JPH09143660A - Production of galvanized steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further form a film excellent in press formability, spot weldability, and adhesion on the surface of a plating layer of a galvanized steel sheet. SOLUTION: A galvanized steel sheet is immersed in an aqueous solution of 20-70 deg.C and pH1.0-3.5, which contains either or both of ferrous sulfate and ferrous nitrate and either or both of Ni sulfate and Ni nitrate and in which the sum of Fe content and Ni content is regulated to (0.1 to 3.0)mol/l and also the ratio of Fe content (mol/l) to the sum of Fe content (mol/l) and Ni content (mol/l) is regulated to 0.004-0.9. By this procedure, an Fe-Ni-O film is formed on the surface of the plating layer of the galvanized steel sheet.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a zinc-based plated steel sheet, and more particularly to a method for producing a zinc-based plated steel sheet having excellent press formability, spot weldability and adhesiveness.

[0002]

2. Description of the Related Art Galvanized steel sheets are widely used as various kinds of rust-proof steel sheets because they have various excellent characteristics. In order to use this galvanized steel sheet as an anti-corrosion steel sheet for automobiles, in addition to corrosion resistance, paint compatibility, etc., it is required to have excellent press formability, spot weldability and adhesion as the performance required in the body manufacturing process. It is important that

However, zinc-based plated steel sheets generally have a drawback that they are inferior in press formability to cold-rolled steel sheets. This is because the sliding resistance between the zinc-based plated steel sheet and the press die is higher than that in the case of cold-rolled steel sheet.If this sliding resistance is high, near the bead part of the die during pressing. It becomes difficult for the galvanized steel sheet to flow into the press die, and the steel sheet easily breaks.

As a method of improving the press formability of a zinc-based plated steel sheet, a method of applying a high-viscosity lubricating oil is generally widely used. However, in this method, since the lubricating oil has a high viscosity, there are problems such as a coating defect due to poor degreasing in the next coating step, and oil depletion, which causes unstable press performance. There is a high demand for improvement in press formability of galvanized steel sheets.

On the other hand, in a zinc-based plated steel sheet, copper, which is an electrode, reacts with molten zinc during spot welding to easily form a brittle alloy layer, so that the copper electrode is greatly worn and its life is short. There is a problem that continuous hot spotting properties are inferior to cold rolled steel sheets.

Further, in the manufacturing process of an automobile body,
Although various adhesives are used for the purpose of rust prevention and vibration control, it has recently become clear that zinc-based plated steel sheets are inferior in adhesiveness to cold-rolled steel sheets.

As a method for solving the above problem, Japanese Patent Laid-Open No.
JP-A-190483 discloses that an electrolytic film, a dipping process, a coating oxidation process, or a heating process is performed on the surface of a zinc-based plated steel sheet to generate an oxide film mainly composed of ZnO, thereby improving weldability or workability. The technology (hereinafter, referred to as "prior art 1") is disclosed. Also, Japanese Patent Application Laid-Open No. 3-1
Japanese Patent No. 7282 discloses a method (hereinafter referred to as Prior Art 2) in which one or more metals selected from Fe, Ni and Co are substitutionally deposited on the surface of a zinc-based plated steel sheet. Japanese Unexamined Patent Publication No. 3-191093 discloses a technique of forming Ni oxide to improve press formability and chemical conversion treatability (hereinafter referred to as prior art 3).
Japanese Patent Laid-Open No. 60-63394 discloses a method for improving weldability by applying an aqueous solution of an inert film component (hereinafter referred to as prior art 4).

[0008]

The above-mentioned prior art 1 has the following problems. That is, Prior Art 1
Then, since it is a method of producing an oxide mainly composed of ZnO on the plating surface by various treatments, the effect of reducing the sliding resistance between the press die and the plated steel sheet is small, and the effect of improving press formability is small. small. Further, an oxide mainly composed of ZnO deteriorates the adhesiveness.

Prior art 2 has the following problems. With the method of depositing a metal such as Ni or Fe, sufficient adhesion cannot be obtained because the wettability of the metal with respect to the adhesive is small. In addition, there is a problem that the effect of improving press formability and spot weldability is small due to the strong metallic properties of the coating. Further, the pH of the aqueous solution is low and the substitution precipitation efficiency is low, so that a sufficient amount of adhesion cannot be secured, and the temperature of the aqueous solution needs to be raised to secure the amount of deposition, which causes an increase in energy consumption rate. However, there is a problem that the manufacturing cost is increased by installing a heating facility for the aqueous solution.

In the prior art 3, since it is a Ni oxide single-phase coating, the press formability is improved, but the adhesiveness is deteriorated.

In the prior art 4, since it is a method of forming an inactive film, there is a problem that the chemical conversion treatment property and the adhesive property are deteriorated.

Therefore, an object of the present invention is to solve the above-mentioned problems and provide a method for producing a zinc-based plated steel sheet which is excellent in press formability, spot weldability and adhesiveness.

[0013]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an appropriate Fe-Ni-O-based film is formed on the surface of the plating layer of a zinc-based plated steel sheet. It has been found that by forming, the press formability, spot weldability and adhesiveness can be improved.

The press formability of the zinc-based plated steel sheet is inferior to that of the cold-rolled steel sheet because the sliding resistance is high because the low melting point zinc and the die cause the adhesion phenomenon under high surface pressure. The cause is the increase. In order to prevent this, it is effective to form a film that is harder and has a higher melting point than the zinc or zinc alloy plating layer on the surface of the plating layer of the zinc-based plated steel sheet. The sliding resistance between the die and the die decreases, the zinc-based plated steel sheet easily slips into the press die, and the press formability improves. The Fe-Ni-O-based coating satisfies the above conditions.

The continuous spotting property in spot welding of a zinc-based plated steel sheet is inferior to that of a cold-rolled steel sheet because the molten zinc and the copper of the electrode come into contact with each other during welding to form a brittle alloy layer. In addition, the deterioration of the electrode becomes severe. Therefore, as a method for improving the continuous spotting property of a zinc-based plated steel sheet, it is considered effective to form a high melting point film on the plated surface. The present inventors have studied various coatings in order to improve the spot weldability of zinc-based plated steel sheets, and have found that a Ni oxide coating is particularly effective. The details of this reason are not clear,
The reason is that Ni reacts with Zn to form a high melting point Zn—Ni alloy, and that the Ni oxide has a very high melting point and that it has high electrical conductivity among various coatings due to its semiconducting properties. Conceivable.

It has been known that the adhesiveness of the zinc-based plated steel sheet is inferior to that of the cold rolled steel sheet, but the cause has not been clarified. Then, as a result of investigating the cause, the present inventors have revealed that the adhesiveness is controlled by the composition of the oxide film on the surface of the steel sheet. That is, in the case of a cold-rolled steel sheet, the oxide film on the steel sheet surface is mainly Fe oxide, whereas in the case of a zinc-based plated steel sheet, Zn oxide is mainly. The adhesiveness differs depending on the composition of this oxide film.
The adhesiveness was inferior to that of the oxide. Therefore, it becomes possible to improve the adhesiveness by forming a film containing Fe oxide on the surface of the zinc-based plated steel sheet as in the present invention.

As described above, it is possible to properly form the mixed film of the metals of Ni and Fe and the oxides of Ni and Fe, that is, the Fe-Ni-O-based film on the surface of the zinc-based plated steel sheet. It was found that a zinc-based plated steel sheet having excellent press formability, spot weldability and adhesiveness can be obtained. Here, the Fe-Ni-O-based coating has a microstructure and morphology of at least Ni and Fe metals,
In addition, it may be formed of a mixed film containing oxides of Ni and Fe, and the bonding state of the elements constituting the film does not matter. The present invention has been made based on the above findings, and by appropriately forming a Fe-Ni-O-based coating on the surface of the plating layer of a zinc-based plated steel sheet, press formability and spot weldability are obtained. And a method for producing a zinc-based plated steel sheet having excellent adhesiveness, which is as follows.

The method for producing a zinc-plated steel sheet according to the present invention comprises at least one of ferrous sulfate and ferrous nitrate,
Also, by immersing the zinc-based plated steel sheet in an aqueous solution containing at least one of nickel sulfate and nickel nitrate, when forming a film on the surface of the plating layer of the zinc-based plated steel sheet, the iron content in the aqueous solution (Mol
/ L) and the nickel content (mol / l) are 0.1
To 3.0, the iron content in the aqueous solution (mo
The ratio of the iron content (mol / l) to the sum of the nickel content (mol / l) is 0.004 to 0.
Fe-by immersing the zinc-based plated steel sheet in an aqueous solution having a pH of 1.0 to 3.5 and a temperature of 20 to 70 ° C. Ni
It is characterized by forming an -O-based film.

In this application, in the present invention and in the context of the present invention, a Fe-Ni-O-based coating as an upper layer formed on the surface of the plating layer of a zinc-based plated steel sheet is referred to as a "coating". On the other hand, when referring to zinc or a zinc-based plating layer as the lower layer, the term "plating layer" is used to distinguish between the two.

[0020]

Next, the reason for limiting the manufacturing conditions of the present invention as described above will be described. In the present invention, the surface of the plating layer of the zinc-based plated steel sheet is Fe-Ni-
FeSO ₄ and Fe to form an O-based film
(NO ₃₎ and at least one of the _two, the reason for immersing the zinc-plated steel sheet in an aqueous solution containing at least one of NiSO ₄ and Ni (NO _{3) 2} is, Fe into the liquid
Ions and Ni ions can be added in the form of various salts, but the solubility thereof is good, the problem of corrosiveness to equipment is small, the degree of adverse effects on the human body is small, and the economy is low. Considering that it is good, it should be added in the form of sulfate and / or nitrate.

As the means for forming the Fe-Ni-O-based coating, the same effect as the dipping method can be obtained by spraying a coating-forming aqueous solution or a roll coating method.
However, in the electroplating method, the film formed becomes metallic, and it is difficult to form the Fe-Ni-O-based film of the present invention, and it is difficult to obtain a film having good press formability and adhesiveness. . Further, the electroplating method and the vapor-phase plating method require enormous equipment costs, and the operating cost is high, which leads to an increase in manufacturing cost.

The reason that the sum of the iron content (mol / l) and the nickel content (mol / l) in the aqueous solution should be within the range of 0.1 to 3.0 is 0.1 mol / l. When it is less than 1.0, the precipitation rate of Ni and Fe decreases, which leads to a decrease in productivity. On the other hand, when it exceeds 3.0, the metal salt concentration reaches the solubility when the temperature is low and precipitation of the metal salt occurs. Is. Furthermore, the Fe content in the aqueous solution (mol /
The ratio of the Fe content (mol / l) to the sum of 1) and the Ni content (mol / l) should be within the range of 0.004 to 0.9 because Fe / (Fe + Ni) Is less than 0.004, there is no effect of improving the adhesiveness, while
This is because if it exceeds 0.9, the effect of improving spot weldability becomes small, which is not preferable.

The reason why the pH of the aqueous solution should be in the range of 1.0 to 3.5 is that when the pH is less than 1.0, the amount of hydrogen generated extremely increases and the precipitation efficiency of Ni and Fe decreases. However, under the same conditions of salt concentration and immersion time, the adhesion amount of Ni and Fe is small and the productivity is reduced. Furthermore, the coating mainly consists of Ni and Fe, and the effect of improving press formability, spot weldability, and adhesiveness cannot be obtained. On the other hand, when the pH exceeds 3.5, the oxygen content of the coating becomes high. Therefore, the effect of improving the weldability becomes small, and the chemical conversion processability deteriorates.

The reason why the temperature of the aqueous solution should be in the range of 20 to 70 ° C. is that the reaction rate is slow below 20 ° C.
Since it takes a long time to secure the amount of Ni and Fe deposited necessary for improving the characteristics of the coating, the productivity is lowered. On the other hand, when the temperature exceeds 70 ° C., the deterioration of the treatment performance of the aqueous solution is accelerated. This is because equipment and energy for keeping the temperature high are required, which causes an increase in manufacturing cost.

In the aqueous solution, Z contained in the plating layer of the zinc-based plated steel sheet used in the present invention, etc.
n, Co, Mn, Mo, Al, Ti, Sn, W, Si,
It may contain cations such as Pb, Nb and Ta, hydroxides and oxides, and may further contain anions other than sulfate ions and nitrate ions.

In the present invention, Fe-Ni-O is formed on the surface.
The zinc-based plated steel sheet used to form the system coating is a steel sheet that has a plated layer formed on the base steel sheet by methods such as hot dipping, electroplating and vapor phase plating. The composition of the zinc-based plating layer is pure zinc or F
e, Ni, Co, Mn, Cr, Al, Mo, Ti, S
Metals such as i, W, Sn, Pb, Nb and Ta (however,
Si is also treated as a metal) or an oxide, or a single-layer or multi-layer plating layer containing one or more of organic substances and the like. Further, the plating layer may contain fine particles such as SiO ₂ and Al ₂ O ₃ . Further, as the zinc-based plated steel sheet, a multi-layer plated steel sheet having a different composition of a plating layer and a functionally graded plated steel sheet can be used.

The Fe-Ni-O-based coating on the surface of the plating layer of the zinc-based plated steel sheet formed under the above-mentioned limited conditions eliminates the phenomenon of adhesion between the steel sheet and the mold during press forming and slides. Resistance is reduced, slipping into the mold is improved, formation of a brittle alloy layer with the electrode copper during spot welding is suppressed, and continuous spotting property is improved.
The action of the coating containing the e-oxide has the effect of improving the adhesiveness.

Here, the amount of the Fe-Ni-O-based coating adhered is 10 to 150 in terms of the total conversion amount of metal elements in the coating.
It is preferably within the range of 0 mg / m ² . If the total conversion amount is less than 10 mg / m ² , the effect of improving press moldability cannot be obtained, while if it exceeds 1500 mg / m ² ,
This is because the chemical conversion processability deteriorates. In order to adjust the amount of adhesion within such a desirable range, the immersion time should be adjusted in the case of an aqueous solution having the same salt concentration, and if the immersion time must be kept constant due to equipment restrictions such as equipment capacity. The method of adjusting the salt concentration of the aqueous solution and finely adjusting the pH and the temperature may be appropriately performed.

The oxygen content of the Fe-Ni-O-based coating is 0.5-10 wt. It is desirable to be within the range of%. The oxygen content is 0.5 wt. If it is less than 10% by weight, the metallic properties of the coating are strongly manifested, so that the effect of improving the press formability and spot weldability becomes small, while 10 wt. %
If it exceeds, the amount of the oxide becomes too large, resulting in an increase in the electric resistance of the surface, a decrease in the weldability, and the suppression of the formation of phosphate crystals, which deteriorates the chemical conversion treatability.

Further, the Fe content (wt.%) Relative to the sum of the Fe content and the Ni content in this film (wt.%)
Ratio (hereinafter, also referred to as "Fe ratio in the film", "Fe
/ (Fe + Ni) "is 0.004 to 0.9
It is desirable that it is within the range of 0.1 to 0.5, and especially within the range of 0.1 to 0.5. When Fe is contained in the coating, the adhesiveness is improved, but when Fe / (Fe + Ni) in the coating is less than 0.004, the effect of improving the adhesiveness is not exhibited. On the other hand, when Fe / (Fe + Ni) in the coating exceeds 0.9, the Ni content in the coating decreases, and the proportion of the high melting point Zn-Ni alloy formed during welding decreases, resulting in deterioration of the electrode. Is more intense and the effect of improving spot weldability becomes smaller.

[0031]

Next, the present invention will be further described with reference to examples. First, as the zinc-based plated steel sheet before the immersion treatment by the method of the present invention and the comparative method, the following GA, GI, E
G, Zn-Fe, Zn-Ni, Zn-Cr and Zn-
One in which any one of the plating species of Al was formed was used. GA: 10 wt. An alloyed hot-dip galvanized layer consisting of% Fe and the balance Zn is formed, and the adhesion amount is 60 g / m ² on both surfaces. GI: A hot-dip galvanized layer is formed, and the adhesion amount is 90 g / m ² on both sides. EG: An electrogalvanized layer was formed, and the adhesion amount was 40 g / m ² on both sides. Zn-Fe: 15 wt. An electric Zn-Fe alloy plating layer of% Fe is formed, and the adhesion amount is 40 g / m ² on both surfaces. Zn-Ni: 12 wt. An electric Zn-Ni alloy plating layer of% Ni is formed, and the deposition amount is 30 g / m ² on both surfaces. Zn-Cr: 4 wt. An electric Zn-Cr alloy plating layer of% Cr is formed, and the adhesion amount is 20 g / m ² on both sides. Zn-Al: 5 wt. % Al Al hot-dip Zn-Al alloy plating is formed, and the deposition amount is 60 g / m ² on both sides.

Examples were obtained by treating the above zinc-based plated steel sheet under the production conditions within the scope of the present invention and the production conditions outside the scope of the present invention shown in Treatment Nos. 1 to 35 in Tables 1 and 2. And the comparative example was implemented. Then, the specimen No. was given to the specimen determined by the combination of the treatment conditions (treatment Nos. 1 to 35) and the zinc-based plated steel sheet having the plating species (the above 7 species). Specimens used in Examples No. 1 to 7
5 and Comparative Examples No. 1 to 31.

[0033]

[Table 1]

[0034]

[Table 2]

Tables 3 to 7 show that Fe- formed on each specimen.
The property test of the Ni—O-based film and the property test of each specimen were performed, and the results are shown.

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

[Table 5]

[0039]

[Table 6]

[0040]

[Table 7]

As a property test of the Fe-Ni-O-based coating formed on each test piece, the adhesion amount (m
g / m ² ), the ratio of Fe content (wt.%) to the sum of Fe content (wt.%) and Ni content (wt.%) in the film (Fe / (Fe + Ni)), and The oxygen content (wt.%) Of the film was measured as follows.

[Amount of metal attached to the coating, and
Measurement of Fe / (Fe + Ni) in coating] Plating type is G
For the specimens of I, EG, Zn-Cr, and Zn-Al, the Fe-Ni-O-based coating was dissolved and peeled off with dilute hydrochloric acid together with the surface layer portion of the lower zinc-based plating layer, and Fe, Ni and metal were formed by the ICP method. The quantitative analysis of was performed to measure the total metal-equivalent deposition amount of the Fe—Ni—O-based coating and the composition of the coating. Then, Fe / (Fe
+ Ni) was calculated.

The plating species are GA, Zn-Fe, Zn-N
For the test sample of i, Fe-N
Since the i-O-based coating contains the constituent elements, it is difficult to completely separate the upper Fe-Ni-O-based coating constituent element and the lower-layer plated coating constituent element by the ICP method. Therefore, only the component elements of the Fe-Ni-O-based coating which were not contained in the lower plated coating were quantitatively analyzed by the ICP method. Further, after Ar ion sputtering, the composition distribution of each component element with respect to the depth in the plating film was measured by repeating the measurement of each component element in the Fe-Ni-O-based coating from the coating surface by the XPS method. In this measuring method, Fe-Ni which is not contained in the lower plated film is used.
The distance between the depth at which the constituent element of the -O-based film has the maximum concentration and the position at which the element is no longer detected is half the depth.
The thickness of the Fe-Ni-O-based film was used. Then, from the results of the ICP method and the results of the XPS method, the total metal-equivalent deposition amount of the Fe—Ni—O-based coating and the composition of the coating were measured.
Next, Fe / (Fe + Ni) in the film was calculated.

[Measurement of Oxygen Content of Coating] The oxygen content of the coating was determined from the depth direction analysis result of Auger electron spectroscopy (AES).

Next, as a characteristic test for each of the samples of Examples and Comparative Examples, press formability, continuous spotting property in spot welding, adhesiveness and chemical conversion treatability were tested by the following methods.

[Measurement of Friction Coefficient] In order to evaluate press formability, the friction coefficient was measured by the following method. FIG.
It is a schematic front view which shows a friction coefficient measuring device. As shown in the figure, a friction coefficient measuring sample 1 collected from a specimen is fixed to a sample table 2, and the sample table 2 is fixed to an upper surface of a horizontally movable slide table 3. On the lower surface of the slide table 3, there is provided a vertically movable slide table support 5 having a roller 4 in contact with the slide table 3, and by pushing up the slide table support 5, a sample for measuring a friction coefficient by a bead 6 is provided. 1st load cell 7 for measuring the pressing load N to 1
Are mounted on the slide table supporting base 5. With the pressing force applied, a second end for measuring the sliding resistance F for moving the slide table 3 in the horizontal direction is provided at one end of the slide table 3 in the horizontal movement direction. A load cell 8 is attached to one end of the slide table 3. A test cleaning oil Preton R352L manufactured by Sugimura Chemical Co., Ltd. was used as a lubricating oil and was applied to the surface of the friction coefficient measurement sample 1 for the test.

The coefficient of friction μ between the specimen and the bead is
Formula: Calculated by μ = F / N. However, pressing load N: 400
kgf, sample withdrawing speed (horizontal moving speed of slide table 3): 100 cm / min.

FIG. 2 is a schematic perspective view showing the shape and dimensions of the beads used. The lower surface of the bead 6 slides while being pressed against the surface of the sample 1. The underside shape is width 1
0 mm, a flat surface having a length of 3 mm in the sliding direction, and each of the front and rear surfaces having a width of 10 mm having a diameter of 4.5 mmR.
The / 4 cylindrical surface is in contact as shown in FIG.

[Continuous RBI Test] In order to evaluate the spot weldability, a continuous RBI test was conducted on each test piece. Resistance welding (spot welding), in which two specimens of the same No. were stacked, sandwiched by a pair of electrode tips from both sides, and current was concentrated by applying pressure, was continuously performed under the following welding conditions. .・ Electrode tip: dome type with a tip diameter of 6 mm ・ Pressure force: 250 kgf ・ Welding time: 12 cycles (60 Hz) ・ Welding current: 11.0 KA ・ Welding speed: 1 point / sec. As the evaluation of continuous spotting property, during spot welding, the diameter of the melted and solidified metal part (shape: go-stone, hereafter referred to as nugget) generated at the joint of two welded base materials (specimen) was 4 The number of spots continuously welded until it became less than × t ^1/2 (t: plate thickness of one sheet) was used.

[Adhesiveness Test] The following adhesiveness test specimens were prepared from the respective specimens. FIG. 3 is a schematic perspective view illustrating the assembling process. As shown in FIG.
Specimen 13 in which two test pieces 10 having a length of m and a length of 200 mm are stacked and adhered so that the thickness of the adhesive 12 is 0.15 mm with a spacer 11 having a diameter of 0.15 mm therebetween.
And baking at 150 ° C. × 10 min. The specimen thus prepared was bent into a T-shape as shown in FIG.
A tensile test was performed at a speed of / min to measure the average peel strength (n = 3 times) when the test body peeled. The peel strength was determined by calculating the average load from the load chart of the tensile load curve at the time of peeling, and expressed in units of kgf / 25 mm. In FIG. 4, P indicates a tensile load. The adhesive used was a PVC-based hemming adhesive.

[Chemical conversion treatability test] In order to evaluate the chemical conversion treatability, the following test was conducted. Each test piece was treated with an immersion type zinc phosphate treatment solution (PBL3080 manufactured by Nippon Parkerizing Co., Ltd.) for an automobile coating base under ordinary conditions to form a zinc phosphate film on the surface thereof. The crystalline state of the zinc phosphate film formed in this way is examined by a scanning electron microscope (SE
M). As a result, the case where the zinc phosphate film was normally formed was represented by ◯, and the case where the zinc phosphate film was not formed or the crystal had a scale was represented by x.

The friction coefficient, the number of continuous spots, the peel strength and the chemical conversion treatment result of each test piece measured by the above-mentioned test method are shown in Tables 3 to 7 above.

The following are clear from Tables 3-7. Regarding the characteristics (press formability, spot weldability, and adhesiveness) of each sample, when the example and the comparative example are compared, in the same plating species, the example does not form a Fe-Ni-O-based film. Comparative Example (Specimen No. 1A; 1B; 1
C; 1D; 1E; 1F and 1G) in all of the above properties, and F under conditions outside the scope of the invention.
Comparative examples (2A, 3A, e-Ni-O based film formed)
13A, 14A, 15A, 16A, 23A, 24A, 2
5A, 26A; 2B, 13B; 2C, 13C; 2D, 1
3D; 2E, 13E; 2F, 13F; 2G, 13G) in at least one property, and the properties of the examples are generally excellent.

In Comparative Examples (32A, 33A) in which the temperature of the treatment aqueous solution was raised outside the range of the present invention, the respective characteristics were excellent, but the manufacturing cost increased.

[0055]

The present invention is configured as described above.
Fe- formed on the surface of the plating layer of zinc-based plated steel sheet
Since the Ni-O based coating is harder and has a higher melting point than the zinc or zinc alloy plated layer, the sliding resistance between the plated layer surface and the press die during press forming of the zinc based plated steel sheet is reduced. However, the zinc-based plated steel sheet easily slips into the press die, and the press formability is improved. Also, Fe
The presence of the —Ni—O-based high melting point film improves the continuous spotting property in spot welding. Furthermore, Fe-Ni-O
The presence of Fe oxide in the system coating improves the peel strength of the adhesive plate. Therefore, according to the present invention, press formability,
It is possible to provide a zinc-based plated steel sheet having excellent spot weldability and adhesiveness, which brings about an extremely useful effect industrially.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a friction coefficient measuring device.

FIG. 2 is a schematic perspective view showing the shape and dimensions of the bead in FIG.

FIG. 3 is a schematic perspective view illustrating an assembly process of an adhesiveness test specimen.

FIG. 4 is a schematic perspective view illustrating a load of a tensile load when a peel strength is measured in an adhesion test.

[Explanation of symbols]

 1 sample for friction coefficient measurement, 2 sample stage, 3 slide table, 4 roller, 5 slide table support, 6 beads, 7 first load cell, 8 second load cell, 9 rail 10 specimens, 11 spacers, 12 adhesives, 13 adhesion test specimens, P tensile load, F sliding resistance, N pressing load.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Inagaki 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Masaaki Yamashita 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Date Main Steel Pipe Co., Ltd.

Claims (1)

[Claims] 1. A zinc-based plated steel sheet is obtained by immersing a zinc-based plated steel sheet in an aqueous solution containing at least one of ferrous sulfate and ferrous nitrate, and at least one of nickel sulfate and nickel nitrate. In the method for producing a zinc-based plated steel sheet, which comprises forming a film on the surface of a plated layer of the steel sheet, the iron content (mol
/ L) and the nickel content (mol / l) are 0.1
To 3.0 mol / l, and the iron content (mol / l) and nickel content (mol / l) in the aqueous solution
The ratio of the iron content (mol / l) to the sum of
It is in the range of 0.004 to 0.9 and the pH is 1.0 to
Fe-Ni-O-based coating is formed by immersing the zinc-based plated steel sheet in the aqueous solution in the range of 3.5 and the temperature in the range of 20 to 70 ° C. And a method for manufacturing a zinc-plated steel sheet.