JPH11197704A - Plating steel sheet excellent in color tone, adhesion, and weldability and method for producing the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a method for stably producing a steel sheet for plating excellent in color tone, adhesion and weldability at low cost. SOLUTION: The surface roughness is Ra 0.1 to 0.4, the interval of uneven peaks lower than 0.1 to 5 μm, the number of uneven peaks is 200 or more per inch, and the straight line connecting the peaks of uneven peaks is the surface roughness. In the method of plating steel sheet where the number of irregularities with an average line of 40 ° or less is 60% or more of the whole irregularities, and the method of performing cathodic electrolytic treatment in electrolyte after degreasing and pickling the steel sheet, the steel sheet surface during pickling For example, a method in which a steel plate is used as an anode in an acidic aqueous solution having a bath temperature of 10 to 60 ° C. and a pH of 0 to 4 at a current density of 1 to 100 A / dm ² and 1 to 50 Clon / dm.
⁽²⁾ a method in which electrolytic pickling is carried out in an acidic aqueous solution having a bath temperature of 10 to 60 ° C and a pH of 0 to 4 containing 1 to 20 g / l of Fe ³⁺ ion
A method of immersing a steel plate for 10 seconds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating steel sheet having a beautiful printed appearance, high adhesion and excellent weldability, and a method for producing the same. The steel sheet produced by the method of the present invention has excellent printed appearance, adhesion and weldability after plating, and is particularly suitable as a material for beverage cans.

[0002]

2. Description of the Related Art Plated steel sheets, which are widely used as materials for various containers such as beverage cans, food cans, etc., have recently increased the willingness of consumers to purchase as well as to protect their contents after canning. To achieve this, beautiful printing is applied to the outer surface of the can. In such printing, the color tone of the surface of the plated steel sheet, which is the printing base, has a large effect on the color tone after printing, and one of the main factors that govern the color tone of the plated steel sheet is the unevenness of the surface. It is known.

[0003] As a method for producing a surface unevenness in which the color tone of a plated steel sheet is excellent, a method in which a steel sheet is rolled with a temper rolling roll having a predetermined surface roughness, and the unevenness of the roll is transferred to the surface of the steel sheet (Japanese Patent Application Laid-Open No. H05-1993). No. 305303) has been proposed. However, in the above-mentioned method, there is a problem that as the number of rolled coils increases, the roll surface is abraded, the unevenness of the roll surface changes, and the color tone of the plated steel sheet decreases.
In order to suppress the abrasion of the roll surface, a method of applying a hard chromium plating to the roll surface has been proposed, but it is impossible to sufficiently suppress the change in the uneven shape. Therefore,
In order to produce a plating steel sheet having a constant surface color tone, it is necessary to frequently change the rolling roll, which causes a problem that productivity is reduced and production cost is increased.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides a plating steel sheet having not only a printed appearance but also excellent adhesion and weldability, and a stable and inexpensive production of the steel sheet. It provides a method.

[0005]

According to the present invention, there is provided a method for manufacturing a semiconductor device having a surface roughness Ra.
Is 0.1 to 0.4 μm, the interval between uneven peaks lower than the surface roughness is 0.1 to 5 μm, and the number of uneven peaks is 1.
A color tone characterized by not less than 200 per inch, and not more than 60% of the total unevenness, wherein the angle between the straight line connecting the peaks of the unevenness peak and the average line of the surface roughness is 40 ° or less; The present invention relates to a plating steel sheet having excellent adhesion, weldability, and a method for producing the same. As a method of manufacturing the above-mentioned steel sheet for plating, a method of manufacturing a coated steel sheet in which a steel sheet is subjected to cathodic electrolytic treatment in an electrolytic solution after subjecting the steel sheet to degreasing pickling, in which fine irregularities are generated on the steel sheet surface during pickling. This is effective in terms of manufacturing cost and stable manufacturing. As a method for generating fine irregularities on the steel sheet surface during pickling, (1)
Bath temperature is 10-60 ° C, pH is 0-4 in acidic aqueous solution,
Using a steel plate as the anode and a current density of 1 to 100 A / dm ² ,
50 click - method for performing electrolytic pickling Ron / dm ^{2, (2)}
Bath temperature is 10-6 containing 1-20 g / l Fe ³⁺ ions
It is effective to immerse the steel sheet in an acidic aqueous solution at 0 ° C. and a pH of 0 to 0.1 for 0.1 to 10 seconds.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The present inventors conducted detailed studies on the effects of the uneven texture of the plating steel sheet on the adhesion and weldability, using plated steel sheets using plating steel sheets having various uneven textures. As a result, as an uneven texture having excellent adhesion and weldability, the surface roughness Ra is 0.1 to 0.4 μm, and the interval between uneven peaks lower than the surface roughness is 0.1 to 5 μm.
m, and the number of peaks and depressions is 200 or more per inch, and the number of projections and depressions whose angle between a straight line connecting the vertices of the peaks and projections and the average line of surface roughness is 40 ° or less is 60% of the entire projections and depressions. The above texture was newly found.
In the present invention, the reason why the texture of the steel sheet surface is limited will be described below.

[0007] Surface roughness R of commonly used steel plate for cans
a has a standard and its surface roughness is in the range of 0.1 to 0.4 μm. Therefore, the surface roughness is 0.1 to 0.4 μm
It is necessary to

The reason why the peaks of the unevenness must be 200 or more per inch and the interval between the peaks is 0.1 to 5 μm is to obtain a plating steel sheet having excellent adhesion and weldability. As to the adhesion between the resin film and the plated steel sheet, the texture of the unevenness of the plated surface has a great influence. This is due to the fact that as the number of irregularities increases, the surface area increases, the contact area between the resin and the plating film increases, and the anchoring effect increases. In this case, when the interval between the peaks and depressions is larger than 5 μm, a sufficient anchoring effect cannot be obtained, and the interval between the peaks and depressions is 0.1 μm.
If it is smaller, the resin does not sufficiently penetrate between the uneven peaks, and the adhesion between the resin and the plating film does not occur. Therefore, the peak interval at which excellent adhesion is obtained is 0.1 to 5 μm.
Also, the unevenness texture of the plating surface has a great effect on the weldability of the plated steel sheet. For example, if the number of irregularities is too small, the number of contact points between the steel plates will decrease. At that time, local heating occurs at the time of welding and dust is generated, so that a lower limit value is generated for the number of irregularities. Therefore, 200 or more irregular peaks are required per inch.

The reason why the angle between the straight line connecting the peaks of the peaks and depressions and the average line of the surface roughness is limited to 40 ° or less is to obtain a plated steel sheet having an excellent color tone after resin coating. Since coated steel sheets for containers are generally used after painting and printing, the appearance after painting and printing is important.
A particularly bright appearance is preferred. The appearance after painting and printing is determined by how attenuated light that enters the resin film from the atmosphere is reflected by the plating surface and comes out of the resin film again. Among the light attenuation, the absorption by the resin film or the plating film is determined by the physical properties of the resin or the plating metal, and the unevenness of the plating steel sheet has almost no influence. The unevenness of the plating steel sheet affects the appearance because the light reflected on the surface of the plating steel sheet is totally reflected at the interface between the resin film and the atmosphere, and the light does not come out into the atmosphere, leading to darkening of the appearance. That is. After light incident on the resin film from the air is reflected on the plating surface, the straight line connecting the peaks of the peaks and depressions is the average line of the surface roughness in order to eliminate total reflection at the resin film and the air interface. It is necessary that the angle formed is 40 ° or less. From various studies, the present inventors have found that if the number of irregularities at which the straight line connecting the peaks of the irregularities peaks and the average line of the surface roughness is 40 ° or less is 60% or more of the entire irregularities, sufficient color tone is obtained. Was obtained. However, in view of the aforementioned adhesion and weldability, it is desirable that the angle formed by the straight line connecting the peaks of the peaks and depressions with the average line of the surface roughness is 5 ° or more.

Next, as a means for obtaining the uneven texture of the steel sheet for plating as described above, the surface of the temper rolling roll is processed into a predetermined uneven texture and transferred to the steel sheet for plating by temper rolling. However, this method cannot stably provide an optimum uneven texture due to abrasion of the roll surface. Therefore, the present inventors focused on the pickling process performed for the purpose of removing iron oxide in an industrial plating process, performing electrolytic pickling using a plating steel sheet as an anode, and including Fe ³⁺ ions. The inventors invented a method for stably forming an uneven texture by immersing a steel plate in an acid pickling solution to dissolve the steel plate in an anode.

The effects of various pickling conditions on the texture of the unevenness formed on the steel sheet for plating were examined in detail, and the following conditions were newly found as the pickling conditions for obtaining the optimum texture of the unevenness. Bath temperature is 10-60 ° C, pH is 0
1 to 100 A / dm using a steel plate as an anode in an acidic aqueous solution of No. 4
^A method of carrying out electrolytic pickling at 1 to 50 coulombs / dm ² at a current density of ² and acidity at a bath temperature of 10 to 60 ° C. and a pH of 0 to 4 containing 1 to 20 g / l of Fe ³⁺ ions This is a method of immersing a steel sheet in an aqueous solution for 0.1 to 10 seconds.

In the above, an acidic solution having a pH of 0 to 4 is used.
What is used is that the steel sheet melts and Fe²⁺Hydrated oxide
This is to prevent adhesion to the steel sheet surface. Furthermore,
Fe ²⁺Produced by air oxidation of iron³⁺Produces hydrated oxides
In order to avoid this, the pH is desirably 2 or less. acid
Sulfuric acid, sulfate, hydrochloric acid, phosphoric acid, phosphate,
PH 0 to 1
4 can be used. In particular, sulfuric acid and sulfate
It is most recommended because of its excellent economy and chemical dissolution ability.
If the bath temperature is too low, the anode dissolution rate of the steel
The time required to obtain a constant texture
If it is too high, local melting will occur and the texture
The temperature is preferably from 10 to 60 ° C., since no cooling is obtained.

In the above, the conditions for anodic electrolysis of the steel sheet need to be changed according to the uneven texture of the original steel sheet for plating. When the current density is too low, the energization time for obtaining the predetermined uneven texture is prolonged and the productivity is reduced. However, when the current density is too high, local melting occurs and the predetermined uneven texture cannot be obtained. /
dm ² is preferred. On the other hand, when the amount of electricity is too small, the amount of dissolution of the steel sheet decreases and a predetermined uneven texture cannot be obtained. However, when the amount of electricity is too large, the amount of dissolution of the steel sheet increases and the color tone is reduced, so that 1 to 50 coulombs / dm ² is required. preferable.

The reason for using an acidic solution containing 1 to 20 g / l of Fe ³⁺ ions is to etch the steel sheet with Fe ³⁺ ions to form surface irregularities. Fe ³⁺
When the ion is too low, because the longer it takes to obtain a predetermined uneven texture, dissolution rate too fast too large steel, it is difficult to stably produce a predetermined uneven texture, Fe ³⁺ The ion is preferably 1 to 20 g / l. In addition, the immersion time in the pickling solution needs to be changed depending on the original texture of the steel sheet for plating, but if it is too short, the predetermined uneven texture cannot be obtained, and if it is too long, the amount of dissolution of the steel sheet increases. The time is preferably 0.1 to 10 seconds to reduce the color tone.

Examples of the present invention and comparative examples will be described below.
Table 1 shows the results of evaluating the seam weldability, the adhesion by the T-peel peel test, and the color tone of the tin-plated steel sheet.
Shown in In each of the examples, weldability and adhesion (4 kg /
5 mm or more) and color tone (120 or more), and is suitable as a tin-plated steel sheet for welding cans.

[0016]

[Table 1]

After a thin steel plate having a thickness of 0.22 mm is electrolytically degreased in a 5% NaOH solution, pickling conditions are changed to obtain a steel plate for plating having various uneven textures on the surface of the steel plate, and 1 g in a generally used ferrostan bath. / after tin plating m ^2, subjected to cathodic electrolysis was chromating in a solution consisting of chromic anhydride and sulfuric acid, metal chromium 10 mg / m ² on the upper layer of the tin plating layer, further 10 mg / m ² on the upper layer thereof Of chromium oxide hydrate (in terms of metallic chromium) was produced to obtain a tin-plated steel sheet for a welding can.

Table 2 shows the results of evaluating the retort resistance and the color tone of the tin-free steel sheet by a T-peel peel test. In all of the examples, the adhesion (2 kg /
5 mm or more) and color tone (110 or more), which are suitable as TFS for resin coating.

[0019]

[Table 2]

After a 0.18 mm steel sheet is electrolytically degreased in a 5% NaOH solution, the pickling conditions are changed to obtain a steel sheet for plating having various uneven textures on the steel sheet surface, and chromium plating is performed in a generally used chrome plating bath. After that, chromate treatment is carried out in a generally used electrolytic chromic acid bath, and 100 mg / m ^{2 of} chromium metal is further added thereto.
A tin-free steel sheet comprising a hydrated chromium oxide layer of mg / m ² (calculated as chromium metal) was produced.

The details of the evaluation method will be described below. 1) Evaluation of seam weldability Seam weldability was evaluated using a seam welder using a copper wire as an intermediate electrode. The test material is 210 ° C x 20 in advance.
For a minute. The welding conditions were: lap allowance 0.6 mm,
Pressure 40kgf, welding speed 50mpm, current frequency 4
At 00 Hz, the evaluation criteria were determined based on the width of the appropriate current range. The lower limit of the appropriate welding current range was determined by the welding strength, and the upper limit was determined by the occurrence of dust (thus the molten iron projected in a splash shape). The appropriate current range is practically sufficient if it is 200 A or more, but 400 A is considered from the viewpoint of stable manufacturability of welding.
The above is desirable.

2) Evaluation of adhesiveness An epoxyphenol-based paint was applied to the surface of the plated steel sheet by 25 m.
After applying g / m ^{2, the} coating was baked at 180 ° C. for 10 minutes, then the same paint was applied in the same amount on the opposite surface and baked at 210 ° C. for 10 minutes. This sample was cut into a width of 5 mm and a length of 120 mm, and the surface opposite to the preceding painted surface was overlapped.
With a nylon adhesive and hot press
After preheating at 00 ° C. for 45 seconds, pressure bonding was performed at 200 ° C. for 30 seconds under a pressure of 3 kg / cm ² to prepare a test piece. The tin-plated steel sheet was coated with a 200 mm / min. A T-peel test was performed at a constant tensile speed of, and the peel strength was measured.
There is no practical problem if the peel strength is 2 kg / 5 mm or more, but when applied to a beverage can using a paint having a high coating film hardness, 3 kg / 5 mm or more is desirable. The tin-free steel sheet was prepared by immersing the test piece in a 0.6% NaCl aqueous solution at 90 ° C. for 7 days and then using a tensile tester at 200 mm / min.
A T-peel test was performed at a constant tensile speed of, and the peel strength was measured. Peeling strength is practically sufficient if it is 2 kg / 5 mm or more in general use. However, when applied to beverage cans containing a large amount of chloride ions that deteriorate the adhesion as contents, 3
kg / 5 mm or more is desirable.

3) Evaluation of color tone To evaluate the color tone after coating and printing, a 10 μm transparent polyester resin was applied to a plated steel sheet. Using a Shimadzu spectrophotometer UV-2100S, C light source, viewing angle 1
Under the condition of 0 °, the colorimetry of diffuse reflection light and specular reflection light is performed, and L
Using the L value of the ab color system as an index of lightness, the color tone was evaluated by the sum of the L values of diffuse reflection and specular reflection.

4) Evaluation of uneven texture The Ra of the surface of the steel sheet for plating, the number of peaks per inch, and the inclination angle of the uneven peak are averaged on a roughness curve using a laser type three-dimensional roughness meter. The angle was determined. Regarding the inclination angle of the uneven peak, the ratio of peaks having an inclination angle of 40 ° or less was further calculated. (See Fig. 1)

[0025]

According to the present invention, it becomes possible to stably produce a steel sheet for plating excellent in color tone, adhesion and weldability at low cost.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing the surface roughness of the present invention.

Claims (4)

[Claims] 1. The surface roughness Ra is 0.1 to 0.4 μm, and the interval between uneven peaks lower than the surface roughness is 0.1 to 5 μm.
m, the number of peaks and depressions is 200 or more per inch, and the number of projections and depressions where the angle between the straight line connecting the peaks of the peaks and depressions and the average line of the surface roughness is 40 ° or less is less than the total number of projections and depressions. A plating steel sheet excellent in color tone, adhesion, and weldability, characterized by being 60% or more. 2. A method for producing a plated steel sheet having excellent color tone, adhesion and weldability by subjecting a steel sheet to degreased pickling and then subjecting the steel sheet to cathodic electrolytic treatment in an electrolytic solution. A method for producing a plating steel sheet having excellent color tone, adhesion, and weldability, characterized by causing unevenness. 3. An acidic aqueous solution having a bath temperature of 10 to 60 ° C. and a pH of 0 to 4, with a steel plate serving as an anode and 1 to 100 A / dm ^2.
The color tone, the adhesion, and the electrolytic pickling according to claim ² , wherein electrolytic pickling is performed at a current density of 1 to 50 coulombs / dm2.
Manufacturing method of steel sheet for plating with excellent weldability. 4. The composition of claim 1, comprising 1 to 20 g / l of Fe ³⁺ ions.
4. The color tone, adhesion, and weldability according to claim 2 and 3, wherein the steel sheet is immersed in an acidic aqueous solution having a bath temperature of 10 to 60C and a pH of 0 to 4 for 0.1 to 10 seconds. Method of manufacturing steel sheet for plating.