JP5408384B2 - Painted steel - Google Patents

Description

The present invention relates to a paint-plated steel material.
This application claims priority based on Japanese Patent Application No. 2011-182890 filed in Japan on August 24, 2011 and Japanese Patent Application No. 2011-182830 filed on August 24, 2011 in Japan. And the contents thereof are incorporated herein.

  Conventionally, molten Zn—Al-based plated steel materials have been widely used for applications such as building materials, materials for automobiles, and materials for home appliances. Among them, high aluminum (25 to 75 mass%) / zinc alloy plated steel sheet represented by 55% aluminum / zinc alloy plated steel sheet (Galbarium steel sheet (registered trademark)) has corrosion resistance as compared with normal hot dip galvanized steel sheet. Because of its superiority, demand continues to expand. In recent years, in particular, in response to demands for further corrosion resistance improvement and workability improvement for building materials, improvement of corrosion resistance and the like of molten Zn-Al-based plated steel materials by adding Mg or the like to the plating layer has been attempted (patents). References 1-4).

  However, in a high aluminum / zinc alloy-plated steel sheet containing Mg, wrinkles are likely to occur on the surface of the plating layer. Furthermore, since this wrinkle causes a steep bulge on the surface of the plating layer, when a chemical conversion treatment is applied to the plating layer to form a chemical conversion treatment layer, or a coating layer is applied to form a coating layer, The thickness of the chemical conversion treatment layer or the coating layer tends to be non-uniform. For this reason, there exists a problem that the improvement of the corrosion resistance of the plated steel plate by coating etc. is not fully exhibited.

For example, Patent Document 1 contains Al in a mass% containing 3 to 13% Si, 2 to 8% Mg, and 2 to 10% Zn, with the balance being a hot-dip plated layer consisting of Al and inevitable impurities. -Si-Mg-Zn based Al-plated steel sheet is disclosed. In Patent Document 1, the hot-dip plated layer further contains 0.002 to 0.08% of Be and 0 to 0.1% of Sr, or 3 to 13% of Si, 2 to 8% of Mg, and Zn. 2-10%, Be 0.003-0.05%, Sr 0-0.1%, or Si 3-13%, Mg 2-8%, Zn 2-10%, Be 0 to 0.003%, Sr 0.07 to 1.7%, or Si 3 to 13%, Mg 2 to 8%, Zn 2 to 10%, Be 0 to 0.003 %, Sr 0.1-1.0%, or Si 3-13%, Mg 2-8%, Zn 2-10%, Be 0.003
-0.08%, Sr 0.1-1.7%, or Si 3-13%, Mg 2-8%, Zn 2-10%, Be 0.003-0.05 %, Sr is contained 0.1 to 1.0%.

  In the technique disclosed in Patent Document 1, the corrosion resistance of the hot-dip plated steel material is improved by adding Mg to the plating layer. However, wrinkles are likely to occur in the plating layer due to the addition of Mg. Patent Document 1 also describes that Mg oxidation is suppressed by adding Sr or Be to the plating layer, and as a result, wrinkles are suppressed. However, wrinkle suppression is not sufficient.

  Such wrinkles formed in the plating layer are difficult to remove sufficiently even by a temper rolling process and the like, causing deterioration of the appearance of the hot-dip plated steel material.

  In addition, conventional high aluminum (25 to 75 mass%) and zinc alloy plated steel sheets are plated layer durability (corrosion rate of the plating layer), red rust resistance (characteristics that suppress red rust generated from the steel sheet), or coating Although the red rust resistance and paint film swell resistance of the cut end surface of the plated steel sheet have been improved, the corrosion resistance of the scratched part of the painted surface and the processed part where the underlying steel material has been deformed (corrosion of the plating layer and white rust) No consideration has been given to the viewpoint of improving the performance of suppressing the deterioration of the appearance due to the occurrence of rust (the white rust resistance of the plating layer) or the performance of suppressing the coating film from swelling due to the corrosion reaction. In particular, no consideration is given to the improvement of white rust resistance in the case of receiving heating during the use and in the case of receiving irradiation of ultraviolet rays in the long-term use.

Japanese Patent Laid-Open No. 11-279735 Japanese Patent No. 3718479 International Publication No. 2008/025066 Pamphlet Japanese Unexamined Patent Publication No. 2007-284718

  The present invention has been made in view of the above reasons. The purpose is to have good corrosion resistance of the scratched part of the painted surface and the processed part where the underlying steel material is deformed. An object of the present invention is to provide a coated plated steel material that has good white rust resistance when the treated layer and the plating layer are exposed and exposed to ultraviolet rays, and has a good appearance without any appearance defect due to the plating layer. .

  The present inventors considered the problem of the appearance deterioration of the above-mentioned coating plating material surface as follows. At the time of hot dipping using a hot dipping bath containing Mg, Mg is an element that oxidizes more easily than other elements that make up the plating layer. It reacts with oxygen to produce an Mg-based oxide. Accordingly, Mg is concentrated on the surface layer of the hot dip metal, and the formation of an Mg-based oxide film (a film made of an oxide of a metal containing Mg) is promoted on the surface layer of the hot dip metal. In the process where the hot dip metal is cooled and solidified, the Mg-based oxide film is formed before the solidification inside the hot dip metal is completed, so there is a difference in fluidity between the surface layer and the inside of the hot dip metal. Occurs. For this reason, even if the inside of the hot-dipped metal flows, the Mg-based oxide film on the surface layer does not follow, and as a result, the appearance defect occurs when the generated wrinkles and sagging cannot be concealed by the coating applied to the upper layer It is thought that.

  Therefore, the present inventors have intensively studied in order to suppress the difference in fluidity in the hot dip metal during the hot dip treatment as described above, and have found a means for suppressing deterioration in appearance such as wrinkles and sagging. .

  On the other hand, in addition to the coating ground treatment of hot-dip plated material that can suppress the decrease in white rust resistance of the processed parts after coating due to the decrease in the workability of the plating layer that accompanies it, Zn in the plating metal Suppresses the occurrence of white rust that is likely to occur especially in processed parts due to sacrificial anticorrosive action of Mg and Mg. As a result of earnestly researching the coating ground treatment of hot dipped plating material that can suppress white rust that tends to occur when the treatment layer and plating layer are exposed and irradiated with ultraviolet rays, etc., and can maintain a beautiful appearance for a long time, The present invention has been completed.

That is, it is as follows when the summary of this invention is shown with preferable embodiment.
(1) The coated plated steel material according to the first aspect of the present invention includes a steel material and a coating on a surface of the steel material, and the coating is in order from the steel material in the order closer to the steel material, and the plating. A coating ground treatment layer on the surface of the layer, and an organic coating layer on the surface of the coating ground treatment layer, the plating layer contains Al, Zn, Si and Mg as constituent elements, and further contains Cr, And Al content is 25-75 mass%, Mg content is 0.1-10 mass%, Cr content is 0.02-1.0 mass% , The said plating layer is 0.2-15 volume%. The mass ratio of Mg in the Si—Mg phase to the total amount of Mg in the plating layer is 3% or more and 100% or less. The organosilicon compound includes an alkylene group and a siloxane. And a crosslinkable functional group represented by —SiR ¹ R ² R ³ , ^{two of} R ¹ , R ² , and R ³ are each an alkoxy group or a hydroxy group, The remaining one of R ¹ , R ² , and R ³ is an alkoxy group, a hydroxy group, or a methyl group, and the organosilicon compound is 2 to 100 parts by mass of the organic resin. 1500 parts by mass, and the thickness of the organic coating layer is 0.2 to 100 μm.

  (2) The coated steel material described in (1) above has an Mg content in any region having a diameter of 4 mm and a depth of 50 nm in the outermost layer 50 nm deep from the surface of the plating layer. It may be 0% by mass or more and less than 60% by mass.

( 3 ) In the coated plated steel material according to the above (1) or (2) , the ratio of the Si—Mg phase on the surface of the plating layer may be an area ratio of 0% or more and 30% or less.

( 4 ) In the coated plated steel material according to any one of (1) to ( 3 ), the coating base treatment layer may contain one or more selected from a zirconium compound and a titanium compound.

( 5 ) In the coated plated steel material according to ( 4 ), 50 to 3333 parts by mass of one or more selected from the zirconium compound and the titanium compound are used in 100 parts by mass of the organic resin in the coating base treatment layer. It may be.

( 6 ) In the coated plated steel material according to ( 4 ), 1 to 50 parts by mass of at least one selected from the zirconium compound and the titanium compound is used with respect to 100 parts by mass of the organic resin in the coating base treatment layer. It may be.

( 7 ) In the coated plated steel material according to any one of (1) to ( 6 ), the coating base treatment layer further contains 0.5 to 100 parts by mass of silica with respect to 100 parts by mass of the organic resin. You may contain.

( 8 ) The coated plated steel material according to any one of (1) to ( 7 ), wherein the coating base treatment layer further includes 0.5 to 40 parts by mass of a phosphoric acid compound with respect to 100 parts by mass of the organic resin. It may contain.

( 9 ) In the coated plated steel material according to any one of (1) to ( 8 ), the coating base treatment layer is further tannin, tannic acid, or tannic acid with respect to 100 parts by mass of the organic resin. You may contain 1-50 mass parts of salt.

( 10 ) In the coated plated steel material according to any one of (1) to ( 9 ) above, the coating base treatment layer further has an etching fluoride of 0.5 to 10 with respect to 100 parts by mass of the organic resin. You may contain a mass part.

( 11 ) The coated plated steel material according to any one of (1) to ( 10 ) may be composed of two layers, a lower layer in which the organic coating layer contains a rust preventive pigment and a colored upper layer.

( 12 ) In the coated plated steel material according to any one of the above (1) to ( 11 ), the coating base treatment layer may have an adhesion amount of 10 to 2000 mg / m ² .

According to the aspects described in the above (1) to ( 12 ), the corrosion resistance of the scratched portion of the painted surface and the processed portion in which the underlying steel material is deformed is good, and when subjected to heating, and ultraviolet light for long-term use. Thus, a coated galvanized steel material having good white rust resistance in the case of receiving irradiation of the surface and having a good appearance with suppressed generation of wrinkles and sagging on the surface is provided.

It is the schematic which shows an example of the hot dipping processing apparatus in embodiment of this invention. It is the one part schematic which shows the other example of the said hot dipping processing apparatus. It is the schematic which shows the example of the heating apparatus used for the overaging process in embodiment of this invention. It is the schematic which shows the example of the heat retention container used for the overaging process in embodiment of this invention. It is the image obtained by image | photographing the cut surface of the hot dipped steel plate obtained by the level M5 of the Example with an electron microscope. It is a graph which shows the elemental-analysis result of the Si-Mg phase in the level M5 of an Example. It is a graph which shows the result of the depth direction analysis of the plating layer by the glow discharge emission-spectral-analysis apparatus about the level M5 of an Example. It is a graph which shows the result of the depth direction analysis of the plating layer by the glow discharge emission-spectral-analysis apparatus about the level M50 of an Example. It is the image obtained by image | photographing the surface of the plating layer in the hot dipped steel plate obtained by the level M5 of the Example with an electron microscope. The photograph which image | photographed the external appearance of the plating layer about the level M5 of an Example is shown. The photograph which image | photographed the external appearance of the plating layer about the level M10 of a reference example is shown. The optical microscope photograph which image | photographed the external appearance of the plating layer about the level M62 of an Example is shown. The optical microscope photograph which image | photographed the external appearance of the plating layer about the level M5 of an Example is shown. The photograph which image | photographed the external appearance of the plating layer about the level M50 of an Example is shown. It is a graph which shows the overaging treatment evaluation result about the hot dipped steel plate of the level M5 of an Example. It is an example of the schematic diagram which shows the layer structure of the coating plating steel materials in embodiment of this invention. It is an example of the schematic diagram which shows the layer structure of the coating plating steel materials in embodiment of this invention. It is an example of the schematic diagram which shows the layer structure of the coating plating steel materials in embodiment of this invention. It is an example of the schematic diagram which shows the layer structure of the coating plating steel materials in embodiment of this invention. It is an example of the schematic diagram which shows the layer structure of the coating plating steel materials in embodiment of this invention. It is an example of the schematic diagram which shows the layer structure of the coating plating steel materials in embodiment of this invention. It is an example of the schematic diagram which shows the layer structure of the coating plating steel materials in embodiment of this invention. It is an example of the schematic diagram which shows the layer structure of the coating plating steel materials in embodiment of this invention.

  Hereinafter, modes for carrying out the present invention will be described.

[Painted steel]
The paint-plated steel material according to this embodiment includes a steel material 1 and a covering 29 on the surface of the steel material 1 as shown in FIGS. 11A to 11H. The covering 29 includes, in order from the steel material 1, an aluminum / zinc alloy plating layer 23 (hereinafter referred to as “plating layer 23”), a paint ground treatment layer 24 on the surface of the plating layer 23, and a paint ground treatment layer 24. And an organic coating layer 25 on the surface. That is, the plating layer 23 is plated on the surface of the steel material 1, and the coating base treatment layer 24 and the organic coating layer 25 are sequentially coated thereon. Examples of the steel material 1 include various members such as a thin steel plate, a thick steel plate, a die steel, a steel pipe, and a steel wire. That is, the shape of the steel material 1 is not particularly limited. The plating layer 23 is formed by a hot dipping process.

[Plating layer 23]
The plating layer 23 contains Al, Zn, Si, and Mg as constituent elements. The Al content in the plating layer 23 is 25 to 75% by mass. Mg content is 0.1-10 mass%. For this reason, the corrosion resistance of the surface of the plated layer 23 is improved particularly by Al, and the edge creep at the cut end face of the hot-dip plated steel material is particularly suppressed by the sacrificial anticorrosive action of Zn, and high corrosion resistance is imparted to the hot-dip plated steel material. Furthermore, excessive alloying between Al in the plating layer 23 and the steel material 1 is suppressed by Si, and the workability of the hot-dipped steel material by an alloy layer 26 (described later) interposed between the plating layer 23 and the steel material 1. It is suppressed that damages. Furthermore, the sacrificial anticorrosive action of the plating layer 23 is strengthened and the corrosion resistance of the hot-dip plated steel material is further improved by including the Mg, which is a base metal than Zn, in the plating layer 23.

  The plating layer 23 includes 0.2 to 15% by volume of a Si—Mg phase. The Si—Mg phase is a phase composed of an intermetallic compound of Si and Mg, and is present dispersed in the plating layer 23.

  The volume ratio of the Si—Mg phase in the plating layer 23 is equal to the area ratio of the Si—Mg phase in the cut surface when the plating layer 23 is cut in the thickness direction. The Si—Mg phase on the cut surface of the plating layer 23 can be clearly confirmed by observation with an electron microscope. For this reason, the volume ratio of the Si—Mg phase in the plating layer 23 can be indirectly measured by measuring the area ratio of the Si—Mg phase on the cut surface.

  As the volume ratio of the Si—Mg phase in the plating layer 23 is higher, the generation of wrinkles in the plating layer 23 is suppressed. This is because in the process in which the hot-dip plated metal is cooled during the production of hot-dip plated steel material and solidifies to form the plated layer 23, the Si-Mg phase is hot-melted before the hot-dip plated metal is completely solidified. It is considered that the Si—Mg phase precipitates in the inside and suppresses the flow of the hot dipped metal. The volume ratio of the Si—Mg phase is more preferably 0.2 to 10%, and further preferably 0.4 to 5%.

The plating layer 23 is composed of a Si—Mg phase and other phases containing Zn and Al. The phase containing Zn and Al is mainly composed of an α-Al phase (dendritic structure) and a Zn—Al—Mg eutectic phase (interdendrite structure). Phase is comprised of phase from the more Mg-Zn ₂ depending on the composition of the plating layer 23 (Mg-Zn ₂ phase), and phase from the Si (Si phase), Fe-Al metal containing Zn and Al Various phases such as a phase composed of an intermetallic compound (Fe—Al phase) can be included. The phase containing Zn and Al occupies the portion of the plating layer 23 excluding the Si—Mg phase. Therefore, the volume ratio of the phase containing Zn and Al in the plating layer 23 is more preferably in the range of 99.8 to 85% and in the range of 99.8 to 90%, and more preferably in the range of 99.6 to 95%. More preferred.

The mass ratio of Mg in the Si—Mg phase with respect to the total amount of Mg in the plating layer 23 is 3% by mass or more and 100% by mass or less. Mg not contained in the Si—Mg phase is contained in the phase containing Zn and Al. In the phase containing Zn and Al, Mg is contained in the α-Al phase, in the Zn-Al-Mg eutectic phase, in the Mg-Zn ₂ phase, in the Mg-containing oxide film formed on the plating surface, etc. . When Mg is contained in the α-Al phase, Mg is dissolved in the α-Al phase.

The mass ratio of Mg in the Si—Mg phase to the total amount of Mg in the plating layer 23 can be calculated after the Si—Mg phase is regarded as having a stoichiometric composition of Mg ₂ Si. Actually, the Si-Mg phase may contain a small amount of elements such as Al, Zn, Cr, and Fe other than Si and Mg, and the composition ratio of Si and Mg in the Si-Mg phase is also stoichiometric. Although there may be some variation from the composition, it is very difficult to strictly determine the amount of Mg in the Si—Mg phase in consideration of these. Therefore, in the present invention, when the mass ratio of Mg in the Si—Mg phase to the total amount of Mg in the plating layer 23 is determined, as described above, the stoichiometric composition of the Si—Mg phase is Mg ₂ Si. Is considered to have

The mass ratio R of Mg in the Si—Mg phase with respect to the total amount of Mg in the plating layer 23 is calculated by the following equation (1).
R = 100 × AMg / (M × CMG / 100) (1)
R is the mass ratio (mass%) of Mg in the Si—Mg phase to the total amount of Mg in the plating layer 23, and AMg is included in the Si—Mg phase in the plating layer 23 per unit area in plan view of the plating layer 23. Mg is the Mg content (g / m ² ), M is the mass (g / m ² ) of the plating layer 23 per unit area in plan view of the plating layer 23, and CMG is the total Mg content in the plating layer 23 (Mass%) is shown respectively. Here, the mass M of the plating layer 23 per unit area in plan view of the plating layer 23 refers to the mass of the plating layer 23 attached per unit area on the surface of the steel sheet, based on the surface of the steel sheet. Say.

AMg is calculated from the following equation (2).
AMg = V ₂ × ρ ₂ × α (2)
V ₂ represents the volume (m ³ / m ² ) of the Si—Mg phase in the plating layer 23 per unit area in plan view of the plating layer 23. [rho ₂ shows the density of Si-Mg phase and its value is ^{1.94 × 10 6 (g / m} 3). α represents the mass ratio of Mg in the Si—Mg phase, and its value is 0.63.

V ₂ can be calculated from the following equation (3).
_{V 2 = V 1 × R 2} /100 ... (3)
V ₁ is the total volume (m ³ / m ² ) of the plating layer 23 per unit area in plan view of the plating layer 23, R ₂ is the volume ratio (volume%) of the Si—Mg phase in the plating layer 23, Each is shown.

V ₁ can be calculated from the following equation (4).
V ₁ = M / ρ ₁ (4)
ρ ₁ indicates the density (g / m ³ ) of the entire plating layer 23. The value of ρ ₁ is calculated by weighted averaging the densities of the constituent elements of the plating layer 23 at room temperature based on the composition of the plating layer 23.

  In this embodiment, Mg in the plating layer 23 is contained in the Si—Mg phase at a high ratio as described above. For this reason, the amount of Mg present in the surface layer of the plating layer 23 is reduced, thereby suppressing the formation of the Mg-based oxide film on the surface layer of the plating layer 23. Therefore, wrinkles of the plating layer 23 caused by the Mg-based oxide film are suppressed. As the proportion of Mg in the Si—Mg phase with respect to the total amount of Mg increases, the generation of wrinkles is suppressed. This ratio is more preferably 5% by mass or more, further preferably 20% by mass or more, and particularly preferably 50% by mass or more. The upper limit of the ratio of Mg in the Si—Mg phase to the total amount of Mg is not particularly limited, and this ratio may be 100% by mass.

  In the outermost layer having a depth of 50 nm from the surface of the plating layer 23, the Mg content is 0% by mass or more and less than 60% by mass in any region having a diameter of 4 mm (measurement part diameter) and a depth of 50 nm. It is preferable. The Mg content in the outermost layer of the plating layer 23 is measured by glow discharge optical emission spectroscopy (GD-OES). That is, as a more specific measurement method, the glow discharge intensity derived from each detected element is converted by a known coefficient or a coefficient obtained from a measured value of a standard sample whose composition is known, and the mass ratio of the elements On the other hand, the glow emission time corresponding to a depth of 50 nm is obtained from a standard sample, and the mass ratio obtained by converting the glow discharge intensity ratio of Mg is 0% by mass at any time point until the emission time obtained from the standard sample. It is measured as being above 60% by mass.

  As the Mg content in the outermost layer of the plating layer 23 is smaller, wrinkles due to the Mg-based oxide film are suppressed. This Mg content is more preferably less than 40% by mass, even more preferably less than 20% by mass, in any region where the outermost layer of the plating layer 23 has a diameter of 4 mm and a depth of 50 nm, more preferably less than 20% by mass. If it is less than%, it is especially preferable.

  The area ratio of the Si—Mg phase on the surface of the plating layer 23 is preferably 30% or less. When the Si—Mg phase is present in the plating layer 23, the Si—Mg phase is likely to be formed thin and in a mesh shape on the surface of the plating layer 23. When the area ratio of the Si—Mg phase is large, the appearance of the plating layer 23 is improved. Change. When the distribution state of the plating surface of the Si—Mg phase is not uniform, uneven gloss is visually observed on the plating layer 23. This unevenness of gloss is an appearance defect called sagging. When the area ratio of the Si—Mg phase on the surface of the plating layer 23 is 30% or less, sagging is suppressed and the appearance of the plating layer 23 is improved. Furthermore, the fact that the surface of the plating layer 23 has a small amount of Si—Mg phase is also effective for maintaining the corrosion resistance of the plating layer 23 over a long period of time. When the precipitation of the Si—Mg phase on the surface of the plating layer 23 is suppressed, the amount of precipitation of the Si—Mg phase in the plating layer 23 relatively increases. Therefore, the amount of Mg in the plating layer 23 increases, and thereby the sacrificial anticorrosive action of Mg is exerted in the plating layer 23 over a long period of time, thereby maintaining the high corrosion resistance of the plating layer 23 over a long period of time. Will come to be. In order to improve the appearance of the plating layer 23 and maintain the corrosion resistance of the plating layer 23, the area ratio of the Si—Mg phase on the surface of the plating layer 23 is more preferably 20% or less, and is preferably 10% or less. More preferably, it is particularly preferably 5% or less.

  The Mg content in the plating layer 23 is in the range of 0.1 to 10% by mass as described above. If the Mg content is less than 0.1% by mass, the corrosion resistance of the plating layer 23 is not sufficiently ensured. If this content exceeds 10% by mass, not only the corrosion resistance improving action is saturated, but also dross is likely to occur in the hot dipping bath 2 during the production of hot dipped steel. The Mg content is preferably 0.5% by mass or more, more preferably 1.0% by mass or more. The Mg content is particularly preferably 5.0% by mass or less, and more preferably 3.0% by mass or less. It is particularly preferable if the Mg content is in the range of 1.0 to 3.0% by mass.

  The content of Al in the plating layer 23 is in the range of 25 to 75% by mass. If this content is 25% by mass or more, the Zn content in the plating layer 23 is not excessive, and the corrosion resistance on the surface of the plating layer 23 is sufficiently ensured. If this content is 75% by mass or less, the sacrificial anticorrosive effect by Zn is sufficiently exhibited, and the hardening of the plating layer 23 is suppressed, so that the workability of the hot-dip plated steel material is improved. Furthermore, the content of Al is 75% by mass or less from the viewpoint of further suppressing wrinkles of the plating layer 23 by preventing the fluidity of the hot-dip plated metal from becoming excessively low during the production of hot-dip plated steel. The Al content is particularly preferably 45% by mass or more. The Al content is particularly preferably 65% by mass or less. It is particularly preferable if the Al content is in the range of 45 to 65 mass%.

  The Si content in the plating layer 23 is preferably in the range of 0.5 to 10% by mass with respect to the Al content. When the content of Si with respect to Al is 0.5 mass% or more, excessive alloying between Al in the plating layer 23 and the steel material 1 is sufficiently suppressed. If this content exceeds 10% by mass, not only the action of Si is saturated but also dross is likely to occur in the hot dipping bath 2 during the production of hot dipped steel. The Si content is particularly preferably 1.0% by mass or more. The Si content is particularly preferably 5.0% by mass or less. It is particularly preferable if the Si content is in the range of 1.0 to 5.0 mass%.

  Furthermore, the mass ratio of Si: Mg in the plating layer 23 is preferably in the range of 100: 50 to 100: 300. In this case, the formation of the Si—Mg layer in the plating layer 23 is particularly promoted, and the generation of wrinkles in the plating layer 23 is further suppressed. The mass ratio of Si: Mg is preferably 100: 70 to 100: 250, and more preferably 100: 100 to 100: 200.

Plating layer 23, it further contains Cr as an element. The growth of the Si—Mg phase in the plating layer 23 is promoted by Cr , the volume ratio of the Si—Mg phase in the plating layer 23 is increased, and the amount of Mg in the Si—Mg phase with respect to the total amount of Mg in the plating layer 23 is increased. The ratio is high. Thereby, wrinkles of the plating layer 23 are further suppressed. The content of Cr in the plating layer 23 area by der of 0.02 to 1.0 wt%. When the Cr content in the plating layer 23 is more than 1.0 mass%, not only the action is saturated, but also dross is likely to occur in the hot dipping bath 2 during the production of hot dipped steel. The Cr content is particularly preferably 0.05% by mass or more. The Cr content is particularly preferably 0.5% by mass or less. The Cr content is preferably in the range of 0.07 to 0.2% by mass.

The content of Cr in the outermost layer of 50nm depth from the surface in order Kkiso 23 is preferably 100 to 500 mass ppm. In this case, the corrosion resistance of the plating layer 23 is further improved. This is presumably because, when Cr is present in the outermost layer, a passive film is formed on the plating layer 23, and therefore, anodic dissolution of the plating layer 23 is suppressed. The content of Cr is preferably 150 to 450 ppm by mass, and more preferably 200 to 400 ppm by mass.

An alloy layer 26 containing Al and Cr is preferably interposed between the plating layer 23 and the steel material 1. In the embodiment of the present invention, the alloy layer 26 is regarded as a layer different from the plating layer 23. The alloy layer 26 may contain various metal elements such as Mn, Fe, Co, Ni, Cu, Zn, and Sn in addition to Al and Cr as constituent elements. When such an alloy layer 26 exists, the growth of the Si—Mg phase in the plating layer 23 is promoted by Cr in the alloy layer 26, and the volume ratio of the Si—Mg phase in the plating layer 23 increases, and the plating is performed. The ratio of Mg in the Si—Mg phase to the total amount of Mg in the layer 23 increases. Thereby, wrinkles and sagging of the plating layer 23 are further suppressed. In particular, the ratio of the Cr content in the alloy layer 26 to the Cr content in the plating layer 23 is preferably 2 to 50. In this case, Si—Mg phase growth is promoted in the vicinity of the alloy layer 26 in the plating layer 23, so that Si on the surface of the plating layer 23 is increased.
-The area ratio of the Mg phase is lowered, so that sagging is further suppressed and the corrosion resistance of the plating layer 23 is maintained for a longer period. The ratio of the Cr content in the alloy layer 26 to the Cr content in the plating layer 23 is preferably 3 to 40, and more preferably 4 to 25. The amount of Cr in the alloy layer 26 can be derived by measuring the cross section of the plating layer 23 using an energy dispersive X-ray analyzer (EDS).

  The thickness of the alloy layer 26 is preferably in the range of 0.05 to 5 μm. If this thickness is 0.05 μm or more, the above-described action by the alloy layer 26 is effectively exhibited. If this thickness is 5 μm or less, the workability of the hot-dip plated steel material is hardly impaired by the alloy layer 26.

  When the plating layer 23 contains Cr, the corrosion resistance after processing of the plating layer 23 is also improved. The reason is considered as follows. If the plating layer 23 is subjected to severe processing, cracks may occur in the plating layer 23. At that time, water and oxygen enter the plating layer 23 through the crack, and the alloy in the plating layer 23 is directly exposed to the corrosion factor. However, the Cr existing in the surface layer of the plating layer 23 and the Cr existing in the alloy layer 26 suppress the corrosion reaction of the plating layer 23, thereby suppressing the expansion of corrosion starting from cracks. In order to particularly improve the corrosion resistance after processing of the plating layer 23, the Cr content in the outermost layer 50 nm deeper than the surface of the plating layer 23 is preferably 300 ppm by mass or more, particularly 200 to 400. A range of mass ppm is preferred. Further, in order to particularly improve the corrosion resistance after processing of the plating layer 23, the ratio of the Cr content in the alloy layer 26 to the Cr content in the plating layer 23 is preferably 20 or more. A range of 20 to 30 is preferable.

  The plating layer 23 preferably further contains Sr as a constituent element. In this case, the formation of the Si—Mg layer in the plating layer 23 is particularly promoted by Sr. Furthermore, the formation of the Mg-based oxide film on the surface layer of the plating layer 23 is suppressed by Sr. This is considered to be because the Sr oxide film is more preferentially formed than the Mg-based oxide film, thereby inhibiting the formation of the Mg-based oxide film. Thereby, generation | occurrence | production of the wrinkle in the plating layer 23 is further suppressed. The Sr content in the plating layer 23 is preferably in the range of 1 to 1000 ppm by mass. If the Sr content is less than 1 ppm by mass, the above-described effects will not be exhibited. If the Sr content exceeds 1000 ppm by mass, not only will the Sr effect be saturated, but also melted during the production of hot-dip galvanized steel. Dross is likely to occur in the plating bath 2. The Sr content is particularly preferably 5 ppm by mass or more. The Sr content is particularly preferably 500 ppm by mass or less, and more preferably 300 ppm by mass or less. The Sr content is preferably in the range of 20 to 50 ppm by mass.

  The plating layer 23 preferably further contains Fe as a constituent element. In this case, the formation of the Si—Mg layer in the plating layer 23 is particularly promoted by Fe. Furthermore, Fe also contributes to the refinement of the microstructure and spangle structure of the plating layer 23, thereby improving the appearance and workability of the plating layer 23. The Fe content in the plating layer 23 is preferably in the range of 0.1 to 0.6 mass%. When the Fe content is less than 0.1% by mass, the microstructure and spangle structure of the plating layer 23 are coarsened to deteriorate the appearance of the plating layer 23 and the workability. If the content exceeds 0.6% by mass, the spangles of the plating layer 23 become too fine or disappear, and the appearance of the spangles cannot be improved. Dross easily occurs and the appearance of the plating layer 23 is further deteriorated. The Fe content is particularly preferably 0.2% by mass or more. The Fe content is particularly preferably 0.5% by mass or less. It is particularly preferable if the Fe content is in the range of 0.2 to 0.5 mass%. The flower pattern that appears on the surface of the steel plate 1 after plating is called spangle.

  The plating layer 23 may further contain an element selected from an alkaline earth element, Sc, Y, a lanthanoid element, Ti and B as a constituent element.

  Alkaline earth elements (Be, Ca, Ba, Ra), Sc, Y, and lanthanoid elements (La, Ce, Pr, Nd, Pm, Sm, Eu, etc.) exhibit the same action as Sr. The total content of these components in the plating layer 23 is preferably 1.0% by mass or less in terms of mass ratio.

  When at least one of Ti and B is contained in the plating layer 23, the α-Al phase (dendritic structure) of the plating layer 23 is refined to make the spangle finer. For this reason, the appearance of the plating layer 23 by spangle is improved. To do. Furthermore, the generation of wrinkles in the plating layer 23 is further suppressed by at least one of Ti and B. This is because the Si-Mg phase is also refined by the action of Ti and B, and this refined Si-Mg phase is effective in the flow of the hot-dipped metal in the process in which the hot-dipped metal is solidified and the plated layer 23 is formed. It is thought that it is to suppress it. Furthermore, the refinement of the plating structure reduces the concentration of stress in the plating layer 23 during bending, thereby suppressing the occurrence of large cracks and the like, and further improving the bending workability of the plating layer 23. In order to exhibit the said effect | action, it is preferable that the sum total of content of Ti and B in the hot dipping bath 2 is the range of 0.0005-0.1 mass% by mass ratio. The total content of Ti and B is particularly preferably 0.001% by mass or more. The total content of Ti and B is particularly preferably 0.05% by mass or less. It is particularly preferable if the total content of Ti and B is in the range of 0.001 to 0.05 mass%.

  Zn occupies the rest of the constituent elements of the plating layer 23 excluding constituent elements other than Zn.

  It is preferable that the plating layer 23 does not contain an element other than the above as a constituent element. In particular, the plating layer 23 contains only Al, Zn, Si, Mg, Cr, Sr, and Fe as constituent elements, or Al, Zn, Si, Mg, Cr, Sr, and Fe, and alkaline earth. It is preferable to contain only elements selected from the elements, Sc, Y, lanthanoid elements, Ti and B as constituent elements.

  Needless to say, however, the plating layer 23 may contain inevitable impurities such as Pb, Cd, Cu, and Mn. The content of the inevitable impurities is preferably as small as possible, and the total content of the inevitable impurities is particularly preferably 1% by mass or less with respect to the plating layer 23.

[Coated ground treatment layer 24]
The coating base treatment layer 24 coated on the upper layer of the plating layer 23 is an essential component of an organic resin and an organosilicon compound having an alkylene group, a siloxane bond, and a crosslinkable functional group represented by the following general formula (X). And
-SiR ¹ R ² R ³ (X)
R ¹ , R ² and R ³ in the formula each independently represent an alkoxy group or a hydroxy group. Further, any one of R ¹ , R ² and R ³ may be substituted with a methyl group. That is, ^{two of} R ¹ , R ² , and R ³ are each an alkoxy group or a hydroxy group, and the remaining one of R ¹ , R ² , and R ³ is an alkoxy group. Or a hydroxy group or a methyl group.

  The organic resin, which is an essential component of the coating base treatment layer 24, has excellent barrier properties against corrosion factors (water, oxygen, etc.), Mg-based oxide film formed on the surface layer of the plating layer 23, Zn of the plating layer 23, It also has excellent retention of Zn and Mg initial corrosion products produced by the sacrificial anticorrosive action of Mg. In addition, in addition to improving the adhesion between the coating ground treatment layer 24 and the plating layer 23, the organic resin imparts flexibility to the coating ground treatment layer 24, and the coating ground treatment layer 24 is plated steel material. Makes it possible to follow the deformation of For this reason, the coating ground treatment layer 24 containing the organic resin prevents the organic coating layer 25 from peeling off or lowering the adhesion even at the site where the coating plated steel material is processed and deformed. Compared to non-painted steel, it has much better corrosion resistance, especially white rust resistance, and has the effect of delaying the occurrence of red rust.

  The plating layer 23 of the present invention contains 25 to 75% by mass of Al and contains 0.2 to 15% by volume of a Si—Mg phase. As described above, the higher the volume ratio of the Si—Mg phase in the plating layer 23 is, the more the generation of wrinkles in the plating layer 23 is suppressed. On the other hand, the Si—Mg phase is hard and brittle, and thus there is no Si—Mg phase. Compared to the plated layer 23, cracks are likely to occur during processing. Even if a crack occurs, the sacrificial anticorrosive action of Zn and Mg in the plating layer 23 is exhibited, so that the red rust resistance is not impaired, but the processed part is a corrosion product of Zn or Mg. White rust is likely to occur. In addition, due to the occurrence of cracks, the adhesion with the upper organic film is lowered, and the organic film in the processed part is dropped off, so that corrosion promoting substances such as water, oxygen, and salt easily come into contact with the plating layer 23. It is also a factor that white rust is likely to occur. The organic resin, which is an essential component of the painted base treatment layer 24, also has the feature of imparting flexibility and excellent adhesion to the coating base treatment layer 24 to the plating layer 23 and the upper organic film. In other words, the coating-plated steel material having the coating ground treatment layer 24 has excellent followability to deformation (elongation and compression) of the steel material that occurs during processing, so that cracks throughout the organic coating also occur in the processed part. Even if a crack occurs in the organic coating, it is difficult for the organic coating at that position to fall off the plating surface, and the appearance and corrosion resistance (particularly white rust resistance) can be maintained.

  On the other hand, the organosilicon compound, which is another essential component of the coating base treatment layer 24, is excellent in the barrier property of the corrosion factor (water, oxygen, etc.), and is also Mg-based oxidized formed on the surface layer of the plating layer 23. It also has excellent retention of the initial corrosion products of Zn and Mg produced by the sacrificial anticorrosive action of Zn and Mg in the coating and plating layer 23. For this reason, the coating ground treatment layer 24 containing an organosilicon compound has much more excellent corrosion resistance, particularly white rust resistance, and has the effect of delaying the occurrence of red rust as compared with a hot dipped steel material without it.

  The organosilicon compound further has a feature that it has an excellent balance between flexibility and hardness. That is, the paint base treatment layer 24 containing an organosilicon compound is excellent in followability to deformation (elongation and compression) of the steel material that occurs when the plated steel material is processed, and even in the processed part, The coating base treatment layer 24 is uniformly coated without being damaged such as cracks and scratches, and can retain excellent corrosion resistance and stain resistance, and has an appropriate hardness, so that the upper organic coating film Even when the layer 25 is scratched, an effect of preventing the scratch from extending to the plating layer 23 can be expected.

  The organic resin and the organosilicon compound form a denser film by cross-linking each other, and the barrier property of the corrosion factor (water, oxygen, etc.) and the Mg-based oxidation formed on the surface layer of the plating layer 23 It can be expected that the retention property of the initial corrosion product of Zn or Mg generated by the sacrificial anticorrosive action of Zn or Mg in the coating or plating layer 23 can be expected.

  Below, the structure of the coating ground treatment layer 24 is demonstrated.

<About organic resin>
The organic resin is not limited to a specific type, and examples thereof include a polyester resin, a polyurethane resin, an epoxy resin, an acrylic resin, a polyolefin resin, and modified products of these resins. As such an organic resin, one or two or more organic resins (unmodified) may be mixed and used, or in the presence of at least one organic resin, at least one other One or two or more organic resins obtained by modifying the organic resin may be used.

  It does not specifically limit as said polyester resin, For example, what was obtained by polycondensing the polyester raw material which consists of a polycarboxylic acid component and a polyol component can be used. In addition, it is also possible to use those obtained by dissolving or dispersing the polyester resin thus obtained in water.

  Examples of the polycarboxylic acid component include phthalic acid, phthalic anhydride, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, methyltetraphthalic acid, methyltetrahydrophthalic anhydride, and hymic anhydride. , Trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, isophthalic acid, terephthalic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, adipic acid, azelaic acid, sebacic acid, succinic acid, Examples thereof include succinic anhydride, lactic acid, dodecenyl succinic acid, dodecenyl succinic anhydride, cyclohexane-1,4-dicarboxylic acid, and anhydrous endo acid. As such a polycarboxylic acid component, one of the above components may be used, or a plurality of the above components may be used.

  Examples of the polyol component include ethylene glycol, diethylene glycol, 1,3-propanediol, 1,2-propanediol, triethylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1, 3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, 2-methyl-1,4-butanediol, 2-methyl-3-methyl-1,4- Butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedim Methanol, hydrogenated bisphenol-A, dimer diol, trimethylol ethane, trimethylo Trimethylolpropane, glycerin, and pentaerythritol and the like. As such a polyol component, one of the above components may be used, or a plurality of the above components may be used.

  The polyurethane resin is not particularly limited, and examples thereof include those obtained by reacting a polyol compound and a polyisocyanate compound and then further chain-extending with a chain extender. The polyol compound is not particularly limited as long as it is a compound containing two or more hydroxyl groups per molecule. For example, ethylene glycol, propylene glycol, diethylene glycol, 1,6-hexanediol, neopentyl glycol, triethylene Examples include glycols, glycerin, trimethylolethane, trimethylolpropane, polycarbonate polyols, polyester polyols, polyether polyols such as bisphenol hydroxypropyl ether, polyester amide polyols, acrylic polyols, polyurethane polyols, or mixtures thereof. The polyisocyanate compound is not particularly limited as long as it is a compound containing two or more isocyanate groups per molecule, and examples thereof include aliphatic isocyanates such as hexamethylene diisocyanate (HDI) and fats such as isophorone diisocyanate (IPDI). An aromatic diisocyanate such as cyclic diisocyanate, tolylene diisocyanate (TDI), an araliphatic diisocyanate such as diphenylmethane diisocyanate (MDI), or a mixture thereof. The chain extender is not particularly limited as long as it is a compound containing one or more active hydrogens in the molecule. For example, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetra Aliphatic polyamines such as ethylenepentamine, aromatic polyamines such as tolylenediamine, xylylenediamine, diaminodiphenylmethane, alicyclic polyamines such as diaminocyclohexylmethane, piperazine, 2,5-dimethylpiperazine, isophoronediamine, Hydrazines such as hydrazine, succinic dihydrazide, adipic dihydrazide, phthalic dihydrazide, hydroxyethyldiethylenetriamine, 2-[(2-aminoethyl) amino] ethanol, 3-amino Alkanolamines such as propanediol and the like. These compounds can be used alone or in admixture of two or more.

  The epoxy resin is not particularly limited. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, resorcin type epoxy resin, novolac type epoxy resin. An epoxy resin such as can be used. In addition, as the epoxy resin, those epoxy resins that are forcibly emulsified with a surfactant to be water-based, or these epoxy resins are reacted with an amine compound such as diethanolamine, N-methylethanolamine, an organic acid or Uses water neutralized with inorganic acids, or water-based by radical polymerization of high acid value acrylic resins in the presence of these epoxy resins and then neutralized with ammonia or amine compounds. can do.

  The acrylic resin is not particularly limited, and examples thereof include alkyl (meth) acrylates such as ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and n-butyl (meth) acrylate, and 2-hydroxyethyl (meth). What is obtained by radical polymerization of (meth) acrylic acid esters such as hydroxyalkyl (meth) acrylates such as acrylates and alkoxysilane (meth) acrylates in water together with (meth) acrylic acid using a polymerization initiator in water. Can be mentioned. The polymerization initiator is not particularly limited, and for example, persulfates such as potassium persulfate and ammonium persulfate, and azo compounds such as azobiscyanovaleric acid and azobisisobutyronitrile can be used. Here, “(meth) acrylate” means acrylate and methacrylate, and “(meth) acrylic acid” means acrylic acid and methacrylic acid.

  The polyolefin resin is not particularly limited. For example, after radical polymerization of ethylene and unsaturated carboxylic acids such as methacrylic acid, acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid and the like at high temperature and high pressure, ammonia And basic metal compounds such as KOH, NaOH and LiOH, or those neutralized with ammonia or amine compounds containing the metal compound and converted to water.

  In addition, the organic resin contains a resin containing at least one functional group selected from an ester group, a urethane group, and a urea group in the structure in order to improve corrosion resistance and scratch resistance as a coated plated steel material. Is preferable. In order to improve the corrosion resistance of the coated plated steel material, it is necessary that the coated ground treatment layer 24 uniformly coats the plated steel material as a base material without damage such as cracks even in the processed part (the workability is improved). It is important to suppress the permeability of corrosion factors. In addition, it is important that the adhesion between the coating ground treatment layer 24 and the plating surface is high. In order to realize such a coating ground treatment layer 24, it is preferable to use an organic resin containing a specific resin structure as a film-forming component. Specifically, the above-described organic resin resin structure has been described above. By introducing such a functional group having a specific cohesive energy, both the elongation and strength of the coating film can be enhanced in a high dimension, and the adhesion and corrosion resistance can also be enhanced.

  The resin containing at least one functional group selected from an ester group, a urethane group, and a urea group in the resin structure is not particularly limited. For example, a polyester resin containing an ester group, a polyurethane resin containing a urethane group And polyurethane resins containing both urethane groups and urea groups. You may use these 1 type or in mixture of 2 or more types. For example, an organic resin containing an ester group, a urethane group, and a urea group obtained by mixing a polyester resin containing an ester group and a polyurethane resin containing both a urethane group and a urea group. May be used as

<About organosilicon compounds>
The organosilicon compound has an alkylene group, a siloxane bond, and a general formula (X)
-SiR ¹ R ² R ³ (X)
(R ¹ , R ² and R ³ in the formula independently represent an alkoxy group or a hydroxy group. In addition, any one of R ¹ , R ² and R ³ may be substituted with a methyl group. That is, ^{two of} R ¹ , R ² , and R ³ are each an alkoxy group or a hydroxy group, and the remaining one of R ¹ , R ² , and R ³ is an alkoxy group An organic silicon compound containing a crosslinkable functional group represented by: a group, a hydroxy group, or a methyl group), an adhesion between the coating ground treatment layer 24 and the plating surface, and the coating ground treatment layer 24 and Increase adhesion with upper organic coating. In addition, the organic resins or the organic resin and silica particles to be described later are cross-linked to enhance the strength of the coating base treatment layer 24 and the permeation hindrance of corrosion promoting substances such as water, oxygen, and salt.

  The organosilicon compound is not particularly limited as long as it contains an alkylene group, a siloxane bond, and a crosslinkable functional group represented by the general formula (X), but the alkylene group, the siloxane bond, and the general formula ( It is preferable that it contains the crosslinkable functional group represented by X) and can stably exist in an aqueous medium containing water as a main component. Furthermore, the organosilicon compound contains at least one crosslinkable functional group selected from an amino group, an epoxy group, and a hydroxy group (separate from those that can be included in the general formula (X)). However, it is preferable for forming a dense film having a higher crosslink density and enhancing the corrosion resistance of the coated plated steel material. In addition, since these crosslinkable functional groups exhibit hydrophilicity, when the coating composition for forming the coating base treatment layer 24 is a water-based coating, at least one selected from an amino group, an epoxy group, and a hydroxy group The inclusion of a kind of crosslinkable functional group is also advantageous for enhancing the stability of the organosilicon compound in an aqueous solvent. The stability in an aqueous solvent in the present specification indicates that it is difficult for aggregates and precipitates to be generated in an aqueous solvent over time, and that thickening and gelation are less likely to occur.

  As such an organosilicon compound, a hydrolysis condensate of a silane coupling agent can be exemplified. Specific examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldimethoxy. Silane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxy Propylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (A Noethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, bis (trimethoxysilyl) Propyl) amine, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxy Examples include silane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, and bis (trimethoxysilyl) hexane. The said silane coupling agent may be used independently and may use 2 or more types together.

  The organosilicon compound is particularly preferably obtained by a reaction between a silane coupling agent containing an amino group and a silane coupling agent containing an epoxy group. A dense film with a high crosslinking density is formed by the reaction between the amino group and the epoxy group, and the reaction between the alkoxysilyl group contained in each of the silane coupling agent and the silane coupling agent or the partial hydrolysis products thereof. This makes it possible to further improve the corrosion resistance, scratch resistance, and contamination resistance of the coated hot-dip plated steel material. Examples of the silane coupling agent containing an amino group include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- ( Aminoethyl) -3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, bis (trimethoxysilylpropyl) amine can be exemplified, and a silane coupling agent containing an epoxy group Examples of (BE) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane.

  The molar ratio BA / BE when the silane coupling agent containing an amino group is BA and the silane coupling agent containing an epoxy group is BE is preferably 0.5 or more and 2.5 or less. Preferably they are 0.7 or more and 1.6 or less. When the molar ratio BA / BE is less than 0.5, the film-forming property is lowered and the corrosion resistance improving effect may be insufficient. When it is more than 2.5, the water resistance is lowered and the corrosion resistance improving effect is obtained. May become insufficient.

  The number average molecular weight of the organosilicon compound is preferably 1000 or more and 10,000 or less, more preferably 2000 or more and 10,000 or less. Although the measuring method of molecular weight here is not specifically limited, Any of the direct measurement by TOF-MS method and the conversion measurement by the chromatography method may be used. When the number average molecular weight is less than 1000, the water resistance of the formed film is lowered, and the alkali resistance and corrosion resistance may be lowered. On the other hand, when the number average molecular weight is greater than 10,000, it is difficult to stably dissolve or disperse the organic silicon compound in an aqueous medium containing water as a main component, and the storage stability of the coating composition for forming the coating base treatment layer is difficult. May decrease. The number average molecular weight of the organosilicon compound is preferably 2000 or more and 5000 or less.

[Coated ground treatment layer 24]
The coating ground treatment layer 24 coated on the upper layer of the plating layer 23 may contain one or more selected from a zirconium compound and a titanium compound as a film forming component in addition to the organic resin and the organic silicon compound.

One or more selected from the zirconium compound and the titanium compound, which are components of the coating ground treatment layer 24, are excellent in the barrier properties (corrosion resistance) of the corrosion factors (water, oxygen, etc.) and the components excellent in the barrier properties are inorganic. Excellent heat resistance and durability against energy rays such as ultraviolet rays to form bonds. Further, the adhesion with the Al oxide and Mg oxide on the surface of the plating layer 23 is also good. That is, the hot-dip galvanized steel material coated with the coating base treatment layer 24 having at least one selected from the zirconium compound and the titanium compound as a film-forming component is resistant to white rust, particularly when heated, and for long-term use. The white rust resistance in the case of receiving ultraviolet rays is good, and the adhesion to the plating layer surface oxide is high, so that the coating base treatment layer 24 and the upper organic coating layer 25 are retained for a long period of time. Therefore, white rust resistance can be maintained for a long time.

  Below, the structure of the coating ground treatment layer 24 is demonstrated.

<About zirconium compounds and titanium compounds>
Although it does not specifically limit as a zirconium compound and a titanium compound which are contained in the processing chemical | medical agent for coating ground surface treatment layer 24 formation, For example, as a zirconium compound, a zirconyl nitrate, a zirconyl acetate, a zirconyl sulfate, an ammonium zirconium carbonate, a potassium zirconium carbonate is mentioned. , Sodium zirconium carbonate, zirconium acetate, zirconium hydrofluoric acid, or a salt thereof. Among these zirconium compounds, zirconium hydrofluoric acid or a salt thereof, and a zirconium compound containing a zirconium carbonate complex ion are preferable from the viewpoint of corrosion resistance. Is not particularly restricted but includes zirconium compounds containing zirconium carbonate complex ions, for example, zirconium carbonate complex ions _{[Zr (CO 3) 2 (OH} ) 2 ] ₂ - or _{[Zr (CO 3) 3 (OH} ) ] ₃ ^- ammonium salts, potassium salts, sodium salts.

Examples of the titanium compound include titanium potassium oxalate, titanyl sulfate, titanium chloride, titanium lactate, titanium isopropoxide, isopropyl titanate, titanium ethoxide, titanium 2-ethyl-1-hexanolate, tetraisopropyl titanate, Examples thereof include tetra-n-butyl titanate, titania sol, titanium hydrofluoric acid, or a salt thereof. Of these titanium compounds, titania sol, titanium lactate, titanium hydrofluoric acid or a salt thereof are preferable from the viewpoint of corrosion resistance.

As a compounding quantity of the said zirconium compound and a titanium compound, in order to improve a flaw part corrosion resistance, 1-333 mass parts is preferable with respect to 100 mass parts of organic resins. On the other hand, if the amount of the zirconium compound and the titanium compound is large, the ratio of the inorganic component in the base treatment component becomes high, the coating base treatment layer 24 becomes brittle, and the film adhesion when processed is inferior, resulting in corrosion resistance. Therefore, when emphasizing the corrosion resistance of the processed part, 1 to 50 parts by mass can be further added to 100 parts by mass of the organic resin. When the zirconium compound and the titanium compound are less than 1 part by mass, the corrosion factor of the corrosion factor is low due to the low barrier property (corrosion resistance) of the corrosion factor. Heat resistance and durability to energy rays such as ultraviolet rays may be insufficient. If it exceeds 3333 parts by mass, the ground treatment layer becomes brittle and the film adhesion of the film bending part is lowered, so that the corrosion resistance of the bent part may be insufficient.

  The method for producing the organosilicon compound is not particularly limited. For example, a method in which a silane coupling agent is dissolved or dispersed in water and stirred at a predetermined temperature for a predetermined time to obtain an aqueous solution of a hydrolysis condensate, silane A method of obtaining an aqueous liquid by dissolving or dispersing an organic silicon compound such as a coupling agent hydrolysis condensate in water, an organic organic compound such as silane coupling agent hydrolysis condensate such as methanol, ethanol, isopropanol, etc. Examples thereof include a method of obtaining an alcoholic liquid by dissolving in a solvent. In order to dissolve or disperse the silane coupling agent and its hydrolysis condensate in an aqueous medium, an acid, an alkali, an organic solvent, a surfactant and the like may be added as appropriate, and in particular, an organic acid is added to adjust the pH. Is preferably 3 to 6 from the viewpoint of storage stability. The solid concentration of the organic silicon compound aqueous solution or alcohol-based solution is preferably 25% by mass or less. When the solid content concentration of the organosilicon compound (B) exceeds 25% by mass, the storage stability of the aqueous liquid or alcohol-based liquid may decrease.

  The content of the organosilicon compound is 2 to 1500 parts by mass with respect to 100 parts by mass of the organic resin. If it is less than 2 parts by mass, the effect of improving the corrosion resistance may not be obtained, or the storage stability of the coating composition for forming the coating base treatment layer 24 may be lowered. On the other hand, if it exceeds 1500 parts by mass, sufficient corrosion resistance may not be obtained.

<About silica particles>
It is preferable that the coating ground treatment layer 24 further contains silica particles. By containing silica particles, the corrosion resistance can be further improved.

  Here, the silica particle content is preferably 0.5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the organic resin. If the amount is less than 0.5 parts by mass, the effect of improving the corrosion resistance may not be obtained. If it exceeds 100 parts by mass, the cohesive strength of the coating ground treatment layer 24 decreases, and the adhesion of the organic coating particularly in the processed part. May decrease. The content of the silica particles is more preferably 5 to 50 parts by mass, particularly preferably 10 to 30 parts by mass with respect to 100 parts by mass of the organic resin.

  The type of silica particles is not particularly limited, and examples thereof include silica particles such as colloidal silica and fumed silica. Examples of commercially available products include Snowtex O, Snowtex N, Snowtex C, Snowtex IPA-ST (Nissan Chemical Industry Co., Ltd.), Adelite AT-20N, Adelite AT-20A (Asahi Denka Kogyo Co., Ltd.), Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.), functional spherical silica HPS series (manufactured by Toa Gosei Co., Ltd.), Nipsil series (manufactured by Tosoh Silica Co., Ltd.) and the like.

  Moreover, it is preferable to contain spherical silica particles having an average particle diameter of 5 nm or more and 20 nm or less as silica particles in order to improve the corrosion resistance. If the average particle diameter of the spherical silica particles is less than 5 nm, the coating composition for forming the coating base treatment layer 24 may cause a problem such as gelation, and the average particle diameter is more than 20 nm. The effect of improving the corrosion resistance may not be sufficiently obtained.

<About phosphoric acid compounds>
The coating base treatment layer 24 preferably further contains a phosphoric acid compound in order to improve the corrosion resistance. More preferably, the phosphate compound is a compound that releases phosphate ions. In the case where the phosphoric acid compound is contained, when the coating base treatment layer 24 is formed, when the coating composition for forming the coating base layer contacts the plating layer 23 or after the formation of the coating base treatment layer 24, When the phosphate ion derived from the phosphate compound is eluted, it reacts with the Mg-based oxide film on the surface of the plating layer 23 to form a poorly soluble Mg-phosphate film on the surface of the plating layer 23. Thereby, white rust resistance can be improved significantly. When the phosphate compound does not release phosphate ions, that is, is insoluble in the environment, the insoluble phosphate compound improves the corrosion resistance by inhibiting the movement of corrosion factors such as water and oxygen.

  The phosphoric acid compound is not particularly limited. For example, phosphoric acids such as orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, and salts thereof, aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1, Examples thereof include phosphonic acids such as 1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) and salts thereof, and organic phosphoric acids such as phytic acid and salts thereof. The salt cation species is not particularly limited, and examples thereof include Cu, Co, Fe, Mn, Sn, V, Mg, Ba, Al, Ca, Sr, Nb, Y, Ni, and Zn. These phosphoric acid compounds (D) may be used alone or in combination of two or more.

  The content of the phosphoric acid compound is preferably 0.5 to 40 parts by mass, more preferably 2 to 15 parts by mass with respect to 100 parts by mass of the organic resin in the coating base treatment layer 24. is there. If the content of the phosphoric acid compound is less than 0.5 parts by mass, the effect of improving the corrosion resistance may not be obtained, and if it is more than 40 parts by mass, the corrosion resistance and the coating film adhesion of the processed part may decrease. In some cases, the stability of the paint for forming the coating film is lowered (more specifically, problems such as gelation and precipitation of aggregates occur).

<About tannin, tannic acid, or tannate>
The coating base treatment layer 24 preferably further contains tannin, tannic acid, or tannate.

  Tannin, tannic acid, or tannate is a general term for aromatic compounds having a complex structure having a large number of phenolic hydroxyl groups widely distributed in the plant kingdom. The tannin, tannic acid or tannic acid salt used in the coating ground treatment layer 24 may be hydrolyzable tannic acid or condensed tannic acid. The tannin is not particularly limited, and examples thereof include hameli tannin, oyster tannin, chatannin, pentaploid tannin, gallic tannin, mylobalantannin, dibidi tannin, argarovira tannin, valonia tannin, catechin tannin and the like. Tannic acid or tannic acid salt is commercially available, for example, “tannic acid extract A”, “B tannic acid”, “N tannic acid”, “industrial tannic acid”, “purified tannic acid”, “Hi Tannic acid "," F tannic acid "," local tannic acid "(all manufactured by Dainippon Pharmaceutical Co., Ltd.)," tannic acid: AL "(manufactured by Fuji Chemical Industry Co., Ltd.) and the like can also be used. These tannins, tannic acid or tannic acid salts may be used alone or in combination of two or more.

  Tannin, tannic acid or tannic acid salt adheres firmly to the plating layer 23, but also adheres to a resin, particularly an aqueous resin, so that the coating base treatment layer 24 itself and the organic coating layer 25 as an upper layer adhere to the plating surface. Improve sexiness. Even when the base plated steel material is deformed, peeling of the coating base treatment layer 24 itself and the organic coating layer 25 as an upper layer is prevented by the adhesion, and as a result, the corrosion resistance of the processed part is also improved. The content of tannin, tannic acid or tannate is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the organic resin. If the amount is less than 1 part by mass, the effect of addition is small, and if it exceeds 50 parts by mass, the corrosion resistance of the processed part and the stability of the ground treatment solution may decrease. Furthermore, preferable content is 4-20 mass parts with respect to 100 mass parts of organic resins.

<Etching fluoride>
The coating ground treatment layer 24 is further improved in adhesion with the plating surface by adding an etching fluoride. As a result, the corrosion resistance of the processed part may be improved. Here, as the etchable fluoride, zinc fluoride tetrahydrate, zinc hexafluorosilicate hexahydrate or the like can be used. The content of the etchable fluoride is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the organic resin. If it is less than 0.5 parts by mass, the effect of addition is small, and if it exceeds 10 parts by mass, the effect of etching is saturated and the adhesion is not improved, which is uneconomical.

<Adhesion amount of coating ground treatment layer 24>
Although the adhesion amount of the coating ground treatment layer 24 is not particularly limited, it is preferably 10 to 2000 mg / m ² , more preferably 20 to 1000 mg / m ² , still more preferably 20 to 300 mg / m ² , and particularly preferably 40. it is a ~120mg / ^{m 2.} When the adhesion amount of the coating ground treatment layer 24 is less than 10 mg / m ² , sufficient corrosion resistance and coating film adhesion may not be obtained. On the other hand, when the coating amount of the coating ground treatment layer 24 is more than 2000 mg / m ² , it is not only economically disadvantageous, but also when the coating ground treatment layer 24 is formed from a water-based paint, A coating film defect may occur, and the appearance and performance as an industrial product of the coated plated steel material may not be obtained stably. In addition, the cohesive force of the coating ground treatment layer 24 is insufficient and becomes brittle, and adhesion and corrosion resistance may be reduced.

  The adhesion amount of the coating ground treatment layer 24 is calculated by calculating the mass difference between the plated steel materials before and after coating, by calculating the mass difference between the plated steel materials before and after the coating ground coating layer 24 is peeled off, or by the coating film. May be obtained by a method appropriately selected from existing methods such as measuring the amount of an element whose content in the film is known in advance by fluorescent X-ray analysis.

[Organic coating layer 25]
The coated plated steel material according to each embodiment of the present invention is one in which one or more organic coating layers 25 are coated on one or both surfaces of the plated steel material via the painted ground treatment layer 24. Alternatively, the coating ground treatment layer 24 and the organic coating layer 25 may be partially omitted in a portion where high corrosion resistance and organic coating adhesion are not questioned.

  Examples of the binder resin that is a main component of the coating film of the organic coating layer 25 include polyester resin, epoxy resin, urethane resin, acrylic resin, melamine resin, and fluorine resin, and are not particularly limited. When the steel material is used for an application for processing, a thermosetting resin is more preferable. Examples of thermosetting resins include polyester resins such as epoxy polyester resins, polyester resins, melamine polyester resins, and urethane polyester resins, and acrylic resins. These resins have better processability than other resins and are difficult to process. Even afterwards, cracks are unlikely to occur in the coating layer.

  The polyester-based resin as the main component of the organic coating layer 25 is not particularly limited, but is a generally known ester compound of a polybasic acid and a polyhydric alcohol, which is generally synthesized by a known esterification reaction. Can be used.

  The polybasic acid is not particularly limited, and examples thereof include phthalic acid, isophthalic acid, terephthalic acid, phthalic anhydride, trimetic anhydride, maleic acid, adipic acid, and fumaric acid. These polybasic acids may use 1 type and may use multiple types together.

  The polyhydric alcohol is not particularly limited. For example, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, neopentylene glycol, 1,4-butanediol, 1,5-pentanediol, Examples include 1,6-hexanediol, 1,4-cyclohexanedimethanol, polytetramethylene ether glycol, glycerin, trimethylolethane, trimethylolpropane, trimethylolbutane, hexanetriol, pentaerythritol, dipentaerythritol, and the like. . These polyhydric alcohols may be used alone or in combination of two or more.

  In using the polyester resin, it is preferable to add a curing agent because the hardness of the coating layer is increased and the scratch resistance is improved. Although it does not specifically limit as a hardening | curing agent, Generally one or both of a well-known amino resin and a polyisocyanate compound can be used.

  Although it does not specifically limit as said amino resin, For example, the resin obtained by reaction of urea, a benzoguanamine, a melamine, etc., and formaldehyde, and those obtained by alkylating these with alcohol can be used. Specific examples include methylated urea resins, n-butylated benzoguanamine resins, methylated melamine resins, n-butylated melamine resins, iso-butylated melamine resins, and the like.

  Resins widely used in the field of painted hot-dip galvanized steel are polyester / melamine resins having a polyester resin as a main resin and a melamine resin as a curing agent. The melamine-based resin referred to here indicates at least one of methylated melamine, n-butylated melamine, and iso-butylated melamine.

  Although it does not specifically limit as said polyisocyanate compound, For example, the isocyanate compound blocked with blocking agents, such as a phenol, a cresol, aromatic secondary amine, tertiary alcohol, lactam, oxime, is preferable. More preferred polyisocyanate compounds include HDI (hexamethylene diisocyanate) and its derivatives, TDI (tolylene diisocyanate) and its derivatives, MDI (diphenylmethane diisocyanate) and its derivatives, XDI (xylylene diisocyanate) and its derivatives, IPDI (isophorone) Diisocyanate) and derivatives thereof, TMDI (trimethylhexamethylene diisocyanate) and derivatives thereof, hydrogenated TDI and derivatives thereof, hydrogenated MDI and derivatives thereof, hydrogenated XDI and derivatives thereof, and the like.

<Coating composition of organic coating layer 25>
In the present invention, the coating composition of the organic coating layer 25 is not particularly limited, may have only a single coating film, or may have two or more coating films, Furthermore, the structure in which one layer of coating film and two or more layers of coating films are partially mixed may be used. However, as described below, in order to ensure excellent design properties and corrosion resistance, a coating layer composed of two or more coating layers is preferable.

  When the organic coating layer 25 is a multilayer of two or more layers, it is preferable that at least one layer is a layer containing a rust preventive pigment in order to improve the corrosion resistance of the coated hot-dip plated steel material. The layer containing the rust preventive pigment is more preferably arranged on the plated steel material side than the other layers in order to improve the corrosion resistance. Although it does not specifically limit as a rust preventive pigment, For example, phosphoric acid type rust preventive pigments, such as zinc phosphate, iron phosphate, aluminum phosphate, zinc phosphite, aluminum tripolyphosphate, calcium molybdate, aluminum molybdate, barium molybdate, etc. Molybdate anticorrosion pigments, vanadium anticorrosion pigments such as vanadium oxide, silicate anticorrosion pigments such as calcium silicate, silica anticorrosion pigments such as water-dispersed silica, fumed silica, and calcium ion exchange silica Commonly known chromate-free rust preventive pigments such as ferroalloy rust preventive pigments such as ferrosilicon, or generally known chromium rust preventive pigments such as strontium chromate, potassium chromate, barium chromate and calcium chromate Can be used. However, from the viewpoint of environmental protection in recent years, it is more preferable to use a chromate-free rust preventive pigment as the rust preventive pigment in the present invention. These rust preventive pigments may be used alone or in combination of two or more.

  The addition amount of the rust preventive pigment is preferably 1% by mass or more and 40% by mass or less based on the solid content of the organic coating layer 25 containing the rust preventive pigment. If the addition amount of the rust preventive pigment is less than 1% by mass, the improvement of the corrosion resistance is not sufficient, and if it exceeds 40% by mass, the processability is lowered and the coating layer may fall off during processing, and the corrosion resistance tends to be inferior. is there.

  Moreover, when the organic coating layer 25 is a multilayer of two or more layers, it is preferable that at least one layer is a colored coating layer containing a color pigment in order to improve the design of the coated plated steel material. The outermost layer may be a colored coating layer containing a color pigment, and the outermost layer may be a highly permeable coating, and the colored coating layer may be disposed below the outermost layer.

  The coloring pigment is not particularly limited, but generally known pigments such as titanium oxide, zinc oxide, iron oxide, zirconium oxide, calcium carbonate, barium sulfate, carbon black, phthalocyanine blue, naphthol red, disazo yellow, disazopyrazolone orange, etc. Can be used. It may be an inorganic pigment or an organic pigment. Further, as the coloring pigment, generally known metallic pigments such as aluminum pigments and nickel pigments may be used, and those in the form of granules or flakes may be used. These color pigments may be used alone or in combination of two or more.

  The addition amount of the color pigment is preferably 5% by mass or more and 70% by mass or less based on the solid content of the organic coating layer 25 containing the color pigment. If the addition amount of the color pigment is less than 5% by mass, the intended designability (coloring effect) may be lowered, and if it exceeds 70% by mass, the corrosion resistance and workability of the coating layer may be inferior.

  The thickness of the organic coating layer 25 is preferably 0.2 to 100 μm. If the thickness is less than 0.2 μm, the effects such as coloring by the organic coating layer 25, imparting a design, and blocking of corrosion factors for rust prevention of the plated steel sheet are insufficient, and if it exceeds 100 μm, the effect by the coating layer is saturated and not effective. Not only is it economical, it may easily cause unevenness on the surface of the coating layer, making it difficult to obtain a uniform appearance, and may cause problems such as cracking of the organic coating at the processed parts of the coated steel sheet. . The thickness of the organic coating layer 25 is preferably 3 to 40 μm, more preferably 15 to 40 μm.

  The thickness of the organic coating layer 25 can be measured by observing a cross section of the organic coating layer 25 or using an electromagnetic film thickness meter. In addition, the mass of the organic coating layer 25 adhered per unit area of the plated steel material may be calculated by dividing by the specific gravity of the organic coating layer 25 or the specific gravity after drying of the coating solution. The adhesion mass of the organic coating layer 25 is calculated by calculating the mass difference between the plated steel materials before and after coating, calculating the mass difference between the plated steel materials before and after peeling the organic coating layer 25 after coating, or fluorescently coating the coating film. What is necessary is just to obtain | require by the method selected appropriately from the existing method, such as measuring the abundance of the element whose content in a film | membrane is known beforehand by X-ray analysis. The specific gravity of the organic coating layer 25 or the specific gravity after drying of the paint is to measure the volume and mass of the isolated organic coating layer 25, to measure the volume and mass after taking an appropriate amount of paint in a container and drying, Or what is necessary is just to obtain | require by the method selected appropriately from the existing method, such as calculating from the compounding quantity of the organic coating layer 25 structural component, and the known specific gravity of each component.

[Pretreatment layer 28]
The pre-treatment layer 28 is further provided below the paint base treatment layer 24, that is, between the paint base treatment layer 24 and the metal plate, so that the paint base treatment layer 24 and the plated steel material as the base material adhere to each other. The corrosion resistance of the coated plated steel material can be further enhanced. The composition of the pretreatment layer 28 is not particularly limited, but it is preferable to use a silane coupling agent, a crosslinkable zirconium compound, a crosslinkable titanium compound, or the like. These may be used alone or in combination of two or more.

  The type of the silane coupling agent is not particularly limited. For example, vinyltrimethoxysilane sold by Shin-Etsu Chemical Co., Toray Dow Corning, Chisso, Momentive Performance Materials Japan, etc. , Vinyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylethoxysilane, N- [2- (vinylbenzylamino) ethyl] -3-aminopropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane , Γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxy Sisilane, γ-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (amino Ethyl) -γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, etc. Can be mentioned. These silane coupling agents may be used alone or in combination of two or more.

The crosslinkable zirconium compound is not particularly limited, and examples thereof include zirconyl nitrate, zirconyl acetate, zirconyl sulfate, ammonium zirconium carbonate, potassium zirconium carbonate, sodium zirconium carbonate, zirconium acetate and the like. Of these compounds, zirconium compounds containing zirconium carbonate complex ions are preferred. The zirconium compound containing zirconium carbonate complex ions is not particularly limited, zirconium carbonate complex ions _{[Zr (CO 3) 2 (OH} ) 2 ] ^2- or _{[Zr (CO 3) 3 (OH} ) ] ^3- ammonium salt, potassium salt, sodium salt and the like. These crosslinkable zirconium compounds may be used alone or in combination of two or more.

  Although it does not specifically limit as said crosslinkable titanium compound, For example, dipropoxy bis (triethanol aminato) titanium, dipropoxy bis (diethanol aminato) titanium, propoxy tris (diethanol aminato) titanium, dibutoxy bis (triethanol aminato) Titanium, Dibutoxybis (diethanolaminato) titanium, Dipropoxybis (acetylacetonato) titanium, Dibutoxybis (acetylacetonato) titanium, Dihydroxybis (lactato) titanium monoammonium salt, Dihydroxybis (lactato) titanium diammonium salt, Propane dioxy Examples include titanium bis (ethyl acetoacetate), oxotitanium bis (monoammonium oxalate), isopropyl tri (N-amidoethylaminoethyl) titanate, and the like. It is possible. These crosslinkable titanium compounds may be used alone or in combination of two or more.

[Manufacturing method of painted steel]
The coated plated steel material according to the present embodiment is manufactured by performing aluminum / zinc alloy plating on the surface of the steel material 1, and further forming the painted ground treatment layer 24 and the organic coating layer 25 on the upper layer.

[Method of manufacturing hot-dip galvanized steel]
In a preferred embodiment, a hot dipping bath 2 having a composition that matches the composition of the constituent elements of the plating layer 23 is prepared during the production of the hot dipped steel. Although the alloy layer 26 is formed between the steel material 1 and the plating layer 23 by the hot dipping process, the variation of the composition due to this is so small that it can be ignored.

  In this embodiment, for example, 25 to 75 mass% Al, 0.5 to 10 mass% Mg, 0.02 to 1.0 mass% Cr, 0.5 to 10 mass% Si with respect to Al, A hot dipping bath 2 containing 1-1000 ppm by mass of Sr, 0.1-1.0% by mass of Fe, and Zn is prepared. Zn occupies the rest of the components in the hot dipping bath 2 excluding components other than Zn. The mass ratio of Si: Mg in the hot dipping bath 2 is preferably in the range of 100: 50 to 100: 300.

  The hot dipping bath 2 may further contain a component selected from alkaline earth elements, Sc, Y, lanthanoid elements, Ti, and B. These components are contained in the hot dipping bath 2 as necessary. The total content of alkaline earth elements (Be, Ca, Ba, Ra), Sc, Y, and lanthanoid elements (La, Ce, Pr, Nd, Pm, Sm, Eu, etc.) in the hot dipping bath 2 is The mass ratio is preferably 1.0% or less. When the hot dipping bath 2 contains a component consisting of at least one of Ti and B, the total content of Ti and B in the hot dipping bath 2 is in the range of 0.0005 to 0.1% by mass ratio. It is preferable.

  It is preferable that the hot dipping bath 2 does not contain components other than those described above. In particular, the hot dipping bath 2 preferably contains only Al, Zn, Si, Mg, Cr, Sr, and Fe. It is also preferable that the hot dipping bath 2 contains only an element selected from Al, Zn, Si, Mg, Cr, Sr, and Fe, and alkaline earth elements, Sc, Y, lanthanoid elements, Ti, and B.

  For example, when preparing the hot dipping bath 2, the hot dipping bath 2 is preferably 25 to 75% Al, 0.02 to 1.0% Cr, and 0.5 to 0.5% Si relative to Al. 10%, 0.1 to 0.5% Mg, 0.1 to 0.6% Fe, 1 to 500 ppm of Sr, or further from alkaline earth element, lanthanoid element, Ti and B It is preferable that the selected component is contained and the balance is Zn.

  However, it goes without saying that the hot dipping bath 2 may contain inevitable impurities such as Pb, Cd, Cu, and Mn. The content of the inevitable impurities is preferably as small as possible. In particular, the total content of the inevitable impurities is preferably 1% by mass or less with respect to the hot dipping bath 2 in mass ratio.

  When the hot dip plating treatment 2 is performed on the steel material 1 using the hot dip plating bath 2 having such a composition, the corrosion resistance of the surface of the plating layer 23 is improved particularly by Al, and the hot dip galvanized steel material is particularly improved by the sacrificial anticorrosive action of Zn. Edge creep at the cut end face is suppressed, and high corrosion resistance is imparted to the hot-dip plated steel material.

  Furthermore, the sacrificial anticorrosive action of the plating layer 23 is further strengthened by the plating layer 23 containing Mg, which is a base metal rather than Zn, and the corrosion resistance of the hot dipped steel is further improved.

  Furthermore, wrinkles are less likely to occur in the plating layer 23 formed by the hot dipping process. Conventionally, when molten metal containing Mg (hot-plated metal) adheres to the steel material 1 by hot-dipping treatment, Mg tends to concentrate on the surface layer of this hot-plated metal, and for this reason, an Mg-based oxide film is formed. Due to this Mg-based oxide film, the plating layer 23 was likely to wrinkle. However, when the plating layer 23 is formed by using the hot dipping bath 2 having the above composition, the concentration of Mg in the surface layer of the hot dipped metal adhering to the steel material 1 is suppressed, and the hot dipped metal flows. Also, the surface of the plating layer 23 is less likely to wrinkle. Further, the fluidity inside the hot-dip plated metal is reduced, and the flow of the hot-plated metal itself is suppressed, so that the wrinkles are less likely to occur.

  It is considered that the Mg concentration and the suppression of the flow of the hot dip metal are performed by the following mechanism.

  In the process in which the hot-dip plated metal adhering to the surface of the steel material 1 is cooled and solidified, the α-Al phase first precipitates as primary crystals and grows in a dendrite shape. As the solidification of the Al-rich α-Al phase progresses in this way, the Mg and Si concentrations in the remaining hot-dipped metal (that is, in the hot-dipped metal that has not yet solidified) gradually increase. Next, when the steel material 1 is cooled and the temperature thereof is further lowered, a Si-containing phase (Si-Mg phase) containing Si is solidified and precipitated from the remaining hot-dipped metal. This Si—Mg phase is a phase composed of an alloy of Mg and Si as described above. The precipitation and growth of this Si—Mg phase is promoted by Cr, Fe and Sr. When Mg in the hot-dipped metal is taken into this Si-Mg phase, the movement of Mg to the surface layer of the hot-dipped metal is inhibited, and the concentration of Mg on the surface layer of the hot-dipped metal is suppressed.

  Furthermore, Sr in the hot dipped metal also contributes to suppression of Mg concentration. This is because, in hot-dip metal, Sr is an element that is easily oxidized like Mg, so Sr forms an oxide film on the plating surface competitively with Mg, and as a result, formation of Mg-based oxide film is suppressed. This is considered to be because of this.

  Furthermore, as described above, the Si—Mg phase solidifies and grows in the remaining hot dip metal other than the α-Al phase which is the primary crystal, so that the hot dip metal is in a solid-liquid mixed phase. As a result, the generation of wrinkles on the surface of the plating layer is suppressed.

  Fe is important in controlling the microstructure and spangle of the plating layer 23. The reason why Fe influences the structure of the plating layer 23 is not necessarily clear at the present time, but is because Fe is alloyed with Si in the hot-dipped metal, and this alloy becomes a solidification nucleus when the hot-dipped metal is solidified. it is conceivable that.

  Furthermore, since Sr is a base element like Mg, the sacrificial anticorrosive action of the plating layer 23 is further strengthened by Sr, and the corrosion resistance of the hot-dip plated steel material is further improved. Sr also exerts an action of suppressing the acicular formation of the Si phase and the Si—Mg phase. For this reason, the Si phase and the Si—Mg phase are spheroidized, and the occurrence of cracks in the plating layer 23 is suppressed.

  During the hot dipping process, an alloy layer 26 containing a part of Al in the hot dipped metal is also formed between the plating layer 23 and the steel material 1. For example, when pre-plating described later is not performed on the steel material 1, an Fe—Al based alloy layer 26 mainly composed of Al in the hot dipping bath 2 and Fe in the steel material 1 is formed. When pre-plating described later is applied to the steel material 1, the alloy layer 26 contains Al in the hot dipping bath 2 and some or all of the constituent elements of the pre-plating, or further contains Fe in the steel material 1. Is formed.

  When the hot dipping bath 2 contains Cr, the alloy layer 26 further contains Cr as a constituent element together with Al. In addition to Al and Cr, the alloy layer 26 includes Si, Mn, Fe, Co, Ni, Cu, Zn, as constituent elements, depending on the composition of the hot dipping bath 2, the presence or absence of pre-plating, the composition of the steel material 1, and the like. Various metal elements such as Sn can be contained.

  In the alloy layer 26, a part of Cr in the hot dip metal is contained at a higher concentration than in the plating layer 23. When such an alloy layer 26 is formed, the growth of the Si—Mg phase in the plating layer 23 is promoted by Cr in the alloy layer 26, and the volume ratio of the Si—Mg phase in the plating layer 23 increases. The ratio of Mg in the Si—Mg phase to the total amount of Mg in the plating layer 23 is increased. Thereby, wrinkles of the plating layer 23 are further suppressed. Further, the formation of the alloy layer 26 further improves the corrosion resistance of the hot-dip plated steel material. That is, the growth of the Si—Mg phase is promoted in the vicinity of the alloy layer 26 in the plating layer 23, thereby reducing the area ratio of the Si—Mg phase on the surface of the plating layer 23. Is suppressed, and the corrosion resistance of the plating layer 23 is maintained for a longer period of time. In particular, the ratio of the Cr content in the alloy layer 26 to the Cr content in the plating layer 23 is preferably 2 to 50. The ratio of the Cr content in the alloy layer 26 to the Cr content in the plating layer 23 is preferably 3 to 40, and more preferably 4 to 25. The amount of Cr in the alloy layer 26 can be derived by measuring the cross section of the plating layer 23 using an energy dispersive X-ray analyzer (EDS).

  If the thickness of the alloy layer 26 is excessive, the workability of the hot dip plated steel material is lowered, but excessive growth of the alloy layer 26 is suppressed by the action of Si in the hot dip plating bath 2. Good workability is ensured. The thickness of the alloy layer 26 is preferably in the range of 0.05 to 5 μm. When the thickness of the alloy layer 26 is within the above range, the corrosion resistance of the hot-dip plated steel material is sufficiently improved and the workability is also sufficiently improved.

  Further, in the plating layer 23, the concentration of Cr is maintained within a certain range near the surface, and accordingly, the corrosion resistance of the plating layer 23 is further improved. The reason for this is not clear, but it is presumed that a composite oxide film is formed in the vicinity of the surface of the plating layer 23 by combining Cr with oxygen. In order to improve the corrosion resistance of the plating layer 23, the Cr content in the outermost layer having a depth of 50 nm in the plating layer is preferably 100 to 500 ppm by mass.

  When the hot dipping bath 2 contains Cr, the corrosion resistance after the bending deformation of the plating layer 23 is also improved. The reason is considered as follows. When subjected to severe bending deformation, cracks may occur in the plating layer 23 and the coating film on the plating layer 23. At that time, water and oxygen enter the plating layer 23 through the crack, and the alloy in the plating layer 23 is directly exposed to the corrosion factor. However, the Cr existing in the surface layer of the plating layer 23 and the Cr existing in the alloy layer 26 suppress the corrosion reaction of the plating layer 23, thereby suppressing the expansion of corrosion starting from cracks.

  The hot-dip plated metal treated in the preferred embodiment is a multi-component molten metal containing elements of seven or more components, and its solidification process is extremely complicated and difficult to predict theoretically. Have obtained the above-mentioned important findings through observations in experiments and the like.

  By adjusting the composition of the hot dipping bath 2 as described above, the suppression of wrinkles and sagging in the plated layer 23 and the securing of the corrosion resistance and workability of the hot dipped steel can be achieved as described above.

  When the Al content in the hot dipping bath 2 is less than 25%, the Zn content in the plating layer 23 becomes excessive, and the corrosion resistance on the surface of the plating layer 23 becomes insufficient, and this content is more than 75%. If it increases, the sacrificial anticorrosive effect by Zn will fall, and the plating layer 23 will become hard and the bending workability of hot dipped steel will fall. Furthermore, if this content exceeds 75%, the fluidity of the hot-dip plated metal increases, and wrinkles may be generated in the plated layer 23. The Al content is particularly preferably 45% or more. The Al content is particularly preferably 65% or less. In particular, the Al content is preferably in the range of 45 to 65%.

  If the Cr content in the hot dip plating bath 2 is less than 0.02%, the corrosion resistance of the plating layer 23 will not be sufficiently secured, and the wrinkles and sagging of the plating layer 23 will not be sufficiently suppressed. If it exceeds 1.0%, not only the effect of improving the corrosion resistance is saturated but also dross is likely to occur in the hot dipping bath 2. The Cr content is particularly preferably 0.05% or more. The Cr content is particularly preferably 0.5% or less. The Cr content is preferably in the range of 0.07 to 0.2%.

  When the content of Si with respect to Al in the hot dipping bath 2 is less than 0.5%, the above-described action is not exhibited. When this content exceeds 10%, not only the action of Si is saturated but also the hot dipping bath 2 Dross is likely to occur inside. The Si content is particularly preferably 1.0% or more. The Si content is particularly preferably 5.0% or less. Furthermore, the Si content is preferably in the range of 1.0 to 5.0%.

  If the Mg content in the hot dipping bath 2 is less than 0.1%, the corrosion resistance of the plating layer 23 is not sufficiently secured, and if this content exceeds 10%, the corrosion resistance improving action is only saturated. And dross is likely to occur in the hot dipping bath 2. The Mg content is preferably 0.5% or more, and more preferably 1.0% or more. Further, the Mg content is particularly preferably 5.0% or less, and more preferably 3.0% or less. In particular, the Mg content is preferably in the range of 1.0 to 3.0%.

  If the Fe content in the hot dipping bath 2 is less than 0.1%, the microstructure and spangle structure of the plating layer 23 are coarsened, and the appearance of the plating layer 23 may be deteriorated and workability may be deteriorated. If the content exceeds 0.6%, the spangles of the plating layer 23 become too fine or disappear, and the appearance is not improved by spangles, and dross is likely to occur in the hot dipping bath 2. turn into. The Fe content is particularly preferably 0.2% or more. The Fe content is particularly preferably 0.5% or less. In particular, the Fe content is preferably in the range of 0.2 to 0.5%.

  When the content of Sr in the hot dip plating bath 2 is less than 1 ppm, the above-mentioned action is not exhibited. When the content exceeds 500 ppm, not only does the action of Sr saturate, but also dross in the hot dip bath 2 is obtained. Is likely to occur. The Sr content is particularly preferably 5 ppm or more. The Sr content is particularly preferably 300 ppm or less. The Sr content is preferably in the range of 20 to 50 ppm.

  When the hot dipping bath 2 contains a component selected from alkaline earth elements and lanthanoid elements, alkaline earth elements (Be, Ca, Ba, Ra), Sc, Y, and lanthanoid elements (La, Ce, Pr, Nd, Pm, Sm, Eu, etc.) exhibit the same action as Sr. As described above, the total content of these components in the hot dipping bath 2 is preferably 1.0% or less.

  In particular, when the hot dipping bath 2 contains Ca, generation of dross in the hot dipping bath 2 is remarkably suppressed. In the case where the hot dipping bath 2 contains Mg, even if the Mg content is 10% by mass or less, a certain amount of dross is unavoidable, and in order to ensure a good appearance of the hot dipped steel. Although it is necessary to remove dross from the hot dipping bath 2, when the hot dipping bath 2 further contains Ca, dross generation due to Mg is remarkably suppressed. This further suppresses deterioration of the appearance of the hot dipped steel material due to dross, and reduces the effort required to remove the dross from the hot dipping bath 2. The Ca content in the hot dipping bath 2 is preferably in the range of 100 to 5000 ppm by mass. Generation | occurrence | production of the dross in the hot dipping bath 2 is suppressed effectively because this content is 100 mass ppm or more. If the Ca content is excessive, dross due to this Ca may occur, but if the Ca content is 5000 mass ppm or less, dross due to Ca is suppressed. This content is preferably in the range of 200 to 1000 ppm by mass.

  When at least one of Ti and B is contained in the hot dipping bath 2, the spangle of the plating layer 23 is refined by refining the α-Al phase (dendritic structure) of the plating layer 23. The appearance of the plating layer 23 is improved. Furthermore, the generation of wrinkles in the plating layer 23 is further suppressed. This is because the Si-Mg phase is also refined by the action of Ti and B, and this refined Si-Mg phase is effective in the flow of the hot-dipped metal in the process in which the hot-dipped metal is solidified and the plated layer 23 is formed. It is thought that it is to suppress it. Furthermore, the refinement of the plating structure reduces the concentration of stress in the plating layer 23 during bending, thereby suppressing the occurrence of large cracks and the like, thereby further improving bending workability. In order to exhibit the said effect | action, it is preferable that the sum total of content of Ti and B in the hot dipping bath 2 is the range of 0.0005 to 0.1% by mass ratio. The total content of Ti and B is particularly preferably 0.001% or more. The total content of Ti and B is particularly preferably 0.05% or less. In particular, the total content of Ti and B is preferably in the range of 0.001 to 0.05%.

  The plating layer 23 is formed by a hot dipping process using such a hot dipping bath 2. In the plating layer 23, Mg concentration in the surface layer is suppressed as described above. Thereby, as described above, the Mg content may be less than 60% by mass in any region having a diameter of 4 mm and a depth of 50 nm in the outermost layer 50 nm deep from the surface of the plating layer 23. preferable. In this case, the amount of the Mg-based oxide film in the outermost layer of the plating layer 23 is particularly reduced, and wrinkles due to the Mg-based oxide film are further suppressed. As the Mg content in the outermost layer decreases, wrinkles due to the Mg-based oxide film are suppressed. The Mg content is more preferably less than 40% by mass, even more preferably less than 20% by mass, and particularly preferably less than 10% by mass. In particular, in the outermost layer having a thickness of 50 nm of the plating layer 23, it is preferable that there is no portion where the Mg content is 60% by mass or more, and it is preferable that there is no portion where the Mg content is 40% by mass or more. More preferably, there is no portion where the Mg content is 20% by mass or more.

  The physical meaning of the Mg content will be described. The Mg content in the stoichiometric MgO oxide is about 60% by mass. That is, when the Mg content is less than 60% by mass, the stoichiometric composition of MgO (MgO alone oxide film) is not present in the outermost layer of the plating layer 23, or the formation of MgO having the stoichiometric composition. Means that is significantly suppressed. In the present embodiment, excessive oxidation of Mg in the outermost layer of the plating layer 23 is suppressed, thereby suppressing the formation of an oxide film of MgO alone. In the outermost layer of the plating layer 23, a composite oxide containing a small amount or a large amount of an oxide of an element other than Mg such as Al, Zn, Sr, etc. is formed. Is thought to have declined.

  The Mg content in the outermost layer of the plating layer 23 can be analyzed using a glow discharge emission spectrometer. When it is difficult to obtain an accurate quantitative concentration analysis value, an oxide film of MgO alone is recognized as the outermost layer of the plating layer 23 by comparing the concentration curves of a plurality of elements included in the plating layer 23. Just make sure you don't.

  The volume ratio of the Si—Mg phase in the plating layer 23 is preferably in the range of 0.2 to 15% by volume. The volume ratio of the Si—Mg phase is more preferably 0.2 to 10%, further preferably 0.3 to 8%, and particularly preferably 0.4 to 5%. When the Si—Mg phase is present in the plating layer 23 as described above, Mg at the time of forming the plating layer is sufficiently taken into the Si—Mg phase, and the flow of the molten plating metal is sufficiently inhibited by the Si—Mg phase. Further, the generation of wrinkles in the plating layer 23 is further suppressed.

  In the hot-dipped steel material, as described above, wrinkles on the surface of the plating layer 23 are suppressed, and in particular, the surface of the plating layer 23 has a bulge with a height greater than 200 μm and a steepness greater than 1.0. Preferably it no longer exists. The steepness is a value defined by (height of the ridge (μm)) ÷ (width of the bottom of the ridge (μm)). The bottom surface of the ridge is a portion where a virtual plane including a flat surface around the ridge and the ridge intersect. The height of the ridge is the height from the bottom of the ridge to the tip of the ridge. When the steepness is low, the appearance of the plating layer 23 is further improved. Furthermore, when the coating ground treatment layer 24 is formed over the plating layer 23 as described later, the ridge is prevented from breaking through the coating ground treatment layer 24, and the thickness of the coating ground treatment layer 24 is reduced. It can be easily uniformized. As a result, the appearance of the painted hot-dip plated steel material is improved, and the painted hot-dip plated steel material can exhibit further excellent corrosion resistance and the like due to the 24 coating base treatment layers.

  Such adjustment of the degree of Mg concentration, the state of the Si-Mg phase, the thickness of the alloy layer 26, and the steepness of the bulge of the surface of the plating layer 23 can be achieved by using the hot-dip plating bath 2 having the above composition for the steel material 1. It can be achieved by applying a hot dipping process.

  In the hot dipping process, the steel layer 1 on which the pre-plating layer 27 containing at least one component selected from Cr, Mn, Fe, Co, Ni, Cu, Zn, and Sn is formed is formed to form a plating layer. The hot dipping process may be performed. The pre-plating process 27 is formed on the surface of this steel material 1 by performing the pre-plating process to the steel material 1 before performing the said hot dipping process. The pre-plated layer 27 improves the wettability between the steel material 1 and the hot-dip plated metal during the hot-dipping process, and improves the adhesion between the steel material 1 and the plated layer 23.

  The pre-plating layer 27 depends on the type of metal constituting the pre-plating layer 27, but contributes to further improvement in the surface appearance and corrosion resistance of the plating layer 23. For example, when the pre-plating layer 27 containing Cr is formed, the formation of the alloy layer 26 containing Cr is promoted between the steel material 1 and the plating layer 23, and the corrosion resistance of the hot-dip plated steel material is further improved. For example, when the pre-plated layer 27 containing Fe or Ni is formed, the wettability between the steel material 1 and the hot-dip plated metal is improved, the adhesion of the plated layer 23 is greatly improved, and the precipitation of the Si—Mg phase is further improved. The surface appearance of the plating layer 23 is further improved. The acceleration of the precipitation of the Si—Mg phase is considered to occur due to the reaction between the pre-plated layer 27 and the hot-dip plated metal.

Although the adhesion amount of the pre-plating layer 27 is not specifically limited, It is preferable that the adhesion amount on the one surface of the steel material 1 is 0.1-3 g / m < ² >. If this adhesion amount is less than 0.1 g / m ² , it is difficult to cover the surface of the steel material with the pre-plating layer 27, and the improvement effect by the pre-plating is not sufficiently exhibited. Moreover, when this adhesion amount exceeds 3 g / m < ² >, not only the improvement effect is saturated but also the manufacturing cost becomes high.

  Below, the outline | summary of the hot dipping process apparatus for performing the hot dipping process with respect to the steel material 1, and the suitable process conditions of a hot dipping process are demonstrated.

  The steel material 1 to be treated is a member made of steel such as carbon steel, alloy steel, stainless steel, nickel chrome steel, nickel chrome molybdenum steel, chrome steel, chrome molybdenum steel, and manganese steel. Examples of the steel material 1 include various members such as a thin steel plate, a thick steel plate, a die steel, a steel pipe, and a steel wire. That is, the shape of the steel material 1 is not particularly limited.

  The steel material 1 may be subjected to a flux treatment before the hot dipping treatment. By this flux treatment, the wettability and adhesion of the steel material 1 to the hot dipping bath 2 can be improved. The steel material 1 may be subjected to a heat annealing / reduction treatment before being immersed in the hot dipping bath 2, or this treatment may be omitted. As described above, the steel material 1 may be pre-plated before the hot dipping process.

  Below, the manufacturing process of the hot dipped steel material (hot-dipped steel plate) when a plate material (steel plate 1a) is adopted as the steel material 1, that is, when a hot-dipped steel plate is manufactured will be described.

  The hot dipping treatment apparatus shown in FIG. 1 includes a transport device that continuously transports the steel plate 1a. The transport device includes a feeder 3, a winder 12, and a plurality of transport rolls 15. In this conveying apparatus, the feeder 3 holds the coil 13 (first coil 13) of the long steel plate 1a. The first coil 13 is unwound by the feeding machine 3, and the steel plate 1 a is conveyed to the winder 12 while being supported by the conveyance roll 15. Furthermore, the winder 12 winds the steel plate 1a, and the winder 12 holds the coil 14 (second coil 14) of the steel plate 1a.

  In this hot dipping apparatus, the heating furnace 4, annealing / cooling section 5, snout 6, pot 7, injection nozzle 9, cooling device 10, temper rolling, Shape correction devices 11 are sequentially provided. The heating furnace 4 heats the steel plate 1a. The heating furnace 4 is constituted by a non-oxidizing furnace or the like. The annealing / cooling unit 5 heat-anneales the steel sheet 1a and subsequently cools it. The annealing / cooling section 5 is connected to the heating furnace 4, and an annealing furnace is provided on the upstream side, and a cooling zone (cooler) is provided on the downstream side. The annealing / cooling section 5 is maintained in a reducing atmosphere. The snout 6 is a cylindrical member in which the steel plate 1 a is conveyed. One end of the snout 6 is connected to the annealing / cooling unit 5 and the other end is disposed in the hot dipping bath 2 in the pot 7. The inside of the snout 6 is maintained in a reducing atmosphere as in the annealing / cooling section 5. The pot 7 is a container for storing the hot dipping bath 2, and a sink roll 8 is disposed therein. The injection nozzle 9 injects gas toward the steel plate 1a. The injection nozzle 9 is disposed above the pot 7. The injection nozzle 9 is disposed at a position where gas can be injected toward both surfaces of the steel plate 1 a pulled up from the pot 7. The cooling device 10 cools the hot dip plated metal adhering to the steel plate. As the cooling device 10, an air cooler, a mist cooler, or the like is provided, and the steel plate 1 a is cooled by the cooling device 10. The temper rolling / shape correction apparatus 11 performs temper rolling and shape correction of the steel sheet 1a on which the plating layer 23 is formed. The temper rolling / shape correcting apparatus 11 includes a skin pass mill for performing temper rolling on the steel plate 1a, a tension leveler for performing shape correction on the steel plate 1a after temper rolling, and the like.

  In the hot dipping process using this hot dipping apparatus, the steel plate 1a is first unwound from the paying machine 3 and continuously drawn. After this steel plate 1a is heated in the heating furnace 4, it is transferred to the annealing / cooling section 5 in a reducing atmosphere and simultaneously annealed in the annealing furnace, and at the same time, removing rolling oil or the like adhering to the surface of the steel plate 1a. Then, after the surface is cleaned, such as reduction and removal of the oxide film, it is cooled in a cooling zone. Next, the steel plate 1 a passes through the snout 6 and further enters the pot 7 and is immersed in the hot dipping bath 2 in the pot 7. The steel plate 1a is supported by the sink roll 8 in the pot 7 so that its conveying direction is changed upward, and is drawn out from the hot dipping bath 2. Thereby, the hot dip metal adheres to the steel plate 1a.

Next, the amount of adhesion of the hot dipped metal adhering to the steel plate 1a is adjusted by injecting gas from the injection nozzle 9 onto both surfaces of the steel plate 1a. Such a method for adjusting the amount of adhesion by gas injection is called a gas wiping method. It is preferable that the adhesion amount of the hot dipped metal is adjusted to a range of 40 to 200 g / m ² by combining both surfaces of the steel plate 1a.

  Examples of the type of gas (wiping gas) injected to the steel sheet 1a in the gas wiping method include air, nitrogen, argon, helium, and water vapor. These wiping gases may be preheated and then injected to the steel sheet 1a. In this embodiment, by using the hot dipping bath 2 having a specific composition, the surface oxidation concentration of Mg in the hot dipped metal (oxidation of Mg on the surface of the hot dipped metal and an increase in the Mg concentration) is essentially suppressed. The Therefore, even if oxygen is included in the wiping gas or oxygen is included in the air flow accompanying the injection of the wiping gas, the plating adhesion amount (deposited on the steel plate 1a does not deteriorate the effect of the invention). It is possible to adjust the amount of hot-dip plated metal).

  Of course, the method for adjusting the plating adhesion amount is not limited to the gas wiping method, and various adhesion amount control methods can be applied. Examples of the adhesion amount control method other than the gas wiping method include a roll drawing method in which the steel plate 1a is passed between a pair of rolls arranged immediately above the bath surface of the hot dipping bath 2, and a steel plate 1a drawn from the hot dipping bath 2. A method in which a shielding plate is disposed in the vicinity and the hot-dip plated metal is wiped off by this shielding plate, and an electromagnetic force wiping method in which a force that moves downward using electromagnetic force is applied to the hot-dip plated metal adhering to the steel plate 1a. And a method of adjusting the plating adhesion amount by using natural gravity drop without applying external force. Two or more plating adhesion amount adjusting methods may be combined.

  Next, the steel plate 1a is transported further upward than the position where the injection nozzle 9 is disposed, and then supported by two transport rolls 15 so as to be folded downward. That is, the steel plate 1a is conveyed along an inverted U-shaped path. In this inverted U-shaped path, the steel plate 1a is cooled by the cooling device 10 by air cooling, mist cooling, or the like. Thereby, the hot-dip plated metal adhering to the surface of the steel plate 1a is solidified, and the plating layer 23 is formed.

  In order to complete the solidification of the hot-dipped metal by being cooled by the cooling device 10, the surface temperature of the hot-dipped metal (or the plating layer 23) is 300 ° C. or less by the cooling device 10 on the steel plate 1 a. It is preferable that it is cooled to. The surface temperature of the hot dip metal is measured with a radiation thermometer, for example. In order to form the plating layer 23 in this way, the cooling rate from when the steel plate 1a is drawn out from the hot dipping bath 2 until the surface of the hot dipped metal on the steel plate 1a is cooled to 300 ° C. A range of 5 to 100 ° C./sec is preferable. In order to control the cooling rate of the steel plate 1a, it is preferable that the cooling device 10 has a temperature control function for adjusting the temperature of the steel plate 1a along the conveying direction and the plate width direction. The cooling device 10 may be divided into a plurality along the conveying direction of the steel plate 1a. In FIG. 1, a primary cooling device 101 that cools the steel plate 1 a in a path that is transported further upward than the arrangement position of the injection nozzle 9, and a secondary cooling device 102 that cools the steel plate 1 a on the downstream side of the primary cooling device 101. And are provided. The primary cooling device 101 and the secondary cooling device 102 may be further divided into a plurality. In this case, for example, the primary cooling device 101 cools the steel plate 1a until the surface of the hot-dip metal reaches 300 ° C. or lower, and the secondary cooling device 102 further heats the steel plate 1a to the temper rolling / shape correcting device 11. It can cool so that the temperature at the time of being introduced into may become 100 ° C or less.

  In the process of cooling the steel plate 1a, it is preferable that the cooling rate of the surface of the hot dip metal on the steel plate 1a is 50 ° C./sec or lower while the surface temperature of the hot dip metal is 500 ° C. or higher. In this case, the precipitation of the Si—Mg phase on the surface of the plating layer 23 is particularly suppressed, so that the occurrence of sagging is suppressed. The reason why the cooling rate in this temperature range affects the precipitation behavior of the Si-Mg phase is not necessarily clear at this time, but if the cooling rate in this temperature range is fast, the temperature gradient in the thickness direction of the hot-dip plated metal becomes large. For this reason, the precipitation of the Mg—Si layer is promoted preferentially on the surface of the hot-dip plated metal at a lower temperature, and as a result, the precipitation amount of the Si—Mg phase on the outermost surface of the plating increases. It is done. The cooling rate in this temperature range is more preferably 40 ° C./sec or less, and particularly preferably 35 ° C./sec or less.

  The cooled steel sheet 1a is subjected to temper rolling by the temper rolling / shape correcting device 11 and then subjected to shape correction. The rolling reduction by temper rolling is preferably in the range of 0.3 to 3%. It is preferable that the elongation rate of the steel sheet 1a by shape correction is 3% or less.

  Subsequently, the steel plate 1a is wound up by the winder 12, and the coil 14 of the steel plate 1a is held by the winder 12.

  At the time of such a hot dipping process, the temperature of the hot dipping bath 2 in the pot 7 is a temperature not higher than the solidification start temperature of the hot dipping bath 2 and 40 ° C. higher than the start solidification temperature. Is preferred. More preferably, the temperature of the hot dipping bath 2 in the pot 7 is a temperature not higher than the solidification start temperature of the hot dipping bath 2 and not higher than 25 ° C. above the solidification start temperature. When the upper limit of the temperature of the hot dipping bath 2 is limited in this way, the time required for the hot dipped metal adhering to the steel plate 1a to solidify after the steel plate 1a is drawn from the hot dipping bath 2 is shortened. . As a result, the time during which the hot-dip plated metal adhering to the steel plate 1a is in a flowable state is also shortened, so that wrinkles are less likely to occur in the plated layer 23. If the temperature of the hot dipping bath 2 is not higher than 20 ° C. higher than the solidification start temperature of the hot dipping bath 2, the generation of wrinkles in the plating layer 23 is remarkably suppressed.

  When the steel plate 1a is drawn out from the hot dipping bath 2, it may be drawn into a non-oxidizing atmosphere or a low-oxidizing atmosphere, and gas is further applied to the steel plate 1a in this non-oxidizing atmosphere or low-oxidizing atmosphere. Adjustment of the adhesion amount of the hot dip metal by the wiping method may be performed. For that purpose, for example, as shown in FIG. 2, the steel material 1 drawn from the hot dipping bath 2 has a transport path upstream of the hot dipping bath 2 (a transport path going upward from the hot dipping bath 2). It is preferable that the hollow member 22 is surrounded and the inside of the hollow member 22 is filled with a non-oxidizing gas such as nitrogen gas or a low oxidizing gas. A non-oxidizing gas or a low oxidizing gas means a gas having a lower oxygen concentration than the atmosphere. The oxygen concentration of the non-oxidizing gas or the low oxidizing gas is preferably 1000 ppm or less. The atmosphere filled with the non-oxidizing gas or the low oxidizing gas is a non-oxidizing atmosphere or a low oxidizing atmosphere. In this atmosphere, the oxidation reaction is suppressed. The injection nozzle 9 is disposed inside the hollow member 22. The hollow member 22 is provided so as to surround the conveyance path of the steel material 1 from the inside of the hot dipping bath 2 (upper part of the hot dipping bath 2) to the upper side of the hot dipping bath 2. Further, the gas injected from the injection nozzle 9 is also preferably a non-oxidizing gas such as nitrogen gas or a low oxidizing gas. In this case, since the steel plate 1a drawn from the hot dipping bath 2 is exposed to a non-oxidizing atmosphere or a low oxidizing atmosphere, the oxidation of the hot dipped metal adhering to the steel plate 1a is suppressed, and the surface layer of this hot dipped metal is suppressed. Further, the Mg-based oxide film is more difficult to be formed. For this reason, generation | occurrence | production of the wrinkle in the plating layer 23 is further suppressed. Instead of using the hollow member 22, even if a part of the hot dipping apparatus including the conveying path of the steel plate 1 a or the whole hot dipping apparatus is arranged in a non-oxidizing atmosphere or a low-oxidizing atmosphere. Good.

  It is also preferable that an overaging treatment is further performed on the steel plate 1a after the hot dipping treatment. In this case, the workability of the hot dipped steel is further improved. The overaging treatment is performed by holding the steel sheet 1a within a certain temperature range for a certain time.

  3A and 3B show an apparatus used for overaging treatment, and FIG. 3A shows a heating apparatus. FIG. 3B shows the heat retaining container 20. A heating apparatus is provided with the conveying apparatus with which the steel plate 1a after a hot dipping process is conveyed continuously. Similar to the conveying device in the hot dipping treatment apparatus, the conveying device includes a feeding machine 16, a winder 17, and a plurality of conveying rolls 21. A heating furnace 18 such as an induction heating furnace is provided in the transport path of the steel plate 1a by the transport device. The heat retaining container 20 is not particularly limited as long as it can hold the coil 19 of the steel plate 1a and has heat insulation. The heat retaining container 20 may be a large container (a warming chamber).

  When the steel plate 1a is over-aged, the coil 14 of the steel plate 1a after the hot dipping treatment is first transported from the winder 12 of the hot dipping treatment device by a crane, a carriage, or the like, and the heating device 16 is fed. Retained. In the heating device, the steel plate 1a is first unwound from the feeder 16 and continuously fed out. The steel plate 1a is heated to a temperature suitable for the overaging treatment in the heating furnace 18, and then wound up by the winder 17, and the coil 19 of the steel plate 1a is held by the winder 17.

  Subsequently, the coil 19 of the steel plate 1 a is transported from the winder 17 by a crane, a carriage, or the like and held in the heat retaining container 20. Since the coil 19 of the steel plate 1a is held in the heat retaining container 20 for a certain period of time, the overaging treatment is performed on the steel plate 1a.

  The plating layer 23 formed on the surface of the steel plate 1a according to the present embodiment contains Mg, and a slight amount of Mg-based oxide film is present on the surface of the plating layer 23. Therefore, in the coil of the steel plate 1a during overaging treatment, Even if the plating layers 23 are overlapped with each other, seizure and welding hardly occur between the plating layers 23. For this reason, even if the heat retention time at the time of the overaging treatment is long, or even if the heat retention temperature is high, seizure hardly occurs, and sufficient overaging treatment can be performed on the steel sheet 1a. This greatly improves the workability of the hot-dip galvanized steel sheet and improves the efficiency of the overaging treatment.

In the overaging treatment, in particular, the temperature of the steel plate 1a after being heated by the heating device is in the range of 180 to 220 ° C., that is, the steel plate is in the temperature keeping container from the outside of the heat retaining container in the state where the temperature of the steel plate 1a is within the above range. Is preferably transferred to. It is preferable that the retention time y (hr) of the steel plate 1a in the heat insulation container satisfies the following formula (5).
5.0 × 10 ²² × t ^−10.0 ≦ y ≦ 7.0 × 10 ²⁴ × t ^−10.0 (5)
(However, 150 ≦ t ≦ 250)
In the formula (5), t (° C.) is the temperature (holding temperature) of the steel plate 1a during the holding time y (hr), and is the lowest temperature when temperature fluctuation occurs in the steel plate 1a.

  In the present embodiment, the hot dip treatment apparatus and the heating device are separate devices, but the hot dip treatment apparatus may include the heating furnace 18 so that the hot dip treatment apparatus may also serve as the heating device. In these apparatuses, the design may be changed as appropriate by adding, removing, or replacing various elements as necessary. Although the hot dip treatment apparatus and the heating apparatus according to the present embodiment are suitable when the steel material 1 is the steel plate 1a, the design of the hot dip treatment apparatus, the heating apparatus, and the like can be variously changed according to the shape of the steel material 1 and the like. is there. When the pretreatment for plating is performed on the steel material 1, the pretreatment for plating can be variously changed according to the type, shape and the like of the steel material 1.

[Production method of painted hot-dip galvanized steel]
The coated plated steel material according to each embodiment of the present invention is manufactured by forming the above-described painted base treatment layer 24 and the organic coating layer 25 on the upper layer of the steel material that has been subjected to the above-described hot dipping treatment. When the pretreatment layer 28 is provided, the pretreatment layer 28 is formed on the steel material that has been subjected to the above-described hot dipping treatment, and the coating base treatment layer 24 is laminated on the surface of the pretreatment layer 28. . Here, when forming the coating base treatment layer 24 and the pretreatment layer 28, after the coating agent for forming the pretreatment layer 28 is applied onto the plated steel material and dried and baked, the pretreatment layer 28 is formed. Alternatively, a coating composition for forming the coating base treatment layer 24 may be applied onto the pretreatment layer 28 and dried and baked. In addition, after the coating composition for forming the coating base treatment layer 24 and the coating agent for forming the pretreatment layer 28 are applied to the substrate-plated steel material by wet-on-wet or multi-layer simultaneous application, all the coating compositions are simultaneously dried. It may be baked.

  In addition, before forming the pretreatment layer 28 or the coating base treatment layer 24, the plating layer 23 may be subjected to nickel plating treatment, cobalt plating treatment, etc., washing with pure water or various organic solvent liquids, Cleaning with an aqueous solution or various organic solvent liquids optionally containing acid, alkali, or various etching agents may be performed. When the surface of the plating layer 23 is washed in this way, a small amount of Mg-based oxide film is present on the surface layer of the plating layer 23, or inorganic and organic stains are adhered to the surface of the plating layer 23. However, the Mg-based oxide film, dirt, and the like are removed from the plating layer 23, and thereby the adhesion between the plating layer 23 and the pretreatment layer 28 or the coating ground treatment layer 24 can be improved. Below, the detail of the formation method of the coating ground treatment layer 24, the pretreatment layer 28, and the organic coating layer 25 is described.

<Formation method of the coating ground treatment layer 24>
The method for forming the coating ground treatment layer 24 is not particularly limited. For example, the paint contains one or more selected from an organic resin, a silane coupling agent, a zirconium compound, and a titanium compound in an aqueous solvent or an organic solvent solvent. It can form by apply | coating a composition on plating steel materials and heat-drying. When a treatment agent using an aqueous solvent (hereinafter abbreviated as “aqueous treatment agent”) is used, a treatment agent using an organic solvent solvent (hereinafter abbreviated as “organic solvent treatment agent”) is used. This eliminates the need to pass an extra line for painting, which can greatly reduce manufacturing costs and significantly reduce emissions of volatile organic compounds (VOC). Therefore, it is preferable to use an aqueous treatment chemical. Here, the aqueous solvent used in the aqueous treatment chemical means that water is a solvent that is a main component of the solvent. The amount of water in the solvent is preferably 50% by mass or more. Solvents other than water may be organic solvents, but those containing organic solvents as defined in the Occupational Safety and Health Act organic solvent poisoning prevention regulations (Organic solvents listed in Schedule 6-2 of the Ordinance for Enforcement of the Industrial Safety and Health Act) More preferably 5% of the weight). The organic solvent-based solvent means that the organic solvent is a solvent that is a main component of the solvent.

  The treatment chemical for forming the coating ground treatment layer 24 is not limited to a specific method, and can be obtained by any method. As an example, a preferable treatment agent will be described as an example. A method of adding a constituent component of the coating base treatment layer 24 to an aqueous solvent or an organic solvent solvent as a dispersion medium, stirring with a disper, and dissolving or dispersing. It is done. When the dispersion medium is an aqueous solvent, a known hydrophilic solvent, for example, ethanol, isopropyl alcohol, t-butyl alcohol, propylene glycol, or the like is used as necessary to improve the solubility or dispersibility of each component. Alcohols, cellosolves such as ethylene glycol monobutyl ether and ethylene glycol monoethyl ether, esters such as ethyl acetate and butyl acetate, and ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone may be added.

  The method for applying the treatment agent to the plated steel material is not particularly limited, and any known method can be used. For example, roll coating, curtain coating, spray coating, bar coating, dipping, electrostatic coating, or the like can be used as a coating method.

  The heating and drying method for forming the coating base treatment layer 24 from the treatment chemical is not particularly limited and can be performed by any method. For example, the plating steel material can be heated in advance before applying the treatment agent, the plating steel material can be heated after application, or a combination thereof can be used for drying. There is no restriction | limiting in particular also in a heating method, A processing chemical | medical agent can be dried and baked using hot air, induction heating, near infrared rays, a direct fire, etc. individually or in combination. The dry baking temperature is preferably 60 ° C. to 250 ° C., most preferably 80 ° C. to 150 ° C. in terms of ultimate plate temperature. When the ultimate plate temperature is less than 60 ° C., the film formation of the coating film and the desorption of the solvent component are insufficient, and the corrosion resistance and the adhesion with the plating layer 23 or the organic coating layer 25 may be insufficient. If it exceeds 250 ° C., the bake-curing becomes excessive, or the coating ground treatment layer 24 is oxidized more than necessary, resulting in insufficient corrosion resistance and adhesion with the plating layer 23 or the organic coating layer 25. There is. The drying baking time (heating time) is preferably 1 second to 60 seconds, and more preferably 3 seconds to 20 seconds. If the dry baking time is less than 1 second, the film formation of the coating film and the desorption of the solvent component are insufficient, and the corrosion resistance and the adhesion with the plating layer 23 or the organic coating layer 25 may be insufficient. If it exceeds 2 seconds, the productivity decreases.

<Formation method of the organic coating layer 25>
A method for forming the organic coating layer 25 is not particularly limited. For example, a coating containing a binder resin or a precursor thereof, a color pigment, and an antirust pigment in an aqueous solvent or an organic solvent solvent is applied onto the plated steel material. , Heating, irradiation with energy such as ultraviolet rays, volatilization of the solvent, or a combination of two or more of the following means. When using paints that use water-based solvents (hereinafter abbreviated as “water-based paints”), paint-only lines for using paints that use organic solvent-based solvents (hereinafter abbreviated as “organic solvent-based paints”) There is a possibility that it will not be necessary to pass an extra plate, in which case the manufacturing cost can be greatly reduced and the emission of volatile organic compounds (VOC) can be greatly suppressed. It is preferable to use a water-based paint because there is a merit in the above. Here, the aqueous solvent used in the aqueous coating means that water is a solvent that is a main component of the solvent. The amount of water in the solvent is preferably 50% by mass or more. Solvents other than water may be organic solvents, but those containing organic solvents as defined in the Occupational Safety and Health Act organic solvent poisoning prevention regulations (Organic solvents listed in Schedule 6-2 of the Ordinance for Enforcement of the Industrial Safety and Health Act) More preferably 5% of the weight). The organic solvent-based solvent means that the organic solvent is a solvent that is a main component of the solvent.

  The coating material for forming the organic coating layer 25 is not limited to a specific method, and can be obtained by any method. As an example, a preferable coating material will be described as an example. A method of adding a constituent component of the organic coating layer 25 to an aqueous solvent or an organic solvent solvent that is a dispersion medium, stirring with a disper, and dissolving or dispersing. When the dispersion medium is an aqueous solvent, a known hydrophilic solvent, for example, ethanol, isopropyl alcohol, t-butyl alcohol, propylene glycol, or the like is used as necessary to improve the solubility or dispersibility of each component. Alcohols, cellosolves such as ethylene glycol monobutyl ether and ethylene glycol monoethyl ether, esters such as ethyl acetate and butyl acetate, and ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone may be added.

  The method for applying the paint is not particularly limited, and any known method can be used. For example, roll coating, curtain coating, spray coating, bar coating, dipping, electrostatic coating, or the like can be used as a coating method. When the coating is a powder coating, powder coating, electrostatic powder coating, fluidized bed coating, or the like can be used.

  The curing / film formation method for forming the organic coating layer 25 from a paint is not particularly limited and can be performed by any method. For example, the plated steel material is heated in advance before the coating composition is applied, or the plated steel material is heated after the application, or a combination thereof. Furthermore, irradiation with energy such as ultraviolet rays, solvent volatilization, or Curing and film formation can be performed by a combination of two or more of any of these means. There is no restriction | limiting in particular also in a heating method, A coating material can be dried and baked using hot air, induction heating, near infrared rays, a direct fire, etc. individually or in combination. In the case of performing curing and film formation by heating, the drying baking temperature is preferably 100 ° C to 250 ° C in terms of ultimate plate temperature, more preferably 120 ° C to 230 ° C, and 130 ° C to 220 ° C. Is most preferred. If the ultimate plate temperature is less than 100 ° C., the coating film is not sufficiently formed, and the corrosion resistance, scratch resistance, and contamination resistance may decrease. If it exceeds 250 ° C., bake hardening will be excessive. Corrosion resistance may decrease. The drying baking time (heating time) is preferably 1 second to 60 seconds, and more preferably 3 seconds to 20 seconds. When the dry baking time is less than 1 second, the coating film is not sufficiently formed, and the corrosion resistance, scratch resistance, and stain resistance may decrease. If it exceeds 60 seconds, the productivity decreases.

<Method for Forming Pretreatment Layer 28>
The pretreatment layer 28 is formed by applying a coating agent for forming the pretreatment layer 28 to at least one surface of the plated steel material and drying by heating. Although there is no restriction | limiting in particular in the coating method of a coating agent, Well-known roll coating, spray coating, bar coating, immersion, electrostatic coating, etc. can be used suitably. There is no restriction | limiting in particular in the baking drying method, A plating steel material is heated previously, a plating steel material is heated after application | coating, or you may dry combining these. There is no restriction | limiting in particular in a heating method, A hot air, induction heating, near infrared rays, a direct fire, etc. can be used individually or in combination. About baking baking temperature, it is preferable that it is 60 to 150 degreeC by ultimate temperature. If the ultimate temperature is less than 60 ° C, drying may be insufficient, and the adhesion between the coating film and the base-plated steel material or the corrosion resistance of the coating-plated steel material may be reduced. Adhesion with the base-plated steel may be reduced. A more preferable ultimate temperature is 70 ° C to 130 ° C.

  The coated plated steel material produced according to the present embodiment has an appearance that is less than the conventional high Al content and Mg content plated steel material because the plating surface unevenness caused by wrinkles and sagging of the plated layer 23 is suppressed. Is good. In addition, due to the effect of the coating base treatment layer 24, the corrosion resistance of the scratched portion of the painted surface and the processed portion in which the base steel material is deformed, which has not been considered in the conventional high Al-containing and Mg-containing plated steel materials, is also excellent. . Furthermore, it is excellent in white rust resistance when it is heated and when it is irradiated with ultraviolet rays after long-term use.

  This coated plated steel material can be used for building materials, materials for automobiles, materials for household electrical appliances, and other various applications, and can be suitably used particularly for applications requiring processed portion corrosion resistance.

  FIG. 11A to FIG. 11H show the layer structure of the coated plated steel material in the embodiment of the present invention. FIG. 11A shows a layer structure formed by the steel material 1, the plating layer 23, the coating ground treatment layer 24, and the organic coating layer 25. FIG. 11B shows a layer structure formed of the steel material 1, the alloy layer 26, the plating layer 23, the coating ground treatment layer 24, and the organic coating layer 25. FIG. 11C shows a layer structure formed by the steel material 1, the pre-plating layer 27, the plating layer 23, the coating ground treatment layer 24, and the organic coating layer 25. FIG. 11D shows a layer structure formed by the steel material 1, the plating layer 23, the pretreatment layer 28, the coating ground treatment layer 24, and the organic coating layer 25. FIG. 11E shows a layer structure formed of the steel material 1, the pre-plated layer 27, the alloy layer 26, the plated layer 23, the coating ground treatment layer 24, and the organic coating layer 25. FIG. 11F shows a layer structure formed by the steel material 1, the alloy layer 26, the plating layer 23, the pretreatment layer 28, the coating base treatment layer 24, and the organic coating layer 25. FIG. 11G shows a layer structure formed by the steel material 1, the pre-plating layer 27, the plating layer 23, the pretreatment layer 28, the coating ground treatment layer 24, and the organic coating layer 25. FIG. 11H shows a layer structure formed by the steel material 1, the pre-plated layer 27, the alloy layer 26, the plated layer 23, the pretreatment layer 28, the coating ground treatment layer 24, and the organic coating layer 25.

  The invention is further illustrated by examples using hot dip plated steel sheets. However, the present invention is not limited to the following examples.

(1) Hot dipped steel sheet (hot dipped steel)
First, a method for producing a hot-dip galvanized steel sheet, an evaluation test method for the hot-dip galvanized steel sheet obtained, and a test result will be described.

[1.1. Method for producing hot-dip galvanized steel sheet]
As the steel material 1, a long steel plate 1a (made of low carbon aluminum killed steel) having a thickness of 0.80 mm and a width of 1000 mm was used. The steel sheet 1a was subjected to a hot dipping process using the hot dipping apparatus shown in FIG. The processing conditions are as shown in Tables 1 to 3. The solidification start temperature shown in Tables 1 to 3 is a value derived from the liquid phase curve of the phase diagram of the Zn-Al binary bath, and Al in each hot dipping bath composition shown in Tables 1 to 3 It is a value corresponding to the content. In levels M68 and M69, Ni pre-plating was performed before steel plate 1a was hot-plated, so that level M68 had an adhesion amount (single side) of 0.5 g / m ² , and level M69 had an adhesion amount (single side) ) A pre-plated layer 27 of 2.0 g / m ² was formed. In the level M70, the Zn-10% Cr pre-plating process was performed and the pre-plating layer 27 of the adhesion amount (one side) 1.0g / m < ² > was formed. In other examples and comparative examples, no pre-plating treatment was performed.

  The temperature at the time of penetration of the steel plate 1a into the hot dipping bath 2 was 580 ° C. When the steel plate 1a was pulled out from the hot dipping bath 2, it was pulled out in an air atmosphere and gas wiping was also performed in the air atmosphere. However, for level M71, the transport path of the steel plate 1a upstream from the hot dipping bath 2 is surrounded by a seal box (hollow member 22), and an injection nozzle 9 is disposed inside the seal box. The inside was made into a nitrogen atmosphere, and gas wiping with nitrogen gas was performed inside the hollow member 22.

  In the cooling device 10, the steel plate 1a was cooled until the surface temperature of the hot dipped metal (plating layer 23) reached 300 ° C. The cooling rate during cooling was 45 ° C./sec. However, for the levels M76 and M77, the cooling rate in the temperature range where the surface temperature of the hot-dip plated metal is 500 ° C. or higher is changed, and in this process, the cooling rate at the level M76 is 38 ° C./sec. The cooling rate was 28 ° C./sec.

  The rolling reduction during temper rolling was 1%, and the elongation of the steel sheet 1a during shape correction was 1%.

[1.2. Evaluation test of hot dipped steel sheet]
The following evaluation test was performed on the hot-dip galvanized steel sheet obtained by producing the hot-dip galvanized steel sheet.

(1.2.1. Volume ratio evaluation of Si-Mg phase)
Samples were obtained by cutting the hot-dip plated steel sheet in the thickness direction. The sample was embedded in resin so that the cut surface was exposed, and then the cut surface was polished into a mirror surface. When this cut surface was observed with an electron microscope, a state in which the Si—Mg phase was distributed in the plating layer 23 clearly appeared on the cut surface.

  FIG. 4A shows an image obtained by photographing the cut surface of the hot-dip steel sheet obtained at level M5 with an electron microscope. Furthermore, the elemental analysis was performed about the part by which precipitation of Si-Mg phase was recognized using the energy dispersive X-ray analyzer (EDS). The result is shown in FIG. 4B. According to this result, it can be seen that only two elements of Mg and Si are strongly detected. O (oxygen) is also detected because oxygen adsorbed on the sample was detected in the sample preparation stage.

  The area ratio (%) of the Si—Mg phase in the cut surface is measured by performing image analysis based on the captured image in a range where the length in the direction orthogonal to the thickness direction is 20 mm in the cut surface of the plating layer 23. did. Since the Si-Mg phase has a dark gray color tone and is clearly distinguished from other phases, it can be easily discriminated by image analysis.

  The volume ratio of the Si—Mg phase was evaluated assuming that the area ratio (%) obtained by this was the same as the volume ratio of the Si—Mg phase. The results are shown in Tables 4-6.

(1.2.2. Mass ratio evaluation of the amount of Mg in the Si-Mg phase with respect to the total amount of Mg)
From the above formulas (1) to (4), the mass ratio of the amount of Mg in the Si—Mg phase to the total amount of Mg in the plating layer 23 (the mass ratio of Mg in Tables 4 to 6) was calculated. The results are shown in Tables 4-6.

(1.2.3. Surface Mg amount evaluation)
Elemental analysis in the depth direction (thickness direction of the plated layer 23) of the components contained in the plated layer 23 in the hot-dip plated steel sheet was performed by glow discharge optical emission spectroscopy (GD-OES). In the measurement, the diameter of the measurement area is 4 mm, the output is 35 W, the measurement atmosphere is Ar gas, the measurement pressure is 600 Pa, the discharge mode is normal sputtering, Duty Cycle 0.1, the analysis time is 80 seconds, the sampling time is 0.02 sec / The emission intensity of the element contained in the plating layer 23 was measured under the condition of “point”. In order to convert the obtained emission intensity value into a quantitative concentration value (mass% concentration), elemental analysis of standard samples such as 7000 series Al alloys and steel materials with known component concentrations was also performed separately. In addition, since the GD-OES data is usually in the form of changes in the emission intensity with respect to the sputtering time, the sputter depth is measured by observing the cross section of the sample after the measurement is completed, and this sputter depth is divided by the total sputter time. Thus, the sputtering rate was calculated, and the depth position of the plating layer 23 in the GD-OES depth direction profile was specified.

  The analysis results for the level M5 and the level M50 are shown in FIGS. 5A and 5B, respectively. According to this, at the level M50, it can be confirmed that the Mg concentration in the surface layer of the plating layer 23 is rapidly increased.

  Based on this result, the Mg content in a region where the diameter is 4 mm and the depth is 50 nm in the outermost layer having a depth of 50 nm in the plating layer 23 was derived. The results are shown in Tables 4-6.

(1.2.4. Surface Cr content evaluation)
In the same manner as in the evaluation of the surface layer Mg amount, an integrated value of Cr emission intensity in a region having a diameter of 4 mm and a depth of 50 nm from the outermost surface of the plating layer 23 was measured by GD-OES. Similarly, the integrated value of the Cr emission intensity of the entire plating layer 23 was also measured, and the ratio of the integrated value of the Cr emission intensity in the region to this value was obtained. Based on the ratio of the integrated value of the Cr emission intensity and the chemical analysis value of the Cr amount of the entire plated layer 23 by ICP, the size is 4 mm in diameter and the depth is 50 nm from the outermost surface of the plated layer 23. The Cr content was calculated. The results are shown in Tables 4-6.

(1.2.5. Evaluation of the area ratio of the Si—Mg phase on the plating layer surface)
The surface of the plating layer 23 was observed with an electron microscope. A photograph of the surface of the plating layer 23 taken with an electron microscope for the level M5 is shown in FIG. According to this observation result, it can be confirmed that the Si—Mg phase is distributed on the surface of the plating layer 23. Based on this result, the area of the Si—Mg phase on the surface of the plating layer 23 was measured, and based on this, the area ratio of the Si—Mg phase on the surface of the plating layer 23 was calculated. The results are shown in Tables 4-6.

(1.2.6. Evaluation of Alloy Layer 26)
Samples were obtained by cutting the hot-dip plated steel sheet in the thickness direction. The sample was embedded in resin so that the cut surface was exposed, and then the cut surface was polished into a mirror surface. On this cut surface, an alloy layer 26 present at the interface between the plating layer 23 and the steel plate 1a appeared. The thickness of the alloy layer 26 was measured. Further, a 10 μm × 20 μm portion of the polished surface was sampled from the polished surface with a focused ion beam apparatus, and a micro sample processed to a thickness of 50 nm or less was produced. With respect to this micro sample, the Cr concentration in the alloy layer 26 was quantitatively analyzed using an energy dispersive X-ray analyzer (EDS) under the conditions of an acceleration voltage of 200 kV and a probe diameter of 1 nm.

  Based on this result, the ratio of the mass ratio of Cr in the alloy layer 26 to the mass ratio of Cr in the plating layer 23 was calculated (Cr content ratio in Tables 4 to 6). The results are shown in Tables 4-6.

(1.2.7. Appearance evaluation)
The appearance of the surface of the plating layer 23 in the hot dip plated steel sheet was observed visually and with an optical microscope. FIG. 7A shows a photograph of the surface of the plating layer 23 at level M5. FIG. 7B shows a photograph of the surface of the plating layer 23 at level M10. FIG. 8A shows an optical micrograph of the surface of the plating layer 23 at the level M62. FIG. 8B shows an optical micrograph of the surface of the plating layer 23 at the level M5. FIG. 9 shows a photograph of the appearance of the plating layer 23 at the level M50.

Based on this observation result, the degree of wrinkles on the surface of the plating layer 23 was evaluated according to the following criteria. The results are shown in Tables 4-6. In addition, since the degree of unevenness due to wrinkles, sagging, dross adhesion, and spangle size on the surface of the plated layer 23 observed in this observation result is also reflected in the surface of the coated plated steel material, this observation result is It can also be taken as a state.
5: Wrinkles are not recognized.
4: Wrinkles are slight (wrinkles as shown in FIG. 7A).
3: Wrinkles are small (in the case of evaluation where the level of wrinkles is between 4 and 2).
2: Wrinkle is moderate (better than shown in FIG. 7B).
1: Wrinkles are remarkable (wrinkles as shown in FIG. 7B).

Furthermore, based on this observation result, the degree of sagging on the surface of the plating layer 23 was evaluated according to the following criteria. The results are shown in Tables 4-6.
2: Sagging is not recognized.
1: Sagging is observed (sagging as shown in FIG. 9).

Furthermore, based on this observation result, the degree of dross adhering to the plating layer 23 was evaluated according to the following criteria. The results are shown in Tables 4-6.
2: There is no adhesion of dross with unevenness on the surface of the plating layer 23, or adhesion of dross with unevenness is recognized at less than 5 locations per 1 m ² .
1: The adhesion of dross with unevenness is observed on the surface of the plating layer 23 at 5 or more per 1 m ² .

  Furthermore, when the appearance characteristics of the plating layer 23 excluding wrinkles, sagging, and dross were observed, coarsening of spangles was observed at the level M78 (see other columns in Table 6).

(1.2.8. Overaging treatment evaluation)
The coil of the hot-dip plated steel sheet of level M5 was subjected to overaging treatment by changing the heat retention temperature t (° C.) and the heat retention time y (hr). The results were evaluated as follows.
3: Adhesion did not occur between the plating layers in the coil, and the workability was improved.
2: Adhesion does not occur between the plating layers in the coil, but the workability is not improved.
1: Adhesion occurred between the plating layers in the coil.

The result is shown in the graph of FIG. In this graph, the horizontal axis indicates the test conditions of the heat retention temperature t (° C.) and the vertical axis indicates the heat retention time y (hr). In this graph, the evaluation results for the heat retention temperature and the heat retention time are shown at positions corresponding to the heat retention temperature t (° C.) and the heat retention time y (hr) during the test. A region sandwiched by broken lines in the graph is a region where the heat retention temperature t (° C.) and the heat retention time y (hr) satisfy the following formula (5).
5.0 × 10 ²² × t ^−10.0 ≦ y ≦ 7.0 × 10 ²⁴ × t ^−10.0 (5)
(However, 150 ≦ t ≦ 250)

(2) Paint-plated steel material Next, a method for producing a paint-plated steel material, an evaluation test method for the paint-plated steel material obtained thereby, and test results will be described. Painted steel materials [1.1. It is prepared by forming the coating base treatment layer 24 and one or more organic coating layers 25 as the upper layer on the hot-dip steel plate prepared in [Method of manufacturing hot-dip steel plate].

[2.1. Preparation of coated plated steel]
(2.1.1. Formation of coating base treatment layer 24)
The coating composition for forming the coating ground treatment layer 24 includes an organic resin shown in Table 7, an organic silicon compound shown in Table 8, silica particles shown in Table 9, and a phosphoric acid compound (D) shown in Table 10. The tannin or tannate shown in Table 11, the etching fluoride and pretreatment layer 28 shown in Table 12, the zirconium compound and the titanium compound shown in Table 13 are blended in amounts (solid content) shown in Tables 19 to 28. And then agitation using a paint disperser. The surface of the hot dip plated steel sheet prepared in [1.1] is coated with a roll coater so as to have a predetermined adhesion amount, and is dried by heating to a predetermined ultimate plate temperature. A film of the treatment layer 24 was formed. Tables 19 to 28 also show the coating composition and coating amount of the coating base treatment layer 24 and the PMT (arrival plate temperature) applied to the coating base treatment layer 24. In some examples, the pretreatment layer 28 shown in Table 12 was formed. Of the organosilicon compounds shown in Table 8, B4 to B19 are BA / BE molar ratios shown in Table 8 when the amino group-containing silane coupling agent is BA and the epoxy group-containing silane coupling agent is BE. The molecular weights of the organosilicon compounds produced by the reaction are the molecular weights of the organosilicon compounds produced by the reaction.

(2.1.2. Coating composition for organic coating layer 25)
The coating composition for forming the organic coating layer 25 comprises a binder resin shown in Table 14, a color pigment shown in Table 15, and a rust preventive pigment shown in Table 16 in a blending amount (solid content) shown in Table 17. (Part by mass) and prepared by stirring using a disperser for paint. As needed, it diluted with the mixed solvent which mixed cyclohexanone and Solvesso 150 by mass ratio 1: 1, and adjusted to the viscosity which can be painted. In the following, when the organic coating layer 25 is composed of two or more layers, these organic coating layers 25 are referred to as a lower layer coating, an upper layer coating, and an uppermost layer coating in order from the coating base treatment layer 24 to form these layers. These paints are called the lower paint, the upper paint and the uppermost paint, respectively.

  Of the binder resins shown in Table 14, pellets, flakes, and sheet-shaped ones are used by dissolving in an organic solvent (a mixture of Esso Petroleum's Solvesso 150 and cyclohexanone in a mass ratio of 1: 1). did. To the polyester resins H1 and H2 of Table 14, 30% (mass% based on resin solids) of methylated melamine (Mitsui Cytec Co., Ltd.) was added as a melamine resin as a curing agent, and as a reaction catalyst, 1.0% (mass% based on the total resin solids) of Catalyst 602 manufactured by Mitsui Cytec Co., Ltd. was added.

(2.1.3. Painted steel)
The lower layer paint of (2.1.2) is applied to the upper layer of the coating ground treatment layer 24 formed in (2.1.1) with a roll coater so as to have a predetermined film thickness, and the arrival of the plated steel material It heat-dried on the conditions which plate | board temperature becomes 210 degreeC, and the lower layer film was formed. Next, the upper layer coating is applied to the upper layer of the lower layer coating with a roller curtain coater so as to have a predetermined film thickness, and is dried by heating under the condition that the reached plate temperature of the plated steel material is 230 ° C. Painted steel was obtained by forming a layer. In addition, when the organic film was composed of one layer, the formation procedure of the lower layer film was omitted. Table 18 shows the coating composition and the film thickness of the coating-plated steel material thus obtained.

  In the case of coated steel with three layers of organic coating, two types of upper layer paints are laminated on the upper layer of the lower coating of (2.1.3) above using a slide hopper curtain coater to reach the plated steel. The plate-plated steel material was obtained by heat-drying on the conditions which plate temperature becomes 230 degreeC, and forming the organic membrane which consists of three layers. In this case, the film disposed in the uppermost layer among the three organic film layers is referred to as the uppermost layer film, and the film disposed between the uppermost layer film and the lower layer film is referred to as the upper layer film. Table 18 shows the coating composition and the film thickness of the coated plated steel material.

(2.1.4. Evaluation test)
A test piece of 70 mm × 150 mm size was cut out from the coated plated steel material obtained in (2.1.3) above, appearance evaluation, processed portion corrosion resistance evaluation by exposure test, and plane scratched portion corrosion resistance by exposure test (Tables 29 to 37). Corrosion resistance in scratches), organic film adhesion at the bent part (organic film adhesion in Tables 29 to 37), and organic film adhesion at the bent part after immersion in warm water (water resistant adhesion in Tables 29 to 37) ) Was evaluated by the following evaluation method and evaluation criteria. The evaluation results are shown in Table 29 to Table 37. In addition, appearance evaluation, corrosion resistance evaluation of processed parts by exposure test, corrosion resistance of scratched parts by exposure test (corrosion resistance of scratches in Table 38), organic film adhesion of bent parts (organic film adhesion in Table 38), immersion in hot water Organic film adhesion at the later bending part (water adhesion in Table 38), end face corrosion resistance evaluation by exposure test, processed part corrosion resistance by salt spray test (SST processing in Table 38), and organic coating adhesion at the bending part (Bend part adhesion in Table 38) was evaluated by the following evaluation method and evaluation criteria. The evaluation results are shown in Table 38.

[Appearance evaluation]
The appearance of the surface of the coated plated steel sheet was observed visually and with an optical microscope in the same manner as the plated surface.

  Based on this observation result, the degree of wrinkles on the painted surface was evaluated according to the following criteria. The results are shown in Table 29 to Table 37 and Table 38. In addition, since the degree of unevenness due to wrinkles, sagging, dross adhesion and spangle size on the coating surface recognized in this observation result reflects the underlying plating surface, this observation result was equivalent to the plating surface observation result.

The scores in Tables 29 to 37 and Table 38 are as follows. In the examples of the present invention, the score was 2 or more.
1: When a wrinkle equivalent to 1 is recognized in the following score.
2: When sacrificing or dross equivalent to 1 is observed according to the following score.
3: When neither of the above 1 or 2 applies.
The wrinkles on the painted surface (the surface of the organic coating layer 25) were evaluated according to the following criteria.
5: Wrinkles are not recognized.
4: Wrinkles are slight (wrinkles as shown in FIG. 7A).
3: Wrinkles are small (in the case of evaluation where the level of wrinkles is between 4 and 2).
2: Wrinkle is moderate (better than shown in FIG. 7B).
1: Wrinkles are remarkable (wrinkles as shown in FIG. 7B).

The sagging of the painted surface (the surface of the organic coating layer 25) was evaluated according to the following criteria.
2: Sagging is not recognized.
1: Sagging is observed (sagging as shown in FIG. 9).

Based on the observation result, the dross on the coating surface (the surface of the organic coating layer 25) was evaluated based on the following criteria for the degree of dross attached to the plating layer 23 that can be observed on the surface of the organic coating layer 25. .
2: There is no adhesion of dross with unevenness on the surface of the plating layer 23, or adhesion of dross with unevenness is recognized at less than 5 locations per 1 m ² .
1: The adhesion of dross with unevenness is observed on the surface of the plating layer 23 at 5 or more per 1 m ² .

[Corrosion resistance of processed parts by exposure test]
After extruding 5mm in the center of the test piece with an Erichsen tester (conforming to dimension A of JIS Z 2247), the end face is tape-sealed, and in an environment equivalent to C4 in accordance with ISO 9223, the conditions conforming to JIS D 0205 That is, it was installed so as to face south at an angle of 35 degrees, and the occurrence of rust after 3 years was confirmed and scored as follows.
5: White rust generation area is less than 1%.
4: The area where white rust occurs is 1% or more and less than 5%.
3: White rust generation area is 5% or more and less than 10%.
2: White rust generation area is 10% or more and less than 30%.
1: White rust generation area is 30% or more, or red rust generation is observed.

[Corrosion resistance of flat scratched surface by exposure test]
After an X-shaped scratch reaching the iron core with an NT cutter is made at the center of the test piece, the end face is tape-sealed, and in an environment equivalent to C4 based on ISO 9223, a condition conforming to JIS D 0205, that is, an angle of 35 It was installed so that it would face south, and the rust generation status after 3 years was confirmed.
5: Swelling width of 1/4 or less with respect to the rating 1.
4: Swelling width of 1/3 or less with respect to rating 1.
3: Swelling width of 1/2 or less with respect to the score 1.
2: Swelling width of 2/3 or less with respect to rating 1.
1: Generation of red rust that can be clearly observed from the most remarkable swollen width or front surface.

[Adhesiveness of organic coating at bent part]
In accordance with JIS G 3322, a bending test was conducted with two plates with a thickness of 0.8 mm so that the organic coating would be on the outside, and the cello tape (registered trademark) was applied to the cracks and bends that occurred in the coating. The state of the organic film that had fallen off when the film was peeled off was observed and evaluated according to the following evaluation criteria.
4: Clear cracks are not recognized.
3: Fine cracks were observed.
2: Clear cracking or removal of a small amount of film.
1: Clear film removal.

[Adhesion of organic coating on bent part after immersion in hot water]
After tape-sealing the end face of the test piece and immersing it in ion exchange water at 80 ° C. for 40 hours, in accordance with JIS G 3322, bending 4 pieces of a 0.8 mm thick plate with the organic coating on the outside A bending test was conducted as the inner spacing, and the state of the organic coating that had fallen off when the cellotape (registered trademark) was applied to the crack and the bent portion after peeling was observed and evaluated according to the following evaluation criteria.
4: Clear cracks are not recognized.
3: Fine cracks were observed.
2: Clear cracking or removal of a small amount of film.
1: Clear film removal.

  As shown in Tables 29 to 37, the examples of the present invention are excellent in appearance in two or more points in any evaluation test, processed part corrosion resistance by exposure test, plane scratched part corrosion resistance by exposure test, bending part The organic film adhesion and the organic film adhesion of the bent portion after immersion in warm water were shown. On the other hand, Comparative Example 1 to Comparative Example 4 in which the content of the hot-dip plating layer was out of the scope of the present invention was inferior in corrosion resistance, and Comparative Examples 5 to 10 were inferior in appearance. In Comparative Example 16 and Comparative Example 17, the corrosion resistance of the processed part or the scratched part is inferior because the amount of Mg contained in the hot-dip plated layer is less than 0.1% by mass. Comparative Example 11 without the base treatment film was inferior in the processed part corrosion resistance and the water adhesion of the organic film. In Comparative Example 12, in which the ratio of the organosilicon compound to the organic resin was too low, the scratch corrosion resistance was poor. Comparative Example 13 in which the ratio of the organosilicon compound to the organic resin was excessive was inferior in the processed portion corrosion resistance and water resistance adhesion. Comparative Example 14 in which the thickness of the organic coating was too thin was inferior in processed part corrosion resistance and scratched part corrosion resistance. In Comparative Example 15 in which the thickness of the organic coating was too thick, the organic coating was easily cracked by bending, and the organic coating adhesion was poor.

[End surface corrosion resistance by exposure test]
JIS D in an environment equivalent to C4 based on ISO 9223 standard, with the short side of the test piece cut with a shear cut so that the burrs face downward and the hole around the test piece are anti-corrosive sealed. It was installed so as to face south at an angle of 35 degrees under the conditions of 0205, and the rust expansion width from the end face after three years and the occurrence of red rust were confirmed, and the following ratings were given.
5: Swelling width of 1/4 or less with respect to the rating 1.
4: Swelling width of 1/3 or less with respect to rating 1.
3: Swelling width of 1/2 or less with respect to the score 1.
2: Swelling width of 2/3 or less with respect to rating 1.
1: Generation of red rust that can be clearly observed from the most remarkable swollen width or front surface.

[Corrosion resistance of processed parts by salt spray test]
The test piece was extruded 6 mm by an Erichsen tester (conforming to A dimension of JIS Z 2247) at the center of the test piece, the end face was tape-sealed, and a salt spray test compliant with JIS Z 2371 was conducted. It was performed for 1000 hours, and the rust generation state at each test time of the part subjected to Erichsen processing was observed and evaluated according to the following evaluation criteria.
5: White rust generation area is less than 1%.
4: The area where white rust occurs is 1% or more and less than 5%.
3: White rust generation area is 5% or more and less than 10%.
2: White rust generation area is 10% or more and less than 30%.
1: White rust generation area is 30% or more.

[Adhesiveness of organic coating at bent part]
In accordance with JIS G 3322, a bending test was carried out with 4 sheets of 0.8 mm thick so that the organic coating would be on the outside, and the tape was applied to the cracks and bends that occurred in the coating. The state of the organic film that had fallen off when the film was peeled off was observed and evaluated according to the following evaluation criteria.
4: Clear cracks are not recognized.
3: Fine cracks were observed.
2: Clear cracking or removal of a small amount of film.
1: Clear film removal.

  As shown in Table 38, the Examples of the present invention showed excellent appearance, end surface corrosion resistance, processed part corrosion resistance, and organic coating adhesion in two or more points in any evaluation test.

  As mentioned above, although preferred embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be envisaged within the scope of the claims, and these are naturally within the technical scope of the invention. Is done.

According to the present invention, the corrosion resistance of the scratched part of the painted surface and the processed part in which the underlying steel material is deformed is good, and is resistant to whitening when subjected to heating or when irradiated with ultraviolet rays over a long period of use. Provided is a coated plated steel material that has good rusting properties, and suppresses the generation of wrinkles and sagging on the surface and has a good appearance.

1: Steel material 1a: Steel plate 2: Hot dipping bath 3: Feeder 4: Heating furnace 5: Annealing / cooling section 6: Snout 7: Pot 8: Sink roll 9: Injection nozzle 10: Cooling device 11: Temper rolling / shape Straightening device 12: Winding machine 13: Coil (first coil)
14: Coil (second coil)
15: Conveying roll 16: Feeding machine 17: Winding machine 18: Heating furnace 19: Coil 20: Insulating container 21: Conveying roll 22: Hollow member 23: Aluminum / zinc alloy plating layer (plating layer)
24: Paint base treatment layer 25: Organic coating layer 26: Alloy layer 27: Pre-plating layer 28: Pretreatment layer 29: Coating 101: Primary cooling device 102: Secondary cooling device

Claims (12)

Steel,
A coating on the surface of this steel,
With
The coating has, in order from the steel material, a plating layer, a coating ground treatment layer on the surface of the plating layer, and an organic coating layer on the surface of the coating ground treatment layer,
The plating layer contains Al, Zn, Si, and Mg as constituent elements, and further contains Cr. The Al content is 25 to 75% by mass, the Mg content is 0.1 to 10% by mass, and the Cr content is 0. 0.02 to 1.0 mass%,
The plating layer includes 0.2 to 15% by volume of a Si-Mg phase;
The mass ratio of Mg in the Si—Mg phase to the total amount of Mg in the plating layer is 3% or more and 100% or less,
The coating ground treatment layer contains an organic resin and an organosilicon compound,
The organosilicon compound has an alkylene group, a siloxane bond, and a crosslinkable functional group represented by -SiR ¹ R ² R ³ .
^{Two of} R ¹ , R ² , and R ³ are each an alkoxy group or a hydroxy group;
The remaining one of R ¹ , R ² , and R ³ is an alkoxy group, a hydroxy group, or a methyl group,
The organic silicon compound is 2 to 1500 parts by mass with respect to 100 parts by mass of the organic resin,
A paint-plated steel material, wherein the organic coating layer has a thickness of 0.2 to 100 µm. The Mg content is 0% by mass or more and less than 60% by mass in any region having a diameter of 4 mm and a depth of 50 nm in the outermost layer having a depth of 50 nm from the surface of the plating layer. The paint-plated steel material according to claim 1. The ratio of the Si-Mg phase on the surface of the plating layer is an area ratio of 0% or more and 30% or less, and the coated plated steel material according to claim 1 or 2. The said coating ground-treatment layer contains 1 or more types chosen from a zirconium compound and a titanium compound, The coating plating steel materials of any one of Claims 1-3 characterized by the above-mentioned. 5. The coating plating according to claim 4 , wherein in the coating ground treatment layer, one or more selected from the zirconium compound and the titanium compound is 50 to 3333 parts by mass with respect to 100 parts by mass of the organic resin. Steel material. 5. The coating plating according to claim 4 , wherein one or more selected from the zirconium compound and the titanium compound is 1 to 50 parts by mass with respect to 100 parts by mass of the organic resin in the coating base treatment layer. Steel material. The said coating ground-treatment layer contains 0.5-100 mass parts of silicas further with respect to 100 mass parts of said organic resins, The coating plating steel materials of any one of Claims 1-6 characterized by the above-mentioned. The paint undercoating layer further said to organic resin 100 parts by weight, paint plating steel according to any one of claims 1 to 7, characterized in that it contains a phosphate compound 0.5 to 40 parts by weight . The said coating ground-treatment layer contains tannin, tannic acid, or 1-50 mass parts of tannic acid salts with respect to 100 mass parts of said organic resins further, The any one of Claims 1-8 characterized by the above-mentioned. Painted steel as described in 1. The paint undercoating layer further with respect to the organic resin 100 parts by weight paint according to any one of claims 1 to 9, characterized in that it contains 0.5 to 10 parts by etching property fluoride Plated steel. The said organic coating layer consists of two layers, the lower layer containing a rust preventive pigment, and the colored upper layer, The coating plating steel materials of any one of Claims 1-10 characterized by the above-mentioned. Paint plating steel according to any one of claims 1 to 11, the amount of deposition of the paint undercoating layer is characterized by a 10~2000mg / ^{m 2.}