JP3191635B2 - Galvanized steel sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a galvanized steel sheet, and more particularly to at least excellent press formability among press formability, spot weldability, adhesiveness and chemical conversion treatment. The present invention relates to a galvanized steel sheet having excellent spot weldability, adhesiveness, and chemical conversion treatment properties as appropriate for the intended use.

[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 a rust-proof steel sheet for automobiles, in addition to corrosion resistance and paint compatibility, the performance required in the vehicle body manufacturing process includes press formability, spot weldability, adhesiveness and chemical conversion. It is important that the processability is excellent.

[0003] However, galvanized steel sheets generally have a drawback that press formability is inferior to cold-rolled steel sheets. This is because the sliding resistance between the galvanized steel sheet and the press die is greater than that of the cold rolled steel sheet. That is, since the sliding resistance is large, the zinc-plated steel sheet hardly flows into the press die in a portion where the sliding resistance between the bead and the galvanized steel sheet is extremely large, and the steel sheet is easily broken.

[0004] As a method for 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, there are problems such as the occurrence of coating defects due to poor degreasing in the coating process due to the high viscosity of the lubricating oil, and the unstable press performance due to running out of oil during pressing. Accordingly, there is a strong demand for improving the press formability of a zinc-based plated steel sheet.

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

Further, in the manufacturing process of an automobile body,
Various types of adhesives are used for the purpose of rust prevention and vibration damping of car bodies, but in recent years it has become clear that the adhesion of galvanized steel sheets is inferior to that of cold rolled steel sheets. Was.

As a method for solving the above-mentioned problems, Japanese Patent Application Laid-Open No. Sho 53-60332 and Japanese Patent Application Laid-Open No. Hei 2-19048 are known.
No. 3 discloses that an electrolytic film, an immersion treatment, a coating oxidation treatment, or a heat treatment is applied to the surface of a galvanized steel sheet to generate an oxide film mainly composed of ZnO, thereby improving weldability or workability. A technology (hereinafter, referred to as prior art 1) is disclosed.

JP-A-4-88196 discloses that a galvanized steel sheet is immersed in an aqueous solution of pH 2 to 6 containing 5 to 60 g / l of sodium phosphate on the surface of a galvanized steel sheet,
Electrolytic treatment and spraying of the above aqueous solution provide P
A technique for forming an oxide film mainly composed of an oxide to improve press formability and chemical conversion treatment (hereinafter referred to as prior art 2) is disclosed.

[0009] Japanese Patent Application Laid-Open No. Hei 3-191093 discloses a press-forming property and a chemical conversion treatment by forming Ni oxide on the surface of a galvanized steel sheet by electrolytic treatment, dipping treatment, coating treatment, coating oxidation treatment or heating treatment. A technique for improving the performance (hereinafter referred to as Prior Art 3) is disclosed.

Japanese Patent Application Laid-Open No. 58-67785 discloses a technique for improving the corrosion resistance by generating metals such as Ni and Fe by, for example, but not limited to, electroplating or chemical plating on the surface of a galvanized steel sheet. Hereinafter, Prior Art 4
Is disclosed).

[0011]

However, the above-mentioned prior art has the following problems. Prior art 1 is a method of generating an oxide mainly composed of ZnO on the surface of a plating layer by the above-described various processes, so that ordinary weldability and workability are improved. There is a problem that the effect of reducing the sliding resistance is small, the effect of improving the press formability is small, and if an oxide film mainly composed of ZnO is present on the plating surface, the adhesion is deteriorated.

The prior art 2 is a method of forming an oxide film mainly composed of P oxide on the surface of a zinc-based plated steel sheet. There is a problem that the adhesiveness is deteriorated.

Prior art 3 is a method of forming a single-phase Ni oxide film, so that press formability is improved.
On the other hand, there is a problem that the adhesiveness is reduced.

Prior art 4 is a method of producing only a metal such as Ni, so that the corrosion resistance is improved. However, since the metallic properties of the film are strong, the effect of improving press formability and spot weldability is not sufficient. Furthermore, there is a problem that the wettability of the metal with respect to the adhesive is low and sufficient adhesiveness cannot be obtained.

Accordingly, an object of the present invention is to solve the above-mentioned problems, to provide a basic condition that the sliding resistance with a press die is small, and to provide a chemical component having a high melting point and good adhesiveness. By forming a film having a composition on the surface of the plating layer of a zinc-based plated steel sheet, it is premised that it is excellent in press formability, and it is excellent in spot weldability, adhesion and chemical conversion treatment depending on the application as appropriate. To provide a galvanized steel sheet.

[0016]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that an appropriate Fe-Ni-O-based coating film is formed on the surface of the galvanized steel sheet. It has been found that press formability, spot weldability, adhesiveness, and chemical conversion treatment properties can be improved by forming.

That is, the conventional galvanized steel sheet is inferior to the cold-rolled steel sheet in press formability. This is because the sliding resistance between the zinc-plated steel sheet and the press die is large. The reason for this is that, under a high surface pressure, the low melting point zinc and the mold cause an adhesion phenomenon. In order to prevent this, it is effective to form a film having 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. Fe-N in the present invention
Since the i-O-based coating is hard and has a high melting point, the sliding between the plating layer surface and the press mold during press molding is performed by forming the Fe-Ni-O-based coating on the surface of the zinc-based plated steel sheet. The resistance decreases, the zinc-plated steel sheet easily slides into the press die, and the press formability improves.

[0018] The conventional galvanized steel sheet is inferior to the cold rolled steel sheet in continuous hitting property in spot welding. The cause is that the molten zinc at the time of welding comes into contact with the copper of the electrode to melt and form a brittle alloy layer, so that the deterioration of the electrode becomes severe. Therefore, as a method for improving the continuous hitting property of a zinc-based plated steel sheet, it is effective to form a high melting point film on the plated surface.
The present inventors have studied various coatings to improve the spot weldability of galvanized steel sheets.
It has been found that oxide films are particularly effective. Although the details of this reason are not clear, Ni reacts with Zn to form a Zn-Ni alloy with a high melting point, and the Ni oxide has a very high melting point and has a semiconducting property, so that it has an electric conductivity. It is considered that the degree is high among various coatings.

It has been known that the adhesiveness of the conventional galvanized steel sheet is inferior to that of the cold-rolled steel sheet, but the cause has not been clarified. The present inventors have investigated the cause and found 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 surface of the steel sheet is mainly composed of Fe oxide, whereas in the case of a zinc-based plated steel sheet, the oxide film is mainly composed of Zn oxide. The adhesiveness differs depending on the composition of the oxide film.
Adhesion was inferior to oxide. Therefore, by forming a film containing Fe oxide on the surface of a galvanized steel sheet as in the present invention, it is possible to improve the adhesiveness.

The chemical conversion property of the conventional galvanized steel sheet is as follows:
The inferiority to the cold rolled steel sheet is that the phosphate film crystals formed are coarse and non-uniform due to the high Zn concentration on the steel sheet surface, and the quality of the phosphate crystals is different. to cause. When the Zn concentration on the surface of the steel sheet is high, the phosphate crystals are mainly composed of whipite, and the secondary adhesion of hot water after coating is poor. This is because, since the Fe concentration in the phosphate film is low, the chemical conversion film is condensed when exposed to a humid environment after coating, and loses adhesion to the steel sheet.

In order to suppress the condensed water of the chemical conversion treatment film,
It is effective to include metals such as Fe and Ni in the phosphate crystals. By forming the Fe—Ni—O-based coating of the present invention, Ni and Fe in the coating are incorporated into the phosphate crystals during the chemical conversion treatment, resulting in a chemical conversion coating having good adhesion. It was found that dense and uniform phosphate crystals were formed, and not only the secondary adhesion to hot water but also the corrosion resistance were improved.

As described above, at least Ni and Fe metals and Ni
And a mixed film containing Fe oxide (hereinafter referred to as “Fe—N
It has been found that by appropriately forming the “i-O-based film”), a zinc-based plated steel sheet having excellent press formability, spot weldability, adhesiveness, and chemical conversion treatment properties can be obtained. That is, the above-described Fe—Ni—O
It is an essential requirement of the present invention that the system film is formed on the surface of the plating layer.

The present invention has been made based on the above-mentioned findings, and the zinc-plated steel sheet of the present invention has an Fe—Ni—O-based film formed on at least one surface of a plated layer. A galvanized steel sheet, wherein the Fe-
The adhesion amount of the Ni-O-based coating is 10 to 1500 mg / m in terms of the total amount of metal elements in the Fe-Ni-O-based coating.
² , and the oxygen content of the Fe—Ni—O-based coating is 0.5 to 30 wt. % (Hereinafter referred to as “first invention”).

The galvanized steel sheet according to the present invention is a galvanized steel sheet having a Fe—Ni—O film formed on at least one surface of a plating layer, wherein the Fe—Ni—
The adhesion amount of the O-based film is in the range of 10 to 1500 mg / m ^{2 in} terms of the total amount of metal elements in the Fe—Ni—O-based film, and Fe
The ratio of the Fe content (wt.%) To the sum of the content (wt.%) And the Ni content (wt.%) Is more than 0 to
0.9, and the Fe-Ni-O-based coating has an oxygen content of 0.5 to 30 wt. % (Hereinafter referred to as "second invention").

The galvanized steel sheet according to the present invention is a galvanized steel sheet having a Fe—Ni—O-based film formed on at least one surface of a plating layer, wherein the Fe—Ni—O—
The adhesion amount of the O-based film is in the range of 10 to 1500 mg / m ^{2 in} terms of the total amount of metal elements in the Fe—Ni—O-based film, and Fe
The ratio of the Fe content (wt.%) To the sum of the content (wt.%) And the Ni content (wt.%) Is 0.05.
~ Less than 1.0, and the Fe-Ni-
The oxygen content of the O-based coating is 0.5 to 30 wt. % (Hereinafter referred to as “third invention”).

The galvanized steel sheet having excellent press formability, spot weldability, adhesion and chemical conversion treatment properties of the present invention is characterized in that at least one of the surfaces of the plating layer has Fe--Ni
-O-based coating formed zinc-plated steel sheet, wherein the amount of the Fe-Ni-O-based coating adhered to the Fe-Ni-O
10 to 1500 m, in terms of the total amount of metal elements in the system coating
g / m ² , and the Fe content (wt.%) and the Ni content (wt.%) in the Fe—Ni—O-based coating.
%) And the sum of the Fe content (wt.%) And the sum of
In the range of 0.05 to 0.9, and the Fe-N
The oxygen content of the i-O-based coating is 0.5 to 10 wt. % (Hereinafter referred to as “fourth invention”).

The zinc-plated steel sheet of the present invention, which is more excellent in press formability, spot weldability, adhesion and chemical conversion treatment properties, is the zinc-plated steel sheet of the fourth invention, wherein the Fe-Ni-O-based coating is used. Of the Fe
-In terms of the total amount of metal elements in the Ni-O-based coating,
In the range of 1200 mg / m ² ,
The Fe content (w) with respect to the sum of the Fe content (wt.%) And the Ni content (wt.%) In the O-based coating
t. %) Is in the range of 0.1 to 0.3 (hereinafter, referred to as “fifth invention”).

[0028]

Next, the reason why the amount of the Fe—Ni—O based film formed on the surface of the plated layer of the zinc-based plated steel sheet of the present invention and the composition thereof are limited as described above will be described.

[Amount of Fe-Ni-O-based Coating] As described above, press-formability, spot weldability, adhesion, and chemical conversion treatment are improved by forming the Fe-Ni-O-based coating. However, if the amount of the Fe—Ni—O-based film adhered is less than 10 mg / m ^{2 in} terms of the total amount of metal in the film, the effects of improving press formability, spot weldability, adhesiveness, and chemical conversion properties cannot be obtained. .

On the other hand, the amount of adhesion is 1 in the total amount conversion.
If it exceeds 500 mg / m ² , the above-mentioned effects are saturated, and furthermore, the formation of phosphate crystals is suppressed, and the chemical conversion property deteriorates. In order to improve the chemical conversion property, the total amount conversion value is desirably 1200 mg / m ² or less. Therefore, the amount of the Fe—Ni—O-based coating film to be deposited should be limited to the range of 10 to 1500 mg / m ² , preferably to the range of 10 to 1200 mg / m ^{2 in} terms of the total amount of metal in the film. is there.

[Oxygen content of Fe—Ni—O type coating] F
By containing an appropriate amount of oxygen in the e-Ni-O-based coating, press formability and spot weldability are improved. However, when the oxygen content of the Fe—Ni—O-based coating is 0.5 wt. %, The metallic properties of the film become so strong that the effect of improving press formability and spot weldability is not exhibited. On the other hand, when the oxygen content is 10 wt.
%, The amount of the oxide becomes too large, so that the formation of phosphate crystals is suppressed, and the chemical conversion property deteriorates.
However, the upper limit of the oxygen content is not required for applications that do not require excellent chemical conversion property. However, if the oxygen content is 30 wt. %, Fe-Ni
The -O-based film is entirely composed of an oxide, so that the metal alone does not exist in the film. So, at least,
It does not satisfy the essential requirement of the present invention that a mixed film containing a metal of Ni and Fe and an oxide of Ni and Fe, that is, an Fe—Ni—O-based film is present. Therefore, even when the chemical conversion property is not a problem, the oxygen content of the film is set to 30 wt. %.

Therefore, in order to improve press formability or press formability and spot weldability, it is necessary to use Fe
-The oxygen content of the Ni-O-based coating is 0.5 to 30 wt.
% And should be within the range of
In order to improve the spot weldability and the chemical conversion property, the oxygen content of the Fe—Ni—O-based coating is set to 0.5 to 1
0 wt. It should be in the range of%.

[Ratio of Fe content to sum of Fe content and Ni content in Fe—Ni—O-based coating] Fe—N
By containing an appropriate amount of Fe in the i-O-based film, the adhesiveness is improved. This is because the adhesiveness of a metal having a higher surface potential is better, and Fe belongs to the metal having the highest surface potential. Therefore, the more Fe is contained, the more the adhesion is improved. However, the Fe content (wt.%) And the Ni content (wt.%) In the Fe—Ni—O-based coating film
And the ratio of the Fe content (wt.%) To the sum of
"Fe / Fe + Ni in film") is 0.05w
t. %, The effect of improving the adhesiveness is not exhibited. However, the lower limit of Fe / Fe + Ni in the film is not required for applications that do not require excellent adhesiveness. However, when Fe / Fe + Ni in the coating is 0 (zero), Fe-
The oxide will not be present in the Ni-O-based film. In this case, at least a mixed film containing a metal of Ni and Fe and an oxide of Ni and Fe, that is,
It does not satisfy the essential requirement of the present invention that the Fe-Ni-O-based coating is present. Therefore, even if the adhesion is not a problem, the content of Fe / Fe + Ni in the coating should be more than 0 (zero). On the other hand, when Fe / Fe + Ni in the coating is 0.9
Is exceeded, the content of Ni present in the coating is reduced, so that the proportion of the high melting point Zn-Ni alloy formed during welding is reduced, so that the deterioration of the electrode becomes severe and the effect of improving the spot weldability is reduced. Not demonstrated. However, for applications that do not require excellent spot weldability, the upper limit of Fe / Fe + Ni in the coating is not required. However, when Fe / Fe + Ni in the coating is 1.0, Fe-N
Ni will not be present in the i-O-based film. In this case, at least metals of Ni and Fe, and
A mixed film containing oxides of Ni and Fe, that is, Fe-
It does not satisfy the essential requirement of the present invention, that is, the presence of a Ni—O-based coating. Therefore, even if the spot weldability is not a problem, the Fe / Fe + Ni in the film should be less than 1.0.

Therefore, in order to improve the adhesiveness, it is necessary to use F
Fe / Fe + Ni in the e-Ni-O-based coating is reduced to 0.05 to
It should be within the range of less than 1.0, and in order to improve the spot weldability, the Fe / Fe + Ni
Should be in the range greater than 0 (zero) to 0.9.

The Fe / Fe + Ni content in the coating is 0.1%.
When the content is in the range of 0.3 to 0.3, the adhesion is further improved. Therefore, in order to improve the adhesion, Fe / Fe +
It is desirable to set Ni in the range of 0.1 to 0.3.

The zinc-based plated steel sheet requires certain properties (four properties such as press formability, spot weldability, adhesiveness and chemical conversion properties) to be provided depending on the application. Therefore, the amount of the Fe-Ni-O-based film adhered, and , Its oxygen content and the proper range of Fe / Fe + Ni in the coating should be determined. The appropriate range is as follows from the above.

[Fe, necessary for the characteristics to satisfy a predetermined value,
-Amount of Ni-O coating, oxygen content and Fe / Fe + Ni in the coating] A zinc-coated steel sheet having a Fe-Ni-O coating formed on its surface is considered to have excellent press formability. In order to achieve this, the coating amount: 10 to 1500 mg / m ² and the oxygen content of the coating: 0.5 to 30 wt. % In order to obtain excellent press formability and spot weldability, the amount of coating: 10 to 1500 mg / m ² , the oxygen content of the film: 0.5 to 30 wt. %, Fe / Fe + Ni in the coating: more than 0 to 0.9, In order to obtain excellent press formability and adhesion, the amount of adhesion: 10 to 1500 mg / m ² , and the oxygen content of the coating: 0. 5 to 30 wt. %, Fe / Fe + Ni in the coating: 0.05 to less than 1.0, In order to obtain excellent press formability, spot weldability, adhesion and chemical conversion treatment, the amount of adhesion: 10 to 1500 mg / m ^2. Oxygen content of the film: 0.5 to 10 wt. %, Fe / Fe + Ni in the coating: 0.05 to 0.9. Further, in the above, in order to further improve the press formability and adhesiveness, the adhesion amount is 10 to 1200 mg / m ² , and the oxygen content of the film is 0.5 to 10 wt. %, Fe / Fe + Ni in the coating: 0.1 to 0.3.

The Fe—Ni—O-based coating contains Zn, Co, Mn, Mo, and A contained in the underlying plating film.
The above-described effects can be obtained even when an oxide, a hydroxide, or a metal element containing elemental elements such as l, Ti, Sn, W, Si, Pb, and Ta is included.

The zinc-based plated steel sheet used in the present invention means that a plated layer is formed on a steel sheet as a base material by one or more methods such as a hot-dip plating method, an electroplating method, and a vapor phase plating method. Steel plate. The chemical composition of the zinc-based plating layer is, in addition to pure zinc, Fe, Ni, Co, Mn,
Cr, Al, Mo, Ti, Si, W, Sn, Pb, Nb
And a metal or oxide such as Ta, or an organic substance, and may be a single layer or a multi-layer plating layer containing a predetermined amount of one or more of them. Further, the plating layer may contain fine particles such as SiO ₂ and Al ₂ O ₃ . In addition, as a zinc-based plated steel sheet, a multi-layer plated steel sheet composed of a plurality of layers having the same component elements and different compositions from each other in a plated layer, It is also possible to use a functionally graded plated steel sheet in which is continuously changed.

Further, in the present invention, Fe as an upper layer
The Ni—O-based film is not limited by its forming method, but includes displacement plating, immersion in an oxidant-containing aqueous solution, cathodic electrolytic treatment and anodic electrolytic treatment in an oxidant-containing aqueous solution. Spraying, roll coating, etc., laser CVD, optical CVD, vacuum deposition, and vapor phase plating such as sputter deposition.

Since the above-mentioned Fe—Ni—O-based coating is formed on at least one surface of the plated layer of the zinc-based plated steel sheet, in any process of the vehicle manufacturing process, Depending on whether or not the steel sheet is used, a steel sheet whose film is formed on one surface or both surfaces can be appropriately selected.

[0042]

Next, the present invention will be described in more detail with reference to examples. A zinc-based plated steel sheet within the scope of the present invention (hereinafter referred to as “the present invention specimen”) and a zinc-based plated steel sheet outside the scope of the present invention (hereinafter referred to as “the comparative specimen”) are prepared by the following methods. Was prepared.

First, a zinc-based plated steel sheet (hereinafter, referred to as an “original sheet”) before forming a Fe—Ni—O-based film was prepared. The prepared original plate was composed of the following seven plating types, and symbols were given according to the plating method, plating composition, and plating adhesion amount.

GA: galvannealed steel sheet (10w
t. % Fe, the balance being Zn), and the adhesion amount is 60 on both sides.
g / m ² . GI: Hot-dip galvanized steel sheet, adhesion amount is 9 on both sides
0 g / m ² . EG: Electrogalvanized steel sheet, the amount of adhesion is 40 on both sides
g / m ² . Zn-Fe: Electric Zn-Fe alloy plated steel plate (15w
t. % Fe), and the adhesion amount is 40 g / m ² on both sides. Zn-Ni: Electric Zn-Ni alloy plated steel plate (12w
t. % Ni), and the adhesion amount is 30 g / m ² on both sides. Zn-Cr: Electric Zn-Cr alloy plated steel sheet (4 wt.
% Cr), and the adhesion amount is 20 g / m ² on both sides. Zn-Al: hot-dip Zn-Al alloy plated steel sheet (5 wt.
% Al), and the adhesion amount is 60 g / m ² on both sides.

An Fe—Ni—O-based film was formed on the surface of the plating layer of the original plate (zinc-based plated steel sheet) thus prepared by any one of the following three methods. [Formation Method A] In a mixed solution of iron sulfate and nickel sulfate containing an oxidizing agent, the original plate was subjected to a cathodic electrolytic treatment to form a predetermined Fe-Ni-O-based film on the surface of the original plate. Here, the nickel sulfate concentration was kept constant at 100 g / l, the iron sulfate concentration was changed to various predetermined values, and p
H was constant at 2.5, bath temperature was constant at 50 ° C., hydrogen peroxide was used as an oxidizing agent, and the concentration was changed to various predetermined values to adjust the oxygen content of the coating. [Formation Method B] An aqueous solution containing nickel chloride concentration of 120 g / l and various predetermined concentrations of iron chloride was sprayed on a master plate, and the oxygen content of the Fe—Ni—O-based film was measured in a mixed atmosphere of air and ozone. By drying while adjusting, a predetermined Fe-Ni-O-based film was formed on the surface of the original plate. [Formation Method C] Nickel chloride concentration of 120 g / l and various predetermined concentrations of iron chloride, pH = 2.5-3.
5. The original plate was immersed in an aqueous solution having a bath temperature of 50 ° C. By adjusting the immersion time, the amount of the Fe-Ni-O-based film deposited was changed to various predetermined values. Also, by adjusting the pH,
The oxygen content of the Fe—Ni—O-based coating was changed to various predetermined values. Also, in order to adjust the oxygen content, a predetermined oxidizing agent is appropriately added to the aqueous solution, and a predetermined Fe-Ni- An O-based film was formed.

According to the above-described forming method, a predetermined Fe-Ni
By forming an -O-based film on the surface of a predetermined original plate, a test sample of the present invention and a test sample for comparison were obtained. Preparation of the test sample of the present invention and the test sample for comparison are performed in two separate steps. In the first test ("Example 1"), the examples of the first to fifth inventions and the second test ("Embodiment 2") was mainly performed for the purpose of the embodiment of the fifth invention.

Regarding the Fe—Ni—O-based film of each specimen, the amount of the film adhered, Fe / Fe + Ni in the film, and
The oxygen content of the coating was measured as follows.

[Adhesion amount of film and Fe / Fe in film
+ Ni] For the specimens whose plating types are GI, EG, Zn—Cr, and Zn—Al, the Fe—Ni—O-based film is coated with dilute hydrochloric acid together with the surface layer of the lower plating film (Zn-based plating, the same applies hereinafter). By dissolving and exfoliating and performing quantitative analysis of Fe, Ni and metal by ICP method, Fe-Ni-
The amount and composition of the O-based film were measured. Next, Fe / Fe + Ni in the film was calculated. The plating type is GA, Z
For the test specimens of n-Fe and Zn-Ni, since the lower plating film contains the component elements in the Fe-Ni-O-based film, the ICP method uses the upper-layer Fe-Ni-O-based film as a component element. It is difficult to completely separate the component elements in the lower plating film. Therefore, only the component elements of the Fe—Ni—O-based film not contained in the lower plating film were quantitatively analyzed by the ICP method. Furthermore, 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 film from the film surface by the XPS method.
In this measurement method, the distance between the depth at which the component element of the Fe—Ni—O-based film not contained in the lower plating film is the maximum concentration and the position at half the depth where the element is no longer detected. Was the thickness of the Fe—Ni—O-based coating. Then, from the result of the ICP method and the result of the XPS method,
The amount and composition of the Fe—Ni—O-based coating were calculated.
Next, Fe / Fe + Ni in the film was calculated. [Oxygen Content of Film] The oxygen content of the film was determined from the results of depth analysis by Auger electron spectroscopy (AES).

[Example 1] Tables 1 to 3 show that the test pieces Nos. 1 to 52 and Comparative Nos. 1 to 15 of the present invention prepared in the first test were The zinc-based plating type and the method of forming the Fe-Ni-O-based film on the original plate are indicated by symbols, and the amount of the Fe-Ni-O-based film attached, the amount of Fe / Fe + Ni in the film, and the oxygen content of the film are shown. Show.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

For each of the specimens in Tables 1 to 3, the evaluation of press formability was made by the coefficient of friction between the specimen and the bead, and the evaluation of spot weldability was made by the number of continuous spots in the continuous spot test.
The adhesion was evaluated by the peel strength after the surfaces of the test pieces were adhered to each other, and the chemical conversion treatment was evaluated by the state of formation of phosphate crystals. Each evaluation test method is as follows, and the results are shown in the same table.

[Friction Coefficient Measurement Test] In order to evaluate press formability, the friction coefficient of each specimen was measured by the following apparatus. FIG. 1 is a schematic front view showing a friction coefficient measuring device. As shown in FIG. 1, a sample 1 for measuring a coefficient of friction collected from a specimen is fixed to a sample table 2, and the sample table 2 is fixed to the upper surface of a horizontally movable slide table 3. The lower surface of the slide table 3 has a row
And a slide table support 5 having an upper end and a lower end for measuring the pressing load N of the bead 6 against the friction coefficient measurement sample 1 by pushing up the slide table support 5. A dressing 7 is mounted on the slide table support 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. The load cell 8 is a slide table.
It is attached to one end of the bull 3. As a lubricating oil, Noxlast HN manufactured by Nippon Parkerizing Co., Ltd.
Was applied to the surface of Sample 1 to perform a test.

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

FIG. 2 is a schematic perspective view showing the shapes 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. In addition, this dimension
The shaped bead will be referred to as type A.

[Continuous spotting test] In order to evaluate the spot weldability, a continuous spotting test was performed for each specimen. Two specimens of the same NO. Were stacked, sandwiched between a pair of electrode tips from both sides, and resistance welding (spot welding) in which current was concentrated by applying pressure was performed continuously under the following welding conditions. . -Electrode tip: dome type with a tip diameter of 6 mm-Pressure: 250 kgf-Welding time: 0.2 seconds-Welding current: 11.0 KA-Welding speed: 1 point / sec. As the evaluation of the continuous hitting property, the diameter of the molten and solidified metal part (shape: goishi, hereinafter referred to as a nugget) generated at the joint of two superposed welding base materials (specimens) during spot welding was 4 points. The number of continuous dots welded until the thickness became less than × t ^1/2 (t: sheet thickness of one sheet) was used. The number of hit points is hereinafter referred to as electrode life.

[Adhesion Test] The following test specimens for adhesion test were prepared from each specimen. FIG. 3 is a schematic perspective view illustrating the assembling process. As shown in FIG.
A test specimen 13 in which two test specimens 10 having a length of 200 mm and a length of 200 mm were overlapped and bonded via a spacer 11 having a diameter of 0.15 mm so that the thickness of the adhesive 12 became 0.15 mm.
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 rate of / min, and the average peel strength (n = 3 times) when the test piece was peeled was measured. 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 treatment test] In order to evaluate the chemical conversion treatment, the following test was conducted. Each specimen was treated with an immersion type zinc phosphate treatment liquid (PBL3080, manufactured by Nippon Parkerizing Co., Ltd.) for a base material for automobile coating under normal conditions to form a zinc phosphate film on the surface. The crystal state of the zinc phosphate film thus formed was observed with a scanning electron microscope (SEM). It was divided into three stages according to its crystal state. The signs of the evaluation categories and their contents are as follows. ：: The crystals of the zinc phosphate film are dense and small. Δ: The crystals of the zinc phosphate film are slightly coarse and large. ×: The crystals of the zinc phosphate film are coarse.

From the test results of the test pieces of the present invention shown in Tables 1 and 2, the following matters are clear. When the amount of the Fe—Ni—O-based coating is 10 to 1500
mg / m ² and the oxygen content of the coating is 0.5 to 30 wt. % (The specimens of the present invention Nos. 1 to 52), that is, all the zinc-based plated steel sheets within the range of the first invention have a small coefficient of friction.
Therefore, it is excellent in press formability. When the amount of the Fe—Ni—O-based coating is 10 to 1500
mg / m ² and Fe / Fe +
Ni is in the range of more than 0 to 0.9, and the oxygen content of the film is 0.5 to 30 wt. % (The specimens of the present invention Nos. 1 to 46, 48, 49 and 51), that is, the galvanized steel sheets within the range of the second invention, all have a low coefficient of friction and are continuous. The number of hit points is large, and therefore, it is excellent in press formability and spot weldability. When the amount of the Fe—Ni—O-based coating is 10 to 1500
mg / m ² and Fe / Fe +
Ni is in the range of 0.05 to less than 1.0, and the oxygen content of the film is 0.5 to 30 wt. % (Inventive specimens Nos. 1 to 45, 47,
48, 50, 51 and 52), that is, all of the zinc-coated steel sheets within the scope of the third invention have a low coefficient of friction and a high peel strength after bonding, and therefore have poor press formability and adhesion. Are better. When the amount of the Fe—Ni—O-based coating is 10 to 1500
mg / m ² and Fe / Fe +
Ni is in the range of 0.05 to 0.9, and the oxygen content of the film is 0.5 to 10 wt. % (Inventive specimens Nos. 1 to 6 and 12 to 45), that is, all galvanized steel sheets within the scope of the fourth invention have a low coefficient of friction and a continuous number of dots. In many cases, the peel strength after bonding is high, and the crystals of the chemical conversion treatment film are dense and small, and therefore, are excellent in press formability, spot weldability, adhesion, and chemical conversion treatment characteristics. The adhesion amount of the Fe—Ni—O-based film is 10 to 1200
mg / m ² and Fe / Fe +
Ni is in the range of 0.1 to 0.3, and the oxygen content of the film is 0.5 to 10 wt. % (Specimens Nos. 12, 14, 16, 18, and 2 of the present invention).
5, 28, 39, 40, 43 and 45), that is, all the zinc-coated steel sheets within the scope of the fifth invention have a low coefficient of friction, a large number of continuous impact points, a high peel strength after bonding, and In addition, the crystals of the chemical conversion coating film are dense and small, and are therefore excellent in press formability, spot weldability, adhesion and chemical conversion treatment, and particularly excellent in press moldability and adhesion.

From the test results of the comparative specimens in Table 3, the following matters are clear. In the case where the Fe—Ni—O-based film was not formed (comparative test pieces Nos. 1 to 7), the plating type was G:
Even if it is represented by A, GI, EG, ZnFe, ZnNi, ZnCr or ZnAl, it is inferior in press formability, spot weldability and chemical conversion treatment. The amount of the Fe—Ni—O-based coating is too small outside the range of the present invention (comparative specimens Nos. 8, 9, 12, and 1).
5) is also inferior in press formability, spot weldability, and chemical conversion treatment, as in the case of no film formation. If the amount of the Fe-Ni-O-based coating film is excessive outside the range of the present invention (comparative specimens Nos. 10 and 13),
Poor chemical conversion property. Even if only the amount of the coating is within the range of the present invention, the sample whose oxygen content is too small outside the range of the present invention (comparative specimens Nos. 11 and 14) has the following properties. Poor weldability and adhesion.

As described above, the zinc plating type of the original plate is represented by the symbols GA, GI, EG, ZnFe, ZnNi, Z
Regardless of which of nCr and ZnAl is used, the method of forming the Fe—Ni—O-based coating further includes:
It does not change even if it is represented by any of A, B and C.

Example 2 In Example 2, a detailed test was performed by further adding the conditions of the amount of Fe—Ni—O-based coating and the composition of the composition as compared with Example 1, and the press formability was evaluated. The test was performed under more severe test conditions, and the significant difference in the coefficient of friction between the specimens was more clearly evaluated.

Tables 4 to 9 show the results obtained in the secondary tests,
Regarding each specimen No. 201 to 312 (including both the specimen of the present invention and the comparative specimen), the zinc plating type of the original plate and the method of forming the Fe-Ni-O-based film on the original plate are described below. Symbols indicate the amount of the Fe—Ni—O-based film attached, the amount of Fe / Fe + Ni in the film, and the oxygen content of the film.

[0065]

[Table 4]

[0066]

[Table 5]

[0067]

[Table 6]

[0068]

[Table 7]

[0069]

[Table 8]

[0070]

[Table 9]

For each of the specimens in Tables 4 to 9, press formability, spot weldability, adhesiveness and chemical conversion treatment were evaluated in the same manner as in Example 1 described above. It was also described in.

However, in evaluating the press formability,
In the friction coefficient measurement test, the shape of the bead was changed as follows. That is, a test using a bead in which the length of the sliding surface of the bead 6 in FIG. 2 in the sliding direction of the sample was increased from 3 mm to 60 mm was added to all the specimens.

FIG. 5 is a schematic perspective view showing the shape and dimensions of a bead whose sliding direction is lengthened. The bead having this size and shape is called type B, and the bead shown in FIG. 2 is called type A.

From the test results of the test samples of the present invention in Tables 4 to 9, the following matters are clear. In the specimen of the present invention, the first; second; third;
Within the scope of each of the fourth inventions, press moldability; press moldability and spot weldability; press moldability and adhesiveness; press moldability, spot weldability, adhesiveness, and chemical conversion treatment according to the respective inventions. Is excellent. Influence of adhesion amount on press formability and spot weldability It can be seen that if the adhesion amount of the film is within the range of the present invention, the adhesion amount of the film increases, and the press formability and spot weldability are improved. (Specimens No. 204-21
6, 251-253, 260-262, 269-27
1, 278-280, 287-289, 296-29
8, and 305 to 307). Effect of Fe / Fe + N on press formability and adhesion
Influence of i When Fe / Fe + Ni in the film is in the range of 0.1 to 0.3, the press formability is particularly excellent (specimen No. 2
Bead type with a coefficient of friction of 23 to 230: see column B). Further, when Fe / Fe + Ni in the film is 0.1 to 1.0.
In particular, the adhesiveness is stable and good within the range of less than (specimens Nos. 223 to 236 and 263 to 2).
65, 272 to 274, 281 to 283, 290 to 29
2, 299-301 and 310-312).

When the results of Example 1 and Example 2 are combined, the amount of coating and the amount of Fe / Fe + Ni in the coating are within a narrower range, that is, the amount of coating is 10 to 120%.
Within the range of 0 mg / m ² , Fe / Fe + Ni in the coating was
0.1 to 0.3, and the oxygen content of the film is 0.5 to 10 wt. %, It can be understood that a galvanized steel sheet having excellent press formability and adhesiveness can be obtained.

[0076]

The present invention has been 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 plating layer, the sliding resistance between the plating layer surface and the press mold during press forming of the zinc-based plated steel sheet is reduced. This makes it easier for the zinc-based plated steel sheet to slide into the press die. Also, the presence of a Fe—Ni—O-based coating,
In particular, a high melting point Z is used during welding to contain a predetermined amount of Ni.
Since the formation ratio of the n-Ni alloy is ensured, the wear of the electrode is suppressed, and as a result, the continuous hitting property in spot welding is improved. Further, since a predetermined amount of Fe having a high surface potential, which is effective for improving the adhesiveness, is contained, the peel strength of the adhesive plate is improved. Further, the chemical conversion coating has excellent adhesion since Ni and Fe in the Fe—Ni—O-based coating are taken into the phosphate crystals, and has a secondary structure of warm water due to the formation of dense and uniform phosphate crystals. It also has excellent adhesion.

Therefore, according to the present invention, a zinc-coated steel sheet having excellent press formability, a zinc-coated steel sheet having excellent press formability and spot weldability, and a zinc-coated steel sheet having excellent press formability and adhesiveness , And can provide any of the zinc-based plated steel sheets excellent in press formability, spot weldability, adhesiveness and chemical conversion treatment properties,
An extremely useful effect is brought about 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 a bead in FIG.

FIG. 3 is a schematic perspective view illustrating a process of assembling a test specimen for an adhesion test.

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

FIG. 5 is a schematic perspective view showing the shape and dimensions of another bead in FIG.

[Explanation of symbols]

 1 Sample for friction coefficient measurement, 2 Sample table, 3 Slide table, 4 Roller, 5 Slide table support, 6 Bead, 7 First load cell, 8 Second load cell, 9 Ray 10 specimens, 11 spacers, 12 adhesives, 13 specimens for adhesion test, P tensile load, F sliding resistance.

────────────────────────────────────────────────── ─── Continued on the front page (72) Takayuki Urakawa, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Masaaki Yamashita 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Inside (72) Inventor Tetsu Hashimoto 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (56) References JP-A-3-17282 (JP, A) JP-A-4-48082 (JP) JP-A-3-191093 (JP, A) JP-A-53-115624 (JP, A) JP-A-1-196551 (JP, A) JP-A-9-143660 (JP, A) 9-41186 (JP, A) JP-B 55-30596 (JP, B2) JP-B 4-50387 (JP, B2) JP-B 3-10714 (JP, B2) International publication 96/10103 (WO, A1) ) (58) investigated the field (Int.Cl. ^7, B name) C25D 3/00 - 7/12 C23C 2/00 - 2/40 C23C 22/00 - 22/86 C23C 28/00 - 30/00

Claims (5)

(57) [Claims] 1. The method according to claim 1, wherein at least one surface of the plating layer has
A zinc-plated steel sheet having a Fe-Ni-O-based film formed thereon, wherein the amount of the Fe-Ni-O-based film adhered is the Fe-Ni-coated film.
10 to 150 in terms of the total amount of metal elements in the -O-based coating
0 mg / m ² , and the oxygen content of the Fe—Ni—O-based coating is 0.1 mg / m ² .
5 to 30 wt. % Zinc-plated steel sheet, characterized by being within the range of less than 0.1%. 2. The method according to claim 2, wherein at least one surface of the plating layer has
A zinc-plated steel sheet having a Fe-Ni-O-based film formed thereon, wherein the amount of the Fe-Ni-O-based film adhered is the Fe-Ni-coated film.
10 to 150 in terms of the total amount of metal elements in the -O-based coating
0 mg / m ² , and the Fe content (w
t. %) And the Ni content (wt.%), The ratio of the Fe content (wt.%) Is more than 0 to 0.9, and the Fe-Ni-O-based coating Has an oxygen content of 0.5 to 3
0 wt. % Zinc-plated steel sheet, characterized by being within the range of less than 0.1%. 3. The method according to claim 1, wherein at least one surface of the plating layer has
A zinc-plated steel sheet having a Fe-Ni-O-based film formed thereon, wherein the amount of the Fe-Ni-O-based film adhered is the Fe-Ni-coated film.
10 to 150 in terms of the total amount of metal elements in the -O-based coating
0 mg / m ² , and the Fe content (w
t. %) And the content of Ni (wt.%) With respect to the sum of the Fe content (wt.%) Is in the range of 0.05 to less than 1.0, and the Fe—Ni—O The oxygen content of the system coating is 0.5 to 3
0 wt. % Zinc-plated steel sheet, characterized by being within the range of less than 0.1%. 4. The method according to claim 1, wherein at least one surface of the plating layer has
A zinc-plated steel sheet having a Fe-Ni-O-based film formed thereon, wherein the amount of the Fe-Ni-O-based film adhered is the Fe-Ni-coated film.
10 to 150 in terms of the total amount of metal elements in the -O-based coating
0 mg / m ² , and the Fe content (w
t. %) And the Ni content (wt.%)
The ratio of the content (wt.%) Is in the range of 0.05 to 0.9, and the oxygen content of the Fe—Ni—O-based coating is 0.5 to 1.
0 wt. % Zinc-plated steel sheet having excellent press formability, spot weldability, adhesiveness and chemical conversion treatment properties. 5. The adhesion amount of the Fe—Ni—O-based coating is as follows:
In terms of the total amount of metal elements in the Fe—Ni—O-based coating, the content is in the range of 10 to 1200 mg / m ² ,
The ratio of the Fe content (wt.%) to the sum of the Fe content (wt.%) and the Ni content (wt.%) in the e-Ni-O-based coating is 0.1 to 0. 5. The press formability, spot weldability,
Galvanized steel sheet with excellent adhesive and chemical conversion properties.