powder grains 20 as a supplementary component are installed, and a pre-melt pot 8 is placed in the same manner as described above.
and 10 to melt Zn9 and melt A11, respectively.
-Zn alloy 11 is thrown into the plating bath 1, and at the same time, a predetermined amount of metal powder particles 20 are thrown into the plating bath from the hopper 18. A blade (rotary feeder) 19 is installed at the lower end opening of the hopper 18, and this blade 1
By the rotation of 9, metal powder particles in the hopper are cut out in fixed quantities and thrown into the plating bath 1. Note that, unlike the illustration, the hopper 18 is installed at a position a considerable distance away from the plating bath, and the metal powder particles 20 cut out from the hopper 18 are conveyed by a conveyor to the plating bath 1.
You may also put it in.

In hot-dip galvanizing, a small amount of PB may be added to the molten metal 2 for plating in order to form spangles on the plating surface, as described above. That is, the composition of the molten metal 2 for plating is a Pb-Al1-Zn alloy, and this pb acid component can be replenished by introducing metal powder particles 20 using pb grains. Note that, since the melting point of PB is 327°C, which is lower than the bath temperature (450 to 480°C) of plating bath 1, the PB particles introduced into plating bath 1 quickly melt and diffuse.

The particle size of the metal powder particles 20 is not particularly limited, but is preferably about 1 to 101111+. If it is less than 1 mm, minute particles will float in the bath and easily adhere to the copper strip.
Further, if the distance exceeds 10 mm, the accuracy of density adjustment becomes rough. Note that the metal powder particles 20 are not limited to PB particles;
- It may be grains of Zn alloy, or powder grains of other metals or alloys.

In such equipment, when the molten metal 2 for plating is a binary alloy, at least one pre-melt pot and one hopper are used to replenish the necessary replenishment concentration and components corresponding to the decrease in the plating bath. It's good to have one each.

In the present invention, the amount of component replenishment can be determined by, for example, a method of timely analyzing bath components and based on the analyzed values, or a method of determining based on estimated values determined empirically. However, as described below, it is preferable to determine the necessary replenishment concentration and the amount of decrease in the plating bath from the plating conditions, and replenish the components based on this.

The present inventors have determined that the cleaning bath composition is 0.05 to 0.20 wt%.
As a result of conducting experiments and discussions to investigate the relationship between the amount of reduction in the A2 component and the plating conditions regarding hot-dip galvanizing using AIL-Zn, the following findings were obtained.

■ An enriched layer (Fe, A) at the interface between the base steel and the plating layer.
J! , etc.), the A2 concentration in the plating layer is higher than the AfL concentration in the paddy rice plating bath. Furthermore, the AIt concentration in the plating layer is not always constant with respect to the amount of plating deposited, but is a function of the amount of plating deposited, as shown in FIG. Therefore, the amount of reduction due to the removal of AI can be known from the amount of plating deposited.

■The main component of the floating dross is Fe2Al1. Analysis of the components of this dross revealed that Afl=Fe=2 to 4 wt%, with the balance being Zn.

Therefore, the amount of decrease in the AJ2 component due to the generation of floating dross is equal to the amount of Fe eluted from the copper strip, and by understanding this, it is possible to know the amount of decrease in Al1 due to the floating dross.

From the above (1) and (2), the total reduction in Zn%AIL in the plating bath is expressed by the following formula.

AJ2 total decrease amount = f (V, B, C, θ, W) Zn total decrease amount = g (V, B, C, θ, w) V line speed B; plate width C: AJ2 concentration in bath θ: penetration Sheet temperature W; From the amount of plating deposited, the amount of decrease in Zn and AJl during plating and Z
It has been found that each reduction rate of n%An can be determined by the plating conditions (plating amount, plate width, line speed, plate temperature, etc.).

Previously, AJ! of Plating Rakuchu! :A higher than a degree
Simply put the AIL-Zn alloy ingot of ILvA degree (content rate) into the plating bath, and depending on the plating conditions,
There was no change in the supply concentration of 81. In contrast, with the present invention, which determines the replenishment concentration of the necessary bath components and the amount of reduction in the plating bath based on the plating conditions, it is possible to replenish the components more appropriately, and the concentration of each component during plating can be more narrowly controlled. can be limited to a range, and also
Even if the plating conditions (plating amount, plate width, line speed, plate temperature, etc.) change, it can be accommodated.

Generally, there are n pre-melt pots (n≧2), and C
n is the concentration of the specific component in the nth pre-melt pot, Q
If n is the supply amount from the nth pre-melt pot,
The required replenishment amount Q" and the required concentration C" are expressed by the following equations.

Q"=Ql+Q2+""QnThis Q", C" is determined from the above plating conditions, and the Q",
Replenishment may be performed by adjusting Ql to Qn so that the value becomes C''.

Above, the method of replenishing components to a plating bath according to the present invention has been representatively explained for hot-dip galvanizing containing AJ2 components, but the present invention is not limited to hot-dip galvanizing, such as hot-dip tin plating, tin-lead alloy plating, hot-dip galvanizing It can be applied to all types of molten metal plating such as aluminum plating.

<Example> (Example 1 of the present invention) Hot-dip galvanizing was performed under the following conditions using equipment configured as shown in FIG.

Plating bath composition: 0.15±0.01wt%An (target straight)-Zn first
Pre-melt pot composition: Pure Zn Second pre-melt pot composition: 2wt%Aj2-Zn Plating conditions Plate thickness: 0.7 mm Plate width: 1200 mm Line speed: 120 m/min Plating deposit (one side): 90 g/rn' This plating condition Calculated from, the Aj2 concentration to be replenished is 0.6wt%
, the reduction amount of the plating bath is 30 kg/min.
Therefore, 21 kg of pure Zn was collected from the first Brimelt pot.
/ min, 2wt% Al from the second Brimelt bottle
1-Zn alloy was supplied at a rate of 9 kg/win. The form of replenishment is Z so that the above replenishment amount is on average.
n: 630 Kg, Z n -A 11 alloy 2
70 Kg was carried out intermittently with pitches of 30 minutes. Also,
The conduit between each pre-melt pot and the plating bath is heated by a heater to prevent the molten metal from solidifying within the tube.
Heated to ~4-80°C.

(Example 2 of the present invention) Hot-dip galvanizing was performed under the same conditions as Example 1 of the present invention using equipment configured as shown in FIG.

The form of replenishment from the pre-melt pot to the plating bath was as follows: pure Zn was added at 21 g/min from the first pre-melt pot, and 2 wt%Aj from the second pre-melt pot! -Zn alloy at 9K
It was continuously replenished at g/min. The conduit between each Brimetre pot and the plating bath was heated to approximately 450-480° C. by a heater to prevent the molten metal from solidifying within the tube.

(Example 3 of the present invention) Hot-dip galvanizing was performed under the following conditions using equipment having the configuration shown in FIG.

Plating bath composition: 0.15±0.01wt%AJ20,
0 1 ~ 0. 0 2wt% PB balance
Zn 1st premelt pot composition: Pure Zn 2nd premelt pot composition: 2wt%Aj2-Zn Hopper storage: Pb grains (average particle size 5+nm) Plating conditions Plate thickness: 0.7mm Plate width: 1200mm Line speed: 120 m/min Plating deposition amount (one side): 90 g/rn” Calculating from these plating conditions, the A℃ concentration to be replenished is 0.6 wt%,
The reduction amount of the plating bath is 30 g/min. The supply form from the pre-melt pot to the plating bath was as follows: pure Zn was supplied from the first pre-melt pot at 21 kg/min, and 2 wt% A11-Zn alloy was supplied at 9 g/m from the second pre-melt pot.
It was continuously replenished at in. The conduit between each brimetal pot and the plating bath was heated to about 450-480° C. by a heater to prevent the molten metal from solidifying within the tube.

Further, the amount of decrease in pb is 0.2 g/hr.

The replenishment method is to supply PB grains from a hopper at a pitch of 5 hours.
Kg was replenished intermittently. The reason why PB is not refilled into the plating bath after being dissolved in a pre-melt pot is that the amount of PB reduced is very small, so if it is refilled with pre-melt, it will adhere to the inside of the conduit and the accuracy of the replenishment amount will deteriorate. This is because, as a result, the diameter of the conduit becomes smaller and coagulation becomes easier within the conduit.

(Comparative Example) The plating bath composition and plating conditions were the same as those in Inventive Example 1, and a 0.4 wt% Au-Zn alloy ingot weighing 1 ton was coated with 10 wt% A of 20 g at a pitch of about 33 minutes.
The f-Zn alloy ingot was intermittently introduced into the plating bath at intervals of about 8 hours to replenish the components.

For the above-mentioned Invention Examples 1.2.3 and Comparative Examples, changes over time in the AIt concentration in the plating were investigated. The results are shown in the graph of FIG. As is clear from this graph, Examples 1.2 and 3 of the present invention have a higher AJ than the Comparative Example. It was found that there was little variation in concentration, especially in Examples 2 and 3 of the present invention in which continuous replenishment was performed, there was almost no variation from the target value of Af concentration, and therefore the desired plating quality could be stably obtained. .

Further, the same holds true for the PB concentration in Rakuchu, and it was found that according to the PB replenishment mode of Example 3 of the present invention, concentration fluctuations were almost eliminated and the plating quality was stabilized.

<Effects of the Invention> According to the method for replenishing components to a plating bath of the present invention, the concentration and amount of replenishing components can be arbitrarily selected by replenishing components from a plurality of pre-melt pots or pre-melt pots and hoppers. Therefore, fluctuations in the concentration of components in the plating can be suppressed, and good plating quality can be stably obtained.

In particular, when determining the necessary replenishment concentration of components and the reduction amount of the plating bath from the plating conditions, it becomes possible to replenish the components more appropriately, and even if the plating conditions change, it is possible to respond to the changes. Therefore, it becomes possible to strictly control the concentration of components in plating.

[Brief explanation of the drawing]

1, 2, 3, 4 and 5 are lines schematically showing examples of the configuration of equipment for carrying out the method of replenishing ingredients to a hair bath of the present invention, respectively. FIG. FIG. 6 is a graph showing the relationship between the amount of plating deposited and the He1 concentration in the plating layer. FIG. 7 is a graph showing changes over time in the Aj2 concentration in the hair removal bath. Explanation of symbols 1...Muffing bath, 2... Molten metal for plating, 3... Zinc roll, 4... Correcting roll, 5... Stabilizing roll, 6... w4f, 7... Snout, 8.10... Pre-melt pot, 9... Molten Zn, 11... Molten Ab-Zn alloy, 12.14... Pump, 13.15... Conduit, 131.151...Inlet, 16...Spacer, 17...Compressor, 18...Hopper, 19...Blade, 20...Metal powder grain,

Claims (4)

[Claims] (1) In a method for replenishing components into a plating bath when performing hot-dip plating in a plating bath containing multiple components, multiple pre-melt pots in which replenishment components are melted in advance are used to determine the necessary replenishment concentration and A method for replenishing components into a plating bath, comprising replenishing components from the pre-melt pot to correspond to the reduced amount. (2) The method for replenishing components to a plating bath according to claim 1, wherein the necessary replenishment concentration and the amount of decrease in the plating bath are determined by plating conditions. (3) In a method for replenishing components into a plating bath when performing hot-dip plating in a plating bath containing multiple components, at least one pre-melt pot in which replenishment components are melted in advance and metal lumps or metal powder particles of replenishment components are used. A method for replenishing components into a plating bath, comprising using at least one hopper containing the pre-melt pot and replenishing components from the pre-melt pot and hopper to correspond to the required replenishment concentration and the reduction amount of the plating bath. (4) The method for replenishing components to a plating bath according to claim 3, wherein the necessary replenishment concentration and the amount of decrease in the plating bath are determined by plating conditions.