TWI836516B - Zn-Al-Mg-BASED COATED CHECKERED SHEET - Google Patents

Abstract

A Zn-Al-Mg coated textured steel plate has a convex portion and a flat portion on the plate surface, and the coating layer of the steel plate has a predetermined chemical composition; at the center of the long side direction of the convex portion, a cut surface is observed that is perpendicular to the long side direction of the convex portion and is cut along the plate thickness direction. At this time, the coating layer thickness ratio of the flat portions on the left and right sides of the convex portion (the coating layer thickness on the left side/the coating layer thickness on the right side) is The thickness of the layer is greater than 0.2 and less than 5.0; and the mesh height T-t and the gap height x satisfy the following equations 1 and 2; the mesh height T-t is: the mesh height when the thickness of the base mesh steel plate in the convex part is T and the thickness of the base mesh steel plate in the flat part is t; the gap height x is: the gap height between the coated mesh steel plate and the static surface when the coated mesh steel plate is static.

Formula 1: x/(T-t)≦1.5

Formula 2: 0.5<T-t≦t

Description

Zn-Al-Mg based plated reticulated steel plate

The present disclosure relates to a Zn-Al-Mg based plated corrugated steel plate.

Corrugated steel is a type of steel plate with continuous anti-skid convex parts (i.e. protrusions) added to the surface by rolling. Generally speaking, the convex parts with fixed width, fixed length and fixed height are set at a fixed angle and fixed interval in the rolling direction. Corrugated steel plates are usually manufactured by hot rolling. In addition, corrugated steel plates are used for the bottom plates or steps of large vehicles (buses, trucks, etc.), paving plates of parking lots, paving plates of factories, ship decks, temporary scaffolding or stairs at construction sites, etc.

For example, Patent Document 1 discloses: "A hot-dip galvanized corrugated steel plate, which has a base steel plate, a Ni plating layer disposed on the surface of the base steel plate, and a hot plating layer disposed on the surface of the Ni plating layer, and The plate surface has a convex part and a flat part; and the film thickness of the Ni plating layer before the convex part is 0.07~0.4 μm per side, and the film thickness of the Ni plating layer before the flat part is 0.05~0.05 μm per side. 0.35 μm , the film thickness of the Ni plating layer in front of the convex portion is greater than 100% and 400% or less relative to the film thickness of the Ni plating layer in the flat portion, and the adhesion amount of the molten plating layer is per Surface 60~400g/m ² , and the chemical composition of the aforementioned molten plating layer includes in mass %: Al: greater than 1.0% and less than 26%, Mg: 0.05~10%, Si: 0~1.0%, Sn: 0 ~3.0% and Ca: 0~1.0%, and the remainder is composed of Zn and impurities."

Furthermore, Patent Document 2 discloses: "A method for continuous molten metal plating of a strip-shaped mesh steel plate, wherein the strip-shaped mesh steel plate is pickled and then continuously molten metal plating is performed under the following conditions: annealing temperature: 450~850℃, steel strip tension in the annealing furnace: 0.3~2.0kg/ ^mm2 , steel strip tension in the plating production line: 0.3~3.0kg/ ^mm2 , molten metal wiping gas pressure: 0.02~1.5kg/ ^cm2 ."

Prior technical literature

patent documents

Patent document 1: International Gazette No. 2019/054483

Patent Document 2: Japanese Patent No. 2743774

Corrugated steel plates are mostly used outdoors, so corrosion resistance is required. Therefore, as disclosed in Patent Documents 1 to 2, hot-dip plating is performed on the corrugated steel plate to improve the corrosion resistance.

On the other hand, textured steel plates are used for scaffolding, anti-skid, etc., so flatness is also required.

However, the corrugated steel plate is a steel plate that has local plate thickness differences through convex portions and flat portions. Therefore, if the corrugated steel plate is hot-plated in order to improve the corrosion resistance, the amount of expansion and shrinkage caused by the temperature change will be different between the convex portion and the flat portion of the corrugated steel plate, and the corrugated steel plate will Deformation. If the deformed plated mesh steel plate is made into products, the flatness will become worse. In addition, once the flatness deteriorates, the thickness of the plating layer will vary, and the corrosion resistance and processability will decrease.

In particular, compared with Zn-based plating baths, the viscosity of Zn-Al-Mg alloy plating baths is lower. Therefore, if the flatness of the textured steel plate deteriorates, the thickness of the coating layer will easily vary, and the corrosion resistance and processability will be reduced. Therefore, there is a demand for further improvement in the flatness of Zn-Al-Mg-based coated textured steel plates.

Therefore, the subject of this disclosure is to provide a Zn-Al-Mg based plated textured steel plate excellent in flatness, corrosion resistance and workability.

The above problems can be solved in the following ways.

<1> A Zn-Al-Mg plated corrugated steel plate, which has a base corrugated steel plate and a plating layer. The base corrugated steel plate is provided with a convex part and a flat part on one of the plate surfaces, and the plating layer It is disposed on the plate surface provided with convex portions and flat portions of the aforementioned base corrugated steel plate, and the coating layer includes a Zn-Al-Mg alloy layer; the aforementioned coating layer has a chemical composition consisting of the following: in mass % In total, Zn: greater than 65.0%, Al: greater than 1.0% and less than 25.0%, Mg: greater than 1.0% and less than 12.5%, Sn: 0%~5.0%, Bi: 0%~less than 5.0%, In: 0%~ Less than 2.0%, Ca: 0%~3.00%, Y: 0%~0.5%, La: 0%~less than 0.5%, Ce: 0%~less than 0.5%, Si: 0%~less than 2.5%, Cr: 0 %~less than 0.25%, Ti: 0%~less than 0.25%, Zr: 0%~less than 0.25%, Mo: 0%~less than 0.25%, W: 0%~less than 0.25%, Ag: 0%~less than 0.25% ,P: 0%~less than 0.25%, Ni: 0%~less than 0.25%, Co: 0%~less than 0.25%, V: 0%~less than 0.25%, Nb: 0%~less than 0.25%, Cu: 0%~less than 0.25%, Mn: 0%~ Less than 0.25%, Li: 0%~less than 0.25%, Na: 0%~less than 0.25%, K: 0%~less than 0.25%, Fe: 0%~5.0%, Sr: 0%~less than 0.5%, Sb: 0%~less than 0.5%, Pb: 0%~less than 0.5%, B: 0%~less than 0.5% and impurities; at the center of the long side direction of the aforementioned convex part, when observed, it is orthogonal to the long side direction of the aforementioned convex part and On the cutting surface obtained by cutting along the plate thickness direction, at this time, the thickness ratio of the plating layer (thickness of the plating layer on the left side/thickness of the plating layer on the right side) of the flat portions on the left and right sides of the convex portion is 0.2 or more. And less than 5.0; and the texture height T-t and the gap height The height of the texture when the thickness of the aforementioned base textured steel plate is t; the gap height The height of the board gap.

Formula 1: x/(T-t)≦1.5

Formula 2: 0.5<T-t≦t

The units of the base mesh steel plate thickness T, t, and gap height x in Formula 1 and Formula 2 are "mm".

<2> The Zn-Al-Mg coated mesh steel plate as in <1>, wherein the Al concentration is greater than 5.0% and less than 25.0%, and the Mg concentration is greater than 3.0% and less than 12.5%.

<3> A Zn-Al-Mg coated mesh steel plate as in <1> or <2>, wherein the coating layer comprises an Al-Fe alloy layer between the base mesh steel plate and the Zn-Al-Mg alloy layer.

According to the present disclosure, it is possible to provide a Zn-Al-Mg-based plated mesh steel plate excellent in flatness, corrosion resistance, and workability.

B’: Base mesh steel plate

C’: Plating layer

Q: convex part

P: flat part

T: Thickness of the base mesh steel plate in the convex part

t: Thickness of base corrugated steel plate in the flat part

x: Gap height

CS: Sample of plated corrugated steel plate

EG: The boundary between the convex part and the flat part

FP: 3mm away from the boundary between the convex part and the flat part

FT: Thickness of the coating layer on the flat part

Su:Stationary surface

A: Arrangement angle of the convex part relative to the rolling direction (Figure 3A~Figure 3C)

B: The length of one convex part (Figure 3A~Figure 3C)

C: The maximum width of one convex part (Figure 3A~Figure 3C)

D: Minimum width of one convex part (Figure 3A~Figure 3C)

E: Arrangement spacing of convex parts (Figure 3A~Figure 3C)

H: Height of convex part (Figure 3A~Figure 3C)

Figure 1A is a SEM photograph (500 times) showing an example of a cross-section of the Zn-Al-Mg based plated mesh steel plate of the present disclosure.

Figure 1B is an SEM photograph (2000 times) showing an example of the cross-section of the Zn-Al-Mg based plated corrugated steel plate of the present disclosure.

Figure 2 is a schematic diagram illustrating the method for measuring the gap height x in the Zn-Al-Mg based plated mesh steel plate of the present disclosure.

3A is a schematic top view showing an example of the base corrugated steel plate of the Zn-Al-Mg based plated corrugated steel plate of the present disclosure.

FIG. 3B is a schematic cross-sectional view showing an example of the base corrugated steel plate of the Zn-Al-Mg based plated corrugated steel plate of the present disclosure, and is a G-G cross-sectional schematic view of FIG. 3A .

FIG. 3C is a schematic cross-sectional view showing an example of the base corrugated steel plate of the Zn-Al-Mg based plated corrugated steel plate of the present disclosure, and is a schematic cross-sectional view taken along line F-F of FIG. 3A .

Form used to implement the invention

An example of this disclosure will be described below.

In addition, in this disclosure, the "%" symbol for the content of each element in the chemical composition means "mass %".

The numerical range represented by "~" means the range including the values recorded before and after "~" as the lower limit and upper limit.

The numerical range when the numerical value written before and after "~" is appended with "greater than" or "less than" means a range that does not include these numerical values as the lower limit or upper limit.

The element content of a chemical composition is sometimes labeled as element concentration (such as Zn concentration, Mg concentration, etc.).

The Zn-Al-Mg based plated textured steel plate (hereinafter also referred to as "plated textured steel plate") disclosed in the present disclosure is a plated textured steel plate, which has a base textured steel plate and a plating layer. The base textured steel plate If one of the plate surfaces is provided with convex portions and flat portions, the plating layer is disposed on the plate surface of the aforementioned base corrugated steel plate that is provided with convex portions and flat portions, and the plating layer contains Zn-Al-Mg alloy layer.

Moreover, in the plated mesh steel plate of the present disclosure, the plating layer has a predetermined chemical composition; at the central portion of the longitudinal direction of the aforementioned convex portion, the result obtained by observing is orthogonal to the longitudinal direction of the convex portion and cut along the thickness direction of the plate. On the cut surface, at this time, the thickness ratio of the plating layer (thickness of the plating layer on the left side/thickness of the plating layer on the right side) of the flat portions on the left and right sides of the convex portion is 0.2 or more and 5.0 or less; and the texture height T-t and the gap height The height of the pattern; the gap height

Formula 1: x/(T-t)≦1.5

Formula 2: 0.5<T-t≦t

The unit of thickness T, t, and gap height x of the base corrugated steel plate in Formula 1 and Formula 2 is "mm".

The plated corrugated steel plate of the present disclosure is a Zn-Al-Mg based plated corrugated steel plate with excellent flatness, corrosion resistance and processability through the above-mentioned structure. Furthermore, the plated corrugated steel plate of the present disclosure was discovered based on the following knowledge and insights.

The inventors studied how to further improve the flatness even in a Zn-based plating bath with a higher viscosity. Even in low Zn-Al-Mg plating, the variation in the thickness of the plating layer can still be suppressed. As a result, the following knowledge and insights were obtained.

The deterioration of the flatness of the plated corrugated steel plate will not only affect the heating temperature of the base corrugated steel plate before immersion in the plating bath, but also affect the heating rate and cooling rate. Specifically, if the base corrugated steel plate is hot-plated, the amount of expansion and contraction caused by the rapid temperature change in the convex portions and flat portions with different plate thicknesses due to rapid heating and cooling before immersion in the plating bath. Differences will also occur and thus deformation will occur. The reason for this is that unlike ordinary flat steel plates, differences in heating and cooling rates occur between the convex portions and the flat portions of the base corrugated steel plate during heating and cooling.

Therefore, if the base mesh steel plate is heated and cooled before the dip plating bath at a gentle heating and cooling rate, the difference in heating and cooling rates will not easily occur in the convex and flat parts with different plate thicknesses. In this way, the convex and flat parts will be heated and cooled as evenly as possible, and deformation can be suppressed. As a result, the flatness of the base mesh steel plate will be further improved, and the thickness variation of the coating layer will be reduced in the Zn-Al-Mg coating, and the corrosion resistance and processability will be improved.

That is, the inventors have learned that a Zn-Al-Mg coated mesh steel plate can be obtained, which satisfies the above-mentioned coating layer thickness ratio of the flat portion, the above-mentioned formula 1 and the above-mentioned formula 2.

From the above knowledge and understanding, it can be found that the coated mesh steel plate disclosed in this invention will become a Zn-Al-Mg coated mesh steel plate with excellent flatness, corrosion resistance and processability.

The following is a description of the details of the coated textured steel plate disclosed herein.

(Base mesh steel plate)

The base mesh steel plate is the target steel plate for plating. One of the plate surfaces of the base mesh steel plate is provided with a convex portion and a flat portion.

The base mesh steel plate is usually given a convex shape by hot rolling. The type of steel of the base mesh steel plate is not particularly limited. The base mesh steel plate can be, for example, a type of steel equivalent to general structural rolled steel specified in JIS G3101:2015.

The convex shape of the base textured steel plate is imparted by, for example, transferring the concave shape formed in the actuating roll to the steel plate surface during the finishing stage of hot rolling.

In addition, the opposite plate surface facing the plate surface with the convex portion and the flat portion in the plate thickness direction is a surface having the surface characteristics of a normal steel plate. Specifically, the opposite plate surface facing the plate surface with the convex portion and the flat portion in the plate thickness direction is a plate surface given by, for example, using a normal rolling roller (i.e., a roller with a normal roughness) in the finishing hot rolling stage, and the rolling roller is opposite to the actuating roller on which the convex portion and the flat portion can be provided.

The base corrugated steel plate can also be a pre-plated pre-plated corrugated steel plate. Pre-plated textured steel sheets are obtained by, for example, electrolytic treatment methods or alternative plating methods. In the electrolytic treatment method, the base corrugated steel plate is immersed in a sulfuric acid bath or a chloride bath containing metal ions of various pre-plating components for electrolysis treatment, thereby obtaining the pre-plated corrugated steel plate. In the substitution plating method, the base textured steel plate is immersed in an aqueous solution containing various pre-plating component metal ions and the pH is adjusted with sulfuric acid, so that the metal is substituted and precipitated to obtain the pre-plated textured steel plate.

As a preplated textured steel plate, a Ni preplated textured steel plate can be cited as a representative example.

(plated layer)

The plating layer contains a Zn-Al-Mg alloy layer. In addition to the Zn-Al-Mg alloy layer, the plating layer may also include an Al-Fe alloy layer. The Al-Fe alloy layer is arranged between the base corrugated steel plate and the Zn-Al-Mg alloy layer.

That is, the plating layer may have a single-layer structure of a Zn-Al-Mg alloy layer, or may have a laminated structure including a Zn-Al-Mg alloy layer and an Al-Fe alloy layer. In the case of a laminated structure, it is preferable that the Zn-Al-Mg alloy layer constitutes the surface of the plating layer.

However, an oxide film of the elements constituting the coating layer is formed on the surface of the coating layer with a thickness of about 50nm, but the thickness of the oxide film is relatively thin compared to the thickness of the entire coating layer and is considered not to constitute the main body of the coating layer.

The adhesion amount of the plating layer should be 60~500g/m ² per side.

If the adhesion amount of the plating layer is 60g/m ² or more, corrosion resistance can be ensured more reliably. On the other hand, if the adhesion amount of the plating layer is 500 g/m ² or less, appearance defects such as sagging of the plating layer can be suppressed.

Next, the chemical composition of the plating layer will be described.

The chemical composition of the coating layer is set to be composed of the following chemical composition: in terms of mass%, Zn: greater than 65.0%, Al: greater than 1.0% and less than 25.0%, Mg: greater than 1.0% and less than 12.5%, Sn: 0%~5.0%, Bi: 0%~less than 5.0%, In: 0%~less than 2.0%, Ca: 0%~3.00%, Y: 0%~0.5%, La: 0%~less than 0.5%, Ce: 0%~less than 0.5%, Si: 0%~less than 2.5%, Cr: 0%~less than 0.25%, Ti: 0%~less than 0.25%, Zr: 0%~less than 0.25%, Mo: 0%~less than 0.25%, W: 0%~less than 0.25%, Ag: 0%~less than 0.25%, P: 0%~less than 0.25%, Ni: 0%~less than 0.25%, Co: 0%~less than 0.25%, V: 0%~less than 0.25%, Nb: 0%~less than 0.25%, Cu: 0%~less than 0.25%, Mn: 0%~less than 0.25%, Li: 0%~less than 0.25%, Na: 0%~less than 0.25%, K: 0%~less than 0.25%, Fe: 0%~5.0%, Sr: 0%~less than 0.5%, Sb: 0%~less than 0.5%, Pb: 0%~less than 0.5%, B: 0%~less than 0.5% and impurities.

In the chemical composition of the plating layer, Sn, Bi, In, Ca, Y, La, Ce, Si, Cr, Ti, Zr, Mo, W, Ag, P, Ni, Co, V, Nb, Cu, Mn, Li, Na, K, Fe, Sr, Sb, Pb and B are optional components. That is, the plating layer does not need to contain these elements. When these optional components are included, the content of each optional element is preferably within the range described below.

Here, the chemical composition of the coating layer is the average chemical composition of the entire coating layer (when the coating layer is a single-layer structure of Zn-Al-Mg alloy layer, it is the average chemical composition of the Zn-Al-Mg alloy layer ; When the plating layer has a laminated structure of an Al-Fe alloy layer and a Zn-Al-Mg alloy layer, it is the average chemical composition of the total of the Al-Fe alloy layer and the Zn-Al-Mg alloy layer).

Generally speaking, in the melt plating method, since the formation reaction of the plating layer is almost completed in the plating bath, the chemical composition of the Zn-Al-Mg alloy layer is roughly the same as the chemical composition of the plating bath. In addition, in the melt plating method, the Al-Fe alloy layer will be formed and grown immediately after being immersed in the plating bath. Moreover, the Al-Fe alloy layer will mostly complete the formation reaction in the plating bath, and its thickness is also small enough compared to the Zn-Al-Mg alloy layer.

Therefore, as long as no special heat treatment such as heating alloying treatment is performed after plating, the average chemical composition of the entire plating layer is substantially equivalent to the chemical composition of the Zn-Al-Mg alloy layer, and the composition of the Al-Fe alloy layer can be ignored.

Below, the elements of the coating are explained.

Zn: greater than 65.0%

Zn is an essential element for obtaining corrosion resistance. When the Zn concentration is considered in terms of atomic composition ratio, since the coating layer is composed of low specific gravity elements such as Al and Mg, the atomic composition ratio must still be dominated by Zn.

Therefore, the Zn concentration is set to be greater than 65.0%. The Zn concentration should be above 70%. In addition, the upper limit of the Zn concentration is the concentration of the remaining elements other than Zn and impurities.

Al: greater than 1.0% and less than 25.0%

Al is an essential element to form Al crystals and ensure corrosion resistance. Furthermore, Al is also an essential element for improving the adhesion of the plating layer and ensuring workability. Therefore, the lower limit of the Al concentration is set to be greater than 1.0% (preferably greater than 5.0%, preferably more than 10.0%).

On the other hand, if the Al concentration increases excessively, the corrosion resistance tends to deteriorate. Therefore, the upper limit of the Al concentration is set to less than 25.0% (preferably less than 23.0%).

Mg: greater than 1.0% and less than 12.5%

Mg is an essential element to ensure corrosion resistance. Therefore, the lower limit of Mg concentration is set to be greater than 1.0% (preferably greater than 3.0%, and more preferably greater than 5.0%).

On the other hand, if the Mg concentration increases excessively, workability tends to deteriorate. Therefore, the upper limit of Mg concentration is less than 12.5% (preferably less than 10.0%).

Sn: 0~5.0%

Sn is an element that contributes to corrosion resistance. Therefore, the lower limit of Sn concentration should be greater than 0% (preferably 0.1% or more, preferably 0.5% or more).

On the other hand, if the Sn concentration is excessively increased, corrosion resistance tends to deteriorate. Therefore, the upper limit of Sn concentration is set to 5.0% or less (preferably 3.0% or less).

Bi: 0%~less than 5.0%

A series of elements that contribute to corrosion resistance. Therefore, the lower limit of Bi concentration should be greater than 0% (preferably more than 0.1%, preferably more than 3.0%).

On the other hand, if the Bi concentration is excessively increased, corrosion resistance tends to deteriorate. Therefore, the upper limit of Bi concentration is set to less than 5.0% (preferably less than 4.8%).

In: 0%~less than 2.0%

In is an element that contributes to corrosion resistance. Therefore, the lower limit of In concentration should be greater than 0% (preferably 0.1% or more, preferably 1.0% or more).

On the other hand, if the In concentration is excessively increased, corrosion resistance tends to deteriorate. Therefore, the upper limit of In concentration is set to less than 2.0% (preferably less than 1.8%).

Ca: 0%~3.0%

Ca is an element that can adjust the amount of Mg dissolution that is most suitable for imparting corrosion resistance. Therefore, the lower limit of Ca concentration should be greater than 0% (preferably above 0.05%).

On the other hand, if the Ca concentration is excessively increased, corrosion resistance and workability tend to deteriorate. Therefore, the upper limit of the Ca concentration is set to 3.0% or less (preferably 1.0% or less).

Y：0%~0.5%

Y series elements contribute to corrosion resistance. Therefore, the lower limit of Y concentration should be greater than 0% (preferably above 0.1%).

On the other hand, if the Y concentration is excessively increased, the corrosion resistance tends to deteriorate. Therefore, the upper limit of the Y concentration is set to 0.5% or less (preferably 0.3% or less).

La and Ce: 0%~less than 0.5%

La and Ce are elements that contribute to corrosion resistance. Therefore, the lower limits of La concentration and Ce concentration should each be larger. at 0% (preferably above 0.1%).

On the other hand, if the La concentration and Ce concentration increase excessively, the corrosion resistance tends to deteriorate. Therefore, the upper limit of the La concentration and Ce concentration is set to be less than 0.5% (preferably less than 0.4%).

Si: 0%~less than 2.5%

Si is an element that inhibits the growth of the Al-Fe alloy layer and helps improve corrosion resistance. Therefore, the Si concentration should be greater than 0% (preferably more than 0.05%, preferably more than 0.1%). Especially when Sn is not included (that is, when the Sn concentration is 0%), from the viewpoint of ensuring corrosion resistance, the Si concentration is preferably 0.1% or more (preferably 0.2% or more).

On the other hand, if the Si concentration increases excessively, the corrosion resistance and processability tend to deteriorate. Therefore, the upper limit of the Si concentration is set to less than 2.5%. In particular, from the perspective of corrosion resistance, the Si concentration should be less than 2.4%, preferably less than 1.8%, and more preferably less than 1.2%.

Cr, Ti, Zr, Mo, W, Ag, P, Ni, Co, V, Nb, Cu, Mn, Li, Na and K: 0%~less than 0.25%

Cr, Ti, Zr, Mo, W, Ag, P, Ni, Co, V, Nb, Cu, Mn, Li, Na and K are elements that contribute to corrosion resistance. Therefore, the lower limits of the concentrations of Cr, Ti, Zr, Mo, W, Ag, P, Ni, Co, V, Nb, Cu, Mn, Li, Na and K should each be greater than 0% (preferably more than 0.05% , preferably more than 0.1%).

On the other hand, if the concentrations of Cr, Ti, Zr, Mo, W, Ag, P, Ni, Co, V, Nb, Cu, Mn, Li, Na and K are excessively increased, corrosion resistance will tend to deteriorate. Therefore, the upper limit values of the concentrations of Cr, Ti, Zr, Mo, W, Ag, P, Ni, Co, V, Nb, Cu, Mn, Li, Na and K are each set to less than 0.25%. The upper limit of the concentration of Cr, Ti, Zr, Mo, W, Ag, P, Ni, Co, V, Nb, Cu, Mn, Li, Na and K is preferably 0.22% or less.

Fe: 0%~5.0%

When the coating is formed by melt coating, the Zn-Al-Mg alloy layer and the Al-Fe alloy layer contain a fixed Fe concentration.

It has been confirmed that the Fe concentration of up to 5.0% in the coating layer (especially the Zn-Al-Mg alloy layer) will not have any adverse effect on performance. Most of the Fe is contained in the Al-Fe alloy layer, so if the thickness of this layer is large, the Fe concentration will generally increase.

Sr, Sb, Pb and B: 0%~less than 0.5%

Sr, Sb, Pb and B are elements that contribute to corrosion resistance. Therefore, the lower limit of the concentration of Sr, Sb, Pb and B should be greater than 0% (preferably 0.05% or more, preferably 0.1% or more).

On the other hand, if the concentrations of Sr, Sb, Pb and B are excessively increased, corrosion resistance tends to deteriorate. Therefore, the upper limit values of the concentrations of Sr, Sb, Pb and B are each set to less than 0.5%.

Impure things

Impurities refer to components contained in the raw materials or components mixed in during the manufacturing process, rather than components that are intentionally included. For example, in the plating layer, sometimes trace amounts of components other than Fe are mixed in as impurities due to mutual atomic diffusion between the base textured steel plate and the plating bath.

The chemical composition of the coating is determined by the following method.

First, an acid solution is obtained after the plated layer is stripped and dissolved by an acid, and the acid contains an inhibitor that inhibits the corrosion of the base textured steel plate. Then, the obtained acid solution is measured by ICP analysis to obtain the chemical composition of the plated layer (when the plated layer is a single layer structure of a Zn-Al-Mg alloy layer, it is the chemical composition of the Zn-Al-Mg alloy layer; when the plated layer is a multilayer structure of an Al-Fe alloy layer and a Zn-Al-Mg alloy layer, it is the combined chemical composition of the Al-Fe alloy layer and the Zn-Al-Mg alloy layer). There is no particular limitation on the type of acid as long as it is an acid that can dissolve the plated layer. In addition, the chemical composition is measured as an average chemical composition. In addition, in ICP analysis, Zn concentration is calculated using "Formula (a): Zn concentration = 100% - other element concentrations (%)".

Here, when a pre-plated textured steel plate is used as the base textured steel plate, the components of the pre-plating are also detected.

For example, when a Ni pre-plated textured steel plate is used, not only the Ni in the plating layer but also the Ni in the Ni pre-plating will be detected in the ICP analysis. Specifically, when a pre-plated textured steel plate with a Ni adhesion amount of 1g/m ² ~3g/m ² (thickness approximately 0.1~0.3μm) is used as the base textured steel plate, even if the Ni contained in the plating layer If the concentration is 0%, the Ni concentration will still be detected at 0.1~15%. Therefore, the Ni concentration in the plating layer may not be clear from the results of ICP analysis. Therefore, when a Ni preplated textured steel sheet is used as the base steel sheet, the Ni concentration in the plating layer is measured by a glow discharge luminescence analysis method (quantitative GDS). Specifically, three or more types of standard samples with different Ni concentrations were used in a high-frequency glow discharge luminescence surface analysis device (manufactured by Horiba Manufacturing Co., Ltd., model: GD-Profiler2) to create a measurement based on the relationship between Ni concentration and Ni luminescence intensity. curve. The standard samples use Zn alloy standard samples IMN ZH1, ZH2, and ZH4 made by BAS. The measurement conditions of GDS are set as follows.

H.V.: Fe is 785V, Ni is 630V, Co is 720V

Anode diameter: φ4mm

Gas: Ar

Gas pressure: 600Pa

Output: 35W

Next, GDS is used under the above conditions to calculate the Ni luminescence intensity at the 1/2 film thickness position of the coated steel material to be measured. Then, the Ni concentration at the 1/2 position of the coated layer is calculated from the obtained Ni luminescence intensity and the prepared calibration curve. The so-called 1/2 position of the coated layer is the position at 1/2 of the time when the Fe intensity reaches saturation, that is, the time when it reaches the base iron in the GDS analysis under the above conditions. The Ni concentration at the 1/2 position of the coated layer is regarded as the Ni concentration in the coated layer. At this time, the "concentration of other elements (%)" in the above formula (1) for calculating the Zn concentration is the sum of the concentration (%) of elements other than Ni in the ICP analysis and the Ni concentration (%) in the GDS analysis. That is, when the Ni pre-plated steel is used as the base steel, the Zn concentration of the coating layer is calculated by "Formula (a'): Zn concentration = 100-(concentration (%) of elements other than Ni in the ICP analysis + Ni concentration (%) in the GDS analysis)". In addition, when the Ni pre-plated mesh steel plate is used as the base mesh steel plate, when the base mesh steel plate is immersed in the plating bath, a small amount of Ni in the Ni pre-plated layer will dissolve into the plating bath. Therefore, the Ni concentration in the plating bath will increase by 0.02~0.03% compared to the Ni concentration in the plating bath after the bath. Therefore, when Ni pre-plated textured steel sheets are used, the Ni concentration in the plating layer will increase by a maximum of 0.03%.

Here, the method to determine whether the base textured steel plate is a pre-plated textured steel plate is as follows.

A sample is taken from the target corrugated steel plate, and the cross section of the sample cut along the thickness direction of the corrugated steel plate is the measurement surface.

For the measurement surface of the sample, the Ni concentration is measured by line analysis near the interface between the coating layer in the mesh steel plate and the base mesh steel plate using an Electron Probe MicroAnalyser (FE-EPMA). The measurement conditions are: accelerating voltage 15kV, beam diameter of about 100nm, irradiation time of 1000ms per point, and measurement distance 60nm. In addition, the measurement distance can be a distance that can confirm whether the Ni concentration is concentrated at the interface between the coating layer in the mesh steel plate and the base mesh steel plate.

Furthermore, if the Ni concentration in the interface between the coating layer and the base textured steel plate in the textured steel plate becomes high, the base textured steel plate is judged to be a pre-plated textured steel plate.

Next, the Al-Fe alloy layer will be described.

An Al-Fe alloy layer is sometimes formed on the surface of the base mesh steel plate (specifically, between the base mesh steel plate and the Zn-Al-Mg alloy layer), and in terms of structure, it is a layer with Al ₅ Fe phase as the main phase. The Al-Fe alloy layer is formed by atomic diffusion between the base mesh steel plate and the plating bath. Since the mesh steel plate disclosed in the present invention forms the plating layer by melt plating, the Al-Fe alloy layer is easily formed in the plating layer containing the Al element. Moreover, since the plating bath contains Al above a fixed concentration, the Al ₅ Fe phase will be formed the most. However, atomic diffusion takes time, and there will be a portion with an increased Fe concentration near the base mesh steel plate. Therefore, the Al-Fe alloy layer sometimes contains a small amount of AlFe phase, Al ₃ Fe phase, Al ₅ Fe ₂ phase, etc. In addition, since the plating bath also contains a fixed concentration of Zn, the Al-Fe alloy layer also contains a small amount of Zn.

Regarding the corrosion resistance of Al ₅ Fe phase, Al ₃ Fe phase, AlFe phase and Al ₅ Fe ₂ phase, no matter which phase it is, there is little difference. The corrosion resistance here refers to the corrosion resistance of the part not affected by welding.

Here, when the plating layer contains Si, Si is especially easily incorporated into the Al-Fe alloy layer. Sometimes an Al-Fe-Si intermetallic compound phase forms. As an identifiable intermetallic compound phase, there is the AlFeSi phase, and as isomers, there are α, β, q1, q2-AlFeSi phases, etc. Therefore, in the Al-Fe alloy layer, the AlFeSi may be detected as equal. The Al-Fe alloy layer containing the AlFeSi equivalent is also called an Al-Fe-Si alloy layer.

In addition, compared with the Zn-Al-Mg alloy layer, the thickness of the Al-Fe-Si alloy layer is also smaller, so it has less impact on the corrosion resistance of the entire plating layer.

Furthermore, when various pre-plated textured steel sheets are used as the base textured steel sheet, the structure of the Al-Fe alloy layer may change due to the amount of pre-plating. Specifically, there are the following situations: a pure metal layer used for pre-plating remains around the Al-Fe alloy layer; an intermetallic compound phase (such as Al ₃ Ni phase) formed by the components of the Zn-Al-Mg alloy layer and the pre-plating components forms an alloy layer; an Al-Fe alloy layer is formed in which a part of Al atoms and Fe atoms are substituted; or an Al-Fe-Si alloy layer is formed in which a part of Al atoms, Fe atoms and Si atoms are substituted.

That is, the so-called Al-Fe alloy layer is a layer that includes alloy layers of various aspects described above in addition to the alloy layer mainly composed of the Al ₅ Fe phase.

In addition, among various pre-plated corrugated steel sheets, when a plating layer is formed on the Ni pre-plated corrugated steel sheet, an Al-Ni-Fe alloy layer is formed as an Al-Fe alloy layer.

The thickness of the Al-Fe alloy layer is, for example, greater than 0 μm and less than 7 μm.

From the viewpoint of improving the adhesion of the plating layer (specifically, the Zn-Al-Mg alloy layer) and ensuring corrosion resistance and workability, the thickness of the Al-Fe alloy layer is preferably 0.05 μm or more and 5 μm or less.

The thickness of the Zn-Al-Mg alloy layer is usually thicker than that of the Al-Fe alloy layer. Therefore, compared with the Zn-Al-Mg alloy layer, the Al-Fe alloy layer is more suitable for plating. The corrosion resistance of corrugated steel plate is relatively low. However, as inferred from the composition analysis results, the Al-Fe alloy layer contains corrosion-resistant elements Al and Zn at a fixed concentration or above. Therefore, the Al-Fe alloy layer has a certain degree of corrosion resistance against the base corrugated steel plate.

Furthermore, if a plating layer with a chemical composition specified in this disclosure is formed by a hot-dip plating method, an Al-Fe alloy layer of 100 nm or more will probably be formed between the base corrugated steel plate and the Zn-Al-Mg alloy layer. .

From the perspective of corrosion resistance, the thicker the Al-Fe alloy layer, the better. Therefore, the thickness of the Al-Fe alloy layer should be 0.05μm or more. However, a thick Al-Fe alloy layer will cause a significant deterioration in the plating processability, so it is better to be below a fixed thickness. From the perspective of processability, the thickness of the Al-Fe alloy layer should be 7μm or less. If the thickness of the Al-Fe alloy layer is 7μm or less, the amount of cracks and powdering generated from the Al-Fe alloy layer will be reduced, and the processability will be improved. The thickness of the Al-Fe alloy layer is more preferably 5μm or less, and more preferably 2μm or less.

The thickness of the Al-Fe alloy layer is measured as follows.

After the sample is buried in the resin and polished, the thickness of the Al-Fe alloy layer is measured at any five locations in the SEM reflection electron image of the cross section of the coating layer (the cut surface along the thickness direction of the coating layer) (however, the Al-Fe alloy layer can be visually identified at a magnification of 10,000 times and a field size of 50μm in length × 200μm in width). Then, the arithmetic average of the five locations is regarded as the thickness of the Al-Fe alloy layer.

(Characteristics of coated textured steel plate)

-Thickness ratio of the coating layer on the flat part-

In the coated mesh steel plate disclosed in the present invention, when thinner and thicker coating layers are locally generated in the flat portion, the corrosion resistance will deteriorate. In addition, the workability will also deteriorate.

Therefore, the thickness ratio of the coating layer on the flat parts on the left and right of the protrusion (thickness of the coating layer on the left side/thickness of the coating layer on the right side) is set to be greater than 0.2 and less than 5.0.

From the perspective of improving corrosion resistance and processability, the thickness ratio of the coating layer on the flat portion (thickness of the coating layer on the left side/thickness of the coating layer on the right side) should be greater than 0.25 and less than 4.00, and more preferably greater than 0.33 and less than 3.00.

Here, from the viewpoint of corrosion resistance and workability, the thickness of the plating layer on the flat portion is preferably 1.0~300.0μm, preferably 2.0~200.0μm.

The thickness ratio of the coating layer on the flat portion can be measured as follows.

First, a sample with a cut surface as the observation surface is taken from the center of the plate surface of the coated mesh steel plate to be measured, in the center of the long side direction of the convex part. The cut surface is orthogonal to the long side direction of the convex part and cut along the plate thickness direction (specifically, it is the cut surface equivalent to the F-F section in Figure 3A).

Next, the sample is embedded in the resin, and the observation surface of the sample is observed with a scanning electron microscope (SEM) at a magnification of 500 times or 2000 times (see FIG. 1A and FIG. 1B ).

Next, measure the thickness of the coating layer on the left and right flat parts, and calculate the ratio of the thickness of the coating layer on the left side to the thickness of the coating layer on the right side.

Here, the coating thickness of the left and right flat parts is measured at a distance of 3 mm (see FP in Figure 1) from the boundary between the convex part and the flat part (specifically, the edge of a pair of flat parts that are parallel to the plate surface in the plate thickness direction (see EG in Figure 1A)).

In addition, in Figure 1, B’ represents the base textured steel plate, C’ represents the plating layer, Q represents the convex part, and P represents the flat part.

This operation was performed on three samples taken at a distance of 100 mm or more from each other, and the arithmetic mean of the "ratio of the thickness of the plating layer on the left/the thickness of the plating layer on the right side" was determined as "the ratio of the flat part" Plating layer thickness ratio".

-Formula 1 and Formula 2-

In the plated textured steel plate of the present disclosure, if the texture height T-t represented by the difference between the thickness T of the base textured steel plate in the convex portion and the thickness t of the base textured steel plate in the flat portion is too large, the convex portion and The difference in thermal expansion of the flat portion will become too large. As a result, deformation occurs due to heating and cooling before the immersion plating bath, resulting in deterioration of flatness. Therefore, the texture height T-t is set to be equal to or less than the thickness of the base textured steel plate in the flat portion.

On the other hand, in order to ensure the function of the coated mesh steel plate (such as anti-slip properties), the mesh height T-t is limited to be greater than 0.5mm.

In the plated corrugated steel plate of the present disclosure, when the plated corrugated steel plate is allowed to stand still, if the gap height x from the resting surface is too large, the flatness will deteriorate. Therefore, the gap height x is set to the texture height T-t×1.5 or less.

Furthermore, if the flatness of the coated mesh steel plate disclosed in the present invention deteriorates, the thickness ratio of the coating layer of the flat portion on the left and right of the protrusion will increase, and the corrosion resistance and processability will also deteriorate.

Therefore, the texture height T-t and the gap height x must satisfy the following equations 1 and 2; the texture height T-t is: let the thickness of the base texture steel plate in the convex part be T and let the aforementioned base mesh in the flat part The height of the texture when the thickness of the corrugated steel plate is t; the gap height high.

Formula 1: x/(T-t)≦1.5

Formula 2: 0.5<T-t≦t

The units of the base mesh steel plate thickness T, t, and gap height x in Formula 1 and Formula 2 are "mm".

In Formula 1, from the perspective of improving flatness, corrosion resistance, and processability, the value of "x/(T-t)" should be less than 1.2, and preferably less than 1.0. In addition, from the same perspective, the value of "x/(T-t)" should be close to 0.

In Formula 2, from the viewpoint of improving flatness, corrosion resistance and processability, the "T-t" value is preferably 0.8t or less, and more preferably 0.7t or less. In addition, the lower limit of the texture height T-t is set considering improving the function of the plated textured steel plate (such as slip resistance).

Here, the thickness t of the base corrugated steel plate in the flat portion should be 1.6~6.0mm.

From the viewpoint of flatness, corrosion resistance and workability, the gap height x is preferably 3.0 mm or less, preferably 2.0 mm or less.

In addition, if the function of the coated textured steel plate (such as anti-slip properties) is taken into consideration, the area occupancy rate of the protrusion (i.e. the textured part) should be 15~60%.

The base mesh steel plate thickness T in the convex part, the base mesh steel plate thickness t in the flat part, the mesh height T-t and the gap height x can be measured as follows.

First, take a 300mm square sample from the center of the plate surface of the measured grid-coated steel plate.

Next, the collected sample is placed still on a horizontal surface (standing surface). Among them, the surface of the sample opposite to the resting surface is defined as: the surface equivalent to the surface of the plated textured steel plate without convex parts and flat parts.

Observe the static sample from the horizontal direction of the static surface, and measure the gap height between the static surface and the plate surface of the sample opposite to the static surface (refer to Figure 2).

Furthermore, this operation is performed from the four sides of the sample, and the maximum gap height is regarded as the gap height x.

Here, in Figure 2, CS represents the sample of the coated mesh steel plate, and Su represents the static surface.

On the other hand, from a 300 mm square sample, a cutting surface is taken from the center of the long side direction of the convex part to form the observation surface of the sample. The cutting surface is perpendicular to the long side direction of the convex part and cut along the plate thickness direction (specifically, it is the cutting surface equivalent to the F-F section in Figure 3A).

Next, the sample was embedded in the resin and the observation surface of the sample was observed using an optical microscope at a magnification of 25 times (see Figure 1).

Next, the thickness of the base mesh steel plate in the center of the width direction of the convex portion and the thickness of the base mesh steel plate in the center of the width direction of the flat portion are measured.

Furthermore, this operation was carried out for three samples, and the maximum value of the obtained "thickness of the base corrugated steel plate in the width direction center part of the convex part" and "the thickness of the base corrugated steel plate in the width direction center part of the flat part" was The values are respectively determined as the thickness T of the base textured steel plate in the convex part and the thickness t of the base textured steel plate in the flat part, and the difference between them is the texture height T-t.

(Manufacturing method of plated corrugated steel plate)

Hereinafter, an example of the manufacturing method of the plated corrugated steel plate of this disclosure is demonstrated.

This disclosure discloses a manufacturing method of plated corrugated steel plate, for example: heating the base corrugated steel plate Heating to a temperature above the plating bath temperature +20°C and below 850°C at a speed of 5~20°C/second and maintaining it, and then cooling to a temperature above the temperature of the plating bath and below +10°C at a cooling rate of 5~20°C/second Within the range, the cooled base corrugated steel plate is then immersed in the plating bath. After taking it out from the plating bath, if the temperature of the plating bath is higher than 500°C, cool it to 500°C at a cooling rate of 5~20°C/second. And produce plated mesh steel plate.

Here, plating is performed by a continuous molten metal plating method such as the Sendzimir process.

An example of a specific manufacturing method is as follows.

First, prepare a base textured steel plate whose texture height T-t satisfies Equation 1.

Next, after the base mesh steel plate is pickled, the base mesh steel plate is heated and maintained at the heating attained temperature.

Here, the base textured steel plate may also be pre-plated (e.g. Ni pre-plated) after pickling and before heating.

The heating temperature is set to be above the bath temperature + 20°C and below 850°C. By setting the heating temperature below 850°C, deformation of the base mesh steel plate is suppressed and flatness is improved.

The heating speed is set at 5~20℃/second. By heating gently at a heating rate of 20°C/second or less, the convex portions and flat portions of the base corrugated steel plate will heat up evenly, thereby suppressing deformation caused by the difference in thermal expansion between the convex portions and the flat portions. As a result, further deterioration of flatness is suppressed.

On the other hand, if the heating speed is too slow, it will be difficult for the convex and flat parts of the base mesh steel plate to heat up evenly, and deformation will easily occur due to the difference in thermal expansion between the convex and flat parts. Therefore, the heating speed is set at 5℃/second.

Without pre-plating, the heating maintenance time is set to 10~120 seconds. By setting the heating maintenance time to 10~120 seconds, the surface oxide film can be reduced to improve the plating properties.

The base corrugated steel plate is heated by, for example, electric heating, non-oxidation direct heating, or radiation heating.

Next, cool the base textured steel plate to a temperature above the bath temperature and below the bath temperature +10.

The cooling rate is set at 5~20℃/second. By cooling gently at a cooling rate of less than 20℃/second, the convex and flat parts of the base mesh steel plate will be cooled evenly, and deformation caused by the difference in thermal shrinkage between the convex and flat parts will be suppressed. As a result, further deterioration of flatness will be suppressed.

On the other hand, if the cooling rate is too slow, it will be difficult for the convex portion and the flat portion of the base corrugated steel plate to be cooled uniformly, and deformation caused by the difference in thermal shrinkage between the convex portion and the flat portion will easily occur. Therefore, the cooling rate is set to 5°C/sec.

The cooling of the base textured steel plate is carried out, for example, by nitrogen cooling.

By heating and cooling the base textured steel plate before plating in the above manner, deterioration in flatness is suppressed, and therefore a plated textured steel plate having a gap height x that satisfies Equation 2 can be obtained.

Next, the cooled base textured steel plate is immersed in a plating bath, the chemical composition of which is equivalent to the chemical composition of the coating layer in the coated textured steel plate disclosed above.

Then, after the base textured steel plate is removed from the plating bath, the coating adhesion is adjusted by wiping and cooled.

When the bath temperature is below 500°C, there are no special restrictions on the cooling conditions after plating. On the other hand, when the bath temperature is higher than 500°C, the cooling rate from plating to 500°C is set at 5~20°C/second. By cooling gently at a cooling rate of less than 20°C/second, the convex and flat parts of the base mesh steel plate will be cooled uniformly, and deformation caused by the difference in thermal expansion between the convex and flat parts will be suppressed. As a result, further deterioration of flatness will be suppressed.

On the other hand, if the cooling rate is too slow, it will be difficult for the convex portion and the flat portion of the base corrugated steel plate to be cooled uniformly, and deformation caused by the difference in thermal expansion between the convex portion and the flat portion will easily occur. Therefore, the cooling rate is set to 5°C/sec.

In addition, there are no special restrictions on cooling conditions below 500°C.

Cooling after plating is performed by, for example, air cooling or nitrogen cooling.

Here, if the flatness of the base textured steel plate is poor, when wiping after plating, the wiping spray The distance between the wiping nozzel and the base corrugated steel plate will change depending on the position, so there will be local thinner and thicker areas of the plating layer, and the thickness of the plating layer will vary between the flat parts. Varies.

In addition, when gas cooling is performed, the distance between the cooling nozzle and the base textured steel plate will also change depending on the position, so there will be local thinner and thicker areas of the coating layer, resulting in uneven thickness of the coating layer between flat parts.

In particular, compared with the Zn-based plating bath, the viscosity of the Zn-Al-Mg alloy-based plating bath is lower, so the thickness of the plating layer is prone to variation.

However, since further deterioration of the flatness of the base patterned steel sheet has been suppressed during heating and cooling before the immersion plating bath as described above, even if Zn-Al-Mg-based plating is performed, the plating layer will remain between the flat portions. The layer thickness is not easy to vary, and a Zn-Al-Mg-based plated mesh steel plate can be obtained. The ratio of the thickness of the coating layer to the flat parts on the left and right of the convex part (the thickness of the coating layer on the left side/the thickness of the coating layer on the right side) layer thickness) meets the above range.

The following describes the subsequent processing of the coated textured steel plate that can be applied to the present disclosure.

The coated textured steel plate disclosed herein can also form a film on the coating layer. One layer or two or more layers of the film can be formed. As the type of film directly above the coating layer, there can be cited: chromate film, phosphate film and chromate-free film. The chromate treatment, phosphate treatment and chromate-free treatment used to form the films can be performed by known methods.

Chromate treatment includes the following: electrolytic chromate treatment, which forms a chromate film through electrolysis; reactive chromate treatment, which uses reaction with the material to form a film and then washes off the excess treatment liquid; Coating-type chromate treatment is applied to the object to be coated and then dried without washing to form a film. Either treatment can be used.

As electrolytic chromate treatment, the following electrolytic chromate treatment can be used for example: chromic acid, silica oxide sol, resin (acrylic resin, vinyl ester resin, vinyl acetate acrylic emulsion, carboxylated styrene butadiene latex, diamine Isopropylamine modified epoxy resin, etc.) and hard silicon oxide.

Examples of phosphate treatment include zinc phosphate treatment, calcium zinc phosphate treatment, and manganese phosphate treatment.

Chromate-free treatment is particularly suitable as it does not place a load on the environment. There are two types of chromate-free treatment: electrolytic chromate-free treatment, which forms a chromate-free film through electrolysis; and reactive chromate-free acid, which forms a film by reacting with the material and then washes away the excess treatment solution. Salt treatment: a coating type chromate-free treatment in which the treatment liquid is applied to the object to be coated and then dried without washing to form a film. Either treatment can be used.

It is also possible to further have one or more layers of organic resin films on the film directly above the plating layer. The organic resin is not limited to a specific type, and examples thereof include polyester resin, polyurethane resin, epoxy resin, acrylic resin, polyolefin resin or modified products of these resins. The so-called modified product here refers to the resin after reacting the reactive functional groups contained in the structure of the resin with other compounds (monomers or cross-linking agents, etc.). The other compounds are contained in the structure and can be combined with The functional group is a functional group that reacts.

As the organic resin, one type or a mixture of two or more types of organic resins (without modification) may be used, or at least one other type of organic resin may be modified in the presence of at least one type of organic resin. , use one type of organic resin thus obtained or mix two or more types of the obtained organic resins. In addition, the organic resin film may contain any color pigment or anti-rust pigment. Those dissolved or dispersed in water to become water-based can also be used.

Implementation example

The embodiments of the present disclosure will be described. However, the conditions in the embodiments are examples of conditions adopted to confirm the feasibility and effects of the present disclosure, and the disclosure is not limited to this example of conditions. Various conditions may be adopted for this disclosure as long as the purpose of cost disclosure is achieved without departing from the gist of this disclosure.

(Implementation example)

In order to obtain the coating layer with the chemical composition shown in Table 1 and Table 2, a predetermined amount of pure metal ingots is used, and the ingots are melted and then the coating bath is built in the atmosphere. A batch melting coating device is used to produce the coated mesh steel plate.

Then, a plated textured steel plate was produced under the conditions shown in Table 1 to Table 2. Specifically, it is as follows.

In an N ₂ -H ₂ (5%) (dew point below -40°C, oxygen concentration less than 25 ppm) environment, use electrical heating to heat the base corrugated steel plate from room temperature, and then blow N ₂ gas after maintaining it for 60 seconds. The steel plate was cooled to the plating bath temperature +10°C and then immediately immersed in the plating bath. After that, the base textured steel plate is taken out from the plating bath, and the N ₂ gas wiping pressure is adjusted so that the plating adhesion amount on the plate surface with convex parts and flat parts becomes about 250g/m ² to create a plating texture. steel plate.

In addition, as the base textured steel plate, various hot-rolled textured steel plates having different plate thicknesses T in the convex portions and plate thickness t in the flat portions are used.

The shape of the base mesh steel plate used is the same as Figure 3A to Figure 3C. In the figure, A, B, C, D, E and H are as follows.

A: The arrangement angle of the convex parts relative to the rolling direction.

B: The length of one convex part.

C: The maximum width of a convex part.

D: The minimum width of a convex part.

E: The arrangement spacing of the convex parts.

H: Height of convex portion (that is, height of mesh).

The reticulated steel plate is hot-rolled aluminum deoxidized steel, with angle A=45°, length B=25.3mm, maximum width C=5.1mm, minimum width D=2.5mm, and spacing E=28.6mm. In addition, the area occupancy rate of the convex portion is 40%.

However, the height H of the convex portion (i.e., the mesh height T-t) is determined as shown in Table 1.

In some examples, the base mesh steel sheet is a Ni pre-plated mesh steel sheet obtained by Ni pre-plating the hot rolled mesh steel sheet. The Ni adhesion amount is set to 1 g/m ² to 3 g/m ² . In addition, regarding the example of using the Ni pre-plated mesh steel sheet as the base mesh steel sheet, it is marked as "Pre-Ni" in the "Base mesh steel sheet" column in the table.

-Various measurements-

Regarding the obtained coated mesh steel plate, the following items were measured according to the method described above.

‧The thickness ratio of the coating layer on the flat part on the left and right of the convex part (the thickness of the coating layer on the left side/the thickness of the coating layer on the right side)

‧Thickness T of the base mesh steel plate in the convex part (marked as "convex part thickness T" in the table)

‧The thickness of the base corrugated steel plate in the flat part is t (marked as "flat part thickness t" in the table)

‧Gap height x

-flatness-

In order to compare the flatness, the sample is placed on a flat table and pressed from above to evaluate the degree of shaking. If there is no shaking, it is rated as "A+", if there is slight shaking, it is rated as "A", and if there is severe shaking, it is rated as "NG".

-Corrosion resistance-

In order to compare the corrosion resistance, the manufactured samples were subjected to the corrosion promotion test (JASO M609-91) for 30 cycles, and then the average area ratio of red rust was evaluated. The area ratio of red rust was rated "A+" if it was less than 3.0%, "A" if it was less than 5.0%, "B" if it was less than 7.0%, and "NG" if it was greater than 7.0%.

-Processability-

In order to evaluate the processability of the coating layer, the plated corrugated steel plate was bent in a 90° V-shape with the plate surface provided with convex parts and flat parts as the peak side, and a cellophane tape with a width of 24 mm was pressed against the V Then tear off the curved peak of the word. The area ratio of the plating layer torn off from the plated corrugated steel plate and attached to the cellophane tape relative to the area of the pressed cellophane tape is 3.0% or less and is rated as "A+", and 5.0% or less is rated as "A" ”, if it is less than 10.0%, it will be rated as “B”, and if it is more than 10.0%, it will be rated as “NG”.

The embodiments are listed in Table 1 and Table 2.

From the above results, it can be seen that compared with the comparative examples, the examples of the plated mesh steel plates according to the present disclosure are superior in flatness, corrosion resistance and workability.

In addition, Test No. 97 (Comparative Example) is an example in which the heating reaching temperature before plating is as high as 850°C or more.

Test No.98 (comparative example) is an example where the heating rate before plating is as high as 30℃/second.

Test No. 99 (comparative example) is an example in which the cooling rate after heating before plating is as high as 30° C./second.

Test No. 100 (comparative example) is an example in which the heating rate before plating and the cooling rate after heating before plating are as high as 30℃/second.

Test No. 101 (comparative example) is an example where the cooling rate after plating is as high as 30℃/second.

Test No. 102 (comparative example) is an example where T-t is larger than the plate thickness t.

Test Examples No. 103 (Comparative Example) to No. 105 (Comparative Example) are examples in which the heating rate before plating, the cooling rate after heating before plating, and the cooling rate after plating are slow.

The test No. 97~103 all meet the coating composition disclosed in this disclosure, but the coating thickness ratio and "x/(T-t)" value of the flat part are larger, so the flatness, corrosion resistance and processability are deteriorated.

The above has referred to the attached drawings and described in detail the preferred embodiments and examples of the present disclosure, but the present disclosure is not limited to the examples. It should be understood that anyone with knowledge of the technical field to which the present disclosure belongs can think of various changes or modifications within the scope of the technical ideas recorded in the scope of the patent application, and know that these should also belong to the technical scope of the present disclosure.

B’: Base mesh steel plate

C’: coating layer

Q:convex part

P: Flat part

T: Thickness of the base corrugated steel plate in the convex part

t: Thickness of the base corrugated steel plate in the flat part

EG: The boundary between the convex part and the flat part

FP: 3mm away from the boundary between the convex part and the flat part

FT: The thickness of the plating layer in the flat part

Claims (3)

A Zn-Al-Mg coated mesh steel plate has a base mesh steel plate and a coating layer, wherein the base mesh steel plate has a convex portion and a flat portion on one of the plate surfaces, the coating layer is arranged on the plate surface of the base mesh steel plate having the convex portion and the flat portion, and the coating layer includes a Zn-Al-Mg alloy layer; The coating layer has a chemical composition consisting of the following: In terms of mass%, Zn: greater than 65.0%, Al: greater than 1.0% and less than 25.0%, Mg: greater than 1.0% and less than 12.5%, Sn: 0%~5.0%, Bi: 0%~less than 5.0%, In: 0%~less than 2.0%, Ca: 0%~3.00%, Y: 0%~0.5%, La: 0%~less than 0.5%, Ce: 0%~less than 0.5%, Si: 0%~less than 2.5%, Cr: 0%~less than 0.25%, Ti: 0%~less than 0.25%, Zr: 0%~less than 0.25%, Mo: 0%~less than 0.25%, W: 0%~less than 0.25%, Ag: 0%~less than 0.25%, P: 0%~less than 0.25%, Ni: 0%~less than 0.25%, Co: 0%~less than 0.25%, V: 0%~less than 0.25%, Nb: 0%~less than 0.25%, Cu: 0%~less than 0.25%, Mn: 0%~less than 0.25%, Li: 0%~less than 0.25%, Na: 0%~less than 0.25%, K: 0%~less than 0.25%, Fe: 0%~5.0%, Sr: 0%~less than 0.5%, Sb: 0%~less than 0.5%, Pb: 0%~less than 0.5%, B: 0%~less than 0.5% and impurities; In the central part of the long side direction of the aforementioned protrusion, a cut surface is observed that is perpendicular to the long side direction of the aforementioned protrusion and cut along the plate thickness direction. At this time, the thickness ratio of the coating layer on the aforementioned flat part on the left and right of the aforementioned protrusion (the thickness of the coating layer on the left side/the thickness of the coating layer on the right side) is greater than 0.2 and less than 5.0; and The mesh height T-t and the gap height x satisfy the following formulas 1 and 2; the mesh height T-t is: the mesh height when the thickness of the aforementioned base mesh steel plate in the aforementioned convex portion is T and the thickness of the aforementioned base mesh steel plate in the aforementioned flat portion is t; the gap height x is: when the coated mesh steel plate is stationary, the gap height between the stationary surface and the plate surface of the coated mesh steel plate opposite to the aforementioned stationary surface; Formula 1: x/(T-t)≦1.5; Formula 2: 0.5＜T-t≦t; The units of the base mesh steel plate thickness T, t, and gap height x in Formulas 1 and 2 are "mm". The Zn-Al-Mg coated mesh steel plate of claim 1, wherein the Al concentration is greater than 5.0% and less than 25.0%, and the Mg concentration is greater than 3.0% and less than 12.5%. For example, the Zn-Al-Mg plated corrugated steel plate of Claim 1 or Claim 2, wherein the aforementioned coating layer includes an Al-Fe alloy layer between the aforementioned base corrugated steel plate and the aforementioned Zn-Al-Mg alloy layer. .