TW201920714A - Hot dipped checkered steel plate and producing method thereof - Google Patents

Abstract

A hot dipped checkered steel plate includes a base steel, a Ni coating layer, and a hot dip coating layer, and includes a convex area and a flat area in a plate surface. A thickness of the Ni coating layer in the convex area is 0.07 to 0.4 [mu]m, a thickness of the Ni coating layer in the flat area is 0.05 to 0.35 [mu]m, and the thickness of the Ni coating layer in the convex area is more than 100% and 400% or less as compared with the thickness of the Ni coating layer in the flat area.

Description

Hot-dip plated textured steel plate and manufacturing method thereof

The invention relates to a hot-dip plated textured steel sheet and a method for manufacturing the same.
This case is based on Japanese Patent Application No. 2017-178011, which was filed in Japan on September 15, 2017, and its contents are incorporated herein by reference.

BACKGROUND OF THE INVENTION A textured steel plate is a steel plate with continuous non-slip protrusions (projections) on the surface by rolling. Generally speaking, convex portions of a certain width, a certain height, and a certain height are provided at a certain angle and a certain distance with respect to the rolling direction. Generally, a textured steel sheet is produced by hot rolling. Furthermore, they are used on the floor or steps of buses, trucks, etc., factory flooring, ship decks, temporary scaffolds or steps on construction sites, and the like.

In the past, anilox steel sheets were mostly used directly after hot rolling or after coating. If there is a special need for rust prevention, it will go through the batch type hot-dip galvanizing process using the flux method to galvanize the cutting plate of the anilox steel plate. However, the batch-type hot-dip galvanizing process not only has low productivity, but also increases the Fe-Zn alloy layer generated in the hot-dip plating step. Therefore, the workability of the plated layer is impaired, and plating cracks or plated layers are caused. Peeling may cause problems in corrosion resistance.

Compared with batch hot-dip galvanizing, continuous hot-dip galvanizing has higher productivity. Continuous hot-dip galvanizing is generally performed by passing a steel sheet heated to a predetermined temperature through a hot-dip galvanizing bath under a reducing or non-oxidizing gas environment. In addition, since the molten zinc bath contains at least about 0.05% of Al, the growth of the Fe-Zn alloy layer that can impair the processability of the plating film can be suppressed. In addition, in a conventional batch type hot-dip galvanizing using a flux method, if Al is contained in a Zn bath, Al will decompose the flux, so unplating frequently occurs, and plating cannot be performed smoothly.

In order to apply continuous hot-dip galvanizing to an anilox steel sheet, it is necessary to consider problems caused by the surface shape and the like. For example, Patent Document 1 teaches a continuous hot-dip galvanizing method for a strip-shaped textured steel plate, and particularly teaches appropriate conditions for tension in a plating line and gas wiping after hot-dip plating. At present, the textured steel plate obtained by continuous hot-dip galvanizing has been commercialized.

In recent years, in addition to hot-dip galvanized steel sheets, based on the need for better corrosion resistance compared to galvanized steel, Zn-Al, Zn-Al-Mg, Zn-Al-Mg-Si, and other molten zinc-based alloy plated steel sheets have been developed. And has been commercialized. In a form corresponding to this, it can also be observed that an anodized steel sheet is also applied to molten zinc-based alloy plating.

Patent Document 2 discloses a textured steel sheet having excellent workability and corrosion resistance, which is characterized in that a surface of the textured steel sheet has a quaternary alloy layer of Ni-Al-Zn-Fe with a thickness of 2 μm or less as a first layer, and A molten plating layer having a Zn-based alloy containing 0.1 to 1% of Al in terms of weight is used as the second layer. As a specific plating method, Patent Document 2 teaches a method for manufacturing an anilox steel sheet, which is composed of the following steps: Ni-plating the anilox steel sheet at 0.5 to 2.0 g / m ² , and then heating the The textured steel sheet is then immersed in a molten zinc bath to which 0.1 to 1% of Al is added in terms of weight for an immersion time of 1 to 30 seconds.

Patent Document 3 uses a plating bath that can be considered to be almost the same as that of Patent Document 2. However, it specifies the structure of a molten plating film obtained by the Sendzimir method. Regardless of Patent Document 2 or Patent Document 3, the use of a molten zinc-based alloy having an Al concentration of 1% or less is an essential feature. Furthermore, in Patent Literature 2 and Patent Literature 3, the Al concentration in the plating layer is 1% or less, so it is difficult to obtain the barrier corrosion prevention effect by Al, and the plating film itself cannot be expected to have significant and better corrosion resistance. Of promotion.

Patent Document 4 discloses a molten Zn-based plated textured steel sheet excellent in damage resistance, abrasion resistance, and corrosion resistance, which is characterized in that it is coated with a molten plating layer having the following composition: in mass%, containing Al: 4.0 ~ 20.0%, Mg: 1.0 ~ 4.0%, and more optionally contains Ti: 0.002 ~ 0.1% and B: 0.001 ~ 0.045%, and the remaining part is composed of Zn and unavoidable impurities. The ternary eutectic structure of the Al / Zn / ZnMg-based intermetallic compound of the plating layer is large, and the ternary eutectic is hard, so its Vickers hardness is 120 ~ 180Hv. In addition to corrosion resistance, It is also excellent in damage resistance and abrasion resistance.

As described above, in the past, most of the textured steel sheets have been used in an unplated state, and galvanizing has been performed according to needs, and attempts have also been made to apply zinc-based alloy plating instead of galvanizing. However, the case of applying Ni pre-plating to the base material steel plate and performing zinc-based alloy plating with an Al concentration greater than 1.0% after Ni pre-plating has not been discussed at all.

Patent Literature Prior Art Literature Patent Literature 1: Japanese Patent Laid-Open No. 7-11411 Patent Literature 2: Japanese Patent Laid-Open No. 6-81170 Patent Literature 3: Japanese Patent Laid-Open No. 6-248409 Patent Literature 4: Japanese Patent JP-A-11-279732

SUMMARY OF THE INVENTION Problems to be Solved by the Invention The inventors originally tried to further improve the corrosion resistance of the textured steel sheet, and also tried to apply zinc-based alloy plating to the textured steel sheet with an Al concentration greater than 1.0%. However, the results of the study clearly show that if zinc-based alloy plating with an Al concentration greater than 1.0% is applied to the textured steel plate, unplating will occur frequently. That is, it is clear that if the Al concentration of zinc-based alloy plating such as Patent Documents 2 and 3 is 1.0% or less, the occurrence of non-plating does not pose a problem. However, zinc-based alloys such as Patent Document 4 If the Al concentration to be plated is more than 1.0%, the occurrence of non-plating becomes a problem.

Specifically, the inventors originally intended to impart excellent corrosion resistance to an anilox steel sheet, and studied Zn-based alloy plating on an anilox steel sheet; generally, the Zn-based alloy plating is more corrosion resistant than Zn plating Excellent, and contains more than 1.0% Al and a small amount of Mg. In addition, during the process, the following knowledge and insights were obtained: If the Sendzimir method, which is commonly used as a fusion plating method, is used to perform fused plating of Zn-Al-Mg-based alloys with an Al concentration of more than 1.0% on an anilox steel sheet, Unplating occurred.

The present inventors believe that when a Zn-based alloy containing Al: more than 1.0% and a certain amount of Mg is melt-plated on a textured steel plate, unplating is likely to occur. This system is related to the following: steel plates and molten soup The wettability between them decreases with the increase of the Al concentration in the Zn melt; it is also related to the following: due to the peculiar cause of the hot rolling process of the anilox steel sheet.

With regard to this non-plating problem, the present inventors have tried to use Ni pre-plating which is also used in Patent Document 2. As a result of the study, the present inventors have obtained the following knowledge and insights: By performing zinc-based alloy plating after Ni pre-plating, the occurrence of non-plating can be suppressed to a certain extent. 1.0% zinc-based alloy plating, it is necessary to increase the amount of Ni adhesion in Ni pre-plating. However, on the other hand, the present inventors also obtained the following knowledge together: As a result of the above discussion, if the amount of Ni deposited in the Ni pre-plating is increased, corrosion resistance on the convex portion is caused when the hot-dip galvannealed steel plate is worn out. Sexual decline easily.

That is, the inventors have obtained the following knowledge regarding the application of zinc-based alloy plating with an Al concentration of more than 1.0% to the textured steel sheet in order to further improve the corrosion resistance.
(a) If the zinc-based alloy is plated on an anilox steel sheet with an Al concentration greater than 1.0%, unplating frequently occurs.
(b) In order to apply zinc-based alloy plating with an Al concentration greater than 1.0% to the textured steel plate, Ni pre-plating is necessary, and the amount of Ni to be deposited must be increased more than before.
(c) However, if the amount of Ni deposited by Ni pre-plating is increased on the textured steel sheet, the corrosion resistance of the convex portions tends to decrease when the hot-dip galvanized steel sheet is worn out.

In view of the above-mentioned phenomenon, the inventors' thoughts are as follows. For example, in the case where a hot-dip galvanized steel sheet is used for a base plate or the like, the wear and loss of the hot-dip plating layer on the convex portion thereof is considerably large, and the Ni-plated layer may be exposed in some cases. In addition, if the pre-plated steel sheet is plated with molten Zn or molten Zn-Al, etc., a part of the Ni will move to the plating layer or the molten soup due to the reaction with the molten soup, and part of the Ni It remained on the surface of the steel plate as a Ni plating layer. Therefore, when the amount of Ni deposited on the Ni pre-plating is large, the Ni plating layer remaining on the surface of the steel sheet after the hot-dip plating becomes thick.

Generally, the natural immersion potential is from high to low in the order of Ni, Fe, and the plating layer, but the natural immersion potential of the thinner Ni plating layer will be the mixed potential of Ni and Fe. In the Zn-based alloy hot-dip plating after Ni pre-plating, if the upper Zn-based alloy's fused-plated layer is worn out and the Ni plating layer is exposed, Galvanic will occur between the exposed portion and the vicinity of the exposed portion Corrosion (Gaffany corrosion). For example, in a hot-dip galvanized steel sheet, Galvanic corrosion occurs between the Ni-plated layer exposed on the convex portion and the hot-plated layer near the exposed portion. Even if the Ni plating layer is exposed, if the Ni plating layer is thin, the natural immersion potential of the Ni plating layer becomes a mixed potential and becomes a potential close to Fe, and the Galvanic corrosion rate between the Ni plating layer and the molten plating layer is not constant. It will be too fast. Conversely, if the Ni plating layer is thick, even if the natural immersion potential of the Ni plating layer is a mixed potential, it will actually become a potential close to Ni, so the Galvanic corrosion rate between the Ni plating layer and the molten plating layer will be Get faster. As a result, the hot-dip plating layer is easily corroded and lost.

In order to avoid confusion, in the description of this case, if there is no special statement, when "Ni plating" or "Ni plating" is used to indicate the plating layer, it means the Ni coating layer remaining after the melt plating, and "Ni pre-plated layer" and "Ni pre-plated" mean the Ni coating layer existing before the fusion plating step. In addition, in the following description of the specification of the present case, when expressions such as "fusion plating of Zn-based alloy" or "fusion plating" are used, it means "fusion plating of Zn-Al-Mg-based alloy".

An object of the present invention is to provide a hot-dip galvanized steel plate and a method for manufacturing the hot-dip galvanized steel plate. The steel sheet hardly undergoes unplating, and even if the Zn-based alloy is subjected to a loss (corrosion or abrasion) in the molten plating of the convex portion of the textured steel sheet, it exhibits excellent corrosion resistance. In addition, an object of the present invention is to provide a hot-dip plated textured steel plate and a manufacturing method thereof. The hot-dip plated textured steel plate not only satisfies the general characteristics required for the hot-dip plated textured steel plate, that is, the appearance or processing of the plated steel plate. Properties, etc., can also take into account the above-mentioned unplated suppression and corrosion resistance after loss.

Means for Solving the Problem The present inventors thought that when attempting to perform hot-dip plating of a Zn-Al-Mg-based alloy containing more than 1.0% of Al on an anilox steel plate after Ni pre-plating, although the From the viewpoint of a large amount of Ni adhesion, from the viewpoint of ensuring the corrosion resistance on the convex portions of the textured steel sheet, at least the Ni adhesion amount on the convex portions must be suppressed to a certain value or less.

When pre-plating Ni on a steel strip, electroplating is usually used. Although Ni can be precipitated out of the steel strip by the electroless method, in addition to poor productivity, elements other than Ni are mixed in a large amount in the precipitation film, which is not preferable. When electroplating a common steel strip, the anode is usually arranged in a form opposite to the surface of the steel strip that is a cathode, and electrolysis is performed to minimize the distance between the steel strip and the anode to ensure the current distribution. Uniformity and curb electricity costs.

However, when plating an anilox steel plate, the distance between the electrodes of the anilox steel plate and the anode is closer than the plane portion of the anilox steel plate, so the amount of Ni deposited on the convex portion of the anilox steel plate increases. . That is, if an anilox steel plate is electroplated to perform Ni pre-plating in a conventional electrolytic cell under conventional conditions, the amount of Ni deposited on the convex portion becomes very large. As a result, the anilox is melt-plated as a result. When the molten plating layer of the steel sheet is lost, there is a concern that significant Galvanic corrosion will occur in the convex portion.

The present inventors have found that, with regard to a hot-dip galvannealed steel sheet of a Zn-Al-Mg-based alloy containing more than 1.0% Al, the lower limit value of the thickness of the Ni pre-plated layer required to prevent unplating was determined And the upper limit of the thickness of the Ni pre-plated layer that should be limited to ensure the corrosion resistance on the convex portion, and the thickness ratio of the Ni plated layer between the convex portion and the flat portion can be specified to overcome the above problems.

The gist of the present invention is as follows.
(1) One aspect of the present invention is a hot-dip galvanized steel plate, which includes a base metal steel plate, a Ni plating layer disposed on the surface of the base metal steel plate, and a molten plating layer disposed on the surface of the Ni plating layer. The plate surface has a convex portion and a flat portion; wherein the film thickness of the Ni plating layer of the convex portion is 0.07 to 0.4 μm per one surface, and the film thickness of the Ni plating layer of the flat portion is 0.05 to 0.35 μm per single surface; The film thickness of the Ni plating layer in the convex portion is greater than 100% and less than 400% with respect to the film thickness of the Ni plating layer in the flat portion, and the adhesion amount of the molten plating layer is 60 to 400 g / m ² per one side, and The chemical composition of the melt-plated layer contains Al: more than 1.0% and less than 26%, Mg: 0.05 to 10%, Si: 0 to 1.0%, Sn: 0 to 3.0%, and Ca: 0 to 1.0% in mass%. , And the remaining part is composed of Zn and impurities.
(2) In the hot-dip galvanized steel sheet as described in (1) above, the film thickness of the Ni plating layer in the convex portion may be greater than 100% and not more than 300% of the film thickness of the Ni plating layer in the flat portion.
(3) In the hot-dip galvannealed steel sheet according to (1) or (2) above, the film thickness of the Ni plating layer at the convex portion may be 0.07 to 0.3 μm per one side.
(4) In the hot-dip galvanized steel sheet according to any one of the above (1) to (3), the chemical composition of the hot-dip plating layer may contain Al: 4.0 to 25.0%, Mg: 1.5 to 5% by mass. 8.0%.
(5) In the hot-dip galvanized steel sheet according to any one of (1) to (4) above, the chemical composition of the hot-dip plating layer may include at least one of the following in terms of mass%: Si: 0.05 to 1.0%, Sn: 0.1 ~ 3.0%, Ca: 0.01 ~ 1.0%.
(6) In the hot-dip galvanized steel sheet according to any one of the above (1) to (5), when viewed from the thickness direction, the coverage ratio of the hot-dip plating layer relative to the surface of the board may be 99 in terms of area%. ~ 100%.
(7) A method for manufacturing a fusion-plated textured steel sheet according to one aspect of the present invention is a method for manufacturing the textured steel sheet according to any one of (1) to (6) above, which comprises the following steps: a rolling step, It provides convex portions and flat portions to the rolled surface of the steel plate; a pre-plating step, which performs Ni pre-plating on the steel plate after the rolling step; and a molten plating step, which applies the steel plate after the pre-plating step. In the pre-plating step, the rolled surface of the steel plate and the anode surface are arranged to face each other, and the distance between the protrusions of the rolled surface and the anode is controlled to 40 to 100 mm, and then Ni plating is performed on an average of 0.5 to 3 g / m ² of plating adhesion amount per one side; in the hot-dip plating step, after the steel sheet is heated, the steel sheet is immersed in the hot-dip plating bath to make each single side The continuous plating is carried out under the condition that the average deposition amount is 60 to 400 g / m ^2. The above-mentioned molten plating bath contains Al in an amount of more than 1.0% and less than 26%, and Mg: 0.05 to 10 in terms of mass%. %, Si: 0 to 1.0%, Sn: 0 to 3.0%, and Ca: 0 to 1.0%, and the remainder is composed of Zn and impurities.
(8) In the method for manufacturing a hot-dip galvanized steel sheet as described in (7) above, in the pre-plating step, the distance between the electrodes may be controlled to 45 to 100 mm.

ADVANTAGE OF THE INVENTION According to the said aspect of this invention, since a molten-plating layer contains more than 1.0% of Al, excellent corrosion resistance can be obtained. In addition, the film thickness of a Ni-plating layer is controlled, and it can suppress unplated It also occurs, and corrosion of the Ni plating layer when the molten plating layer is worn out and the Ni plating layer is exposed can be suppressed. As a result, it is possible to suppress the life cycle cost of a base plate, a plank, a structure, or other components as a hot-dip plated textured steel plate.

Embodiments of the Invention Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the configuration disclosed in this embodiment, and various changes can be made without departing from the spirit of the present invention. In addition, the following numerical limitation ranges, and the lower limit value and the upper limit value are included in this range. Values displayed as "greater than" or "less than" are not included in the range.

The hot-dip galvanized steel sheet of this embodiment has a base metal steel sheet, a Ni plating layer disposed on the surface of the base metal steel sheet, and a Zn-based (Zn-Al-Mg based) alloy disposed on the surface of the Ni plating layer Layer, and has a convex portion and a flat portion on the plate surface. In addition, the film thickness of the Ni plating layer at the convex portion is 0.07 to 0.4 μm per one side, the film thickness of the Ni plating layer at the flat portion is 0.05 to 0.35 μm per one surface, and the film of the Ni plating layer at the convex portion is The thickness is greater than 100% and less than 400% with respect to the film thickness of the Ni plating layer in the flat portion. In addition, the adhesion amount of the hot-dip plating layer is 60 to 400 g / m ² per one side, and the chemical composition of the hot-dip plating layer contains Al as a mass%: more than 1.0% and less than 26%, and Mg: 0.05 to 10%. , Si: 0 to 1.0%, Sn: 0 to 3.0%, and Ca: 0 to 1.0%, and the remainder is composed of Zn and impurities.

In addition, on the Ni plating layer side of the hot-dip plating layer, a thin intermetallic compound may be formed based on the reaction between the molten soup (the Zn-based alloy's hot-dip plating bath) and the steel plate after Ni pre-plating. Layer, and its composition will vary with the composition of the Zn-based alloy's molten plating bath. In the present embodiment, the so-called "fusion coating layer of a Zn-based alloy" is used in the sense that the intermetallic compound layer is included.

First, the hot-dip plating layer of the hot-dip plating anilox steel sheet according to this embodiment will be described in detail.

The hot-dip plating layer is a Zn-based alloy, and its chemical composition contains, in mass%, Al: more than 1.0% and less than 26%, and Mg: 0.05 to 10%.

Al (aluminum) is important in ensuring the corrosion resistance of the molten plating layer, and it can also prevent oxidation of the molten soup or inhibit the generation of Fe-Zn scum. Therefore, the Al concentration of the hot-dip plating layer is set to be greater than 1.0%. On the other hand, if the concentration of Al in the plating bath increases, the melting point will increase and the temperature of the molten soup will need to be increased. In addition, if the concentration of Al exceeds 26%, it will become difficult to ensure the beautiful appearance of the surface of the plating layer, and it will also easily cause Degradability. Therefore, the Al concentration of the hot-dip plating layer is set to 26% or less. From the viewpoint of corrosion resistance, the Al concentration of the hot-dip plating layer is preferably set to 4.0% or more. From the viewpoint of processability, the Al concentration of the hot-dip plating layer is preferably 25.0% or less, and more preferably 21.0% or less.

Mg (magnesium) will form a stable corrosion product in a corrosive environment, and form a barrier layer against corrosion, making the corrosion resistance more excellent. If the Mg concentration is less than 0.05%, the effect is poor. Therefore, the Mg concentration in the molten plating layer is set to 0.05% or more. On the other hand, as the concentration of Mg in molten soup increases, the oxidation of molten soup is promoted. Therefore, the Mg concentration in the hot-dip plating layer is set to 10% or less. In addition, if the Mg concentration exceeds 10%, the influence of an increase in the amount of oxide-based scum generation is also included, and it becomes difficult to ensure the aesthetic appearance of the surface properties of the plating layer. The lower limit of the Mg concentration is preferably 0.5%, more preferably 1%, still more preferably 1.5%, and even more preferably 2.0%. The preferable upper limit of the Mg concentration is 8.5%, more preferably 8.0%, and even more preferably 6.0%.

The chemical composition of the fused-plated layer of the fused-plated anilox steel sheet according to this embodiment contains Al and Mg as the above-mentioned basic elements, and the remainder is composed of Zn and impurities. For example, in the hot-dip plating layer, the Zn concentration is 64 to 98.95% in terms of mass%. The hot-dip plating layer may also contain 1.0% or less of Si, 3.0% or less of Sn, and 1.0% or less of Ca as a selective element in place of a part of Zn in the remaining portion.

Si (silicon) can suppress the growth of the interface alloy phase formed at the interface with the base material steel sheet, contribute to the improvement of workability, and can suppress the oxidation of Mg. In addition, it can also form Mg and Mg ₂ Si. Helps improve corrosion resistance. Therefore, the Si concentration of the hot-dip plating layer may be set to 0 to 1.0%. In order to obtain the above-mentioned effects of better Si, it is necessary to contain Si in an amount of 0.05% or more, and preferably 0.1% or more. On the other hand, even if the Si concentration exceeds 1.0%, the above effects are saturated. A preferable upper limit of the Si concentration is 0.6%.

Sn (tin) can form Mg and Mg ₂ Sn, and also helps to improve the corrosion resistance, especially the end surface corrosion resistance. Therefore, the Sn concentration of the hot-dip plating layer may be set to 0 to 3.0%. If the above-mentioned effect of Sn is desired, it should contain 0.1% or more of Sn, and preferably 0.3% or more. On the other hand, when the Sn concentration exceeds 3.0%, the corrosion resistance is liable to be lowered, and the corrosion resistance of the flat portion is particularly likely to be lowered. A preferable upper limit of the Sn concentration is 2.4%.

Ca (calcium) is effective in preventing oxidation of the plating bath surface. Compared with the case without Mg, the molten soup of Zn-Al-Mg series alloy tends to be easily oxidized. By containing Ca, the oxidation of the plating bath surface can be better suppressed. Therefore, the Ca concentration of the hot-dip plating layer may be set to 0 to 1.0%. And the Ca concentration should be above 0.01%, more preferably above 0.1%. On the other hand, if the Ca concentration exceeds 1.0%, the precipitation of Ca-based intermetallic compounds will increase, which may reduce the corrosion resistance, especially the food resistance of the flat portion. A preferable upper limit of the Ca concentration is 0.7%.

Regarding the chemical composition of the hot-dip plating layer, the remainder of the basic element and the selective element is composed of Zn and impurities. The term "impurity" refers to a substance mixed from a raw material or a manufacturing environment. For example, in the hot-dip plating layer of the hot-dip galvannealed steel sheet of this embodiment, Ni, Fe, and the like are dissolved from the surface of the steel sheet into the plating bath, and become impurities of the Zn-based alloy. In addition, for example, the molten plating layer may contain Ni derived from the Ni pre-plated layer, and the Ni concentration may be 0.01 to 0.3% in terms of mass%. Impurities may be allowed to be contained in the hot-dip coating layer of the hot-dip plating anilox steel sheet according to this embodiment as long as the target properties are not hindered.

In addition, a Ni-Al-based intermetallic compound layer may be formed at the interface between the hot-dip plating layer and the Ni plating layer. In this embodiment, this intermetallic compound layer is regarded as a part of a molten plating layer.

In this embodiment, the average adhesion amount of the hot-dip plating layer is 60 g / m ² or more per one side. The average adhesion amount refers to the average adhesion amount of the convex portion and the flat portion including the hot-dip galvanized steel sheet. That is, it means the amount of adhesion per projected area ignoring the bulge of the convex portion of the hot-dip galvanized steel plate. When the average adhesion amount of the hot-dip plating layer is less than 60 g / m ² , the corrosion resistance is insufficient. The upper limit of the average adhesion amount of the molten plating layer is not necessarily limited, but excessive adhesion of the molten plating layer will cause the plating drooping to become obvious, thereby deteriorating the appearance. Therefore, the average adhesion amount of the molten plating layer should be set to 400g / m ² or less on one side.

In addition, in the present embodiment, when the hot-dip galvanized steel sheet is viewed from the thickness direction, the coverage of the hot-dip plating layer is preferably 99 to 100% in terms of area% of the plate surface. As long as the coverage of the hot-dip plating layer is 99% or more in terms of area%, it can be determined that the occurrence of non-plating has been satisfactorily suppressed.

Next, the Ni plating layer of the hot-dip galvannealed steel sheet of this embodiment will be described in detail.

The Ni plating layer is a Ni pre-plated layer formed on the surface of the base material steel plate in advance in order to prevent unplating in the fusion plating step, and remains in the base material steel plate and the molten plating layer after the hot plating. Between layers.

The Ni plating layer is, for example, a region where the contrast between the base metal steel sheet and the hot-dip plating layer is light-colored when the cross-section of the hot-dip galvanized steel sheet is observed with a reflected electron image of a scanning electron microscope (SEM). (Shown in white range). In this embodiment, a Ni-containing intermetallic compound layer may be formed at the interface between the Ni plating layer and the base steel plate, and a Ni-containing interlayer may be formed at the interface between the Ni plating layer and the molten plating layer. The intermetallic compound layer is not included in the Ni plating layer.

The chemical composition of the Ni plating layer contains Ni, and the remainder is made of impurities. In addition, for example, the Ni concentration of the Ni plating layer is preferably 50 to 100% in terms of mass%. The term "impurity" refers to a substance mixed from a raw material or a manufacturing environment. For example, the Ni plating layer of the hot-dip galvannealed steel sheet of the present embodiment contains impurities such as diffusion of Fe from the base steel sheet.

In this embodiment, when viewed on a cutting plane parallel to the cutting direction in the thickness direction, the thickness of the Ni plating layer of the convex portion of the hot-dip plating anilox steel sheet must be 0.4 μm or less per single surface on average. If the film thickness is more than 0.4 μm, the molten plating layer of the Zn-based alloy is lost on the convex portion and the Ni plating layer is exposed, and the corrosion resistance is reduced. The thickness of the Ni plating layer of the convex portion is preferably 0.3 μm or less. On the other hand, the lower limit of the thickness of the Ni plating layer of the convex portion is set to be 0.07 μm or more on average per side. If the film thickness is less than 0.07 μm, non-plating may occur on the convex portion. The thickness of the Ni plating layer of the convex portion is preferably 0.1 μm or more.

In addition, when viewed on a cut surface that is parallel to the cut direction in the thickness direction, the thickness of the Ni plating layer of the flat portion of the hot-dip plated textured steel sheet must be 0.05 μm or more per single surface on average. If the film thickness is less than 0.05 μm, non-plating on the flat portion may occur. On the other hand, the upper limit of the thickness of the Ni plating layer in the flat portion is set to be 0.35 μm or less on average per one surface. If the film thickness is more than 0.35 μm, the effect of improving the plating adhesion on the flat surface portion is saturated, which is not economical.

In addition, in this embodiment, when viewed on a cutting plane parallel to the thickness direction and the cutting direction, the Ni plating film thickness of the convex portion must be greater than 100% and less than 400% of the Ni plating layer film thickness of the flat portion. .

As described above, if conventional plating conditions are used, in the case of a textured steel sheet, Ni is preferentially attached to the convex portion rather than the flat portion. For example, the present inventors have confirmed that if the distance between the convex portion of the textured steel plate and the anode is less than 40 mm as in the conventional method, the thickness of the Ni plating layer having the convex portion is greater than that of the Ni plating on the flat portion. When the film thickness is over 2000%.

However, as described above, the present inventors have found that in order to improve the corrosion resistance after the loss of the convex portion, it is necessary to prevent the thickness of the Ni plating layer of the convex portion from becoming too thick, and on the other hand, it is necessary to ensure a certain degree The thickness of the Ni plating layer on the flat portion is suppressed to prevent non-plating on the flat portion. That is, in this embodiment, the film thickness ratio of the Ni plating layer of the convex portion with respect to the flat portion (the film thickness of the convex portion ÷ the film thickness of the flat portion × 100) is larger than that of the conventional molten plated anilox steel plate. Come small.

If the film thickness ratio of the Ni plating layer of the convex portion to the flat portion (the film thickness of the convex portion ÷ the film thickness of the flat portion × 100) is greater than 400%, it becomes difficult to better balance the unplated portion on the flat portion. In this embodiment, the film thickness ratio of the Ni plating layer of the convex portion to the flat portion is set to 400% or less. The film thickness ratio of the Ni plating layer of the convex portion to the flat portion is preferably 350% or less, more preferably 300% or less, and most preferably 250% or less.

On the other hand, due to the shape of the anilox steel plate, it is practically difficult to reduce the thickness of the Ni plating layer of the convex portion to the thickness of the Ni plating layer of the flat portion or to make the convex portion and the flat portion thinner. The thickness of the Ni plating layer is the same. Therefore, in this embodiment, the film thickness ratio of the Ni plating layer of the convex portion to the flat portion is set to be greater than 100%.

In addition, by controlling the film thickness ratio of the Ni plating layer of the convex portion to the flat portion within the above range, not only the effect of suppressing unplating on the flat portion and the corrosion resistance after loss on the convex portion can be obtained, It is also possible to increase the amount of Ni deposited in the necessary region (planar portion) and reduce the amount of Ni deposited in the unnecessary region (convex portion). Therefore, Ni, which is a limited resource, can be effectively utilized.

Next, the base material steel plate of the hot-dip galvanized steel plate of this embodiment will be described in detail.

In this embodiment, the base material steel plate (the original plate to be plated) is a textured steel plate. The textured steel sheet is generally provided with the shape of a convex portion by hot rolling. The steel type of the base material steel plate is not particularly limited, and generally, a steel type equivalent to the rolled steel for general structure specified in JIS G3101 is used. The convex shape of the anilox steel sheet can be imparted, for example, by transferring the concave shape formed on the active roll to the surface of the steel sheet in the completion stage of hot rolling. In this embodiment, it is not necessary to limit the texture height (the height of the convex portion) or the occupation ratio of the texture portion (the convex portion). However, in consideration of the anti-slip viewpoint and usability as a base plate, the texture is used. The height is set to 0.5 to 3.5 mm, and the area occupancy of the textured portion is set to 15 to 60%.

Figs. 1A to 1C show the shape of a textured steel sheet to be a base steel sheet. FIG. 1A is a schematic view when a base material steel plate of a hot-dip plated textured steel plate according to an embodiment of the present invention is viewed from the thickness direction. FIG. 1B is a schematic cross-sectional view when the parent metal plate steel of the hot-dip plated textured steel plate of the same embodiment is viewed on a cutting plane parallel to the thickness direction and the cutting direction, that is, a G-G cross-sectional view of FIG. 1A. FIG. 1C is a schematic cross-sectional view when the parent metal plate steel of the hot-dip plated textured steel plate of the same embodiment is viewed on a cutting plane parallel to the thickness direction and the cutting direction, that is, the F-F cross-sectional view of FIG. 1A. A, B, C, D, E, and H in the figures are as follows. A: The arrangement angle of the convex portions with respect to the rolling direction. B: The length of one convex portion. C: Maximum width of one convex portion. D: The minimum width of one convex portion. E: The arrangement pitch of the convex portions. H: height of the convex portion.

Next, the method for observation and measurement of the hot-dip galvannealed steel sheet according to this embodiment will be described.

For the convex portion and the flat portion of the hot-dip plated textured steel plate, it is only necessary to observe the appearance and cross-section of the hot-dip plated textured steel plate. For example, when the appearance of the hot-dip plated textured steel plate is viewed from the thickness direction, if the appearance is the same as the textured steel plate shown in FIG. 1A, it can be determined that the hot-dip plated textured steel plate has convex portions and flat portions.

To explain in more detail, as long as the cross section corresponding to the GG cross section of FIG. 1A, that is, the cut surface parallel to the cut direction and the thickness direction, and includes the center point (center of gravity) of the convex portion and the long axis of the convex portion The hot-dip galvannealed steel sheet may be observed from above to determine whether the convex portion and the flat portion are present. For example, for the contour curve of the hot-dip galvanized steel sheet appearing in the cross section, a reference line is determined based on the area corresponding to the flat portion of the hot-dip galvanized steel sheet, and the highest peak on the contour curve is calculated. As long as the distance between the vertex and the reference line is 0.5 mm or more, it can be determined that the peak on the contour curve is a convex portion. When the steel sheet is viewed from the thickness direction, if the convex portion is present at more than one per 100 mm ² , it can be determined that the steel sheet is a hot-plated anilox steel sheet.

For the presence of the base metal steel plate, the Ni plated layer, and the molten plated layer in the hot-dip galvanized steel plate, only FE-SEM (Field Emission Scanning Electron Microscope) or TEM (Transmission Electron Microscope) is used. ; Transmission electron microscope) to observe. For example, after cutting the test piece so that the cutting direction is parallel to the thickness direction, the cross-sectional structure of the cutting surface may be observed by using FE-SEM or TEM at a magnification that each layer can enter the observation field. FIG. 2 is a schematic diagram showing a cross-sectional structure of a hot-dip galvanized steel sheet according to this embodiment.

For example, in order to identify each layer in the cross-section structure, EDS (Energy Dispersive X-ray Spectroscopy; energy dispersive X-ray spectrometer) is used to perform line analysis along the thickness direction at a magnification of 20,000 times under the following settings: set the acceleration voltage to 15kV , The irradiation current is 10nA, the beam diameter is approximately less than 100nm, the measurement pitch is 0.025μm, the objective lens aperture is 30μmφ, and the quantitative analysis of the chemical composition of each layer can be performed so that the total of Ni, Fe, and Zn is 100% by mass . In order to remove the measurement noise from the line analysis result, after moving average processing is performed by averaging the data at the five points before and after, the area where the Ni concentration on the scan line is 50% by mass or more may be determined as the Ni plating layer. In addition, based on the Ni plating layer identified on the scan line, the area on the surface side may be determined as the molten plating layer, and the area on the inner side may be determined as the base material steel plate. The molten plating layer is a Zn-based alloy, and the base material steel plate is a Fe-based alloy.

The thickness of the Ni plating layer of the convex portion may be determined by identifying the Ni plating layer of the convex portion on a cross section corresponding to the G-G cross section in FIG. 1A and measuring the film thickness. For example, on the above section, a line analysis is performed along the thickness direction so as to include the highest peak apex on the contour curve of the molten plated textured steel plate, and after the Ni plating layer is identified on the scan line of the online analysis, the scan is calculated The Ni plating layer segment on the line can be used as the Ni plating layer film thickness of the convex portion.

The thickness of the Ni plating layer in the flat portion may be measured in the same manner as described above. For example, on a cross section corresponding to the GG cross section of FIG. 1A, a line analysis is performed in a thickness direction on a flat portion at a position more than 2 mm from the end of the convex portion, and after the Ni plating layer is identified on the scan line of the online analysis, The Ni plating layer segment on the scanning line can be calculated, and the segment can be used as the Ni plating film thickness of the flat portion.

In addition, the thickness of the Ni plating layer of the convex portion and the flat portion may be determined by measuring at least three positions or more and using the average value. In addition, when the thickness of the Ni plating layer of the convex portion and the flat portion is less than 0.3 μm, it is preferable to calculate the film thickness by using TEM instead of using SEM.

Then, based on the thickness of the Ni plating layer of the convex portion and the flat portion obtained as described above, the film thickness ratio of the convex portion to the Ni plating layer of the flat portion (film thickness of the convex portion ÷ film thickness of the flat portion × 100).

The chemical composition and adhesion amount of the hot-dip plating layer may be measured using ICP (Inductive Coupled Plasma) atomic emission spectrometry. For example, a sample with a size of 30 mm × 30 mm is taken from an arbitrary position of the hot-dip plated textured steel sheet, and an inhibitor (for example, IBIT manufactured by Asahi Chemical Industry, model: IBIT 710-K, concentration: 300 ppm, and ppm is mg) / kg) of 10% acetic acid to pickle the plated layer from the sample after pickling, then perform ICP quantitative analysis and calculate the concentration of each element, and then calculate the chemical composition and adhesion amount of the molten plating layer from each element concentration. . It is only necessary to perform the above measurement on a sample taken from at least three positions and use the average value.

The coverage of the hot-dip plating layer with respect to the plate surface may be calculated by observing the hot-dip plating anilox steel sheet from the thickness direction. For example, a sample of 100 mm × 100 mm is taken from an arbitrary position of the hot-dip plated textured steel plate, the sample is observed from the thickness direction, and the area ratio of the unplated area in the sample area may be calculated. The area ratio can be calculated using image analysis software (for example, Mitani Corporation WinROOF). To explain in more detail, the above-mentioned 100 mm × 100 mm sample is divided into sizes that can be measured by EDS or EPMA (Electron Probe Micro-Analyzer; electronic micro-analyzer), and the divided samples are aread by EDS or EPMA. After the Fe distribution map is obtained by analysis, the area ratio of the unplated area (area with Fe concentration of 20% by mass or more) in the sample area may be calculated from the Fe distribution map. In addition, the coverage of the hot-dip plating layer may be calculated based on the area ratio of the unplated area.

Next, a method for manufacturing the hot-dip galvannealed steel sheet according to this embodiment will be described in detail.

The method for manufacturing a hot-dip galvanized steel sheet according to this embodiment includes the following steps: a rolling step that imparts a convex portion and a flat portion to the rolled surface of the steel sheet; and a pre-plating step that applies the steel sheet after the rolling step. Ni pre-plating; a hot-dip plating step that performs hot-dip plating on the steel sheet after the pre-plating step. In the pre-plating step, the rolled surface of the steel sheet and the anode surface are arranged to face each other, and the distance between the convex portion of the rolled surface and the anode is controlled to 40 to 100 mm, and then plating on each side is performed. Ni plating was performed under the conditions of an average amount of 0.5 to 3 g / m ² . In the hot-dip plating step, after the steel sheet is heated, the steel sheet is immersed in the hot-dip plating bath, and continuous hot-dip plating is performed under the condition that the average amount of plating on each side is 60 to 400 g / m ² . The aforementioned molten plating bath contains, by mass%, Al: more than 1.0% and less than 26%, Mg: 0.05 to 10%, Si: 0 to 1.0%, Sn: 0 to 3.0%, and Ca: 0 to 1.0%. And the remainder is composed of Zn and impurities.

In the rolling step, the rolled surface of the steel sheet is provided with a convex portion and a flat portion. The rolling conditions are not particularly limited, as long as the concave shape formed on the active roll is transferred to the surface of the steel sheet during the completion stage of hot rolling, thereby providing convex portions and flat portions to the rolled surface of the steel sheet. . The textured steel sheet that has been shaped by hot rolling is subjected to a pretreatment such as pickling to remove scale and the like. If required, brush grinding can also be performed on the surface of the steel plate.

In the pre-plating step, Ni pre-plating is performed on the textured steel sheet after the pre-treatment. From the standpoint of productivity or the prevention of the incorporation of impurities, the Ni pre-plating is preferably electroplated. For electroplating, a method using a Watts bath, a sulfamic acid bath, or the like can be exemplified.

In the case of the Watt bath method, the preferred Ni plating bath composition is NiSO ₄ · 6H ₂ O: 250 ~ 350g / L, Na ₂ SO ₄ : 50 ~ 150g / L, H ₃ BO ₃ : 30 ~ 50g / L, pH: 2 ~ 3.5, preferred bath temperature is 50 ~ 70 ° C, and preferred cathode current density is 5 ~ 30A / dm ² . Specifically, for example, NiSO ₄ · 6H ₂ O: 340 g / L, Na ₂ SO ₄ : 100 g / L, H ₃ BO ₃ : 45 g / L, pH: 2.5, temperature: 60 ° C, and cathode current density: 20A / dm ² .

In this embodiment, in order to prevent non-plating from occurring during the hot-dip plating step, the amount of Ni deposited in the Ni pre-plating is increased compared to the conventional method. However, in order to cause a loss in the molten plating layer, the corrosion of the steel sheet can be suppressed even after the Ni plating layer is exposed on the convex portion, and excessive Ni precipitation on the convex portion can be avoided.

In an electroplating tank (electrolytic cell), a steel strip is usually used as a cathode, and an anode is disposed so as to face the steel plate surface. The strip surface is parallel to the anode, which is approximately a parallel plate electrode system. If the anilox plate is plated in the electrolytic cell as described above, since the distance between the convex portion of the anilox plate and the anode is very close, it is easy for current to concentrate on the convex portion. In this embodiment, in order to suppress the concentration of current on the convex portions of the textured steel sheet, the distance between the electrodes (the distance between the convex portion of the steel strip surface and the anode) is increased. Conventional conditions have set the inter-electrode distance to be less than 40 mm in order to ensure the uniformity of the current distribution and suppress the power cost. However, in this embodiment, the inter-electrode distance is set to 40 to 100 mm. If the distance between the electrodes is less than 40 mm, a current concentration occurs in the convex portion, and it becomes difficult to control the thickness of the Ni plating layer of the convex portion within a predetermined range. On the other hand, if the distance between the electrodes is more than 100 mm, the power loss due to the resistance of the solution will increase. The lower limit of the distance between the electrodes should be 45mm, more preferably 50mm. The upper limit of the distance between electrodes should be 90mm, more preferably 85mm.

For example, in the conventionally-prepared molten-plated anilox steel sheet having the inter-electrode distance set to less than 40 mm, there is a film thickness ratio of the convex portion to the Ni plating layer of the flat portion (the film thickness of the convex portion ÷ In the case where the film thickness at the flat portion is 100% or more. On the other hand, if the hot-dip galvannealed steel sheet is prepared by setting the inter-electrode distance to 40 mm or more, it is easy to control the film thickness ratio of the Ni plating layer of the convex portion to the flat portion to 400% or less. In addition, as long as the inter-electrode distance is set to 45 mm or more, it is easy to control the film thickness ratio of the Ni plating layer of the convex portion to the flat portion to 300% or less when the hot-dip galvanized steel sheet is made.

In the pre-plating step, the average adhesion amount of Ni pre-plating per one side is set to 0.5 to 3 g / m ² . When the average adhesion amount is less than 0.5 g / m ² , the thickness of the Ni plating layer on the flat portion of the textured steel sheet after the hot-dip plating is less than 0.05 μm, and unplating is liable to occur. If the average adhesion amount is more than 3 g / m ² , the Ni plating layer remaining on the convex portion after the melt plating becomes excessive, and it becomes difficult to make the thickness of the Ni plating layer on the convex portion be 0.4 μm or less.

The Ni adhesion amount of the Ni pre-plating may be measured according to the following procedures a to e before the Zn-based alloy is melt-plated.
Procedure a: 30% by mass of nitric acid was used to dissolve a steel plate subjected to Ni pre-plating (solution A).
Procedure b: A sample was taken from the vicinity of the sample used in procedure a, and the Ni pre-plated layer was removed by grinding or the like, and then dissolved with 30% by mass of nitric acid (dissolving solution B).
Program c: After ICP is used to calculate the amount of Fe and Ni that have been dissolved in the solution B, the ratio of the amount of Fe to the amount of Ni is calculated.
Program d: After calculating the amount of Fe dissolved in the dissolving solution A by ICP, the amount of Ni dissolved from the base material steel plate is calculated based on the ratio calculated in step c.
Program e: After calculating the amount of Ni that has been dissolved in the solution A by ICP, the amount of Ni from the base steel plate calculated in step d is deducted to calculate the amount of Ni from the Ni pre-plated layer. In addition, the amount of Ni from the Ni pre-plated layer was converted into the adhesion amount per unit area.

In addition, although it varies depending on the design of the electrolytic cell, in the continuous plating equipment of the steel strip, the edge may be overplated due to the current concentrated on the widthwise end of the steel sheet. Therefore, when calculating the said average adhesion amount, the width direction edge part (for example, the area of 50 mm from both ends) of a steel strip may be excluded from a measurement object.

In the hot-dip plating step, the anilox steel plate (steel strip) pre-plated with Ni is preheated in a non-oxidizing gas environment, and then passed through the hot-dip plating bath (continuously immersed in the hot-dip plating bath) . The non-oxidizing gas environment is, for example, a mixed gas of nitrogen and hydrogen. The preheating temperature should be in the range of [plating bath temperature + 10 ° C] to [plating bath temperature + 50 ° C]. If the preheating temperature is low, non-plating tends to occur frequently. When preheating, it is advisable to heat the steel plate rapidly at a temperature of 350 ° C or higher for 40 seconds or less. By shortening the time of the steel sheet at 350 ° C. or higher, Ni can be prevented from diffusing into the base material steel sheet, so the amount of Ni pre-plating to prevent the occurrence of non-plating can be sufficiently ensured.

The textured steel sheet preheated in a non-oxidizing gas environment was passed through a molten zinc-based alloy plating bath (immersed in a molten plating bath). The aforementioned molten zinc-based alloy plating bath contained Al: more than 1.0% and Below 26%, Mg: 0.05 ~ 10%, and can contain Si: 0 ~ 1.0%, Sn: 0 ~ 3.0%, and Ca: 0 ~ 1.0% as required. The temperature of the plating bath should be in the range of [melting point of Zn-based alloy molten soup + 20 ° C] to [melting point of Zn-based alloy molten soup + 50 ° C]. In the plating bath of the textured steel plate, it should be wiped after immersion for 1 to 6 seconds, and if necessary, cooled by air water spray or the like.

In the fusion plating step, the average adhesion amount of each side of the fusion plating layer is 60 to 400 g / m ² . When the average adhesion amount is less than 60 g / m ² , the corrosion resistance may be insufficient. If the average adhesion amount is more than 400 g / m ² , excessive dripping of the molten plating layer may cause the plating drooping to be noticeable, thereby deteriorating the appearance.

The chemical composition of the hot-dip plating bath and the adhesion amount of the hot-dip plating bath may be measured using ICP atomic emission spectrometry in the same manner as described above. In addition, the chemical composition of the hot-dip plating bath may not be measured by a sample taken from a hot-dip plating anilox steel sheet, but may be measured by ICP based on a sample taken from a hot-dip plating bath.
[Example 1]

Next, the effects of one aspect of the present invention will be described in more detail by way of examples. However, the conditions in the examples are an example of conditions adopted for confirming the feasibility and effects of the present invention. The present invention is not limited to this. A condition example. As long as the object of the present invention can be achieved without departing from the gist of the present invention, the present invention can adopt various conditions.

A hot-rolled textured steel plate with a thickness of 2.3 mm was used as the plating base plate.
The shape of the textured steel sheet (base material steel sheet) corresponds to FIGS. 1A to 1C. In the figure, A, B, C, D, E, and H are as follows.
A: The arrangement angle of the convex portions with respect to the rolling direction.
B: The length of one convex portion.
C: Maximum width of one convex portion.
D: The minimum width of one convex portion.
E: The arrangement pitch of the convex portions.
H: height of the convex portion.
The anilox steel plate is a hot-rolled Al deoxidized steel with an angle A = 45 °, a width C = 5.1mm, a length B = 25.3mm, a height H = 1.5mm, and a pitch E = 28.6mm. After pickling the anilox steel sheet with the protrusions regularly arranged as described above, Ni pre-plating is performed at various inter-electrode distances to change the average amount of Ni deposited. Tables 1 and 2 show the conditions for Ni pre-plating. The electrolysis efficiency is about 80%. The obtained anilox steel sheet has a cross-sectional structure as shown in FIG. 2.

[Table 1]

The Zn-based alloy hot-dip plating bath shown in Table 2 was used to perform Zn-based alloy hot-dip plating on the steel sheet after Ni pre-plating. Table 2 also describes the temperature of the Zn-based alloy hot-dip plating bath. When performing hot-dip plating of a Zn-based alloy, the steel sheet is heated to a Zn-based alloy plating bath temperature + 30 ° C in a non-oxidizing gas environment (N ₂ -2% H ₂ ) at a temperature increase rate of 10 ° C / sec. After the steel sheet is cooled to a temperature of the plating bath temperature + 10 ° C in the above-mentioned gas environment, the steel sheet is immersed in the plating bath. The immersion time was set to 3 sec, and the amount of hot-melt plating adhered was adjusted by a hot-melt plating adhered amount adjusting device on the sending side of the hot-melt plating apparatus.

[Table 2]

Regarding the obtained hot-dip galvanized steel sheet, according to the above-mentioned observation and measurement methods, it was confirmed that the base material steel sheet, the Ni-plated layer, and the hot-dip plating layer existed in the cross-sectional structure, and that there were protrusions and flat surfaces on the surface unit. In addition, the thickness of the Ni plating layer on the convex portion, the thickness of the Ni plating layer on the flat portion, and the film thickness ratio of the convex portion to the Ni plating layer on the flat portion (film thickness of the convex portion ÷ film on the flat portion) were measured. Thickness × 100), the amount of the molten plating layer, the chemical composition of the molten plating layer, the coverage of the molten plating layer, the amount of Ni deposited in the Ni pre-plating, and the chemical composition of the molten plating bath.

Then, the obtained hot-dip plated textured steel sheet was evaluated according to the following method.

Corrosion test after abrasion A steel plate with a thickness of 5 mm of styrene butadiene rubber is placed on a 100 mm × 50 mm sample, and a 1 kg weight is placed on it and subjected to horizontal reciprocating vibration (stroke: 30mm, number of round trips: 1000 times), which causes abrasion of plating. The abraded steel plate was exposed to the exposed stand at a 45 ° incline with respect to the ground and facing south for the following test for 1 month: in a rainy environment, spread 20ml each time at a frequency of once per week 5% NaCl in water. After 1 month, the area ratio of red rust near the convex portion was evaluated. The evaluation of the area ratio where red rust was generated was measured using WinROOF (image analysis software) manufactured by Mitani Corporation, and the area ratio was calculated. The red rust generation unit extracts the color of red rust by color extraction, and measures the area ratio. When the area ratio where red rust occurs is 5% or more, it is determined that the corrosion resistance after abrasion is poor. In the table, the area ratio where red rust is generated: less than 5% is marked as "Good", and the area ratio where red rust is generated: more than 5% is marked as "Bad".

For the appearance of the plating, a 100 mm square sample was prepared. The plating surface was observed from the thickness direction, and the area ratio of the area of the appearance degradation caused by scum was measured using WinROOF (Image Analysis Software) by Mitani Corporation (referred to as "scum area "). When the scum area ratio was 20% or more, it was determined that the plating appearance was poor. In the table, the scum area ratio: less than 20% is marked as “Good”, and the scum area ratio: more than 20% is marked as “Bad”.

Workability After bending the sample to 90 ° in a V shape, a polyester adhesive tape made by Nitto Denko was attached to the outside of the bending processing section, and after the tape was removed, it was confirmed whether or not the adhesive from the plating layer was attached to the tape. Peel off. When a peeling material from a plating layer adhered to the tape, it was judged that processability was bad. In the table, the case where there is no peeling matter is marked as "Good", and the case where there is peeling matter is marked as "Bad".

Table 3 shows the production results and evaluation results of the produced hot-dip plated textured steel sheet. In addition, the "film thickness ratio of the Ni plating layer" shown in Table 3 means the film thickness ratio of the Ni plating layer of the convex portion with respect to the flat portion (film thickness of the convex portion ÷ film thickness of the flat portion × 100).

[table 3]

In Comparative Example 1, the distance between the electrodes during the Ni pre-plating was not appropriate, so that the film thickness of the Ni plating layer in the convex portion exceeded 0.4 μm, and the film thickness of the Ni plating layer in the planar portion was less than 0.05 μm. As a result, plating failure due to non-plating occurred, and sufficient corrosion resistance could not be obtained in a corrosion test after abrasion.
In Comparative Example 2, the amount of Ni pre-plating was small, and the thickness of the Ni plating layer in the flat portion of the textured steel sheet was insufficient. As a result, plating failure due to non-plating occurred, and sufficient corrosion resistance could not be obtained.
In Comparative Example 3, because the amount of Ni pre-plating was large, the film thickness of the Ni plating layer in the convex portion exceeded 0.4 μm. As a result, sufficient corrosion resistance cannot be obtained in the corrosion test after abrasion.
In Comparative Example 4, since the amount of Al in the hot-dip plating layer of the Zn-based alloy was small, sufficient corrosion resistance could not be obtained and the plating appearance was also poor.
In Comparative Example 5, the Zn-based alloy has a large amount of Al in the hot-dip plating layer, which results in poor plating appearance and inadequate workability. This makes it an industrially less-than-ideal hot-dip galvannealed steel sheet.
In Comparative Example 6, since the amount of Mg in the Zn-based alloy hot-dip plating layer was small, sufficient corrosion resistance could not be obtained.
Comparative Example 7 has a large amount of Mg in the molten plating layer of the Zn-based alloy, which results in poor plating appearance, and is therefore an industrially undesirable molten-plated textured steel sheet.
In Comparative Example 8, because the amount of adhesion of the hot-dip plating layer of the Zn-based alloy was small, sufficient corrosion resistance could not be obtained.
In contrast, in Examples 1 to 10, occurrence of non-plating has been suppressed, and sufficient corrosion resistance is maintained after abrasion. In addition, the appearance and processability of the plating are also satisfied.

INDUSTRIAL APPLICABILITY According to the above aspect of the present invention, it is possible to provide a fusion-plated net in which occurrence of non-plating has been suppressed, and corrosion of the nickel-plated layer has been suppressed when the molten-plated layer is depleted and the Ni plating layer is exposed. Grain steel plate and manufacturing method thereof. Therefore, the industrial availability is high.

1‧‧‧ convex

2‧‧‧ plane department

Fused plating of 3‧‧‧Zn-based alloy

4‧‧‧Ni plating

5‧‧‧ mother steel plate

A‧‧‧ Arrangement angle of convex part with respect to rolling direction

B‧‧‧1 length of convex part

C‧‧‧1 maximum width of 1 convex part

D‧‧‧1 minimum width of convex part

E‧‧‧ Arrangement pitch of convex part

H‧‧‧ convex height

FIG. 1A is a schematic view when a base material steel plate of a hot-dip plated textured steel plate according to an embodiment of the present invention is viewed from the thickness direction.

FIG. 1B is a schematic cross-sectional view when the base material steel plate of the hot-dip plated textured steel plate of the same embodiment is viewed on a cutting plane parallel to the thickness direction and the cutting direction, that is, a G-G cross-sectional view of FIG. 1A.

FIG. 1C is a schematic cross-sectional view when the base material steel plate of the hot-dip plated textured steel plate of the same embodiment is viewed on a cutting plane parallel to the thickness direction and the cutting direction, that is, the F-F cross-sectional view of FIG.

FIG. 2 is a schematic cross-sectional view when the hot-dip galvannealed steel sheet of this embodiment is viewed on a cutting plane parallel to the cutting direction in the thickness direction.

Claims (8)

A fusion plated textured steel plate includes a base material steel plate, a Ni plating layer disposed on a surface of the base material steel plate, and a fusion plating layer disposed on a surface of the Ni plating layer, and has a convex portion and a flat surface on the plate surface. The fused-plated textured steel sheet is characterized in that the film thickness of the Ni plating layer of the convex portion is 0.07 to 0.4 μm per one surface, and the film thickness of the Ni plating layer of the planar portion is one single surface. 0.05 to 0.35 μm; the film thickness of the Ni plating layer of the convex portion is greater than 100% and 400% or less of the film thickness of the Ni plating layer of the planar portion, and the adhesion amount of the molten plating layer 60 to 400 g / m ² per one side, and the chemical composition of the aforementioned molten plating layer contains Al: more than 1.0% and less than 26%, Mg: 0.05 to 10%, Si: 0 to 1.0%, Sn: 0 to 3.0% and Ca: 0 to 1.0%, and the remainder is composed of Zn and impurities. The molten-plated textured steel sheet according to claim 1, wherein the film thickness of the Ni plating layer of the convex portion is greater than 100% and not more than 300% of the film thickness of the Ni plating layer of the planar portion. For example, the hot-dip plated textured steel sheet of claim 1 or claim 2, wherein the aforementioned film thickness of the aforementioned Ni plating layer of the raised portion is 0.07 to 0.3 μm per one side. The molten-plated textured steel sheet according to any one of claim 1 to claim 3, wherein the aforementioned chemical composition of the aforementioned molten plating layer contains Al: 4.0 to 25.0% and Mg: 1.5 to 8.0% by mass%. The fusion-plated textured steel sheet according to any one of claim 1 to claim 4, wherein the aforementioned chemical composition of the aforementioned molten plating layer contains at least one of the following in terms of mass%: Si: 0.05 to 1.0%, Sn: 0.1 to 3.0%, and Ca: 0.01 to 1.0%. In the hot-dip galvanized steel sheet according to any one of claims 1 to 5, when viewed from the thickness direction, the coverage ratio of the aforementioned hot-dip plating layer is 99 to 100% in terms of area% of the plate surface. A method for manufacturing a hot-dip galvanized steel sheet is a method for manufacturing a hot-dip galvanized steel sheet according to any one of claim 1 to claim 6, the manufacturing method is characterized by having the following steps: a rolling step, It provides convex portions and flat portions to the rolled surface of the steel plate; a pre-plating step, which performs Ni pre-plating on the steel plate after the rolling step; a fusion plating step, which The steel plate is subjected to fusion plating; and in the foregoing pre-plating step, the rolled surface of the steel plate and the anode surface are arranged to face each other, and the distance between the protrusions of the rolled surface and the anode is controlled to 40 ~ After 100 mm, Ni plating was performed under the condition that the average amount of plating on each side was 0.5 to 3 g / m ² ; In the aforementioned molten plating step, the steel sheet was heated, and then the steel sheet was immersed in the molten plating bath. The continuous plating is performed under the condition that the average amount of plating on each side is 60 to 400 g / m ^2. The above-mentioned molten plating bath contains Al in mass%: more than 1.0 and less than 26%, Mg : 0.05 to 10%, Si: 0 to 1.0%, Sn: 0 to 3.0%, and Ca: 0 to 1.0%, and the remaining The remainder consists of Zn and impurities. The method for manufacturing a hot-dip galvanized steel sheet according to claim 7, wherein in the pre-plating step, the distance between the electrodes is controlled to 45 to 100 mm.