Specification
Title of invention: Hot-dip striped steel sheet and method for producing the same
Technical field
[0001]
　The present invention relates to a hot-dip striped steel sheet and a method for manufacturing the same.
　The present application claims priority based on Japanese Patent Application No. 2017-178011 filed in Japan on September 15, 2017, the contents of which are incorporated herein by reference.
Background technology
[0002]
　The striped steel plate is a steel plate having continuous non-slip projections (projections) on its surface by rolling. Generally, convex portions having a constant width, a constant length and a constant height are provided at a constant angle and a constant pitch with respect to the rolling direction. Striped steel sheets are usually manufactured by hot rolling. It is used for floor boards and steps of buses and trucks, floorboards of factories, decks of ships, temporary scaffolds and stairs at construction sites, etc.
[0003]
　Conventionally, striped steel sheets are often used as hot-rolled or coated. Especially when rust prevention is required, strips of striped steel sheets have been galvanized by a batch type hot dip galvanizing process using a flux method. However, the batch-type hot-dip galvanizing process has low productivity and the Fe—Zn alloy layer generated in the hot-dip galvanizing step is enlarged, so that the workability of the plating layer is impaired, and cracks and peeling of the plating layer occur. In some cases, it may cause a problem in corrosion resistance.
[0004]
　Continuous hot-dip galvanizing is more productive than batch-type hot-dip galvanizing. Continuous hot-dip galvanizing is generally performed by passing a steel sheet heated to a predetermined temperature in a reducing or non-oxidizing atmosphere through a hot-dip galvanizing bath. Further, since at least about 0.05% of Al is contained in the molten zinc bath, it is possible to suppress the growth of the Fe—Zn alloy layer that impairs the workability of the plating film. In the case of batch type hot dip galvanizing using a general flux method, when Al is contained in a Zn bath, Al decomposes the flux, so that non-plating frequently occurs and plating cannot be performed well.
[0005]
　When applying continuous hot-dip galvanizing to a striped steel sheet, it is necessary to consider the problems caused by the surface shape and the like. For example, Patent Document 1 teaches a continuous hot-dip galvanizing method for striped steel sheets, particularly tension in a plating line and appropriate conditions for gas wiping after hot-dip galvanizing. Currently, continuous hot-dip galvanized strip steel sheets are commercialized.
[0006]
　In recent years, in addition to hot-dip galvanized steel sheets, hot-dip zinc-based alloy-plated steel sheets such as Zn-Al, Zn-Al-Mg, and Zn-Al-Mg-Si have been developed due to the requirement for superior corrosion resistance to galvanizing. It has been commercialized. In response to this, attempts have been made to apply hot-dip zinc-based alloy plating to striped steel sheets.
[0007]
　Patent Document 2 has a quaternary alloy layer of Ni—Al—Zn—Fe having a thickness of 2 μm or less as a first layer on the surface of a striped steel sheet, and the second layer has a weight conversion of 0.1 to 1%. Disclosed is a striped steel sheet having excellent workability and corrosion resistance, which is characterized by having a hot dip plated layer of a Zn-based alloy containing Al. As a specific plating method, Patent Document 2 discloses that a striped steel plate is plated with 0.5 to 2.0 g/m 2 of Ni, then the striped steel plate is heated, and subsequently 0.1 to 1% by weight conversion. A method for manufacturing a striped steel sheet comprising a step of immersing in a molten zinc bath to which Al is added for 1 to 30 seconds.
[0008]
　Patent Document 3 uses a plating bath that is considered to be almost the same as that of Patent Document 2, but defines the structure of a hot-dip coating obtained by the Sendzimir method. Both Patent Documents 2 and 3 are essentially characterized by using a molten zinc-based alloy having an Al concentration of 1% or less. In Patent Documents 2 and 3, since the Al concentration in the plating layer is 1% or less, it is difficult to obtain the barrier anticorrosion effect due to Al, and it is difficult to expect a preferable improvement in the remarkable corrosion resistance of the plating film itself.
[0009]
　Patent Document 4 discloses, in mass%, Al: 4.0 to 20.0%, Mg: 1.0 to 4.0%, and optionally Ti: 0.002 to 0.1% and B: 0.02%. Disclosed is a hot-dip Zn-based plated strip steel sheet excellent in scratch resistance, wear resistance and corrosion resistance, characterized by being coated with a hot-dip coating layer having a composition of 001 to 0.045% and the balance being Zn and inevitable impurities. To do. This plating layer has a large proportion of the ternary eutectic structure of the Al/Zn/ZnMg-based intermetallic compound, and since this ternary eutectic is hard, the Vickers hardness is 120 to 180 Hv, and in addition to corrosion resistance, It is also said to have excellent scratch resistance and wear resistance.
[0010]
　As described above, conventionally, striped steel sheets are often used without plating, zinc plating is applied as necessary, and further, application of zinc-based alloy plating has been attempted instead of zinc plating. .. It should be noted that the pre-plating of the base steel sheet and the zinc-based alloy plating having an Al concentration of more than 1.0% after the Ni pre-plating have not been studied at all.
Prior art documents
Patent literature
[0011]
Patent Document 1: Japanese Unexamined Patent Publication No. 7-11411
Patent Document 2: Japanese Unexamined Patent Publication
No. 6-81170 Japanese Patent Unexamined Publication No. 6-248409 Japanese Patent Publication
No. 11-279732 Publication
Summary of the invention
Problems to be Solved by the Invention
[0012]
　The present inventors initially attempted to perform zinc-based alloy plating with an Al concentration of more than 1.0% on the striped steel sheet for the purpose of further improving the corrosion resistance of the striped steel sheet. However, as a result of examination, it was revealed that non-plating frequently occurs when the striped steel sheet is simply plated with a zinc-based alloy having an Al concentration of more than 1.0%. That is, as in Patent Documents 2 and 3, if the Al concentration of the zinc-based alloy plating is 1.0% or less, the occurrence of non-plating does not become a problem, but as in Patent Document 4, zinc-based alloy plating is performed. It became clear that the occurrence of non-plating becomes a problem if the Al concentration of the above is more than 1.0%.
[0013]
　Specifically, the present inventors initially intend to impart excellent corrosion resistance to a striped steel sheet, and are generally said to have better corrosion resistance than Zn plating. The application of Zn-based alloy plating containing a slight amount of Mg to striped steel sheets was examined. In the process, when the Zn-Al-Mg-based alloy having an Al concentration of more than 1.0% is hot-dipped by the Sendzimir method which is usually adopted as the hot-dip plating method, non-plating frequently occurs. I found out.
[0014]
　The present inventors are apt to cause non-plating in the process of hot-dipping a Zn-based alloy containing Al: more than 1.0% and a small amount of Mg on a striped steel sheet because the Al concentration in the molten Zn increases. It is considered that the wettability between the steel sheet and the molten metal decreases as the temperature rises, and that a specific cause due to the hot rolling history of the striped steel sheet is also related.
[0015]
　With respect to this problem of non-plating, the present inventors have tried to adopt Ni pre-plating which is also adopted in Patent Document 2. As a result of the study, the present inventors can suppress the occurrence of non-plating to some extent by performing zinc-based alloy plating after Ni pre-plating. It has been found that, when plating is performed, the Ni deposition amount in Ni pre-plating needs to be relatively large. However, on the other hand, as a result of the above studies, the present inventors have found that when the Ni deposition amount in the Ni pre-plating is increased, the corrosion resistance is likely to be lowered in the convex portion when the hot-dip striped steel sheet is worn. I found out.
[0016]
　That is, the present inventors have found the following regarding the application of zinc-based alloy plating having an Al concentration of more than 1.0% to striped steel sheets in order to further improve the corrosion resistance.
　(A) Simply plating the striped steel sheet with a zinc-based alloy having an Al concentration of more than 1.0% often causes non-plating.
　(B) In order to apply the zinc-based alloy plating having an Al concentration of more than 1.0% to the striped steel plate, Ni pre-plating is necessary, and the Ni adhesion amount needs to be increased more than in the past.
　(C) However, when the Ni adhesion amount of Ni pre-plating is increased with respect to the striped steel sheet, the corrosion resistance is likely to be lowered at the convex portion when the hot dip strip steel sheet is worn.
[0017]
　The present inventors considered the above phenomenon as follows. For example, when a hot-dip striped steel plate is used for the floor plate or the like, the Ni-plated layer may be exposed because the hot-dip coating layer is greatly worn and damaged at the protrusions. When a Ni-pre-plated steel sheet is plated with molten Zn, molten Zn-Al, or the like, some Ni moves into the plating layer or molten metal due to the reaction with molten metal, but some Ni is It remains on the surface of the steel sheet as a Ni plating layer. Therefore, when the Ni deposition amount of the Ni pre-plating is large, the Ni plating layer remaining on the surface of the steel sheet after the hot dipping becomes thick.
[0018]
　Normally, the natural immersion potential becomes noble to base in the order of Ni, Fe, and the plating layer, but the natural immersion potential of a relatively thin Ni plating layer is a mixed potential of Ni and Fe. In hot-dip galvanizing of a Ni-pre-plated Zn-based alloy, if the hot-dip Zn-based alloy hot-dip layer is worn and the Ni-plated layer is exposed, Galvanic corrosion occurs between the exposed portion and the vicinity of the exposed portion. For example, in a hot-dip striped steel sheet, Galvanic corrosion occurs between the Ni plating layer exposed at the convex portion and the hot-dip coating 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 approaches the potential of Fe, and Galvanic corrosion between the Ni plating layer and the hot dip coating layer occurs. The speed is not great. On the contrary, when the Ni plating layer is thick, the natural immersion potential of the Ni plating layer is substantially close to the Ni potential even though it is a mixed potential, so that the Galvanic corrosion rate between the Ni plating layer and the hot dip coating layer is high. Will grow. As a result, the hot-dip layer is easily corroded and worn.
[0019]
　Hereinafter, in order to prevent confusion, in the present specification, unless otherwise specified, when a “Ni plating layer” or “Ni plating” is used to represent a plating layer, the Ni coating remaining after hot dipping is used. It means a layer, and "Ni pre-plating layer" and "Ni pre-plating" mean the Ni coating layer existing before the hot dipping process. Further, in the following description of the present specification, when expressions such as “hot-dip plating of Zn-based alloy” and “hot-dip plating” are used, it means “hot-dip plating of Zn—Al—Mg-based alloy”.
[0020]
　The present invention relates to a striped steel sheet obtained by hot-dip coating a Zn—Al—Mg-based alloy containing more than 1.0% Al, with almost no non-plating and a Zn-based alloy at the convex portions of the striped steel sheet. It is an object of the present invention to provide a hot-dip striped steel sheet that exhibits excellent corrosion resistance even when the hot-dip galvanizing wears out (corrosion or wear), and a method for producing the same. Incidentally, in the present invention, which is a general characteristic required for hot-dip striped steel sheet, while satisfying the plating appearance and workability, etc., hot-dip galvanizing that can both suppress the above-mentioned non-plating and corrosion resistance after wear An object of the present invention is to provide a striped steel sheet and a method for manufacturing the striped steel sheet.
Means for solving the problem
[0021]
　When the present inventors attempt hot-dip plating of a Zn-Al-Mg-based alloy containing more than 1.0% of Al on a striped steel plate pre-plated with Ni, the Ni adhesion is relatively large from the viewpoint of preventing non-plating. Although the amount is required, from the viewpoint of ensuring the corrosion resistance on the convex portions of the striped steel sheet, it was considered that at least the Ni adhesion amount on the convex portions needs to be suppressed to a certain value or less.
[0022]
　When performing Ni pre-plating on a steel strip, electroplating is usually adopted. Although it is possible to deposit Ni on a steel strip by an electroless method, it is not preferable because the productivity is poor and a large amount of elements other than Ni are mixed in the deposited film. When electroplating a general steel strip, the anode is usually placed so as to face the steel strip surface, which is the cathode, and the distance between the steel strip and the anode is made as small as possible for electrolysis. The power cost is suppressed while ensuring the uniformity of the current distribution.
[0023]
　However, when electroplating is performed on the striped steel sheet, the convex portion of the striped steel sheet is closer to the anode than the flat portion of the striped steel sheet, so that the Ni deposition amount is large in the convex portion of the striped steel sheet. That is, when a striped steel sheet is electroplated in an ordinary electrolytic bath under conventional conditions and Ni pre-plating is performed, the amount of Ni deposited on the convex portion becomes very large, and as a result, the hot-dip coating layer of the hot-dip striped steel sheet is formed. It is feared that the Galvanic corrosion will occur significantly in the convex portion when the material is worn.
[0024]
　The present inventors have set a lower limit of the thickness of a Ni pre-plated layer required for preventing non-plating in a hot-dip striped steel sheet of a Zn—Al—Mg-based alloy containing more than 1.0% Al. , By determining the upper limit of the thickness of the Ni plating layer that should be limited in order to secure the corrosion resistance in the convex portion, and by defining the thickness ratio of the Ni plating layer in the convex portion and the flat portion, We have found that we can overcome the challenges.
[0025]
　The gist of the present invention is as follows.
(1) A hot-dip striped steel sheet according to an aspect of the present invention includes a base material steel sheet, a Ni plating layer provided on the surface of the base material steel sheet, and a hot-dip coating layer provided on the surface of the Ni plating layer. A hot-dip striped steel sheet having a convex portion and a flat portion on the plate surface, wherein the thickness of the Ni plating layer on the convex portion is 0.07 to 0.4 μm per surface, and the Ni plating layer on the flat portion is The film thickness is 0.05 to 0.35 μm per one side, the film thickness of the Ni plating layer on the convex portion is more than 100% and 400% or less with respect to the film thickness of the Ni plating layer on the flat portion, and hot dip coating is performed. The adhesion amount of the layer is 60 to 400 g/m 2 on one side, and the hot-dip coating layer has a chemical composition of mass%: Al: more than 1.0% and 26% or less, Mg: 0.05 to 10%, Si: It contains 0 to 1.0%, Sn: 0 to 3.0%, Ca: 0 to 1.0%, and the balance is Zn and impurities.
(2) In the hot-dip striped steel sheet according to (1) above, even if the thickness of the Ni plating layer on the convex portion is more than 100% and 300% or less of the thickness of the Ni plating layer on the flat portion. Good.
(3) In the hot-dip striped steel sheet described in (1) or (2) above, the thickness of the Ni plating layer on the convex portion may be 0.07 to 0.3 μm per surface.
(4) In the hot-dip striped steel sheet according to any one of (1) to (3) above, the hot-dip coating layer has a chemical composition of mass%, Al: 4.0 to 25.0%, and Mg. : 1.5 to 8.0% may be included.
(5) In the hot-dip striped steel sheet according to any one of the above (1) to (4), the hot-dip coating layer has a chemical composition of mass%, Si: 0.05 to 1.0%, Sn. : 0.1 to 3.0% and Ca: 0.01 to 1.0%.
(6) In the hot-dip striped steel sheet according to any one of (1) to (5) above, when viewed from the thickness direction, the coverage of the hot-dip coating layer is 99% in area% with respect to the plate surface. It may be 100%.
(7) A method for producing a hot-dip striped steel sheet according to an aspect of the present invention is a method for producing the striped steel sheet according to any one of (1) to (6) above, wherein Pre-plating includes a rolling step of providing a convex portion and a flat portion, a pre-plating step of performing Ni pre-plating on the steel sheet that has undergone the rolling step, and a hot-dip plating step of performing hot-dip plating on the steel sheet that has undergone the pre-plating step. In the process, the rolled surface and the anode surface of the steel sheet are arranged so as to face each other, the distance between the protrusions of the rolled surface and the anode is controlled to 40 to 100 mm, and the amount of plating adhered per surface is 0.5 on average. Electric Ni plating is performed under the condition of up to 3 g/m 2, and in the hot dip plating step, the steel sheet is heated and, in mass %, Al: more than 1.0 and 26% or less, Mg: 0.05 to 10%, Si: A steel sheet is dipped in a hot dip plating bath containing 0 to 1.0%, Sn: 0 to 3.0%, Ca: 0 to 1.0%, and the balance Zn and impurities. Continuous hot-dip plating is performed under the condition that the average is 60 to 400 g/m 2 .
(8) In the method for manufacturing a hot-dip striped steel sheet according to (7) above, the inter-electrode distance may be controlled to 45 to 100 mm in the pre-plating step.
Effect of the invention
[0026]
　According to the above aspect of the present invention, since the hot-dip plated layer contains more than 1.0% Al, excellent corrosion resistance is obtained, and in addition, since the thickness of the Ni plated layer is controlled, the Generation can be suppressed, and corrosion when the hot-dip plated layer is worn and the Ni plated layer is exposed can also be suppressed. As a result, as a hot-dip striped steel sheet, it is possible to reduce the life cycle costs of floor boards, floor boards, structures, and the like.
Brief description of the drawings
[0027]
FIG. 1A is a schematic view of a base material steel sheet of a hot-dip striped steel sheet according to an embodiment of the present invention when viewed from the thickness direction.
FIG. 1B is a schematic cross-sectional view of the base material steel sheet of the hot-dip striped steel sheet according to the same embodiment as seen in a cross section in which the thickness direction and the cutting direction are parallel to each other, taken along the line GG in FIG. 1A. It is a figure.
FIG. 1C is a schematic cross-sectional view of the base material steel sheet of the hot-dip striped steel sheet according to the same embodiment as seen from a cut surface in which the thickness direction and the cutting direction are parallel, and FIG. It is a figure.
FIG. 2 is a schematic cross-sectional view of the hot-dip striped steel sheet according to the embodiment as seen from a cut surface in which the thickness direction and the cutting direction are parallel to each other.
MODE FOR CARRYING OUT THE INVENTION
[0028]
　Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the configuration disclosed in the present embodiment, and various modifications can be made without departing from the spirit of the present invention. The lower limit and the upper limit are included in the numerical limit range described below. Numerical values ​​indicating “above” or “less than” are not included in the numerical range.
[0029]
　The hot-dip striped steel sheet according to the present embodiment is a base material steel sheet, a Ni plating layer provided on the surface of the base material steel sheet, and a Zn-based (Zn-Al-Mg-based) alloy provided on the surface of the Ni plating layer. Of the hot-dip galvanized layer, and has a convex portion and a flat portion on the plate surface. In addition, the thickness of the Ni plating layer on the convex portion is 0.07 to 0.4 μm per side, the thickness of the Ni plating layer on the flat portion is 0.05 to 0.35 μm per side, and The film thickness of the Ni plating layer is more than 100% and 400% or less with respect to the film thickness of the Ni plating layer on the flat surface portion. Further, the amount of the hot-dip coating layer deposited is 60 to 400 g/m 2 on one side , and the hot-dip coating layer has a chemical composition of, in mass %, Al: more than 1.0% and 26% or less, Mg: 0.05 to 10%, Si: 0 to 1.0%, Sn: 0 to 3.0%, Ca: 0 to 1.0%, with the balance being Zn and impurities.
[0030]
　In addition, a thin intermetallic compound layer may be formed on the Ni plating layer side of the hot-dip plating layer based on the reaction between the molten metal (hot-dip bath of Zn-based alloy) and the Ni pre-plated steel sheet, and its composition Changes depending on the composition of the Zn-based alloy hot-dip bath. In the present embodiment, the term “Zn-based alloy hot-dip layer” is used to include this intermetallic compound layer.
[0031]
　First, the hot-dip coating layer of the hot-dip striped steel sheet according to this embodiment will be described in detail.
[0032]
　The hot-dip plated layer is a Zn-based alloy and contains, as a chemical composition, by mass%, Al: more than 1.0% and 26% or less, and Mg: 0.05 to 10%.
[0033]
　Al (aluminum) is important for ensuring the corrosion resistance of the hot-dip plated layer, and also prevents the oxidation of the molten metal and the generation of Fe-Zn-based dross. Therefore, the Al concentration of the hot-dip plated layer is set to exceed 1.0%. On the other hand, when the Al concentration of the plating bath increases, the melting point rises, so it is necessary to raise the temperature of the molten metal, and when the Al concentration exceeds 26%, it is difficult to ensure the beautiful surface properties of the plating layer. Therefore, the workability is likely to deteriorate. Therefore, the Al concentration of the hot-dip plated layer is 26% or less. From the viewpoint of corrosion resistance, the Al concentration of the hot-dip plated layer is preferably 4.0% or more. From the viewpoint of workability, the Al concentration of the hot-dip plated layer is preferably 25.0% or less, more preferably 21.0% or less.
[0034]
　Mg (magnesium) forms a stable corrosion product in a corrosive environment, forms a barrier layer against corrosion, and makes the corrosion resistance more excellent. If the Mg concentration is less than 0.05%, this effect is poor, so the Mg concentration in the hot-dip plated layer is set to 0.05% or more. On the other hand, the oxidation of the molten metal is promoted as the concentration of Mg in the molten metal increases. Therefore, the Mg concentration in the hot-dip plated layer is set to 10% or less. Further, if the Mg concentration exceeds 10%, it becomes difficult to secure the beautiful surface properties of the plating layer, including the effect of increasing the amount of oxide-based dross generated. The preferable lower limit of the Mg concentration is 0.5%, more preferably 1%, further preferably 1.5%, and further preferably 2.0%. The preferable upper limit of the Mg concentration is 8.5%, more preferably 8.0%, and further preferably 6.0%.
[0035]
　The hot-dip coating layer of the hot-dip striped steel sheet according to the present embodiment contains Al and Mg which are the basic elements described above as a chemical composition, and the balance is Zn and impurities. For example, in the hot-dip plated layer, the Zn concentration is 64 to 98.95% by mass. The hot-dip plated layer contains, as a selective element, 1.0% or less of Si, 3.0% or less of Sn, and 1.0% or less of Ca as selective elements, instead of a part of the remaining Zn. You may let me.
[0036]
　Si (silicon) suppresses the growth of the interface alloy phase formed at the interface with the base steel sheet, contributes to the improvement of workability, suppresses the oxidation of Mg, and forms Mg and Mg 2 Si. This also contributes to the improvement of corrosion resistance. Therefore, the Si concentration of the hot-dip plated layer may be 0 to 1.0%. When it is desired to obtain the above effect of Si, Si is contained in an amount of 0.05% or more, preferably 0.1% or more. On the other hand, even if the Si concentration exceeds 1.0%, the above effect is saturated. The preferable upper limit of the Si concentration is 0.6%.
[0037]
　Sn (tin) forms Mg and Mg 2 Sn, and also contributes to the improvement of corrosion resistance, particularly end face corrosion resistance. Therefore, the Sn concentration of the hot-dip plated layer may be 0 to 3.0%. In order to obtain the above effect of Sn preferably, Sn is contained by 0.1% or more, preferably 0.3% or more. On the other hand, when the Sn concentration exceeds 3.0%, the corrosion resistance tends to deteriorate, particularly the corrosion resistance of the flat portion. The preferable upper limit of the Sn concentration is 2.4%.
[0038]
　Ca (calcium) is effective in preventing the oxidation of the plating bath surface. The molten metal of Zn—Al—Mg-based alloy tends to be oxidized more easily than the case where Mg is not contained. By containing Ca, the oxidation of the plating bath surface can be preferably suppressed. Therefore, the Ca concentration of the hot dip plated layer may be 0 to 1.0%. The Ca concentration is preferably 0.01% or more, more preferably 0.1% or more. On the other hand, when the Ca concentration exceeds 1.0%, the precipitation of Ca-based intermetallic compounds is increased, and the corrosion resistance is lowered, and in particular, the flat portion may be deteriorated. The preferable upper limit of the Ca concentration is 0.7%.
[0039]
　Regarding the chemical composition of the hot-dip plated layer, the balance of the basic element and the selective element described above consists of Zn and impurities. The "impurity" refers to a substance mixed from the raw material, the manufacturing environment, or the like. For example, in the hot-dip plated layer of the hot-dip striped steel sheet according to the present embodiment, Ni, Fe, etc. are dissolved from the steel sheet surface into the plating bath to become impurities in the Zn-based alloy. For example, the hot-dip plated layer may include Ni derived from the Ni pre-plated layer, and the Ni concentration may be 0.01 to 0.3% by mass. In the hot-dip coating layer of the hot-dip striped steel sheet according to the present embodiment, impurities are allowed as long as the target characteristics are not impaired.
[0040]
　A Ni—Al based intermetallic compound layer may be formed at the interface between the hot dip plated layer and the Ni plated layer. In the present embodiment, this intermetallic compound layer is considered to be a part of the hot dip plated layer.
[0041]
　In addition, in the present embodiment, the average amount of the hot-dip coating layer is 60 g/m 2 or more per side . The average adhesion amount means the average adhesion amount including the convex portion and the flat surface portion of the hot-dip striped steel sheet. That is, it means the amount of adhesion per projected area in which the protrusion of the hot-dip striped steel sheet is ignored. If the average amount of adhesion of the hot dip plated layer is less than 60 g/m 2 , the corrosion resistance becomes insufficient. The upper limit of the average coating amount of the hot dip coating layer is not necessarily limited, but since the excessive coating of the hot dip coating layer causes significant plating dripping and impairs the appearance, the average coating amount of the hot dip coating layer is 400 g/m 2 or less per side. Preferably.
[0042]
　Further, in this embodiment, when the hot-dip striped steel sheet is viewed from the thickness direction, it is preferable that the coverage of the hot-dip plated layer is 99% to 100% in area% with respect to the plate surface. When the coverage of the hot-dip plated layer is 99% or more in area %, it can be judged that the occurrence of non-plating can be preferably suppressed.
[0043]
　Next, the Ni plating layer of the hot-dip striped steel sheet according to this embodiment will be described in detail.
[0044]
　The Ni plating layer is a Ni pre-plating layer previously formed on the surface of the base material steel sheet to prevent non-plating in the hot dip coating process, and remains between the base material steel sheet and the hot dip coating layer after hot dipping. Is.
[0045]
　The Ni-plated layer is, for example, a region where the contrast observed between the base steel sheet and the hot-dip plated layer is light when the cross-section of the hot-dip striped steel sheet is observed by a backscattered electron image of SEM (Scanning Electron Microscope). It is the range displayed in white). In the present embodiment, the intermetallic compound layer containing Ni that may be formed at the interface between the Ni plating layer and the base material steel sheet, and the Ni that may be formed at the interface between the Ni plating layer and the hot dip coating layer are used. The intermetallic compound layer containing is not included in the Ni plating layer.
[0046]
　The Ni plating layer contains Ni as a chemical composition, and the balance consists of impurities. For example, the Ni concentration of the Ni plating layer is preferably 50 to 100% by mass. The "impurity" refers to a substance mixed from the raw material, the manufacturing environment, or the like. For example, the Ni plating layer of the hot-dip striped steel sheet according to this embodiment contains impurities due to diffusion of Fe from the base steel sheet.
[0047]
　In the present embodiment, the film thickness of the Ni plating layer of the convex portion of the hot-dip striped steel sheet is 0.4 μm or less on average per one surface when viewed on the cut surface where the thickness direction and the cutting direction are parallel to each other. is necessary. If this film thickness exceeds 0.4 μm, the hot-dip galvanized layer of the Zn-based alloy is worn at the protrusions and the corrosion resistance when the Ni-plated layer is exposed is reduced. The thickness of the Ni plating layer on the convex portion is preferably 0.3 μm or less. On the other hand, the lower limit of the film thickness of the Ni plating layer of the convex portion is 0.07 μm or more on average per one surface. If this film thickness is less than 0.07 μm, non-plating occurs on the convex portions. The film thickness of the Ni plating layer on the convex portion is preferably 0.1 μm or more.
[0048]
　Further, in the present embodiment, the thickness of the Ni plating layer on the flat surface portion of the hot-dip striped steel sheet is 0.05 μm or more on average per one surface when viewed on the cut surface where the thickness direction and the cutting direction are parallel to each other. It is necessary. When this film thickness is less than 0.05 μm, non-plating occurs on the flat surface portion. On the other hand, the upper limit of the film thickness of the Ni plating layer on the flat surface portion is 0.35 μm or less on average per one surface. If this film thickness exceeds 0.35 μm, the effect of improving the plating adhesion on the flat surface is saturated, which is not economical.
[0049]
　In addition, in the present embodiment, when viewed from a cut surface in which the thickness direction and the cutting direction are parallel to each other, the film thickness of the Ni plating layer of the convex portion is 100% with respect to the film thickness of the Ni plating layer of the flat portion. % And 400% or less is required.
[0050]
　As described above, under the conventional electroplating conditions, in the case of a striped steel sheet, Ni is preferentially attached to the convex portion instead of the flat portion. For example, when the distance between the convex portion of the striped steel plate and the anode is set to less than 40 mm as in the conventional art, the film thickness of the Ni plating layer of the convex portion is equal to the film thickness of the Ni plating layer of the flat portion. However, it was confirmed that it may be 2000% or more.
[0051]
　However, as described above, the present inventors do not increase the film thickness of the Ni plating layer of the convex portion so much in order to enhance the corrosion resistance of the convex portion after wear, while suppressing the non-plating in the flat portion. In order to achieve this, it was found that it is necessary to secure a certain thickness of the Ni plating layer on the flat surface portion. That is, in the present embodiment, the thickness ratio of the Ni plating layer of the convex portion to the flat portion (thickness of the convex portion/thickness of the flat portion×100) is made smaller than that of the conventional hot-dip striped steel sheet.
[0052]
　When the thickness ratio of the Ni plating layer of the convex portion to the flat portion (thickness of the convex portion/thickness of the flat portion×100) exceeds 400%, suppression of non-plating on the flat portion and corrosion resistance after wear on the convex portion Since it becomes difficult to satisfy both of these conditions, the thickness ratio of the Ni plating layer of the convex portion to the flat surface portion is set to 400% or less in the present embodiment. The film thickness ratio of the Ni plating layer of the convex portion to the flat surface portion is preferably 350% or less, more preferably 300% or less, and most preferably 250% or less.
[0053]
　On the other hand, making the thickness of the Ni plating layer of the convex portion smaller than the thickness of the Ni plating layer of the flat surface portion or making the thickness of the Ni plating layer the same for the convex portion and the flat surface portion is a striped steel sheet. Due to the shape of, it is practically difficult to electroplat. Therefore, in this embodiment, the film thickness ratio of the Ni plating layer of the convex portion to the flat portion is set to more than 100%.
[0054]
　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, it is possible to obtain an effect that both non-plating suppression on the flat portion and corrosion resistance after wear on the convex portion can be achieved. In addition to this, it is possible to increase the Ni adhesion amount in the necessary area (flat surface portion) and reduce the Ni adhesion amount in the unnecessary area (convex portion), so that it is possible to effectively utilize Ni, which is a finite resource.
[0055]
　Next, the base steel sheet of the hot-dip striped steel sheet according to the present embodiment will be described in detail.
[0056]
　In this embodiment, the base material steel plate (original plate to be plated) is a striped steel plate. The striped steel plate is usually provided with a convex shape by hot rolling. The steel type of the base material steel sheet is not particularly limited, but a steel type corresponding to the general structural rolled steel material specified in JIS G3101 is usually used. The convex shape of the striped steel sheet can be imparted by, for example, transferring the concave shape formed on the operating roll to the steel sheet surface in the finishing stage of hot rolling. In the present embodiment, the stripe height (height of the convex portion) and the occupancy rate of the stripe portion (convex portion) are not necessarily limited, but in consideration of slip prevention as a floor plate and usability in particular. The stripe height is 0.5 to 3.5 mm, and the area occupation ratio of the stripe portion is 15 to 60%.
[0057]
　1A to 1C show the shapes of striped steel plates that are base steel plates. FIG. 1A is a schematic view of a base material steel sheet of a hot-dip striped steel sheet according to an embodiment of the present invention when viewed from the thickness direction. FIG. 1B is a schematic cross-sectional view of the base material steel sheet of the hot-dip striped steel sheet according to the same embodiment as seen in a cross section in which the thickness direction and the cutting direction are parallel to each other, taken along the line GG in FIG. 1A. It is a figure. FIG. 1C is a schematic cross-sectional view of the base material steel sheet of the hot-dip striped steel sheet according to the same embodiment as seen from a cross section in which the thickness direction and the cutting direction are parallel to each other, and is a FF cross section of FIG. 1A. It is a figure. A, B, C, D, E, and H in these figures are as follows, respectively. A: The array angle of the convex portions with respect to the rolling direction. B: Length of one convex portion. C: Maximum width for one convex portion. D: Minimum width for one convex portion. E: Array pitch of convex portions. H: Height of convex portion.
[0058]
　Next, with respect to the hot-dip striped steel sheet according to this embodiment, an observation method and a measurement method will be described.
[0059]
　For the projections and flat portions of the hot-dip striped steel sheet, the appearance and cross section of the hot-dip striped steel sheet may be observed. For example, when the appearance of the hot-dip striped steel sheet is observed from the thickness direction and the appearance is equivalent to that of the striped steel sheet shown in FIG. 1A, it can be determined that the hot-dip striped steel sheet has a convex portion and a flat surface portion.
[0060]
　More specifically, the hot-dip striped steel sheet is a cross section corresponding to the GG cross section of FIG. 1A, that is, a cutting plane whose cutting direction is parallel to the thickness direction, and the center point (center of gravity) of the convex portion. It may be determined by observing the cut surface including the long axis of the convex portion and the convex portion and the flat portion. For example, with respect to the contour curve of the hot-dip striped steel sheet appearing in this cross section, a reference line is determined based on the area corresponding to the flat surface portion of the hot-dip striped steel sheet, and the peak of the highest peak on this reference line and the contour curve If the distance is 0.5 mm or more, it may be determined that the peak on the contour curve is a convex portion. When one or more protrusions are present per 100 mm 2 when the steel sheet is observed from the thickness direction, it may be determined that the steel sheet is a hot-dip striped steel sheet.
[0061]
　Whether or not the base material steel plate, the Ni plating layer, and the hot-dip plating layer are present in the hot-dip striped steel plate may be observed by FE-SEM (Field Emission Scanning Electron Microscope) or TEM (Transmission Electron Microscope). For example, a test piece may be cut out so that the cutting direction is parallel to the thickness direction, and the cross-sectional structure of the cut surface may be observed by FE-SEM or TEM at a magnification that allows each layer to be included in the observation visual field. FIG. 2 shows a schematic diagram of the cross-sectional structure of the hot-dip striped steel sheet according to the present embodiment.
[0062]
　For example, in order to identify each layer in the cross-sectional structure, an EDS (Energy Dispersive X-ray Spectroscopy) is used, and an acceleration voltage is 15 kV, an irradiation current is 10 nA, and a beam diameter is 10 nA along the thickness direction at a magnification of 20000. A line analysis may be performed with a measurement pitch of about 100 nm, a measurement pitch of 0.025 μm, and an aperture diameter of the objective lens of 30 μmφ, and the chemical composition of each layer may be quantitatively analyzed with the total of Ni, Fe, and Zn being 100% by mass. In order to remove measurement noise from the result of this line analysis, a moving average process of averaging the data of 5 points before and after was performed, and then a region where the Ni concentration was 50% by mass or more on the scanning line was formed by the Ni plating layer. You can judge that there is. Further, with the above Ni plating layer identified on the scanning line as a reference, the area on the surface side may be determined to be the hot-dip coating layer, and the area on the inner side may be determined to be the base steel sheet. The hot-dip plated layer is a Zn-based alloy and the base steel sheet is an Fe-based alloy.
[0063]
　Regarding the film thickness of the Ni plating layer of the convex portion, the Ni plating layer of the convex portion may be identified on the cross section corresponding to the GG cross section of FIG. 1A, and the film thickness may be measured. For example, in the above cross section, a line analysis is performed along the thickness direction so as to include the highest peaks on the contour curve of the hot-dip striped steel sheet, and the Ni plating layer is identified on the scanning line of the line analysis. The line segment of the Ni plating layer on the scanning line may be obtained and this line segment may be adopted as the film thickness of the Ni plating layer of the convex portion.
[0064]
　The thickness of the Ni plating layer on the flat surface portion may be measured in the same manner as above. For example, in a cross section corresponding to the GG cross section of FIG. 1A, line analysis is performed along the thickness direction on a flat portion at a position 2 mm or more from the end of the convex portion, and Ni plating is performed on the scanning line of the line analysis. The layer may be identified, the line segment of the Ni plating layer on the scanning line may be obtained, and this line segment may be adopted as the film thickness of the Ni plating layer on the flat surface portion.
[0065]
　The thicknesses of the Ni plating layer on the convex portion and the flat surface portion may be measured at at least three points and the average value thereof may be adopted. Further, when the film thickness of the Ni plating layer on the convex portion and the flat surface portion is less than 0.3 μm, it is preferable to obtain the film thickness by TEM instead of SEM.
[0066]
　Further, based on the film thickness of the Ni plating layer of the convex portion and the flat surface portion obtained above, the film thickness ratio of the Ni plating layer of the convex portion to the flat surface portion (thickness of the convex portion/thickness of the flat portion×100) Should be calculated.
[0067]
　The chemical composition and adhesion amount of the hot-dip plated layer may be measured using ICP (Inductive Coupled Plasma) emission spectroscopy. For example, a sample having a size of 30 mm×30 mm is taken from an arbitrary portion of a hot-dip striped steel sheet, and an inhibitor (eg, Asahi Kagaku Kogyo Ibit, model number: Ibit 710-K, concentration: 300 ppm, where ppm is (mg/kg) 10% hydrochloric acid added, only the plating layer is pickled and peeled off, ICP quantitative analysis is performed to find the concentration of each element, and the chemical composition and the amount of adhesion of the hot-dip coating layer are determined from the concentration of each element. Just ask. The above measurement may be performed on the samples collected from at least three locations, and the average value may be adopted.
[0068]
　The coverage of the hot-dip coating layer on the plate surface may be obtained by observing the hot-dip striped steel sheet in the thickness direction. For example, a 100 mm×100 mm sample may be sampled from any location on the hot-dip striped steel sheet, the sample may be observed in the thickness direction, and the area ratio of the unplated region in the sample area may be determined. The area ratio may be obtained using image analysis software (for example, WinROOF manufactured by Mitani Corporation). More specifically, the above 100 mm×100 mm sample is divided into sizes that can be measured by EDS or EPMA (Electron Probe Micro-Analyzer), and surface analysis is performed using EDS or EPMA for each divided sample. The Fe distribution maps may be obtained, and the area ratio of the unplated region (region where the Fe concentration is 20% by mass or more) in the sample area may be obtained from these Fe distribution maps. The coverage of the hot-dip plated layer may be calculated based on the area ratio of the non-plated area.
[0069]
　Next, a method for manufacturing the hot-dip striped steel sheet according to this embodiment will be described in detail.
[0070]
　The method for manufacturing a hot-dip striped steel sheet according to the present embodiment includes a rolling step of providing convex portions and flat portions on a rolled surface of the steel sheet, a pre-plating step of performing Ni pre-plating on the steel sheet that has undergone the rolling step, and a pre-plating step. A hot-dip plating step of performing hot-dip plating on the steel plate that has gone through the steps. In the pre-plating step, the rolled surface and the anode surface of the steel sheet are arranged so as to face each other, the distance between the protrusions on the rolled surface and the anode is controlled to 40 to 100 mm, and the amount of plating adhered per surface is 0 on average. Electrical Ni plating is performed under the condition of 0.5 to 3 g/m 2 . Further, in the hot dip plating step, the steel sheet is heated and, in mass %, Al: more than 1.0 and 26% or less, Mg: 0.05 to 10%, Si: 0 to 1.0%, Sn: 0 to 3. 0%, Ca: 0-1.0%, the rest is immersed in a hot-dip galvanizing bath consisting of Zn and impurities, under the condition that the coating weight per surface is 60-400 g/m 2 on average. Perform continuous hot dip plating.
[0071]
　In the rolling process, convex portions and flat portions are provided on the rolled surface of the steel sheet. The rolling conditions are not particularly limited, but the convex shape and the flat surface portion may be provided on the rolled surface of the steel sheet by transferring the concave shape formed on the working roll to the steel sheet surface in the finishing stage of hot rolling. The striped steel sheet having the shape imparted by hot rolling is subjected to pretreatment such as pickling to remove scale and the like. If necessary, the surface of the steel sheet may be brush-ground or the like.
[0072]
　In the pre-plating step, the pre-treated striped steel sheet is subjected to Ni pre-plating. As the Ni pre-plating, it is desirable to use electroplating from the viewpoint of productivity and the suppression of mixing of impurity elements. For electroplating, a method using a Watt bath, a sulfamic acid bath or the like is exemplified.
[0073]
　As long as it is a method of using a Watts bath, preferably Ni plating bath composition, NiSO 4 · 6H 2 O: 250 ~ 350 g / L, Na 2 SO 4 : 50 ~ 150 g / L, H 3 BO 3 : 30 ~ 50 g / L PH: 2 to 3.5, preferred bath temperature is 50 to 70° C., preferred cathode current density is 5 to 30 A/dm 2 . Specifically, 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., cathode current density: 20 A/dm 2 .
[0074]
　In the present embodiment, in order to prevent the occurrence of non-plating in the hot dip plating step, the Ni deposition amount in the Ni pre-plating is increased as compared with the conventional method. However, excessive Ni precipitation in the convex portions is avoided so that the corrosion of the steel sheet is suppressed even if the hot-dip galvanized layer is worn and the Ni plated layers are exposed at the convex portions.
[0075]
　In an electroplating bath (electrolysis bath), a steel strip is usually used as a cathode, and an anode is arranged so as to face a steel plate surface. The steel strip surface and the anode are parallel, and are approximated by a parallel plate electrode system. When the striped steel sheet is electroplated in such an electrolytic bath, the convex portion of the striped steel sheet and the anode are close to each other in distance, so that current concentration is likely to occur in the convex portion. In the present embodiment, in order to suppress the current concentration on the convex portions of the striped steel sheet, the distance between the electrodes (the distance between the convex portion of the steel strip surface and the anode) is increased. Under the conventional conditions, the distance between the electrodes is set to be less than 40 mm in order to suppress the power cost while ensuring the uniformity of the current distribution, but in the present embodiment, the distance between the electrodes is set to 40 to 100 mm. If the distance between the electrodes is less than 40 mm, 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 exceeds 100 mm, the power loss due to the liquid resistance increases. The lower limit of the inter-electrode distance is preferably 45 mm, more preferably 50 mm. The upper limit of the distance between the electrodes is preferably 90 mm, more preferably 85 mm.
[0076]
　For example, in the hot-dip striped steel sheet manufactured by setting the distance between the electrodes to less than 40 mm as in the conventional case, the film thickness ratio of the Ni plating layer of the convex portion to the flat portion (thickness of the convex portion/thickness of the flat portion× 100) may be 2000% or more. On the other hand, in the hot-dip striped steel sheet manufactured 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. Further, if 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 surface portion to 300% or less when the hot-dip striped steel sheet is formed.
[0077]
　In the pre-plating step, the average deposition amount of Ni pre-plating on one side is 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 surface portion of the striped steel sheet after hot dipping is less than 0.05 μm, and non-plating is likely to occur. If the average adhesion amount exceeds 3 g/m 2 , the Ni plating layer remaining on the protrusions after hot dipping becomes excessive, and it becomes difficult to make the thickness of the Ni plating layer on the protrusions 0.4 μm or less.
[0078]
　The Ni deposition amount of the Ni pre-plating may be measured based on the following procedure a to procedure e before the hot dipping of the Zn-based alloy.
　Procedure a: Dissolve a Ni pre-plated steel plate with 30 mass% nitric acid (solution A).
　Step b: A sample is taken from the vicinity of the sample used in step a, the Ni pre-plated layer is removed by grinding or the like, and then the sample is dissolved with 30% by mass nitric acid (solution B).
　Step c: The amount of Fe and the amount of Ni dissolved in the solution B are obtained by ICP, and the ratio between the amount of Fe and the amount of Ni is obtained.
　Step d: The amount of Fe dissolved in the solution A is determined by ICP, and the amount of Ni dissolved from the base steel sheet is determined from the ratio calculated in step c.
　Step e: The amount of Ni dissolved in the solution A is determined by ICP, and the amount of Ni derived from the base steel sheet calculated in step d is subtracted to calculate the amount of Ni derived from the Ni pre-plated layer. The amount of Ni derived from the Ni pre-plated layer is converted into the amount of adhesion per unit area.
[0079]
　Note that, depending on the design of the electrolytic cell, in the continuous electroplating equipment for steel strips, edge overcoating may occur at the widthwise ends of the steel sheet due to current concentration. Therefore, when calculating the above-mentioned average adhesion amount, you may exclude the width direction edge part (for example, the area|region of 50 mm from both ends) of a steel strip from a measurement object.
[0080]
　In the hot dipping process, a striped steel sheet (steel strip) pre-plated with Ni is preheated in a non-oxidizing atmosphere, and then continuously passed through a hot dipping bath (continuous dipping in a hot dipping bath). The non-oxidizing atmosphere is, for example, a mixed gas of nitrogen and hydrogen. The preheating temperature is preferably in the range of [plating bath temperature+10° C.] to [plating bath temperature+50° C.]. If the preheating temperature is low, non-plating is likely to occur frequently. In the preheating, it is preferable that the steel sheet is rapidly heated so that the time at which the temperature is 350° C. or higher is 40 seconds or less. By shortening the time during which the steel plate is at 350° C. or higher, Ni can be prevented from diffusing into the base steel plate, and thus a sufficient Ni pre-plating amount for preventing non-plating can be secured.
[0081]
　The striped steel sheet preheated in a non-oxidizing atmosphere has Al: more than 1.0% and 26% or less, Mg: 0.05 to 10%, Si: 0 to 1.0%, Sn: 0 to if necessary. A hot dip zinc-based alloy plating bath containing 3.0% and Ca: 0 to 1.0% is passed (immersed in the hot dip bath). The temperature of the plating bath is preferably in the range of [melting point of molten Zn-based alloy + 20°C] to [melting point of molten Zn-based alloy + 50°C]. The striped steel sheet is immersed in a plating bath, preferably for 1 to 6 seconds, then wiped, and if necessary, cooled by steam spray or the like.
[0082]
　In the hot dip coating step, the average amount of adhesion of the hot dip layer on one side is 60 to 400 g/m 2 . If the average adhesion amount is less than 60 g/m 2 , the corrosion resistance may be insufficient. If the average adhesion amount exceeds 400 g/m 2 , excessive adhesion of the hot-dip coating layer may cause drooling of the plating and impair the appearance.
[0083]
　The chemical composition of the hot dip plating bath and the amount of the hot dip deposited can be measured using the ICP emission spectroscopy as in the above. Note that the chemical composition of the hot dip bath may be measured by ICP based on the sample taken from the hot dip bath instead of the sample taken from the hot-dip striped steel sheet.
Example 1
[0084]
　Next, the effects of one aspect of the present invention will be described in more detail with reference to Examples. The conditions in the Examples are one example of conditions adopted to confirm the feasibility and effects of the present invention. However, the present invention is not limited to this one condition example. The present invention can employ various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.
[0085]
　A hot rolled striped steel plate having a thickness of 2.3 mm was used as a plating original plate.
　The shape of this striped steel plate (base steel plate) was the same as in FIGS. 1A to 1C. In the figure, A, B, C, D, E, and H are as follows, respectively.
　A: The array angle of the convex portions with respect to the rolling direction.
　B: Length of one convex portion.
　C: Maximum width for one convex portion.
　D: Minimum width for one convex portion.
　E: Array pitch of convex portions.
　H: Height of convex portion.
　This striped steel plate is a hot rolled Al killed steel and has an angle A=45°, a width C=5.1 mm, a length B=25.3 mm, a height H=1.5 mm and a pitch E=28.6 mm. It was Thus, the striped steel plate in which the convex portions were regularly arranged was pickled, and Ni pre-plating was performed at various distances between the electrodes to change the average amount of deposited Ni. Tables 1 and 2 show conditions for Ni pre-plating. The electrolysis efficiency was about 80%. The striped steel sheet obtained had a cross-sectional structure as shown in FIG.
[0086]
[table 1]

[0087]
　The Ni-pre-plated steel sheet was hot-dipped with a Zn-based alloy using a Zn-based alloy hot-dip bath shown in Table 2. Table 2 also shows the temperature of the Zn-based alloy hot-dip bath. In performing hot dipping of a Zn-based alloy, the steel sheet is heated to a Zn-based alloy plating bath temperature of +30° C. in a non-oxidizing atmosphere (N 2 -2% H 2 ) at a heating rate of 10° C./sec, and the above atmosphere is applied. After cooling to a plating bath temperature of +10° C. therein, the steel sheet was immersed in the plating bath. The immersion time was 3 seconds, and the amount of hot-dip coating was adjusted by the hot-dip coating amount adjusting device on the outlet side of the hot-dip coating device.
[0088]
[Table 2]

[0089]
　Regarding the obtained hot-dip striped steel sheet, it was confirmed that the base material steel sheet, the Ni-plated layer, and the hot-dip plated layer were present in the cross-sectional structure based on the above-described observation and measurement methods, and the convex portion and the flat surface portion were formed on the plate surface. It was confirmed to have and. Further, the film thickness of the Ni plating layer of the convex portion, the film thickness of the Ni plating layer of the flat surface portion, the film thickness ratio of the Ni plating layer of the convex portion to the flat surface portion (thickness of the convex portion/thickness of the flat portion×100) The adhesion amount of the hot dip coating layer, the chemical composition of the hot dip coating layer, the coverage of the hot dip coating layer, the Ni adhering amount of the Ni pre-plating, the chemical composition of the hot dipping bath, etc.
[0090]
　Moreover, the obtained hot dip plated strip steel sheet was evaluated based on the following methods.
[0091]
　Corrosion test after abrasion
　Put a steel plate with a thickness of 5 mm of styrene-butadiene rubber on a 100 mm x 50 mm sample, put a 1 kg weight on it, and reciprocally vibrate in the lateral direction (stroke: 30 mm, number of reciprocations of 1000). Times) to abrade the plating. The abraded steel plate is exposed to the exposure platform to the south at an inclination of 45° to the ground, and once a week in a rain environment, 5 ml of a 5% NaCl aqueous solution is sprayed at 20 ml each time, and the test is continued for one month. did. After continuing for one month, the red rust generation area ratio in the vicinity of the convex portion was evaluated. For the evaluation of the red rust occurrence area ratio, WinROOF (image analysis software) manufactured by Mitani Corporation was used, and the area of ​​the red rust occurrence portion was measured to calculate the area ratio. The area ratio of the red rust occurrence portion was measured by extracting the color of red rust by color extraction. When the area ratio of red rust generated was 5% or more, it was determined that the corrosion resistance after abrasion was poor. In the table, the red rust occurrence area ratio: less than 5% is indicated by "Good", and the red rust occurrence area ratio: 5% or more is indicated by "Bad".
[0092]

　Prepare a 100 mm square sample of 　plating appearance , observe the plating surface from the thickness direction, and determine the area ratio (referred to as "dross area ratio") of the area where the plating appearance is deteriorated due to dross, manufactured by Mitani Corporation. It was measured using WinROOF (image analysis software). When the dross area ratio was 20% or more, the plating appearance was judged to be poor. In the table, dross area ratio: less than 20% is shown by "Good", and dross area ratio: 20% or more is shown by "Bad".
[0093]

　After V-bending the 　workability sample to 90°, a polyester adhesive tape made by Nitto Denko was attached to the outside of the bent part, the tape was peeled off, and it was confirmed whether or not the peeled material from the plating layer adhered to the tape. did. When the peeled material from the plating layer adhered to the tape, the workability was determined to be poor. In the table, "Good" is shown when there is no peeled material and "Bad" when there is peeled material.
[0094]
　Table 3 shows the production results and evaluation results of the produced hot-dip striped steel sheet. 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 to the flat surface portion (thickness of the convex portion/thickness of the flat portion×100).
[0095]
[Table 3]

[0096]
　In Comparative Example 1, since the distance between the electrodes at the time of performing Ni pre-plating is not appropriate, the thickness of the Ni plating layer on the convex portion exceeds 0.4 μm and the thickness of the Ni plating layer on the flat portion is 0.05 μm. Was less than As a result, plating failure due to non-plating occurred, and sufficient corrosion resistance could not be obtained in the corrosion test after abrasion.
　In Comparative Example 2, since the amount of Ni pre-plating deposited was small, the film thickness of the Ni plating layer on the flat surface portion of the striped 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, since the amount of Ni pre-plated was large, the film thickness of the Ni plating layer on the convex portion exceeded 0.4 μm. As a result, sufficient corrosion resistance could not be obtained in the corrosion test after abrasion.
　In Comparative Example 4, since the amount of Al in the Zn-based alloy hot-dip layer was small, sufficient corrosion resistance could not be obtained, and the plating appearance was also poor.
　In Comparative Example 5, since the amount of Al in the hot dip coating layer of the Zn-based alloy was large, the plating appearance was poor, the workability was not sufficient, and the hot-dip striped steel sheet was industrially unfavorable.
　In Comparative Example 6, since the amount of Mg in the Zn-based alloy hot-dip layer was small, sufficient corrosion resistance could not be obtained.
　In Comparative Example 7, the amount of Mg in the hot dip coating layer of the Zn-based alloy was large, so that the appearance of plating was poor, and the strip steel sheet was unfavorable industrially.
　In Comparative Example 8, since the amount of the Zn-based alloy hot-dip coating layer deposited was small, sufficient corrosion resistance could not be obtained.
　On the other hand, in Examples 1 to 10, generation of non-plating was suppressed and sufficient corrosion resistance was obtained even after abrasion. In addition, the plating appearance and workability were also satisfactory.
Industrial availability
[0097]
　According to the above aspect of the present invention, there is provided a hot-dip striped steel sheet in which the occurrence of non-plating is suppressed, and in which corrosion when the hot-dip plated layer is worn and the Ni-plated layer is exposed is also suppressed, and a method for manufacturing the same. You can Therefore, the industrial availability is high.
Explanation of symbols
[0098]
　　DESCRIPTION OF SYMBOLS 1... Convex part,
　　2... Plane part,
　　3... Zn-based alloy hot-dip layer,
　　4... Ni plating layer,
　　5... Base material steel plate
The scope of the claims
[Claim 1]
　Melting having a base material steel plate, a Ni plating layer arranged on the surface of the base material steel plate, and a hot dip coating layer arranged on the surface of the Ni plating layer, and having a convex portion and a flat surface portion on the plate surface The plated striped steel sheet,
　wherein the thickness of the Ni plating layer on the convex portion is 0.07 to 0.4 μm per side, and the
　thickness of the Ni plating layer on the flat portion is 0.05 to 0 per side. .35
　μm, the thickness of the Ni plating layer of the convex portion is more than 100% and 400% or less with respect to the thickness of the Ni plating layer of the flat portion, and
　the adhesion of the hot-dip plating layer is The amount is 60 to 400 g/m 2 per side , and the
　hot-dip plated layer has a chemical composition of, by mass%, Al: more than 1.0% and 26% or less, Mg: 0.05 to 10%, Si:0. ~1.0%, Sn:0~3.0%, Ca:0~1.0%, the balance consisting of Zn and impurities, hot-dip striped steel sheet.
[Claim 2]
　The thickness of the Ni plating layer of the convex portion is more than 100% and 300% or less of the thickness of the Ni plating layer of the flat portion. Hot-dip striped steel sheet.
[Claim 3]
　The hot-dip striped steel sheet according to claim 1 or 2, wherein the film thickness of the Ni plating layer of the protrusion is 0.07 to 0.3 µm per one surface.
[Claim 4]
　The hot-dip plated layer contains Al: 4.0 to 25.0% and Mg: 1.5 to 8.0% in mass% as the chemical composition. The hot-dip striped steel sheet according to any one of 3 above.
[Claim 5]
　The hot-dip plating layer has, as the chemical composition, mass% of Si: 0.05 to 1.0%, Sn: 0.1 to 3.0%, and Ca: 0.01 to 1.0%. The hot-dip striped steel sheet according to any one of claims 1 to 4, comprising at least one.
[Claim 6]
　The coating rate of the hot-dip plating layer is 99 to 100% in area% with respect to the plate surface when viewed from the thickness direction, according to any one of claims 1 to 5. Hot-dip striped steel sheet.
[Claim 7]
　A method for manufacturing a hot-dip striped steel sheet according to any one of claims 1 to 6
　,
　comprising a rolling step of providing a rolling surface of the steel sheet with convex portions and flat portions, and a steel sheet that has undergone the rolling step. a pre-plating step of performing Ni pre-plating, in
　a hot dipping step of performing molten plating steel sheet which has undergone the pre-plating process
comprises a,
　in the pre-plating process, disposed opposite the rolling surface and the anode surface of the steel plate Then, the inter-electrode distance between the convex portion of the rolled surface and the anode is controlled to 40 to 100 mm, and the electric Ni plating is performed under the condition that the amount of plating adhered per one surface is 0.5 to 3 g/m 2 on average .
　In the hot dip plating step, the steel sheet is heated and, in mass %, Al: more than 1.0 and 26% or less, Mg: 0.05 to 10%, Si: 0 to 1.0%, Sn: 0 to 3.0. %, Ca: 0 to 1.0%, the rest is immersed in a hot dip plating bath consisting of Zn and impurities , and continuously applied under the condition that the coating adhesion amount on one surface is 60 to 400 g/m 2 on average. A
method for producing a hot-dip striped steel sheet , which comprises performing hot-dip coating .
[Claim 8]
　The method for manufacturing a hot-dip striped steel sheet according to claim 7, wherein the inter-electrode distance is controlled to 45 to 100 mm in the pre-plating step.