KR102393728B1 - Zinc-based electroplated steel sheet - Google Patents

Abstract

This zinc-based electroplating steel sheet includes a steel sheet and a zinc-based electroplating layer positioned on at least one surface of the steel sheet and having a hairline extending in a predetermined direction on the surface. In the zinc-based electroplating layer, the three-dimensional average surface roughness Sa (50 μm) is continuously measured along a predetermined direction, and R50 which is the ratio of the Sa (50 μm) in the adjacent region formed by two adjacent regions. , and when an adjacent region having an R50 of less than 0.667 or greater than or equal to 1.500 is referred to as an adjacent region A, the proportion of the number of adjacent regions A is 30% or more.

Description

Zinc-based electroplated steel sheet

The present invention relates to a zinc-based electroplated steel sheet.

this application claims priority based on the patent application No. 2018-071944 for which it applied to Japan on April 3, 2018, The content is used here.

BACKGROUND ART Articles that attract people's attention, including electrical equipment, building materials, and automobiles, generally require designability. As a method of improving the designability, a method of coating the surface of an article or attaching a film is common, but in recent years, the application of materials utilizing the texture of metal is increasing, mainly in Europe and the United States that are oriented to nature. From the viewpoint of utilizing the texture of the metal, since painting or resin coating impairs the texture of the metal, stainless steel or aluminum material having excellent corrosion resistance is used as a material of the article even without painting. In addition, in order to improve the designability of stainless steel or aluminum materials, arc-shaped fine irregularities called vibration are given or embossed processing is performed, but the appearance with fine linear irregularities called hairline is particularly preferred is being used

Hairline finish (HL finish) is one of the surface finishes of stainless steel materials, and in JIS G4305:2012, it is defined as "an abrasive of an appropriate particle size and polished to produce continuous abrasive streaks".

However, since stainless steel and aluminum materials are expensive, inexpensive materials to replace these stainless steel materials and aluminum materials are desired. As one of such alternative materials, it has the same high designability and moderate corrosion resistance as that of stainless steel or aluminum material, and has a hairline appearance suitable for use in electric equipment or building materials, etc. Hereinafter, there are steels with excellent “metallic feel”).

As a technique for imparting appropriate corrosion resistance to steel, a technique for applying zinc plating or zinc alloy plating having excellent sacrificial corrosion resistance to steel is widely used. It is a technology related to a steel material in which a hairline design is given to such zinc plating or zinc alloy plating (hereinafter, zinc plating and zinc alloy plating may be collectively referred to as "zinc plating"). A technique of forming a light-transmitting adhesive layer and a light-transmitting film layer plating layer with respect to the surface of a plating layer having a surface roughness Ra (arithmetic mean roughness) of 0.1 to 1.0 µm in a right angle direction (see Patent Document 1 below), The roughness parameters (Ra and PPI) in the hairline direction and in the direction orthogonal to the hairline formed on the surface layer of the Zn-Al-Mg-based hot-dip plated layer are within a specific range, and a transparent resin coating layer is formed on the surface of the Zn-Al-Mg-based hot-dip plated layer. (See Patent Document 2 below), or a technology of coating a resin having a surface roughness within a certain range on a steel sheet to which a texture is transferred by rolling to Zn and Zn-based alloy plating (Patent Document 3 below) see) has been proposed.

Japanese Registered Utility Model Publication No. 3192959 Japanese Patent Laid-Open No. 2006-124824 Japanese Patent Publication No. 2013-536901 International Publication No. 2015/125887

However, in the technique of coating an organic resin on a steel sheet to which a hairline design has been provided, proposed in Patent Documents 1 to 3, the hairline design can be realized and certain corrosion resistance can be expressed, but the resin There was a problem that the metallic feeling was lost due to the coating.

Here, as a method of forming a hairline, a steel sheet rolling method in which a plated steel sheet for forming a hairline is rolled by a rolling roll having a predetermined roughness, and plating grinding for grinding the surface of a plated steel sheet to form a hairline There is a law. The loss of the metallic feeling as described above was particularly remarkable in the plated steel sheet in which the hairline was formed by the steel sheet rolling method. Although the reason for the significant loss of metallic feeling is not clear, in the plated steel sheet in which the hairline is produced by the steel sheet rolling method, the incident light is diffusely reflected on the entire surface of the plating layer by the crystal grains of the plating existing on the outermost surface of the plating layer. It is thought to be because Therefore, when it is assumed that the resin coating demonstrated below is performed with respect to the surface of the plated steel sheet on which the hairline was formed, formation of the hairline by the steel plate rolling method is also considered inappropriate.

As a method for improving glossiness, a method of refining plating crystal grains by adding a predetermined organic material additive to an electroplating solution is known (for example, refer to Patent Document 4). However, when the crystal grains of the plating were made finer, there was a problem that the working adhesion with the resin film was lowered when the upper layer of the plating was coated with a resin. Moreover, in the method described in the said patent document 4, in order to obtain smooth plating, it was necessary to use an organic substance additive, and there existed a problem that the drag-out (waste liquid) treatment cost of a plating liquid increased.

Moreover, since the stainless steel material itself has good corrosion resistance by the oxide film which exists on the surface, coating for corrosion resistance improvement is unnecessary. That is, since the metal matrix itself can be used on the surface, the problem of loss of metallic feeling by resin coating does not exist in the first place. On the other hand, when resin coating is applied to stainless steel materials, it is an object to impart coloration or other texture. Therefore, in stainless steel materials, the loss of the metallic feeling which the present inventors discovered did not become a problem. This situation is the same also for an aluminum material.

Also, depending on the application, as a calm texture, a matte or external appearance having a metallic feel and suppressed gloss may be preferred. As described above, the hairline is usually formed by grinding or grinding the surface with an abrasive/grinding belt, or the like, or rolling using a rolling roll. is inevitably high gloss, and it was difficult to realize a matte or appearance with low gloss.

In addition, in the zinc-based plated steel sheet, resin coating is often applied to maintain corrosion resistance and aesthetics, but the adhesion between the zinc-based plated layer and the resin film may decrease with the formation of a hairline.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to have a hairline appearance, suppress a rise in gloss, and maintain a metallic feeling when a resin film is formed on the plating upper layer, while maintaining high film adhesion To provide a zinc-based electroplated steel sheet capable of realizing

The present inventors earnestly study the method for improving the metallic feeling, and if the diffuse reflection in the outermost surface of the plating layer can be suppressed, even when the surface of the plating layer is coated with resin, it is thought that it is possible to improve the metallic feeling. The present inventors have conducted further studies with this idea, and as a result, in order to suppress diffuse reflection, by providing a smooth portion having a surface roughness in the microscopic range below a predetermined threshold on the plating layer surface, they have come to the knowledge that diffuse reflection can be suppressed.

In addition, the present inventors have found that by appropriately adjusting the ratio of the rough part and the smooth part whose surface roughness in the microscopic range exceeds a predetermined threshold on the surface of the plating layer, an excessive increase in gloss can be suppressed while achieving both metallic feeling and film adhesion. could get In addition, the "surface roughness in the microscopic range" will be described later.

The present inventors earnestly examine the distribution state of rough parts and smooth parts under the various knowledge as described above, and even when an organic resin coating layer is provided on the upper layer of the zinc-based electroplating layer, excessive increase in gloss is achieved while achieving both metallic feeling and film adhesion. The present invention was completed by considering the conditions for suppression.

The gist of the present invention completed based on these findings is as follows.

(1) A zinc-based electroplated steel sheet according to an aspect of the present invention includes a steel sheet and a zinc-based electroplating layer positioned on at least one surface of the steel sheet and having a hairline extending in a predetermined direction on the surface.

In the zinc-based electroplating layer, a three-dimensional average surface roughness of a region of 50 μm×50 μm in each of a hairline direction in which the hairline is stretched and a hairline orthogonal direction perpendicular to the hairline direction Sa (50 μm) is successively measured to calculate R 50 , which is the ratio of Sa (50 μm) in the adjacent region formed by the two neighboring regions, and the adjacent region where R 50 is less than 0.667 or 1.500 or more When referring to the adjacent region A, the proportion of the number of the adjacent regions A is 30% or more in either the hairline direction and the hairline orthogonal direction.

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(2) The zinc-based electroplated steel sheet according to (1) may further include an organic resin coating layer having light-transmitting properties and having a thickness of 10 µm or less as an upper layer of the zinc-based electroplating layer.

(3) In the zinc-based electroplated steel sheet described in (2), the organic resin coating layer contains a colorant, and the color tone of the organic resin coating layer according to the L ^* a ^* b ^* color system using a CIE standard light source D65 is used. A value of (a ^*2 +b ^*2 ) ^0.5 indicating saturation may be 10 or less when measured by the specular light removal method using .

(4) In the zinc-based electroplated steel sheet according to (2) or (3), in the state in which the organic resin coating layer is present, the surface roughness Ra (CC) measured along the direction orthogonal to the hairline, and the organic resin The surface roughness Ra (MC) of the zinc-based electroplating layer measured along the hairline orthogonal direction after peeling the coating layer may satisfy the relationship shown by the following formula (1).

Ra(CC)<Ra(MC)<5×Ra(CC) . . . Equation (1)

(5) In the zinc-based electroplated steel sheet according to any one of (1) to (4), the zinc-based electroplating layer may have a base iron exposure rate of less than 5%.

(6) In the zinc-based electroplated steel sheet according to any one of (1) to (5), the amount of the zinc-based electroplating layer attached may be 10 g/m 2 to 60 g/m 2 .

(7) In the zinc-based electroplated steel sheet according to any one of (1) to (6), both the zinc-based electroplating layer or the organic resin coating layer provided as an upper layer of the zinc-based electroplating layer and the zinc-based electroplating layer The surface roughness Ra of the steel sheet after removal of may be 1.0 µm or more and 1.7 µm or less.

(8) In the zinc-based electroplated steel sheet according to any one of (1) to (7), the zinc-based electroplated layer contains at least one element selected from the group consisting of Fe, Ni, and Co in a total of 5 mass % - 20 mass % may be contained.

(9) In the zinc-based electroplating steel sheet according to any one of (1) to (8), both the zinc-based electroplating layer or the organic resin coating layer provided as an upper layer of the zinc-based electroplating layer and the zinc-based electroplating layer The surface roughness Ra of the steel sheet after removing may be 60% or less of the thickness of the zinc-based electroplating layer.

As described above, according to the present invention, it is possible to achieve a film adhesion when a resin film is formed on the plating upper layer while suppressing excessive increase in gloss while having a hairline appearance and excellent metallic feeling.

1A is an explanatory view schematically showing an example of the structure of a zinc-based electroplated steel sheet according to an embodiment of the present invention.
1B is an explanatory view schematically showing an example of the structure of a zinc-based electroplated steel sheet according to the embodiment.
2A is an example of an image when the surface of the zinc-type electroplating layer which the zinc-type electroplated steel sheet which concerns on the same embodiment has is observed with SEM (scanning electron microscope).
2B is an example of an image at the time of observing the surface of the zinc-type electroplating layer which the zinc-type electroplating steel plate which concerns on the same embodiment has with a normal camera.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of this invention is described in detail, referring an accompanying drawing. In addition, in the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, so that redundant descriptions are omitted.

(About the overall composition of zinc-based electroplated steel sheet)

First, the overall configuration of the zinc-based electroplated steel sheet according to the embodiment of the present invention will be described in detail with reference to FIGS. 1A and 1B . 1A and 1B are explanatory views schematically showing an example of the structure of the zinc-based electroplated steel sheet according to the present embodiment.

The zinc-based electroplated steel sheet according to the present embodiment has at least a steel sheet as a base material and a zinc-based electroplating layer positioned on either surface of the steel sheet, and the surface of the zinc-based electroplating layer is subjected to hairline processing.

In general hairline processing, a smooth portion corresponding to the hairline (that is, a portion smoothed by crushing by hairline processing) is provided so as to be physically continuous along a predetermined direction, and the continuation of such smooth portion is recognized as a hairline. . However, in the hairline processing performed on the surface of the zinc-based electroplating layer according to the present embodiment, even though the smooth portions are not physically continuous, when a person observes the surface of the zinc-based electroplating layer according to the present embodiment, a predetermined It has the characteristic of recognizing as if the hairline is connected in the direction of Hereinafter, the zinc-based electroplated steel sheet according to the present embodiment having such characteristics will be described in detail.

As schematically shown in Fig. 1A, the zinc-based electroplated steel sheet 1 according to the present embodiment includes a steel sheet 11 as a base material and a zinc-based electroplating layer located on either surface of the steel sheet 11 ( 13) at least. Further, as shown in Fig. 1B, the zinc-based electroplated steel sheet 1 according to the present embodiment preferably further includes a light-transmitting organic resin coating layer 15 on the surface side of the zinc-based electroplating layer 13. Do.

<About the description>

The steel sheet 11, which is the base material of the zinc-based electroplated steel sheet 1 according to the present embodiment, is not particularly limited, and various types known in accordance with mechanical properties (eg, tensile strength, etc.) required for the zinc-based electroplated steel sheet are not limited thereto. It is possible to use a steel plate appropriately.

[About the surface shape of the substrate]

In the zinc-based electroplated steel sheet 1 according to the present embodiment, the zinc-based electroplating layer 13 or the organic resin coating layer 15 and the zinc-based electroplating layer located on the upper layer side of the zinc-based electroplating layer 13 ( 13) It is preferable that the surface roughness Ra of the steel plate 11 after removing both are 1.0 micrometer or more and 1.7 micrometers or less. Here, Ra is the arithmetic mean roughness prescribed|regulated to JIS B 0601:2013. When surface roughness Ra is less than 1.0 micrometer, since it may become difficult to provide the zinc-based electroplating layer 13 which has the surface shape demonstrated in detail below, it is unpreferable. When the surface roughness Ra exceeds 1.7 µm, even if the zinc-based electroplating layer 13 having a surface shape to be described in detail below is provided, there is a possibility that it may be difficult to recognize that the hairline is stretched in a predetermined direction. It is not advisable because

In the steel sheet 11 according to the present embodiment, both the zinc-based electroplating layer 13 or the organic resin coating layer 15 and the zinc-based electroplating layer 13 located on the upper side of the zinc-based electroplating layer 13 . It is more preferable that the surface roughness Ra of the steel sheet 11 after removal of is 1.1 µm or more and 1.5 µm or less.

In addition, in the present invention, the surface roughness Ra is not significantly different from the direction in which the hairline is recognized as being stretched and the direction orthogonal to the hairline, but the range of the surface roughness Ra is in the direction orthogonal to the hairline measure

In addition, the surface roughness Ra of the steel sheet 11 is both the zinc-based electroplating layer 13 or the organic resin coating layer 15 and the zinc-based electroplating layer 13 located on the upper layer side of the zinc-based electroplating layer 13 . After removal, it is preferable that it is 60% or less of the thickness of the zinc-type electroplating layer 13. When the surface roughness Ra is more than 60% of the thickness of the zinc-based electroplating layer 13, it is preferable because there is a possibility of impairing corrosion resistance when the zinc-based electroplating layer 13 having a surface shape described in detail below is provided. don't

In the steel sheet 11 according to the present embodiment, both the zinc-based electroplating layer 13 or the organic resin coating layer 15 and the zinc-based electroplating layer 13 located on the upper side of the zinc-based electroplating layer 13 . It is more preferable that the surface roughness Ra of the steel plate 11 after removal of is 40% or less of the thickness of the zinc-based electroplating layer 13.

In addition, the thickness of the zinc-based electroplating layer 13 is calculated|required as follows. First, the plated steel sheet is immersed in an acid solution containing an inhibitor to dissolve the zinc-based electroplating layer 13 . Next, the thickness of the zinc-based electroplating layer 13 is converted from the deposition amount of the zinc-based electroplating layer 13 obtained in this way and the specific gravity of the metal contained in the zinc-based electroplating layer 13 .

Further, the surface roughness Ra of the steel sheet 11 after removing both the zinc-based electroplating layer 13, or the organic resin coating layer 15 formed as an upper layer of the zinc-based electroplating layer 13 and the zinc-based electroplating layer 13, When it falls within the said range, the surface roughness Ra of the steel plate 11 before forming the zinc-based electroplating layer 13 and the organic resin coating layer 15 also falls within the said range.

The surface roughness Ra as described above can be measured with a stylus type roughness meter. Here, when the surface roughness of the steel sheet 11 is measured after the zinc-based electroplating layer 13 or the organic resin coating layer 15, which will be described later, is measured, the zinc-based electroplating layer with a release agent such as a solvent or remover that does not corrode the steel sheet. What is necessary is just to measure surface roughness Ra after removing (13) and the organic resin coating layer 15.

<About zinc-based electroplating layer>

In addition, a zinc-based electroplating layer is formed on one surface of the steel sheet 11 as described above. As schematically shown in FIG. 1A , the zinc-based electroplating layer 13 according to the present embodiment is a smooth portion visually recognized as a hairline extended in a predetermined direction (direction indicated by an arrow in the lower portion of FIG. 1A ). It has (103) and coarse parts 101a, 101b visually recognized as a part which is not a hairline. Here, in the following description, "the direction in which the hairline is visually recognized" is abbreviated as "the hairline direction", and "the direction perpendicular to the direction recognized as the stretching direction of the hairline" is "orthogonal to the hairline" direction” is abbreviated.

In FIG. 1A, the rough part 101a is a recessed part, and is the part which avoided the influence of the grinding|polishing accompanying a hairline process. In addition, the rough part 101b is a part that remains after hairline processing in spite of the fact that the surface of the zinc-based electroplating layer 13 is in a position away from the surface of the steel sheet 11 in the depth direction, and is usually a rough part 101b. The portion of is also continuous over a certain range in the hairline direction. In the rough part 101b of FIG. 1A, also in the surface part of the zinc-type electroplating layer 13, it has shown typically that a rough part may exist. In addition, the rough part and the smooth part will be described in detail again below.

[Type and composition of zinc-based electroplating layer]

As the zinc-based electroplating layer 13 according to the present embodiment, electrozinc plating or electrozinc alloy plating (hereinafter, collectively referred to as "zinc-based electroplating") is used.

First, with respect to plated metal, plating other than zinc-based plating has poor sacrificial corrosion resistance, so it is not suitable for use in which a cut cross-section is unavoidably exposed in use. In addition, when the zinc concentration in the zinc-based electroplating layer 13 is too low, the sacrificial corrosion-corrosive ability is lost. Therefore, it is preferable that the zinc alloy plating contains 65% by mass or more of zinc with respect to the total mass of the zinc-based electroplating layer 13 . .

As a plating method, a hot-dip plating method, a thermal spraying method, a vapor deposition plating method, etc. exist other than electroplating. However, the hot-dip plating method is unsuitable because the appearance quality is deteriorated by solidification patterns such as spangles or dross unavoidably mixed in the plating layer. In addition, in the thermal spraying method, the uniformity of the appearance cannot be ensured due to the voids inside the plating film, so it is not suitable. In addition, the vapor deposition method is unsuitable because the film formation rate is slow and productivity is insufficient.

Accordingly, in the zinc-based electroplated steel sheet 1 according to the present embodiment, electroplating is used to apply zinc-based plating to the surface of the steel sheet.

Here, when the zinc-based electroplating layer 13 according to the present embodiment is formed by using electrozinc alloy plating, such electrozinc alloy plating is Co, Cr, Cu, Fe, Ni, P, Sn, Mn, Mo , V, W, and at least one element selected from the group consisting of Zr, and preferably contains Zn. In particular, it is preferable that the electric zinc alloy plating contains 5 mass % or more and 20 mass % or less of one or more elements selected from the element group which consists of Fe, Ni and Co in total. When the electro zinc alloy plating contains one or more elements selected from the group consisting of Fe, Ni, and Co within the range of the total content, it becomes possible to realize further excellent corrosion resistance.

Electrozinc plating and electrozinc alloy plating may contain impurities. Here, the impurity is not added consciously as a zinc-based electroplating component, but is mixed in the raw material or mixed in the manufacturing process, Al, Mg, Si, Ti, B, S, N, C, Nb, Pb , Cd, Ca, Pb, Y, La, Ce, Sr, Sb, O, F, Cl, Zr, Ag, W, H, and the like. In addition, when performing electrogalvanizing, Co, Cr, Cu, Fe, Ni, P, Sn, Mn, Mo, V, W, and Zr are mixed as impurities, although it differs depending on the type of electroplated steel sheet manufactured in the same manufacturing facility. there may be cases In the present embodiment, even if the impurities are present in a total of about 1 mass % with respect to the total mass of the plating, the effect obtained by the plating is not impaired.

In addition, in the zinc-based electroplating layer 13 in the present invention, when the Zn content is excessively reduced, the sacrificial corrosion-corrosion ability is lowered. With respect to mass, it is preferably 65% or more, more preferably 70% or more, particularly preferably 80% or more, as described above.

The composition of the zinc-based electroplating layer 13 can be analyzed, for example, in the following manner. That is, after removing the organic resin film layer with a release agent such as a solvent or remover that does not corrode the plating (e.g., Neo River S-701: manufactured by Sansai Chemical Co., Ltd.), the zinc-based electroplating layer is dissolved with hydrochloric acid containing an inhibitor, etc. Then, the composition of the zinc-based electroplating layer 13 may be analyzed by an ICP (Inductively Coupled Plasma) emission spectroscopy apparatus.

[About the adhesion amount of the zinc-based electroplating layer 13]

It is preferable that the adhesion amount of the zinc-type electroplating layer which concerns on this embodiment is 10 g/m<2> or more. If the desired corrosion resistance can be guaranteed, the deposition amount of the zinc-based electroplating layer is not limited, but if the deposition amount of the zinc-based electroplating layer is less than 10 g/m 2 , it is preferable because the possibility that the iron exposure rate exceeds 5% when the hairline is applied increases. don't

The adhesion amount of the zinc-based electroplating layer is more preferably 15 g/m 2 or more, still more preferably 20 g/m 2 or more. In addition, the upper limit of the adhesion amount of a zinc-based electroplating layer is not specifically prescribed|regulated, What is necessary is just to determine suitably in consideration of the manufacturing cost etc. of the plated steel plate which concerns on this embodiment, For example, it can be set as about 60 g/m<2>.

[About Jicheol Exposure Rate]

The zinc-based electroplated steel sheet 1 according to the present embodiment is premised on applying a hairline process to the surface of the zinc-based electroplating layer 13 by grinding or the like. Therefore, a part of the zinc-based electroplating layer 13 is removed in a process step such as polishing, and depending on the polishing/grinding thickness, there may be a case where the base iron (that is, the steel sheet 11) is partially exposed.

It is preferable that the base iron exposure rate of the zinc-type electroplating layer 13 which concerns on this embodiment is less than 5 %. In this embodiment, although corrosion resistance is sufficiently ensured by zinc or zinc alloy plating, when the base iron is exposed at the time of application of the hairline, long-term corrosion resistance may decrease due to the influence of galvanic corrosion, which is undesirable. . In this embodiment, since it is excellent also in long-term corrosion resistance in addition to the moderate corrosion resistance normally requested|required of a steel plate when the base iron exposure rate of the zinc-type electroplating layer 13 is less than 5 %, it has extremely favorable corrosion resistance.

The iron exposure rate of the zinc-based electroplating layer 13 is more preferably 3% or less, and still more preferably 0%.

In addition, as for the base iron exposure rate, after removing the organic resin coating layer 15 with a release agent such as a solvent or remover that does not corrode the plating, EPMA analysis is performed on 5 random squares with a side of 1 mm, and Zn for the analysis area is The area ratio which is not detected can be calculated|required by image analysis.

Since the specific hairline process is given to the surface of the zinc-type electroplating layer 13 which concerns on this embodiment, the surface becomes the characteristic surface shape accompanying a hairline process. Such a surface shape will be described in detail again below.

<About the organic resin coating layer>

The surface of the zinc-based electroplating layer 13 to which the hairline as described above is provided is preferably coated with a transparent resin (in other words, a light-transmitting resin) as schematically shown in FIG. 1B . That is, it is preferable that the organic resin coating layer 15 is provided in the surface side of the zinc-type electroplating layer 13 which concerns on this embodiment. Here, in the present embodiment, "the resin has light transmitting properties" means that the surface of the zinc-based electroplated steel sheet 1 is irradiated with light and the zinc-based electroplated steel sheet 1 is observed at an angle of 10° from the vertical direction. This means that the hairline provided to the zinc-based electroplating layer 13 can be visually recognized.

[About the components of the organic resin coating layer]

Resin used for formation of the organic resin coating layer 15 will not be specifically limited, if sufficient transparency is maintained. Examples of the resin used for forming the organic resin coating layer 15 include a polyester-based resin, an epoxy-based resin, a urethane-based resin, a polyester-based resin, a phenol-based resin, a polyethersulfone-based resin, a melamine alkyd-based resin, and an acrylic-based resin. and resins, polyamide-based resins, polyimide-based resins, silicone-based resins, polyvinyl acetate-based resins, polyolefin-based resins, polystyrene-based resins, vinyl chloride-based resins, and vinyl acetate-based resins.

In addition, as a means for improving the adhesion between the organic resin coating layer 15 and the zinc-based electroplating layer 13, a plated steel sheet comprising the steel sheet 11 and the zinc-based electroplating layer 13 within a range that does not impair the appearance. It may be subjected to an inorganic treatment, an organic-inorganic complex treatment, a surface modification treatment, or the like. Here, "damaging the appearance" means reducing the metallic feeling, such as reducing transparency, generating gloss unevenness, or generating an abnormal feeling of unevenness. As such a process, a Zr oxide process, a Zn oxide process, a silane coupling agent process, a weak acid immersion process, a weak alkali immersion process, etc. are mentioned, for example.

In order to add desired performance to the organic resin coating layer 15, you may contain various additives in the range which does not impair light transmission and an external appearance, and the range which does not deviate from the range prescribed|regulated by this invention. As performance added to the organic resin coating layer 15, corrosion resistance, sliding property, scratch resistance, electroconductivity, color tone, etc. are mentioned, for example. For example, if it is corrosion resistance, it may contain a rust preventive agent, inhibitor, etc., if it is sliding or scratch resistance, wax or beads may be contained, if it is conductive, it may contain a conductive agent, etc. You may contain a coloring agent.

Moreover, when making the organic resin coating layer 15 concerning this embodiment contain well-known coloring agents, such as a pigment and dye, it is preferable to contain a coloring agent to the extent that a hairline can be visually recognized and a metallic feeling is not lost. Here, the degree to which the hairline can be visually recognized and the metallic feeling is not lost is the color tone (L ^* a ^* ) of the organic resin coating layer 15 in a 10-degree field of view by a commercially available colorimeter using a CIE standard light source D65. b ^* refers to a range in which the relationship of chroma (a ^*2 +b ^*2 ) ^0.5 ≤ 10 when measured by the Specula Component Excluded (SCE) method.

[About the thickness of the organic resin coating layer]

It is preferable that the thickness of the organic resin coating layer 15 which concerns on this embodiment is 10 micrometers or less. When the thickness of the organic resin coating layer 15 exceeds 10 μm, the distance through which the light passes through the organic resin coating layer 15 increases, thereby reducing reflected light and decreasing the glossiness in the hairline direction. As a result, the hairline is visually recognized. It is not preferable because the possibility that it becomes difficult to do it increases. Moreover, since the shift|offset|difference of the texture of the zinc-based electroplating layer 13 surface and the shape of the surface of the organic resin coating layer 15 becomes easy to generate|occur|produce, it is unpreferable by the deformation|transformation of resin accompanying a process.

For the above reasons, the thickness of the organic resin coating layer 15 is preferably 10 µm or less, and more preferably 8 µm or less.

On the other hand, from the viewpoint of corrosion resistance, the thickness of the thinnest portion (that is, the minimum value of the thickness of the organic resin coating layer 15) as viewed from the cross section of the organic resin coating layer 15 is 0.1 μm or more, and the organic resin coating layer 15 It is preferable that an average thickness is 1.0 micrometer or more. Here, "the thinnest part" means the minimum value of the film thickness measured by cutting a length of 5 mm at an arbitrary position in a direction orthogonal to the hairline to prepare a cross-sectional sample, and measuring 20 points at 100 µm intervals, and "average "Thickness" means the average of 20 points.

The thickness of the thinnest portion of the organic resin coating layer 15 is more preferably 0.5 mu m or more, and the average thickness of the organic resin coating layer 15 is more preferably 3.0 mu m or more.

As mentioned above, the whole structure of the zinc-based electroplated steel sheet 1 which concerns on this embodiment was demonstrated in detail. 1A and 1B, although the case in which the zinc-based electroplating layer 13 and the organic resin coating layer 15 are formed on one surface of the steel sheet 11 is illustrated, two opposing pieces of the steel sheet 11 are A zinc-based electroplating layer 13 and an organic resin coating layer 15 may be formed on the surface.

(Regarding the surface shape of the zinc-based electroplating layer 13)

Next, the surface shape of the zinc-type electroplating layer 13 which concerns on this embodiment is demonstrated in detail, referring FIG. 1A.

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Hereinafter, even in the case where the organic resin coating layer 15 is present on the zinc-based electroplating layer 13, in order to achieve both a suitable metallic feeling and a suitable processing part adhesion and suppression of excessive increase in gloss, the zinc-based electroplating layer 13 is applied. Various required conditions will be described in detail.

[Distribution of grandfather and smooth part]

In the zinc-based electroplating layer 13 according to the present embodiment, when the smooth portions 103 are continuously present over a long distance in the hairline direction, the luster becomes too high, which is not preferable. On the other hand, since the continuity of a hairline is impaired when the coarse parts 101a, 101b continue excessively, it is unpreferable. Therefore, it is important that the rough part 101a, 101b is dividing the smooth part 103 which forms a hairline at the appropriate ratio.

When the three-dimensional average surface roughness Sa (50 µm) of the area of 50 µm × 50 µm is measured using a laser microscope having a display resolution of 10 nm or more in the height direction and a display resolution of 10 nm or more in the width direction, 3 If a region with a high dimensional average surface roughness Sa (50 μm) or a region with a low three-dimensional average surface roughness Sa (50 μm) is continuous, it is determined that the smooth portion 103 or the rough portions 101a and 101b are continuous. can

Here, "a region having a high three-dimensional average surface roughness Sa (50 µm) or a region having a low three-dimensional average surface roughness Sa (50 µm) is continuous” means three-dimensionally along the hairline direction or the direction orthogonal to the hairline. When the average surface roughness Sa (50 µm) is continuously measured, R50, which is the ratio of the three-dimensional average surface roughness Sa (50 µm) in two neighboring regions (hereinafter, may be referred to as adjacent regions), is calculated. When R50 value is in the range of 0.667 or more and less than 1.500.

In the zinc-based electroplating layer 13 according to the present embodiment, three-dimensional average surface roughness Sa (50 µm) is measured at n locations in the hairline direction, and three-dimensional average surface roughness Sa in an adjacent region in the hairline direction. When the value of the ratio R50 of (50 µm) is calculated at (n-1) locations, the adjacent region (the value of the ratio R50) in which 0.667 or more and less than 1.500 are out of the range (in other words, the value of the ratio R50 is less than 0.667 or 1.500 or more) The number ratio of the adjacent regions less than 0.667 or 1.500 or more is sometimes referred to as adjacent region A) is 30% or more (that is, (number of adjacent regions A)/(n-1) is 0.3 or more). In other words, the proportion of the number of adjacent regions having R50 of 0.667 or more and less than 1.500 (hereinafter referred to as adjacent region B in some cases) is less than 70%.

When the number ratio of the adjacent regions A in the hairline direction is less than 30% (that is, the number ratio of the adjacent regions B is 70% or more), the smooth portion 103 is excessively continuous and the gloss is excessively high, and the organic resin coating layer 15 ) is provided, or the roughness of the rough parts 101a and 101b is excessively continuous, so that it cannot be recognized as a continuous hairline, and the glossiness in the hairline direction is excessively reduced, thereby impairing the metallic feeling. It is not advisable because

On the other hand, there is no upper limit of the number ratio of the adjacent area|region A in the hairline direction, and 100% of the said number ratio may be sufficient.

By setting the number ratio of the adjacent regions A in the hairline direction to 30% or more, luster can be appropriately suppressed without impairing the metallic feeling, and excellent film adhesion can be realized. The said number ratio becomes like this. Preferably it is 35 % or more, More preferably, it is 40 % or more.

Also in the hairline orthogonal direction, similarly to the hairline direction, the number ratio of the adjacent area|region A shall be 30 % or more. Even when the ratio of the number of adjacent regions A in the direction orthogonal to the hairline is less than 30%, the smooth portion 103 is excessively continuous and the gloss is excessively high, and the adhesion to the processed portion when the organic resin coating layer 15 is provided decreases, or It is undesirable because the rough portions 101a and 101b are too continuous and cannot be recognized as a hairline.

In addition, there is no upper limit also about the number ratio of the adjacent area|region A in the direction orthogonal to a hairline, The said number ratio may be 100 %.

By making the said number ratio into 30 % or more, glossiness can be suppressed suitably without impairing a metallic feeling, and the outstanding film adhesiveness can be implement|achieved.

The said number ratio becomes like this. Preferably it is 35 % or more, More preferably, it is 40 % or more.

In addition, in the present invention, the ratio of the number of adjacent regions A in the hairline direction and the hairline orthogonal direction is 30% or more, for example, as shown in FIG. As a method for blocking the continuity of the hairline, as will be described later, the grinding/grinding thickness with respect to the roughness of the steel sheet is limited to a predetermined ratio. In addition, as described above, it is preferable to set the surface roughness Ra of the steel sheet 11 as the base material to a specific range.

[About the surface roughness of rough parts 101a and 101b]

As described above, in the zinc-based electroplating layer 13 according to the present embodiment, when the organic resin coating layer 15 is provided on the upper layer of the zinc-based electroplating layer 13 by setting the number ratio of the adjacent regions A to 30% or more guarantees film adhesion.

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[About the surface roughness in the smooth part]

In addition, as mentioned above, in the zinc-based electroplating layer 13 according to the present embodiment, the smooth portions 103 are present in an appropriate proportion, so that the zinc-based electroplated steel sheet 1 according to the present embodiment is suitable for metallic materials. have a sense Here, in order to realize the effect of improving the metallic feeling by the smoothing portion 103, it is preferable that the smoothing portion 103 has an appropriate surface roughness and a region of an appropriate width.

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[Surface roughness of zinc-based electroplating layer before and after formation of organic resin coating layer]

In addition, in the zinc-based electroplating layer 13 according to the present embodiment, in the state in which the organic resin coating layer 15 is present, the surface roughness Ra (CC) [unit: μm] measured along the hairline orthogonal direction; The surface roughness Ra (MC) [unit: µm] of the zinc-based electroplating layer 13 measured along the hairline orthogonal direction after peeling the organic resin coating layer 15 is expressed by the following formula (101) It is desirable to satisfy the relationship.

Ra(CC)<Ra(MC)<5×Ra(CC) . . . formula (101)

Here, each Ra in the said Formula (101) is an average value of Ra of 6 places excluding two places on the maximum side and two places on the minimum side by measuring 10 arbitrary places.

When the surface roughness Ra(MC) and Ra(CC) satisfy the relationship expressed by the formula (101), it becomes possible to more reliably realize a metallic feeling while having a hairline appearance.

The surface roughness Ra(MC) and Ra(CC) more preferably satisfy the relation shown by the following formula (103).

1.5×Ra(CC)<Ra(MC)<3.0×Ra(CC) … Equation (103)

In addition, all of the surface roughness Ra in each direction as demonstrated above can be measured with the stylus type roughness meter. Here, when the surface roughness of the zinc-based electroplating layer 13 is measured after forming the organic resin coating layer 15 to be described later, the organic resin coating layer 15 is removed with a release agent such as a solvent or remover that does not corrode the plating. Then you just have to measure it.

As mentioned above, the surface shape of the zinc-based electroplating layer 13 which concerns on this embodiment was demonstrated in detail, referring FIG. 1A.

(About the manufacturing method of zinc-based electroplated steel sheet)

Then, the manufacturing method of the zinc-type electroplating steel plate which concerns on this embodiment as demonstrated above is demonstrated briefly.

Hereinafter, first, a method of manufacturing a zinc-based electroplated steel sheet having a structure as shown in FIGS. 1A and 1B will be briefly described.

First, a steel sheet whose surface roughness has been adjusted to fall within a predetermined range is degreasing with an alkali solution and acid washed with an acid using hydrochloric acid, sulfuric acid, or the like to form a zinc-based electroplating layer. Here, it is possible to use a known method for adjusting the surface roughness of the steel sheet, for example, a method such as a method of transferring by rolling with a roll adjusted so that the surface roughness is in a desired range can be used.

As a method of forming the zinc-based electroplating layer 13, a known electroplating method can be used.

As the electroplating bath, for example, a sulfuric acid bath, a chloride bath, a zincate bath, a cyanide bath, a pyrophosphoric acid bath, a boric acid bath, a citric acid bath, other complex baths, and combinations thereof, etc. can be used.

By adding one or more monoions or complex ions selected from Co, Cr, Cu, Fe, Ni, P, Sn, Mn, Mo, V, W, and Zr in addition to Zn ions to the electric zinc alloy plating bath, Co, Cr , Cu, Fe, Ni, P, Sn, Mn, Mo, V, W, Zr can be formed in the electro-zinc alloy plating layer containing a desired amount. It is more preferable to add an additive to the plating bath in order to stabilize the ions in the plating bath or to control the plating characteristics.

The composition, temperature, flow rate, and current density and conduction pattern of the electroplating bath may be appropriately selected so as to achieve a desired plating composition, and are not particularly limited. In addition, the thickness of a zinc plating layer and an electric zinc alloy plating layer can be controlled by adjusting a current value and time within the range of the current density at which a zinc plating layer or an electric zinc alloy plating layer becomes a desired composition.

A hairline according to the present embodiment is formed on the obtained steel sheet 11 provided with the zinc-based electroplating layer 13 . As for the method of providing a hairline, the method of grinding|polishing with an abrasive belt, the method of grinding|polishing with an abrasive-grain brush, the method of grinding|polishing with a grinding|polishing/grinding machine, etc. are mentioned.

The depth and frequency of the hairline can be controlled to a desired state by adjusting the particle size of the abrasive belt or the abrasive brush, the pressing force, and the relative speed and frequency.

Here, in the polishing treatment as described above, the concave portion in which the plated crystal grains are present is maintained as it is or the concave portion is properly ground, so that the smooth portion ( The jaws 101a and 101b may be present to divide the 103 .

In the zinc-based electroplating layer 13 according to the present embodiment, the surface roughness Ra of the steel sheet 11 is applied to the surface by setting the polishing/grinding thickness (ie, polishing/grinding rate) at the time of hairline formation to 10 to 80%. You can form the desired hairline. Here, the polishing/grinding rate is a quantity expressed by how much the zinc-based electroplating layer 13 has been polished and ground with respect to the surface roughness of the steel sheet by the length in the depth direction from the surface of the zinc-based electroplating layer 13 as a starting point. The grinding/grinding thickness can be changed by adjusting the particle size of the abrasive paper, the pressing force, and the number of grinding.

By forming the hairline at a polishing/grinding rate of 10 to 80%, since the hairline is formed in a state in which the unevenness on the surface of the steel sheet 11, which is the base material, remains, even though the smooth part is not physically continuous And, it is possible to form a hairline that looks continuous in a predetermined direction.

When a grinding|polishing/grinding rate is less than 10 %, since the possibility that the number ratio of the adjacent area|region A in a hairline direction and/or a hairline orthogonal direction will become less than 30 % is high, it is unpreferable. The polishing/grinding ratio is 10% or more, preferably 20% or more, and more preferably 30% or more.

When the polishing/grinding rate is more than 80%, it is not preferable because the number ratio of the adjacent regions A in the hairline direction and/or the hairline orthogonal direction is likely to be less than 30%. The polishing/grinding ratio is set to 80% or less, preferably 70% or less, and more preferably 60% or less.

As described above, the surface roughness Ra of the steel sheet 11 can be measured with an accelerated roughness meter. In addition, with respect to two adjacent places, a grinding|polishing/grinding rate does not provide a hairline to one and a hairline to the other, but computes it from the difference of the plating adhesion amount of both. In addition, in the case of the zinc-based electroplating layer according to the present embodiment, when converting from the adhesion amount to the length, the specific gravity of 7.1 is used.

An organic resin is coat|covered on the surface of the zinc-type electroplating layer 13 which provided the hairline as needed. Here, the paint used to form the organic resin coating layer 15 follows the surface shape of the zinc-based electroplating layer 13 at the moment it is applied to the zinc-based electroplating layer 13, and once the zinc-based electroplating layer 13 is It is preferable that the leveling after reflecting the surface shape of is slow. That is, it is preferable that the coating material has a low viscosity at a high shear rate and a high viscosity at a low shear rate. Specifically, it is preferable to have a viscosity of 10 [Pa·s] or more at a shear rate of 0.1 [1/sec], and a shear viscosity of 0.01 [Pa·s] or less at a shear rate of 1000 [1/sec].

In order to adjust the shear viscosity within the above range, for example, if it is a paint using an aqueous emulsion resin, it can be adjusted by adding a hydrogen bonding viscosity modifier. Such hydrogen bonding viscosity modifiers can increase the viscosity of the paint because they bind to each other by hydrogen bonds at a low shear rate, but at a high shear rate, the viscosity decreases because the hydrogen bonds are cleaved. Thereby, it becomes possible to adjust to the shear viscosity according to the requested|required coating conditions.

The method of coat|covering an organic resin is not specifically limited, A well-known method can be used. For example, it can be formed by naturally drying or baking drying after applying the paint adjusted to the viscosity as described above by a spraying method, a roll coater method, a curtain coater method, a die coater method, or a immersion pulling method. In addition, the drying temperature and drying time, and the baking temperature and baking time may just be suitably determined so that the organic resin coating layer 15 to be formed may have the desired performance. At this time, when the temperature increase rate is slow, the time from the softening point of the resin component to the completion of baking becomes long and leveling advances. Therefore, the faster temperature increase rate is preferable.

(About the specific example of a zinc-based electroplating layer)

Next, the specific example of the zinc-based electroplating layer 13 which concerns on this embodiment formed by the method as demonstrated above is demonstrated briefly, referring FIGS. 2A and 2B. 2A is an example of an image at the time of observing the surface of the zinc-type electroplating layer which the zinc-type electroplating steel plate which concerns on this embodiment has with SEM. In addition, FIG. 2B is an image photographed with a normal camera so that the surface of the zinc-based electroplating layer 13 shown in FIG. 2A may be seen similarly to the case of visual observation.

When the zinc-based electroplating layer 13 is formed by the manufacturing method described above, for example, the zinc-based electroplating layer 13 having a surface shape as shown in FIG. 2A can be formed. In the photomicrograph shown in FIG. 2A , the height direction of the photo corresponds to the hairline direction and the width direction of the photo corresponds to the hairline direction orthogonal to the photomicrograph. As is clear from the photomicrograph of Fig. 2A, in the zinc-based electroplating layer 13 according to the present embodiment, it cannot be said that the smooth portions 103 are continuously distributed along the hairline direction, but the coarse portions ( 101), it can be seen that they exist dispersedly.

However, when macroscopically observing the zinc-based electroplated steel sheet 1 having the zinc-based electroplating layer 13 as shown in FIG. 2A , there are countless hairlines along the hairline direction as shown in FIG. 2B . perceived as doing This phenomenon originates in being distributed so that the coarse part 101 may become a predetermined ratio as mentioned above.

Example

Hereinafter, the effects of the present invention will be described in detail with reference to the invention examples. In addition, the content of the present invention is not limited by the content described in the Examples shown below.

As the base material, annealed and temper rolled steel sheet having a thickness of 0.6 mm (as a component composition, C: 0.05%, Si: 0.001%, Mn: 0.15%, P: 0.01%, S: 0.01%, sol. Al: each containing 0.04% and the balance was an Al-killed steel sheet containing Fe and impurities) was used. The above-described steel sheet was electrolytically degreased and washed with water using a Na ₄ SiO ₄ treatment solution having a concentration of 30 g/L under conditions of a treatment solution of 60° C., a current density of 20 A/dm 2 and a treatment time of 10 seconds. Next, the electrolytically degreased steel sheet was immersed in an aqueous solution of H ₂ SO ₄ having a concentration of 50 g/L at 60° C. for 10 seconds, followed by further washing with water to perform plating pretreatment. In addition, the surface roughness Ra (arithmetic mean roughness) of the steel plate was as shown in the table, respectively. In addition, a commercially available SUS304 steel sheet (B4 bright finished steel sheet) having a hairline with #180 abrasive grains was used as a comparative material (indicated as “No. SUS”). No. In SUS, a zinc-based electroplating layer was not formed, and a hairline was not provided. Also, No. In SUS, the organic resin coating layer was not formed either.

Next, with respect to the said steel plate, the plating shown in a table|surface was performed, and the zinc-type electroplating layer was formed.

As the zinc-based electroplating layer, a Zn plating film, a Zn-Ni plating film, a Zn-Fe plating film, a Zn-Co plating film, a Zn-Ni-Fe plating film, and a Zn-Co-Mo plating film were used. The formation conditions of each plating film are as follows.

<Zn plating film (No. 1 to 15, 62, 66)>

For the Zn plating film, using a plating bath of pH 2.0 containing 1.0 M of Zn sulfate heptahydrate and 50 g/L of anhydrous sodium sulfate, at a bath temperature of 50° C. and a current density of 50 A/dm2, the plating time so that the adhesion amount becomes the value shown in the table. was adjusted and formed.

<Zn-Ni plating film (No. 16 to 29, 63, 67)>

When plating was performed at a bath temperature of 50° C. and a current density of 50 A/dm 2 , the mixing ratio of Zn sulfate heptahydrate and Ni sulfate hexahydrate was adjusted so as to have the composition described in the column of “Plating species” in the table. Using a plating bath of pH 2.0 containing Zn sulfate heptahydrate and Ni sulfate hexahydrate (total 1.2M), and 50 g/L anhydrous sodium sulfate adjusted to the above mixing ratio, plating so that the adhesion amount becomes the value shown in the table. Formed by adjusting the time.

<Zn-Fe plating film (No. 30 to 43, 64, 68)>

When plating was performed at a bath temperature of 50° C. and a current density of 50 A/dm 2 , the mixing ratio of Zn sulfate heptahydrate and Fe(II) sulfate heptahydrate was adjusted so as to have the composition described in the column of “Plating species” in the table. Using a plating bath of pH 2.0 containing Zn sulfate heptahydrate and Fe(II) sulfate heptahydrate (total 1.2M) and 50 g/L anhydrous sodium sulfate adjusted to the above mixing ratio, the amount of adhesion is shown in the table. It was formed by adjusting the plating time to become .

<Zn-Co plating film (No. 44 to 57, 65, 69)>

When plating was performed at a bath temperature of 50° C. and a current density of 50 A/dm 2 , the mixing ratio of Zn sulfate heptahydrate and Co sulfate heptahydrate was adjusted so as to have the composition described in the column of “Plating species” in the table. Using a plating bath of pH 2.0 containing Zn sulfate heptahydrate and Co sulfate heptahydrate (total 1.2M), and anhydrous sodium sulfate 50 g/L, adjusted in the above mixing ratio, plating so that the adhesion amount becomes the value shown in the table. Formed by adjusting the time.

<Zn-Ni-Fe plating film (No. 58 to 59)>

When plating at a bath temperature of 50 ° C. and a current density of 50 A/dm 2 . Using a plating bath of pH 2.0 containing Zn sulfate heptahydrate, Ni sulfate hexahydrate, Fe(II) sulfate heptahydrate (total 1.2M) and 50 g/L anhydrous sodium sulfate adjusted to the above mixing ratio, the deposition amount It was formed by adjusting the plating time so that it might become the value shown in this table.

<Zn-Co-Mo plating film (No. 60 to 61)>

The mixing ratio of Zn sulfate heptahydrate, Co sulfate heptahydrate and sodium molybdate dihydrate was adjusted so that when plating was performed at a bath temperature of 50° C. and a current density of 50 A/dm2, the composition described in the column of “Plating species” in the table was obtained. A plating bath of pH 4.0 containing Zn sulfate heptahydrate, Co sulfate heptahydrate and sodium molybdate dihydrate (total 1.2M), 25 g/L sodium formate, and 50 g/L boric acid adjusted to the above mixing ratio It was formed by adjusting the plating time so that the adhesion amount became the value shown in the table.

The plating solution was flowed so that the relative flow rate was 1 m/sec during all the plating treatments.

<Measurement of composition of plating film>

The composition of the obtained plating film was confirmed by immersing the plated steel sheet in 10 mass % hydrochloric acid containing an inhibitor (NO. 700AS manufactured by Asahi Chemical) to dissolve and peel, and analyze the dissolved solution by ICP.

All of the above reagents used general reagents.

<Formation of hairline>

With respect to the obtained plated steel sheet, a hairline was provided along the L direction (rolling direction) of the steel sheet. The hairline was formed by pressing abrasive paper against the steel plate. A hairline was formed by adjusting the particle size of the abrasive paper, the reduction force, and the number of times of polishing to achieve the polishing/grinding rate described in the table.

In addition, the polishing/grinding rate was determined by obtaining the respective plating adhesion amount without applying a hairline to one of the two 100 mm width adjacent places in the width direction of the steel sheet and not providing a hairline to the other side, and the plating adhesion amount before the hairline application It computed from the difference of the adhesion amount after provision of the other hairline. In addition, the value of the plating specific gravity at this time was 7.1.

The plating roughness and plating adhesion amount after hairline provision are as showing in a table|surface.

<Measurement of surface roughness Ra>

The surface roughness Ra of the steel sheet after removing the plating layer is measured with a three-dimensional surface roughness meter (Surfcom 1500DX3 manufactured by Tokyo Seimitsu), and the three-dimensional surface roughness Sa of the plated steel sheet has a display resolution in the height direction of 1 nm or more, Moreover, it measured according to the said method using the laser microscope /VK-9710 by the Keyence company whose display resolution of the width direction is 1 nm or more.

<Measurement of adhesion amount of plating layer before hairline application>

The amount of plating adhesion before hairline application was calculated from the weight difference before and after dissolving and peeling the steel sheet after forming the plating layer by immersing it in 10 mass % hydrochloric acid containing an inhibitor (NO. 700AS manufactured by Asahi Chemical).

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<Measurement of R50>

The three-dimensional average surface roughness Sa (50 µm) of a region of 50 µm×50 µm was successively measured at 21 points in the hairline direction and 21 points in the hairline direction orthogonal direction, respectively. The ratio R50 of three-dimensional average surface roughness Sa (50 micrometers) in an adjacent area|region was computed in the adjacent area|region of a total of 20. Among the total of 20 adjacent regions, the ratio of the numbers occupied by the adjacent regions A having R50 of less than 0.667 or 1.500 or more was described in each table.

<Measurement of adhesion amount of plating layer after hairline application>

The measurement of the adhesion amount of the plating layer after hairline provision was performed similarly to the measurement of the adhesion amount of the plating layer before hairline provision.

Here, the difference in the adhesion amount of the plating layer before and behind hairline provision corresponds to the decrease of the plating layer in the process of providing a hairline.

<Measurement of iron exposure rate>

The plated steel sheet obtained by the above-mentioned manufacturing method was cut out, and the image was analyzed by EPMA (JXA8230 by a Nippon Electronics Co., Ltd.) at 5 sights of a rectangle with a side of 1 mm. A region in which Zn was not detected and Fe was detected by image analysis was considered to be exposed to ferrous iron, and the area ratio of the region was defined as the ferrous exposure ratio. The EPMA analysis was performed under the conditions of an acceleration voltage of 15 kV and an irradiation current of 30 ㎁. When it is determined that Zn is not detected in a region where the detection intensity of Zn is 1/16 or less when a standard sample (pure Zn) is measured, and the detection intensity of Fe is measured in a standard sample (pure Fe) It was judged that Fe was detected in the region exceeding 14/16.

These results obtained are shown in the table.

<Formation of organic resin coating layer>

A transparent organic resin coating layer was formed on the plated steel sheet to which the hairline was applied. As the processing liquid for forming the organic resin, various concentrations and viscosities in which a urethane-based resin (manufactured by ADEKA, Inc., HUX-232) were dispersed in water were used. The treatment liquid was scooped up with a roll and transferred to a plated steel sheet so as to have a thickness shown in the table after baking and drying. The plated steel sheet to which the treatment liquid was transferred was placed in a furnace maintained at 250° C., maintained for 1 to 5 minutes until the reached temperature of the steel sheet reached 210° C., and then taken out and cooled. Also, No. For 62 to 69, carbon black (manufactured by Mitsubishi Chemical: #850) and cyanine blue (manufactured by Dainichi Seika Kogyo: AF Blue E-2B) were added as colorants to the organic resin film layer.

<Adjustment of processing liquid for organic resin formation>

By adding BYK-425 (manufactured by Big Chemie) as a viscosity modifier to the processing liquid for organic resin formation, it has a viscosity of 10 [Pa·s] or more at a shear rate of 0.1 [1/sec], and at a shear rate of 1000 [1/sec] It was adjusted to have a shear viscosity of 0.01 [Pa·s] or less. Moreover, the viscosity modifier was not added only to the processing liquid corresponding to conditions 6, 9, 25, 39, 53, and it adjusted so that the viscosity in a shear rate of 0.1 [1/sec] might be less than 10 [Pa*s].

<Measurement of surface roughness Ra (CC) of organic resin coating layer>

The surface roughness Ra (CC) of the organic resin coating layer was measured with a three-dimensional surface roughness measuring device (Surfcom 1500DX3 manufactured by Tokyo Seimitsu) similarly to the measurement of the surface roughness Ra of the steel sheet after removing the plating layer.

<Measurement of glossiness>

The 60° glossiness G60 of the plated steel sheet after formation of the organic resin coating layer was measured by a gloss meter (manufactured by Suga Shikenki: Gloss Meter UGV-6P) in the L direction (rolling direction of the steel sheet) and C direction (direction perpendicular to the rolling direction) was measured in each of the The obtained values of G60 are shown in the table.

When the glossiness G60 (Gl) measured in the hairline direction (in the sample used, the hairline is formed along the L direction, indicating the same direction as the L direction) was 70 or more and 150 or less, it was judged that proper gloss was obtained. .

<Evaluation of light transmittance>

The light transmittance of the zinc-based electroplated steel sheet after formation of the organic resin coating layer was evaluated by the following method.

The zinc-based electroplated steel sheet after the formation of the organic resin coating layer was exposed to light from a fluorescent lamp from an angle of 45° and observed from a distance of 15 cm at an angle of 10° from the vertical direction to the steel sheet, and the light transmittance was evaluated according to the following evaluation criteria. What was evaluated as A or B was set as the pass. The results obtained are shown in the table.

(Evaluation standard)

A: A hairline with a length of 20 mm or more can be clearly recognized

B: A hairline of 20 mm or more in length with an unclear outline can be visually recognized

C: A hairline of 20 mm or more cannot be visually recognized

D: I can't see the hairline at all

<Evaluation of film adhesion>

The film adhesiveness of the zinc-based electroplated steel sheet after formation of the organic resin coating layer was evaluated by the following method.

A test piece having a width of 50 mm and a length of 50 mm was produced from the zinc-based electroplated steel sheet after the formation of the organic resin coating layer. After bending at 180 degrees with respect to the obtained test piece, the tape peeling test was implemented with respect to the outer side of a bent part. The external appearance of the tape peeling part was observed with a magnifying glass having a magnification of 10 times and evaluated according to the following evaluation criteria. The bending process was performed by pinching|interposing a 0.5 mm spacer in a 20 degreeC atmosphere. What was evaluated as A or B was set as the pass. The results obtained are shown in the table.

Also, No. In SUS, since the organic resin coating layer was not formed, film adhesiveness was not evaluated. Because of that, No. The evaluation result of the film adhesiveness of SUS is shown with "-".

(Evaluation standard)

A: Peeling of the organic resin coating layer and/or the zinc-based electroplating layer was not confirmed on the adhesive side of the tape.

B: Peeling of the organic resin coating layer and/or the zinc-based electroplating layer was confirmed in a very small portion of the adhesive surface of the tape (peelable area ≤ 2%)

C: Peeling of the organic resin coating layer and/or the zinc-based electroplating layer was confirmed on a part of the adhesive surface of the tape (2% < peeling area ≤ 20%)

D: Peeling of the organic resin coating layer and/or the zinc-based electroplating layer was confirmed on the adhesive side of the tape (peelable area > 20%)

<Evaluation of corrosion resistance>

When evaluating the corrosion resistance (more specifically, long-term corrosion resistance) of the zinc-based electroplated steel sheet after the formation of the organic resin coating layer, the obtained sample was first cut into a size of 75 mm × 100 mm, and the end surface and the back surface were protected with a tape seal. A sample with one side and a back side protected by a tape seal was subjected to a salt spray test of 35° C.-5% NaCl (JIS Z 2371:2015). The sample whose rust occurrence rate after 240 hours was 5 % or less was OK, and the sample which exceeded 5 % was NG. The results obtained are shown in the table.

<Evaluation of metallic feeling>

The following method evaluated the metallic feeling of the zinc-based electroplated steel sheet after formation of the organic resin coating layer.

The values of glossiness G60 (Gl) measured in the hairline direction and G60 (Gc) measured in the direction perpendicular to the hairline, and CIE standard light source D65 conditions using a spectrophotometer (manufactured by Konica Minolta: CM-2600d) L ^* a ^* b ^* Using the values of a ^* and b ^* measured by the SCE (Specula Component Excluded: specular light removal) method for color tone by the color system, the metallic feeling was evaluated according to the following evaluation criteria. What was evaluated as A or B was set as the pass. The results obtained are shown in the table.

(Evaluation standard)

A: 0.3≤Gc/Gl≤0.75 Also (a ^*2 +b ^*2 ) ^0.5 ≤5

B: 0.3≤Gc/Gl≤0.85 Also 5<(a ^*2 +b ^*2 ) ^0.5 ≤10, or 0.75<Gc/Gl≤0.85 Also (a ^*2 +b ^*2 ) ^0.5 ≤10

C: 0.3>Gc/Gl, or Gc/Gl>0.85, or 10<(a ^*2 +b ^*2 ) ^0.5

As is clear from Tables 1 to 6, it can be seen that the zinc-based electroplated steel sheet according to the embodiment of the present invention has excellent light transmittance, moderate glossiness, and excellent metallic feeling and film adhesion. On the other hand, in the zinc-based electroplated steel sheet corresponding to the comparative example of the present invention, excellent results were not obtained with respect to at least any one of light transmission properties, glossiness, metallic feeling, and film adhesion.

As mentioned above, although preferred embodiment of this invention was described in detail, referring an accompanying drawing, this invention is not limited to this example. It is clear that those of ordinary skill in the art to which the present invention pertains can imagine various changes or modifications within the scope of the technical idea described in the claims, It is understood to belong to the technical scope of the invention.

1: Zinc-based electroplated steel sheet
11: grater
13: zinc-based electroplating layer
15: organic resin coating layer
101a, 101b: grandfather
103: smooth part

Claims (9)

steel plate;
a zinc-based electroplating layer disposed on at least one surface of the steel sheet and having a hairline extending in a predetermined direction on the surface;
provided,
In the zinc-based electroplating layer, three-dimensional average surface roughness Sa of a region of 50 μm×50 μm along each of the hairline direction in which the hairline is stretched and the hairline orthogonal direction perpendicular to the hairline direction (50 μm) is successively measured to calculate R50, which is the ratio of the Sa (50 μm) in the adjacent region formed by the two neighboring regions, and adjacent the adjacent region in which the R50 is less than 0.667 or greater than or equal to 1.500 In the case of region A, the proportion of the number of adjacent regions A is 30% or more in either the hairline direction and the hairline orthogonal direction.
A zinc-based electroplated steel sheet, characterized in that. According to claim 1,
As an upper layer of the zinc-based electroplating layer, further comprising an organic resin coating layer having light-transmitting properties and having a thickness of 10 µm or less.
A zinc-based electroplated steel sheet, characterized in that. 3. The method of claim 2,
The organic resin coating layer contains a colorant,
When the color tone by the L ^* a ^* b ^* colorimetric system of the organic resin coating layer was measured by the specular light removal method using a colorimeter using the CIE standard light source D65, (a ^*2 +b ^*2 ) ^0.5 where the value of is less than or equal to 10
A zinc-based electroplated steel sheet, characterized in that. 4. The method of claim 2 or 3,
In the state in which the organic resin coating layer is present, the surface roughness Ra (CC) measured along the direction perpendicular to the hairline, and the surface roughness Ra (CC) measured along the direction perpendicular to the hairline after the organic resin coating layer is peeled off When the surface roughness Ra (MC) of the linked electroplating layer satisfies the relationship expressed by the following formula (1),
A zinc-based electroplated steel sheet, characterized in that.
Ra(CC)<Ra(MC)<5×Ra(CC) . . . Equation (1) 4. The method according to any one of claims 1 to 3,
When the iron exposure rate of the zinc-based electroplating layer is less than 5%
A zinc-based electroplated steel sheet, characterized in that. 4. The method according to any one of claims 1 to 3,
The adhesion amount of the zinc-based electroplating layer is 10 g/m 2 to 60 g/m 2
A zinc-based electroplated steel sheet, characterized in that. 4. The method according to any one of claims 1 to 3,
The surface roughness Ra of the steel sheet after removing both the zinc-based electroplating layer or the organic resin coating layer provided as an upper layer of the zinc-based electroplating layer and the zinc-based electroplating layer is 1.0 µm or more and 1.7 µm or less
A zinc-based electroplated steel sheet, characterized in that. 4. The method according to any one of claims 1 to 3,
wherein the zinc-based electroplating layer contains 5% to 20% by mass in total of any one or more elements selected from the group consisting of Fe, Ni and Co.
A zinc-based electroplated steel sheet, characterized in that. 4. The method according to any one of claims 1 to 3,
The surface roughness Ra of the steel sheet after removing both the zinc-based electroplating layer or the organic resin coating layer provided as an upper layer of the zinc-based electroplating layer and the zinc-based electroplating layer is 60% or less of the thickness of the zinc-based electroplating layer
A zinc-based electroplated steel sheet, characterized in that.

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