JPWO2013176219A1 - Al-based alloy plated steel with hairline appearance - Google Patents

Abstract

The Al-based alloy-plated steel material of the present invention is an Al-based alloy-plated steel material having a hairline appearance in which a hairline is formed on the surface of a plating layer composed of Si and the remaining Al and impurities, wherein the plating layer is The adhesion amount per one side of the plating layer is 20 to 100 g / m 2; the Si content of the entire plating layer is 5 to 12% by mass; and the maximum Si content in the region of 2 μm thickness of the surface layer of the plating layer is And the hairline has a surface roughness Ra in the direction perpendicular to the hairline of 0.3 to 2.0 μm; a PPI of a reference level of 300 μin is 0; a PPI of a reference level of 200 μin is less than 10; PPI at level 30 μin is 50 or more.

Description

The present invention relates to an Al-based alloy-plated steel material having a hairline appearance that is used for a surface layer material of an electric device, an interior material or an exterior material of a building or a vehicle.
This application claims priority on May 23, 2012 based on Japanese Patent Application No. 2012-117284 for which it applied to Japan, and uses the content for it here.

Stainless steel materials are well known as steel materials having a conventional hairline appearance. That is, hairline finishing (HL finishing) is defined in JIS-G4305 as one of the surface finishing of stainless steel materials. In this rule, hairline finish is defined as “finished with an abrasive of an appropriate particle size so that a continuous polish can be made”. Means finishing. FIG. 1 is a diagram showing an outline of hairline finishing.

  As shown in FIG. 1, the normal hairline finishing method is such that the endless paper polishing belt 3 stretched between the contact wheel 1 and the idle roll 2 is rotated at a high speed by rotating the contact wheel 1, and the uncoiler 4 to the coiler 5 are rotated. It is well known that this is a processing method in which the surface of the metal band 6 that moves to the surface is polished with a polishing belt (see, for example, Patent Documents 1 and 2). Stainless steel materials with a hairline finish are corrosion resistant and have a unique surface pattern, so they are widely used as surface materials for electrical equipment, interior materials and exterior materials for building materials where design is important.

  However, since stainless steel is expensive, it is a new inexpensive material that replaces stainless steel, and has the same high design and corrosion resistance as stainless steel, and is suitable for use in electrical equipment and building materials. The steel material which has is desired.

  Therefore, the inventor paid attention to an Al-based alloy-plated steel material that is excellent in corrosion resistance and inexpensive as in the case of the stainless steel material, and studied to apply a hairline finish thereto.

  As a conventional technique for applying a hairline finish to a plating layer, if a plating coating layer is formed on the surface of a lightweight Mg-based member and a hairline pattern is formed on the surface of the plating coating layer by hairline finishing, the base of the plating coating layer is There has been proposed a technique that solves the problem that the corrosion resistance is deteriorated and the high quality member cannot be stably obtained. That is, the plating coating layer (1) selected from Cu, Cu alloy, Au, Au alloy, Al, and Al alloy, formed on the surface of the Mg-based component by the dry plating method, and the plating coating layer (1) Furthermore, it has a plating coating layer (2) selected from Cu, Ni, Au, Cr, Zn, Pa, Pt, Rh, Fe, Co, Sn, Cd, Ru, and alloys thereof formed by a wet plating method. This is a technique for applying a hairline finish to the surface of an Mg-based component (see, for example, Patent Document 3). However, this technique requires that a thick plating coating layer be provided in duplicate, and it is necessary to combine dry plating and wet plating, so this technique can be applied to Al-based alloy-plated steel as it is. It is difficult.

  Moreover, although the technique of the hairline external appearance about a highly corrosion-resistant Zn type plated steel plate is also proposed, it has not reached the high-quality design property like a stainless steel material (for example, refer patent document 4, 5).

Japanese Laid-Open Patent Publication No. 1-306162 Japanese Patent No. 2055570 Japanese Patent No. 3934810 Japanese Patent No. 4546848 Japanese Patent No. 4757608

An object of the present invention is to provide an Al-based alloy-plated steel material having a hairline appearance that can be similarly applied to the same use as that of a stainless steel material having a hairline appearance.

The present invention employs the following means in order to solve the above problems and achieve the object. That is,
(1) An Al-based alloy-plated steel material having a hairline appearance according to an aspect of the present invention is an Al-based alloy plating having a hairline appearance in which a hairline is formed on the surface of a plating layer composed of Si, the remaining Al and impurities. It is steel, Comprising: As for the said plating layer, the adhesion amount per one side of the said plating layer is 20-100 g / m < ² >; Content of the said Si of the said whole plating layer is 5-12 mass%; Surface layer of the said plating layer The maximum Si content in the region of 2 μm thickness is 12 to 24% by mass; the hairline has a surface roughness Ra in the direction perpendicular to the hairline of 0.3 to 2.0 μm; 0; PPI of reference level 200 μin is less than 10; PPI of reference level 30 μin is 50 or more.

(2) In the Al-based alloy-plated steel material having the hairline appearance described in (1) above, when the surface roughness Ra in the direction perpendicular to the hairline is 0.3 to 1.0 μm, the PPI at the reference level of 300 μin is 0; The PPI of the reference level 200 μin is 0; the PPI of the reference level 100 μin is less than 10; the PPI of the reference level 30 μin is 50 or more;

(3) The Al-based alloy-plated steel material having the hairline appearance described in (1) or (2) above may have a chemical conversion treatment layer in an amount of 1 to 1000 mg / m ^{2 on} the surface of the plating layer.
(4) The Al-based alloy-plated steel material having the hairline appearance described in (1) or (2) above may have a transparent coating layer having a thickness of 0.5 to 100 μm on the surface of the plating layer.
(5) In the Al-based alloy-plated steel material having the hairline appearance described in (3) above, a transparent film layer having a thickness of 0.5 to 100 μm may be formed on the surface of the chemical conversion treatment layer.

Since the Al-based alloy-plated steel material having the hairline appearance of the above aspect has a good hairline appearance and is excellent in corrosion resistance and discoloration resistance, it can be used for the same applications as those of stainless steel materials having a conventional hairline appearance. It is possible to apply. Moreover, it can be supplied at a lower price than expensive stainless steel materials.

It is a figure which shows the outline | summary of a hairline finish. It is a figure which shows the relationship between the depth from the surface of a plating layer, and Si density | concentration.

Hereinafter, an embodiment of the present invention will be described in detail.

  As a steel material having a hairline appearance, there is a stainless steel material subjected to a hairline finish, but the stainless steel material is expensive. Then, the present inventors paid attention to the plated steel material from the viewpoint of securing corrosion resistance at a low cost. Further, the metallic feeling of the stainless steel material has a high-class feeling, but the brightness is slightly lowered. Then, Al type alloy plating was examined as a kind of plating. Al is an achromatic color with no color wrinkles and high reflectivity. Further, Al itself is an active metal, but since an extremely thin oxide film is formed, white rust does not occur immediately like Zn, for example. Therefore, the same achromatic color as that of the stainless steel material can be achieved at low cost by applying the Al-based alloy plated steel material. The reflectivity when the stainless steel material is mirror-finished is about 70%, but the reflectivity when the mirror finish of the Al-based alloy plated steel material is 75 to 90%, which is higher than that of the stainless steel material. However, a bright achromatic color can be obtained.

  Examples of the surface treatment method for the Al-based alloy-plated steel include electroplating, hot dipping, and vapor deposition. However, since Al deposits only from a non-aqueous solvent, electroplating is not industrially suitable. Moreover, vapor deposition also has a problem that the film forming speed is slow, and is not industrially suitable. The surface treatment method for the Al-based alloy-plated steel material is not particularly limited, but it is preferable to use hot dipping which is the most appropriate method in the industry.

  Next, the reason which limited the composition of the plating layer of Al system alloy plating steel materials is shown.

  When a pure Al-plated steel material containing no Si is subjected to a hairline finish equivalent to that of a stainless steel material, the hairline crests or the hairline is crushed and a hairline having a good appearance cannot be obtained, and an Al-Fe alloy layer There was also an exposed part. There is also a problem that the hairline finishing polishing belt is clogged. The reason why such a good hairline cannot be obtained is that pure Al-plated steel is soft with a Vickers hardness of about 120 Hv, and in the case of pure Al-plated steel, between the base material (steel plate) and the plating layer In particular, a hard and brittle intermetallic compound (Al—Fe alloy layer) is remarkably grown. Since Si is hard with a Vickers hardness of about 1050 Hv, the hardness of the plating layer is increased by appropriately adding Si to the plating layer. Addition up to the eutectic composition lowers the liquidus temperature of the Al—Si system and is effective in suppressing the growth of the Al—Fe alloy layer. In order to exhibit this plating layer hardness increase and Al—Fe alloy layer growth suppressing effect, the lower limit of the Si content in the entire plating layer is preferably 5% by mass.

  On the other hand, when Si is added to the plating layer, the chromaticity and lightness of the Al-based alloy-plated steel material change, and the appearance gradually becomes dull as the Si content of the plating layer increases. The reason for this is that Al—Si is a eutectic alloy. In particular, when the eutectic composition Al-12.6 mass% Si is exceeded, the primary crystal Si having a reflectance lower than that of Al crystallizes, and the brightness is significantly reduced. Can be mentioned. Furthermore, when the eutectic composition is exceeded, the liquidus temperature becomes high, and thus the growth of the Al—Fe alloy layer is promoted. For this reason, the upper limit of the Si content in the entire plating layer is preferably 12% by mass in consideration of fluctuations in actual operation. Furthermore, since the tendency of the chromaticity to shift in the blue direction due to an increase in the Si content of the plating layer was recognized from the color measurement results, the Si content in the entire plating layer should be 12% by mass. preferable.

The adhesion amount of the plating layer suitable for performing the hairline finish is preferably ²⁰ to 100 g / m ² per one side of the base material (steel material). In particular, the adhesion amount of the plating layer is more preferably 40 to 80 g / m ² per one side of the base material. When the adhesion amount of the plating layer is less than 20 g / m ² , since the plating layer is thin, the corrosion resistance is insufficient, and the steel substrate is easily exposed by hairline finishing. When the adhesion amount of the plating layer exceeds 100 g / m ² , the plating layer becomes too thick to obtain a plating layer with a uniform appearance, and the plating layer is easily peeled off, which is not preferable from the viewpoint of cost. . Therefore, the adhesion amount of the plating layer is preferably ²⁰ to 100 g / m ² .

Moreover, it is preferable that the maximum content of Si in the area | region of thickness 2 micrometers of the surface layer of a plating layer is 12-24 mass%. The reason will be described below.
In order to form a beautiful hairline on the surface of the plating layer, it is necessary to remove a solidified pattern (so-called spangle) remaining on the surface of the plating layer in the process of forming the plating layer. Therefore, before the hairline is formed, the plating layer needs to be planarized so that the surface roughness Ra of the plating layer is 0.5 μm or less.
Here, when performing the planarization process of the plating layer, the inventor forms a hairline after grinding the surface layer of the plating layer from the surface to a depth of about 2 μm, and the surface of the plating layer changes in color with time. Faced the problem (ie, discoloration resistance decreased).

The inventor of the present application diligently investigated the cause. As shown in FIG. 2, the surface layer of the plating layer (region from the surface to a depth of about 2 μm) has a bulk Si concentration (Si in a region deeper than 2 μm from the surface). It was discovered that Si is present at a concentration about twice as large as the concentration. FIG. 2 illustrates an Si concentration curve when the bulk Si concentration (base Si concentration) is 10%. That is, it is considered that the resistance to discoloration is lowered by removing the Si-enriched layer (region having a thickness of 2 μm on the surface of the plating layer) as described above during the flattening process of the plating layer.
Therefore, the inventor of the present application formed a hairline in a state where the Si concentrated layer was left based on the above investigation results. If the maximum Si content in the Si concentrated layer was 12 to 24% by mass, It has been found that the resistance to discoloration is improved (for details, refer to Examples described later).
Therefore, it is preferable that the maximum content of Si in the 2 μm thick region (Si enriched layer) of the surface layer of the plating layer is 12 to 24% by mass. In order to leave the Si-enriched layer, it is preferable to employ a preliminary skin pass (light rolling performed with a roll having low roughness) as the planarization treatment of the plating layer.

  In order to form an excellent hairline on the surface of the Al-based alloy-plated steel material (that is, the surface of the plating layer), the surface roughness Ra in the direction perpendicular to the hairline (C direction) is 0.3 to 2.0 μm. The thickness is preferably 0.3 to 1.0 μm. If the surface roughness Ra in the C direction is less than the lower limit, the hairline becomes inconspicuous and the hairline finish is wasted. On the other hand, if the surface roughness Ra exceeds the upper limit, the hairline becomes too rough, and it does not become a beautiful hairline, and the design as a hairline is impaired and the commercial value is lost. The surface roughness Ra was measured by adopting a reference length of 0.8 mm according to the measuring method defined in JIS B060 (1997).

When the surface roughness Ra in the direction perpendicular to the hairline is 0.3 to 2.0 μm, the number of peaks at the reference level 300 μin (PPI: Peaks Per Inch) is 0, the PPI at the reference level 200 μin is less than 10, and the reference level is 30 μin. The PPI is preferably 50 or more. Based on SAEJ911, the reference level was counted as one peak when the negative reference level -H was exceeded and then the positive reference level + H was exceeded.

  In the case where the reference level is 200 μin or more, if the PPI exceeds the above numerical value, a portion where the steel material base is exposed or the plating layer becomes locally thin may occur, which may affect the corrosion resistance. On the other hand, when the PPI at the reference level of 30 μin is less than 50, the hairline becomes inconspicuous.

  When the surface roughness Ra in the direction perpendicular to the hairline is 0.3 to 1.0 μm, the PPI of the reference level 300 μin is 0, the PPI of the reference level 200 μin is 0, the PPI of the reference level 100 μin is less than 10, and the reference level is 30 μin. The PPI is preferably 50 or more. This is the same reason as when the surface roughness Ra is 0.3 to 2.0 μm. That is, in the case where the reference level is 100 μin or more, if the PPI exceeds the above numerical value, a steel material base is exposed or a portion where the plating layer is locally thinned may occur, which may affect the corrosion resistance. On the other hand, when the PPI at the reference level of 30 μin is less than 50, the hairline becomes inconspicuous. The hairline defined by the surface roughness Ra and PPI has a hairline appearance that gives a soft impression. In addition, since the amount of grinding of the hairline is reduced, it is advantageous in continuous operability such as alleviation of clogging of the polishing belt. Here, the peak number PPI was measured with a measurement length of 1 inch in accordance with the provisions of SAEJ 911-1986.

  In order to form a hairline that satisfies the requirements for the surface roughness Ra and the peak number PPI, it is preferable to perform a hairline finish using a belt sander (polishing belt) of about # 150 to # 320. Or you may employ | adopt the method of transcribe | transferring from the roll in which the hairline pattern was formed in the surface. From the viewpoint of design properties, it is sufficient to process the hairline only on the side that will be the surface of the processed product, but it is also possible to process the hairline on both sides.

After performing the hairline processing, it is preferable to perform a primary rust prevention treatment by subjecting the plating layer to a chromate treatment or a chromate-free treatment. This is the primary rust-prevention layer in which a rust-proof coating layer is formed by chromate treatment or chromate-free treatment after the hairline finish is applied to the plating layer for the purpose of preventing discoloration and improving the adhesion of the transparent film layer described later. Process. In the case of chromate treatment, for example, chromate treatment with a chromate treatment solution containing chromic acid and a reaction accelerator as main components can be applied, and the chromate adhesion amount is set to 1 to 200 mg / m ² . When the chromate adhesion amount is less than 1 mg / m ² , a sufficient rust prevention effect cannot be obtained. Moreover, when the amount of chromate adhesion exceeds 200 mg / m ² , not only the hairline finish becomes inconspicuous, but also the rust prevention effect is saturated and the cost is increased economically. Similarly to the chromate treatment, the primary rust-proofing treatment can be performed by chromate-free treatment (non-chromate treatment).

Treatment liquids that can be used for chromate-free treatment (non-chromate treatment) include treatment liquids that do not contain environmentally harmful hexavalent chromium, such as Zr and Ti salts, or silane coupling agents. Examples of the treatment liquid include. In these chromate-free treatments, a chromate-free treatment layer (chemical conversion treatment layer) containing no chromium and containing mainly Ti, Zr, P, Ce, Si, Al, Li, or the like is formed. Deposition amount of the chromate-free treatment layer is preferably in a 1 to 1000 mg / m ^2. When the adhesion amount of the chromate-free treatment layer is less than 1 mg / m ² , a sufficient rust prevention effect cannot be obtained. Moreover, when the adhesion amount of a chromate-free process layer exceeds 1000 mg / m < ² >, not only hairline finish will become inconspicuous, but a rust prevention effect will be saturated and it will become expensive economically.

Further, when a hairline finish is applied to an Al-based alloy plated steel material and left in the air, the plating surface is oxidized and discolored. When the color changes, the hairline finish becomes inconspicuous and the appearance of the hairline is impaired. Furthermore, the Al-based alloy plating layer is easily wrinkled when it collides with a hard object. For this reason, if a transparent resin film layer is formed in the thickness of 0.5-100 micrometers on the plating surface which gave the hairline finish, discoloration resistance and an abrasion resistance can be improved. The transparent resin coating layer can be formed by a known coating method such as using an organic clear paint. Specific examples of such organic clear paints include acrylic baking clear paints, urethane clear paints, epoxy clear paints, polyester clear paints, polyethersulfone clear paints, and melamine alkyd clear paints. Can be mentioned. Moreover, you may use the mixture of these coating materials. Specific examples of the coating method of the organic clear paint include a roll coater method, a curtain coater method, a spray gun method, and an electrostatic method. Among these, the roll coater method and the curtain coater method are preferable.
In addition, such a transparent resin film layer may be directly formed on the surface of the plating layer, or may be formed on the surface of a chemical conversion treatment layer (for example, a chromate-free treatment layer) formed on the surface of the plating layer. May be.

  Hereinafter, the present invention will be described in detail based on examples.

  A low carbon steel plate having a thickness of 0.6 mm was used as a plating original plate. A plating layer was formed on the plating original plate by subjecting the plating original plate to heat treatment, annealing treatment and plating treatment in a non-oxidizing furnace type continuous melt plating line. The annealing atmosphere enclosed 10% hydrogen and the remaining 90% nitrogen gas atmosphere, and the dew point was −30 ° C. The annealing temperature is 730 ° C., and the annealing time is 3 minutes. The plating bath composition was adjusted by adding Si to Al. The plating bath temperature was set to the liquidus temperature of each plating composition + 20 ° C., and after being immersed in the plating bath for 2 seconds, the plating adhesion amount was controlled by a nitrogen gas wiping method.

  After forming the plating layer, smoothing treatment using pre-rolling is performed, and after the surface roughness Ra is set to 0.5 μm, a belt sander having a different polishing paper count is used, and a sheeting speed is 0.25 m / sec. Hairline finishing was performed under the condition of time 3 seconds. In addition, regarding the abrasive paper counts # 120 and # 150, the effect of changing the pressing pressure on the PPI at the reference levels of 300 μm and 200 μm was investigated. The surface roughness (Ra) and the number of peaks (PPI) in the direction perpendicular to the hairline were examined using a roughness meter. When the PPI did not satisfy the example of the present invention at a certain reference level, measurement was not performed at other reference levels, and “−” was shown in the table. Moreover, the damage state of a plating layer was investigated by the rusting situation 24 hours after the salt spray test of JIS Z2331, and it was set as the rejection when rusting was recognized from the hairline recessed part. The results are shown in Table 1.

As shown in Table 1, no. 4-7 satisfy | filled the conditions of surface roughness (Ra) and the number of peaks (PPI), and became the highly corrosion-resistant plated steel materials which have a beautiful hairline appearance. No. Nos. 4 and 5 are suitable when a sharp sharpness is desired. Nos. 6 and 7 are suitable when a slightly soft appearance is desired. No. As for Nos. 4 and 5, clogging of the belt sander gradually occurred when the plate-passing distance exceeded 500 m, and a little attention was required during continuous operation.

  On the other hand, No. 120 which performed hairline processing with the # 120 belt sander. No. 1 and No. 2 which performed hairline processing with a high pressing pressure using a # 150 belt sander. No. 3 had deep hairline wrinkles, and rusting was observed from the hairline recesses. No. No. 8 was subjected to hairline finishing, but the belt sander was too coarse with # 500 and did not satisfy the requirements of the hairline defined in the present invention, and the hairline could not be clearly observed in appearance. From the above test results, only the plated steel sheet satisfying the requirements defined in the present invention was a plated steel sheet having a beautiful hairline appearance.

Next, a plated steel sheet with various changes in the composition of the plating layer is prepared, and after plating, a smoothing process using pre-rolling is performed, and the surface roughness Ra is set to 0.5 μm. Using a belt sander, hairline finishing was performed under the conditions of a sheeting speed of 0.25 m / second, a polishing time of 3 seconds, and a pressing pressure of 0.2 MPa. At that time, the appearance of hairline and the state of adhesion of dregs were investigated. The results are shown in Table 2. No. Nos. 8 to 15 had a plating composition defined in the present invention, and were good results in both hairline appearance and belt sander dullness, that is, corrosion resistance. On the other hand, no. 7 and 16 are platings other than the composition specified by the present invention, and the surface roughness value satisfies the value specified by the present invention, but the appearance of the hairline cannot be clearly observed, and the generation of flaws and corrosion resistance is poor. Met. The reason why the appearance of the hairline could not be clearly observed is considered to be due to the occurrence of debris or the belt sander.

Next, a plated steel sheet with various coating layer adhesion amounts is prepared, and after plating, a smoothing process using pre-rolling is performed, and the surface roughness Ra is set to 0.5 μm. Using a belt sander, hairline finishing was performed under the conditions of a plate passing speed of 0.25 m / sec, a polishing time of 3 sec, and a pressing pressure of 0.2 MPa. The results are shown in Table 3. No. Nos. 18 to 24 had a plating adhesion amount defined in the present invention, and were good results in both hairline appearance and belt sander debris, that is, corrosion resistance. On the other hand, no. 17 is a plating with less than the adhesion amount specified by the present invention, and the surface roughness value satisfies the value specified by the present invention, but the corrosion resistance was poor. No. No. 25 had a large amount of adhesion and a poor appearance.

Furthermore, chromate treatment, chromate-free treatment, clear coating treatment, and corrosion resistance evaluation were performed using a plated steel sheet having a composition of Al-10 mass% Si. The results are shown in Tables 4 and 5. In the chromate treatment, a chromic acid 100 g / l solution was applied and then dried in a hot air oven at 60 ° C. for 30 seconds. In the chromate-free treatment, a chemical agent consisting of ammonium zirconium carbonate, cobalt nitrate, silica, and ammonium phosphate was applied and then dried in a hot air oven at 60 ° C. for 30 seconds. Further, a melamine alkyd clear paint (solvent system) and a urethane clear paint (water dispersion system) were applied and heated to plate temperatures of 220 ° C. (melamine alkyd system) and 150 ° C. (urethane system).

  The evaluation of the corrosion resistance and discoloration resistance of the flat portion was judged by the amount of white rust generated after 240 hours of the salt spray test of JIS Z2331, A: discoloration, white rust generation 1% or less, B: 10% or more. The cross-cut portion was evaluated based on the blister width after 240 times of the salt spray test, and judged by AA: less than 2 mm, A: less than 5 mm, and B: 5 mm or more.

The evaluation of the scratch resistance is based on the pencil hardness of JIS K5600. The test is repeated twice, and if the two judgments are different, the test is repeated and the hardness scale is lowered to a hardness that does not cause scratches. The above was judged acceptable. The order of pencil hardness is (soft) 6B to HB to 6H (hard).

  The level satisfying the chemical conversion treatment and coating requirements defined in the present invention was good in corrosion resistance, discoloration resistance, and scratch resistance in both the flat portion and the crosscut portion.

Next, a plated steel sheet in which the Si concentration in the bath was changed in the range of 5 to 12% was created, and after plating, smoothing treatment using pre-rolling was performed. At that time, the rolling load was changed to change the surface roughness Ra in the range of 0.3 to 1 μm. Then, using a belt sander of polishing paper count # 180, the plate speed was changed to 0.25 m / sec, and the polishing time was changed in the range of 3 to 30 seconds to find a condition for obtaining a beautiful hairline appearance. . When the surface roughness after the smoothing treatment was large, a beautiful hairline could not be obtained unless polished for a long time. Moreover, the plating thickness ground at the time of hairline processing was calculated | required by measuring the weight per unit area before and behind hairline processing. The results are shown in Table 6. No. 64 to 66, 68, 69, 71, 72 has a surface roughness after smoothing treatment of 0.5 μm or less, and the plating layer thickness ground to obtain a beautiful hairline is as small as 0.5 μm, It is a plated steel sheet having a Si-concentrated layer with a maximum Si content (12 to 24% by mass) as defined in the present invention, and no discoloration occurred over time (discoloration resistance pass). On the other hand, no. 61-63, 67, and 70 are plated steel sheets having a Si-enriched layer having a maximum Si content (less than 12% by mass) that is not specified in the present invention, and discoloration occurred with time (discoloration resistance). failure).
In addition, the pass / fail judgment of discoloration resistance was evaluated by color difference measurement ΔE. The color difference measurement ΔE is a value defined by the following equation (1).
ΔE = {(ΔL) ² + (Δa) ² + (Δb) ² } ^1/2 (1)
Here, ΔL, Δa, and Δb are the difference between the CIE1976 lightness L of the two object colors and the difference between the color coordinates a and b before and after the test in the Lab display system defined in JIS Z 8729. The evaluation criteria are as follows.
Pass: ΔE ≦ 2 No change in color tone or unevenness is observed visually.
Fail: ΔE> 2 Color change and unevenness can be identified visually.

From the above results, it was confirmed that the examples of the present invention had a beautiful hairline appearance and were excellent in corrosion resistance, discoloration resistance, and scratch resistance.

The Al-based alloy-plated steel material having the hairline appearance of the present invention enables low cost, high corrosion resistance, high discoloration resistance, and high designability in applications such as surface materials for electrical equipment, interior materials and exterior materials for buildings and vehicles, etc. An excellent material can be provided.

1 Contact Wheel 2 Idle Roll 3 Polishing Belt 4 Uncoiler 5 Coiler 6 Metal Band

(2) In the Al-based alloy-plated steel material having the hairline appearance described in (1) above, the hairline has a surface roughness Ra in a direction perpendicular to the hairline of 0.3 to 1.0 μm ; 0; PPI of reference level 200 μin is 0; PPI of reference level 100 μin is less than 10; PPI of reference level 30 μin is 50 or more;

Claims (5)

A hairline is formed on the surface of the plating layer composed of Si and the remaining Al and impurities, and an Al-based alloy plated steel material having a hairline appearance,
The plating layer is
The amount of adhesion per one side of the plating layer is 20 to 100 g / m ² ;
The Si content of the entire plating layer is 5 to 12% by mass;
The maximum content of Si in the region of 2 μm thickness of the surface layer of the plating layer is 12 to 24% by mass;
And
The hairline is
Surface roughness Ra in a direction perpendicular to the hairline is 0.3 to 2.0 μm;
PPI of reference level 300 μin is 0;
PPI at a reference level of 200 μin is less than 10;
50 or more PPI with a reference level of 30 μin;
An Al-based alloy-plated steel material having a hairline appearance. When the surface roughness Ra in the direction perpendicular to the hairline is 0.3 to 1.0 μm,
PPI of reference level 300 μin is 0;
PPI at reference level 200 μin is 0;
PPI at a reference level of 100 μin is less than 10;
50 or more PPI with a reference level of 30 μin;
The Al-based alloy-plated steel material having a hairline appearance according to claim 1. Wherein the surface of the plating layer, Al alloy coated steel material having a hairline appearance according to claim 1 or 2 to a chemical conversion treatment layer and having 1 to 1000 mg / m ^2. 3. The Al-based alloy-plated steel material having a hairline appearance according to claim 1, comprising a transparent film layer having a thickness of 0.5 to 100 μm on the surface of the plating layer. The Al-based alloy-plated steel material having a hairline appearance according to claim 3, wherein a transparent film layer having a thickness of 0.5 to 100 µm is formed on a surface of the chemical conversion treatment layer.

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