JP2004190096A - Composite roughened steel sheet, and production method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roughened steel sheet which has high adhesion with a resin film in a plain steel or a special steel at a low cost. <P>SOLUTION: In the composite roughened steel sheet, first ruggedness by dull roll rolling is formed on the surface of a steel sheet comprising, by mass, ≤3.5% Cr, ≤5.0% Ni and ≤1.0% Mo, and second ruggedness having a reduced pitch by etching is formed on the ruggedness. In particular, the one in which Ra measured in a rolling direction is 0.4 to 2.0 μm, or Ra is 0.6 to 1.5 μm and also Ry is 5.0 to 15.0 μm is provided. The composite roughened steel sheet is produced by a method where the first ruggedness having Ra of ≥0.4 μm (e.g., 0.6 to 1.5 μm) is formed by dull roll rolling, thereafter, the steel sheet is dipped into a hydrochloric acid aqueous solution in which the concentration of hydrochloric acid lies in the range of 50 to 150 g/L, and the temperature lies in the range of 60 to 95°C for one or more times so that the total dipping time reaches 25 to 600 s, and the second ruggedness having a reduced pitch is formed on the first ruggedness. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２７】
鋼板Ａ〜Ｃから複数のサンプルを切り出し、それぞれ粗面化表面の上に有機高分子樹脂系接着剤（田岡化学工業(株)製「テクノダインＡＨ」）を平均厚さが10μmとなるようにほぼ均一に塗布し、以下の２通りの条件で焼付硬化処理を行った。
〔焼付条件１〕 80℃×60分
〔焼付条件２〕 100℃×65分
ここで、温度は雰囲気（大気）の温度を意味する。
【００２８】
焼付硬化処理後の一部のサンプルは沸騰水中に１時間浸漬した。
各サンプルから曲げ試験片を切り出し、3.5Ｒ−90°Ｖ曲げ試験を行ったのち、曲げ加工部について「セロハンテープ剥離試験」を実施して接着剤の密着性を評価した。
セロハンテープ剥離試験は、JIS Z 1522で定めるセロハン粘着テープを曲げ加工部の外周部に貼付した後、剥ぎ取って、接着剤皮膜の剥離状況を観察し、以下の基準で密着性を評価した。各サンプルともｎ＝３で試験を行い、最も評価の悪い試験片の結果を採用し、◎および○を合格と判定した。
〔密着性評価基準〕
◎：剥離は認められない
○：点状の剥離が認められる
△：線状に連なった剥離が認められる
×：全面剥離またはそれに近い著しい剥離が認められる
結果を表２に示す。
【００２９】
【表２】

【００３０】
表２から判るように、ダルロール仕上材である鋼板Ａは、加工部において接着剤との十分な密着性は得られなかった。これに対し、本発明例の複合粗面化鋼板である鋼板Ｂ，Ｃは、加工部においても各試験条件で接着剤との良好な密着性が維持された。Ａ〜Ｃの鋼板は中心線平均粗さに差がないにもかかわらず、樹脂皮膜との密着性に大きな差が生じた。これは、本発明の複合粗面化鋼板における特異な表面凹凸の形態が、アンカー効果の増大に寄与したものと考えられる。
【００３１】
【発明の効果】
以上のように、本発明では電解粗面化が難しい普通鋼や特殊鋼において、２種類の凹凸が複合した特異な粗面化表面の形成を可能にした。この複合粗面化鋼板は特に有機高分子樹脂皮膜との密着性が従来のダルロール仕上材などに比べ顕著に向上した。しかも、その製造は、一般的な鋼板製造ラインを利用して比較的簡単に実施することができる。したがって、本発明は、鋼板表面への各種樹脂コーティングの適用性を高め、特に接着接合の用途においては接合力の向上をもたらすものである。
【図面の簡単な説明】
【図１】(ａ)は本発明に係る複合粗面化鋼板の表面を圧延方向に測定した粗さ曲線を示したもの、(ｂ)はその途中工程であるダルロール圧延後の鋼板表面を圧延方向に測定した粗さ曲線を示したものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a composite surface-roughened steel sheet having complex irregularities formed on a steel sheet surface by dull roll rolling and etching, and a method for producing the same.
[0002]
[Prior art]
Generally, the surface of a steel sheet material is often plated from the viewpoint of rust prevention and coating film adhesion, but depending on the application, it is necessary to apply a paint or adhesive directly on the steel sheet base without using a plating layer. May occur.
[0003]
In recent years, there has been an improvement in the performance of adhesives, and when manufacturing various structures, a method of joining steel sheets to each other or to a steel sheet and a dissimilar material using an adhesive has come to be used frequently. Such a bonding method has advantages such as no welding distortion, improved sealability, reduced weight, and improved workability. For example, it accommodates important equipment such as industrial computers and various control panels. It is used for a wide range of applications, such as housings that can be used, doors for railway vehicles, building materials such as roofs and exteriors, wall panels for elevators, ducts, and system kitchens. Further, “laminated parts” and “laminated dies” are manufactured by punching a steel sheet into a predetermined shape based on three-dimensional data, laminating and bonding.
[0004]
As an application for bonding a steel sheet and a dissimilar material, for example, there is a friction plate which is a component of an automatic transmission of an automobile. This is a friction material (for example, a composite obtained by impregnating a fibrous base material with a filler or a resin binder and heating and curing) on the surface of a core material (steel plate). It constitutes a plate. Another example is a laminated rubber isolator that supports buildings with seismic isolation structures. This is made by laminating and bonding natural rubber and steel plate, and acts as a seismic isolation mechanism between the building and the ground.
[0005]
Generally, a steel sheet base material has not very good adhesion to a coating film such as an organic polymer resin or an adhesive. For this reason, when a paint or an adhesive is applied directly to a steel sheet substrate, a problem that the coating film is peeled off by bending or drawing or that the material joined via the adhesive is peeled off by external stress is likely to occur. . Therefore, the surface of the steel sheet may be roughened as a pretreatment. Typical means include blasting and dull roll rolling.
[0006]
Blasting is a roughening means in which abrasive particles such as chutes and grids are sent out with high-pressure air to collide with the surface of a steel sheet to be roughened, and the collision causes the steel sheet surface to be shaved to form an uneven shape. However, the processing of the scraped steel powder reduces continuous productivity, and particularly in the case of a thin gauge steel sheet, a shape defect such as warping of the sheet is likely to occur. Another drawback is that the surface roughness tends to fluctuate depending on the type of abrasive particles, air pressure and other conditions.
[0007]
Dull roll rolling is a roughening means for transferring the unevenness formed on the surface of the rolling roll to the surface of the steel sheet, and the surface roughness can be controlled to some extent. However, it is difficult to roughen the surface to greatly improve the adhesion to the organic polymer resin film.
[0008]
On the other hand, as a surface roughening technique for stainless steel, an electrolytic surface roughening method has been developed. For example, Patent Document 1 listed below discloses a surface roughening method in which anodic electrolysis or anodic electrolysis + cathodic electrolysis of stainless steel is performed in nitric acid or an aqueous solution containing nitric acid as a main component. Patent Literature 2 discloses a method in which a stainless steel plate is alternately electrolyzed in an aqueous ferric chloride solution to form pits having a unique shape with a high anchor effect at a high density. These all utilize the property that stainless steel easily forms a passive film. That is, since the corrosion form of stainless steel is apt to be pitting in nature, a rough surface having a high anchor effect can be relatively easily formed by using this property skillfully.
[0009]
On the other hand, it is not always easy to roughen ordinary steel or special steel other than stainless steel by electrolysis or etching. Since these steels have a low Cr content and are more likely to dissolve over the entire surface than pitting corrosion, it is inherently difficult to form pits with high density. For this reason, large costs are required to industrially produce a roughened steel sheet having a high anchor effect by electrolysis or etching.
[0010]
[Patent Document 1]
JP-A-6-136600 [Patent Document 2]
JP-A-10-259499
[Problems to be solved by the invention]
The present invention is a roughened steel sheet having excellent adhesion with an adhesive or a paint on a steel sheet of ordinary steel or special steel other than stainless steel, and produced at low cost by using general steel sheet manufacturing equipment. It is an object of the present invention to provide a surface-roughened steel sheet that can be easily manufactured.
[0012]
[Means for Solving the Problems]
The inventors have conducted various studies and found that by combining dull roll rolling and etching, it is possible to form a roughened surface with excellent adhesion to organic polymer resin films such as adhesives, even on plain steel. Was found. As described above, the anchor effect on the organic polymer resin film cannot be sufficiently obtained only by dull roll rolling. On the other hand, it is difficult to form deep pits at a high density on the surface of ordinary steel by etching immersed in acid or salt, and it is therefore difficult to industrially realize roughening with a high anchoring effect at low cost. . However, when dull roll rolling and etching are combined under appropriate conditions, it is possible to form small irregularities by etching on large irregularities by dull roll, and this new form of roughened surface is applied to the organic polymer resin film. It has been found that they exhibit an excellent anchor effect. Moreover, the etching step can be easily performed using a general pickling line. The present invention has been completed based on these findings.
[0013]
That is, the above-mentioned object is to form first unevenness by dull roll rolling on a steel sheet surface of not more than 3.5% by mass of Cr, not more than 5.0% by mass of Ni, and not more than 1.0% by mass of Mo and etching on the unevenness (for example, hydrochloric acid aqueous solution). This is achieved by a composite roughened steel sheet in which second irregularities having a small pitch are formed by etching (immersion in a steel plate).
In the present specification, a steel sheet having a unique roughened surface formed by superimposing such large unevenness (first unevenness) and small unevenness (second unevenness) is referred to as “composite roughened steel sheet”. I have. When a roughness curve defined in JIS B 0601 is measured in a direction parallel to the rolling direction, a characteristic roughened form in which the first unevenness and the second unevenness are superimposed can be grasped from the profile.
[0014]
As the composite roughened steel sheet, a steel sheet having a center line average roughness Ra measured in the rolling direction of 0.4 to 2.0 μm is provided. In addition, there is provided one having a center line average roughness Ra measured in the rolling direction of 0.6 to 1.5 μm and a maximum height Ry of 5.0 to 15.0 μm. Here, Ra and Ry are specified in JIS B 0601.
These composite roughened steel sheets are particularly suitable for applications in which an organic polymer resin-based adhesive is applied to the surface.
[0015]
Further, the first irregularities having a center line average roughness Ra of 0.4 μm or more measured in the rolling direction by subjecting a steel sheet having Cr: 3.5% by mass or less, Ni: 5.0% by mass or less, and Mo: 1.0% by mass or less to roll rolling. Is formed, and then dipped in a hydrochloric acid aqueous solution to form a second roughened steel sheet having a small pitch on the first unevenness.
Further, the steel plate having the above composition is subjected to dull roll rolling to form first irregularities having a center line average roughness Ra of 0.6 to 1.5 μm measured in the rolling direction, and then a hydrochloric acid concentration of 50 to 150 g / L (liter) and a temperature of A composite rough formed by immersing once or plural times in a hydrochloric acid aqueous solution in a range of 60 to 95 ° C. so as to have a total immersion time of 25 to 600 seconds to form second pitch unevenness on the first unevenness. A method for manufacturing a surfaced steel sheet is provided.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1A shows an example of a roughness curve obtained by measuring the surface of the composite roughened steel sheet according to the present invention in the rolling direction. This steel sheet is a cold-rolled annealed steel sheet containing, by mass%, C: 0.11%, Si: 0.01%, Mn: 0.31%, P: 0.018%, and S: 0.008%, with the balance being Fe and unavoidable impurities. (Plate thickness: 1.0 mm), this was subjected to 10% dull roll rolling, and then immersed in a hydrochloric acid aqueous solution having a concentration of 100 g / L and a temperature of 90 ° C. for 60 seconds for etching. FIG. 1B is a roughness curve obtained by measuring the surface of the steel sheet of FIG. 1A in the rolling direction at the time when dull roll rolling, which is in the middle of manufacturing the steel sheet, is completed (before etching).
[0017]
In the composite roughened steel sheet of FIG. 1 (a), irregularities (second irregularities) having a small pitch are formed on the irregularities (first irregularities) by dull roll rolling shown in FIG. 1 (b). You can see the situation. That is, fine “jaggies” by etching are added while leaving the “undulations” of the irregularities formed by dull roll rolling. The roughened surface having such complex concavo-convex can significantly improve the adhesion of the organic polymer resin film as compared to a surface as-rolled as a dull roll or a mere pickled surface. Although the mechanism of the improvement in the adhesion is still inferred, the basic adhesive force is improved by increasing the contact area with the resin due to the second fine unevenness, and the first large unevenness. It is considered that a higher anchor effect is consequently exhibited by improving the ability to receive the external force applied to the resin film.
[0018]
The present invention is intended for steel types with Cr: 3.5% by mass or less, Ni: 5.0% by mass or less, and Mo: 1.0% by mass or less. This range includes various types of ordinary steel and special steel, but since these do not form a strong passive film unlike stainless steel, they are essentially difficult to roughen by electrolysis or etching.
[0019]
Specific target steels include, for example, the following steel types.
i) In mass%, C: 0.32 to 0.38%, Si: 0.15 to 0.35%, Mn: 0.60 to 0.90%,
P: 0.030% or less, S: 0.035% or less, balance Fe and inevitable impurities.
ii) In mass%, C: 0.52 to 0.58%, Si: 0.15 to 0.35%, Mn: 0.60 to 0.90%,
P: 0.030% or less, S: 0.035% or less, balance Fe and inevitable impurities.
iii) In mass%, C: 0.17 to 0.20%, Si: 0.04% or less, Mn: 0.60 to 0.90%,
P: 0.030% or less, S: 0.025% or less, balance Fe and inevitable impurities.
iv) In mass%, C: 0.10 to 0.15%, Si: 0.04% or less, Mn: 0.30 to 0.50%, P: 0.025% or less, S: 0.025% or less, balance Fe and inevitable impurities.
[0020]
Dull roll rolling is an essential step for forming the first irregularities. In the present invention, the process of manufacturing a usual dull finish can be used as it is. If only one side of the steel sheet is roughened, a dull roll may be used only on that side. In order to finally achieve high adhesion to the organic polymer resin film, it is desirable to perform dull roll rolling so that the center line average roughness Ra measured in the rolling direction is 0.4 μm or more. However, since it is technically difficult to form too large irregularities by dull roll rolling, the upper limit of Ra is preferably about 2.0 μm. In consideration of the adhesion to the resin film and the manufacturability, it is efficient to form irregularities with Ra of 0.6 to 1.5 μm by dull roll rolling.
[0021]
The roll ratio of dull roll rolling is not particularly limited as long as the first irregularities exhibiting the Ra value as described above are formed. Although it depends on the sheet thickness and the degree of working before dull roll rolling, for example, when dull roll rolling is performed on a cold rolled annealed steel sheet having a sheet thickness of about 0.8 to 3.0 mm, a rolling rate of about 8 to 60% is preferably used. .
[0022]
After the first unevenness is formed by dull roll rolling, the second unevenness is formed by etching. At this time, it is necessary to form the second unevenness having a small pitch so as to overlap with the “undulation” while leaving the “undulation” of the first unevenness.
According to studies by the inventors, it has been found that such second irregularities can be formed by etching immersed in an aqueous solution of “hydrochloric acid”. It was impossible with an aqueous solution of “sulfuric acid”.
[0023]
For example, an aqueous hydrochloric acid solution having a hydrochloric acid concentration of 50 to 150 g / L and a temperature of 60 to 95 ° C can be used. The immersion time may be adjusted in the range of 25 to 300 seconds. The number of times of immersion may be one, but it was confirmed that immersion may be performed in a plurality of times. In that case, the total immersion time is adjusted in the range of 25 to 300 seconds. The etching with hydrochloric acid has an advantage that a continuous pickling line of a steel maker can be used.
[0024]
As a result of various experiments, it was found that the Ra value did not change much between the stage after dull roll rolling and the stage after etching. In the final composite roughened steel sheet, Ra measured in the rolling direction is desirably 0.4 to 2.0 μm. Further, those having Ra measured in the rolling direction of 0.6 to 1.5 μm and Ry of 5.0 to 15.0 μm are excellent in the balance between the adhesion to an organic polymer resin film, particularly an adhesive, and the production cost.
[0025]
【Example】
Cold-rolled annealed steel strip of steel containing 0.18% by mass, Si: 0.01%, Mn: 0.63%, P: 0.018%, S: 0.003%, and the balance being Fe and unavoidable impurities. This was subjected to about 10% dull roll rolling using 0.9 mm). After the steel strip was degreased, a comparative steel sheet having a dull roll finish was cut out and used as a steel sheet A. The remaining part of the steel strip was divided into two to prepare two steel strips. Samples were cut out from the steel sheet A and the two steel strips and the surface roughness was measured. As a result, Ra after dull roll rolling was 1.2 μm.
The two steel strips were passed through a continuous pickling line consisting of four tanks, and etched by immersion in hydrochloric acid. The total immersion time was changed by changing the respective passing speeds to obtain the steel sheets B and C as the composite roughened steel sheets of the present invention.
Table 1 shows the etching conditions and the surface roughness of the steel sheets A to C (Ra and Ry measured in the rolling direction).
[0026]
[Table 1]

[0027]
A plurality of samples were cut out from the steel sheets A to C, and an organic polymer resin-based adhesive (“Technodine AH” manufactured by Taoka Chemical Industry Co., Ltd.) was applied on each of the roughened surfaces so that the average thickness became 10 μm. The coating was performed almost uniformly, and a bake hardening treatment was performed under the following two conditions.
[Baking condition 1] 80 ° C. × 60 minutes [Baking condition 2] 100 ° C. × 65 minutes Here, the temperature means the temperature of the atmosphere (atmosphere).
[0028]
Some of the samples after the bake hardening treatment were immersed in boiling water for 1 hour.
After bending test pieces were cut out from each sample and subjected to a 3.5R-90 ° V bending test, a “cellophane tape peeling test” was performed on the bent portion to evaluate the adhesiveness of the adhesive.
In the cellophane tape peeling test, a cellophane adhesive tape specified in JIS Z 1522 was adhered to the outer peripheral portion of the bent portion, then peeled off, the state of peeling of the adhesive film was observed, and the adhesion was evaluated according to the following criteria. Each sample was tested at n = 3, and the result of the test piece with the worst evaluation was adopted.
(Adhesion evaluation criteria)
：: No peeling was observed. 点: Point-like peeling was observed. △: Linear continuous peeling was observed. X: Total peeling or significant peeling similar thereto was observed.
[0029]
[Table 2]

[0030]
As can be seen from Table 2, the steel plate A, which is a dull roll finishing material, did not have sufficient adhesiveness with the adhesive in the processed portion. On the other hand, the steel sheets B and C, which are the composite roughened steel sheets of the present invention, maintained good adhesion to the adhesive under the respective test conditions even in the processed part. Although the steel sheets A to C had no difference in the center line average roughness, there was a large difference in the adhesion to the resin film. This is presumably because the form of the unique surface irregularities in the composite roughened steel sheet of the present invention contributed to an increase in the anchor effect.
[0031]
【The invention's effect】
As described above, in the present invention, it is possible to form a peculiar roughened surface in which two types of irregularities are combined in ordinary steel and special steel in which electrolytic surface roughening is difficult. This composite-roughened steel sheet has remarkably improved adhesiveness particularly to the organic polymer resin film as compared with a conventional dull roll finish. Moreover, the production can be performed relatively easily using a general steel sheet production line. Therefore, the present invention enhances the applicability of various resin coatings to the surface of a steel sheet, and particularly improves the bonding strength in the application of adhesive bonding.
[Brief description of the drawings]
FIG. 1 (a) shows a roughness curve obtained by measuring the surface of the composite roughened steel sheet according to the present invention in the rolling direction, and FIG. 1 (b) shows the rolling of the steel sheet surface after dull roll rolling, which is an intermediate step. 3 shows a roughness curve measured in the direction.

Claims (7)

First irregularities formed by dull roll rolling and second irregularities having a small pitch formed by etching are formed on the surface of a steel sheet having Cr: 3.5% by mass or less, Ni: 5.0% by mass or less, and Mo: 1.0% by mass or less. Composite roughened steel sheet. The composite roughened steel sheet according to claim 1, wherein the second irregularities are formed by etching by immersion in hydrochloric acid. The composite roughened steel sheet according to claim 1 or 2, wherein the center line average roughness Ra measured in the rolling direction is 0.4 to 2.0 µm. The composite roughened steel sheet according to claim 1 or 2, wherein the center line average roughness Ra measured in the rolling direction is 0.6 to 1.5 µm, and the maximum height Ry is 5.0 to 15.0 µm. The composite roughened steel sheet according to any one of claims 1 to 4, which is used by applying an organic polymer resin-based adhesive to the surface. First roll of 3.5% by mass or less, Ni: 5.0% by mass or less, Mo: 1.0% by mass or less subjected to dull roll rolling to form first irregularities having a center line average roughness Ra of 0.4 μm or more measured in the rolling direction. And then immersing in a hydrochloric acid aqueous solution to form second unevenness having a small pitch on the first unevenness. Cr: 3.5 mass% or less, Ni: 5.0 mass% or less, Mo: 1.0 mass% or less. After the formation, it is immersed once or plural times in an aqueous hydrochloric acid solution having a hydrochloric acid concentration of 50 to 150 g / L and a temperature of 60 to 95 ° C. so that the total immersion time is 25 to 600 seconds, and the first unevenness is formed. A method for producing a composite roughened steel sheet in which second irregularities having a small pitch are formed.

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