JPH08325789A - Equipment for production of electrogalvanized steel sheet having excellent lubricity - Google Patents

Abstract

PURPOSE: To continuously produce an electrogalvanized steel sheet having excellent press formability, etc., on an industrial scale by successively providing the above equipment with respective devices for pretreating of the steel sheet, electrogalvanizing, washing, forming of oxidized films for improving lubricity and drying. CONSTITUTION: This equipment is successive provided with the device 1 for pretreating the steel sheet, the electrogalvanizing device 3, the washing device 4, the device 5 for forming the oxide films for improving the lubricity and the drying device 6. For example, a steel strip 2 is introduced into the device 1 for pretreating the steel sheet where the steel strip 2 is cleaned by removing the rolling mill lubricants, oxide, etc., from its surface. The steel strip is thereafter introduced into the electrogalvanizing device 3 and is subjected to electrogalvanizing, by which the electrogalvanized steel strip is obtd. This steel strip is then introduced into the washing device 4 consisting of a tank filled with washing water and is washed and thereafter, the steel strip is introduced into the device 5 for forming the oxidized films for improving the lubricity where the oxidized films for improving the lubricity are formed. The moisture in the oxidized films for improving the lubricity are thereafter removed in the drying device 6 and a simple rust preventive oil is applied on the steel strip. The steel strip is then taken up like a coil, by which the product is obtd. An activation treating device may be installed behind the washing device 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facility for producing electrogalvanized steel sheets having excellent lubricity.

[0002]

2. Description of the Related Art Mn,
JP-A-4-88176 discloses that P oxide or the like is generated to improve lubricity (pressability) and chemical conversion treatability. Such surface-treated steel sheet has improved press formability as compared with cold-rolled steel sheet, has no flaws during forming, and has no oxide peeling due to pressing, and has excellent chemical conversion treatability. It is a thing.

[0003]

As described above, the electrogalvanized steel sheet is excellent in lubricity and chemical conversion treatability,
The fact is that the motives adopted by automobile manufacturers, home appliance manufacturers, etc. are increasing. However, when it is adopted (used) by automobile manufacturers, it is necessary to stably supply a large amount of high-quality electrogalvanized steel sheets with excellent lubricity, etc., as the amount used will be enormous. It is clear that However, as described above, the electrogalvanized steel sheet excellent in lubricity and the like is a new product, and there is no facility to stably manufacture it on an industrial scale. There are problems such as being unable to supply. The present invention has been made in order to advantageously solve such a problem, and to provide a facility for stably producing an electrogalvanized steel sheet having excellent lubricity and the like as described above on an industrial scale. It is intended.

[0004]

A feature of the present invention resides in that a steel sheet pretreatment device, an electrogalvanizing plating device, a cleaning device, an oxide film forming device for improving lubricity, and a drying device are connected in series. A facility for manufacturing electrogalvanized steel sheets with excellent lubricity, which is characterized by And a steel plate pretreatment device, an electric zinc-based plating device, a cleaning device, an activation treatment device, an oxide film generation device for improving lubricity, and a drying device, which are excellent in lubricity. This is a facility for manufacturing electrogalvanized steel sheets.

[0005]

As the steel plate pretreatment device, it is preferable to continuously guide the steel strip (steel plate) to the steel plate pretreatment device and wash it with an alkaline aqueous solution having a pH of 10 or more, such as sodium orthosilicate, sodium tannate, and caustic soda. When the pH is less than about 10, the oxides generated on the surface of the zinc-plated steel sheet may be insufficiently removed, and it may take a long time to remove the oxides, which may affect productivity. Absent.
It can be cleaned by immersing the electrogalvanized steel sheet in such an alkaline aqueous solution or by electrolytic treatment in the alkaline aqueous solution. In addition, washing with an acidic aqueous solution of hydrochloric acid, sulfuric acid or the like as described above.

As described above, the washed steel strip is guided to the electrogalvanizing apparatus, and the vertical or horizontal electroplating apparatus uses the steel strip as the cathode and the electrode as the anode to energize in the electroplating solution to perform galvanizing. Is to be applied. The electrogalvanized steel sheet includes, for example, aluminum containing zinc as a main component, and the plating composition includes pure Zn, Zn and Fe, Zn and Ni, Zn and Al, Zn and Mn, and Zn and C.
With Zn, such as r, Zn and Ti, Zn and Mg as a main component,
Or to improve various functions such as corrosion resistance, Fe, Ni, C
o, Al, Pb, Sn, Sb, Cu, Ti, Si, B,
It contains one or more alloying elements such as P, N, S, and O and impurity elements, fine particles of ceramics such as SiO ₂ , Al ₂ O ₃ , oxides such as TiO ₂ and BaCrO ₄ , acrylic resin, etc. There are those in which the organic polymer of is dispersed in the plating layer, there are those of single composition in the thickness direction of the plating layer, those of which composition changes continuously or in a layered manner
Further, in the multi-layer plated steel sheet, in addition to pure Zn as the plating composition, Zn and Fe, Zn and Ni, Zn and Al are added to the uppermost layer.
Zn and Mn, Zn and Cr, Zn and Ti, Zn and Mg, etc., containing Zn as a main component, and one or more alloy elements and impurity elements for improving various functions such as corrosion resistance,
In addition, ceramic fine particles such as SiO ₂ and Al ₂ O ₃ ,
There are those in which an oxide such as TiO ₂ or BaCrO ₄ or an organic polymer such as an acrylic resin is dispersed in the plating layer.
The coating weight is 0.5 to 100 g / m ² and can be applied to a wide range of applications.

[0007] The galvanized steel strip thus electrogalvanized is used as a cleaning device, for example, a cleaning water sprinkler,
After introducing the tank to a tank filled with cleaning water and removing the plating solution and the like by cleaning, an oxide film for improving lubricity is generated to improve lubricity and the like.

On the surface of the electrogalvanized steel sheet that has been washed as described above, an oxide film of a plating layer alloy element such as zinc or aluminum is formed, and even if such a film is formed, oxidation for improving lubricity is formed. An inorganic oxide film can be formed as a film, and pressability and chemical conversion treatment are improved. However, the adhesive strength of the adhesive is the same as when an inorganic oxide film is formed on a plated steel sheet on which an oxide film of a plating layer alloy element such as zinc or aluminum is formed, or when an oxide such as zinc or aluminum is formed. It was found that the latter is remarkably superior in the case where the inorganic oxide film is formed on the surface which is not formed. The reason for this is not clear, but it is estimated as follows. When the inorganic oxide film is formed on the surface where the oxide such as zinc or aluminum is not formed, the plating layer surface is uniformly etched to form the film when the inorganic oxide film is formed, Adhesion between the plating layer and the coating becomes good. However, when an inorganic oxide film is formed on the surface where an oxide film such as zinc or aluminum is formed, the inorganic oxide film is thin, and after the plating layer is etched in the non-formed part, the oxide film It is formed uniformly on the surface of the film. Therefore, the pressability depends on the coating effect of this inorganic oxide film, and therefore the chemical conversion treatability is completely dissolved in the chemical conversion treatment liquid for both the oxide film and the oxide film, and the formation of the chemical conversion treatment film becomes possible, resulting in a difference in effect. However, it is considered that the adhesive strength of the adhesive decreases because the bonding force between the oxide film and the inorganic oxide film cannot be secured.

That is, in the present invention, in order to further improve the lubricity of the electrogalvanized steel sheet after the formation of the inorganic oxide film, the decrease in the film binding force between the oxide film and the inorganic oxide film is avoided. In order to do so, it is preferable that the electrogalvanized steel sheet after cleaning is guided to an activation treatment device to activate the surface of the plated steel sheet as described above.

In the activation treatment apparatus as described above, it is possible to avoid a decrease in the film binding force between the oxide film formed on the surface of the electrogalvanized steel sheet and the inorganic oxide film. As described above, by forming an inorganic oxide film, the plating layer is etched to be integrated with Zn or an oxide or hydroxide of a plating layer alloy element supplied to the film. As the activation method, there are a method of washing with an alkaline aqueous solution, a method of washing with an acidic aqueous solution, and a method of brushing such as grinding.

As described above, the electrogalvanized steel strip after cleaning or activation is guided to an oxide film generator for improving lubricity, and as an oxide film for improving lubricity on the surface of the plated steel sheet, for example, Mn, Mo, P, One or two of Co, Ca, Ni, W, V, B
An inorganic oxide composed of one or more species is produced. Such an oxide forms a glassy film similar to the chromate film, and suppresses galling of the plating on the die at the time of pressing to improve the slidability. Further, unlike the chromate film, it completely dissolves in the chemical conversion treatment liquid to form a uniform chemical conversion treatment film, and these components are also components of the chemical conversion treatment liquid and do not contaminate the chemical conversion treatment liquid. The structure of such an inorganic oxide is Mn, Mo, Co, Ca, Ni, W, V and Zn or an oxide or hydroxide of a plating layer alloy element supplied to the film by etching the plating layer, It is thought to be a complex of phosphate, sulfate, nitrate, borate, etc., Mn-O bond, other metal-O
Bond, P -O bond, in the network entity comprising a B -O bond, partially -OH, CO ₃ group etc., more amorphous macromolecular structure der metal supplied has been substituted from the plating layer I presume to be. In addition, since such oxides do not dissolve in the washing process with oil and the degreasing process,
Deterioration of lubrication performance during pressing and almost no load on other processes.

The formation of such an oxide on the electrogalvanized steel sheet can be achieved by, for example, immersing the galvanized steel sheet in an aqueous solution, spraying the aqueous solution, or the like, and surely producing it by electrolytic treatment. it can. At this time, the alloy elements (metals) of the zinc-plated steel sheet and impurities in the aqueous solution are slightly mixed in the oxide, but this is not an obstacle. The elements that do not hinder the inclusion of Li in the film are Li, Be, C, F, Na, Mg, Al, Si, Cl, K, Ca, N.
i, Mo, V, W, Ti, Fe, Rb, Sr, Y, Zn, Nb, Cs, B
a, Ions and oxides of lanthanides, hydroxides, phosphates, sulfates, nitrates, etc. will not affect even if mixed to some extent (about 10% or less in the film). In addition, Cr, Cd, Pb, Sn, As
If the amount is a trace amount, the chemical conversion treatment property and the contamination of the chemical conversion treatment liquid are not affected, and the effect remains unchanged.

Next, the production range of the inorganic oxide is
The amount of metal should be 1 mg / m ^2, but if it exceeds 500 mg / m ² , it is not preferable because the dissolution of the coating becomes slow and the formation of the chemical conversion coating becomes unstable in the chemical conversion treatment performed by users of automobiles and home appliances. Therefore, 1 to 500 mg / m ² , preferably 1
~ 200 mg / m ² .

As the method for producing the above-mentioned inorganic oxide, for example, as the Mn-based oxide, potassium permanganate, phosphoric acid, sodium borate, ammonium molybdate, phosphomolybdic acid, ammonium tungstate, phosphotungsten is used. As a chloride, sulfate or phosphate of acid, silicotungstic acid, ammonium vanadate, cobalt, nickel, calcium, etc., from 1 g / l to the solubility limit, phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, in order to accelerate the reaction,
A bath to which a fluoride or the like is added can be used.

In this way, after the oxide film for improving lubricity is formed on the surface of the plated steel sheet, the oxide film is introduced into a drying device, and the moisture in the oxide film is removed by contact with hot air, electric heat, or a heating roll. is there. In some cases, after the oxide film for improving lubricity is formed, a cleaning device is provided prior to drying,
It can also be washed by washing with water or hot water.

As described above, by aging the formed inorganic oxide, a dehydration condensation reaction (crosslinking reaction) and a reduction reaction of the compound with the inorganic oxide occur at the same time, and the oxide is difficult to be neutral or alkaline. Since it is reduced to solubility, it is possible to reliably suppress the elution of oxides into the liquid during the degreasing process after pressing, thus suppressing the contamination of the degreasing liquid due to the elution of oxides, the life of the degreasing liquid and the load of wastewater treatment. Can be reduced. As the aging method, the above-mentioned inorganic oxide can be certainly aged by heating and holding it during the drying. That is, it can be aged by sufficiently removing the water content in the inorganic oxide, and can be aged.
It can be matured in 48 hours. Such an aging treatment is not necessary for aging since the heterogeneous oxide is washed off on the surface of the inorganic oxide when the inorganic oxide is washed (rinsed) after the inorganic oxide is produced. When the washing (rinsing) after the production of the system oxide is omitted, the heterogeneous oxide remains and it is preferable to age it. Therefore, whether to keep it dry or to ripen it depends on the necessity. In addition, as described above, by providing a post-treatment device such as a chromate device and an organic film coating device next to the drying device, the post-treatment can be performed in the same equipment, which can enhance productivity and the like, which is extremely preferable. .

[0017]

EXAMPLES Next, examples of the present invention will be described. Example 1 In FIG. 1, a steel strip (plate) 2 is introduced to a steel plate pretreatment device 1, and rolling oil, oxides, etc. on the surface of the steel strip 2 are removed and cleaned, and then introduced into an electrogalvanizing plating device 3. Then, electrogalvanized plating is performed to form electrogalvanized steel strip 2. Then, it is guided to a cleaning device 4 composed of a tank filled with cleaning water, the plated steel strip 2 is cleaned, and then an oxide film for improving lubricity is formed. Device 5
To produce an oxide film for improving lubricity, after which the moisture in the oxide film for improving lubricity is removed by the drying device 6, and simple rust preventive oil is applied to form a coiled product. Example 2 In FIG. 1, a steel strip (plate) 2 is guided to a steel plate pretreatment device 1, and rolling oil, oxides, etc. on the surface of the steel strip 2 are removed and cleaned, and then introduced into an electrogalvanizing plating device 3. Then, electrozinc-based plating is performed to form electrozinc-based plated steel strip 2. Then, it is guided to a cleaning device 4 composed of a tank filled with cleaning water, and after cleaning the plated steel strip 2, it is guided to an activation device 7 and plated. After the oxide on the surface of the steel strip 2 is removed and activated, it is led to the lubricity improving oxide film generating device 5 to generate a lubricity improving oxide film. Water is removed, simple rust preventive oil is applied, and the product is coiled into a coiled product.

[0018]

According to the present invention, an oxide film for improving lubricity, which is excellent in pressability and chemical conversion treatability, can be continuously and stably formed on an electrogalvanized steel strip (plate). Since it is possible to mass-produce an electrogalvanized steel strip (plate) excellent in pressability and chemical conversion treatability on a dynamic scale, a large industrial effect can be achieved.

[Brief description of drawings]

FIG. 1 is a flow chart showing an embodiment of the present invention.

FIG. 2 is a flow chart showing an embodiment of the present invention.

[Explanation of symbols]

 1 Steel Plate Pretreatment Device 3 Electrogalvanized Plating Device 4 Cleaning Device 5 Oxide Film Generation Device for Lubrication Improvement 6 Drying Device 7 Activation Device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Ogawa 5-3 Tokai-cho, Tokai-shi, Aichi Nippon Steel Co., Ltd. Inside the Nagoya Works

Claims (2)

[Claims] 1. An electric zinc excellent in lubricity, comprising a steel sheet pretreatment device, an electrogalvanic plating device, a cleaning device, an oxide film forming device for improving lubricity, and a drying device, which are connected in series. Equipment for producing galvanized steel sheets. 2. A lubrication characterized in that a steel sheet pretreatment device, an electrogalvanized plating device, a cleaning device, an activation treatment device, an oxide film generation device for improving lubricity, and a drying device are connected in series. Equipment for manufacturing electrogalvanized steel sheets with excellent properties.